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cobalt / cobalt / e77c070364e97b7a7deea396227c08805cb9e66d / . / src / third_party / WebKit / Source / JavaScriptCore / yarr / YarrJIT.cpp
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/*
* Copyright (C) 2009 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. ``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
* 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 "YarrJIT.h"
#include <wtf/ASCIICType.h>
#include "LinkBuffer.h"
#include "Options.h"
#include "Yarr.h"
#include "YarrCanonicalizeUCS2.h"
#if ENABLE(YARR_JIT)
using namespace WTF;
namespace JSC { namespace Yarr {
template<YarrJITCompileMode compileMode>
class YarrGenerator : private MacroAssembler {
friend void jitCompile(JSGlobalData*, YarrCodeBlock& jitObject, const String& pattern, unsigned& numSubpatterns, const char*& error, bool ignoreCase, bool multiline);
#if CPU(ARM)
static const RegisterID input = ARMRegisters::r0;
static const RegisterID index = ARMRegisters::r1;
static const RegisterID length = ARMRegisters::r2;
static const RegisterID output = ARMRegisters::r4;
static const RegisterID regT0 = ARMRegisters::r5;
static const RegisterID regT1 = ARMRegisters::r6;
static const RegisterID returnRegister = ARMRegisters::r0;
static const RegisterID returnRegister2 = ARMRegisters::r1;
#elif CPU(MIPS)
static const RegisterID input = MIPSRegisters::a0;
static const RegisterID index = MIPSRegisters::a1;
static const RegisterID length = MIPSRegisters::a2;
static const RegisterID output = MIPSRegisters::a3;
static const RegisterID regT0 = MIPSRegisters::t4;
static const RegisterID regT1 = MIPSRegisters::t5;
static const RegisterID returnRegister = MIPSRegisters::v0;
static const RegisterID returnRegister2 = MIPSRegisters::v1;
#elif CPU(SH4)
static const RegisterID input = SH4Registers::r4;
static const RegisterID index = SH4Registers::r5;
static const RegisterID length = SH4Registers::r6;
static const RegisterID output = SH4Registers::r7;
static const RegisterID regT0 = SH4Registers::r0;
static const RegisterID regT1 = SH4Registers::r1;
static const RegisterID returnRegister = SH4Registers::r0;
static const RegisterID returnRegister2 = SH4Registers::r1;
#elif CPU(X86)
static const RegisterID input = X86Registers::eax;
static const RegisterID index = X86Registers::edx;
static const RegisterID length = X86Registers::ecx;
static const RegisterID output = X86Registers::edi;
static const RegisterID regT0 = X86Registers::ebx;
static const RegisterID regT1 = X86Registers::esi;
static const RegisterID returnRegister = X86Registers::eax;
static const RegisterID returnRegister2 = X86Registers::edx;
#elif CPU(X86_64)
static const RegisterID input = X86Registers::edi;
static const RegisterID index = X86Registers::esi;
static const RegisterID length = X86Registers::edx;
static const RegisterID output = X86Registers::ecx;
static const RegisterID regT0 = X86Registers::eax;
static const RegisterID regT1 = X86Registers::ebx;
static const RegisterID returnRegister = X86Registers::eax;
static const RegisterID returnRegister2 = X86Registers::edx;
#endif
void optimizeAlternative(PatternAlternative* alternative)
{
if (!alternative->m_terms.size())
return;
for (unsigned i = 0; i < alternative->m_terms.size() - 1; ++i) {
PatternTerm& term = alternative->m_terms[i];
PatternTerm& nextTerm = alternative->m_terms[i + 1];
if ((term.type == PatternTerm::TypeCharacterClass)
&& (term.quantityType == QuantifierFixedCount)
&& (nextTerm.type == PatternTerm::TypePatternCharacter)
&& (nextTerm.quantityType == QuantifierFixedCount)) {
PatternTerm termCopy = term;
alternative->m_terms[i] = nextTerm;
alternative->m_terms[i + 1] = termCopy;
}
}
}
void matchCharacterClassRange(RegisterID character, JumpList& failures, JumpList& matchDest, const CharacterRange* ranges, unsigned count, unsigned* matchIndex, const UChar* matches, unsigned matchCount)
{
do {
// pick which range we're going to generate
int which = count >> 1;
char lo = ranges[which].begin;
char hi = ranges[which].end;
// check if there are any ranges or matches below lo. If not, just jl to failure -
// if there is anything else to check, check that first, if it falls through jmp to failure.
if ((*matchIndex < matchCount) && (matches[*matchIndex] < lo)) {
Jump loOrAbove = branch32(GreaterThanOrEqual, character, Imm32((unsigned short)lo));
// generate code for all ranges before this one
if (which)
matchCharacterClassRange(character, failures, matchDest, ranges, which, matchIndex, matches, matchCount);
while ((*matchIndex < matchCount) && (matches[*matchIndex] < lo)) {
matchDest.append(branch32(Equal, character, Imm32((unsigned short)matches[*matchIndex])));
++*matchIndex;
}
failures.append(jump());
loOrAbove.link(this);
} else if (which) {
Jump loOrAbove = branch32(GreaterThanOrEqual, character, Imm32((unsigned short)lo));
matchCharacterClassRange(character, failures, matchDest, ranges, which, matchIndex, matches, matchCount);
failures.append(jump());
loOrAbove.link(this);
} else
failures.append(branch32(LessThan, character, Imm32((unsigned short)lo)));
while ((*matchIndex < matchCount) && (matches[*matchIndex] <= hi))
++*matchIndex;
matchDest.append(branch32(LessThanOrEqual, character, Imm32((unsigned short)hi)));
// fall through to here, the value is above hi.
// shuffle along & loop around if there are any more matches to handle.
unsigned next = which + 1;
ranges += next;
count -= next;
} while (count);
}
void matchCharacterClass(RegisterID character, JumpList& matchDest, const CharacterClass* charClass)
{
if (charClass->m_table) {
ExtendedAddress tableEntry(character, reinterpret_cast<intptr_t>(charClass->m_table->m_table));
matchDest.append(branchTest8(charClass->m_table->m_inverted ? Zero : NonZero, tableEntry));
return;
}
Jump unicodeFail;
if (charClass->m_matchesUnicode.size() || charClass->m_rangesUnicode.size()) {
Jump isAscii = branch32(LessThanOrEqual, character, TrustedImm32(0x7f));
if (charClass->m_matchesUnicode.size()) {
for (unsigned i = 0; i < charClass->m_matchesUnicode.size(); ++i) {
UChar ch = charClass->m_matchesUnicode[i];
matchDest.append(branch32(Equal, character, Imm32(ch)));
}
}
if (charClass->m_rangesUnicode.size()) {
for (unsigned i = 0; i < charClass->m_rangesUnicode.size(); ++i) {
UChar lo = charClass->m_rangesUnicode[i].begin;
UChar hi = charClass->m_rangesUnicode[i].end;
Jump below = branch32(LessThan, character, Imm32(lo));
matchDest.append(branch32(LessThanOrEqual, character, Imm32(hi)));
below.link(this);
}
}
unicodeFail = jump();
isAscii.link(this);
}
if (charClass->m_ranges.size()) {
unsigned matchIndex = 0;
JumpList failures;
matchCharacterClassRange(character, failures, matchDest, charClass->m_ranges.begin(), charClass->m_ranges.size(), &matchIndex, charClass->m_matches.begin(), charClass->m_matches.size());
while (matchIndex < charClass->m_matches.size())
matchDest.append(branch32(Equal, character, Imm32((unsigned short)charClass->m_matches[matchIndex++])));
failures.link(this);
} else if (charClass->m_matches.size()) {
// optimization: gather 'a','A' etc back together, can mask & test once.
Vector<char> matchesAZaz;
for (unsigned i = 0; i < charClass->m_matches.size(); ++i) {
char ch = charClass->m_matches[i];
if (m_pattern.m_ignoreCase) {
if (isASCIILower(ch)) {
matchesAZaz.append(ch);
continue;
}
if (isASCIIUpper(ch))
continue;
}
matchDest.append(branch32(Equal, character, Imm32((unsigned short)ch)));
}
if (unsigned countAZaz = matchesAZaz.size()) {
or32(TrustedImm32(32), character);
for (unsigned i = 0; i < countAZaz; ++i)
matchDest.append(branch32(Equal, character, TrustedImm32(matchesAZaz[i])));
}
}
if (charClass->m_matchesUnicode.size() || charClass->m_rangesUnicode.size())
unicodeFail.link(this);
}
// Jumps if input not available; will have (incorrectly) incremented already!
Jump jumpIfNoAvailableInput(unsigned countToCheck = 0)
{
if (countToCheck)
add32(Imm32(countToCheck), index);
return branch32(Above, index, length);
}
Jump jumpIfAvailableInput(unsigned countToCheck)
{
add32(Imm32(countToCheck), index);
return branch32(BelowOrEqual, index, length);
}
Jump checkInput()
{
return branch32(BelowOrEqual, index, length);
}
Jump atEndOfInput()
{
return branch32(Equal, index, length);
}
Jump notAtEndOfInput()
{
return branch32(NotEqual, index, length);
}
Jump jumpIfCharNotEquals(UChar ch, int inputPosition, RegisterID character)
{
readCharacter(inputPosition, character);
// For case-insesitive compares, non-ascii characters that have different
// upper & lower case representations are converted to a character class.
ASSERT(!m_pattern.m_ignoreCase || isASCIIAlpha(ch) || isCanonicallyUnique(ch));
if (m_pattern.m_ignoreCase && isASCIIAlpha(ch)) {
or32(TrustedImm32(0x20), character);
ch |= 0x20;
}
return branch32(NotEqual, character, Imm32(ch));
}
void readCharacter(int inputPosition, RegisterID reg)
{
if (m_charSize == Char8)
load8(BaseIndex(input, index, TimesOne, inputPosition * sizeof(char)), reg);
else
load16(BaseIndex(input, index, TimesTwo, inputPosition * sizeof(UChar)), reg);
}
void storeToFrame(RegisterID reg, unsigned frameLocation)
{
poke(reg, frameLocation);
}
void storeToFrame(TrustedImm32 imm, unsigned frameLocation)
{
poke(imm, frameLocation);
}
DataLabelPtr storeToFrameWithPatch(unsigned frameLocation)
{
return storePtrWithPatch(TrustedImmPtr(0), Address(stackPointerRegister, frameLocation * sizeof(void*)));
}
void loadFromFrame(unsigned frameLocation, RegisterID reg)
{
peek(reg, frameLocation);
}
void loadFromFrameAndJump(unsigned frameLocation)
{
jump(Address(stackPointerRegister, frameLocation * sizeof(void*)));
}
void initCallFrame()
{
unsigned callFrameSize = m_pattern.m_body->m_callFrameSize;
if (callFrameSize)
subPtr(Imm32(callFrameSize * sizeof(void*)), stackPointerRegister);
}
void removeCallFrame()
{
unsigned callFrameSize = m_pattern.m_body->m_callFrameSize;
if (callFrameSize)
addPtr(Imm32(callFrameSize * sizeof(void*)), stackPointerRegister);
}
// Used to record subpatters, should only be called if compileMode is IncludeSubpatterns.
void setSubpatternStart(RegisterID reg, unsigned subpattern)
{
ASSERT(subpattern);
// FIXME: should be able to ASSERT(compileMode == IncludeSubpatterns), but then this function is conditionally NORETURN. :-(
store32(reg, Address(output, (subpattern << 1) * sizeof(int)));
}
void setSubpatternEnd(RegisterID reg, unsigned subpattern)
{
ASSERT(subpattern);
// FIXME: should be able to ASSERT(compileMode == IncludeSubpatterns), but then this function is conditionally NORETURN. :-(
store32(reg, Address(output, ((subpattern << 1) + 1) * sizeof(int)));
}
void clearSubpatternStart(unsigned subpattern)
{
ASSERT(subpattern);
// FIXME: should be able to ASSERT(compileMode == IncludeSubpatterns), but then this function is conditionally NORETURN. :-(
store32(TrustedImm32(-1), Address(output, (subpattern << 1) * sizeof(int)));
}
// We use one of three different strategies to track the start of the current match,
// while matching.
