blob: c961051c092c55bd13632a4c9dcca4af6d5fb6a8 [file] [log] [blame]
/*
* Copyright (C) 2015 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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 "config.h"
#include "DFABytecodeCompiler.h"
#if ENABLE(CONTENT_EXTENSIONS)
#include "ContentExtensionRule.h"
#include "DFA.h"
#include "DFANode.h"
namespace WebCore {
namespace ContentExtensions {
template <typename IntType>
inline void append(Vector<DFABytecode>& bytecode, IntType value)
{
bytecode.grow(bytecode.size() + sizeof(IntType));
*reinterpret_cast<IntType*>(&bytecode[bytecode.size() - sizeof(IntType)]) = value;
}
inline void appendZeroes(Vector<DFABytecode>& bytecode, DFABytecodeJumpSize jumpSize)
{
switch (jumpSize) {
case DFABytecodeJumpSize::Int8:
append<int8_t>(bytecode, 0); // This value will be set when linking.
break;
case DFABytecodeJumpSize::Int16:
append<int16_t>(bytecode, 0); // This value will be set when linking.
break;
case DFABytecodeJumpSize::Int24:
append<uint16_t>(bytecode, 0);
append<int8_t>(bytecode, 0); // These values will be set when linking.
break;
case DFABytecodeJumpSize::Int32:
append<int32_t>(bytecode, 0); // This value will be set when linking.
break;
}
}
template <typename IntType>
inline void setBits(Vector<DFABytecode>& bytecode, uint32_t index, IntType value)
{
RELEASE_ASSERT(index + sizeof(IntType) <= bytecode.size());
ASSERT_WITH_MESSAGE(!*reinterpret_cast<IntType*>(&bytecode[index]), "Right now we should only be using setBits to overwrite values that were zero as a placeholder.");
*reinterpret_cast<IntType*>(&bytecode[index]) = value;
}
static unsigned appendActionBytecodeSize(uint64_t action)
{
if (action & ActionFlagMask)
return sizeof(DFABytecodeInstruction) + sizeof(uint16_t) + sizeof(uint32_t);
return sizeof(DFABytecodeInstruction) + sizeof(uint32_t);
}
void DFABytecodeCompiler::emitAppendAction(uint64_t action)
{
// High bits are used to store flags. See compileRuleList.
if (action & ActionFlagMask) {
if (action & IfConditionFlag)
append<DFABytecodeInstruction>(m_bytecode, DFABytecodeInstruction::TestFlagsAndAppendActionWithIfCondition);
else
append<DFABytecodeInstruction>(m_bytecode, DFABytecodeInstruction::TestFlagsAndAppendAction);
append<uint16_t>(m_bytecode, static_cast<uint16_t>(action >> 32));
append<uint32_t>(m_bytecode, static_cast<uint32_t>(action));
} else {
if (action & IfConditionFlag)
append<DFABytecodeInstruction>(m_bytecode, DFABytecodeInstruction::AppendActionWithIfCondition);
else
append<DFABytecodeInstruction>(m_bytecode, DFABytecodeInstruction::AppendAction);
append<uint32_t>(m_bytecode, static_cast<uint32_t>(action));
}
}
int32_t DFABytecodeCompiler::longestPossibleJump(uint32_t instructionLocation, uint32_t sourceNodeIndex, uint32_t destinationNodeIndex)
{
if (m_nodeStartOffsets[destinationNodeIndex] == std::numeric_limits<uint32_t>::max()) {
// Jumping to a node that hasn't been compiled yet, we don't know exactly how far forward we will need to jump,
// so make sure we have enough room for the worst possible case, the farthest possible jump
// which would be the distance if there were no compacted branches between this jump and its destination.
ASSERT(instructionLocation >= m_nodeStartOffsets[sourceNodeIndex]);
ASSERT(m_maxNodeStartOffsets[destinationNodeIndex] > m_maxNodeStartOffsets[sourceNodeIndex]);
ASSERT(m_nodeStartOffsets[sourceNodeIndex] != std::numeric_limits<uint32_t>::max());
return m_maxNodeStartOffsets[destinationNodeIndex] - m_maxNodeStartOffsets[sourceNodeIndex] - (m_nodeStartOffsets[sourceNodeIndex] - instructionLocation);
}
// Jumping to an already compiled node, we already know exactly where we will need to jump to.
