[regexp] Add dedicated flags for printing regexp code and bytecode

Printing regexp code used to behind the generic --print-code flag, but
there was no way to distinguish between irregexp-generated code; and
printing regexp bytecode was not supported at all (the
--trace-regexp-bytecodes flag *did* exist, but prints the execution
trace at runtime and not the generated bytecode sequence).

This CL adds two new flags:

--print-regexp-code
--print-regexp-bytecode

Regexp code is no longer printed as part of --print-code.

Example output for --print-regexp-bytecode:

generated bytecode for regexp pattern: .(?<!^.)
0x1ddcc614cbd0     0  PUSH_BT, 02, 00, 00, 00, c0, 00, 00, 00 .......
0x1ddcc614cbd8     8  LOAD_CURRENT_CHAR, 11, 00, 00, 00, b0, 00, 00, 00 .......
0x1ddcc614cbe0    10  CHECK_CHAR, 18, 0a, 00, 00, b0, 00, 00, 00 .......
0x1ddcc614cbe8    18  CHECK_CHAR, 18, 0d, 00, 00, b0, 00, 00, 00 .......
0x1ddcc614cbf0    20  PUSH_CP, 01, 00, 00, 00 ...

Bug: chromium:996391
Change-Id: I731defbd7cf9ed29753a39bb1d7205dc136ca950
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1773249
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63442}

src/flags/flag-definitions.h

@@ -1514,7 +1514,6 @@ DEFINE_BOOL(trace_elements_transitions, false, "trace elements transitions")
 DEFINE_BOOL(trace_creation_allocation_sites, false,
             "trace the creation of allocation sites")
 
-// codegen-ia32.cc / codegen-arm.cc
 DEFINE_BOOL(print_code, false, "print generated code")
 DEFINE_BOOL(print_opt_code, false, "print optimized code")
 DEFINE_STRING(print_opt_code_filter, "*", "filter for printing optimized code")
@@ -1522,6 +1521,8 @@ DEFINE_BOOL(print_code_verbose, false, "print more information for code")
 DEFINE_BOOL(print_builtin_code, false, "print generated code for builtins")
 DEFINE_STRING(print_builtin_code_filter, "*",
               "filter for printing builtin code")
+DEFINE_BOOL(print_regexp_code, false, "print generated regexp code")
+DEFINE_BOOL(print_regexp_bytecode, false, "print generated regexp bytecode")
 DEFINE_BOOL(print_builtin_size, false, "print code size for builtins")
 
 #ifdef ENABLE_DISASSEMBLER
@@ -1538,6 +1539,7 @@ DEFINE_IMPLICATION(print_all_code, print_code)
 DEFINE_IMPLICATION(print_all_code, print_opt_code)
 DEFINE_IMPLICATION(print_all_code, print_code_verbose)
 DEFINE_IMPLICATION(print_all_code, print_builtin_code)
+DEFINE_IMPLICATION(print_all_code, print_regexp_code)
 DEFINE_IMPLICATION(print_all_code, code_comments)
 #endif
 

src/regexp/regexp-bytecodes.h

@@ -5,6 +5,8 @@
 #ifndef V8_REGEXP_REGEXP_BYTECODES_H_
 #define V8_REGEXP_REGEXP_BYTECODES_H_
 
+#include "src/base/macros.h"
+
 namespace v8 {
 namespace internal {
 
@@ -70,14 +72,40 @@ const int BYTECODE_SHIFT = 8;
   V(SET_CURRENT_POSITION_FROM_END, 51, 4) /* bc8 idx24 */                      \
   V(CHECK_CURRENT_POSITION, 52, 8)        /* bc8 idx24 addr32 */
 
-#define DECLARE_BYTECODES(name, code, length) static const int BC_##name = code;
+#define COUNT(...) +1
+static constexpr int kRegExpBytecodeCount = BYTECODE_ITERATOR(COUNT);
+#undef COUNT
+
+// Just making sure we assigned values above properly. They should be
+// contiguous, strictly increasing, and start at 0.
+// TODO(jgruber): Do not explicitly assign values, instead generate them
+// implicitly from the list order.
+STATIC_ASSERT(kRegExpBytecodeCount == 53);
+
+#define DECLARE_BYTECODES(name, code, length) \
+  static constexpr int BC_##name = code;
 BYTECODE_ITERATOR(DECLARE_BYTECODES)
 #undef DECLARE_BYTECODES
 
