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v8/src/jsregexp.cc
svenpanne@chromium.org 3df99e7eb7 Thread the current isolate through a few places, avoiding Isolate::Current(). 
This removes approx. 12k calls of Isolate::Current() in string-tagcloud.

Review URL: https://chromiumcodereview.appspot.com/9490004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10856 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-02-28 10:32:02 +00:00

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// Copyright 2011 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "ast.h"
#include "compiler.h"
#include "execution.h"
#include "factory.h"
#include "jsregexp.h"
#include "platform.h"
#include "string-search.h"
#include "runtime.h"
#include "compilation-cache.h"
#include "string-stream.h"
#include "parser.h"
#include "regexp-macro-assembler.h"
#include "regexp-macro-assembler-tracer.h"
#include "regexp-macro-assembler-irregexp.h"
#include "regexp-stack.h"
#ifndef V8_INTERPRETED_REGEXP
#if V8_TARGET_ARCH_IA32
#include "ia32/regexp-macro-assembler-ia32.h"
#elif V8_TARGET_ARCH_X64
#include "x64/regexp-macro-assembler-x64.h"
#elif V8_TARGET_ARCH_ARM
#include "arm/regexp-macro-assembler-arm.h"
#elif V8_TARGET_ARCH_MIPS
#include "mips/regexp-macro-assembler-mips.h"
#else
#error Unsupported target architecture.
#endif
#endif
#include "interpreter-irregexp.h"
namespace v8 {
namespace internal {
Handle<Object> RegExpImpl::CreateRegExpLiteral(Handle<JSFunction> constructor,
Handle<String> pattern,
Handle<String> flags,
bool* has_pending_exception) {
// Call the construct code with 2 arguments.
Handle<Object> argv[] = { pattern, flags };
return Execution::New(constructor, ARRAY_SIZE(argv), argv,
has_pending_exception);
}
static JSRegExp::Flags RegExpFlagsFromString(Handle<String> str) {
int flags = JSRegExp::NONE;
for (int i = 0; i < str->length(); i++) {
switch (str->Get(i)) {
case 'i':
flags |= JSRegExp::IGNORE_CASE;
break;
case 'g':
flags |= JSRegExp::GLOBAL;
break;
case 'm':
flags |= JSRegExp::MULTILINE;
break;
}
}
return JSRegExp::Flags(flags);
}
static inline void ThrowRegExpException(Handle<JSRegExp> re,
Handle<String> pattern,
Handle<String> error_text,
const char* message) {
Isolate* isolate = re->GetIsolate();
Factory* factory = isolate->factory();
Handle<FixedArray> elements = factory->NewFixedArray(2);
elements->set(0, *pattern);
elements->set(1, *error_text);
Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
Handle<Object> regexp_err = factory->NewSyntaxError(message, array);
isolate->Throw(*regexp_err);
}
// Generic RegExp methods. Dispatches to implementation specific methods.
Handle<Object> RegExpImpl::Compile(Handle<JSRegExp> re,
Handle<String> pattern,
Handle<String> flag_str) {
Isolate* isolate = re->GetIsolate();
JSRegExp::Flags flags = RegExpFlagsFromString(flag_str);
CompilationCache* compilation_cache = isolate->compilation_cache();
Handle<FixedArray> cached = compilation_cache->LookupRegExp(pattern, flags);
bool in_cache = !cached.is_null();
LOG(isolate, RegExpCompileEvent(re, in_cache));
Handle<Object> result;
if (in_cache) {
re->set_data(*cached);
return re;
}
pattern = FlattenGetString(pattern);
ZoneScope zone_scope(isolate, DELETE_ON_EXIT);
PostponeInterruptsScope postpone(isolate);
RegExpCompileData parse_result;
FlatStringReader reader(isolate, pattern);
if (!RegExpParser::ParseRegExp(&reader, flags.is_multiline(),
&parse_result)) {
// Throw an exception if we fail to parse the pattern.
ThrowRegExpException(re,
pattern,
parse_result.error,
"malformed_regexp");
return Handle<Object>::null();
}
if (parse_result.simple && !flags.is_ignore_case()) {
// Parse-tree is a single atom that is equal to the pattern.
AtomCompile(re, pattern, flags, pattern);
} else if (parse_result.tree->IsAtom() &&
!flags.is_ignore_case() &&
parse_result.capture_count == 0) {
RegExpAtom* atom = parse_result.tree->AsAtom();
Vector<const uc16> atom_pattern = atom->data();
Handle<String> atom_string =
isolate->factory()->NewStringFromTwoByte(atom_pattern);
AtomCompile(re, pattern, flags, atom_string);
} else {
IrregexpInitialize(re, pattern, flags, parse_result.capture_count);
}
ASSERT(re->data()->IsFixedArray());
// Compilation succeeded so the data is set on the regexp
// and we can store it in the cache.
Handle<FixedArray> data(FixedArray::cast(re->data()));
compilation_cache->PutRegExp(pattern, flags, data);
return re;
}
Handle<Object> RegExpImpl::Exec(Handle<JSRegExp> regexp,
Handle<String> subject,
int index,
Handle<JSArray> last_match_info) {
switch (regexp->TypeTag()) {
case JSRegExp::ATOM:
return AtomExec(regexp, subject, index, last_match_info);
case JSRegExp::IRREGEXP: {
Handle<Object> result =
IrregexpExec(regexp, subject, index, last_match_info);
ASSERT(!result.is_null() ||
regexp->GetIsolate()->has_pending_exception());
return result;
}
default:
UNREACHABLE();
return Handle<Object>::null();
}
}
// RegExp Atom implementation: Simple string search using indexOf.
void RegExpImpl::AtomCompile(Handle<JSRegExp> re,
Handle<String> pattern,
JSRegExp::Flags flags,
Handle<String> match_pattern) {
re->GetIsolate()->factory()->SetRegExpAtomData(re,
JSRegExp::ATOM,
pattern,
flags,
match_pattern);
}
static void SetAtomLastCapture(FixedArray* array,
String* subject,
int from,
int to) {
NoHandleAllocation no_handles;
RegExpImpl::SetLastCaptureCount(array, 2);
RegExpImpl::SetLastSubject(array, subject);
RegExpImpl::SetLastInput(array, subject);
RegExpImpl::SetCapture(array, 0, from);
RegExpImpl::SetCapture(array, 1, to);
}
Handle<Object> RegExpImpl::AtomExec(Handle<JSRegExp> re,
Handle<String> subject,
int index,
Handle<JSArray> last_match_info) {
Isolate* isolate = re->GetIsolate();
ASSERT(0 <= index);
ASSERT(index <= subject->length());
if (!subject->IsFlat()) FlattenString(subject);
AssertNoAllocation no_heap_allocation; // ensure vectors stay valid
String* needle = String::cast(re->DataAt(JSRegExp::kAtomPatternIndex));
int needle_len = needle->length();
ASSERT(needle->IsFlat());
if (needle_len != 0) {
if (index + needle_len > subject->length()) {
return isolate->factory()->null_value();
}
String::FlatContent needle_content = needle->GetFlatContent();
String::FlatContent subject_content = subject->GetFlatContent();
ASSERT(needle_content.IsFlat());
ASSERT(subject_content.IsFlat());
// dispatch on type of strings
index = (needle_content.IsAscii()
? (subject_content.IsAscii()
? SearchString(isolate,
subject_content.ToAsciiVector(),
needle_content.ToAsciiVector(),
index)
: SearchString(isolate,
subject_content.ToUC16Vector(),
needle_content.ToAsciiVector(),
index))
: (subject_content.IsAscii()
? SearchString(isolate,
subject_content.ToAsciiVector(),
needle_content.ToUC16Vector(),
index)
: SearchString(isolate,
subject_content.ToUC16Vector(),
needle_content.ToUC16Vector(),
index)));
if (index == -1) return isolate->factory()->null_value();
}
ASSERT(last_match_info->HasFastElements());
{
NoHandleAllocation no_handles;
FixedArray* array = FixedArray::cast(last_match_info->elements());
SetAtomLastCapture(array, *subject, index, index + needle_len);
}
return last_match_info;
}
// Irregexp implementation.
// Ensures that the regexp object contains a compiled version of the
// source for either ASCII or non-ASCII strings.
// If the compiled version doesn't already exist, it is compiled
// from the source pattern.
// If compilation fails, an exception is thrown and this function
// returns false.
bool RegExpImpl::EnsureCompiledIrregexp(Handle<JSRegExp> re, bool is_ascii) {
Object* compiled_code = re->DataAt(JSRegExp::code_index(is_ascii));
#ifdef V8_INTERPRETED_REGEXP
if (compiled_code->IsByteArray()) return true;
#else // V8_INTERPRETED_REGEXP (RegExp native code)
if (compiled_code->IsCode()) return true;
#endif
// We could potentially have marked this as flushable, but have kept
// a saved version if we did not flush it yet.
Object* saved_code = re->DataAt(JSRegExp::saved_code_index(is_ascii));
if (saved_code->IsCode()) {
// Reinstate the code in the original place.
re->SetDataAt(JSRegExp::code_index(is_ascii), saved_code);
ASSERT(compiled_code->IsSmi());
return true;
}
return CompileIrregexp(re, is_ascii);
}
static bool CreateRegExpErrorObjectAndThrow(Handle<JSRegExp> re,
bool is_ascii,
Handle<String> error_message,
Isolate* isolate) {
Factory* factory = isolate->factory();
Handle<FixedArray> elements = factory->NewFixedArray(2);
elements->set(0, re->Pattern());
elements->set(1, *error_message);
Handle<JSArray> array = factory->NewJSArrayWithElements(elements);
Handle<Object> regexp_err =
factory->NewSyntaxError("malformed_regexp", array);
isolate->Throw(*regexp_err);
return false;
}
bool RegExpImpl::CompileIrregexp(Handle<JSRegExp> re, bool is_ascii) {
// Compile the RegExp.
Isolate* isolate = re->GetIsolate();
ZoneScope zone_scope(isolate, DELETE_ON_EXIT);
PostponeInterruptsScope postpone(isolate);
// If we had a compilation error the last time this is saved at the
// saved code index.
Object* entry = re->DataAt(JSRegExp::code_index(is_ascii));
// When arriving here entry can only be a smi, either representing an
// uncompiled regexp, a previous compilation error, or code that has
// been flushed.
ASSERT(entry->IsSmi());
int entry_value = Smi::cast(entry)->value();
ASSERT(entry_value == JSRegExp::kUninitializedValue ||
entry_value == JSRegExp::kCompilationErrorValue ||
(entry_value < JSRegExp::kCodeAgeMask && entry_value >= 0));
if (entry_value == JSRegExp::kCompilationErrorValue) {
// A previous compilation failed and threw an error which we store in
// the saved code index (we store the error message, not the actual
// error). Recreate the error object and throw it.
Object* error_string = re->DataAt(JSRegExp::saved_code_index(is_ascii));
ASSERT(error_string->IsString());
Handle<String> error_message(String::cast(error_string));
CreateRegExpErrorObjectAndThrow(re, is_ascii, error_message, isolate);
return false;
}
JSRegExp::Flags flags = re->GetFlags();
Handle<String> pattern(re->Pattern());
if (!pattern->IsFlat()) FlattenString(pattern);
RegExpCompileData compile_data;
FlatStringReader reader(isolate, pattern);
if (!RegExpParser::ParseRegExp(&reader, flags.is_multiline(),
&compile_data)) {
// Throw an exception if we fail to parse the pattern.
// THIS SHOULD NOT HAPPEN. We already pre-parsed it successfully once.
ThrowRegExpException(re,
pattern,
compile_data.error,
"malformed_regexp");
return false;
}
RegExpEngine::CompilationResult result =
RegExpEngine::Compile(&compile_data,
flags.is_ignore_case(),
flags.is_multiline(),
pattern,
is_ascii);
if (result.error_message != NULL) {
// Unable to compile regexp.
Handle<String> error_message =
isolate->factory()->NewStringFromUtf8(CStrVector(result.error_message));
CreateRegExpErrorObjectAndThrow(re, is_ascii, error_message, isolate);
return false;
}
Handle<FixedArray> data = Handle<FixedArray>(FixedArray::cast(re->data()));
data->set(JSRegExp::code_index(is_ascii), result.code);
int register_max = IrregexpMaxRegisterCount(*data);
if (result.num_registers > register_max) {
SetIrregexpMaxRegisterCount(*data, result.num_registers);
}
return true;
}
int RegExpImpl::IrregexpMaxRegisterCount(FixedArray* re) {
return Smi::cast(
re->get(JSRegExp::kIrregexpMaxRegisterCountIndex))->value();
}
void RegExpImpl::SetIrregexpMaxRegisterCount(FixedArray* re, int value) {
re->set(JSRegExp::kIrregexpMaxRegisterCountIndex, Smi::FromInt(value));
}
int RegExpImpl::IrregexpNumberOfCaptures(FixedArray* re) {
return Smi::cast(re->get(JSRegExp::kIrregexpCaptureCountIndex))->value();
}
int RegExpImpl::IrregexpNumberOfRegisters(FixedArray* re) {
return Smi::cast(re->get(JSRegExp::kIrregexpMaxRegisterCountIndex))->value();
}
ByteArray* RegExpImpl::IrregexpByteCode(FixedArray* re, bool is_ascii) {
return ByteArray::cast(re->get(JSRegExp::code_index(is_ascii)));
}
Code* RegExpImpl::IrregexpNativeCode(FixedArray* re, bool is_ascii) {
return Code::cast(re->get(JSRegExp::code_index(is_ascii)));
}
void RegExpImpl::IrregexpInitialize(Handle<JSRegExp> re,
Handle<String> pattern,
JSRegExp::Flags flags,
int capture_count) {
// Initialize compiled code entries to null.
re->GetIsolate()->factory()->SetRegExpIrregexpData(re,
JSRegExp::IRREGEXP,
pattern,
flags,
capture_count);
}
int RegExpImpl::IrregexpPrepare(Handle<JSRegExp> regexp,
Handle<String> subject) {
if (!subject->IsFlat()) FlattenString(subject);
// Check the asciiness of the underlying storage.
bool is_ascii = subject->IsAsciiRepresentationUnderneath();
if (!EnsureCompiledIrregexp(regexp, is_ascii)) return -1;
#ifdef V8_INTERPRETED_REGEXP
// Byte-code regexp needs space allocated for all its registers.
return IrregexpNumberOfRegisters(FixedArray::cast(regexp->data()));
#else // V8_INTERPRETED_REGEXP
// Native regexp only needs room to output captures. Registers are handled
// internally.
return (IrregexpNumberOfCaptures(FixedArray::cast(regexp->data())) + 1) * 2;
#endif // V8_INTERPRETED_REGEXP
}
RegExpImpl::IrregexpResult RegExpImpl::IrregexpExecOnce(
Handle<JSRegExp> regexp,
Handle<String> subject,
int index,
Vector<int> output) {
Isolate* isolate = regexp->GetIsolate();
Handle<FixedArray> irregexp(FixedArray::cast(regexp->data()), isolate);
ASSERT(index >= 0);
ASSERT(index <= subject->length());
ASSERT(subject->IsFlat());
bool is_ascii = subject->IsAsciiRepresentationUnderneath();
#ifndef V8_INTERPRETED_REGEXP
ASSERT(output.length() >= (IrregexpNumberOfCaptures(*irregexp) + 1) * 2);
do {
EnsureCompiledIrregexp(regexp, is_ascii);
Handle<Code> code(IrregexpNativeCode(*irregexp, is_ascii), isolate);
NativeRegExpMacroAssembler::Result res =
NativeRegExpMacroAssembler::Match(code,
subject,
output.start(),
output.length(),
index,
isolate);
if (res != NativeRegExpMacroAssembler::RETRY) {
ASSERT(res != NativeRegExpMacroAssembler::EXCEPTION ||
isolate->has_pending_exception());
STATIC_ASSERT(
static_cast<int>(NativeRegExpMacroAssembler::SUCCESS) == RE_SUCCESS);
STATIC_ASSERT(
static_cast<int>(NativeRegExpMacroAssembler::FAILURE) == RE_FAILURE);
STATIC_ASSERT(static_cast<int>(NativeRegExpMacroAssembler::EXCEPTION)
== RE_EXCEPTION);
return static_cast<IrregexpResult>(res);
}
// If result is RETRY, the string has changed representation, and we
// must restart from scratch.
// In this case, it means we must make sure we are prepared to handle
// the, potentially, different subject (the string can switch between
// being internal and external, and even between being ASCII and UC16,
// but the characters are always the same).
IrregexpPrepare(regexp, subject);
is_ascii = subject->IsAsciiRepresentationUnderneath();
} while (true);
UNREACHABLE();
return RE_EXCEPTION;
#else // V8_INTERPRETED_REGEXP
ASSERT(output.length() >= IrregexpNumberOfRegisters(*irregexp));
// We must have done EnsureCompiledIrregexp, so we can get the number of
// registers.
int* register_vector = output.start();
int number_of_capture_registers =
(IrregexpNumberOfCaptures(*irregexp) + 1) * 2;
for (int i = number_of_capture_registers - 1; i >= 0; i--) {
register_vector[i] = -1;
}
Handle<ByteArray> byte_codes(IrregexpByteCode(*irregexp, is_ascii), isolate);
IrregexpResult result = IrregexpInterpreter::Match(isolate,
byte_codes,
subject,
register_vector,
index);
if (result == RE_EXCEPTION) {
ASSERT(!isolate->has_pending_exception());
isolate->StackOverflow();
}
return result;
#endif // V8_INTERPRETED_REGEXP
}
Handle<Object> RegExpImpl::IrregexpExec(Handle<JSRegExp> jsregexp,
Handle<String> subject,
int previous_index,
Handle<JSArray> last_match_info) {
Isolate* isolate = jsregexp->GetIsolate();
ASSERT_EQ(jsregexp->TypeTag(), JSRegExp::IRREGEXP);
// Prepare space for the return values.
#ifdef V8_INTERPRETED_REGEXP
#ifdef DEBUG
if (FLAG_trace_regexp_bytecodes) {
String* pattern = jsregexp->Pattern();
PrintF("\n\nRegexp match: /%s/\n\n", *(pattern->ToCString()));
PrintF("\n\nSubject string: '%s'\n\n", *(subject->ToCString()));
}
#endif
#endif
int required_registers = RegExpImpl::IrregexpPrepare(jsregexp, subject);
if (required_registers < 0) {
// Compiling failed with an exception.
ASSERT(isolate->has_pending_exception());
return Handle<Object>::null();
}
OffsetsVector registers(required_registers, isolate);
IrregexpResult res = RegExpImpl::IrregexpExecOnce(
jsregexp, subject, previous_index, Vector<int>(registers.vector(),
registers.length()));
if (res == RE_SUCCESS) {
int capture_register_count =
(IrregexpNumberOfCaptures(FixedArray::cast(jsregexp->data())) + 1) * 2;
last_match_info->EnsureSize(capture_register_count + kLastMatchOverhead);
AssertNoAllocation no_gc;
int* register_vector = registers.vector();
FixedArray* array = FixedArray::cast(last_match_info->elements());
for (int i = 0; i < capture_register_count; i += 2) {
SetCapture(array, i, register_vector[i]);
SetCapture(array, i + 1, register_vector[i + 1]);
}
SetLastCaptureCount(array, capture_register_count);
SetLastSubject(array, *subject);
SetLastInput(array, *subject);
return last_match_info;
}
if (res == RE_EXCEPTION) {
ASSERT(isolate->has_pending_exception());
return Handle<Object>::null();
}
ASSERT(res == RE_FAILURE);
return isolate->factory()->null_value();
}
// -------------------------------------------------------------------
// Implementation of the Irregexp regular expression engine.
//
// The Irregexp regular expression engine is intended to be a complete
// implementation of ECMAScript regular expressions. It generates either
// bytecodes or native code.
// The Irregexp regexp engine is structured in three steps.
// 1) The parser generates an abstract syntax tree. See ast.cc.
// 2) From the AST a node network is created. The nodes are all
// subclasses of RegExpNode. The nodes represent states when
// executing a regular expression. Several optimizations are
// performed on the node network.
// 3) From the nodes we generate either byte codes or native code
// that can actually execute the regular expression (perform
// the search). The code generation step is described in more
// detail below.
// Code generation.
//
// The nodes are divided into four main categories.
// * Choice nodes
// These represent places where the regular expression can
// match in more than one way. For example on entry to an
// alternation (foo|bar) or a repetition (*, +, ? or {}).
// * Action nodes
// These represent places where some action should be
// performed. Examples include recording the current position
// in the input string to a register (in order to implement
// captures) or other actions on register for example in order
// to implement the counters needed for {} repetitions.