// 1) If the pattern has a fixed size, do nothing! - we calculate the value lazily
// at the end of matching. This is irrespective of compileMode, and in this case
// these methods should never be called.
// 2) If we're compiling IncludeSubpatterns, 'output' contains a pointer to an output
// vector, store the match start in the output vector.
// 3) If we're compiling MatchOnly, 'output' is unused, store the match start directly
// in this register.
void setMatchStart(RegisterID reg)
{
ASSERT(!m_pattern.m_body->m_hasFixedSize);
if (compileMode == IncludeSubpatterns)
store32(reg, output);
else
move(reg, output);
}
void getMatchStart(RegisterID reg)
{
ASSERT(!m_pattern.m_body->m_hasFixedSize);
if (compileMode == IncludeSubpatterns)
load32(output, reg);
else
move(output, reg);
}
enum YarrOpCode {
// These nodes wrap body alternatives - those in the main disjunction,
// rather than subpatterns or assertions. These are chained together in
// a doubly linked list, with a 'begin' node for the first alternative,
// a 'next' node for each subsequent alternative, and an 'end' node at
// the end. In the case of repeating alternatives, the 'end' node also
// has a reference back to 'begin'.
OpBodyAlternativeBegin,
OpBodyAlternativeNext,
OpBodyAlternativeEnd,
// Similar to the body alternatives, but used for subpatterns with two
// or more alternatives.
OpNestedAlternativeBegin,
OpNestedAlternativeNext,
OpNestedAlternativeEnd,
// Used for alternatives in subpatterns where there is only a single
// alternative (backtrackingis easier in these cases), or for alternatives
// which never need to be backtracked (those in parenthetical assertions,
// terminal subpatterns).
OpSimpleNestedAlternativeBegin,
OpSimpleNestedAlternativeNext,
OpSimpleNestedAlternativeEnd,
// Used to wrap 'Once' subpattern matches (quantityCount == 1).
OpParenthesesSubpatternOnceBegin,
OpParenthesesSubpatternOnceEnd,
// Used to wrap 'Terminal' subpattern matches (at the end of the regexp).
OpParenthesesSubpatternTerminalBegin,
OpParenthesesSubpatternTerminalEnd,
// Used to wrap parenthetical assertions.
OpParentheticalAssertionBegin,
OpParentheticalAssertionEnd,
// Wraps all simple terms (pattern characters, character classes).
OpTerm,
// Where an expression contains only 'once through' body alternatives
// and no repeating ones, this op is used to return match failure.
OpMatchFailed
};
// This structure is used to hold the compiled opcode information,
// including reference back to the original PatternTerm/PatternAlternatives,
// and JIT compilation data structures.
struct YarrOp {
explicit YarrOp(PatternTerm* term)
: m_op(OpTerm)
, m_term(term)
, m_isDeadCode(false)
{
}
explicit YarrOp(YarrOpCode op)
: m_op(op)
, m_isDeadCode(false)
{
}
// The operation, as a YarrOpCode, and also a reference to the PatternTerm.
YarrOpCode m_op;
PatternTerm* m_term;
// For alternatives, this holds the PatternAlternative and doubly linked
// references to this alternative's siblings. In the case of the
// OpBodyAlternativeEnd node at the end of a section of repeating nodes,
// m_nextOp will reference the OpBodyAlternativeBegin node of the first
// repeating alternative.
PatternAlternative* m_alternative;
size_t m_previousOp;
size_t m_nextOp;
// Used to record a set of Jumps out of the generated code, typically
// used for jumps out to backtracking code, and a single reentry back
// into the code for a node (likely where a backtrack will trigger
// rematching).
Label m_reentry;
JumpList m_jumps;
// Used for backtracking when the prior alternative did not consume any
// characters but matched.
Jump m_zeroLengthMatch;
// This flag is used to null out the second pattern character, when
// two are fused to match a pair together.
bool m_isDeadCode;
// Currently used in the case of some of the more complex management of
// 'm_checked', to cache the offset used in this alternative, to avoid
// recalculating it.
int m_checkAdjust;
// Used by OpNestedAlternativeNext/End to hold the pointer to the
// value that will be pushed into the pattern's frame to return to,
// upon backtracking back into the disjunction.
DataLabelPtr m_returnAddress;
};
// BacktrackingState
// This class encapsulates information about the state of code generation
// whilst generating the code for backtracking, when a term fails to match.
// Upon entry to code generation of the backtracking code for a given node,
// the Backtracking state will hold references to all control flow sources
// that are outputs in need of further backtracking from the prior node
// generated (which is the subsequent operation in the regular expression,
// and in the m_ops Vector, since we generated backtracking backwards).
// These references to control flow take the form of:
// - A jump list of jumps, to be linked to code that will backtrack them
// further.
// - A set of DataLabelPtr values, to be populated with values to be
// treated effectively as return addresses backtracking into complex
// subpatterns.
// - A flag indicating that the current sequence of generated code up to
// this point requires backtracking.
class BacktrackingState {
public:
BacktrackingState()
: m_pendingFallthrough(false)
{
}
// Add a jump or jumps, a return address, or set the flag indicating
// that the current 'fallthrough' control flow requires backtracking.
void append(const Jump& jump)
{
m_laterFailures.append(jump);
}
void append(JumpList& jumpList)
{
m_laterFailures.append(jumpList);
}
void append(const DataLabelPtr& returnAddress)
{
m_pendingReturns.append(returnAddress);
}
void fallthrough()
{
ASSERT(!m_pendingFallthrough);
m_pendingFallthrough = true;
}
// These methods clear the backtracking state, either linking to the
// current location, a provided label, or copying the backtracking out
// to a JumpList. All actions may require code generation to take place,
// and as such are passed a pointer to the assembler.
void link(MacroAssembler* assembler)
{
if (m_pendingReturns.size()) {
Label here(assembler);
for (unsigned i = 0; i < m_pendingReturns.size(); ++i)
m_backtrackRecords.append(ReturnAddressRecord(m_pendingReturns[i], here));
m_pendingReturns.clear();
}
m_laterFailures.link(assembler);
m_laterFailures.clear();
m_pendingFallthrough = false;
}
void linkTo(Label label, MacroAssembler* assembler)
{
if (m_pendingReturns.size()) {
for (unsigned i = 0; i < m_pendingReturns.size(); ++i)
m_backtrackRecords.append(ReturnAddressRecord(m_pendingReturns[i], label));
m_pendingReturns.clear();
}
if (m_pendingFallthrough)
assembler->jump(label);
m_laterFailures.linkTo(label, assembler);
m_laterFailures.clear();
m_pendingFallthrough = false;
}
void takeBacktracksToJumpList(JumpList& jumpList, MacroAssembler* assembler)
{
if (m_pendingReturns.size()) {
Label here(assembler);
for (unsigned i = 0; i < m_pendingReturns.size(); ++i)
m_backtrackRecords.append(ReturnAddressRecord(m_pendingReturns[i], here));
m_pendingReturns.clear();
m_pendingFallthrough = true;
}
if (m_pendingFallthrough)
jumpList.append(assembler->jump());
jumpList.append(m_laterFailures);
m_laterFailures.clear();
m_pendingFallthrough = false;
}
bool isEmpty()
{
return m_laterFailures.empty() && m_pendingReturns.isEmpty() && !m_pendingFallthrough;
}
// Called at the end of code generation to link all return addresses.
void linkDataLabels(LinkBuffer& linkBuffer)
{
ASSERT(isEmpty());
for (unsigned i = 0; i < m_backtrackRecords.size(); ++i)
linkBuffer.patch(m_backtrackRecords[i].m_dataLabel, linkBuffer.locationOf(m_backtrackRecords[i].m_backtrackLocation));
}
private:
struct ReturnAddressRecord {
ReturnAddressRecord(DataLabelPtr dataLabel, Label backtrackLocation)
: m_dataLabel(dataLabel)
, m_backtrackLocation(backtrackLocation)
{
}
DataLabelPtr m_dataLabel;
Label m_backtrackLocation;
};
JumpList m_laterFailures;
bool m_pendingFallthrough;
Vector<DataLabelPtr, 4> m_pendingReturns;
Vector<ReturnAddressRecord, 4> m_backtrackRecords;
};
// Generation methods:
// ===================
// This method provides a default implementation of backtracking common
// to many terms; terms commonly jump out of the forwards matching path
// on any failed conditions, and add these jumps to the m_jumps list. If
// no special handling is required we can often just backtrack to m_jumps.
void backtrackTermDefault(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
m_backtrackingState.append(op.m_jumps);
}
void generateAssertionBOL(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
if (m_pattern.m_multiline) {
const RegisterID character = regT0;
JumpList matchDest;
if (!term->inputPosition)
matchDest.append(branch32(Equal, index, Imm32(m_checked)));
readCharacter((term->inputPosition - m_checked) - 1, character);
matchCharacterClass(character, matchDest, m_pattern.newlineCharacterClass());
op.m_jumps.append(jump());
matchDest.link(this);
} else {
// Erk, really should poison out these alternatives early. :-/
if (term->inputPosition)
op.m_jumps.append(jump());
else
op.m_jumps.append(branch32(NotEqual, index, Imm32(m_checked)));
}
}
void backtrackAssertionBOL(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
void generateAssertionEOL(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
if (m_pattern.m_multiline) {
const RegisterID character = regT0;
JumpList matchDest;
if (term->inputPosition == m_checked)
matchDest.append(atEndOfInput());
readCharacter(term->inputPosition - m_checked, character);
matchCharacterClass(character, matchDest, m_pattern.newlineCharacterClass());
op.m_jumps.append(jump());
matchDest.link(this);
} else {
if (term->inputPosition == m_checked)
op.m_jumps.append(notAtEndOfInput());
// Erk, really should poison out these alternatives early. :-/
else
op.m_jumps.append(jump());
}
}
void backtrackAssertionEOL(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
// Also falls though on nextIsNotWordChar.
void matchAssertionWordchar(size_t opIndex, JumpList& nextIsWordChar, JumpList& nextIsNotWordChar)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID character = regT0;
if (term->inputPosition == m_checked)
nextIsNotWordChar.append(atEndOfInput());
readCharacter((term->inputPosition - m_checked), character);
matchCharacterClass(character, nextIsWordChar, m_pattern.wordcharCharacterClass());
}
void generateAssertionWordBoundary(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID character = regT0;
Jump atBegin;
JumpList matchDest;
if (!term->inputPosition)
atBegin = branch32(Equal, index, Imm32(m_checked));
readCharacter((term->inputPosition - m_checked) - 1, character);
matchCharacterClass(character, matchDest, m_pattern.wordcharCharacterClass());
if (!term->inputPosition)
atBegin.link(this);
// We fall through to here if the last character was not a wordchar.