ASSERT(m_nodeStartOffsets[destinationNodeIndex] <= instructionLocation);
return m_nodeStartOffsets[destinationNodeIndex] - instructionLocation;
}
void DFABytecodeCompiler::emitJump(uint32_t sourceNodeIndex, uint32_t destinationNodeIndex)
{
uint32_t instructionLocation = m_bytecode.size();
uint32_t jumpLocation = instructionLocation + sizeof(uint8_t);
int32_t longestPossibleJumpDistance = longestPossibleJump(instructionLocation, sourceNodeIndex, destinationNodeIndex);
DFABytecodeJumpSize jumpSize = smallestPossibleJumpSize(longestPossibleJumpDistance);
append<uint8_t>(m_bytecode, static_cast<uint8_t>(DFABytecodeInstruction::Jump) | jumpSize);
m_linkRecords.append(LinkRecord({jumpSize, longestPossibleJumpDistance, instructionLocation, jumpLocation, destinationNodeIndex}));
appendZeroes(m_bytecode, jumpSize);
}
void DFABytecodeCompiler::emitCheckValue(uint8_t value, uint32_t sourceNodeIndex, uint32_t destinationNodeIndex, bool caseSensitive)
{
uint32_t instructionLocation = m_bytecode.size();
uint32_t jumpLocation = instructionLocation + 2 * sizeof(uint8_t);
int32_t longestPossibleJumpDistance = longestPossibleJump(instructionLocation, sourceNodeIndex, destinationNodeIndex);
DFABytecodeJumpSize jumpSize = smallestPossibleJumpSize(longestPossibleJumpDistance);
DFABytecodeInstruction instruction = caseSensitive ? DFABytecodeInstruction::CheckValueCaseSensitive : DFABytecodeInstruction::CheckValueCaseInsensitive;
append<uint8_t>(m_bytecode, static_cast<uint8_t>(instruction) | jumpSize);
append<uint8_t>(m_bytecode, value);
m_linkRecords.append(LinkRecord({jumpSize, longestPossibleJumpDistance, instructionLocation, jumpLocation, destinationNodeIndex}));
appendZeroes(m_bytecode, jumpSize);
}
void DFABytecodeCompiler::emitCheckValueRange(uint8_t lowValue, uint8_t highValue, uint32_t sourceNodeIndex, uint32_t destinationNodeIndex, bool caseSensitive)
{
ASSERT_WITH_MESSAGE(lowValue < highValue, "The instruction semantic impose lowValue is strictly less than highValue.");
uint32_t instructionLocation = m_bytecode.size();
uint32_t jumpLocation = instructionLocation + 3 * sizeof(uint8_t);
int32_t longestPossibleJumpDistance = longestPossibleJump(instructionLocation, sourceNodeIndex, destinationNodeIndex);
DFABytecodeJumpSize jumpSize = smallestPossibleJumpSize(longestPossibleJumpDistance);
DFABytecodeInstruction instruction = caseSensitive ? DFABytecodeInstruction::CheckValueRangeCaseSensitive : DFABytecodeInstruction::CheckValueRangeCaseInsensitive;
append<uint8_t>(m_bytecode, static_cast<uint8_t>(instruction) | jumpSize);
append<uint8_t>(m_bytecode, lowValue);
append<uint8_t>(m_bytecode, highValue);
m_linkRecords.append(LinkRecord({jumpSize, longestPossibleJumpDistance, instructionLocation, jumpLocation, destinationNodeIndex}));
appendZeroes(m_bytecode, jumpSize);
}
void DFABytecodeCompiler::emitTerminate()
{
append<DFABytecodeInstruction>(m_bytecode, DFABytecodeInstruction::Terminate);
}
void DFABytecodeCompiler::compileNode(uint32_t index, bool root)
{
unsigned startSize = m_bytecode.size();
const DFANode& node = m_dfa.nodes[index];
if (node.isKilled()) {
ASSERT(m_nodeStartOffsets[index] == std::numeric_limits<uint32_t>::max());
return;
}
// Record starting index for linking.
if (!root)
m_nodeStartOffsets[index] = m_bytecode.size();
for (uint64_t action : node.actions(m_dfa))
emitAppendAction(action);
// If we jump to the root, we don't want to re-add its actions to a HashSet.