// * Matching nodes
// These attempt to match some element part of the input string.
// Examples of elements include character classes, plain strings
// or back references.
// * End nodes
// These are used to implement the actions required on finding
// a successful match or failing to find a match.
//
// The code generated (whether as byte codes or native code) maintains
// some state as it runs. This consists of the following elements:
//
// * The capture registers. Used for string captures.
// * Other registers. Used for counters etc.
// * The current position.
// * The stack of backtracking information. Used when a matching node
// fails to find a match and needs to try an alternative.
//
// Conceptual regular expression execution model:
//
// There is a simple conceptual model of regular expression execution
// which will be presented first. The actual code generated is a more
// efficient simulation of the simple conceptual model:
//
// * Choice nodes are implemented as follows:
// For each choice except the last {
// push current position
// push backtrack code location
// <generate code to test for choice>
// backtrack code location:
// pop current position
// }
// <generate code to test for last choice>
//
// * Actions nodes are generated as follows
// <push affected registers on backtrack stack>
// <generate code to perform action>
// push backtrack code location
// <generate code to test for following nodes>
// backtrack code location:
// <pop affected registers to restore their state>
// <pop backtrack location from stack and go to it>
//
// * Matching nodes are generated as follows:
// if input string matches at current position
// update current position
// <generate code to test for following nodes>
// else
// <pop backtrack location from stack and go to it>
//
// Thus it can be seen that the current position is saved and restored
// by the choice nodes, whereas the registers are saved and restored by
// by the action nodes that manipulate them.
//
// The other interesting aspect of this model is that nodes are generated
// at the point where they are needed by a recursive call to Emit(). If
// the node has already been code generated then the Emit() call will
// generate a jump to the previously generated code instead. In order to
// limit recursion it is possible for the Emit() function to put the node
// on a work list for later generation and instead generate a jump. The
// destination of the jump is resolved later when the code is generated.
//
// Actual regular expression code generation.
//
// Code generation is actually more complicated than the above. In order
// to improve the efficiency of the generated code some optimizations are
// performed
//
// * Choice nodes have 1-character lookahead.
// A choice node looks at the following character and eliminates some of
// the choices immediately based on that character. This is not yet
// implemented.
// * Simple greedy loops store reduced backtracking information.
// A quantifier like /.*foo/m will greedily match the whole input. It will
// then need to backtrack to a point where it can match "foo". The naive
// implementation of this would push each character position onto the
// backtracking stack, then pop them off one by one. This would use space
// proportional to the length of the input string. However since the "."
// can only match in one way and always has a constant length (in this case
// of 1) it suffices to store the current position on the top of the stack
// once. Matching now becomes merely incrementing the current position and
// backtracking becomes decrementing the current position and checking the
// result against the stored current position. This is faster and saves
// space.
// * The current state is virtualized.
// This is used to defer expensive operations until it is clear that they
// are needed and to generate code for a node more than once, allowing
// specialized an efficient versions of the code to be created. This is
// explained in the section below.
//
// Execution state virtualization.
//
// Instead of emitting code, nodes that manipulate the state can record their
// manipulation in an object called the Trace. The Trace object can record a
// current position offset, an optional backtrack code location on the top of
// the virtualized backtrack stack and some register changes. When a node is
// to be emitted it can flush the Trace or update it. Flushing the Trace
// will emit code to bring the actual state into line with the virtual state.
// Avoiding flushing the state can postpone some work (e.g. updates of capture
// registers). Postponing work can save time when executing the regular
// expression since it may be found that the work never has to be done as a
// failure to match can occur. In addition it is much faster to jump to a
// known backtrack code location than it is to pop an unknown backtrack
// location from the stack and jump there.
//
// The virtual state found in the Trace affects code generation. For example
// the virtual state contains the difference between the actual current
// position and the virtual current position, and matching code needs to use
// this offset to attempt a match in the correct location of the input
// string. Therefore code generated for a non-trivial trace is specialized
// to that trace. The code generator therefore has the ability to generate
// code for each node several times. In order to limit the size of the
// generated code there is an arbitrary limit on how many specialized sets of
// code may be generated for a given node. If the limit is reached, the
// trace is flushed and a generic version of the code for a node is emitted.
// This is subsequently used for that node. The code emitted for non-generic
// trace is not recorded in the node and so it cannot currently be reused in
// the event that code generation is requested for an identical trace.
void RegExpTree::AppendToText(RegExpText* text) {
UNREACHABLE();
}
void RegExpAtom::AppendToText(RegExpText* text) {
text->AddElement(TextElement::Atom(this));
}
void RegExpCharacterClass::AppendToText(RegExpText* text) {
text->AddElement(TextElement::CharClass(this));
}
void RegExpText::AppendToText(RegExpText* text) {
for (int i = 0; i < elements()->length(); i++)
text->AddElement(elements()->at(i));
}
TextElement TextElement::Atom(RegExpAtom* atom) {
TextElement result = TextElement(ATOM);
result.data.u_atom = atom;
return result;
}
TextElement TextElement::CharClass(
RegExpCharacterClass* char_class) {
TextElement result = TextElement(CHAR_CLASS);
result.data.u_char_class = char_class;
return result;
}
int TextElement::length() {
if (type == ATOM) {
return data.u_atom->length();
} else {
ASSERT(type == CHAR_CLASS);
return 1;
}
}
DispatchTable* ChoiceNode::GetTable(bool ignore_case) {
if (table_ == NULL) {
table_ = new DispatchTable();
DispatchTableConstructor cons(table_, ignore_case);
cons.BuildTable(this);
}
return table_;
}
class RegExpCompiler {
public:
RegExpCompiler(int capture_count, bool ignore_case, bool is_ascii);
int AllocateRegister() {
if (next_register_ >= RegExpMacroAssembler::kMaxRegister) {
reg_exp_too_big_ = true;
return next_register_;
}
return next_register_++;
}
RegExpEngine::CompilationResult Assemble(RegExpMacroAssembler* assembler,
RegExpNode* start,
int capture_count,
Handle<String> pattern);
inline void AddWork(RegExpNode* node) { work_list_->Add(node); }
static const int kImplementationOffset = 0;
static const int kNumberOfRegistersOffset = 0;
static const int kCodeOffset = 1;
RegExpMacroAssembler* macro_assembler() { return macro_assembler_; }
EndNode* accept() { return accept_; }
static const int kMaxRecursion = 100;
inline int recursion_depth() { return recursion_depth_; }
inline void IncrementRecursionDepth() { recursion_depth_++; }
inline void DecrementRecursionDepth() { recursion_depth_--; }
void SetRegExpTooBig() { reg_exp_too_big_ = true; }
inline bool ignore_case() { return ignore_case_; }
inline bool ascii() { return ascii_; }
int current_expansion_factor() { return current_expansion_factor_; }
void set_current_expansion_factor(int value) {
current_expansion_factor_ = value;
}
static const int kNoRegister = -1;
private:
EndNode* accept_;
int next_register_;
List<RegExpNode*>* work_list_;
int recursion_depth_;
RegExpMacroAssembler* macro_assembler_;
bool ignore_case_;
bool ascii_;
bool reg_exp_too_big_;
int current_expansion_factor_;
};
class RecursionCheck {
public:
explicit RecursionCheck(RegExpCompiler* compiler) : compiler_(compiler) {
compiler->IncrementRecursionDepth();
}
~RecursionCheck() { compiler_->DecrementRecursionDepth(); }
private:
RegExpCompiler* compiler_;
};
static RegExpEngine::CompilationResult IrregexpRegExpTooBig() {
return RegExpEngine::CompilationResult("RegExp too big");
}
// Attempts to compile the regexp using an Irregexp code generator. Returns
// a fixed array or a null handle depending on whether it succeeded.
RegExpCompiler::RegExpCompiler(int capture_count, bool ignore_case, bool ascii)
: next_register_(2 * (capture_count + 1)),
work_list_(NULL),
recursion_depth_(0),
ignore_case_(ignore_case),
ascii_(ascii),
reg_exp_too_big_(false),
current_expansion_factor_(1) {
accept_ = new EndNode(EndNode::ACCEPT);
ASSERT(next_register_ - 1 <= RegExpMacroAssembler::kMaxRegister);
}
RegExpEngine::CompilationResult RegExpCompiler::Assemble(
RegExpMacroAssembler* macro_assembler,
RegExpNode* start,
int capture_count,
Handle<String> pattern) {
Heap* heap = pattern->GetHeap();
bool use_slow_safe_regexp_compiler = false;
if (heap->total_regexp_code_generated() >
RegExpImpl::kRegWxpCompiledLimit &&
heap->isolate()->memory_allocator()->SizeExecutable() >
RegExpImpl::kRegExpExecutableMemoryLimit) {
use_slow_safe_regexp_compiler = true;
}
macro_assembler->set_slow_safe(use_slow_safe_regexp_compiler);
#ifdef DEBUG
if (FLAG_trace_regexp_assembler)
macro_assembler_ = new RegExpMacroAssemblerTracer(macro_assembler);
else
#endif
macro_assembler_ = macro_assembler;
List <RegExpNode*> work_list(0);
work_list_ = &work_list;
Label fail;
macro_assembler_->PushBacktrack(&fail);
Trace new_trace;
start->Emit(this, &new_trace);
macro_assembler_->Bind(&fail);
macro_assembler_->Fail();
while (!work_list.is_empty()) {
work_list.RemoveLast()->Emit(this, &new_trace);
}
if (reg_exp_too_big_) return IrregexpRegExpTooBig();
Handle<HeapObject> code = macro_assembler_->GetCode(pattern);
heap->IncreaseTotalRegexpCodeGenerated(code->Size());
work_list_ = NULL;
#ifdef DEBUG
if (FLAG_print_code) {
Handle<Code>::cast(code)->Disassemble(*pattern->ToCString());
}
if (FLAG_trace_regexp_assembler) {
delete macro_assembler_;
}
#endif
return RegExpEngine::CompilationResult(*code, next_register_);
}
bool Trace::DeferredAction::Mentions(int that) {
if (type() == ActionNode::CLEAR_CAPTURES) {
Interval range = static_cast<DeferredClearCaptures*>(this)->range();
return range.Contains(that);
} else {
return reg() == that;
}
}
bool Trace::mentions_reg(int reg) {
for (DeferredAction* action = actions_;
action != NULL;
action = action->next()) {
if (action->Mentions(reg))
return true;
}
return false;
}
bool Trace::GetStoredPosition(int reg, int* cp_offset) {
ASSERT_EQ(0, *cp_offset);
for (DeferredAction* action = actions_;
action != NULL;
action = action->next()) {
if (action->Mentions(reg)) {
if (action->type() == ActionNode::STORE_POSITION) {
*cp_offset = static_cast<DeferredCapture*>(action)->cp_offset();
return true;
} else {
return false;
}
}
}
return false;
}
int Trace::FindAffectedRegisters(OutSet* affected_registers) {
int max_register = RegExpCompiler::kNoRegister;
for (DeferredAction* action = actions_;
action != NULL;
action = action->next()) {
if (action->type() == ActionNode::CLEAR_CAPTURES) {
Interval range = static_cast<DeferredClearCaptures*>(action)->range();
for (int i = range.from(); i <= range.to(); i++)
affected_registers->Set(i);
if (range.to() > max_register) max_register = range.to();
} else {
affected_registers->Set(action->reg());
if (action->reg() > max_register) max_register = action->reg();
}
}
return max_register;
}
void Trace::RestoreAffectedRegisters(RegExpMacroAssembler* assembler,
int max_register,
OutSet& registers_to_pop,
OutSet& registers_to_clear) {
for (int reg = max_register; reg >= 0; reg--) {
if (registers_to_pop.Get(reg)) assembler->PopRegister(reg);
else if (registers_to_clear.Get(reg)) {
int clear_to = reg;
while (reg > 0 && registers_to_clear.Get(reg - 1)) {
reg--;
}
assembler->ClearRegisters(reg, clear_to);
}
}
}
void Trace::PerformDeferredActions(RegExpMacroAssembler* assembler,
int max_register,
OutSet& affected_registers,
OutSet* registers_to_pop,
OutSet* registers_to_clear) {
// The "+1" is to avoid a push_limit of zero if stack_limit_slack() is 1.
const int push_limit = (assembler->stack_limit_slack() + 1) / 2;
// Count pushes performed to force a stack limit check occasionally.
int pushes = 0;
for (int reg = 0; reg <= max_register; reg++) {
if (!affected_registers.Get(reg)) {
continue;
}
// The chronologically first deferred action in the trace
// is used to infer the action needed to restore a register
// to its previous state (or not, if it's safe to ignore it).
enum DeferredActionUndoType { IGNORE, RESTORE, CLEAR };
DeferredActionUndoType undo_action = IGNORE;
int value = 0;
bool absolute = false;
bool clear = false;
int store_position = -1;
// This is a little tricky because we are scanning the actions in reverse
// historical order (newest first).
for (DeferredAction* action = actions_;
action != NULL;
action = action->next()) {
if (action->Mentions(reg)) {
switch (action->type()) {
case ActionNode::SET_REGISTER: {
Trace::DeferredSetRegister* psr =
static_cast<Trace::DeferredSetRegister*>(action);
if (!absolute) {
value += psr->value();
absolute = true;
}
// SET_REGISTER is currently only used for newly introduced loop
// counters. They can have a significant previous value if they
// occour in a loop. TODO(lrn): Propagate this information, so
// we can set undo_action to IGNORE if we know there is no value to
// restore.
undo_action = RESTORE;
ASSERT_EQ(store_position, -1);
ASSERT(!clear);
break;
}
case ActionNode::INCREMENT_REGISTER:
if (!absolute) {
value++;
}
ASSERT_EQ(store_position, -1);
ASSERT(!clear);
undo_action = RESTORE;
break;
case ActionNode::STORE_POSITION: {
Trace::DeferredCapture* pc =
static_cast<Trace::DeferredCapture*>(action);
if (!clear && store_position == -1) {
store_position = pc->cp_offset();
}
// For captures we know that stores and clears alternate.
// Other register, are never cleared, and if the occur
// inside a loop, they might be assigned more than once.
if (reg <= 1) {
// Registers zero and one, aka "capture zero", is
// always set correctly if we succeed. There is no
// need to undo a setting on backtrack, because we
// will set it again or fail.
undo_action = IGNORE;
} else {
undo_action = pc->is_capture() ? CLEAR : RESTORE;
}
ASSERT(!absolute);
ASSERT_EQ(value, 0);
break;
}
case ActionNode::CLEAR_CAPTURES: {
// Since we're scanning in reverse order, if we've already
// set the position we have to ignore historically earlier
// clearing operations.
if (store_position == -1) {
clear = true;
}
undo_action = RESTORE;
ASSERT(!absolute);
ASSERT_EQ(value, 0);
break;
}
default:
UNREACHABLE();
break;
}
}
}
// Prepare for the undo-action (e.g., push if it's going to be popped).
if (undo_action == RESTORE) {
pushes++;
RegExpMacroAssembler::StackCheckFlag stack_check =
RegExpMacroAssembler::kNoStackLimitCheck;
if (pushes == push_limit) {
stack_check = RegExpMacroAssembler::kCheckStackLimit;
pushes = 0;
}
assembler->PushRegister(reg, stack_check);
registers_to_pop->Set(reg);
} else if (undo_action == CLEAR) {
registers_to_clear->Set(reg);
}
// Perform the chronologically last action (or accumulated increment)
// for the register.
if (store_position != -1) {
assembler->WriteCurrentPositionToRegister(reg, store_position);
} else if (clear) {
assembler->ClearRegisters(reg, reg);
} else if (absolute) {
assembler->SetRegister(reg, value);
} else if (value != 0) {
assembler->AdvanceRegister(reg, value);
}
}
}
// This is called as we come into a loop choice node and some other tricky
// nodes. It normalizes the state of the code generator to ensure we can
// generate generic code.
void Trace::Flush(RegExpCompiler* compiler, RegExpNode* successor) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
ASSERT(!is_trivial());
if (actions_ == NULL && backtrack() == NULL) {
// Here we just have some deferred cp advances to fix and we are back to
// a normal situation. We may also have to forget some information gained
// through a quick check that was already performed.
if (cp_offset_ != 0) assembler->AdvanceCurrentPosition(cp_offset_);
// Create a new trivial state and generate the node with that.
Trace new_state;
successor->Emit(compiler, &new_state);
return;
}
// Generate deferred actions here along with code to undo them again.
OutSet affected_registers;
if (backtrack() != NULL) {
// Here we have a concrete backtrack location. These are set up by choice
// nodes and so they indicate that we have a deferred save of the current
// position which we may need to emit here.
assembler->PushCurrentPosition();
}
int max_register = FindAffectedRegisters(&affected_registers);
OutSet registers_to_pop;
OutSet registers_to_clear;
PerformDeferredActions(assembler,
max_register,
affected_registers,
&registers_to_pop,
&registers_to_clear);
if (cp_offset_ != 0) {
assembler->AdvanceCurrentPosition(cp_offset_);
}
// Create a new trivial state and generate the node with that.
Label undo;
assembler->PushBacktrack(&undo);
Trace new_state;
successor->Emit(compiler, &new_state);
// On backtrack we need to restore state.
assembler->Bind(&undo);
RestoreAffectedRegisters(assembler,
max_register,
registers_to_pop,
registers_to_clear);
if (backtrack() == NULL) {
assembler->Backtrack();
} else {
assembler->PopCurrentPosition();
assembler->GoTo(backtrack());
}
}
void NegativeSubmatchSuccess::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
// Omit flushing the trace. We discard the entire stack frame anyway.
if (!label()->is_bound()) {
// We are completely independent of the trace, since we ignore it,
// so this code can be used as the generic version.
assembler->Bind(label());
}
// Throw away everything on the backtrack stack since the start
// of the negative submatch and restore the character position.
assembler->ReadCurrentPositionFromRegister(current_position_register_);
assembler->ReadStackPointerFromRegister(stack_pointer_register_);
if (clear_capture_count_ > 0) {
// Clear any captures that might have been performed during the success
// of the body of the negative look-ahead.
int clear_capture_end = clear_capture_start_ + clear_capture_count_ - 1;
assembler->ClearRegisters(clear_capture_start_, clear_capture_end);
}
// Now that we have unwound the stack we find at the top of the stack the
// backtrack that the BeginSubmatch node got.
assembler->Backtrack();
}
void EndNode::Emit(RegExpCompiler* compiler, Trace* trace) {
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
RegExpMacroAssembler* assembler = compiler->macro_assembler();
if (!label()->is_bound()) {
assembler->Bind(label());
}
switch (action_) {
case ACCEPT:
assembler->Succeed();
return;
case BACKTRACK:
assembler->GoTo(trace->backtrack());
return;
case NEGATIVE_SUBMATCH_SUCCESS:
// This case is handled in a different virtual method.