JumpList nonWordCharThenWordChar;
JumpList nonWordCharThenNonWordChar;
if (term->invert()) {
matchAssertionWordchar(opIndex, nonWordCharThenNonWordChar, nonWordCharThenWordChar);
nonWordCharThenWordChar.append(jump());
} else {
matchAssertionWordchar(opIndex, nonWordCharThenWordChar, nonWordCharThenNonWordChar);
nonWordCharThenNonWordChar.append(jump());
}
op.m_jumps.append(nonWordCharThenNonWordChar);
// We jump here if the last character was a wordchar.
matchDest.link(this);
JumpList wordCharThenWordChar;
JumpList wordCharThenNonWordChar;
if (term->invert()) {
matchAssertionWordchar(opIndex, wordCharThenNonWordChar, wordCharThenWordChar);
wordCharThenWordChar.append(jump());
} else {
matchAssertionWordchar(opIndex, wordCharThenWordChar, wordCharThenNonWordChar);
// This can fall-though!
}
op.m_jumps.append(wordCharThenWordChar);
nonWordCharThenWordChar.link(this);
wordCharThenNonWordChar.link(this);
}
void backtrackAssertionWordBoundary(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
void generatePatternCharacterOnce(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
if (op.m_isDeadCode)
return;
// m_ops always ends with a OpBodyAlternativeEnd or OpMatchFailed
// node, so there must always be at least one more node.
ASSERT(opIndex + 1 < m_ops.size());
YarrOp* nextOp = &m_ops[opIndex + 1];
PatternTerm* term = op.m_term;
UChar ch = term->patternCharacter;
if ((ch > 0xff) && (m_charSize == Char8)) {
// Have a 16 bit pattern character and an 8 bit string - short circuit
op.m_jumps.append(jump());
return;
}
const RegisterID character = regT0;
int maxCharactersAtOnce = m_charSize == Char8 ? 4 : 2;
unsigned ignoreCaseMask = 0;
int allCharacters = ch;
int numberCharacters;
int startTermPosition = term->inputPosition;
// For case-insesitive compares, non-ascii characters that have different
// upper & lower case representations are converted to a character class.
ASSERT(!m_pattern.m_ignoreCase || isASCIIAlpha(ch) || isCanonicallyUnique(ch));
if (m_pattern.m_ignoreCase && isASCIIAlpha(ch))
ignoreCaseMask |= 32;
for (numberCharacters = 1; numberCharacters < maxCharactersAtOnce && nextOp->m_op == OpTerm; ++numberCharacters, nextOp = &m_ops[opIndex + numberCharacters]) {
PatternTerm* nextTerm = nextOp->m_term;
if (nextTerm->type != PatternTerm::TypePatternCharacter
|| nextTerm->quantityType != QuantifierFixedCount
|| nextTerm->quantityCount != 1
|| nextTerm->inputPosition != (startTermPosition + numberCharacters))
break;
nextOp->m_isDeadCode = true;
int shiftAmount = (m_charSize == Char8 ? 8 : 16) * numberCharacters;
UChar currentCharacter = nextTerm->patternCharacter;
if ((currentCharacter > 0xff) && (m_charSize == Char8)) {
// Have a 16 bit pattern character and an 8 bit string - short circuit
op.m_jumps.append(jump());
return;
}
// For case-insesitive compares, non-ascii characters that have different
// upper & lower case representations are converted to a character class.
ASSERT(!m_pattern.m_ignoreCase || isASCIIAlpha(currentCharacter) || isCanonicallyUnique(currentCharacter));
allCharacters |= (currentCharacter << shiftAmount);
if ((m_pattern.m_ignoreCase) && (isASCIIAlpha(currentCharacter)))
ignoreCaseMask |= 32 << shiftAmount;
}
if (m_charSize == Char8) {
switch (numberCharacters) {
case 1:
op.m_jumps.append(jumpIfCharNotEquals(ch, startTermPosition - m_checked, character));
return;
case 2: {
BaseIndex address(input, index, TimesOne, (startTermPosition - m_checked) * sizeof(LChar));
load16Unaligned(address, character);
break;
}
case 3: {
BaseIndex highAddress(input, index, TimesOne, (startTermPosition - m_checked) * sizeof(LChar));
load16Unaligned(highAddress, character);
if (ignoreCaseMask)
or32(Imm32(ignoreCaseMask), character);
op.m_jumps.append(branch32(NotEqual, character, Imm32((allCharacters & 0xffff) | ignoreCaseMask)));
op.m_jumps.append(jumpIfCharNotEquals(allCharacters >> 16, startTermPosition + 2 - m_checked, character));
return;
}
case 4: {
BaseIndex address(input, index, TimesOne, (startTermPosition - m_checked) * sizeof(LChar));
load32WithUnalignedHalfWords(address, character);
break;
}
}
} else {
switch (numberCharacters) {
case 1:
op.m_jumps.append(jumpIfCharNotEquals(ch, term->inputPosition - m_checked, character));
return;
case 2:
BaseIndex address(input, index, TimesTwo, (term->inputPosition - m_checked) * sizeof(UChar));
load32WithUnalignedHalfWords(address, character);
break;
}
}
if (ignoreCaseMask)
or32(Imm32(ignoreCaseMask), character);
op.m_jumps.append(branch32(NotEqual, character, Imm32(allCharacters | ignoreCaseMask)));
return;
}
void backtrackPatternCharacterOnce(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
void generatePatternCharacterFixed(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
UChar ch = term->patternCharacter;
const RegisterID character = regT0;
const RegisterID countRegister = regT1;
move(index, countRegister);
sub32(Imm32(term->quantityCount.unsafeGet()), countRegister);
Label loop(this);
BaseIndex address(input, countRegister, m_charScale, (Checked<int>(term->inputPosition - m_checked + Checked<int64_t>(term->quantityCount)) * static_cast<int>(m_charSize == Char8 ? sizeof(char) : sizeof(UChar))).unsafeGet());
if (m_charSize == Char8)
load8(address, character);
else
load16(address, character);
// For case-insesitive compares, non-ascii characters that have different
// upper & lower case representations are converted to a character class.
ASSERT(!m_pattern.m_ignoreCase || isASCIIAlpha(ch) || isCanonicallyUnique(ch));
if (m_pattern.m_ignoreCase && isASCIIAlpha(ch)) {
or32(TrustedImm32(0x20), character);
ch |= 0x20;
}
op.m_jumps.append(branch32(NotEqual, character, Imm32(ch)));
add32(TrustedImm32(1), countRegister);
branch32(NotEqual, countRegister, index).linkTo(loop, this);
}
void backtrackPatternCharacterFixed(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
void generatePatternCharacterGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
UChar ch = term->patternCharacter;
const RegisterID character = regT0;
const RegisterID countRegister = regT1;
move(TrustedImm32(0), countRegister);
// Unless have a 16 bit pattern character and an 8 bit string - short circuit
if (!((ch > 0xff) && (m_charSize == Char8))) {
JumpList failures;
Label loop(this);
failures.append(atEndOfInput());
failures.append(jumpIfCharNotEquals(ch, term->inputPosition - m_checked, character));
add32(TrustedImm32(1), countRegister);
add32(TrustedImm32(1), index);
if (term->quantityCount == quantifyInfinite)
jump(loop);
else
branch32(NotEqual, countRegister, Imm32(term->quantityCount.unsafeGet())).linkTo(loop, this);
failures.link(this);
}
op.m_reentry = label();
storeToFrame(countRegister, term->frameLocation);
}
void backtrackPatternCharacterGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID countRegister = regT1;
m_backtrackingState.link(this);
loadFromFrame(term->frameLocation, countRegister);
m_backtrackingState.append(branchTest32(Zero, countRegister));
sub32(TrustedImm32(1), countRegister);
sub32(TrustedImm32(1), index);
jump(op.m_reentry);
}
void generatePatternCharacterNonGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID countRegister = regT1;
move(TrustedImm32(0), countRegister);
op.m_reentry = label();
storeToFrame(countRegister, term->frameLocation);
}
void backtrackPatternCharacterNonGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
UChar ch = term->patternCharacter;
const RegisterID character = regT0;
const RegisterID countRegister = regT1;
m_backtrackingState.link(this);
loadFromFrame(term->frameLocation, countRegister);
// Unless have a 16 bit pattern character and an 8 bit string - short circuit
if (!((ch > 0xff) && (m_charSize == Char8))) {
JumpList nonGreedyFailures;
nonGreedyFailures.append(atEndOfInput());
if (term->quantityCount != quantifyInfinite)
nonGreedyFailures.append(branch32(Equal, countRegister, Imm32(term->quantityCount.unsafeGet())));
nonGreedyFailures.append(jumpIfCharNotEquals(ch, term->inputPosition - m_checked, character));
add32(TrustedImm32(1), countRegister);
add32(TrustedImm32(1), index);
jump(op.m_reentry);
nonGreedyFailures.link(this);
}
sub32(countRegister, index);
m_backtrackingState.fallthrough();
}
void generateCharacterClassOnce(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID character = regT0;
JumpList matchDest;
readCharacter(term->inputPosition - m_checked, character);
matchCharacterClass(character, matchDest, term->characterClass);
if (term->invert())
op.m_jumps.append(matchDest);
else {
op.m_jumps.append(jump());
matchDest.link(this);
}
}
void backtrackCharacterClassOnce(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
void generateCharacterClassFixed(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID character = regT0;
const RegisterID countRegister = regT1;
move(index, countRegister);
sub32(Imm32(term->quantityCount.unsafeGet()), countRegister);
Label loop(this);
JumpList matchDest;
if (m_charSize == Char8)
load8(BaseIndex(input, countRegister, TimesOne, (Checked<int>(term->inputPosition - m_checked + Checked<int64_t>(term->quantityCount)) * static_cast<int>(sizeof(char))).unsafeGet()), character);
else
load16(BaseIndex(input, countRegister, TimesTwo, (Checked<int>(term->inputPosition - m_checked + Checked<int64_t>(term->quantityCount)) * static_cast<int>(sizeof(UChar))).unsafeGet()), character);
matchCharacterClass(character, matchDest, term->characterClass);
if (term->invert())
op.m_jumps.append(matchDest);
else {
op.m_jumps.append(jump());
matchDest.link(this);
}