// We know we have already added them because the root is always compiled first and we always start interpreting at the beginning.
if (root)
m_nodeStartOffsets[index] = m_bytecode.size();
compileNodeTransitions(index);
ASSERT_UNUSED(startSize, m_bytecode.size() - startSize <= compiledNodeMaxBytecodeSize(index));
}
unsigned DFABytecodeCompiler::compiledNodeMaxBytecodeSize(uint32_t index)
{
const DFANode& node = m_dfa.nodes[index];
if (node.isKilled())
return 0;
unsigned size = 0;
for (uint64_t action : node.actions(m_dfa))
size += appendActionBytecodeSize(action);
size += nodeTransitionsMaxBytecodeSize(node);
return size;
}
DFABytecodeCompiler::JumpTable DFABytecodeCompiler::extractJumpTable(Vector<DFABytecodeCompiler::Range>& ranges, unsigned firstRange, unsigned lastRange)
{
ASSERT(lastRange > firstRange);
ASSERT(lastRange < ranges.size());
JumpTable jumpTable;
jumpTable.min = ranges[firstRange].min;
jumpTable.max = ranges[lastRange].max;
jumpTable.caseSensitive = ranges[lastRange].caseSensitive;
unsigned size = lastRange - firstRange + 1;
jumpTable.destinations.reserveInitialCapacity(size);
for (unsigned i = firstRange; i <= lastRange; ++i) {
const Range& range = ranges[i];
ASSERT(range.caseSensitive == jumpTable.caseSensitive);
ASSERT(range.min == range.max);
ASSERT(range.min >= jumpTable.min);
ASSERT(range.min <= jumpTable.max);
jumpTable.destinations.uncheckedAppend(range.destination);
}
ranges.remove(firstRange, size);
return jumpTable;
}
DFABytecodeCompiler::Transitions DFABytecodeCompiler::transitions(const DFANode& node)
{
Transitions transitions;
uint32_t destinations[128];
memset(destinations, 0xff, sizeof(destinations));
const uint32_t noDestination = std::numeric_limits<uint32_t>::max();
transitions.useFallbackTransition = node.canUseFallbackTransition(m_dfa);
if (transitions.useFallbackTransition)
transitions.fallbackTransitionTarget = node.bestFallbackTarget(m_dfa);
for (const auto& transition : node.transitions(m_dfa)) {
uint32_t targetNodeIndex = transition.target();
if (transitions.useFallbackTransition && transitions.fallbackTransitionTarget == targetNodeIndex)
continue;
for (uint16_t i = transition.range().first; i <= transition.range().last; ++i)
destinations[i] = targetNodeIndex;
}
Vector<Range>& ranges = transitions.ranges;
uint8_t rangeMin;
bool hasRangeMin = false;
for (uint8_t i = 0; i < 128; i++) {
if (hasRangeMin) {
if (destinations[i] != destinations[rangeMin]) {
// This is the end of a range. Check if it can be case insensitive.
uint8_t rangeMax = i - 1;
bool caseSensitive = true;
if (rangeMin >= 'A' && rangeMax <= 'Z') {
caseSensitive = false;
for (uint8_t rangeIndex = rangeMin; rangeIndex <= rangeMax; rangeIndex++) {
if (destinations[rangeMin] != destinations[toASCIILower(rangeIndex)]) {
caseSensitive = true;
break;
}
}
}
if (!caseSensitive) {
// If all the lower-case destinations are the same as the upper-case destinations,
// then they will be covered by a case-insensitive range and will not need their own range.
for (uint8_t rangeIndex = rangeMin; rangeIndex <= rangeMax; rangeIndex++) {
ASSERT(destinations[rangeMin] == destinations[toASCIILower(rangeIndex)]);
destinations[toASCIILower(rangeIndex)] = noDestination;
}
ranges.append(Range(toASCIILower(rangeMin), toASCIILower(rangeMax), destinations[rangeMin], caseSensitive));
} else
ranges.append(Range(rangeMin, rangeMax, destinations[rangeMin], caseSensitive));
if (destinations[i] == noDestination)
hasRangeMin = false;
else
rangeMin = i;
}
} else {
if (destinations[i] != noDestination) {
rangeMin = i;
hasRangeMin = true;
}
}
}
if (hasRangeMin) {
// Ranges are appended after passing the end of them.
// If a range goes to 127, we will have an uncommitted rangeMin because the loop does not check 128.
// If a range goes to 127, there will never be values higher than it, so checking for case-insensitive ranges would always fail.