-#define DECLARE_BYTECODE_LENGTH(name, code, length) \
+static constexpr int kRegExpBytecodeLengths[] = {
-  static const int BC_##name##_LENGTH = length;
+#define DECLARE_BYTECODE_LENGTH(name, code, length) length,
-BYTECODE_ITERATOR(DECLARE_BYTECODE_LENGTH)
+    BYTECODE_ITERATOR(DECLARE_BYTECODE_LENGTH)
 #undef DECLARE_BYTECODE_LENGTH
+};
+
+inline constexpr int RegExpBytecodeLength(int bytecode) {
+  return kRegExpBytecodeLengths[bytecode];
+}
+
+static const char* const kRegExpBytecodeNames[] = {
+#define DECLARE_BYTECODE_NAME(name, ...) #name,
+    BYTECODE_ITERATOR(DECLARE_BYTECODE_NAME)
+#undef DECLARE_BYTECODE_NAME
+};
+
+inline const char* RegExpBytecodeName(int bytecode) {
+  return kRegExpBytecodeNames[bytecode];
+}
 
 }  // namespace internal
 }  // namespace v8

src/regexp/regexp-compiler.cc

@@ -5,13 +5,11 @@
 #include "src/regexp/regexp-compiler.h"
 
 #include "src/base/safe_conversions.h"
-#include "src/diagnostics/code-tracer.h"
 #include "src/execution/isolate.h"
 #include "src/objects/objects-inl.h"
 #include "src/regexp/regexp-macro-assembler-arch.h"
 #include "src/regexp/regexp-macro-assembler-tracer.h"
 #include "src/strings/unicode-inl.h"
-#include "src/utils/ostreams.h"
 #include "src/zone/zone-list-inl.h"
 
 #ifdef V8_INTL_SUPPORT
@@ -273,13 +271,7 @@ RegExpCompiler::CompilationResult RegExpCompiler::Assemble(
   Handle<HeapObject> code = macro_assembler_->GetCode(pattern);
   isolate->IncreaseTotalRegexpCodeGenerated(code->Size());
   work_list_ = nullptr;
-#ifdef ENABLE_DISASSEMBLER
+
-  if (FLAG_print_code && code->IsCode()) {
-    CodeTracer::Scope trace_scope(isolate->GetCodeTracer());
-    OFStream os(trace_scope.file());
-    Handle<Code>::cast(code)->Disassemble(pattern->ToCString().get(), os);
-  }
-#endif
 #ifdef DEBUG
   if (FLAG_trace_regexp_assembler) {
     delete macro_assembler_;

src/regexp/regexp-interpreter.cc

@@ -30,9 +30,10 @@
 namespace v8 {
 namespace internal {
 
-static bool BackRefMatchesNoCase(Isolate* isolate, int from, int current,
+namespace {
-                                 int len, Vector<const uc16> subject,
+
-                                 bool unicode) {
+bool BackRefMatchesNoCase(Isolate* isolate, int from, int current, int len,
+                          Vector<const uc16> subject, bool unicode) {
   Address offset_a =
       reinterpret_cast<Address>(const_cast<uc16*>(&subject.at(from)));
   Address offset_b =
@@ -42,9 +43,8 @@ static bool BackRefMatchesNoCase(Isolate* isolate, int from, int current,
              offset_a, offset_b, length, unicode ? nullptr : isolate) == 1;
 }
 
-static bool BackRefMatchesNoCase(Isolate* isolate, int from, int current,
+bool BackRefMatchesNoCase(Isolate* isolate, int from, int current, int len,
-                                 int len, Vector<const uint8_t> subject,
+                          Vector<const uint8_t> subject, bool unicode) {
-                                 bool unicode) {
   // For Latin1 characters the unicode flag makes no difference.
   for (int i = 0; i < len; i++) {
     unsigned int old_char = subject[from++];
@@ -63,42 +63,48 @@ static bool BackRefMatchesNoCase(Isolate* isolate, int from, int current,
   return true;
 }
 