UNREACHABLE();
}
UNIMPLEMENTED();
}
void GuardedAlternative::AddGuard(Guard* guard) {
if (guards_ == NULL)
guards_ = new ZoneList<Guard*>(1);
guards_->Add(guard);
}
ActionNode* ActionNode::SetRegister(int reg,
int val,
RegExpNode* on_success) {
ActionNode* result = new ActionNode(SET_REGISTER, on_success);
result->data_.u_store_register.reg = reg;
result->data_.u_store_register.value = val;
return result;
}
ActionNode* ActionNode::IncrementRegister(int reg, RegExpNode* on_success) {
ActionNode* result = new ActionNode(INCREMENT_REGISTER, on_success);
result->data_.u_increment_register.reg = reg;
return result;
}
ActionNode* ActionNode::StorePosition(int reg,
bool is_capture,
RegExpNode* on_success) {
ActionNode* result = new ActionNode(STORE_POSITION, on_success);
result->data_.u_position_register.reg = reg;
result->data_.u_position_register.is_capture = is_capture;
return result;
}
ActionNode* ActionNode::ClearCaptures(Interval range,
RegExpNode* on_success) {
ActionNode* result = new ActionNode(CLEAR_CAPTURES, on_success);
result->data_.u_clear_captures.range_from = range.from();
result->data_.u_clear_captures.range_to = range.to();
return result;
}
ActionNode* ActionNode::BeginSubmatch(int stack_reg,
int position_reg,
RegExpNode* on_success) {
ActionNode* result = new ActionNode(BEGIN_SUBMATCH, on_success);
result->data_.u_submatch.stack_pointer_register = stack_reg;
result->data_.u_submatch.current_position_register = position_reg;
return result;
}
ActionNode* ActionNode::PositiveSubmatchSuccess(int stack_reg,
int position_reg,
int clear_register_count,
int clear_register_from,
RegExpNode* on_success) {
ActionNode* result = new ActionNode(POSITIVE_SUBMATCH_SUCCESS, on_success);
result->data_.u_submatch.stack_pointer_register = stack_reg;
result->data_.u_submatch.current_position_register = position_reg;
result->data_.u_submatch.clear_register_count = clear_register_count;
result->data_.u_submatch.clear_register_from = clear_register_from;
return result;
}
ActionNode* ActionNode::EmptyMatchCheck(int start_register,
int repetition_register,
int repetition_limit,
RegExpNode* on_success) {
ActionNode* result = new ActionNode(EMPTY_MATCH_CHECK, on_success);
result->data_.u_empty_match_check.start_register = start_register;
result->data_.u_empty_match_check.repetition_register = repetition_register;
result->data_.u_empty_match_check.repetition_limit = repetition_limit;
return result;
}
#define DEFINE_ACCEPT(Type) \
void Type##Node::Accept(NodeVisitor* visitor) { \
visitor->Visit##Type(this); \
}
FOR_EACH_NODE_TYPE(DEFINE_ACCEPT)
#undef DEFINE_ACCEPT
void LoopChoiceNode::Accept(NodeVisitor* visitor) {
visitor->VisitLoopChoice(this);
}
// -------------------------------------------------------------------
// Emit code.
void ChoiceNode::GenerateGuard(RegExpMacroAssembler* macro_assembler,
Guard* guard,
Trace* trace) {
switch (guard->op()) {
case Guard::LT:
ASSERT(!trace->mentions_reg(guard->reg()));
macro_assembler->IfRegisterGE(guard->reg(),
guard->value(),
trace->backtrack());
break;
case Guard::GEQ:
ASSERT(!trace->mentions_reg(guard->reg()));
macro_assembler->IfRegisterLT(guard->reg(),
guard->value(),
trace->backtrack());
break;
}
}
// Returns the number of characters in the equivalence class, omitting those
// that cannot occur in the source string because it is ASCII.
static int GetCaseIndependentLetters(Isolate* isolate,
uc16 character,
bool ascii_subject,
unibrow::uchar* letters) {
int length =
isolate->jsregexp_uncanonicalize()->get(character, '\0', letters);
// Unibrow returns 0 or 1 for characters where case independence is
// trivial.
if (length == 0) {
letters[0] = character;
length = 1;
}
if (!ascii_subject || character <= String::kMaxAsciiCharCode) {
return length;
}
// The standard requires that non-ASCII characters cannot have ASCII
// character codes in their equivalence class.
return 0;
}
static inline bool EmitSimpleCharacter(Isolate* isolate,
RegExpCompiler* compiler,
uc16 c,
Label* on_failure,
int cp_offset,
bool check,
bool preloaded) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
bool bound_checked = false;
if (!preloaded) {
assembler->LoadCurrentCharacter(
cp_offset,
on_failure,
check);
bound_checked = true;
}
assembler->CheckNotCharacter(c, on_failure);
return bound_checked;
}
// Only emits non-letters (things that don't have case). Only used for case
// independent matches.
static inline bool EmitAtomNonLetter(Isolate* isolate,
RegExpCompiler* compiler,
uc16 c,
Label* on_failure,
int cp_offset,
bool check,
bool preloaded) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
bool ascii = compiler->ascii();
unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
int length = GetCaseIndependentLetters(isolate, c, ascii, chars);
if (length < 1) {
// This can't match. Must be an ASCII subject and a non-ASCII character.
// We do not need to do anything since the ASCII pass already handled this.
return false; // Bounds not checked.
}
bool checked = false;
// We handle the length > 1 case in a later pass.
if (length == 1) {
if (ascii && c > String::kMaxAsciiCharCodeU) {
// Can't match - see above.
return false; // Bounds not checked.
}
if (!preloaded) {
macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
checked = check;
}
macro_assembler->CheckNotCharacter(c, on_failure);
}
return checked;
}
static bool ShortCutEmitCharacterPair(RegExpMacroAssembler* macro_assembler,
bool ascii,
uc16 c1,
uc16 c2,
Label* on_failure) {
uc16 char_mask;
if (ascii) {
char_mask = String::kMaxAsciiCharCode;
} else {
char_mask = String::kMaxUC16CharCode;
}
uc16 exor = c1 ^ c2;
// Check whether exor has only one bit set.
if (((exor - 1) & exor) == 0) {
// If c1 and c2 differ only by one bit.
// Ecma262UnCanonicalize always gives the highest number last.
ASSERT(c2 > c1);
uc16 mask = char_mask ^ exor;
macro_assembler->CheckNotCharacterAfterAnd(c1, mask, on_failure);
return true;
}
ASSERT(c2 > c1);
uc16 diff = c2 - c1;
if (((diff - 1) & diff) == 0 && c1 >= diff) {
// If the characters differ by 2^n but don't differ by one bit then
// subtract the difference from the found character, then do the or
// trick. We avoid the theoretical case where negative numbers are
// involved in order to simplify code generation.
uc16 mask = char_mask ^ diff;
macro_assembler->CheckNotCharacterAfterMinusAnd(c1 - diff,
diff,
mask,
on_failure);
return true;
}
return false;
}
typedef bool EmitCharacterFunction(Isolate* isolate,
RegExpCompiler* compiler,
uc16 c,
Label* on_failure,
int cp_offset,
bool check,
bool preloaded);
// Only emits letters (things that have case). Only used for case independent
// matches.
static inline bool EmitAtomLetter(Isolate* isolate,
RegExpCompiler* compiler,
uc16 c,
Label* on_failure,
int cp_offset,
bool check,
bool preloaded) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
bool ascii = compiler->ascii();
unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
int length = GetCaseIndependentLetters(isolate, c, ascii, chars);
if (length <= 1) return false;
// We may not need to check against the end of the input string
// if this character lies before a character that matched.
if (!preloaded) {
macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check);
}
Label ok;
ASSERT(unibrow::Ecma262UnCanonicalize::kMaxWidth == 4);
switch (length) {
case 2: {
if (ShortCutEmitCharacterPair(macro_assembler,
ascii,
chars[0],
chars[1],
on_failure)) {
} else {
macro_assembler->CheckCharacter(chars[0], &ok);
macro_assembler->CheckNotCharacter(chars[1], on_failure);
macro_assembler->Bind(&ok);
}
break;
}
case 4:
macro_assembler->CheckCharacter(chars[3], &ok);
// Fall through!
case 3:
macro_assembler->CheckCharacter(chars[0], &ok);
macro_assembler->CheckCharacter(chars[1], &ok);
macro_assembler->CheckNotCharacter(chars[2], on_failure);
macro_assembler->Bind(&ok);
break;
default:
UNREACHABLE();
break;
}
return true;
}
static void EmitCharClass(RegExpMacroAssembler* macro_assembler,
RegExpCharacterClass* cc,
bool ascii,
Label* on_failure,
int cp_offset,
bool check_offset,
bool preloaded) {
ZoneList<CharacterRange>* ranges = cc->ranges();
int max_char;
if (ascii) {
max_char = String::kMaxAsciiCharCode;
} else {
max_char = String::kMaxUC16CharCode;
}
Label success;
Label* char_is_in_class =
cc->is_negated() ? on_failure : &success;
int range_count = ranges->length();
int last_valid_range = range_count - 1;
while (last_valid_range >= 0) {
CharacterRange& range = ranges->at(last_valid_range);
if (range.from() <= max_char) {
break;
}
last_valid_range--;
}
if (last_valid_range < 0) {
if (!cc->is_negated()) {
// TODO(plesner): We can remove this when the node level does our
// ASCII optimizations for us.
macro_assembler->GoTo(on_failure);
}
if (check_offset) {
macro_assembler->CheckPosition(cp_offset, on_failure);
}
return;
}
if (last_valid_range == 0 &&
!cc->is_negated() &&
ranges->at(0).IsEverything(max_char)) {
// This is a common case hit by non-anchored expressions.
if (check_offset) {
macro_assembler->CheckPosition(cp_offset, on_failure);
}
return;
}
if (!preloaded) {
macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check_offset);
}
if (cc->is_standard() &&
macro_assembler->CheckSpecialCharacterClass(cc->standard_type(),
on_failure)) {
return;
}
for (int i = 0; i < last_valid_range; i++) {
CharacterRange& range = ranges->at(i);
Label next_range;
uc16 from = range.from();
uc16 to = range.to();
if (from > max_char) {
continue;
}
if (to > max_char) to = max_char;
if (to == from) {
macro_assembler->CheckCharacter(to, char_is_in_class);
} else {
if (from != 0) {
macro_assembler->CheckCharacterLT(from, &next_range);
}
if (to != max_char) {
macro_assembler->CheckCharacterLT(to + 1, char_is_in_class);
} else {
macro_assembler->GoTo(char_is_in_class);
}
}
macro_assembler->Bind(&next_range);
}
CharacterRange& range = ranges->at(last_valid_range);
uc16 from = range.from();
uc16 to = range.to();
if (to > max_char) to = max_char;
ASSERT(to >= from);
if (to == from) {
if (cc->is_negated()) {
macro_assembler->CheckCharacter(to, on_failure);
} else {
macro_assembler->CheckNotCharacter(to, on_failure);
}
} else {
if (from != 0) {
if (cc->is_negated()) {
macro_assembler->CheckCharacterLT(from, &success);
} else {
macro_assembler->CheckCharacterLT(from, on_failure);
}
}
if (to != String::kMaxUC16CharCode) {
if (cc->is_negated()) {
macro_assembler->CheckCharacterLT(to + 1, on_failure);
} else {
macro_assembler->CheckCharacterGT(to, on_failure);
}
} else {
if (cc->is_negated()) {
macro_assembler->GoTo(on_failure);
}
}
}
macro_assembler->Bind(&success);
}
RegExpNode::~RegExpNode() {
}
RegExpNode::LimitResult RegExpNode::LimitVersions(RegExpCompiler* compiler,
Trace* trace) {
// If we are generating a greedy loop then don't stop and don't reuse code.
if (trace->stop_node() != NULL) {
return CONTINUE;
}
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
if (trace->is_trivial()) {
if (label_.is_bound()) {
// We are being asked to generate a generic version, but that's already
// been done so just go to it.
macro_assembler->GoTo(&label_);
return DONE;
}
if (compiler->recursion_depth() >= RegExpCompiler::kMaxRecursion) {
// To avoid too deep recursion we push the node to the work queue and just
// generate a goto here.
compiler->AddWork(this);
macro_assembler->GoTo(&label_);
return DONE;
}
// Generate generic version of the node and bind the label for later use.
macro_assembler->Bind(&label_);
return CONTINUE;
}
// We are being asked to make a non-generic version. Keep track of how many
// non-generic versions we generate so as not to overdo it.
trace_count_++;
if (FLAG_regexp_optimization &&
trace_count_ < kMaxCopiesCodeGenerated &&
compiler->recursion_depth() <= RegExpCompiler::kMaxRecursion) {
return CONTINUE;
}
// If we get here code has been generated for this node too many times or
// recursion is too deep. Time to switch to a generic version. The code for
// generic versions above can handle deep recursion properly.
trace->Flush(compiler, this);
return DONE;
}
int ActionNode::EatsAtLeast(int still_to_find,
int recursion_depth,
bool not_at_start) {
if (recursion_depth > RegExpCompiler::kMaxRecursion) return 0;
if (type_ == POSITIVE_SUBMATCH_SUCCESS) return 0; // Rewinds input!
return on_success()->EatsAtLeast(still_to_find,
recursion_depth + 1,
not_at_start);
}
int AssertionNode::EatsAtLeast(int still_to_find,
int recursion_depth,
bool not_at_start) {
if (recursion_depth > RegExpCompiler::kMaxRecursion) return 0;
// If we know we are not at the start and we are asked "how many characters
// will you match if you succeed?" then we can answer anything since false
// implies false. So lets just return the max answer (still_to_find) since
// that won't prevent us from preloading a lot of characters for the other
// branches in the node graph.
if (type() == AT_START && not_at_start) return still_to_find;
return on_success()->EatsAtLeast(still_to_find,
recursion_depth + 1,
not_at_start);
}
int BackReferenceNode::EatsAtLeast(int still_to_find,
int recursion_depth,
bool not_at_start) {
if (recursion_depth > RegExpCompiler::kMaxRecursion) return 0;
return on_success()->EatsAtLeast(still_to_find,
recursion_depth + 1,
not_at_start);
}
int TextNode::EatsAtLeast(int still_to_find,
int recursion_depth,
bool not_at_start) {
int answer = Length();
if (answer >= still_to_find) return answer;
if (recursion_depth > RegExpCompiler::kMaxRecursion) return answer;
// We are not at start after this node so we set the last argument to 'true'.
return answer + on_success()->EatsAtLeast(still_to_find - answer,
recursion_depth + 1,
true);
}
int NegativeLookaheadChoiceNode::EatsAtLeast(int still_to_find,
int recursion_depth,
bool not_at_start) {
if (recursion_depth > RegExpCompiler::kMaxRecursion) return 0;
// Alternative 0 is the negative lookahead, alternative 1 is what comes
// afterwards.
RegExpNode* node = alternatives_->at(1).node();
return node->EatsAtLeast(still_to_find, recursion_depth + 1, not_at_start);
}
void NegativeLookaheadChoiceNode::GetQuickCheckDetails(
QuickCheckDetails* details,
RegExpCompiler* compiler,
int filled_in,
bool not_at_start) {
// Alternative 0 is the negative lookahead, alternative 1 is what comes
// afterwards.
RegExpNode* node = alternatives_->at(1).node();
return node->GetQuickCheckDetails(details, compiler, filled_in, not_at_start);
}
int ChoiceNode::EatsAtLeastHelper(int still_to_find,
int recursion_depth,
RegExpNode* ignore_this_node,
bool not_at_start) {
if (recursion_depth > RegExpCompiler::kMaxRecursion) return 0;
int min = 100;
int choice_count = alternatives_->length();
for (int i = 0; i < choice_count; i++) {
RegExpNode* node = alternatives_->at(i).node();
if (node == ignore_this_node) continue;
int node_eats_at_least = node->EatsAtLeast(still_to_find,
recursion_depth + 1,
not_at_start);
if (node_eats_at_least < min) min = node_eats_at_least;
}
return min;
}
int LoopChoiceNode::EatsAtLeast(int still_to_find,
int recursion_depth,
bool not_at_start) {
return EatsAtLeastHelper(still_to_find,
recursion_depth,
loop_node_,
not_at_start);
}
int ChoiceNode::EatsAtLeast(int still_to_find,
int recursion_depth,
bool not_at_start) {
return EatsAtLeastHelper(still_to_find,
recursion_depth,
NULL,
not_at_start);
}
// Takes the left-most 1-bit and smears it out, setting all bits to its right.
static inline uint32_t SmearBitsRight(uint32_t v) {
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
v |= v >> 8;
v |= v >> 16;
return v;
}
bool QuickCheckDetails::Rationalize(bool asc) {
bool found_useful_op = false;
uint32_t char_mask;
if (asc) {
char_mask = String::kMaxAsciiCharCode;
} else {
char_mask = String::kMaxUC16CharCode;
}
mask_ = 0;
value_ = 0;
int char_shift = 0;
for (int i = 0; i < characters_; i++) {
Position* pos = &positions_[i];
if ((pos->mask & String::kMaxAsciiCharCode) != 0) {
found_useful_op = true;
}
mask_ |= (pos->mask & char_mask) << char_shift;
value_ |= (pos->value & char_mask) << char_shift;
char_shift += asc ? 8 : 16;
}
return found_useful_op;
}
bool RegExpNode::EmitQuickCheck(RegExpCompiler* compiler,
Trace* trace,
bool preload_has_checked_bounds,
Label* on_possible_success,
QuickCheckDetails* details,
bool fall_through_on_failure) {
if (details->characters() == 0) return false;
GetQuickCheckDetails(details, compiler, 0, trace->at_start() == Trace::FALSE);
if (details->cannot_match()) return false;
if (!details->Rationalize(compiler->ascii())) return false;
ASSERT(details->characters() == 1 ||
compiler->macro_assembler()->CanReadUnaligned());
uint32_t mask = details->mask();
uint32_t value = details->value();
RegExpMacroAssembler* assembler = compiler->macro_assembler();
if (trace->characters_preloaded() != details->characters()) {
assembler->LoadCurrentCharacter(trace->cp_offset(),
trace->backtrack(),
!preload_has_checked_bounds,
details->characters());
}
bool need_mask = true;
if (details->characters() == 1) {
// If number of characters preloaded is 1 then we used a byte or 16 bit
// load so the value is already masked down.
uint32_t char_mask;
if (compiler->ascii()) {
char_mask = String::kMaxAsciiCharCode;
} else {
char_mask = String::kMaxUC16CharCode;
}
if ((mask & char_mask) == char_mask) need_mask = false;
mask &= char_mask;
} else {
// For 2-character preloads in ASCII mode or 1-character preloads in
// TWO_BYTE mode we also use a 16 bit load with zero extend.
if (details->characters() == 2 && compiler->ascii()) {
if ((mask & 0x7f7f) == 0x7f7f) need_mask = false;
} else if (details->characters() == 1 && !compiler->ascii()) {
if ((mask & 0xffff) == 0xffff) need_mask = false;
} else {
if (mask == 0xffffffff) need_mask = false;
}
}
if (fall_through_on_failure) {
if (need_mask) {
assembler->CheckCharacterAfterAnd(value, mask, on_possible_success);
} else {
assembler->CheckCharacter(value, on_possible_success);
}
} else {
if (need_mask) {
assembler->CheckNotCharacterAfterAnd(value, mask, trace->backtrack());
} else {
assembler->CheckNotCharacter(value, trace->backtrack());
}
}
return true;
}
// Here is the meat of GetQuickCheckDetails (see also the comment on the
// super-class in the .h file).
//
// We iterate along the text object, building up for each character a
// mask and value that can be used to test for a quick failure to match.