add32(TrustedImm32(1), countRegister);
branch32(NotEqual, countRegister, index).linkTo(loop, this);
}
void backtrackCharacterClassFixed(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
void generateCharacterClassGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID character = regT0;
const RegisterID countRegister = regT1;
move(TrustedImm32(0), countRegister);
JumpList failures;
Label loop(this);
failures.append(atEndOfInput());
if (term->invert()) {
readCharacter(term->inputPosition - m_checked, character);
matchCharacterClass(character, failures, term->characterClass);
} else {
JumpList matchDest;
readCharacter(term->inputPosition - m_checked, character);
matchCharacterClass(character, matchDest, term->characterClass);
failures.append(jump());
matchDest.link(this);
}
add32(TrustedImm32(1), countRegister);
add32(TrustedImm32(1), index);
if (term->quantityCount != quantifyInfinite) {
branch32(NotEqual, countRegister, Imm32(term->quantityCount.unsafeGet())).linkTo(loop, this);
failures.append(jump());
} else
jump(loop);
failures.link(this);
op.m_reentry = label();
storeToFrame(countRegister, term->frameLocation);
}
void backtrackCharacterClassGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID countRegister = regT1;
m_backtrackingState.link(this);
loadFromFrame(term->frameLocation, countRegister);
m_backtrackingState.append(branchTest32(Zero, countRegister));
sub32(TrustedImm32(1), countRegister);
sub32(TrustedImm32(1), index);
jump(op.m_reentry);
}
void generateCharacterClassNonGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID countRegister = regT1;
move(TrustedImm32(0), countRegister);
op.m_reentry = label();
storeToFrame(countRegister, term->frameLocation);
}
void backtrackCharacterClassNonGreedy(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID character = regT0;
const RegisterID countRegister = regT1;
JumpList nonGreedyFailures;
m_backtrackingState.link(this);
loadFromFrame(term->frameLocation, countRegister);
nonGreedyFailures.append(atEndOfInput());
nonGreedyFailures.append(branch32(Equal, countRegister, Imm32(term->quantityCount.unsafeGet())));
JumpList matchDest;
readCharacter(term->inputPosition - m_checked, character);
matchCharacterClass(character, matchDest, term->characterClass);
if (term->invert())
nonGreedyFailures.append(matchDest);
else {
nonGreedyFailures.append(jump());
matchDest.link(this);
}
add32(TrustedImm32(1), countRegister);
add32(TrustedImm32(1), index);
jump(op.m_reentry);
nonGreedyFailures.link(this);
sub32(countRegister, index);
m_backtrackingState.fallthrough();
}
void generateDotStarEnclosure(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
const RegisterID character = regT0;
const RegisterID matchPos = regT1;
JumpList foundBeginningNewLine;
JumpList saveStartIndex;
JumpList foundEndingNewLine;
ASSERT(!m_pattern.m_body->m_hasFixedSize);
getMatchStart(matchPos);
saveStartIndex.append(branchTest32(Zero, matchPos));
Label findBOLLoop(this);
sub32(TrustedImm32(1), matchPos);
if (m_charSize == Char8)
load8(BaseIndex(input, matchPos, TimesOne, 0), character);
else
load16(BaseIndex(input, matchPos, TimesTwo, 0), character);
matchCharacterClass(character, foundBeginningNewLine, m_pattern.newlineCharacterClass());
branchTest32(NonZero, matchPos).linkTo(findBOLLoop, this);
saveStartIndex.append(jump());
foundBeginningNewLine.link(this);
add32(TrustedImm32(1), matchPos); // Advance past newline
saveStartIndex.link(this);
if (!m_pattern.m_multiline && term->anchors.bolAnchor)
op.m_jumps.append(branchTest32(NonZero, matchPos));
ASSERT(!m_pattern.m_body->m_hasFixedSize);
setMatchStart(matchPos);
move(index, matchPos);
Label findEOLLoop(this);
foundEndingNewLine.append(branch32(Equal, matchPos, length));
if (m_charSize == Char8)
load8(BaseIndex(input, matchPos, TimesOne, 0), character);
else
load16(BaseIndex(input, matchPos, TimesTwo, 0), character);
matchCharacterClass(character, foundEndingNewLine, m_pattern.newlineCharacterClass());
add32(TrustedImm32(1), matchPos);
jump(findEOLLoop);
foundEndingNewLine.link(this);
if (!m_pattern.m_multiline && term->anchors.eolAnchor)
op.m_jumps.append(branch32(NotEqual, matchPos, length));
move(matchPos, index);
}
void backtrackDotStarEnclosure(size_t opIndex)
{
backtrackTermDefault(opIndex);
}
// Code generation/backtracking for simple terms
// (pattern characters, character classes, and assertions).
// These methods farm out work to the set of functions above.
void generateTerm(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
switch (term->type) {
case PatternTerm::TypePatternCharacter:
switch (term->quantityType) {
case QuantifierFixedCount:
if (term->quantityCount == 1)
generatePatternCharacterOnce(opIndex);
else
generatePatternCharacterFixed(opIndex);
break;
case QuantifierGreedy:
generatePatternCharacterGreedy(opIndex);
break;
case QuantifierNonGreedy:
generatePatternCharacterNonGreedy(opIndex);
break;
}
break;
case PatternTerm::TypeCharacterClass:
switch (term->quantityType) {
case QuantifierFixedCount:
if (term->quantityCount == 1)
generateCharacterClassOnce(opIndex);
else
generateCharacterClassFixed(opIndex);
break;
case QuantifierGreedy:
generateCharacterClassGreedy(opIndex);
break;
case QuantifierNonGreedy:
generateCharacterClassNonGreedy(opIndex);
break;
}
break;
case PatternTerm::TypeAssertionBOL:
generateAssertionBOL(opIndex);
break;
case PatternTerm::TypeAssertionEOL:
generateAssertionEOL(opIndex);
break;
case PatternTerm::TypeAssertionWordBoundary:
generateAssertionWordBoundary(opIndex);
break;
case PatternTerm::TypeForwardReference:
break;
case PatternTerm::TypeParenthesesSubpattern:
case PatternTerm::TypeParentheticalAssertion:
ASSERT_NOT_REACHED();
case PatternTerm::TypeBackReference:
m_shouldFallBack = true;
break;
case PatternTerm::TypeDotStarEnclosure:
generateDotStarEnclosure(opIndex);
break;
}
}
void backtrackTerm(size_t opIndex)
{
YarrOp& op = m_ops[opIndex];
PatternTerm* term = op.m_term;
switch (term->type) {
case PatternTerm::TypePatternCharacter:
switch (term->quantityType) {
case QuantifierFixedCount:
if (term->quantityCount == 1)
backtrackPatternCharacterOnce(opIndex);
else
backtrackPatternCharacterFixed(opIndex);
break;
case QuantifierGreedy:
backtrackPatternCharacterGreedy(opIndex);
break;
case QuantifierNonGreedy:
backtrackPatternCharacterNonGreedy(opIndex);
break;
}
break;
case PatternTerm::TypeCharacterClass:
switch (term->quantityType) {
case QuantifierFixedCount:
if (term->quantityCount == 1)
backtrackCharacterClassOnce(opIndex);
else
backtrackCharacterClassFixed(opIndex);
break;
case QuantifierGreedy:
backtrackCharacterClassGreedy(opIndex);
break;
case QuantifierNonGreedy:
backtrackCharacterClassNonGreedy(opIndex);
break;
}
break;
case PatternTerm::TypeAssertionBOL:
backtrackAssertionBOL(opIndex);
break;
case PatternTerm::TypeAssertionEOL:
backtrackAssertionEOL(opIndex);
break;
case PatternTerm::TypeAssertionWordBoundary:
backtrackAssertionWordBoundary(opIndex);
break;
case PatternTerm::TypeForwardReference:
break;
case PatternTerm::TypeParenthesesSubpattern:
case PatternTerm::TypeParentheticalAssertion:
ASSERT_NOT_REACHED();
case PatternTerm::TypeDotStarEnclosure:
backtrackDotStarEnclosure(opIndex);
break;
case PatternTerm::TypeBackReference:
m_shouldFallBack = true;
break;
}
}
void generate()
{
// Forwards generate the matching code.
ASSERT(m_ops.size());
size_t opIndex = 0;
do {
YarrOp& op = m_ops[opIndex];
switch (op.m_op) {
case OpTerm:
generateTerm(opIndex);
break;
// OpBodyAlternativeBegin/Next/End
//
// These nodes wrap the set of alternatives in the body of the regular expression.
// There may be either one or two chains of OpBodyAlternative nodes, one representing
// the 'once through' sequence of alternatives (if any exist), and one representing
// the repeating alternatives (again, if any exist).
//
// Upon normal entry to the Begin alternative, we will check that input is available.
// Reentry to the Begin alternative will take place after the check has taken place,
// and will assume that the input position has already been progressed as appropriate.
//
// Entry to subsequent Next/End alternatives occurs when the prior alternative has
// successfully completed a match - return a success state from JIT code.
//
// Next alternatives allow for reentry optimized to suit backtracking from its
// preceding alternative. It expects the input position to still be set to a position
// appropriate to its predecessor, and it will only perform an input check if the
// predecessor had a minimum size less than its own.
//
// In the case 'once through' expressions, the End node will also have a reentry
// point to jump to when the last alternative fails. Again, this expects the input
// position to still reflect that expected by the prior alternative.
case OpBodyAlternativeBegin: {
PatternAlternative* alternative = op.m_alternative;
// Upon entry at the head of the set of alternatives, check if input is available
// to run the first alternative. (This progresses the input position).
op.m_jumps.append(jumpIfNoAvailableInput(alternative->m_minimumSize));
// We will reenter after the check, and assume the input position to have been
// set as appropriate to this alternative.
op.m_reentry = label();
m_checked += alternative->m_minimumSize;
break;
}
case OpBodyAlternativeNext:
case OpBodyAlternativeEnd: {
PatternAlternative* priorAlternative = m_ops[op.m_previousOp].m_alternative;
PatternAlternative* alternative = op.m_alternative;
// If we get here, the prior alternative matched - return success.
