SPIRV-Tools/source/text_handler.cpp
Alastair Donaldson 388ce0ee64
spirv-as: Avoid recursion when skipping whitespace (#4866)
Excessive whitespace can lead to stack overflow during parsing as each
character of skipped whitespace involves a recursive call. An
iterative solution avoids this.

Fixes #4729.
2022-07-26 10:56:04 -04:00

395 lines
13 KiB
C++

// Copyright (c) 2015-2016 The Khronos Group Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "source/text_handler.h"
#include <algorithm>
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <tuple>
#include "source/assembly_grammar.h"
#include "source/binary.h"
#include "source/ext_inst.h"
#include "source/instruction.h"
#include "source/opcode.h"
#include "source/text.h"
#include "source/util/bitutils.h"
#include "source/util/hex_float.h"
#include "source/util/parse_number.h"
#include "source/util/string_utils.h"
namespace spvtools {
namespace {
// Advances |text| to the start of the next line and writes the new position to
// |position|.
spv_result_t advanceLine(spv_text text, spv_position position) {
while (true) {
if (position->index >= text->length) return SPV_END_OF_STREAM;
switch (text->str[position->index]) {
case '\0':
return SPV_END_OF_STREAM;
case '\n':
position->column = 0;
position->line++;
position->index++;
return SPV_SUCCESS;
default:
position->column++;
position->index++;
break;
}
}
}
// Advances |text| to first non white space character and writes the new
// position to |position|.
// If a null terminator is found during the text advance, SPV_END_OF_STREAM is
// returned, SPV_SUCCESS otherwise. No error checking is performed on the
// parameters, its the users responsibility to ensure these are non null.
spv_result_t advance(spv_text text, spv_position position) {
// NOTE: Consume white space, otherwise don't advance.
while (true) {
if (position->index >= text->length) return SPV_END_OF_STREAM;
switch (text->str[position->index]) {
case '\0':
return SPV_END_OF_STREAM;
case ';':
if (spv_result_t error = advanceLine(text, position)) return error;
continue;
case ' ':
case '\t':
case '\r':
position->column++;
position->index++;
continue;
case '\n':
position->column = 0;
position->line++;
position->index++;
continue;
default:
return SPV_SUCCESS;
}
}
}
// Fetches the next word from the given text stream starting from the given
// *position. On success, writes the decoded word into *word and updates
// *position to the location past the returned word.
//
// A word ends at the next comment or whitespace. However, double-quoted
// strings remain intact, and a backslash always escapes the next character.
spv_result_t getWord(spv_text text, spv_position position, std::string* word) {
if (!text->str || !text->length) return SPV_ERROR_INVALID_TEXT;
if (!position) return SPV_ERROR_INVALID_POINTER;
const size_t start_index = position->index;
bool quoting = false;
bool escaping = false;
// NOTE: Assumes first character is not white space!
while (true) {
if (position->index >= text->length) {
word->assign(text->str + start_index, text->str + position->index);
return SPV_SUCCESS;
}
const char ch = text->str[position->index];
if (ch == '\\') {
escaping = !escaping;
} else {
switch (ch) {
case '"':
if (!escaping) quoting = !quoting;
break;
case ' ':
case ';':
case '\t':
case '\n':
case '\r':
if (escaping || quoting) break;
word->assign(text->str + start_index, text->str + position->index);
return SPV_SUCCESS;
case '\0': { // NOTE: End of word found!
word->assign(text->str + start_index, text->str + position->index);
return SPV_SUCCESS;
}
default:
break;
}
escaping = false;
}
position->column++;
position->index++;
}
}
// Returns true if the characters in the text as position represent
// the start of an Opcode.
bool startsWithOp(spv_text text, spv_position position) {
if (text->length < position->index + 3) return false;
char ch0 = text->str[position->index];
char ch1 = text->str[position->index + 1];
char ch2 = text->str[position->index + 2];
return ('O' == ch0 && 'p' == ch1 && ('A' <= ch2 && ch2 <= 'Z'));
}
} // namespace
const IdType kUnknownType = {0, false, IdTypeClass::kBottom};
// TODO(dneto): Reorder AssemblyContext definitions to match declaration order.