// The masks and values for the positions will be combined into a single
// machine word for the current character width in order to be used in
// generating a quick check.
void TextNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
int characters_filled_in,
bool not_at_start) {
Isolate* isolate = Isolate::Current();
ASSERT(characters_filled_in < details->characters());
int characters = details->characters();
int char_mask;
if (compiler->ascii()) {
char_mask = String::kMaxAsciiCharCode;
} else {
char_mask = String::kMaxUC16CharCode;
}
for (int k = 0; k < elms_->length(); k++) {
TextElement elm = elms_->at(k);
if (elm.type == TextElement::ATOM) {
Vector<const uc16> quarks = elm.data.u_atom->data();
for (int i = 0; i < characters && i < quarks.length(); i++) {
QuickCheckDetails::Position* pos =
details->positions(characters_filled_in);
uc16 c = quarks[i];
if (c > char_mask) {
// If we expect a non-ASCII character from an ASCII string,
// there is no way we can match. Not even case independent
// matching can turn an ASCII character into non-ASCII or
// vice versa.
details->set_cannot_match();
pos->determines_perfectly = false;
return;
}
if (compiler->ignore_case()) {
unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
int length = GetCaseIndependentLetters(isolate, c, compiler->ascii(),
chars);
ASSERT(length != 0); // Can only happen if c > char_mask (see above).
if (length == 1) {
// This letter has no case equivalents, so it's nice and simple
// and the mask-compare will determine definitely whether we have
// a match at this character position.
pos->mask = char_mask;
pos->value = c;
pos->determines_perfectly = true;
} else {
uint32_t common_bits = char_mask;
uint32_t bits = chars[0];
for (int j = 1; j < length; j++) {
uint32_t differing_bits = ((chars[j] & common_bits) ^ bits);
common_bits ^= differing_bits;
bits &= common_bits;
}
// If length is 2 and common bits has only one zero in it then
// our mask and compare instruction will determine definitely
// whether we have a match at this character position. Otherwise
// it can only be an approximate check.
uint32_t one_zero = (common_bits | ~char_mask);
if (length == 2 && ((~one_zero) & ((~one_zero) - 1)) == 0) {
pos->determines_perfectly = true;
}
pos->mask = common_bits;
pos->value = bits;
}
} else {
// Don't ignore case. Nice simple case where the mask-compare will
// determine definitely whether we have a match at this character
// position.
pos->mask = char_mask;
pos->value = c;
pos->determines_perfectly = true;
}
characters_filled_in++;
ASSERT(characters_filled_in <= details->characters());
if (characters_filled_in == details->characters()) {
return;
}
}
} else {
QuickCheckDetails::Position* pos =
details->positions(characters_filled_in);
RegExpCharacterClass* tree = elm.data.u_char_class;
ZoneList<CharacterRange>* ranges = tree->ranges();
if (tree->is_negated()) {
// A quick check uses multi-character mask and compare. There is no
// useful way to incorporate a negative char class into this scheme
// so we just conservatively create a mask and value that will always
// succeed.
pos->mask = 0;
pos->value = 0;
} else {
int first_range = 0;
while (ranges->at(first_range).from() > char_mask) {
first_range++;
if (first_range == ranges->length()) {
details->set_cannot_match();
pos->determines_perfectly = false;
return;
}
}
CharacterRange range = ranges->at(first_range);
uc16 from = range.from();
uc16 to = range.to();
if (to > char_mask) {
to = char_mask;
}
uint32_t differing_bits = (from ^ to);
// A mask and compare is only perfect if the differing bits form a
// number like 00011111 with one single block of trailing 1s.
if ((differing_bits & (differing_bits + 1)) == 0 &&
from + differing_bits == to) {
pos->determines_perfectly = true;
}
uint32_t common_bits = ~SmearBitsRight(differing_bits);
uint32_t bits = (from & common_bits);
for (int i = first_range + 1; i < ranges->length(); i++) {
CharacterRange range = ranges->at(i);
uc16 from = range.from();
uc16 to = range.to();
if (from > char_mask) continue;
if (to > char_mask) to = char_mask;
// Here we are combining more ranges into the mask and compare
// value. With each new range the mask becomes more sparse and
// so the chances of a false positive rise. A character class
// with multiple ranges is assumed never to be equivalent to a
// mask and compare operation.
pos->determines_perfectly = false;
uint32_t new_common_bits = (from ^ to);
new_common_bits = ~SmearBitsRight(new_common_bits);
common_bits &= new_common_bits;
bits &= new_common_bits;
uint32_t differing_bits = (from & common_bits) ^ bits;
common_bits ^= differing_bits;
bits &= common_bits;
}
pos->mask = common_bits;
pos->value = bits;
}
characters_filled_in++;
ASSERT(characters_filled_in <= details->characters());
if (characters_filled_in == details->characters()) {
return;
}
}
}
ASSERT(characters_filled_in != details->characters());
on_success()-> GetQuickCheckDetails(details,
compiler,
characters_filled_in,
true);
}
void QuickCheckDetails::Clear() {
for (int i = 0; i < characters_; i++) {
positions_[i].mask = 0;
positions_[i].value = 0;
positions_[i].determines_perfectly = false;
}
characters_ = 0;
}
void QuickCheckDetails::Advance(int by, bool ascii) {
ASSERT(by >= 0);
if (by >= characters_) {
Clear();
return;
}
for (int i = 0; i < characters_ - by; i++) {
positions_[i] = positions_[by + i];
}
for (int i = characters_ - by; i < characters_; i++) {
positions_[i].mask = 0;
positions_[i].value = 0;
positions_[i].determines_perfectly = false;
}
characters_ -= by;
// We could change mask_ and value_ here but we would never advance unless
// they had already been used in a check and they won't be used again because
// it would gain us nothing. So there's no point.
}
void QuickCheckDetails::Merge(QuickCheckDetails* other, int from_index) {
ASSERT(characters_ == other->characters_);
if (other->cannot_match_) {
return;
}
if (cannot_match_) {
*this = *other;
return;
}
for (int i = from_index; i < characters_; i++) {
QuickCheckDetails::Position* pos = positions(i);
QuickCheckDetails::Position* other_pos = other->positions(i);
if (pos->mask != other_pos->mask ||
pos->value != other_pos->value ||
!other_pos->determines_perfectly) {
// Our mask-compare operation will be approximate unless we have the
// exact same operation on both sides of the alternation.
pos->determines_perfectly = false;
}
pos->mask &= other_pos->mask;
pos->value &= pos->mask;
other_pos->value &= pos->mask;
uc16 differing_bits = (pos->value ^ other_pos->value);
pos->mask &= ~differing_bits;
pos->value &= pos->mask;
}
}
class VisitMarker {
public:
explicit VisitMarker(NodeInfo* info) : info_(info) {
ASSERT(!info->visited);
info->visited = true;
}
~VisitMarker() {
info_->visited = false;
}
private:
NodeInfo* info_;
};
void LoopChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
int characters_filled_in,
bool not_at_start) {
if (body_can_be_zero_length_ || info()->visited) return;
VisitMarker marker(info());
return ChoiceNode::GetQuickCheckDetails(details,
compiler,
characters_filled_in,
not_at_start);
}
void ChoiceNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
int characters_filled_in,
bool not_at_start) {
not_at_start = (not_at_start || not_at_start_);
int choice_count = alternatives_->length();
ASSERT(choice_count > 0);
alternatives_->at(0).node()->GetQuickCheckDetails(details,
compiler,
characters_filled_in,
not_at_start);
for (int i = 1; i < choice_count; i++) {
QuickCheckDetails new_details(details->characters());
RegExpNode* node = alternatives_->at(i).node();
node->GetQuickCheckDetails(&new_details, compiler,
characters_filled_in,
not_at_start);
// Here we merge the quick match details of the two branches.
details->Merge(&new_details, characters_filled_in);
}
}
// Check for [0-9A-Z_a-z].
static void EmitWordCheck(RegExpMacroAssembler* assembler,
Label* word,
Label* non_word,
bool fall_through_on_word) {
if (assembler->CheckSpecialCharacterClass(
fall_through_on_word ? 'w' : 'W',
fall_through_on_word ? non_word : word)) {
// Optimized implementation available.
return;
}
assembler->CheckCharacterGT('z', non_word);
assembler->CheckCharacterLT('0', non_word);
assembler->CheckCharacterGT('a' - 1, word);
assembler->CheckCharacterLT('9' + 1, word);
assembler->CheckCharacterLT('A', non_word);
assembler->CheckCharacterLT('Z' + 1, word);
if (fall_through_on_word) {
assembler->CheckNotCharacter('_', non_word);
} else {
assembler->CheckCharacter('_', word);
}
}
// Emit the code to check for a ^ in multiline mode (1-character lookbehind
// that matches newline or the start of input).
static void EmitHat(RegExpCompiler* compiler,
RegExpNode* on_success,
Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
// We will be loading the previous character into the current character
// register.
Trace new_trace(*trace);
new_trace.InvalidateCurrentCharacter();
Label ok;
if (new_trace.cp_offset() == 0) {
// The start of input counts as a newline in this context, so skip to
// ok if we are at the start.
assembler->CheckAtStart(&ok);
}
// We already checked that we are not at the start of input so it must be
// OK to load the previous character.
assembler->LoadCurrentCharacter(new_trace.cp_offset() -1,
new_trace.backtrack(),
false);
if (!assembler->CheckSpecialCharacterClass('n',
new_trace.backtrack())) {
// Newline means \n, \r, 0x2028 or 0x2029.
if (!compiler->ascii()) {
assembler->CheckCharacterAfterAnd(0x2028, 0xfffe, &ok);
}
assembler->CheckCharacter('\n', &ok);
assembler->CheckNotCharacter('\r', new_trace.backtrack());
}
assembler->Bind(&ok);
on_success->Emit(compiler, &new_trace);
}
// Emit the code to handle \b and \B (word-boundary or non-word-boundary)
// when we know whether the next character must be a word character or not.
static void EmitHalfBoundaryCheck(AssertionNode::AssertionNodeType type,
RegExpCompiler* compiler,
RegExpNode* on_success,
Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
Label done;
Trace new_trace(*trace);
bool expect_word_character = (type == AssertionNode::AFTER_WORD_CHARACTER);
Label* on_word = expect_word_character ? &done : new_trace.backtrack();
Label* on_non_word = expect_word_character ? new_trace.backtrack() : &done;
// Check whether previous character was a word character.
switch (trace->at_start()) {
case Trace::TRUE:
if (expect_word_character) {
assembler->GoTo(on_non_word);
}
break;
case Trace::UNKNOWN:
ASSERT_EQ(0, trace->cp_offset());
assembler->CheckAtStart(on_non_word);
// Fall through.
case Trace::FALSE:
int prev_char_offset = trace->cp_offset() - 1;
assembler->LoadCurrentCharacter(prev_char_offset, NULL, false, 1);
EmitWordCheck(assembler, on_word, on_non_word, expect_word_character);
// We may or may not have loaded the previous character.
new_trace.InvalidateCurrentCharacter();
}
assembler->Bind(&done);
on_success->Emit(compiler, &new_trace);
}
// Emit the code to handle \b and \B (word-boundary or non-word-boundary).
static void EmitBoundaryCheck(AssertionNode::AssertionNodeType type,
RegExpCompiler* compiler,
RegExpNode* on_success,
Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
Label before_non_word;
Label before_word;
if (trace->characters_preloaded() != 1) {
assembler->LoadCurrentCharacter(trace->cp_offset(), &before_non_word);
}
// Fall through on non-word.
EmitWordCheck(assembler, &before_word, &before_non_word, false);
// We will be loading the previous character into the current character
// register.
Trace new_trace(*trace);
new_trace.InvalidateCurrentCharacter();
Label ok;
Label* boundary;
Label* not_boundary;
if (type == AssertionNode::AT_BOUNDARY) {
boundary = &ok;
not_boundary = new_trace.backtrack();
} else {
not_boundary = &ok;
boundary = new_trace.backtrack();
}
// Next character is not a word character.
assembler->Bind(&before_non_word);
if (new_trace.cp_offset() == 0) {
// The start of input counts as a non-word character, so the question is
// decided if we are at the start.
assembler->CheckAtStart(not_boundary);
}
// We already checked that we are not at the start of input so it must be
// OK to load the previous character.
assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1,
&ok, // Unused dummy label in this call.
false);
// Fall through on non-word.
EmitWordCheck(assembler, boundary, not_boundary, false);
assembler->GoTo(not_boundary);
// Next character is a word character.
assembler->Bind(&before_word);
if (new_trace.cp_offset() == 0) {
// The start of input counts as a non-word character, so the question is
// decided if we are at the start.
assembler->CheckAtStart(boundary);
}
// We already checked that we are not at the start of input so it must be
// OK to load the previous character.
assembler->LoadCurrentCharacter(new_trace.cp_offset() - 1,
&ok, // Unused dummy label in this call.
false);
bool fall_through_on_word = (type == AssertionNode::AT_NON_BOUNDARY);
EmitWordCheck(assembler, not_boundary, boundary, fall_through_on_word);
assembler->Bind(&ok);
on_success->Emit(compiler, &new_trace);
}
void AssertionNode::GetQuickCheckDetails(QuickCheckDetails* details,
RegExpCompiler* compiler,
int filled_in,
bool not_at_start) {
if (type_ == AT_START && not_at_start) {
details->set_cannot_match();
return;
}
return on_success()->GetQuickCheckDetails(details,
compiler,
filled_in,
not_at_start);
}
void AssertionNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
switch (type_) {
case AT_END: {
Label ok;
assembler->CheckPosition(trace->cp_offset(), &ok);
assembler->GoTo(trace->backtrack());
assembler->Bind(&ok);
break;
}
case AT_START: {
if (trace->at_start() == Trace::FALSE) {
assembler->GoTo(trace->backtrack());
return;
}
if (trace->at_start() == Trace::UNKNOWN) {
assembler->CheckNotAtStart(trace->backtrack());
Trace at_start_trace = *trace;
at_start_trace.set_at_start(true);
on_success()->Emit(compiler, &at_start_trace);
return;
}
}
break;
case AFTER_NEWLINE:
EmitHat(compiler, on_success(), trace);
return;
case AT_BOUNDARY:
case AT_NON_BOUNDARY: {
EmitBoundaryCheck(type_, compiler, on_success(), trace);
return;
}
case AFTER_WORD_CHARACTER:
case AFTER_NONWORD_CHARACTER: {
EmitHalfBoundaryCheck(type_, compiler, on_success(), trace);
}
}
on_success()->Emit(compiler, trace);
}
static bool DeterminedAlready(QuickCheckDetails* quick_check, int offset) {
if (quick_check == NULL) return false;
if (offset >= quick_check->characters()) return false;
return quick_check->positions(offset)->determines_perfectly;
}
static void UpdateBoundsCheck(int index, int* checked_up_to) {
if (index > *checked_up_to) {
*checked_up_to = index;
}
}
// We call this repeatedly to generate code for each pass over the text node.
// The passes are in increasing order of difficulty because we hope one
// of the first passes will fail in which case we are saved the work of the
// later passes. for example for the case independent regexp /%[asdfghjkl]a/
// we will check the '%' in the first pass, the case independent 'a' in the
// second pass and the character class in the last pass.
//
// The passes are done from right to left, so for example to test for /bar/
// we will first test for an 'r' with offset 2, then an 'a' with offset 1
// and then a 'b' with offset 0. This means we can avoid the end-of-input
// bounds check most of the time. In the example we only need to check for
// end-of-input when loading the putative 'r'.
//
// A slight complication involves the fact that the first character may already
// be fetched into a register by the previous node. In this case we want to
// do the test for that character first. We do this in separate passes. The
// 'preloaded' argument indicates that we are doing such a 'pass'. If such a
// pass has been performed then subsequent passes will have true in
// first_element_checked to indicate that that character does not need to be
// checked again.
//
// In addition to all this we are passed a Trace, which can
// contain an AlternativeGeneration object. In this AlternativeGeneration
// object we can see details of any quick check that was already passed in
// order to get to the code we are now generating. The quick check can involve
// loading characters, which means we do not need to recheck the bounds
// up to the limit the quick check already checked. In addition the quick
// check can have involved a mask and compare operation which may simplify
// or obviate the need for further checks at some character positions.
void TextNode::TextEmitPass(RegExpCompiler* compiler,
TextEmitPassType pass,
bool preloaded,
Trace* trace,
bool first_element_checked,
int* checked_up_to) {
Isolate* isolate = Isolate::Current();
RegExpMacroAssembler* assembler = compiler->macro_assembler();
bool ascii = compiler->ascii();
Label* backtrack = trace->backtrack();
QuickCheckDetails* quick_check = trace->quick_check_performed();
int element_count = elms_->length();
for (int i = preloaded ? 0 : element_count - 1; i >= 0; i--) {
TextElement elm = elms_->at(i);
int cp_offset = trace->cp_offset() + elm.cp_offset;
if (elm.type == TextElement::ATOM) {
Vector<const uc16> quarks = elm.data.u_atom->data();
for (int j = preloaded ? 0 : quarks.length() - 1; j >= 0; j--) {
if (first_element_checked && i == 0 && j == 0) continue;
if (DeterminedAlready(quick_check, elm.cp_offset + j)) continue;
EmitCharacterFunction* emit_function = NULL;
switch (pass) {
case NON_ASCII_MATCH:
ASSERT(ascii);
if (quarks[j] > String::kMaxAsciiCharCode) {
assembler->GoTo(backtrack);
return;
}
break;
case NON_LETTER_CHARACTER_MATCH:
emit_function = &EmitAtomNonLetter;
break;
case SIMPLE_CHARACTER_MATCH:
emit_function = &EmitSimpleCharacter;
break;
case CASE_CHARACTER_MATCH:
emit_function = &EmitAtomLetter;
break;
default:
break;
}
if (emit_function != NULL) {
bool bound_checked = emit_function(isolate,
compiler,
quarks[j],
backtrack,
cp_offset + j,
*checked_up_to < cp_offset + j,
preloaded);
if (bound_checked) UpdateBoundsCheck(cp_offset + j, checked_up_to);
}
}
} else {
ASSERT_EQ(elm.type, TextElement::CHAR_CLASS);
if (pass == CHARACTER_CLASS_MATCH) {
if (first_element_checked && i == 0) continue;
if (DeterminedAlready(quick_check, elm.cp_offset)) continue;
RegExpCharacterClass* cc = elm.data.u_char_class;
EmitCharClass(assembler,
cc,
ascii,
backtrack,
cp_offset,
*checked_up_to < cp_offset,
preloaded);
UpdateBoundsCheck(cp_offset, checked_up_to);
}
}
}
}
int TextNode::Length() {
TextElement elm = elms_->last();
ASSERT(elm.cp_offset >= 0);
if (elm.type == TextElement::ATOM) {
return elm.cp_offset + elm.data.u_atom->data().length();
} else {
return elm.cp_offset + 1;
}
}
bool TextNode::SkipPass(int int_pass, bool ignore_case) {
TextEmitPassType pass = static_cast<TextEmitPassType>(int_pass);
if (ignore_case) {
return pass == SIMPLE_CHARACTER_MATCH;
} else {
return pass == NON_LETTER_CHARACTER_MATCH || pass == CASE_CHARACTER_MATCH;
}
}
// This generates the code to match a text node. A text node can contain
// straight character sequences (possibly to be matched in a case-independent
// way) and character classes. For efficiency we do not do this in a single
// pass from left to right. Instead we pass over the text node several times,
// emitting code for some character positions every time. See the comment on
// TextEmitPass for details.
void TextNode::Emit(RegExpCompiler* compiler, Trace* trace) {
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
if (trace->cp_offset() + Length() > RegExpMacroAssembler::kMaxCPOffset) {
compiler->SetRegExpTooBig();
return;
}
if (compiler->ascii()) {
int dummy = 0;
TextEmitPass(compiler, NON_ASCII_MATCH, false, trace, false, &dummy);
}
bool first_elt_done = false;
int bound_checked_to = trace->cp_offset() - 1;
bound_checked_to += trace->bound_checked_up_to();
// If a character is preloaded into the current character register then
// check that now.
if (trace->characters_preloaded() == 1) {
for (int pass = kFirstRealPass; pass <= kLastPass; pass++) {
if (!SkipPass(pass, compiler->ignore_case())) {
TextEmitPass(compiler,
static_cast<TextEmitPassType>(pass),
true,
trace,
false,
&bound_checked_to);
}
}
first_elt_done = true;
}
for (int pass = kFirstRealPass; pass <= kLastPass; pass++) {
if (!SkipPass(pass, compiler->ignore_case())) {
TextEmitPass(compiler,
static_cast<TextEmitPassType>(pass),
false,
trace,
first_elt_done,
&bound_checked_to);
}
}
Trace successor_trace(*trace);
successor_trace.set_at_start(false);
successor_trace.AdvanceCurrentPositionInTrace(Length(), compiler);
RecursionCheck rc(compiler);
on_success()->Emit(compiler, &successor_trace);
}
void Trace::InvalidateCurrentCharacter() {
characters_preloaded_ = 0;
}
void Trace::AdvanceCurrentPositionInTrace(int by, RegExpCompiler* compiler) {
ASSERT(by > 0);
// We don't have an instruction for shifting the current character register
// down or for using a shifted value for anything so lets just forget that
// we preloaded any characters into it.
characters_preloaded_ = 0;
// Adjust the offsets of the quick check performed information. This
// information is used to find out what we already determined about the
// characters by means of mask and compare.
quick_check_performed_.Advance(by, compiler->ascii());
cp_offset_ += by;
if (cp_offset_ > RegExpMacroAssembler::kMaxCPOffset) {
compiler->SetRegExpTooBig();
cp_offset_ = 0;
}
bound_checked_up_to_ = Max(0, bound_checked_up_to_ - by);
}
void TextNode::MakeCaseIndependent(bool is_ascii) {
int element_count = elms_->length();
for (int i = 0; i < element_count; i++) {
TextElement elm = elms_->at(i);
if (elm.type == TextElement::CHAR_CLASS) {
RegExpCharacterClass* cc = elm.data.u_char_class;
// None of the standard character classes is different in the case
// independent case and it slows us down if we don't know that.
if (cc->is_standard()) continue;
ZoneList<CharacterRange>* ranges = cc->ranges();
int range_count = ranges->length();
for (int j = 0; j < range_count; j++) {
ranges->at(j).AddCaseEquivalents(ranges, is_ascii);
}
}
}
}
int TextNode::GreedyLoopTextLength() {
TextElement elm = elms_->at(elms_->length() - 1);
if (elm.type == TextElement::CHAR_CLASS) {
return elm.cp_offset + 1;
} else {
return elm.cp_offset + elm.data.u_atom->data().length();
}
}
// Finds the fixed match length of a sequence of nodes that goes from
// this alternative and back to this choice node. If there are variable
// length nodes or other complications in the way then return a sentinel
// value indicating that a greedy loop cannot be constructed.
int ChoiceNode::GreedyLoopTextLengthForAlternative(
GuardedAlternative* alternative) {
int length = 0;
RegExpNode* node = alternative->node();
// Later we will generate code for all these text nodes using recursion
// so we have to limit the max number.
int recursion_depth = 0;
while (node != this) {
if (recursion_depth++ > RegExpCompiler::kMaxRecursion) {
return kNodeIsTooComplexForGreedyLoops;
}
int node_length = node->GreedyLoopTextLength();
if (node_length == kNodeIsTooComplexForGreedyLoops) {
return kNodeIsTooComplexForGreedyLoops;
}
length += node_length;
SeqRegExpNode* seq_node = static_cast<SeqRegExpNode*>(node);
node = seq_node->on_success();
}
return length;
}
void LoopChoiceNode::AddLoopAlternative(GuardedAlternative alt) {
ASSERT_EQ(loop_node_, NULL);
AddAlternative(alt);
loop_node_ = alt.node();
}
void LoopChoiceNode::AddContinueAlternative(GuardedAlternative alt) {
ASSERT_EQ(continue_node_, NULL);
AddAlternative(alt);
continue_node_ = alt.node();
}
void LoopChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
if (trace->stop_node() == this) {
int text_length =
GreedyLoopTextLengthForAlternative(&(alternatives_->at(0)));
ASSERT(text_length != kNodeIsTooComplexForGreedyLoops);
// Update the counter-based backtracking info on the stack. This is an
// optimization for greedy loops (see below).