// Adjust the stack pointer to remove the pattern's frame.
removeCallFrame();
// Load appropriate values into the return register and the first output
// slot, and return. In the case of pattern with a fixed size, we will
// not have yet set the value in the first
ASSERT(index != returnRegister);
if (m_pattern.m_body->m_hasFixedSize) {
move(index, returnRegister);
if (priorAlternative->m_minimumSize)
sub32(Imm32(priorAlternative->m_minimumSize), returnRegister);
if (compileMode == IncludeSubpatterns)
store32(returnRegister, output);
} else
getMatchStart(returnRegister);
if (compileMode == IncludeSubpatterns)
store32(index, Address(output, 4));
move(index, returnRegister2);
generateReturn();
// This is the divide between the tail of the prior alternative, above, and
// the head of the subsequent alternative, below.
if (op.m_op == OpBodyAlternativeNext) {
// This is the reentry point for the Next alternative. We expect any code
// that jumps here to do so with the input position matching that of the
// PRIOR alteranative, and we will only check input availability if we
// need to progress it forwards.
op.m_reentry = label();
if (alternative->m_minimumSize > priorAlternative->m_minimumSize) {
add32(Imm32(alternative->m_minimumSize - priorAlternative->m_minimumSize), index);
op.m_jumps.append(jumpIfNoAvailableInput());
} else if (priorAlternative->m_minimumSize > alternative->m_minimumSize)
sub32(Imm32(priorAlternative->m_minimumSize - alternative->m_minimumSize), index);
} else if (op.m_nextOp == notFound) {
// This is the reentry point for the End of 'once through' alternatives,
// jumped to when the last alternative fails to match.
op.m_reentry = label();
sub32(Imm32(priorAlternative->m_minimumSize), index);
}
if (op.m_op == OpBodyAlternativeNext)
m_checked += alternative->m_minimumSize;
m_checked -= priorAlternative->m_minimumSize;
break;
}
// OpSimpleNestedAlternativeBegin/Next/End
// OpNestedAlternativeBegin/Next/End
//
// These nodes are used to handle sets of alternatives that are nested within
// subpatterns and parenthetical assertions. The 'simple' forms are used where
// we do not need to be able to backtrack back into any alternative other than
// the last, the normal forms allow backtracking into any alternative.
//
// Each Begin/Next node is responsible for planting an input check to ensure
// sufficient input is available on entry. Next nodes additionally need to
// jump to the end - Next nodes use the End node's m_jumps list to hold this
// set of jumps.
//
// In the non-simple forms, successful alternative matches must store a
// 'return address' using a DataLabelPtr, used to store the address to jump
// to when backtracking, to get to the code for the appropriate alternative.
case OpSimpleNestedAlternativeBegin:
case OpNestedAlternativeBegin: {
PatternTerm* term = op.m_term;
PatternAlternative* alternative = op.m_alternative;
PatternDisjunction* disjunction = term->parentheses.disjunction;
// Calculate how much input we need to check for, and if non-zero check.
op.m_checkAdjust = alternative->m_minimumSize;
if ((term->quantityType == QuantifierFixedCount) && (term->type != PatternTerm::TypeParentheticalAssertion))
op.m_checkAdjust -= disjunction->m_minimumSize;
if (op.m_checkAdjust)
op.m_jumps.append(jumpIfNoAvailableInput(op.m_checkAdjust));
m_checked += op.m_checkAdjust;
break;
}
case OpSimpleNestedAlternativeNext:
case OpNestedAlternativeNext: {
PatternTerm* term = op.m_term;
PatternAlternative* alternative = op.m_alternative;
PatternDisjunction* disjunction = term->parentheses.disjunction;
// In the non-simple case, store a 'return address' so we can backtrack correctly.
if (op.m_op == OpNestedAlternativeNext) {
unsigned parenthesesFrameLocation = term->frameLocation;
unsigned alternativeFrameLocation = parenthesesFrameLocation;
if (term->quantityType != QuantifierFixedCount)
alternativeFrameLocation += YarrStackSpaceForBackTrackInfoParenthesesOnce;
op.m_returnAddress = storeToFrameWithPatch(alternativeFrameLocation);
}
if (term->quantityType != QuantifierFixedCount && !m_ops[op.m_previousOp].m_alternative->m_minimumSize) {
// If the previous alternative matched without consuming characters then
// backtrack to try to match while consumming some input.
op.m_zeroLengthMatch = branch32(Equal, index, Address(stackPointerRegister, term->frameLocation * sizeof(void*)));
}
// If we reach here then the last alternative has matched - jump to the
// End node, to skip over any further alternatives.
//
// FIXME: this is logically O(N^2) (though N can be expected to be very
// small). We could avoid this either by adding an extra jump to the JIT
// data structures, or by making backtracking code that jumps to Next
// alternatives are responsible for checking that input is available (if
// we didn't need to plant the input checks, then m_jumps would be free).
YarrOp* endOp = &m_ops[op.m_nextOp];
while (endOp->m_nextOp != notFound) {
ASSERT(endOp->m_op == OpSimpleNestedAlternativeNext || endOp->m_op == OpNestedAlternativeNext);
endOp = &m_ops[endOp->m_nextOp];
}
ASSERT(endOp->m_op == OpSimpleNestedAlternativeEnd || endOp->m_op == OpNestedAlternativeEnd);
endOp->m_jumps.append(jump());
// This is the entry point for the next alternative.
op.m_reentry = label();
// Calculate how much input we need to check for, and if non-zero check.
op.m_checkAdjust = alternative->m_minimumSize;
if ((term->quantityType == QuantifierFixedCount) && (term->type != PatternTerm::TypeParentheticalAssertion))
op.m_checkAdjust -= disjunction->m_minimumSize;
if (op.m_checkAdjust)
op.m_jumps.append(jumpIfNoAvailableInput(op.m_checkAdjust));
YarrOp& lastOp = m_ops[op.m_previousOp];
m_checked -= lastOp.m_checkAdjust;
m_checked += op.m_checkAdjust;
break;
}
case OpSimpleNestedAlternativeEnd:
case OpNestedAlternativeEnd: {
PatternTerm* term = op.m_term;
// In the non-simple case, store a 'return address' so we can backtrack correctly.
if (op.m_op == OpNestedAlternativeEnd) {
unsigned parenthesesFrameLocation = term->frameLocation;
unsigned alternativeFrameLocation = parenthesesFrameLocation;
if (term->quantityType != QuantifierFixedCount)
alternativeFrameLocation += YarrStackSpaceForBackTrackInfoParenthesesOnce;
op.m_returnAddress = storeToFrameWithPatch(alternativeFrameLocation);
}
if (term->quantityType != QuantifierFixedCount && !m_ops[op.m_previousOp].m_alternative->m_minimumSize) {
// If the previous alternative matched without consuming characters then
// backtrack to try to match while consumming some input.
op.m_zeroLengthMatch = branch32(Equal, index, Address(stackPointerRegister, term->frameLocation * sizeof(void*)));
}
// If this set of alternatives contains more than one alternative,
// then the Next nodes will have planted jumps to the End, and added
// them to this node's m_jumps list.
op.m_jumps.link(this);
op.m_jumps.clear();
YarrOp& lastOp = m_ops[op.m_previousOp];
m_checked -= lastOp.m_checkAdjust;
break;
}
// OpParenthesesSubpatternOnceBegin/End
//
// These nodes support (optionally) capturing subpatterns, that have a
// quantity count of 1 (this covers fixed once, and ?/?? quantifiers).
case OpParenthesesSubpatternOnceBegin: {
PatternTerm* term = op.m_term;
unsigned parenthesesFrameLocation = term->frameLocation;
const RegisterID indexTemporary = regT0;
ASSERT(term->quantityCount == 1);
// Upon entry to a Greedy quantified set of parenthese store the index.
// We'll use this for two purposes:
// - To indicate which iteration we are on of mathing the remainder of
// the expression after the parentheses - the first, including the
// match within the parentheses, or the second having skipped over them.
// - To check for empty matches, which must be rejected.
//
// At the head of a NonGreedy set of parentheses we'll immediately set the
// value on the stack to -1 (indicating a match skipping the subpattern),
// and plant a jump to the end. We'll also plant a label to backtrack to
// to reenter the subpattern later, with a store to set up index on the
// second iteration.
//
// FIXME: for capturing parens, could use the index in the capture array?
if (term->quantityType == QuantifierGreedy)
storeToFrame(index, parenthesesFrameLocation);
else if (term->quantityType == QuantifierNonGreedy) {
storeToFrame(TrustedImm32(-1), parenthesesFrameLocation);
op.m_jumps.append(jump());
op.m_reentry = label();
storeToFrame(index, parenthesesFrameLocation);
}
// If the parenthese are capturing, store the starting index value to the
// captures array, offsetting as necessary.
//
// FIXME: could avoid offsetting this value in JIT code, apply
// offsets only afterwards, at the point the results array is
// being accessed.
if (term->capture() && compileMode == IncludeSubpatterns) {
int inputOffset = term->inputPosition - m_checked;
if (term->quantityType == QuantifierFixedCount)
inputOffset -= term->parentheses.disjunction->m_minimumSize;
if (inputOffset) {
move(index, indexTemporary);
add32(Imm32(inputOffset), indexTemporary);
setSubpatternStart(indexTemporary, term->parentheses.subpatternId);
} else
setSubpatternStart(index, term->parentheses.subpatternId);
}
break;
}
case OpParenthesesSubpatternOnceEnd: {
PatternTerm* term = op.m_term;
const RegisterID indexTemporary = regT0;
ASSERT(term->quantityCount == 1);
#ifndef NDEBUG
// Runtime ASSERT to make sure that the nested alternative handled the
// "no input consumed" check.
if (term->quantityType != QuantifierFixedCount && !term->parentheses.disjunction->m_minimumSize) {
Jump pastBreakpoint;
pastBreakpoint = branch32(NotEqual, index, Address(stackPointerRegister, term->frameLocation * sizeof(void*)));
breakpoint();
pastBreakpoint.link(this);
}
#endif
// If the parenthese are capturing, store the ending index value to the
// captures array, offsetting as necessary.
//
// FIXME: could avoid offsetting this value in JIT code, apply
// offsets only afterwards, at the point the results array is
// being accessed.
if (term->capture() && compileMode == IncludeSubpatterns) {
int inputOffset = term->inputPosition - m_checked;
if (inputOffset) {
move(index, indexTemporary);
add32(Imm32(inputOffset), indexTemporary);
setSubpatternEnd(indexTemporary, term->parentheses.subpatternId);
} else
setSubpatternEnd(index, term->parentheses.subpatternId);
}
// If the parentheses are quantified Greedy then add a label to jump back
// to if get a failed match from after the parentheses. For NonGreedy
// parentheses, link the jump from before the subpattern to here.
if (term->quantityType == QuantifierGreedy)
op.m_reentry = label();
else if (term->quantityType == QuantifierNonGreedy) {
YarrOp& beginOp = m_ops[op.m_previousOp];
beginOp.m_jumps.link(this);
}
break;
}
// OpParenthesesSubpatternTerminalBegin/End
case OpParenthesesSubpatternTerminalBegin: {
PatternTerm* term = op.m_term;
ASSERT(term->quantityType == QuantifierGreedy);
ASSERT(term->quantityCount == quantifyInfinite);
ASSERT(!term->capture());
// Upon entry set a label to loop back to.
op.m_reentry = label();
// Store the start index of the current match; we need to reject zero
// length matches.
storeToFrame(index, term->frameLocation);
break;
}
case OpParenthesesSubpatternTerminalEnd: {
YarrOp& beginOp = m_ops[op.m_previousOp];
#ifndef NDEBUG
PatternTerm* term = op.m_term;
// Runtime ASSERT to make sure that the nested alternative handled the
// "no input consumed" check.