ranges.append(Range(rangeMin, 127, destinations[rangeMin], true));
}
Vector<JumpTable>& jumpTables = transitions.jumpTables;
unsigned rangePosition = 0;
unsigned baseRangePosition = std::numeric_limits<unsigned>::max();
Range* baseRange = nullptr;
while (rangePosition < ranges.size()) {
auto& range = ranges[rangePosition];
if (baseRange) {
if (range.min != range.max
|| baseRange->caseSensitive != range.caseSensitive
|| ranges[rangePosition - 1].max + 1 != range.min) {
if (rangePosition - baseRangePosition > 1) {
jumpTables.append(extractJumpTable(ranges, baseRangePosition, rangePosition - 1));
rangePosition = baseRangePosition;
}
baseRangePosition = std::numeric_limits<unsigned>::max();
baseRange = nullptr;
}
} else {
if (range.min == range.max) {
baseRangePosition = rangePosition;
baseRange = &range;
}
}
++rangePosition;
}
if (baseRange && ranges.size() - baseRangePosition > 1)
jumpTables.append(extractJumpTable(ranges, baseRangePosition, ranges.size() - 1));
return transitions;
}
unsigned DFABytecodeCompiler::checkForJumpTableMaxBytecodeSize(const JumpTable& jumpTable)
{
unsigned baselineSize = sizeof(DFABytecodeInstruction::CheckValueRangeCaseInsensitive) + 2 * sizeof(uint8_t);
unsigned targetsSize = (jumpTable.max - jumpTable.min + 1) * sizeof(uint32_t);
return baselineSize + targetsSize;
}
unsigned DFABytecodeCompiler::checkForRangeMaxBytecodeSize(const Range& range)
{
if (range.min == range.max)
return sizeof(DFABytecodeInstruction::CheckValueCaseInsensitive) + sizeof(uint8_t) + sizeof(uint32_t);
return sizeof(DFABytecodeInstruction::CheckValueRangeCaseInsensitive) + 2 * sizeof(uint8_t) + sizeof(uint32_t);
}
void DFABytecodeCompiler::compileJumpTable(uint32_t nodeIndex, const JumpTable& jumpTable)
{
unsigned startSize = m_bytecode.size();
ASSERT_WITH_MESSAGE(jumpTable.max < 128, "The DFA engine only supports the ASCII alphabet.");
ASSERT(jumpTable.min <= jumpTable.max);
uint32_t instructionLocation = m_bytecode.size();
DFABytecodeJumpSize jumpSize = Int8;
for (uint32_t destinationNodeIndex : jumpTable.destinations) {
int32_t longestPossibleJumpDistance = longestPossibleJump(instructionLocation, nodeIndex, destinationNodeIndex);
DFABytecodeJumpSize localJumpSize = smallestPossibleJumpSize(longestPossibleJumpDistance);
jumpSize = std::max(jumpSize, localJumpSize);
}
DFABytecodeInstruction instruction = jumpTable.caseSensitive ? DFABytecodeInstruction::JumpTableCaseSensitive : DFABytecodeInstruction::JumpTableCaseInsensitive;
append<uint8_t>(m_bytecode, static_cast<uint8_t>(instruction) | jumpSize);
append<uint8_t>(m_bytecode, jumpTable.min);
append<uint8_t>(m_bytecode, jumpTable.max);
for (uint32_t destinationNodeIndex : jumpTable.destinations) {
int32_t longestPossibleJumpDistance = longestPossibleJump(instructionLocation, nodeIndex, destinationNodeIndex);
uint32_t jumpLocation = m_bytecode.size();
m_linkRecords.append(LinkRecord({jumpSize, longestPossibleJumpDistance, instructionLocation, jumpLocation, destinationNodeIndex}));
appendZeroes(m_bytecode, jumpSize);
}
ASSERT_UNUSED(startSize, m_bytecode.size() - startSize <= checkForJumpTableMaxBytecodeSize(jumpTable));
}
void DFABytecodeCompiler::compileCheckForRange(uint32_t nodeIndex, const Range& range)
{
unsigned startSize = m_bytecode.size();
ASSERT_WITH_MESSAGE(range.max < 128, "The DFA engine only supports the ASCII alphabet.");
ASSERT(range.min <= range.max);
if (range.min == range.max)
emitCheckValue(range.min, nodeIndex, range.destination, range.caseSensitive);
else
emitCheckValueRange(range.min, range.max, nodeIndex, range.destination, range.caseSensitive);
ASSERT_UNUSED(startSize, m_bytecode.size() - startSize <= checkForRangeMaxBytecodeSize(range));
}
unsigned DFABytecodeCompiler::nodeTransitionsMaxBytecodeSize(const DFANode& node)
{
unsigned size = 0;
Transitions nodeTransitions = transitions(node);
for (const auto& jumpTable : nodeTransitions.jumpTables)
size += checkForJumpTableMaxBytecodeSize(jumpTable);
for (const auto& range : nodeTransitions.ranges)
size += checkForRangeMaxBytecodeSize(range);
if (nodeTransitions.useFallbackTransition)
size += sizeof(DFABytecodeInstruction::Jump) + sizeof(uint32_t);
else
size += instructionSizeWithArguments(DFABytecodeInstruction::Terminate);
return size;
}
void DFABytecodeCompiler::compileNodeTransitions(uint32_t nodeIndex)
{
const DFANode& node = m_dfa.nodes[nodeIndex];
unsigned startSize = m_bytecode.size();
Transitions nodeTransitions = transitions(node);
for (const auto& jumpTable : nodeTransitions.jumpTables)
compileJumpTable(nodeIndex, jumpTable);
for (const auto& range : nodeTransitions.ranges)
compileCheckForRange(nodeIndex, range);
if (nodeTransitions.useFallbackTransition)
emitJump(nodeIndex, nodeTransitions.fallbackTransitionTarget);
else
emitTerminate();
ASSERT_UNUSED(startSize, m_bytecode.size() - startSize <= nodeTransitionsMaxBytecodeSize(node));
}
void DFABytecodeCompiler::compile()
{
uint32_t startLocation = m_bytecode.size();
append<DFAHeader>(m_bytecode, 0); // This will be set when we are finished compiling this DFA.