ASSERT(trace->cp_offset() == text_length);
macro_assembler->AdvanceCurrentPosition(text_length);
macro_assembler->GoTo(trace->loop_label());
return;
}
ASSERT(trace->stop_node() == NULL);
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
ChoiceNode::Emit(compiler, trace);
}
int ChoiceNode::CalculatePreloadCharacters(RegExpCompiler* compiler,
bool not_at_start) {
int preload_characters = EatsAtLeast(4, 0, not_at_start);
if (compiler->macro_assembler()->CanReadUnaligned()) {
bool ascii = compiler->ascii();
if (ascii) {
if (preload_characters > 4) preload_characters = 4;
// We can't preload 3 characters because there is no machine instruction
// to do that. We can't just load 4 because we could be reading
// beyond the end of the string, which could cause a memory fault.
if (preload_characters == 3) preload_characters = 2;
} else {
if (preload_characters > 2) preload_characters = 2;
}
} else {
if (preload_characters > 1) preload_characters = 1;
}
return preload_characters;
}
// This class is used when generating the alternatives in a choice node. It
// records the way the alternative is being code generated.
class AlternativeGeneration: public Malloced {
public:
AlternativeGeneration()
: possible_success(),
expects_preload(false),
after(),
quick_check_details() { }
Label possible_success;
bool expects_preload;
Label after;
QuickCheckDetails quick_check_details;
};
// Creates a list of AlternativeGenerations. If the list has a reasonable
// size then it is on the stack, otherwise the excess is on the heap.
class AlternativeGenerationList {
public:
explicit AlternativeGenerationList(int count)
: alt_gens_(count) {
for (int i = 0; i < count && i < kAFew; i++) {
alt_gens_.Add(a_few_alt_gens_ + i);
}
for (int i = kAFew; i < count; i++) {
alt_gens_.Add(new AlternativeGeneration());
}
}
~AlternativeGenerationList() {
for (int i = kAFew; i < alt_gens_.length(); i++) {
delete alt_gens_[i];
alt_gens_[i] = NULL;
}
}
AlternativeGeneration* at(int i) {
return alt_gens_[i];
}
private:
static const int kAFew = 10;
ZoneList<AlternativeGeneration*> alt_gens_;
AlternativeGeneration a_few_alt_gens_[kAFew];
};
/* Code generation for choice nodes.
*
* We generate quick checks that do a mask and compare to eliminate a
* choice. If the quick check succeeds then it jumps to the continuation to
* do slow checks and check subsequent nodes. If it fails (the common case)
* it falls through to the next choice.
*
* Here is the desired flow graph. Nodes directly below each other imply
* fallthrough. Alternatives 1 and 2 have quick checks. Alternative
* 3 doesn't have a quick check so we have to call the slow check.
* Nodes are marked Qn for quick checks and Sn for slow checks. The entire
* regexp continuation is generated directly after the Sn node, up to the
* next GoTo if we decide to reuse some already generated code. Some
* nodes expect preload_characters to be preloaded into the current
* character register. R nodes do this preloading. Vertices are marked
* F for failures and S for success (possible success in the case of quick
* nodes). L, V, < and > are used as arrow heads.
*
* ----------> R
* |
* V
* Q1 -----> S1
* | S /
* F| /
* | F/
* | /
* | R
* | /
* V L
* Q2 -----> S2
* | S /
* F| /
* | F/
* | /
* | R
* | /
* V L
* S3
* |
* F|
* |
* R
* |
* backtrack V
* <----------Q4
* \ F |
* \ |S
* \ F V
* \-----S4
*
* For greedy loops we reverse our expectation and expect to match rather
* than fail. Therefore we want the loop code to look like this (U is the
* unwind code that steps back in the greedy loop). The following alternatives
* look the same as above.
* _____
* / \
* V |
* ----------> S1 |
* /| |
* / |S |
* F/ \_____/
* /
* |<-----------
* | \
* V \
* Q2 ---> S2 \
* | S / |
* F| / |
* | F/ |
* | / |
* | R |
* | / |
* F VL |
* <------U |
* back |S |
* \______________/
*/
void ChoiceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
int choice_count = alternatives_->length();
#ifdef DEBUG
for (int i = 0; i < choice_count - 1; i++) {
GuardedAlternative alternative = alternatives_->at(i);
ZoneList<Guard*>* guards = alternative.guards();
int guard_count = (guards == NULL) ? 0 : guards->length();
for (int j = 0; j < guard_count; j++) {
ASSERT(!trace->mentions_reg(guards->at(j)->reg()));
}
}
#endif
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
int new_flush_budget = trace->flush_budget() / choice_count;
if (trace->flush_budget() == 0 && trace->actions() != NULL) {
trace->Flush(compiler, this);
return;
}
RecursionCheck rc(compiler);
Trace* current_trace = trace;
int text_length = GreedyLoopTextLengthForAlternative(&(alternatives_->at(0)));
bool greedy_loop = false;
Label greedy_loop_label;
Trace counter_backtrack_trace;
counter_backtrack_trace.set_backtrack(&greedy_loop_label);
if (not_at_start()) counter_backtrack_trace.set_at_start(false);
if (choice_count > 1 && text_length != kNodeIsTooComplexForGreedyLoops) {
// Here we have special handling for greedy loops containing only text nodes
// and other simple nodes. These are handled by pushing the current
// position on the stack and then incrementing the current position each
// time around the switch. On backtrack we decrement the current position
// and check it against the pushed value. This avoids pushing backtrack
// information for each iteration of the loop, which could take up a lot of
// space.
greedy_loop = true;
ASSERT(trace->stop_node() == NULL);
macro_assembler->PushCurrentPosition();
current_trace = &counter_backtrack_trace;
Label greedy_match_failed;
Trace greedy_match_trace;
if (not_at_start()) greedy_match_trace.set_at_start(false);
greedy_match_trace.set_backtrack(&greedy_match_failed);
Label loop_label;
macro_assembler->Bind(&loop_label);
greedy_match_trace.set_stop_node(this);
greedy_match_trace.set_loop_label(&loop_label);
alternatives_->at(0).node()->Emit(compiler, &greedy_match_trace);
macro_assembler->Bind(&greedy_match_failed);
}
Label second_choice; // For use in greedy matches.
macro_assembler->Bind(&second_choice);
int first_normal_choice = greedy_loop ? 1 : 0;
int preload_characters =
CalculatePreloadCharacters(compiler,
current_trace->at_start() == Trace::FALSE);
bool preload_is_current =
(current_trace->characters_preloaded() == preload_characters);
bool preload_has_checked_bounds = preload_is_current;
AlternativeGenerationList alt_gens(choice_count);
// For now we just call all choices one after the other. The idea ultimately
// is to use the Dispatch table to try only the relevant ones.
for (int i = first_normal_choice; i < choice_count; i++) {
GuardedAlternative alternative = alternatives_->at(i);
AlternativeGeneration* alt_gen = alt_gens.at(i);
alt_gen->quick_check_details.set_characters(preload_characters);
ZoneList<Guard*>* guards = alternative.guards();
int guard_count = (guards == NULL) ? 0 : guards->length();
Trace new_trace(*current_trace);
new_trace.set_characters_preloaded(preload_is_current ?
preload_characters :
0);
if (preload_has_checked_bounds) {
new_trace.set_bound_checked_up_to(preload_characters);
}
new_trace.quick_check_performed()->Clear();
if (not_at_start_) new_trace.set_at_start(Trace::FALSE);
alt_gen->expects_preload = preload_is_current;
bool generate_full_check_inline = false;
if (FLAG_regexp_optimization &&
try_to_emit_quick_check_for_alternative(i) &&
alternative.node()->EmitQuickCheck(compiler,
&new_trace,
preload_has_checked_bounds,
&alt_gen->possible_success,
&alt_gen->quick_check_details,
i < choice_count - 1)) {
// Quick check was generated for this choice.
preload_is_current = true;
preload_has_checked_bounds = true;
// On the last choice in the ChoiceNode we generated the quick
// check to fall through on possible success. So now we need to
// generate the full check inline.
if (i == choice_count - 1) {
macro_assembler->Bind(&alt_gen->possible_success);
new_trace.set_quick_check_performed(&alt_gen->quick_check_details);
new_trace.set_characters_preloaded(preload_characters);
new_trace.set_bound_checked_up_to(preload_characters);
generate_full_check_inline = true;
}
} else if (alt_gen->quick_check_details.cannot_match()) {
if (i == choice_count - 1 && !greedy_loop) {
macro_assembler->GoTo(trace->backtrack());
}
continue;
} else {
// No quick check was generated. Put the full code here.
// If this is not the first choice then there could be slow checks from
// previous cases that go here when they fail. There's no reason to
// insist that they preload characters since the slow check we are about
// to generate probably can't use it.
if (i != first_normal_choice) {
alt_gen->expects_preload = false;
new_trace.InvalidateCurrentCharacter();
}
if (i < choice_count - 1) {
new_trace.set_backtrack(&alt_gen->after);
}
generate_full_check_inline = true;
}
if (generate_full_check_inline) {
if (new_trace.actions() != NULL) {
new_trace.set_flush_budget(new_flush_budget);
}
for (int j = 0; j < guard_count; j++) {
GenerateGuard(macro_assembler, guards->at(j), &new_trace);
}
alternative.node()->Emit(compiler, &new_trace);
preload_is_current = false;
}
macro_assembler->Bind(&alt_gen->after);
}
if (greedy_loop) {
macro_assembler->Bind(&greedy_loop_label);
// If we have unwound to the bottom then backtrack.
macro_assembler->CheckGreedyLoop(trace->backtrack());
// Otherwise try the second priority at an earlier position.
macro_assembler->AdvanceCurrentPosition(-text_length);
macro_assembler->GoTo(&second_choice);
}
// At this point we need to generate slow checks for the alternatives where
// the quick check was inlined. We can recognize these because the associated
// label was bound.
for (int i = first_normal_choice; i < choice_count - 1; i++) {
AlternativeGeneration* alt_gen = alt_gens.at(i);
Trace new_trace(*current_trace);
// If there are actions to be flushed we have to limit how many times
// they are flushed. Take the budget of the parent trace and distribute
// it fairly amongst the children.
if (new_trace.actions() != NULL) {
new_trace.set_flush_budget(new_flush_budget);
}
EmitOutOfLineContinuation(compiler,
&new_trace,
alternatives_->at(i),
alt_gen,
preload_characters,
alt_gens.at(i + 1)->expects_preload);
}
}
void ChoiceNode::EmitOutOfLineContinuation(RegExpCompiler* compiler,
Trace* trace,
GuardedAlternative alternative,
AlternativeGeneration* alt_gen,
int preload_characters,
bool next_expects_preload) {
if (!alt_gen->possible_success.is_linked()) return;
RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
macro_assembler->Bind(&alt_gen->possible_success);
Trace out_of_line_trace(*trace);
out_of_line_trace.set_characters_preloaded(preload_characters);
out_of_line_trace.set_quick_check_performed(&alt_gen->quick_check_details);
if (not_at_start_) out_of_line_trace.set_at_start(Trace::FALSE);
ZoneList<Guard*>* guards = alternative.guards();
int guard_count = (guards == NULL) ? 0 : guards->length();
if (next_expects_preload) {
Label reload_current_char;
out_of_line_trace.set_backtrack(&reload_current_char);
for (int j = 0; j < guard_count; j++) {
GenerateGuard(macro_assembler, guards->at(j), &out_of_line_trace);
}
alternative.node()->Emit(compiler, &out_of_line_trace);
macro_assembler->Bind(&reload_current_char);
// Reload the current character, since the next quick check expects that.
// We don't need to check bounds here because we only get into this
// code through a quick check which already did the checked load.
macro_assembler->LoadCurrentCharacter(trace->cp_offset(),
NULL,
false,
preload_characters);
macro_assembler->GoTo(&(alt_gen->after));
} else {
out_of_line_trace.set_backtrack(&(alt_gen->after));
for (int j = 0; j < guard_count; j++) {
GenerateGuard(macro_assembler, guards->at(j), &out_of_line_trace);
}
alternative.node()->Emit(compiler, &out_of_line_trace);
}
}
void ActionNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
RecursionCheck rc(compiler);
switch (type_) {
case STORE_POSITION: {
Trace::DeferredCapture
new_capture(data_.u_position_register.reg,
data_.u_position_register.is_capture,
trace);
Trace new_trace = *trace;
new_trace.add_action(&new_capture);
on_success()->Emit(compiler, &new_trace);
break;
}
case INCREMENT_REGISTER: {
Trace::DeferredIncrementRegister
new_increment(data_.u_increment_register.reg);
Trace new_trace = *trace;
new_trace.add_action(&new_increment);
on_success()->Emit(compiler, &new_trace);
break;
}
case SET_REGISTER: {
Trace::DeferredSetRegister
new_set(data_.u_store_register.reg, data_.u_store_register.value);
Trace new_trace = *trace;
new_trace.add_action(&new_set);
on_success()->Emit(compiler, &new_trace);
break;
}
case CLEAR_CAPTURES: {
Trace::DeferredClearCaptures
new_capture(Interval(data_.u_clear_captures.range_from,
data_.u_clear_captures.range_to));
Trace new_trace = *trace;
new_trace.add_action(&new_capture);
on_success()->Emit(compiler, &new_trace);
break;
}
case BEGIN_SUBMATCH:
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
} else {
assembler->WriteCurrentPositionToRegister(
data_.u_submatch.current_position_register, 0);
assembler->WriteStackPointerToRegister(
data_.u_submatch.stack_pointer_register);
on_success()->Emit(compiler, trace);
}
break;
case EMPTY_MATCH_CHECK: {
int start_pos_reg = data_.u_empty_match_check.start_register;
int stored_pos = 0;
int rep_reg = data_.u_empty_match_check.repetition_register;
bool has_minimum = (rep_reg != RegExpCompiler::kNoRegister);
bool know_dist = trace->GetStoredPosition(start_pos_reg, &stored_pos);
if (know_dist && !has_minimum && stored_pos == trace->cp_offset()) {
// If we know we haven't advanced and there is no minimum we
// can just backtrack immediately.
assembler->GoTo(trace->backtrack());
} else if (know_dist && stored_pos < trace->cp_offset()) {
// If we know we've advanced we can generate the continuation
// immediately.
on_success()->Emit(compiler, trace);
} else if (!trace->is_trivial()) {
trace->Flush(compiler, this);
} else {
Label skip_empty_check;
// If we have a minimum number of repetitions we check the current
// number first and skip the empty check if it's not enough.
if (has_minimum) {
int limit = data_.u_empty_match_check.repetition_limit;
assembler->IfRegisterLT(rep_reg, limit, &skip_empty_check);
}
// If the match is empty we bail out, otherwise we fall through
// to the on-success continuation.