+void DisassembleSingleBytecode(const byte* code_base, const byte* pc) {
+  PrintF("%s", RegExpBytecodeName(*pc));
+
+  // Args and the bytecode as hex.
+  for (int i = 0; i < RegExpBytecodeLength(*pc); i++) {
+    PrintF(", %02x", pc[i]);
+  }
+  PrintF(" ");
+
+  // Args as ascii.
+  for (int i = 1; i < RegExpBytecodeLength(*pc); i++) {
+    unsigned char b = pc[i];
+    PrintF("%c", std::isprint(b) ? b : '.');
+  }
+  PrintF("\n");
+}
+
 #ifdef DEBUG
-static void TraceInterpreter(const byte* code_base, const byte* pc,
+void MaybeTraceInterpreter(const byte* code_base, const byte* pc,
-                             int stack_depth, int current_position,
+                           int stack_depth, int current_position,
-                             uint32_t current_char, int bytecode_length,
+                           uint32_t current_char, int bytecode_length,
-                             const char* bytecode_name) {
+                           const char* bytecode_name) {
   if (FLAG_trace_regexp_bytecodes) {
-    bool printable = (current_char < 127 && current_char >= 32);
+    const bool printable = std::isprint(current_char);
     const char* format =
         printable
-            ? "pc = %02x, sp = %d, curpos = %d, curchar = %08x (%c), bc = %s"
+            ? "pc = %02x, sp = %d, curpos = %d, curchar = %08x (%c), bc = "
-            : "pc = %02x, sp = %d, curpos = %d, curchar = %08x .%c., bc = %s";
+            : "pc = %02x, sp = %d, curpos = %d, curchar = %08x .%c., bc = ";
     PrintF(format, pc - code_base, stack_depth, current_position, current_char,
-           printable ? current_char : '.', bytecode_name);
+           printable ? current_char : '.');
-    for (int i = 0; i < bytecode_length; i++) {
+
-      printf(", %02x", pc[i]);
+    DisassembleSingleBytecode(code_base, pc);
-    }
-    printf(" ");
-    for (int i = 1; i < bytecode_length; i++) {
-      unsigned char b = pc[i];
-      if (b < 127 && b >= 32) {
-        printf("%c", b);
-      } else {
-        printf(".");
-      }
-    }
-    printf("\n");
   }
 }
 #endif  // DEBUG
 
-static int32_t Load32Aligned(const byte* pc) {
+int32_t Load32Aligned(const byte* pc) {
   DCHECK_EQ(0, reinterpret_cast<intptr_t>(pc) & 3);
   return *reinterpret_cast<const int32_t*>(pc);
 }
 
-static int32_t Load16Aligned(const byte* pc) {
+int32_t Load16Aligned(const byte* pc) {
   DCHECK_EQ(0, reinterpret_cast<intptr_t>(pc) & 1);
   return *reinterpret_cast<const uint16_t*>(pc);
 }
@@ -140,8 +146,6 @@ class BacktrackStack {
   DISALLOW_COPY_AND_ASSIGN(BacktrackStack);
 };
 
-namespace {
-
 IrregexpInterpreter::Result StackOverflow(Isolate* isolate,
                                           RegExp::CallOrigin call_origin) {
   CHECK(call_origin == RegExp::CallOrigin::kFromRuntime);
@@ -268,18 +272,18 @@ IrregexpInterpreter::Result HandleInterrupts(
 // don't hit the cache and have to fetch the next handler address from physical
 // memory, instructions between ADVANCE/SET_PC_FROM_OFFSET and DISPATCH can
 // potentially be executed unconditionally, reducing memory stall.
-#define ADVANCE(name)                \
+#define ADVANCE(name)                             \
-  next_pc = pc + BC_##name##_LENGTH; \
+  next_pc = pc + RegExpBytecodeLength(BC_##name); \
   DECODE()
 #define SET_PC_FROM_OFFSET(offset) \
   next_pc = code_base + offset;    \
   DECODE()
 
 #ifdef DEBUG
-#define BYTECODE(name)                                                         \
+#define BYTECODE(name)                                                \
-  BC_LABEL(name)                                                               \
+  BC_LABEL(name)                                                      \
-  TraceInterpreter(code_base, pc, backtrack_stack.sp(), current, current_char, \
+  MaybeTraceInterpreter(code_base, pc, backtrack_stack.sp(), current, \
-                   BC_##name##_LENGTH, #name);
+                        current_char, RegExpBytecodeLength(BC_##name), #name);
 #else
 #define BYTECODE(name) BC_LABEL(name)
 #endif  // DEBUG
@@ -779,6 +783,25 @@ IrregexpInterpreter::Result RawMatch(Isolate* isolate, ByteArray code_array,
 