Jump pastBreakpoint;
pastBreakpoint = branch32(NotEqual, index, Address(stackPointerRegister, term->frameLocation * sizeof(void*)));
breakpoint();
pastBreakpoint.link(this);
#endif
// We know that the match is non-zero, we can accept it and
// loop back up to the head of the subpattern.
jump(beginOp.m_reentry);
// This is the entry point to jump to when we stop matching - we will
// do so once the subpattern cannot match any more.
op.m_reentry = label();
break;
}
// OpParentheticalAssertionBegin/End
case OpParentheticalAssertionBegin: {
PatternTerm* term = op.m_term;
// Store the current index - assertions should not update index, so
// we will need to restore it upon a successful match.
unsigned parenthesesFrameLocation = term->frameLocation;
storeToFrame(index, parenthesesFrameLocation);
// Check
op.m_checkAdjust = m_checked - term->inputPosition;
if (op.m_checkAdjust)
sub32(Imm32(op.m_checkAdjust), index);
m_checked -= op.m_checkAdjust;
break;
}
case OpParentheticalAssertionEnd: {
PatternTerm* term = op.m_term;
// Restore the input index value.
unsigned parenthesesFrameLocation = term->frameLocation;
loadFromFrame(parenthesesFrameLocation, index);
// If inverted, a successful match of the assertion must be treated
// as a failure, so jump to backtracking.
if (term->invert()) {
op.m_jumps.append(jump());
op.m_reentry = label();
}
YarrOp& lastOp = m_ops[op.m_previousOp];
m_checked += lastOp.m_checkAdjust;
break;
}
case OpMatchFailed:
removeCallFrame();
move(TrustedImmPtr((void*)WTF::notFound), returnRegister);
move(TrustedImm32(0), returnRegister2);
generateReturn();
break;
}
++opIndex;
} while (opIndex < m_ops.size());
}
void backtrack()
{
// Backwards generate the backtracking code.
size_t opIndex = m_ops.size();
ASSERT(opIndex);
do {
--opIndex;
YarrOp& op = m_ops[opIndex];
switch (op.m_op) {
case OpTerm:
backtrackTerm(opIndex);
break;
// OpBodyAlternativeBegin/Next/End
//
// For each Begin/Next node representing an alternative, we need to decide what to do
// in two circumstances:
// - If we backtrack back into this node, from within the alternative.
// - If the input check at the head of the alternative fails (if this exists).
//
// We treat these two cases differently since in the former case we have slightly
// more information - since we are backtracking out of a prior alternative we know
// that at least enough input was available to run it. For example, given the regular
// expression /a|b/, if we backtrack out of the first alternative (a failed pattern
// character match of 'a'), then we need not perform an additional input availability
// check before running the second alternative.
//
// Backtracking required differs for the last alternative, which in the case of the
// repeating set of alternatives must loop. The code generated for the last alternative
// will also be used to handle all input check failures from any prior alternatives -
// these require similar functionality, in seeking the next available alternative for
// which there is sufficient input.
//
// Since backtracking of all other alternatives simply requires us to link backtracks
// to the reentry point for the subsequent alternative, we will only be generating any
// code when backtracking the last alternative.
case OpBodyAlternativeBegin:
case OpBodyAlternativeNext: {
PatternAlternative* alternative = op.m_alternative;
if (op.m_op == OpBodyAlternativeNext) {
PatternAlternative* priorAlternative = m_ops[op.m_previousOp].m_alternative;
m_checked += priorAlternative->m_minimumSize;
}
m_checked -= alternative->m_minimumSize;
// Is this the last alternative? If not, then if we backtrack to this point we just
// need to jump to try to match the next alternative.
if (m_ops[op.m_nextOp].m_op != OpBodyAlternativeEnd) {
m_backtrackingState.linkTo(m_ops[op.m_nextOp].m_reentry, this);
break;
}
YarrOp& endOp = m_ops[op.m_nextOp];
YarrOp* beginOp = &op;
while (beginOp->m_op != OpBodyAlternativeBegin) {
ASSERT(beginOp->m_op == OpBodyAlternativeNext);
beginOp = &m_ops[beginOp->m_previousOp];
}
bool onceThrough = endOp.m_nextOp == notFound;
// First, generate code to handle cases where we backtrack out of an attempted match
// of the last alternative. If this is a 'once through' set of alternatives then we
// have nothing to do - link this straight through to the End.
if (onceThrough)
m_backtrackingState.linkTo(endOp.m_reentry, this);
else {
// If we don't need to move the input poistion, and the pattern has a fixed size
// (in which case we omit the store of the start index until the pattern has matched)
// then we can just link the backtrack out of the last alternative straight to the
// head of the first alternative.
if (m_pattern.m_body->m_hasFixedSize
&& (alternative->m_minimumSize > beginOp->m_alternative->m_minimumSize)
&& (alternative->m_minimumSize - beginOp->m_alternative->m_minimumSize == 1))
m_backtrackingState.linkTo(beginOp->m_reentry, this);
else {
// We need to generate a trampoline of code to execute before looping back
// around to the first alternative.
m_backtrackingState.link(this);
// If the pattern size is not fixed, then store the start index, for use if we match.
if (!m_pattern.m_body->m_hasFixedSize) {
if (alternative->m_minimumSize == 1)
setMatchStart(index);
else {
move(index, regT0);
if (alternative->m_minimumSize)
sub32(Imm32(alternative->m_minimumSize - 1), regT0);
else
add32(TrustedImm32(1), regT0);
setMatchStart(regT0);
}
}
// Generate code to loop. Check whether the last alternative is longer than the
// first (e.g. /a|xy/ or /a|xyz/).
if (alternative->m_minimumSize > beginOp->m_alternative->m_minimumSize) {
// We want to loop, and increment input position. If the delta is 1, it is
// already correctly incremented, if more than one then decrement as appropriate.
unsigned delta = alternative->m_minimumSize - beginOp->m_alternative->m_minimumSize;
ASSERT(delta);
if (delta != 1)
sub32(Imm32(delta - 1), index);
jump(beginOp->m_reentry);
} else {
// If the first alternative has minimum size 0xFFFFFFFFu, then there cannot
// be sufficent input available to handle this, so just fall through.
unsigned delta = beginOp->m_alternative->m_minimumSize - alternative->m_minimumSize;
if (delta != 0xFFFFFFFFu) {
// We need to check input because we are incrementing the input.
add32(Imm32(delta + 1), index);
checkInput().linkTo(beginOp->m_reentry, this);
}
}
}
}
// We can reach this point in the code in two ways:
// - Fallthrough from the code above (a repeating alternative backtracked out of its
// last alternative, and did not have sufficent input to run the first).
// - We will loop back up to the following label when a releating alternative loops,
// following a failed input check.
//
// Either way, we have just failed the input check for the first alternative.
Label firstInputCheckFailed(this);
// Generate code to handle input check failures from alternatives except the last.
// prevOp is the alternative we're handling a bail out from (initially Begin), and
// nextOp is the alternative we will be attempting to reenter into.
//
// We will link input check failures from the forwards matching path back to the code
// that can handle them.
YarrOp* prevOp = beginOp;
YarrOp* nextOp = &m_ops[beginOp->m_nextOp];
while (nextOp->m_op != OpBodyAlternativeEnd) {
prevOp->m_jumps.link(this);
// We only get here if an input check fails, it is only worth checking again
// if the next alternative has a minimum size less than the last.
if (prevOp->m_alternative->m_minimumSize > nextOp->m_alternative->m_minimumSize) {
// FIXME: if we added an extra label to YarrOp, we could avoid needing to
// subtract delta back out, and reduce this code. Should performance test
// the benefit of this.
unsigned delta = prevOp->m_alternative->m_minimumSize - nextOp->m_alternative->m_minimumSize;
sub32(Imm32(delta), index);
Jump fail = jumpIfNoAvailableInput();
add32(Imm32(delta), index);
jump(nextOp->m_reentry);
fail.link(this);
} else if (prevOp->m_alternative->m_minimumSize < nextOp->m_alternative->m_minimumSize)
add32(Imm32(nextOp->m_alternative->m_minimumSize - prevOp->m_alternative->m_minimumSize), index);
prevOp = nextOp;
nextOp = &m_ops[nextOp->m_nextOp];
}
// We fall through to here if there is insufficient input to run the last alternative.
// If there is insufficient input to run the last alternative, then for 'once through'
// alternatives we are done - just jump back up into the forwards matching path at the End.
if (onceThrough) {
op.m_jumps.linkTo(endOp.m_reentry, this);
jump(endOp.m_reentry);
break;
}
// For repeating alternatives, link any input check failure from the last alternative to
// this point.
op.m_jumps.link(this);
bool needsToUpdateMatchStart = !m_pattern.m_body->m_hasFixedSize;
// Check for cases where input position is already incremented by 1 for the last
// alternative (this is particularly useful where the minimum size of the body
// disjunction is 0, e.g. /a*|b/).
if (needsToUpdateMatchStart && alternative->m_minimumSize == 1) {
// index is already incremented by 1, so just store it now!
setMatchStart(index);
needsToUpdateMatchStart = false;
}
// Check whether there is sufficient input to loop. Increment the input position by
// one, and check. Also add in the minimum disjunction size before checking - there
// is no point in looping if we're just going to fail all the input checks around
// the next iteration.
ASSERT(alternative->m_minimumSize >= m_pattern.m_body->m_minimumSize);
if (alternative->m_minimumSize == m_pattern.m_body->m_minimumSize) {
// If the last alternative had the same minimum size as the disjunction,
// just simply increment input pos by 1, no adjustment based on minimum size.
add32(TrustedImm32(1), index);
} else {
// If the minumum for the last alternative was one greater than than that
// for the disjunction, we're already progressed by 1, nothing to do!
unsigned delta = (alternative->m_minimumSize - m_pattern.m_body->m_minimumSize) - 1;
if (delta)
sub32(Imm32(delta), index);
}
Jump matchFailed = jumpIfNoAvailableInput();
if (needsToUpdateMatchStart) {
if (!m_pattern.m_body->m_minimumSize)
setMatchStart(index);
else {
move(index, regT0);
sub32(Imm32(m_pattern.m_body->m_minimumSize), regT0);
setMatchStart(regT0);
}
}
// Calculate how much more input the first alternative requires than the minimum
// for the body as a whole. If no more is needed then we dont need an additional
// input check here - jump straight back up to the start of the first alternative.
if (beginOp->m_alternative->m_minimumSize == m_pattern.m_body->m_minimumSize)
jump(beginOp->m_reentry);
else {
if (beginOp->m_alternative->m_minimumSize > m_pattern.m_body->m_minimumSize)
add32(Imm32(beginOp->m_alternative->m_minimumSize - m_pattern.m_body->m_minimumSize), index);
else
sub32(Imm32(m_pattern.m_body->m_minimumSize - beginOp->m_alternative->m_minimumSize), index);
checkInput().linkTo(beginOp->m_reentry, this);
jump(firstInputCheckFailed);
}
// We jump to here if we iterate to the point that there is insufficient input to
// run any matches, and need to return a failure state from JIT code.
matchFailed.link(this);
removeCallFrame();
move(TrustedImmPtr((void*)WTF::notFound), returnRegister);
move(TrustedImm32(0), returnRegister2);
generateReturn();
break;
}
case OpBodyAlternativeEnd: {
// We should never backtrack back into a body disjunction.