assembler->IfRegisterEqPos(data_.u_empty_match_check.start_register,
trace->backtrack());
assembler->Bind(&skip_empty_check);
on_success()->Emit(compiler, trace);
}
break;
}
case POSITIVE_SUBMATCH_SUCCESS: {
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
assembler->ReadCurrentPositionFromRegister(
data_.u_submatch.current_position_register);
assembler->ReadStackPointerFromRegister(
data_.u_submatch.stack_pointer_register);
int clear_register_count = data_.u_submatch.clear_register_count;
if (clear_register_count == 0) {
on_success()->Emit(compiler, trace);
return;
}
int clear_registers_from = data_.u_submatch.clear_register_from;
Label clear_registers_backtrack;
Trace new_trace = *trace;
new_trace.set_backtrack(&clear_registers_backtrack);
on_success()->Emit(compiler, &new_trace);
assembler->Bind(&clear_registers_backtrack);
int clear_registers_to = clear_registers_from + clear_register_count - 1;
assembler->ClearRegisters(clear_registers_from, clear_registers_to);
ASSERT(trace->backtrack() == NULL);
assembler->Backtrack();
return;
}
default:
UNREACHABLE();
}
}
void BackReferenceNode::Emit(RegExpCompiler* compiler, Trace* trace) {
RegExpMacroAssembler* assembler = compiler->macro_assembler();
if (!trace->is_trivial()) {
trace->Flush(compiler, this);
return;
}
LimitResult limit_result = LimitVersions(compiler, trace);
if (limit_result == DONE) return;
ASSERT(limit_result == CONTINUE);
RecursionCheck rc(compiler);
ASSERT_EQ(start_reg_ + 1, end_reg_);
if (compiler->ignore_case()) {
assembler->CheckNotBackReferenceIgnoreCase(start_reg_,
trace->backtrack());
} else {
assembler->CheckNotBackReference(start_reg_, trace->backtrack());
}
on_success()->Emit(compiler, trace);
}
// -------------------------------------------------------------------
// Dot/dotty output
#ifdef DEBUG
class DotPrinter: public NodeVisitor {
public:
explicit DotPrinter(bool ignore_case)
: ignore_case_(ignore_case),
stream_(&alloc_) { }
void PrintNode(const char* label, RegExpNode* node);
void Visit(RegExpNode* node);
void PrintAttributes(RegExpNode* from);
StringStream* stream() { return &stream_; }
void PrintOnFailure(RegExpNode* from, RegExpNode* to);
#define DECLARE_VISIT(Type) \
virtual void Visit##Type(Type##Node* that);
FOR_EACH_NODE_TYPE(DECLARE_VISIT)
#undef DECLARE_VISIT
private:
bool ignore_case_;
HeapStringAllocator alloc_;
StringStream stream_;
};
void DotPrinter::PrintNode(const char* label, RegExpNode* node) {
stream()->Add("digraph G {\n graph [label=\"");
for (int i = 0; label[i]; i++) {
switch (label[i]) {
case '\\':
stream()->Add("\\\\");
break;
case '"':
stream()->Add("\"");
break;
default:
stream()->Put(label[i]);
break;
}
}
stream()->Add("\"];\n");
Visit(node);
stream()->Add("}\n");
printf("%s", *(stream()->ToCString()));
}
void DotPrinter::Visit(RegExpNode* node) {
if (node->info()->visited) return;
node->info()->visited = true;
node->Accept(this);
}
void DotPrinter::PrintOnFailure(RegExpNode* from, RegExpNode* on_failure) {
stream()->Add(" n%p -> n%p [style=dotted];\n", from, on_failure);
Visit(on_failure);
}
class TableEntryBodyPrinter {
public:
TableEntryBodyPrinter(StringStream* stream, ChoiceNode* choice)
: stream_(stream), choice_(choice) { }
void Call(uc16 from, DispatchTable::Entry entry) {
OutSet* out_set = entry.out_set();
for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
if (out_set->Get(i)) {
stream()->Add(" n%p:s%io%i -> n%p;\n",
choice(),
from,
i,
choice()->alternatives()->at(i).node());
}
}
}
private:
StringStream* stream() { return stream_; }
ChoiceNode* choice() { return choice_; }
StringStream* stream_;
ChoiceNode* choice_;
};
class TableEntryHeaderPrinter {
public:
explicit TableEntryHeaderPrinter(StringStream* stream)
: first_(true), stream_(stream) { }
void Call(uc16 from, DispatchTable::Entry entry) {
if (first_) {
first_ = false;
} else {
stream()->Add("|");
}
stream()->Add("{\\%k-\\%k|{", from, entry.to());
OutSet* out_set = entry.out_set();
int priority = 0;
for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
if (out_set->Get(i)) {
if (priority > 0) stream()->Add("|");
stream()->Add("<s%io%i> %i", from, i, priority);
priority++;
}
}
stream()->Add("}}");
}
private:
bool first_;
StringStream* stream() { return stream_; }
StringStream* stream_;
};
class AttributePrinter {
public:
explicit AttributePrinter(DotPrinter* out)
: out_(out), first_(true) { }
void PrintSeparator() {
if (first_) {
first_ = false;
} else {
out_->stream()->Add("|");
}
}
void PrintBit(const char* name, bool value) {
if (!value) return;
PrintSeparator();
out_->stream()->Add("{%s}", name);
}
void PrintPositive(const char* name, int value) {
if (value < 0) return;
PrintSeparator();
out_->stream()->Add("{%s|%x}", name, value);
}
private:
DotPrinter* out_;
bool first_;
};
void DotPrinter::PrintAttributes(RegExpNode* that) {
stream()->Add(" a%p [shape=Mrecord, color=grey, fontcolor=grey, "
"margin=0.1, fontsize=10, label=\"{",
that);
AttributePrinter printer(this);
NodeInfo* info = that->info();
printer.PrintBit("NI", info->follows_newline_interest);
printer.PrintBit("WI", info->follows_word_interest);
printer.PrintBit("SI", info->follows_start_interest);
Label* label = that->label();
if (label->is_bound())
printer.PrintPositive("@", label->pos());
stream()->Add("}\"];\n");
stream()->Add(" a%p -> n%p [style=dashed, color=grey, "
"arrowhead=none];\n", that, that);
}
static const bool kPrintDispatchTable = false;
void DotPrinter::VisitChoice(ChoiceNode* that) {
if (kPrintDispatchTable) {
stream()->Add(" n%p [shape=Mrecord, label=\"", that);
TableEntryHeaderPrinter header_printer(stream());
that->GetTable(ignore_case_)->ForEach(&header_printer);
stream()->Add("\"]\n", that);
PrintAttributes(that);
TableEntryBodyPrinter body_printer(stream(), that);
that->GetTable(ignore_case_)->ForEach(&body_printer);
} else {
stream()->Add(" n%p [shape=Mrecord, label=\"?\"];\n", that);
for (int i = 0; i < that->alternatives()->length(); i++) {
GuardedAlternative alt = that->alternatives()->at(i);
stream()->Add(" n%p -> n%p;\n", that, alt.node());
}
}
for (int i = 0; i < that->alternatives()->length(); i++) {
GuardedAlternative alt = that->alternatives()->at(i);
alt.node()->Accept(this);
}
}
void DotPrinter::VisitText(TextNode* that) {
stream()->Add(" n%p [label=\"", that);
for (int i = 0; i < that->elements()->length(); i++) {
if (i > 0) stream()->Add(" ");
TextElement elm = that->elements()->at(i);
switch (elm.type) {
case TextElement::ATOM: {
stream()->Add("'%w'", elm.data.u_atom->data());
break;
}
case TextElement::CHAR_CLASS: {
RegExpCharacterClass* node = elm.data.u_char_class;
stream()->Add("[");
if (node->is_negated())
stream()->Add("^");
for (int j = 0; j < node->ranges()->length(); j++) {
CharacterRange range = node->ranges()->at(j);
stream()->Add("%k-%k", range.from(), range.to());
}
stream()->Add("]");
break;
}
default:
UNREACHABLE();
}
}
stream()->Add("\", shape=box, peripheries=2];\n");
PrintAttributes(that);
stream()->Add(" n%p -> n%p;\n", that, that->on_success());
Visit(that->on_success());
}
void DotPrinter::VisitBackReference(BackReferenceNode* that) {
stream()->Add(" n%p [label=\"$%i..$%i\", shape=doubleoctagon];\n",
that,
that->start_register(),
that->end_register());
PrintAttributes(that);
stream()->Add(" n%p -> n%p;\n", that, that->on_success());
Visit(that->on_success());
}
void DotPrinter::VisitEnd(EndNode* that) {
stream()->Add(" n%p [style=bold, shape=point];\n", that);
PrintAttributes(that);
}
void DotPrinter::VisitAssertion(AssertionNode* that) {
stream()->Add(" n%p [", that);
switch (that->type()) {
case AssertionNode::AT_END:
stream()->Add("label=\"$\", shape=septagon");
break;
case AssertionNode::AT_START:
stream()->Add("label=\"^\", shape=septagon");
break;
case AssertionNode::AT_BOUNDARY:
stream()->Add("label=\"\\b\", shape=septagon");
break;
case AssertionNode::AT_NON_BOUNDARY:
stream()->Add("label=\"\\B\", shape=septagon");
break;
case AssertionNode::AFTER_NEWLINE:
stream()->Add("label=\"(?<=\\n)\", shape=septagon");
break;
case AssertionNode::AFTER_WORD_CHARACTER:
stream()->Add("label=\"(?<=\\w)\", shape=septagon");
break;
case AssertionNode::AFTER_NONWORD_CHARACTER:
stream()->Add("label=\"(?<=\\W)\", shape=septagon");
break;
}
stream()->Add("];\n");
PrintAttributes(that);
RegExpNode* successor = that->on_success();
stream()->Add(" n%p -> n%p;\n", that, successor);
Visit(successor);
}
void DotPrinter::VisitAction(ActionNode* that) {
stream()->Add(" n%p [", that);
switch (that->type_) {
case ActionNode::SET_REGISTER:
stream()->Add("label=\"$%i:=%i\", shape=octagon",
that->data_.u_store_register.reg,
that->data_.u_store_register.value);
break;
case ActionNode::INCREMENT_REGISTER:
stream()->Add("label=\"$%i++\", shape=octagon",
that->data_.u_increment_register.reg);
break;
case ActionNode::STORE_POSITION:
stream()->Add("label=\"$%i:=$pos\", shape=octagon",
that->data_.u_position_register.reg);
break;
case ActionNode::BEGIN_SUBMATCH:
stream()->Add("label=\"$%i:=$pos,begin\", shape=septagon",
that->data_.u_submatch.current_position_register);
break;
case ActionNode::POSITIVE_SUBMATCH_SUCCESS:
stream()->Add("label=\"escape\", shape=septagon");
break;
case ActionNode::EMPTY_MATCH_CHECK:
stream()->Add("label=\"$%i=$pos?,$%i<%i?\", shape=septagon",
that->data_.u_empty_match_check.start_register,
that->data_.u_empty_match_check.repetition_register,
that->data_.u_empty_match_check.repetition_limit);
break;
case ActionNode::CLEAR_CAPTURES: {
stream()->Add("label=\"clear $%i to $%i\", shape=septagon",
that->data_.u_clear_captures.range_from,
that->data_.u_clear_captures.range_to);
break;
}
}
stream()->Add("];\n");
PrintAttributes(that);
RegExpNode* successor = that->on_success();
stream()->Add(" n%p -> n%p;\n", that, successor);
Visit(successor);
}
class DispatchTableDumper {
public:
explicit DispatchTableDumper(StringStream* stream) : stream_(stream) { }
void Call(uc16 key, DispatchTable::Entry entry);
StringStream* stream() { return stream_; }
private:
StringStream* stream_;
};
void DispatchTableDumper::Call(uc16 key, DispatchTable::Entry entry) {
stream()->Add("[%k-%k]: {", key, entry.to());
OutSet* set = entry.out_set();
bool first = true;
for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
if (set->Get(i)) {
if (first) {
first = false;
} else {
stream()->Add(", ");
}
stream()->Add("%i", i);
}
}
stream()->Add("}\n");
}
void DispatchTable::Dump() {
HeapStringAllocator alloc;
StringStream stream(&alloc);
DispatchTableDumper dumper(&stream);
tree()->ForEach(&dumper);
OS::PrintError("%s", *stream.ToCString());
}
void RegExpEngine::DotPrint(const char* label,
RegExpNode* node,
bool ignore_case) {
DotPrinter printer(ignore_case);
printer.PrintNode(label, node);
}
#endif // DEBUG
// -------------------------------------------------------------------
// Tree to graph conversion
static const uc16 kSpaceRanges[] = { 0x0009, 0x000D, 0x0020, 0x0020, 0x00A0,
0x00A0, 0x1680, 0x1680, 0x180E, 0x180E, 0x2000, 0x200A, 0x2028, 0x2029,
0x202F, 0x202F, 0x205F, 0x205F, 0x3000, 0x3000, 0xFEFF, 0xFEFF };
static const int kSpaceRangeCount = ARRAY_SIZE(kSpaceRanges);
static const uc16 kWordRanges[] = { '0', '9', 'A', 'Z', '_', '_', 'a', 'z' };
static const int kWordRangeCount = ARRAY_SIZE(kWordRanges);
static const uc16 kDigitRanges[] = { '0', '9' };
static const int kDigitRangeCount = ARRAY_SIZE(kDigitRanges);
static const uc16 kLineTerminatorRanges[] = { 0x000A, 0x000A, 0x000D, 0x000D,
0x2028, 0x2029 };
static const int kLineTerminatorRangeCount = ARRAY_SIZE(kLineTerminatorRanges);
RegExpNode* RegExpAtom::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
ZoneList<TextElement>* elms = new ZoneList<TextElement>(1);
elms->Add(TextElement::Atom(this));
return new TextNode(elms, on_success);
}
RegExpNode* RegExpText::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return new TextNode(elements(), on_success);
}
static bool CompareInverseRanges(ZoneList<CharacterRange>* ranges,
const uc16* special_class,
int length) {
ASSERT(ranges->length() != 0);
ASSERT(length != 0);
ASSERT(special_class[0] != 0);
if (ranges->length() != (length >> 1) + 1) {
return false;
}
CharacterRange range = ranges->at(0);
if (range.from() != 0) {
return false;
}
for (int i = 0; i < length; i += 2) {
if (special_class[i] != (range.to() + 1)) {
return false;
}
range = ranges->at((i >> 1) + 1);
if (special_class[i+1] != range.from() - 1) {
return false;
}
}
if (range.to() != 0xffff) {
return false;
}
return true;
}
static bool CompareRanges(ZoneList<CharacterRange>* ranges,
const uc16* special_class,
int length) {
if (ranges->length() * 2 != length) {
return false;
}
for (int i = 0; i < length; i += 2) {
CharacterRange range = ranges->at(i >> 1);
if (range.from() != special_class[i] || range.to() != special_class[i+1]) {
return false;
}
}
return true;
}
bool RegExpCharacterClass::is_standard() {
// TODO(lrn): Remove need for this function, by not throwing away information
// along the way.
if (is_negated_) {
return false;
}
if (set_.is_standard()) {
return true;
}
if (CompareRanges(set_.ranges(), kSpaceRanges, kSpaceRangeCount)) {
set_.set_standard_set_type('s');
return true;
}
if (CompareInverseRanges(set_.ranges(), kSpaceRanges, kSpaceRangeCount)) {
set_.set_standard_set_type('S');
return true;
}
if (CompareInverseRanges(set_.ranges(),
kLineTerminatorRanges,
kLineTerminatorRangeCount)) {
set_.set_standard_set_type('.');
return true;
}
if (CompareRanges(set_.ranges(),
kLineTerminatorRanges,
kLineTerminatorRangeCount)) {
set_.set_standard_set_type('n');
return true;
}
if (CompareRanges(set_.ranges(), kWordRanges, kWordRangeCount)) {
set_.set_standard_set_type('w');
return true;
}
if (CompareInverseRanges(set_.ranges(), kWordRanges, kWordRangeCount)) {
set_.set_standard_set_type('W');
return true;
}
return false;
}
RegExpNode* RegExpCharacterClass::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return new TextNode(this, on_success);
}
RegExpNode* RegExpDisjunction::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
ZoneList<RegExpTree*>* alternatives = this->alternatives();
int length = alternatives->length();
ChoiceNode* result = new ChoiceNode(length);
for (int i = 0; i < length; i++) {
GuardedAlternative alternative(alternatives->at(i)->ToNode(compiler,
on_success));
result->AddAlternative(alternative);
}
return result;
}
RegExpNode* RegExpQuantifier::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return ToNode(min(),
max(),
is_greedy(),
body(),
compiler,
on_success);
}
// Scoped object to keep track of how much we unroll quantifier loops in the
// regexp graph generator.
class RegExpExpansionLimiter {
public:
static const int kMaxExpansionFactor = 6;
RegExpExpansionLimiter(RegExpCompiler* compiler, int factor)
: compiler_(compiler),
saved_expansion_factor_(compiler->current_expansion_factor()),
ok_to_expand_(saved_expansion_factor_ <= kMaxExpansionFactor) {
ASSERT(factor > 0);
if (ok_to_expand_) {
if (factor > kMaxExpansionFactor) {
// Avoid integer overflow of the current expansion factor.
ok_to_expand_ = false;
compiler->set_current_expansion_factor(kMaxExpansionFactor + 1);
} else {
int new_factor = saved_expansion_factor_ * factor;
ok_to_expand_ = (new_factor <= kMaxExpansionFactor);
compiler->set_current_expansion_factor(new_factor);
}
}
}
~RegExpExpansionLimiter() {
compiler_->set_current_expansion_factor(saved_expansion_factor_);
}
bool ok_to_expand() { return ok_to_expand_; }
private:
RegExpCompiler* compiler_;
int saved_expansion_factor_;
bool ok_to_expand_;
DISALLOW_IMPLICIT_CONSTRUCTORS(RegExpExpansionLimiter);
};
RegExpNode* RegExpQuantifier::ToNode(int min,
int max,
bool is_greedy,
RegExpTree* body,
RegExpCompiler* compiler,
RegExpNode* on_success,
bool not_at_start) {
// x{f, t} becomes this:
//
// (r++)<-.
// | `
// | (x)
// v ^
// (r=0)-->(?)---/ [if r < t]
// |
// [if r >= f] \----> ...
//
// 15.10.2.5 RepeatMatcher algorithm.
// The parser has already eliminated the case where max is 0. In the case
// where max_match is zero the parser has removed the quantifier if min was
// > 0 and removed the atom if min was 0. See AddQuantifierToAtom.
// If we know that we cannot match zero length then things are a little
// simpler since we don't need to make the special zero length match check
// from step 2.1. If the min and max are small we can unroll a little in
// this case.
static const int kMaxUnrolledMinMatches = 3; // Unroll (foo)+ and (foo){3,}
static const int kMaxUnrolledMaxMatches = 3; // Unroll (foo)? and (foo){x,3}
if (max == 0) return on_success; // This can happen due to recursion.
bool body_can_be_empty = (body->min_match() == 0);
int body_start_reg = RegExpCompiler::kNoRegister;
Interval capture_registers = body->CaptureRegisters();
bool needs_capture_clearing = !capture_registers.is_empty();
if (body_can_be_empty) {
body_start_reg = compiler->AllocateRegister();
} else if (FLAG_regexp_optimization && !needs_capture_clearing) {
// Only unroll if there are no captures and the body can't be
// empty.
{
RegExpExpansionLimiter limiter(
compiler, min + ((max != min) ? 1 : 0));
if (min > 0 && min <= kMaxUnrolledMinMatches && limiter.ok_to_expand()) {
int new_max = (max == kInfinity) ? max : max - min;
// Recurse once to get the loop or optional matches after the fixed
// ones.
RegExpNode* answer = ToNode(
0, new_max, is_greedy, body, compiler, on_success, true);
// Unroll the forced matches from 0 to min. This can cause chains of
// TextNodes (which the parser does not generate). These should be
// combined if it turns out they hinder good code generation.
for (int i = 0; i < min; i++) {
answer = body->ToNode(compiler, answer);
}
return answer;
}
}
if (max <= kMaxUnrolledMaxMatches && min == 0) {
ASSERT(max > 0); // Due to the 'if' above.
RegExpExpansionLimiter limiter(compiler, max);
if (limiter.ok_to_expand()) {
// Unroll the optional matches up to max.
RegExpNode* answer = on_success;
for (int i = 0; i < max; i++) {
ChoiceNode* alternation = new ChoiceNode(2);
if (is_greedy) {
alternation->AddAlternative(
GuardedAlternative(body->ToNode(compiler, answer)));
alternation->AddAlternative(GuardedAlternative(on_success));
} else {
alternation->AddAlternative(GuardedAlternative(on_success));
alternation->AddAlternative(
GuardedAlternative(body->ToNode(compiler, answer)));
}
answer = alternation;
if (not_at_start) alternation->set_not_at_start();
}
return answer;
}
}
}
bool has_min = min > 0;
bool has_max = max < RegExpTree::kInfinity;
bool needs_counter = has_min || has_max;
int reg_ctr = needs_counter
? compiler->AllocateRegister()
: RegExpCompiler::kNoRegister;
LoopChoiceNode* center = new LoopChoiceNode(body->min_match() == 0);
if (not_at_start) center->set_not_at_start();
RegExpNode* loop_return = needs_counter
? static_cast<RegExpNode*>(ActionNode::IncrementRegister(reg_ctr, center))
: static_cast<RegExpNode*>(center);
if (body_can_be_empty) {
// If the body can be empty we need to check if it was and then
// backtrack.
loop_return = ActionNode::EmptyMatchCheck(body_start_reg,
reg_ctr,
min,
loop_return);
}
RegExpNode* body_node = body->ToNode(compiler, loop_return);
if (body_can_be_empty) {
// If the body can be empty we need to store the start position
// so we can bail out if it was empty.
body_node = ActionNode::StorePosition(body_start_reg, false, body_node);
}
if (needs_capture_clearing) {
// Before entering the body of this loop we need to clear captures.
body_node = ActionNode::ClearCaptures(capture_registers, body_node);
}
GuardedAlternative body_alt(body_node);
if (has_max) {
Guard* body_guard = new Guard(reg_ctr, Guard::LT, max);
body_alt.AddGuard(body_guard);
}
GuardedAlternative rest_alt(on_success);
if (has_min) {
Guard* rest_guard = new Guard(reg_ctr, Guard::GEQ, min);
rest_alt.AddGuard(rest_guard);
}
if (is_greedy) {
center->AddLoopAlternative(body_alt);
center->AddContinueAlternative(rest_alt);
} else {
center->AddContinueAlternative(rest_alt);
center->AddLoopAlternative(body_alt);
}
if (needs_counter) {
return ActionNode::SetRegister(reg_ctr, 0, center);
} else {
return center;
}
}
RegExpNode* RegExpAssertion::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
NodeInfo info;
switch (type()) {
case START_OF_LINE:
return AssertionNode::AfterNewline(on_success);
case START_OF_INPUT:
return AssertionNode::AtStart(on_success);
case BOUNDARY:
return AssertionNode::AtBoundary(on_success);
case NON_BOUNDARY:
return AssertionNode::AtNonBoundary(on_success);
case END_OF_INPUT:
return AssertionNode::AtEnd(on_success);
case END_OF_LINE: {
// Compile $ in multiline regexps as an alternation with a positive
// lookahead in one side and an end-of-input on the other side.
// We need two registers for the lookahead.
int stack_pointer_register = compiler->AllocateRegister();
int position_register = compiler->AllocateRegister();
// The ChoiceNode to distinguish between a newline and end-of-input.
ChoiceNode* result = new ChoiceNode(2);
// Create a newline atom.
ZoneList<CharacterRange>* newline_ranges =
new ZoneList<CharacterRange>(3);
CharacterRange::AddClassEscape('n', newline_ranges);
RegExpCharacterClass* newline_atom = new RegExpCharacterClass('n');
TextNode* newline_matcher = new TextNode(
newline_atom,
ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
position_register,
0, // No captures inside.
-1, // Ignored if no captures.
on_success));
// Create an end-of-input matcher.
RegExpNode* end_of_line = ActionNode::BeginSubmatch(
stack_pointer_register,
position_register,
newline_matcher);
// Add the two alternatives to the ChoiceNode.
GuardedAlternative eol_alternative(end_of_line);
result->AddAlternative(eol_alternative);
GuardedAlternative end_alternative(AssertionNode::AtEnd(on_success));
result->AddAlternative(end_alternative);
return result;
}
default:
UNREACHABLE();
}
return on_success;
}
RegExpNode* RegExpBackReference::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return new BackReferenceNode(RegExpCapture::StartRegister(index()),
RegExpCapture::EndRegister(index()),
on_success);
}
RegExpNode* RegExpEmpty::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return on_success;
}
RegExpNode* RegExpLookahead::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
int stack_pointer_register = compiler->AllocateRegister();
int position_register = compiler->AllocateRegister();
const int registers_per_capture = 2;
const int register_of_first_capture = 2;
int register_count = capture_count_ * registers_per_capture;
int register_start =
register_of_first_capture + capture_from_ * registers_per_capture;
RegExpNode* success;
if (is_positive()) {
RegExpNode* node = ActionNode::BeginSubmatch(
stack_pointer_register,
position_register,
body()->ToNode(
compiler,
ActionNode::PositiveSubmatchSuccess(stack_pointer_register,
position_register,
register_count,
register_start,
on_success)));
return node;
} else {
// We use a ChoiceNode for a negative lookahead because it has most of
// the characteristics we need. It has the body of the lookahead as its
// first alternative and the expression after the lookahead of the second
// alternative. If the first alternative succeeds then the
// NegativeSubmatchSuccess will unwind the stack including everything the
// choice node set up and backtrack. If the first alternative fails then
// the second alternative is tried, which is exactly the desired result
// for a negative lookahead. The NegativeLookaheadChoiceNode is a special
// ChoiceNode that knows to ignore the first exit when calculating quick
// checks.