 }  // namespace
 
+// static
+void IrregexpInterpreter::Disassemble(ByteArray byte_array,
+                                      const std::string& pattern) {
+  DisallowHeapAllocation no_gc;
+
+  PrintF("[generated bytecode for regexp pattern: '%s']\n", pattern.c_str());
+
+  const byte* const code_base = byte_array.GetDataStartAddress();
+  const int byte_array_length = byte_array.length();
+  ptrdiff_t offset = 0;
+
+  while (offset < byte_array_length) {
+    const byte* const pc = code_base + offset;
+    PrintF("%p  %4" V8PRIxPTRDIFF "  ", pc, offset);
+    DisassembleSingleBytecode(code_base, pc);
+    offset += RegExpBytecodeLength(*pc);
+  }
+}
+
 // static
 IrregexpInterpreter::Result IrregexpInterpreter::Match(
     Isolate* isolate, JSRegExp regexp, String subject_string, int* registers,

src/regexp/regexp-interpreter.h

@@ -41,6 +41,8 @@ class V8_EXPORT_PRIVATE IrregexpInterpreter : public AllStatic {
                               int registers_length, int start_position,
                               RegExp::CallOrigin call_origin);
 
+  static void Disassemble(ByteArray byte_array, const std::string& pattern);
+
  private:
   static Result Match(Isolate* isolate, JSRegExp regexp, String subject_string,
                       int* registers, int registers_length, int start_position,

src/regexp/regexp.cc

@@ -5,6 +5,7 @@
 #include "src/regexp/regexp.h"
 
 #include "src/codegen/compilation-cache.h"
+#include "src/diagnostics/code-tracer.h"
 #include "src/heap/heap-inl.h"
 #include "src/objects/js-regexp-inl.h"
 #include "src/regexp/regexp-bytecode-generator.h"
@@ -14,6 +15,7 @@
 #include "src/regexp/regexp-macro-assembler-arch.h"
 #include "src/regexp/regexp-parser.h"
 #include "src/strings/string-search.h"
+#include "src/utils/ostreams.h"
 
 namespace v8 {
 namespace internal {
@@ -572,14 +574,15 @@ MaybeHandle<Object> RegExpImpl::IrregexpExec(
 
   subject = String::Flatten(isolate, subject);
 
-  // Prepare space for the return values.
 #ifdef DEBUG
-  if (FLAG_regexp_interpret_all && FLAG_trace_regexp_bytecodes) {
+  if (FLAG_trace_regexp_bytecodes && regexp->ShouldProduceBytecode()) {
     String pattern = regexp->Pattern();
     PrintF("\n\nRegexp match:   /%s/\n\n", pattern.ToCString().get());
     PrintF("\n\nSubject string: '%s'\n\n", subject->ToCString().get());
   }
 #endif
+
+  // Prepare space for the return values.
   int required_registers = RegExp::IrregexpPrepare(isolate, regexp, subject);
   if (required_registers < 0) {
     // Compiling failed with an exception.
@@ -830,6 +833,26 @@ bool RegExpImpl::Compile(Isolate* isolate, Zone* zone, RegExpCompileData* data,
   RegExpCompiler::CompilationResult result = compiler.Assemble(
       isolate, macro_assembler.get(), node, data->capture_count, pattern);
 
+  // Code / bytecode printing.
+  {
+#ifdef ENABLE_DISASSEMBLER
+    if (FLAG_print_regexp_code &&
+        data->compilation_target == RegExpCompilationTarget::kNative) {
+      CodeTracer::Scope trace_scope(isolate->GetCodeTracer());
+      OFStream os(trace_scope.file());
+      Handle<Code> c(Code::cast(result.code), isolate);
+      auto pattern_cstring = pattern->ToCString();
+      c->Disassemble(pattern_cstring.get(), os);
+    }
+#endif
+    if (FLAG_print_regexp_bytecode &&
+        data->compilation_target == RegExpCompilationTarget::kBytecode) {
+      Handle<ByteArray> bytecode(ByteArray::cast(result.code), isolate);
+      auto pattern_cstring = pattern->ToCString();
+      IrregexpInterpreter::Disassemble(*bytecode, pattern_cstring.get());
+    }
+  }
+
   if (FLAG_correctness_fuzzer_suppressions &&
       strncmp(result.error_message, "Stack overflow", 15) == 0) {
     FATAL("Aborting on stack overflow");