ASSERT(m_backtrackingState.isEmpty());
PatternAlternative* priorAlternative = m_ops[op.m_previousOp].m_alternative;
m_checked += priorAlternative->m_minimumSize;
break;
}
// OpSimpleNestedAlternativeBegin/Next/End
// OpNestedAlternativeBegin/Next/End
//
// Generate code for when we backtrack back out of an alternative into
// a Begin or Next node, or when the entry input count check fails. If
// there are more alternatives we need to jump to the next alternative,
// if not we backtrack back out of the current set of parentheses.
//
// In the case of non-simple nested assertions we need to also link the
// 'return address' appropriately to backtrack back out into the correct
// alternative.
case OpSimpleNestedAlternativeBegin:
case OpSimpleNestedAlternativeNext:
case OpNestedAlternativeBegin:
case OpNestedAlternativeNext: {
YarrOp& nextOp = m_ops[op.m_nextOp];
bool isBegin = op.m_previousOp == notFound;
bool isLastAlternative = nextOp.m_nextOp == notFound;
ASSERT(isBegin == (op.m_op == OpSimpleNestedAlternativeBegin || op.m_op == OpNestedAlternativeBegin));
ASSERT(isLastAlternative == (nextOp.m_op == OpSimpleNestedAlternativeEnd || nextOp.m_op == OpNestedAlternativeEnd));
// Treat an input check failure the same as a failed match.
m_backtrackingState.append(op.m_jumps);
// Set the backtracks to jump to the appropriate place. We may need
// to link the backtracks in one of three different way depending on
// the type of alternative we are dealing with:
// - A single alternative, with no simplings.
// - The last alternative of a set of two or more.
// - An alternative other than the last of a set of two or more.
//
// In the case of a single alternative on its own, we don't need to
// jump anywhere - if the alternative fails to match we can just
// continue to backtrack out of the parentheses without jumping.
//
// In the case of the last alternative in a set of more than one, we
// need to jump to return back out to the beginning. We'll do so by
// adding a jump to the End node's m_jumps list, and linking this
// when we come to generate the Begin node. For alternatives other
// than the last, we need to jump to the next alternative.
//
// If the alternative had adjusted the input position we must link
// backtracking to here, correct, and then jump on. If not we can
// link the backtracks directly to their destination.
if (op.m_checkAdjust) {
// Handle the cases where we need to link the backtracks here.
m_backtrackingState.link(this);
sub32(Imm32(op.m_checkAdjust), index);
if (!isLastAlternative) {
// An alternative that is not the last should jump to its successor.
jump(nextOp.m_reentry);
} else if (!isBegin) {
// The last of more than one alternatives must jump back to the beginning.
nextOp.m_jumps.append(jump());
} else {
// A single alternative on its own can fall through.
m_backtrackingState.fallthrough();
}
} else {
// Handle the cases where we can link the backtracks directly to their destinations.
if (!isLastAlternative) {
// An alternative that is not the last should jump to its successor.
m_backtrackingState.linkTo(nextOp.m_reentry, this);
} else if (!isBegin) {
// The last of more than one alternatives must jump back to the beginning.
m_backtrackingState.takeBacktracksToJumpList(nextOp.m_jumps, this);
}
// In the case of a single alternative on its own do nothing - it can fall through.
}
// If there is a backtrack jump from a zero length match link it here.
if (op.m_zeroLengthMatch.isSet())
m_backtrackingState.append(op.m_zeroLengthMatch);
// At this point we've handled the backtracking back into this node.
// Now link any backtracks that need to jump to here.
// For non-simple alternatives, link the alternative's 'return address'
// so that we backtrack back out into the previous alternative.
if (op.m_op == OpNestedAlternativeNext)
m_backtrackingState.append(op.m_returnAddress);
// If there is more than one alternative, then the last alternative will
// have planted a jump to be linked to the end. This jump was added to the
// End node's m_jumps list. If we are back at the beginning, link it here.
if (isBegin) {
YarrOp* endOp = &m_ops[op.m_nextOp];
while (endOp->m_nextOp != notFound) {
ASSERT(endOp->m_op == OpSimpleNestedAlternativeNext || endOp->m_op == OpNestedAlternativeNext);
endOp = &m_ops[endOp->m_nextOp];
}
ASSERT(endOp->m_op == OpSimpleNestedAlternativeEnd || endOp->m_op == OpNestedAlternativeEnd);
m_backtrackingState.append(endOp->m_jumps);
}
if (!isBegin) {
YarrOp& lastOp = m_ops[op.m_previousOp];
m_checked += lastOp.m_checkAdjust;
}
m_checked -= op.m_checkAdjust;
break;
}
case OpSimpleNestedAlternativeEnd:
case OpNestedAlternativeEnd: {
PatternTerm* term = op.m_term;
// If there is a backtrack jump from a zero length match link it here.
if (op.m_zeroLengthMatch.isSet())
m_backtrackingState.append(op.m_zeroLengthMatch);
// If we backtrack into the end of a simple subpattern do nothing;
// just continue through into the last alternative. If we backtrack
// into the end of a non-simple set of alterntives we need to jump
// to the backtracking return address set up during generation.
if (op.m_op == OpNestedAlternativeEnd) {
m_backtrackingState.link(this);
// Plant a jump to the return address.
unsigned parenthesesFrameLocation = term->frameLocation;
unsigned alternativeFrameLocation = parenthesesFrameLocation;
if (term->quantityType != QuantifierFixedCount)
alternativeFrameLocation += YarrStackSpaceForBackTrackInfoParenthesesOnce;
loadFromFrameAndJump(alternativeFrameLocation);
// Link the DataLabelPtr associated with the end of the last
// alternative to this point.
m_backtrackingState.append(op.m_returnAddress);
}
YarrOp& lastOp = m_ops[op.m_previousOp];
m_checked += lastOp.m_checkAdjust;
break;
}
// OpParenthesesSubpatternOnceBegin/End
//
// When we are backtracking back out of a capturing subpattern we need
// to clear the start index in the matches output array, to record that
// this subpattern has not been captured.
//
// When backtracking back out of a Greedy quantified subpattern we need
// to catch this, and try running the remainder of the alternative after
// the subpattern again, skipping the parentheses.
//
// Upon backtracking back into a quantified set of parentheses we need to
// check whether we were currently skipping the subpattern. If not, we
// can backtrack into them, if we were we need to either backtrack back
// out of the start of the parentheses, or jump back to the forwards
// matching start, depending of whether the match is Greedy or NonGreedy.
case OpParenthesesSubpatternOnceBegin: {
PatternTerm* term = op.m_term;
ASSERT(term->quantityCount == 1);
// We only need to backtrack to thispoint if capturing or greedy.
if ((term->capture() && compileMode == IncludeSubpatterns) || term->quantityType == QuantifierGreedy) {
m_backtrackingState.link(this);
// If capturing, clear the capture (we only need to reset start).
if (term->capture() && compileMode == IncludeSubpatterns)
clearSubpatternStart(term->parentheses.subpatternId);
// If Greedy, jump to the end.
if (term->quantityType == QuantifierGreedy) {
// Clear the flag in the stackframe indicating we ran through the subpattern.
unsigned parenthesesFrameLocation = term->frameLocation;
storeToFrame(TrustedImm32(-1), parenthesesFrameLocation);
// Jump to after the parentheses, skipping the subpattern.
jump(m_ops[op.m_nextOp].m_reentry);
// A backtrack from after the parentheses, when skipping the subpattern,
// will jump back to here.
op.m_jumps.link(this);
}
m_backtrackingState.fallthrough();
}
break;
}
case OpParenthesesSubpatternOnceEnd: {
PatternTerm* term = op.m_term;
if (term->quantityType != QuantifierFixedCount) {
m_backtrackingState.link(this);
// Check whether we should backtrack back into the parentheses, or if we
// are currently in a state where we had skipped over the subpattern
// (in which case the flag value on the stack will be -1).
unsigned parenthesesFrameLocation = term->frameLocation;
Jump hadSkipped = branch32(Equal, Address(stackPointerRegister, parenthesesFrameLocation * sizeof(void*)), TrustedImm32(-1));
if (term->quantityType == QuantifierGreedy) {
// For Greedy parentheses, we skip after having already tried going
// through the subpattern, so if we get here we're done.
YarrOp& beginOp = m_ops[op.m_previousOp];
beginOp.m_jumps.append(hadSkipped);
} else {
// For NonGreedy parentheses, we try skipping the subpattern first,
// so if we get here we need to try running through the subpattern
// next. Jump back to the start of the parentheses in the forwards
// matching path.
ASSERT(term->quantityType == QuantifierNonGreedy);
YarrOp& beginOp = m_ops[op.m_previousOp];
hadSkipped.linkTo(beginOp.m_reentry, this);
}
m_backtrackingState.fallthrough();
}
m_backtrackingState.append(op.m_jumps);
break;
}
// OpParenthesesSubpatternTerminalBegin/End
//
// Terminal subpatterns will always match - there is nothing after them to
// force a backtrack, and they have a minimum count of 0, and as such will
// always produce an acceptable result.
case OpParenthesesSubpatternTerminalBegin: {
// We will backtrack to this point once the subpattern cannot match any
// more. Since no match is accepted as a successful match (we are Greedy
// quantified with a minimum of zero) jump back to the forwards matching
// path at the end.
YarrOp& endOp = m_ops[op.m_nextOp];
m_backtrackingState.linkTo(endOp.m_reentry, this);
break;
}
case OpParenthesesSubpatternTerminalEnd:
// We should never be backtracking to here (hence the 'terminal' in the name).