// This represents all of the data that is only valid for the duration of
// a single compilation.
uint32_t AssemblyContext::spvNamedIdAssignOrGet(const char* textValue) {
if (!ids_to_preserve_.empty()) {
uint32_t id = 0;
if (spvtools::utils::ParseNumber(textValue, &id)) {
if (ids_to_preserve_.find(id) != ids_to_preserve_.end()) {
bound_ = std::max(bound_, id + 1);
return id;
}
}
}
const auto it = named_ids_.find(textValue);
if (it == named_ids_.end()) {
uint32_t id = next_id_++;
if (!ids_to_preserve_.empty()) {
while (ids_to_preserve_.find(id) != ids_to_preserve_.end()) {
id = next_id_++;
}
}
named_ids_.emplace(textValue, id);
bound_ = std::max(bound_, id + 1);
return id;
}
return it->second;
}
uint32_t AssemblyContext::getBound() const { return bound_; }
spv_result_t AssemblyContext::advance() {
return spvtools::advance(text_, &current_position_);
}
spv_result_t AssemblyContext::getWord(std::string* word,
spv_position next_position) {
*next_position = current_position_;
return spvtools::getWord(text_, next_position, word);
}
bool AssemblyContext::startsWithOp() {
return spvtools::startsWithOp(text_, &current_position_);
}
bool AssemblyContext::isStartOfNewInst() {
spv_position_t pos = current_position_;
if (spvtools::advance(text_, &pos)) return false;
if (spvtools::startsWithOp(text_, &pos)) return true;
std::string word;
pos = current_position_;
if (spvtools::getWord(text_, &pos, &word)) return false;
if ('%' != word.front()) return false;
if (spvtools::advance(text_, &pos)) return false;
if (spvtools::getWord(text_, &pos, &word)) return false;
if ("=" != word) return false;
if (spvtools::advance(text_, &pos)) return false;
if (spvtools::startsWithOp(text_, &pos)) return true;
return false;
}
char AssemblyContext::peek() const {
return text_->str[current_position_.index];
}
bool AssemblyContext::hasText() const {
return text_->length > current_position_.index;
}
void AssemblyContext::seekForward(uint32_t size) {
current_position_.index += size;
current_position_.column += size;
}
spv_result_t AssemblyContext::binaryEncodeU32(const uint32_t value,
spv_instruction_t* pInst) {
pInst->words.insert(pInst->words.end(), value);
return SPV_SUCCESS;
}
spv_result_t AssemblyContext::binaryEncodeNumericLiteral(
const char* val, spv_result_t error_code, const IdType& type,
spv_instruction_t* pInst) {
using spvtools::utils::EncodeNumberStatus;
// Populate the NumberType from the IdType for parsing.
spvtools::utils::NumberType number_type;
switch (type.type_class) {
case IdTypeClass::kOtherType:
return diagnostic(SPV_ERROR_INTERNAL)
<< "Unexpected numeric literal type";
case IdTypeClass::kScalarIntegerType:
if (type.isSigned) {
number_type = {type.bitwidth, SPV_NUMBER_SIGNED_INT};
} else {
number_type = {type.bitwidth, SPV_NUMBER_UNSIGNED_INT};
}
break;
case IdTypeClass::kScalarFloatType:
number_type = {type.bitwidth, SPV_NUMBER_FLOATING};
break;
case IdTypeClass::kBottom:
// kBottom means the type is unknown and we need to infer the type before
// parsing the number. The rule is: If there is a decimal point, treat
// the value as a floating point value, otherwise a integer value, then
// if the first char of the integer text is '-', treat the integer as a
// signed integer, otherwise an unsigned integer.
uint32_t bitwidth = static_cast<uint32_t>(assumedBitWidth(type));
if (strchr(val, '.')) {
number_type = {bitwidth, SPV_NUMBER_FLOATING};
} else if (type.isSigned || val[0] == '-') {
number_type = {bitwidth, SPV_NUMBER_SIGNED_INT};
} else {
number_type = {bitwidth, SPV_NUMBER_UNSIGNED_INT};
}
break;
}
std::string error_msg;
EncodeNumberStatus parse_status = ParseAndEncodeNumber(
val, number_type,
[this, pInst](uint32_t d) { this->binaryEncodeU32(d, pInst); },
&error_msg);
switch (parse_status) {
case EncodeNumberStatus::kSuccess:
return SPV_SUCCESS;
case EncodeNumberStatus::kInvalidText:
return diagnostic(error_code) << error_msg;
case EncodeNumberStatus::kUnsupported:
return diagnostic(SPV_ERROR_INTERNAL) << error_msg;
case EncodeNumberStatus::kInvalidUsage:
return diagnostic(SPV_ERROR_INVALID_TEXT) << error_msg;
}
// This line is not reachable, only added to satisfy the compiler.