m_nodeStartOffsets.resize(m_dfa.nodes.size());
for (unsigned i = 0; i < m_dfa.nodes.size(); ++i)
m_nodeStartOffsets[i] = std::numeric_limits<uint32_t>::max();
// Populate m_maxNodeStartOffsets with a worst-case index of where the node would be with no branch compaction.
// Compacting the branches using 1-4 byte signed jump distances should only make nodes closer together than this.
ASSERT(m_maxNodeStartOffsets.isEmpty());
m_maxNodeStartOffsets.clear();
m_maxNodeStartOffsets.resize(m_dfa.nodes.size());
unsigned rootActionsSize = 0;
for (uint64_t action : m_dfa.nodes[m_dfa.root].actions(m_dfa))
rootActionsSize += appendActionBytecodeSize(action);
m_maxNodeStartOffsets[m_dfa.root] = sizeof(DFAHeader) + rootActionsSize;
unsigned nextIndex = sizeof(DFAHeader) + compiledNodeMaxBytecodeSize(m_dfa.root);
for (uint32_t i = 0; i < m_dfa.nodes.size(); i++) {
if (i != m_dfa.root) {
m_maxNodeStartOffsets[i] = nextIndex;
nextIndex += compiledNodeMaxBytecodeSize(i);
}
}
// Make sure the root is always at the beginning of the bytecode.
compileNode(m_dfa.root, true);
for (uint32_t i = 0; i < m_dfa.nodes.size(); i++) {
if (i != m_dfa.root)
compileNode(i, false);
}
ASSERT(m_maxNodeStartOffsets.size() == m_nodeStartOffsets.size());
for (unsigned i = 0; i < m_dfa.nodes.size(); ++i) {
if (m_nodeStartOffsets[i] != std::numeric_limits<uint32_t>::max())
ASSERT(m_maxNodeStartOffsets[i] >= m_nodeStartOffsets[i]);
}
// Link.
for (const auto& linkRecord : m_linkRecords) {
uint32_t destination = m_nodeStartOffsets[linkRecord.destinationNodeIndex];
RELEASE_ASSERT(destination < std::numeric_limits<int32_t>::max());
int32_t distance = destination - linkRecord.instructionLocation;
ASSERT(abs(distance) <= abs(linkRecord.longestPossibleJump));
switch (linkRecord.jumpSize) {
case Int8:
RELEASE_ASSERT(distance == static_cast<int8_t>(distance));
setBits<int8_t>(m_bytecode, linkRecord.jumpLocation, static_cast<int8_t>(distance));
break;
case Int16:
RELEASE_ASSERT(distance == static_cast<int16_t>(distance));
setBits<int16_t>(m_bytecode, linkRecord.jumpLocation, static_cast<int16_t>(distance));
break;
case Int24:
RELEASE_ASSERT(distance >= Int24Min && distance <= Int24Max);
setBits<uint16_t>(m_bytecode, linkRecord.jumpLocation, static_cast<uint16_t>(distance));
setBits<int8_t>(m_bytecode, linkRecord.jumpLocation + sizeof(int16_t), static_cast<int8_t>(distance >> 16));
break;
case Int32:
setBits<int32_t>(m_bytecode, linkRecord.jumpLocation, distance);
break;
}
}
setBits<DFAHeader>(m_bytecode, startLocation, m_bytecode.size() - startLocation);
}
} // namespace ContentExtensions
} // namespace WebCore
#endif // ENABLE(CONTENT_EXTENSIONS)