GuardedAlternative body_alt(
body()->ToNode(
compiler,
success = new NegativeSubmatchSuccess(stack_pointer_register,
position_register,
register_count,
register_start)));
ChoiceNode* choice_node =
new NegativeLookaheadChoiceNode(body_alt,
GuardedAlternative(on_success));
return ActionNode::BeginSubmatch(stack_pointer_register,
position_register,
choice_node);
}
}
RegExpNode* RegExpCapture::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
return ToNode(body(), index(), compiler, on_success);
}
RegExpNode* RegExpCapture::ToNode(RegExpTree* body,
int index,
RegExpCompiler* compiler,
RegExpNode* on_success) {
int start_reg = RegExpCapture::StartRegister(index);
int end_reg = RegExpCapture::EndRegister(index);
RegExpNode* store_end = ActionNode::StorePosition(end_reg, true, on_success);
RegExpNode* body_node = body->ToNode(compiler, store_end);
return ActionNode::StorePosition(start_reg, true, body_node);
}
RegExpNode* RegExpAlternative::ToNode(RegExpCompiler* compiler,
RegExpNode* on_success) {
ZoneList<RegExpTree*>* children = nodes();
RegExpNode* current = on_success;
for (int i = children->length() - 1; i >= 0; i--) {
current = children->at(i)->ToNode(compiler, current);
}
return current;
}
static void AddClass(const uc16* elmv,
int elmc,
ZoneList<CharacterRange>* ranges) {
for (int i = 0; i < elmc; i += 2) {
ASSERT(elmv[i] <= elmv[i + 1]);
ranges->Add(CharacterRange(elmv[i], elmv[i + 1]));
}
}
static void AddClassNegated(const uc16 *elmv,
int elmc,
ZoneList<CharacterRange>* ranges) {
ASSERT(elmv[0] != 0x0000);
ASSERT(elmv[elmc-1] != String::kMaxUC16CharCode);
uc16 last = 0x0000;
for (int i = 0; i < elmc; i += 2) {
ASSERT(last <= elmv[i] - 1);
ASSERT(elmv[i] <= elmv[i + 1]);
ranges->Add(CharacterRange(last, elmv[i] - 1));
last = elmv[i + 1] + 1;
}
ranges->Add(CharacterRange(last, String::kMaxUC16CharCode));
}
void CharacterRange::AddClassEscape(uc16 type,
ZoneList<CharacterRange>* ranges) {
switch (type) {
case 's':
AddClass(kSpaceRanges, kSpaceRangeCount, ranges);
break;
case 'S':
AddClassNegated(kSpaceRanges, kSpaceRangeCount, ranges);
break;
case 'w':
AddClass(kWordRanges, kWordRangeCount, ranges);
break;
case 'W':
AddClassNegated(kWordRanges, kWordRangeCount, ranges);
break;
case 'd':
AddClass(kDigitRanges, kDigitRangeCount, ranges);
break;
case 'D':
AddClassNegated(kDigitRanges, kDigitRangeCount, ranges);
break;
case '.':
AddClassNegated(kLineTerminatorRanges,
kLineTerminatorRangeCount,
ranges);
break;
// This is not a character range as defined by the spec but a
// convenient shorthand for a character class that matches any
// character.
case '*':
ranges->Add(CharacterRange::Everything());
break;
// This is the set of characters matched by the $ and ^ symbols
// in multiline mode.
case 'n':
AddClass(kLineTerminatorRanges,
kLineTerminatorRangeCount,
ranges);
break;
default:
UNREACHABLE();
}
}
Vector<const uc16> CharacterRange::GetWordBounds() {
return Vector<const uc16>(kWordRanges, kWordRangeCount);
}
class CharacterRangeSplitter {
public:
CharacterRangeSplitter(ZoneList<CharacterRange>** included,
ZoneList<CharacterRange>** excluded)
: included_(included),
excluded_(excluded) { }
void Call(uc16 from, DispatchTable::Entry entry);
static const int kInBase = 0;
static const int kInOverlay = 1;
private:
ZoneList<CharacterRange>** included_;
ZoneList<CharacterRange>** excluded_;
};
void CharacterRangeSplitter::Call(uc16 from, DispatchTable::Entry entry) {
if (!entry.out_set()->Get(kInBase)) return;
ZoneList<CharacterRange>** target = entry.out_set()->Get(kInOverlay)
? included_
: excluded_;
if (*target == NULL) *target = new ZoneList<CharacterRange>(2);
(*target)->Add(CharacterRange(entry.from(), entry.to()));
}
void CharacterRange::Split(ZoneList<CharacterRange>* base,
Vector<const uc16> overlay,
ZoneList<CharacterRange>** included,
ZoneList<CharacterRange>** excluded) {
ASSERT_EQ(NULL, *included);
ASSERT_EQ(NULL, *excluded);
DispatchTable table;
for (int i = 0; i < base->length(); i++)
table.AddRange(base->at(i), CharacterRangeSplitter::kInBase);
for (int i = 0; i < overlay.length(); i += 2) {
table.AddRange(CharacterRange(overlay[i], overlay[i+1]),
CharacterRangeSplitter::kInOverlay);
}
CharacterRangeSplitter callback(included, excluded);
table.ForEach(&callback);
}
void CharacterRange::AddCaseEquivalents(ZoneList<CharacterRange>* ranges,
bool is_ascii) {
Isolate* isolate = Isolate::Current();
uc16 bottom = from();
uc16 top = to();
if (is_ascii) {
if (bottom > String::kMaxAsciiCharCode) return;
if (top > String::kMaxAsciiCharCode) top = String::kMaxAsciiCharCode;
}
unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
if (top == bottom) {
// If this is a singleton we just expand the one character.
int length = isolate->jsregexp_uncanonicalize()->get(bottom, '\0', chars);
for (int i = 0; i < length; i++) {
uc32 chr = chars[i];
if (chr != bottom) {
ranges->Add(CharacterRange::Singleton(chars[i]));
}
}
} else {
// If this is a range we expand the characters block by block,
// expanding contiguous subranges (blocks) one at a time.
// The approach is as follows. For a given start character we
// look up the remainder of the block that contains it (represented
// by the end point), for instance we find 'z' if the character
// is 'c'. A block is characterized by the property
// that all characters uncanonicalize in the same way, except that
// each entry in the result is incremented by the distance from the first
// element. So a-z is a block because 'a' uncanonicalizes to ['a', 'A'] and
// the k'th letter uncanonicalizes to ['a' + k, 'A' + k].
// Once we've found the end point we look up its uncanonicalization
// and produce a range for each element. For instance for [c-f]
// we look up ['z', 'Z'] and produce [c-f] and [C-F]. We then only
// add a range if it is not already contained in the input, so [c-f]
// will be skipped but [C-F] will be added. If this range is not
// completely contained in a block we do this for all the blocks
// covered by the range (handling characters that is not in a block
// as a "singleton block").
unibrow::uchar range[unibrow::Ecma262UnCanonicalize::kMaxWidth];
int pos = bottom;
while (pos < top) {
int length = isolate->jsregexp_canonrange()->get(pos, '\0', range);
uc16 block_end;
if (length == 0) {
block_end = pos;
} else {
ASSERT_EQ(1, length);
block_end = range[0];
}
int end = (block_end > top) ? top : block_end;
length = isolate->jsregexp_uncanonicalize()->get(block_end, '\0', range);
for (int i = 0; i < length; i++) {
uc32 c = range[i];
uc16 range_from = c - (block_end - pos);
uc16 range_to = c - (block_end - end);
if (!(bottom <= range_from && range_to <= top)) {
ranges->Add(CharacterRange(range_from, range_to));
}
}
pos = end + 1;
}
}
}
bool CharacterRange::IsCanonical(ZoneList<CharacterRange>* ranges) {
ASSERT_NOT_NULL(ranges);
int n = ranges->length();
if (n <= 1) return true;
int max = ranges->at(0).to();
for (int i = 1; i < n; i++) {
CharacterRange next_range = ranges->at(i);
if (next_range.from() <= max + 1) return false;
max = next_range.to();
}
return true;
}
SetRelation CharacterRange::WordCharacterRelation(
ZoneList<CharacterRange>* range) {
ASSERT(IsCanonical(range));
int i = 0; // Word character range index.
int j = 0; // Argument range index.
ASSERT_NE(0, kWordRangeCount);
SetRelation result;
if (range->length() == 0) {
result.SetElementsInSecondSet();
return result;
}
CharacterRange argument_range = range->at(0);
CharacterRange word_range = CharacterRange(kWordRanges[0], kWordRanges[1]);
while (i < kWordRangeCount && j < range->length()) {
// Check the two ranges for the five cases:
// - no overlap.
// - partial overlap (there are elements in both ranges that isn't
// in the other, and there are also elements that are in both).
// - argument range entirely inside word range.
// - word range entirely inside argument range.
// - ranges are completely equal.
// First check for no overlap. The earlier range is not in the other set.
if (argument_range.from() > word_range.to()) {
// Ranges are disjoint. The earlier word range contains elements that
// cannot be in the argument set.
result.SetElementsInSecondSet();
} else if (word_range.from() > argument_range.to()) {
// Ranges are disjoint. The earlier argument range contains elements that
// cannot be in the word set.
result.SetElementsInFirstSet();
} else if (word_range.from() <= argument_range.from() &&
word_range.to() >= argument_range.from()) {
result.SetElementsInBothSets();
// argument range completely inside word range.
if (word_range.from() < argument_range.from() ||
word_range.to() > argument_range.from()) {
result.SetElementsInSecondSet();
}
} else if (word_range.from() >= argument_range.from() &&
word_range.to() <= argument_range.from()) {
result.SetElementsInBothSets();
result.SetElementsInFirstSet();
} else {
// There is overlap, and neither is a subrange of the other
result.SetElementsInFirstSet();
result.SetElementsInSecondSet();
result.SetElementsInBothSets();
}
if (result.NonTrivialIntersection()) {
// The result is as (im)precise as we can possibly make it.
return result;
}
// Progress the range(s) with minimal to-character.
uc16 word_to = word_range.to();
uc16 argument_to = argument_range.to();
if (argument_to <= word_to) {
j++;
if (j < range->length()) {
argument_range = range->at(j);
}
}
if (word_to <= argument_to) {
i += 2;
if (i < kWordRangeCount) {
word_range = CharacterRange(kWordRanges[i], kWordRanges[i + 1]);
}
}
}
// Check if anything wasn't compared in the loop.
if (i < kWordRangeCount) {
// word range contains something not in argument range.
result.SetElementsInSecondSet();
} else if (j < range->length()) {
// Argument range contains something not in word range.
result.SetElementsInFirstSet();
}
return result;
}
ZoneList<CharacterRange>* CharacterSet::ranges() {
if (ranges_ == NULL) {
ranges_ = new ZoneList<CharacterRange>(2);
CharacterRange::AddClassEscape(standard_set_type_, ranges_);
}
return ranges_;
}
// Move a number of elements in a zonelist to another position
// in the same list. Handles overlapping source and target areas.
static void MoveRanges(ZoneList<CharacterRange>* list,
int from,
int to,
int count) {
// Ranges are potentially overlapping.
if (from < to) {
for (int i = count - 1; i >= 0; i--) {
list->at(to + i) = list->at(from + i);
}
} else {
for (int i = 0; i < count; i++) {
list->at(to + i) = list->at(from + i);
}
}
}
static int InsertRangeInCanonicalList(ZoneList<CharacterRange>* list,
int count,
CharacterRange insert) {
// Inserts a range into list[0..count[, which must be sorted
// by from value and non-overlapping and non-adjacent, using at most
// list[0..count] for the result. Returns the number of resulting
// canonicalized ranges. Inserting a range may collapse existing ranges into
// fewer ranges, so the return value can be anything in the range 1..count+1.
uc16 from = insert.from();
uc16 to = insert.to();
int start_pos = 0;
int end_pos = count;
for (int i = count - 1; i >= 0; i--) {
CharacterRange current = list->at(i);
if (current.from() > to + 1) {
end_pos = i;
} else if (current.to() + 1 < from) {
start_pos = i + 1;
break;
}
}
// Inserted range overlaps, or is adjacent to, ranges at positions
// [start_pos..end_pos[. Ranges before start_pos or at or after end_pos are
// not affected by the insertion.
// If start_pos == end_pos, the range must be inserted before start_pos.
// if start_pos < end_pos, the entire range from start_pos to end_pos
// must be merged with the insert range.
if (start_pos == end_pos) {
// Insert between existing ranges at position start_pos.
if (start_pos < count) {
MoveRanges(list, start_pos, start_pos + 1, count - start_pos);
}
list->at(start_pos) = insert;
return count + 1;
}
if (start_pos + 1 == end_pos) {
// Replace single existing range at position start_pos.
CharacterRange to_replace = list->at(start_pos);
int new_from = Min(to_replace.from(), from);
int new_to = Max(to_replace.to(), to);
list->at(start_pos) = CharacterRange(new_from, new_to);
return count;
}
// Replace a number of existing ranges from start_pos to end_pos - 1.
// Move the remaining ranges down.
int new_from = Min(list->at(start_pos).from(), from);
int new_to = Max(list->at(end_pos - 1).to(), to);
if (end_pos < count) {
MoveRanges(list, end_pos, start_pos + 1, count - end_pos);
}
list->at(start_pos) = CharacterRange(new_from, new_to);
return count - (end_pos - start_pos) + 1;
}
void CharacterSet::Canonicalize() {
// Special/default classes are always considered canonical. The result
// of calling ranges() will be sorted.
if (ranges_ == NULL) return;
CharacterRange::Canonicalize(ranges_);
}
void CharacterRange::Canonicalize(ZoneList<CharacterRange>* character_ranges) {
if (character_ranges->length() <= 1) return;
// Check whether ranges are already canonical (increasing, non-overlapping,
// non-adjacent).
int n = character_ranges->length();
int max = character_ranges->at(0).to();
int i = 1;
while (i < n) {
CharacterRange current = character_ranges->at(i);
if (current.from() <= max + 1) {
break;
}
max = current.to();
i++;
}
// Canonical until the i'th range. If that's all of them, we are done.
if (i == n) return;
// The ranges at index i and forward are not canonicalized. Make them so by
// doing the equivalent of insertion sort (inserting each into the previous
// list, in order).
// Notice that inserting a range can reduce the number of ranges in the
// result due to combining of adjacent and overlapping ranges.
int read = i; // Range to insert.
int num_canonical = i; // Length of canonicalized part of list.
do {
num_canonical = InsertRangeInCanonicalList(character_ranges,
num_canonical,
character_ranges->at(read));
read++;
} while (read < n);
character_ranges->Rewind(num_canonical);
ASSERT(CharacterRange::IsCanonical(character_ranges));
}
// Utility function for CharacterRange::Merge. Adds a range at the end of
// a canonicalized range list, if necessary merging the range with the last
// range of the list.
static void AddRangeToSet(ZoneList<CharacterRange>* set, CharacterRange range) {
if (set == NULL) return;
ASSERT(set->length() == 0 || set->at(set->length() - 1).to() < range.from());
int n = set->length();
if (n > 0) {
CharacterRange lastRange = set->at(n - 1);
if (lastRange.to() == range.from() - 1) {
set->at(n - 1) = CharacterRange(lastRange.from(), range.to());
return;
}
}
set->Add(range);
}
static void AddRangeToSelectedSet(int selector,
ZoneList<CharacterRange>* first_set,
ZoneList<CharacterRange>* second_set,
ZoneList<CharacterRange>* intersection_set,
CharacterRange range) {
switch (selector) {
case kInsideFirst:
AddRangeToSet(first_set, range);
break;
case kInsideSecond:
AddRangeToSet(second_set, range);
break;
case kInsideBoth:
AddRangeToSet(intersection_set, range);
break;
}
}
void CharacterRange::Merge(ZoneList<CharacterRange>* first_set,
ZoneList<CharacterRange>* second_set,
ZoneList<CharacterRange>* first_set_only_out,
ZoneList<CharacterRange>* second_set_only_out,
ZoneList<CharacterRange>* both_sets_out) {
// Inputs are canonicalized.
ASSERT(CharacterRange::IsCanonical(first_set));
ASSERT(CharacterRange::IsCanonical(second_set));
// Outputs are empty, if applicable.
ASSERT(first_set_only_out == NULL || first_set_only_out->length() == 0);
ASSERT(second_set_only_out == NULL || second_set_only_out->length() == 0);
ASSERT(both_sets_out == NULL || both_sets_out->length() == 0);
// Merge sets by iterating through the lists in order of lowest "from" value,
// and putting intervals into one of three sets.
if (first_set->length() == 0) {
second_set_only_out->AddAll(*second_set);
return;
}
if (second_set->length() == 0) {
first_set_only_out->AddAll(*first_set);
return;
}
// Indices into input lists.
int i1 = 0;
int i2 = 0;
// Cache length of input lists.
int n1 = first_set->length();
int n2 = second_set->length();
// Current range. May be invalid if state is kInsideNone.
int from = 0;
int to = -1;
// Where current range comes from.
int state = kInsideNone;
while (i1 < n1 || i2 < n2) {
CharacterRange next_range;
int range_source;
if (i2 == n2 ||
(i1 < n1 && first_set->at(i1).from() < second_set->at(i2).from())) {
// Next smallest element is in first set.
next_range = first_set->at(i1++);
range_source = kInsideFirst;
} else {
// Next smallest element is in second set.
next_range = second_set->at(i2++);
range_source = kInsideSecond;
}
if (to < next_range.from()) {
// Ranges disjoint: |current| |next|
AddRangeToSelectedSet(state,
first_set_only_out,
second_set_only_out,
both_sets_out,
CharacterRange(from, to));
from = next_range.from();
to = next_range.to();
state = range_source;
} else {
if (from < next_range.from()) {
AddRangeToSelectedSet(state,
first_set_only_out,
second_set_only_out,
both_sets_out,
CharacterRange(from, next_range.from()-1));
}
if (to < next_range.to()) {
// Ranges overlap: |current|
// |next|
AddRangeToSelectedSet(state | range_source,
first_set_only_out,
second_set_only_out,
both_sets_out,
CharacterRange(next_range.from(), to));
from = to + 1;
to = next_range.to();
state = range_source;
} else {
// Range included: |current| , possibly ending at same character.