return diagnostic(SPV_ERROR_INTERNAL)
<< "Unexpected result code from ParseAndEncodeNumber()";
}
spv_result_t AssemblyContext::binaryEncodeString(const char* value,
spv_instruction_t* pInst) {
const size_t length = strlen(value);
const size_t wordCount = (length / 4) + 1;
const size_t oldWordCount = pInst->words.size();
const size_t newWordCount = oldWordCount + wordCount;
// TODO(dneto): We can just defer this check until later.
if (newWordCount > SPV_LIMIT_INSTRUCTION_WORD_COUNT_MAX) {
return diagnostic() << "Instruction too long: more than "
<< SPV_LIMIT_INSTRUCTION_WORD_COUNT_MAX << " words.";
}
pInst->words.reserve(newWordCount);
spvtools::utils::AppendToVector(value, &pInst->words);
return SPV_SUCCESS;
}
spv_result_t AssemblyContext::recordTypeDefinition(
const spv_instruction_t* pInst) {
uint32_t value = pInst->words[1];
if (types_.find(value) != types_.end()) {
return diagnostic() << "Value " << value
<< " has already been used to generate a type";
}
if (pInst->opcode == SpvOpTypeInt) {
if (pInst->words.size() != 4)
return diagnostic() << "Invalid OpTypeInt instruction";
types_[value] = {pInst->words[2], pInst->words[3] != 0,
IdTypeClass::kScalarIntegerType};
} else if (pInst->opcode == SpvOpTypeFloat) {
if (pInst->words.size() != 3)
return diagnostic() << "Invalid OpTypeFloat instruction";
types_[value] = {pInst->words[2], false, IdTypeClass::kScalarFloatType};
} else {
types_[value] = {0, false, IdTypeClass::kOtherType};
}
return SPV_SUCCESS;
}
IdType AssemblyContext::getTypeOfTypeGeneratingValue(uint32_t value) const {
auto type = types_.find(value);
if (type == types_.end()) {
return kUnknownType;
}
return std::get<1>(*type);
}
IdType AssemblyContext::getTypeOfValueInstruction(uint32_t value) const {
auto type_value = value_types_.find(value);
if (type_value == value_types_.end()) {
return {0, false, IdTypeClass::kBottom};
}
return getTypeOfTypeGeneratingValue(std::get<1>(*type_value));
}
spv_result_t AssemblyContext::recordTypeIdForValue(uint32_t value,
uint32_t type) {
bool successfully_inserted = false;
std::tie(std::ignore, successfully_inserted) =
value_types_.insert(std::make_pair(value, type));
if (!successfully_inserted)
return diagnostic() << "Value is being defined a second time";
return SPV_SUCCESS;
}
spv_result_t AssemblyContext::recordIdAsExtInstImport(
uint32_t id, spv_ext_inst_type_t type) {
bool successfully_inserted = false;
std::tie(std::ignore, successfully_inserted) =
import_id_to_ext_inst_type_.insert(std::make_pair(id, type));
if (!successfully_inserted)
return diagnostic() << "Import Id is being defined a second time";
return SPV_SUCCESS;
}
spv_ext_inst_type_t AssemblyContext::getExtInstTypeForId(uint32_t id) const {
auto type = import_id_to_ext_inst_type_.find(id);
if (type == import_id_to_ext_inst_type_.end()) {
return SPV_EXT_INST_TYPE_NONE;
}
return std::get<1>(*type);
}
std::set<uint32_t> AssemblyContext::GetNumericIds() const {
std::set<uint32_t> ids;
for (const auto& kv : named_ids_) {
uint32_t id;
if (spvtools::utils::ParseNumber(kv.first.c_str(), &id)) ids.insert(id);
}
return ids;
}
} // namespace spvtools