// |next|
AddRangeToSelectedSet(
state | range_source,
first_set_only_out,
second_set_only_out,
both_sets_out,
CharacterRange(next_range.from(), next_range.to()));
from = next_range.to() + 1;
// If ranges end at same character, both ranges are consumed completely.
if (next_range.to() == to) state = kInsideNone;
}
}
}
AddRangeToSelectedSet(state,
first_set_only_out,
second_set_only_out,
both_sets_out,
CharacterRange(from, to));
}
void CharacterRange::Negate(ZoneList<CharacterRange>* ranges,
ZoneList<CharacterRange>* negated_ranges) {
ASSERT(CharacterRange::IsCanonical(ranges));
ASSERT_EQ(0, negated_ranges->length());
int range_count = ranges->length();
uc16 from = 0;
int i = 0;
if (range_count > 0 && ranges->at(0).from() == 0) {
from = ranges->at(0).to();
i = 1;
}
while (i < range_count) {
CharacterRange range = ranges->at(i);
negated_ranges->Add(CharacterRange(from + 1, range.from() - 1));
from = range.to();
i++;
}
if (from < String::kMaxUC16CharCode) {
negated_ranges->Add(CharacterRange(from + 1, String::kMaxUC16CharCode));
}
}
// -------------------------------------------------------------------
// Interest propagation
RegExpNode* RegExpNode::TryGetSibling(NodeInfo* info) {
for (int i = 0; i < siblings_.length(); i++) {
RegExpNode* sibling = siblings_.Get(i);
if (sibling->info()->Matches(info))
return sibling;
}
return NULL;
}
RegExpNode* RegExpNode::EnsureSibling(NodeInfo* info, bool* cloned) {
ASSERT_EQ(false, *cloned);
siblings_.Ensure(this);
RegExpNode* result = TryGetSibling(info);
if (result != NULL) return result;
result = this->Clone();
NodeInfo* new_info = result->info();
new_info->ResetCompilationState();
new_info->AddFromPreceding(info);
AddSibling(result);
*cloned = true;
return result;
}
template <class C>
static RegExpNode* PropagateToEndpoint(C* node, NodeInfo* info) {
NodeInfo full_info(*node->info());
full_info.AddFromPreceding(info);
bool cloned = false;
return RegExpNode::EnsureSibling(node, &full_info, &cloned);
}
// -------------------------------------------------------------------
// Splay tree
OutSet* OutSet::Extend(unsigned value) {
if (Get(value))
return this;
if (successors() != NULL) {
for (int i = 0; i < successors()->length(); i++) {
OutSet* successor = successors()->at(i);
if (successor->Get(value))
return successor;
}
} else {
successors_ = new ZoneList<OutSet*>(2);
}
OutSet* result = new OutSet(first_, remaining_);
result->Set(value);
successors()->Add(result);
return result;
}
void OutSet::Set(unsigned value) {
if (value < kFirstLimit) {
first_ |= (1 << value);
} else {
if (remaining_ == NULL)
remaining_ = new ZoneList<unsigned>(1);
if (remaining_->is_empty() || !remaining_->Contains(value))
remaining_->Add(value);
}
}
bool OutSet::Get(unsigned value) {
if (value < kFirstLimit) {
return (first_ & (1 << value)) != 0;
} else if (remaining_ == NULL) {
return false;
} else {
return remaining_->Contains(value);
}
}
const uc16 DispatchTable::Config::kNoKey = unibrow::Utf8::kBadChar;
void DispatchTable::AddRange(CharacterRange full_range, int value) {
CharacterRange current = full_range;
if (tree()->is_empty()) {
// If this is the first range we just insert into the table.
ZoneSplayTree<Config>::Locator loc;
ASSERT_RESULT(tree()->Insert(current.from(), &loc));
loc.set_value(Entry(current.from(), current.to(), empty()->Extend(value)));
return;
}
// First see if there is a range to the left of this one that
// overlaps.
ZoneSplayTree<Config>::Locator loc;
if (tree()->FindGreatestLessThan(current.from(), &loc)) {
Entry* entry = &loc.value();
// If we've found a range that overlaps with this one, and it
// starts strictly to the left of this one, we have to fix it
// because the following code only handles ranges that start on
// or after the start point of the range we're adding.
if (entry->from() < current.from() && entry->to() >= current.from()) {
// Snap the overlapping range in half around the start point of
// the range we're adding.
CharacterRange left(entry->from(), current.from() - 1);
CharacterRange right(current.from(), entry->to());
// The left part of the overlapping range doesn't overlap.
// Truncate the whole entry to be just the left part.
entry->set_to(left.to());
// The right part is the one that overlaps. We add this part
// to the map and let the next step deal with merging it with
// the range we're adding.
ZoneSplayTree<Config>::Locator loc;
ASSERT_RESULT(tree()->Insert(right.from(), &loc));
loc.set_value(Entry(right.from(),
right.to(),
entry->out_set()));
}
}
while (current.is_valid()) {
if (tree()->FindLeastGreaterThan(current.from(), &loc) &&
(loc.value().from() <= current.to()) &&
(loc.value().to() >= current.from())) {
Entry* entry = &loc.value();
// We have overlap. If there is space between the start point of
// the range we're adding and where the overlapping range starts
// then we have to add a range covering just that space.
if (current.from() < entry->from()) {
ZoneSplayTree<Config>::Locator ins;
ASSERT_RESULT(tree()->Insert(current.from(), &ins));
ins.set_value(Entry(current.from(),
entry->from() - 1,
empty()->Extend(value)));
current.set_from(entry->from());
}
ASSERT_EQ(current.from(), entry->from());
// If the overlapping range extends beyond the one we want to add
// we have to snap the right part off and add it separately.
if (entry->to() > current.to()) {
ZoneSplayTree<Config>::Locator ins;
ASSERT_RESULT(tree()->Insert(current.to() + 1, &ins));
ins.set_value(Entry(current.to() + 1,
entry->to(),
entry->out_set()));
entry->set_to(current.to());
}
ASSERT(entry->to() <= current.to());
// The overlapping range is now completely contained by the range
// we're adding so we can just update it and move the start point
// of the range we're adding just past it.
entry->AddValue(value);
// Bail out if the last interval ended at 0xFFFF since otherwise
// adding 1 will wrap around to 0.
if (entry->to() == String::kMaxUC16CharCode)
break;
ASSERT(entry->to() + 1 > current.from());
current.set_from(entry->to() + 1);
} else {
// There is no overlap so we can just add the range
ZoneSplayTree<Config>::Locator ins;
ASSERT_RESULT(tree()->Insert(current.from(), &ins));
ins.set_value(Entry(current.from(),
current.to(),
empty()->Extend(value)));
break;
}
}
}
OutSet* DispatchTable::Get(uc16 value) {
ZoneSplayTree<Config>::Locator loc;
if (!tree()->FindGreatestLessThan(value, &loc))
return empty();
Entry* entry = &loc.value();
if (value <= entry->to())
return entry->out_set();
else
return empty();
}
// -------------------------------------------------------------------
// Analysis
void Analysis::EnsureAnalyzed(RegExpNode* that) {
StackLimitCheck check(Isolate::Current());
if (check.HasOverflowed()) {
fail("Stack overflow");
return;
}
if (that->info()->been_analyzed || that->info()->being_analyzed)
return;
that->info()->being_analyzed = true;
that->Accept(this);
that->info()->being_analyzed = false;
that->info()->been_analyzed = true;
}
void Analysis::VisitEnd(EndNode* that) {
// nothing to do
}
void TextNode::CalculateOffsets() {
int element_count = elements()->length();
// Set up the offsets of the elements relative to the start. This is a fixed
// quantity since a TextNode can only contain fixed-width things.
int cp_offset = 0;
for (int i = 0; i < element_count; i++) {
TextElement& elm = elements()->at(i);
elm.cp_offset = cp_offset;
if (elm.type == TextElement::ATOM) {
cp_offset += elm.data.u_atom->data().length();
} else {
cp_offset++;
}
}
}
void Analysis::VisitText(TextNode* that) {
if (ignore_case_) {
that->MakeCaseIndependent(is_ascii_);
}
EnsureAnalyzed(that->on_success());
if (!has_failed()) {
that->CalculateOffsets();
}
}
void Analysis::VisitAction(ActionNode* that) {
RegExpNode* target = that->on_success();
EnsureAnalyzed(target);
if (!has_failed()) {
// If the next node is interested in what it follows then this node
// has to be interested too so it can pass the information on.
that->info()->AddFromFollowing(target->info());
}
}
void Analysis::VisitChoice(ChoiceNode* that) {
NodeInfo* info = that->info();
for (int i = 0; i < that->alternatives()->length(); i++) {
RegExpNode* node = that->alternatives()->at(i).node();
EnsureAnalyzed(node);
if (has_failed()) return;
// Anything the following nodes need to know has to be known by
// this node also, so it can pass it on.
info->AddFromFollowing(node->info());
}
}
void Analysis::VisitLoopChoice(LoopChoiceNode* that) {
NodeInfo* info = that->info();
for (int i = 0; i < that->alternatives()->length(); i++) {
RegExpNode* node = that->alternatives()->at(i).node();
if (node != that->loop_node()) {
EnsureAnalyzed(node);
if (has_failed()) return;
info->AddFromFollowing(node->info());
}
}
// Check the loop last since it may need the value of this node
// to get a correct result.
EnsureAnalyzed(that->loop_node());
if (!has_failed()) {
info->AddFromFollowing(that->loop_node()->info());
}
}
void Analysis::VisitBackReference(BackReferenceNode* that) {
EnsureAnalyzed(that->on_success());
}
void Analysis::VisitAssertion(AssertionNode* that) {
EnsureAnalyzed(that->on_success());
AssertionNode::AssertionNodeType type = that->type();
if (type == AssertionNode::AT_BOUNDARY ||
type == AssertionNode::AT_NON_BOUNDARY) {
// Check if the following character is known to be a word character
// or known to not be a word character.
ZoneList<CharacterRange>* following_chars = that->FirstCharacterSet();
CharacterRange::Canonicalize(following_chars);
SetRelation word_relation =
CharacterRange::WordCharacterRelation(following_chars);
if (word_relation.Disjoint()) {
// Includes the case where following_chars is empty (e.g., end-of-input).
// Following character is definitely *not* a word character.
type = (type == AssertionNode::AT_BOUNDARY) ?
AssertionNode::AFTER_WORD_CHARACTER :
AssertionNode::AFTER_NONWORD_CHARACTER;
that->set_type(type);
} else if (word_relation.ContainedIn()) {
// Following character is definitely a word character.
type = (type == AssertionNode::AT_BOUNDARY) ?
AssertionNode::AFTER_NONWORD_CHARACTER :
AssertionNode::AFTER_WORD_CHARACTER;
that->set_type(type);
}
}
}
ZoneList<CharacterRange>* RegExpNode::FirstCharacterSet() {
if (first_character_set_ == NULL) {
if (ComputeFirstCharacterSet(kFirstCharBudget) < 0) {
// If we can't find an exact solution within the budget, we
// set the value to the set of every character, i.e., all characters
// are possible.
ZoneList<CharacterRange>* all_set = new ZoneList<CharacterRange>(1);
all_set->Add(CharacterRange::Everything());
first_character_set_ = all_set;
}
}
return first_character_set_;
}
int RegExpNode::ComputeFirstCharacterSet(int budget) {
// Default behavior is to not be able to determine the first character.
return kComputeFirstCharacterSetFail;
}
int LoopChoiceNode::ComputeFirstCharacterSet(int budget) {
budget--;
if (budget >= 0) {
// Find loop min-iteration. It's the value of the guarded choice node
// with a GEQ guard, if any.
int min_repetition = 0;
for (int i = 0; i <= 1; i++) {
GuardedAlternative alternative = alternatives()->at(i);
ZoneList<Guard*>* guards = alternative.guards();
if (guards != NULL && guards->length() > 0) {
Guard* guard = guards->at(0);
if (guard->op() == Guard::GEQ) {
min_repetition = guard->value();
break;
}
}
}
budget = loop_node()->ComputeFirstCharacterSet(budget);
if (budget >= 0) {
ZoneList<CharacterRange>* character_set =
loop_node()->first_character_set();
if (body_can_be_zero_length() || min_repetition == 0) {
budget = continue_node()->ComputeFirstCharacterSet(budget);
if (budget < 0) return budget;
ZoneList<CharacterRange>* body_set =
continue_node()->first_character_set();
ZoneList<CharacterRange>* union_set =
new ZoneList<CharacterRange>(Max(character_set->length(),
body_set->length()));
CharacterRange::Merge(character_set,
body_set,
union_set,
union_set,
union_set);
character_set = union_set;
}
set_first_character_set(character_set);
}
}
return budget;
}
int NegativeLookaheadChoiceNode::ComputeFirstCharacterSet(int budget) {
budget--;
if (budget >= 0) {
GuardedAlternative successor = this->alternatives()->at(1);
RegExpNode* successor_node = successor.node();
budget = successor_node->ComputeFirstCharacterSet(budget);
if (budget >= 0) {
set_first_character_set(successor_node->first_character_set());
}
}
return budget;
}
// The first character set of an EndNode is unknowable. Just use the
// default implementation that fails and returns all characters as possible.
int AssertionNode::ComputeFirstCharacterSet(int budget) {
budget -= 1;
if (budget >= 0) {
switch (type_) {
case AT_END: {
set_first_character_set(new ZoneList<CharacterRange>(0));
break;
}
case AT_START:
case AT_BOUNDARY:
case AT_NON_BOUNDARY:
case AFTER_NEWLINE:
case AFTER_NONWORD_CHARACTER:
case AFTER_WORD_CHARACTER: {
ASSERT_NOT_NULL(on_success());
budget = on_success()->ComputeFirstCharacterSet(budget);
if (budget >= 0) {
set_first_character_set(on_success()->first_character_set());
}
break;
}
}
}
return budget;
}
int ActionNode::ComputeFirstCharacterSet(int budget) {
if (type_ == POSITIVE_SUBMATCH_SUCCESS) return kComputeFirstCharacterSetFail;
budget--;
if (budget >= 0) {
ASSERT_NOT_NULL(on_success());
budget = on_success()->ComputeFirstCharacterSet(budget);
if (budget >= 0) {
set_first_character_set(on_success()->first_character_set());
}
}
return budget;
}
int BackReferenceNode::ComputeFirstCharacterSet(int budget) {
// We don't know anything about the first character of a backreference
// at this point.
// The potential first characters are the first characters of the capture,
// and the first characters of the on_success node, depending on whether the
// capture can be empty and whether it is known to be participating or known
// not to be.
return kComputeFirstCharacterSetFail;
}
int TextNode::ComputeFirstCharacterSet(int budget) {
budget--;
if (budget >= 0) {
ASSERT_NE(0, elements()->length());
TextElement text = elements()->at(0);
if (text.type == TextElement::ATOM) {
RegExpAtom* atom = text.data.u_atom;
ASSERT_NE(0, atom->length());
uc16 first_char = atom->data()[0];
ZoneList<CharacterRange>* range = new ZoneList<CharacterRange>(1);
range->Add(CharacterRange(first_char, first_char));
set_first_character_set(range);
} else {
ASSERT(text.type == TextElement::CHAR_CLASS);
RegExpCharacterClass* char_class = text.data.u_char_class;
ZoneList<CharacterRange>* ranges = char_class->ranges();
// TODO(lrn): Canonicalize ranges when they are created
// instead of waiting until now.
CharacterRange::Canonicalize(ranges);
if (char_class->is_negated()) {
int length = ranges->length();
int new_length = length + 1;
if (length > 0) {
if (ranges->at(0).from() == 0) new_length--;
if (ranges->at(length - 1).to() == String::kMaxUC16CharCode) {
new_length--;
}
}
ZoneList<CharacterRange>* negated_ranges =
new ZoneList<CharacterRange>(new_length);
CharacterRange::Negate(ranges, negated_ranges);
set_first_character_set(negated_ranges);
} else {
set_first_character_set(ranges);
}
}
}
return budget;
}
// -------------------------------------------------------------------
// Dispatch table construction
void DispatchTableConstructor::VisitEnd(EndNode* that) {
AddRange(CharacterRange::Everything());
}
void DispatchTableConstructor::BuildTable(ChoiceNode* node) {
node->set_being_calculated(true);
ZoneList<GuardedAlternative>* alternatives = node->alternatives();
for (int i = 0; i < alternatives->length(); i++) {
set_choice_index(i);
alternatives->at(i).node()->Accept(this);
}
node->set_being_calculated(false);
}
class AddDispatchRange {
public:
explicit AddDispatchRange(DispatchTableConstructor* constructor)
: constructor_(constructor) { }
void Call(uc32 from, DispatchTable::Entry entry);
private:
DispatchTableConstructor* constructor_;
};
void AddDispatchRange::Call(uc32 from, DispatchTable::Entry entry) {
CharacterRange range(from, entry.to());
constructor_->AddRange(range);
}
void DispatchTableConstructor::VisitChoice(ChoiceNode* node) {
if (node->being_calculated())
return;
DispatchTable* table = node->GetTable(ignore_case_);
AddDispatchRange adder(this);
table->ForEach(&adder);
}
void DispatchTableConstructor::VisitBackReference(BackReferenceNode* that) {
// TODO(160): Find the node that we refer back to and propagate its start
// set back to here. For now we just accept anything.
AddRange(CharacterRange::Everything());
}
void DispatchTableConstructor::VisitAssertion(AssertionNode* that) {
RegExpNode* target = that->on_success();
target->Accept(this);
}
static int CompareRangeByFrom(const CharacterRange* a,
const CharacterRange* b) {
return Compare<uc16>(a->from(), b->from());
}
void DispatchTableConstructor::AddInverse(ZoneList<CharacterRange>* ranges) {
ranges->Sort(CompareRangeByFrom);
uc16 last = 0;
for (int i = 0; i < ranges->length(); i++) {
CharacterRange range = ranges->at(i);
if (last < range.from())
AddRange(CharacterRange(last, range.from() - 1));
if (range.to() >= last) {
if (range.to() == String::kMaxUC16CharCode) {
return;
} else {
last = range.to() + 1;
}
}
}
AddRange(CharacterRange(last, String::kMaxUC16CharCode));
}
void DispatchTableConstructor::VisitText(TextNode* that) {
TextElement elm = that->elements()->at(0);
switch (elm.type) {
case TextElement::ATOM: {
uc16 c = elm.data.u_atom->data()[0];
AddRange(CharacterRange(c, c));
break;
}
case TextElement::CHAR_CLASS: {
RegExpCharacterClass* tree = elm.data.u_char_class;
ZoneList<CharacterRange>* ranges = tree->ranges();
if (tree->is_negated()) {
AddInverse(ranges);
} else {
for (int i = 0; i < ranges->length(); i++)
AddRange(ranges->at(i));
}
break;
}
default: {
UNIMPLEMENTED();
}
}
}
void DispatchTableConstructor::VisitAction(ActionNode* that) {
RegExpNode* target = that->on_success();
target->Accept(this);
}
RegExpEngine::CompilationResult RegExpEngine::Compile(RegExpCompileData* data,
bool ignore_case,
bool is_multiline,
Handle<String> pattern,
bool is_ascii) {
if ((data->capture_count + 1) * 2 - 1 > RegExpMacroAssembler::kMaxRegister) {
return IrregexpRegExpTooBig();
}
RegExpCompiler compiler(data->capture_count, ignore_case, is_ascii);
// Wrap the body of the regexp in capture #0.
RegExpNode* captured_body = RegExpCapture::ToNode(data->tree,
0,
&compiler,
compiler.accept());
RegExpNode* node = captured_body;
bool is_end_anchored = data->tree->IsAnchoredAtEnd();
bool is_start_anchored = data->tree->IsAnchoredAtStart();
int max_length = data->tree->max_match();
if (!is_start_anchored) {
// Add a .*? at the beginning, outside the body capture, unless
// this expression is anchored at the beginning.
RegExpNode* loop_node =
RegExpQuantifier::ToNode(0,
RegExpTree::kInfinity,
false,
new RegExpCharacterClass('*'),
&compiler,
captured_body,
data->contains_anchor);
if (data->contains_anchor) {
// Unroll loop once, to take care of the case that might start
// at the start of input.
ChoiceNode* first_step_node = new ChoiceNode(2);
first_step_node->AddAlternative(GuardedAlternative(captured_body));
first_step_node->AddAlternative(GuardedAlternative(
new TextNode(new RegExpCharacterClass('*'), loop_node)));
node = first_step_node;
} else {
node = loop_node;
}
}
data->node = node;
Analysis analysis(ignore_case, is_ascii);
analysis.EnsureAnalyzed(node);
if (analysis.has_failed()) {
const char* error_message = analysis.error_message();
return CompilationResult(error_message);
}
// Create the correct assembler for the architecture.
#ifndef V8_INTERPRETED_REGEXP
// Native regexp implementation.
NativeRegExpMacroAssembler::Mode mode =
is_ascii ? NativeRegExpMacroAssembler::ASCII
: NativeRegExpMacroAssembler::UC16;
#if V8_TARGET_ARCH_IA32
RegExpMacroAssemblerIA32 macro_assembler(mode, (data->capture_count + 1) * 2);
#elif V8_TARGET_ARCH_X64
RegExpMacroAssemblerX64 macro_assembler(mode, (data->capture_count + 1) * 2);
#elif V8_TARGET_ARCH_ARM
RegExpMacroAssemblerARM macro_assembler(mode, (data->capture_count + 1) * 2);
#elif V8_TARGET_ARCH_MIPS
RegExpMacroAssemblerMIPS macro_assembler(mode, (data->capture_count + 1) * 2);
#endif
#else // V8_INTERPRETED_REGEXP
// Interpreted regexp implementation.
EmbeddedVector<byte, 1024> codes;
RegExpMacroAssemblerIrregexp macro_assembler(codes);
#endif // V8_INTERPRETED_REGEXP
// Inserted here, instead of in Assembler, because it depends on information
// in the AST that isn't replicated in the Node structure.
static const int kMaxBacksearchLimit = 1024;
if (is_end_anchored &&
!is_start_anchored &&
max_length < kMaxBacksearchLimit) {
macro_assembler.SetCurrentPositionFromEnd(max_length);
}
return compiler.Assemble(&macro_assembler,
node,
data->capture_count,
pattern);
}
}} // namespace v8::internal
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