ASSERT(m_backtrackingState.isEmpty());
m_backtrackingState.append(op.m_jumps);
break;
// OpParentheticalAssertionBegin/End
case OpParentheticalAssertionBegin: {
PatternTerm* term = op.m_term;
YarrOp& endOp = m_ops[op.m_nextOp];
// We need to handle the backtracks upon backtracking back out
// of a parenthetical assertion if either we need to correct
// the input index, or the assertion was inverted.
if (op.m_checkAdjust || term->invert()) {
m_backtrackingState.link(this);
if (op.m_checkAdjust)
add32(Imm32(op.m_checkAdjust), index);
// In an inverted assertion failure to match the subpattern
// is treated as a successful match - jump to the end of the
// subpattern. We already have adjusted the input position
// back to that before the assertion, which is correct.
if (term->invert())
jump(endOp.m_reentry);
m_backtrackingState.fallthrough();
}
// The End node's jump list will contain any backtracks into
// the end of the assertion. Also, if inverted, we will have
// added the failure caused by a successful match to this.
m_backtrackingState.append(endOp.m_jumps);
m_checked += op.m_checkAdjust;
break;
}
case OpParentheticalAssertionEnd: {
// FIXME: We should really be clearing any nested subpattern
// matches on bailing out from after the pattern. Firefox has
// this bug too (presumably because they use YARR!)
// Never backtrack into an assertion; later failures bail to before the begin.
m_backtrackingState.takeBacktracksToJumpList(op.m_jumps, this);
YarrOp& lastOp = m_ops[op.m_previousOp];
m_checked -= lastOp.m_checkAdjust;
break;
}
case OpMatchFailed:
break;
}
} while (opIndex);
}
// Compilation methods:
// ====================
// opCompileParenthesesSubpattern
// Emits ops for a subpattern (set of parentheses). These consist
// of a set of alternatives wrapped in an outer set of nodes for
// the parentheses.
// Supported types of parentheses are 'Once' (quantityCount == 1)
// and 'Terminal' (non-capturing parentheses quantified as greedy
// and infinite).
// Alternatives will use the 'Simple' set of ops if either the
// subpattern is terminal (in which case we will never need to
// backtrack), or if the subpattern only contains one alternative.
void opCompileParenthesesSubpattern(PatternTerm* term)
{
YarrOpCode parenthesesBeginOpCode;
YarrOpCode parenthesesEndOpCode;
YarrOpCode alternativeBeginOpCode = OpSimpleNestedAlternativeBegin;
YarrOpCode alternativeNextOpCode = OpSimpleNestedAlternativeNext;
YarrOpCode alternativeEndOpCode = OpSimpleNestedAlternativeEnd;
// We can currently only compile quantity 1 subpatterns that are
// not copies. We generate a copy in the case of a range quantifier,
// e.g. /(?:x){3,9}/, or /(?:x)+/ (These are effectively expanded to
// /(?:x){3,3}(?:x){0,6}/ and /(?:x)(?:x)*/ repectively). The problem
// comes where the subpattern is capturing, in which case we would
// need to restore the capture from the first subpattern upon a
// failure in the second.
if (term->quantityCount == 1 && !term->parentheses.isCopy) {
// Select the 'Once' nodes.
parenthesesBeginOpCode = OpParenthesesSubpatternOnceBegin;
parenthesesEndOpCode = OpParenthesesSubpatternOnceEnd;
// If there is more than one alternative we cannot use the 'simple' nodes.
if (term->parentheses.disjunction->m_alternatives.size() != 1) {
alternativeBeginOpCode = OpNestedAlternativeBegin;
alternativeNextOpCode = OpNestedAlternativeNext;
alternativeEndOpCode = OpNestedAlternativeEnd;
}
} else if (term->parentheses.isTerminal) {
// Select the 'Terminal' nodes.
parenthesesBeginOpCode = OpParenthesesSubpatternTerminalBegin;
parenthesesEndOpCode = OpParenthesesSubpatternTerminalEnd;
} else {
// This subpattern is not supported by the JIT.
m_shouldFallBack = true;
return;
}
size_t parenBegin = m_ops.size();
m_ops.append(parenthesesBeginOpCode);
m_ops.append(alternativeBeginOpCode);
m_ops.last().m_previousOp = notFound;
m_ops.last().m_term = term;
Vector<PatternAlternative*>& alternatives = term->parentheses.disjunction->m_alternatives;
for (unsigned i = 0; i < alternatives.size(); ++i) {
size_t lastOpIndex = m_ops.size() - 1;
PatternAlternative* nestedAlternative = alternatives[i];
opCompileAlternative(nestedAlternative);
size_t thisOpIndex = m_ops.size();
m_ops.append(YarrOp(alternativeNextOpCode));
YarrOp& lastOp = m_ops[lastOpIndex];
YarrOp& thisOp = m_ops[thisOpIndex];
lastOp.m_alternative = nestedAlternative;
lastOp.m_nextOp = thisOpIndex;
thisOp.m_previousOp = lastOpIndex;
thisOp.m_term = term;
}
YarrOp& lastOp = m_ops.last();
ASSERT(lastOp.m_op == alternativeNextOpCode);
lastOp.m_op = alternativeEndOpCode;
lastOp.m_alternative = 0;
lastOp.m_nextOp = notFound;
size_t parenEnd = m_ops.size();
m_ops.append(parenthesesEndOpCode);
m_ops[parenBegin].m_term = term;
m_ops[parenBegin].m_previousOp = notFound;
m_ops[parenBegin].m_nextOp = parenEnd;
m_ops[parenEnd].m_term = term;
m_ops[parenEnd].m_previousOp = parenBegin;
m_ops[parenEnd].m_nextOp = notFound;
}
// opCompileParentheticalAssertion
// Emits ops for a parenthetical assertion. These consist of an
// OpSimpleNestedAlternativeBegin/Next/End set of nodes wrapping
// the alternatives, with these wrapped by an outer pair of
// OpParentheticalAssertionBegin/End nodes.
// We can always use the OpSimpleNestedAlternative nodes in the
// case of parenthetical assertions since these only ever match
// once, and will never backtrack back into the assertion.
void opCompileParentheticalAssertion(PatternTerm* term)
{
size_t parenBegin = m_ops.size();
m_ops.append(OpParentheticalAssertionBegin);
m_ops.append(OpSimpleNestedAlternativeBegin);
m_ops.last().m_previousOp = notFound;
m_ops.last().m_term = term;
Vector<PatternAlternative*>& alternatives = term->parentheses.disjunction->m_alternatives;
for (unsigned i = 0; i < alternatives.size(); ++i) {
size_t lastOpIndex = m_ops.size() - 1;
PatternAlternative* nestedAlternative = alternatives[i];
opCompileAlternative(nestedAlternative);
size_t thisOpIndex = m_ops.size();
m_ops.append(YarrOp(OpSimpleNestedAlternativeNext));
YarrOp& lastOp = m_ops[lastOpIndex];
YarrOp& thisOp = m_ops[thisOpIndex];
lastOp.m_alternative = nestedAlternative;
lastOp.m_nextOp = thisOpIndex;
thisOp.m_previousOp = lastOpIndex;
thisOp.m_term = term;
}
YarrOp& lastOp = m_ops.last();
ASSERT(lastOp.m_op == OpSimpleNestedAlternativeNext);
lastOp.m_op = OpSimpleNestedAlternativeEnd;
lastOp.m_alternative = 0;
lastOp.m_nextOp = notFound;
size_t parenEnd = m_ops.size();
m_ops.append(OpParentheticalAssertionEnd);
m_ops[parenBegin].m_term = term;
m_ops[parenBegin].m_previousOp = notFound;
m_ops[parenBegin].m_nextOp = parenEnd;
m_ops[parenEnd].m_term = term;
m_ops[parenEnd].m_previousOp = parenBegin;
m_ops[parenEnd].m_nextOp = notFound;
}
// opCompileAlternative
// Called to emit nodes for all terms in an alternative.
void opCompileAlternative(PatternAlternative* alternative)
{
optimizeAlternative(alternative);
for (unsigned i = 0; i < alternative->m_terms.size(); ++i) {
PatternTerm* term = &alternative->m_terms[i];
switch (term->type) {
case PatternTerm::TypeParenthesesSubpattern:
opCompileParenthesesSubpattern(term);
break;
case PatternTerm::TypeParentheticalAssertion:
opCompileParentheticalAssertion(term);
break;
default:
m_ops.append(term);
}
}
}
// opCompileBody
// This method compiles the body disjunction of the regular expression.
// The body consists of two sets of alternatives - zero or more 'once
// through' (BOL anchored) alternatives, followed by zero or more
// repeated alternatives.
// For each of these two sets of alteratives, if not empty they will be
// wrapped in a set of OpBodyAlternativeBegin/Next/End nodes (with the
// 'begin' node referencing the first alternative, and 'next' nodes
// referencing any further alternatives. The begin/next/end nodes are
// linked together in a doubly linked list. In the case of repeating
// alternatives, the end node is also linked back to the beginning.
// If no repeating alternatives exist, then a OpMatchFailed node exists
// to return the failing result.
void opCompileBody(PatternDisjunction* disjunction)
{
Vector<PatternAlternative*>& alternatives = disjunction->m_alternatives;
size_t currentAlternativeIndex = 0;
// Emit the 'once through' alternatives.
if (alternatives.size() && alternatives[0]->onceThrough()) {
m_ops.append(YarrOp(OpBodyAlternativeBegin));
m_ops.last().m_previousOp = notFound;
do {
size_t lastOpIndex = m_ops.size() - 1;
PatternAlternative* alternative = alternatives[currentAlternativeIndex];
opCompileAlternative(alternative);
size_t thisOpIndex = m_ops.size();
m_ops.append(YarrOp(OpBodyAlternativeNext));
YarrOp& lastOp = m_ops[lastOpIndex];
YarrOp& thisOp = m_ops[thisOpIndex];
lastOp.m_alternative = alternative;
lastOp.m_nextOp = thisOpIndex;
thisOp.m_previousOp = lastOpIndex;
++currentAlternativeIndex;
} while (currentAlternativeIndex < alternatives.size() && alternatives[currentAlternativeIndex]->onceThrough());
YarrOp& lastOp = m_ops.last();
ASSERT(lastOp.m_op == OpBodyAlternativeNext);
lastOp.m_op = OpBodyAlternativeEnd;
lastOp.m_alternative = 0;
lastOp.m_nextOp = notFound;
}
if (currentAlternativeIndex == alternatives.size()) {
m_ops.append(YarrOp(OpMatchFailed));
return;
}
// Emit the repeated alternatives.
size_t repeatLoop = m_ops.size();
m_ops.append(YarrOp(OpBodyAlternativeBegin));
m_ops.last().m_previousOp = notFound;
do {
size_t lastOpIndex = m_ops.size() - 1;
PatternAlternative* alternative = alternatives[currentAlternativeIndex];
ASSERT(!alternative->onceThrough());
opCompileAlternative(alternative);
size_t thisOpIndex = m_ops.size();
m_ops.append(YarrOp(OpBodyAlternativeNext));
YarrOp& lastOp = m_ops[lastOpIndex];
YarrOp& thisOp = m_ops[thisOpIndex];
lastOp.m_alternative = alternative;
lastOp.m_nextOp = thisOpIndex;
thisOp.m_previousOp = lastOpIndex;
++currentAlternativeIndex;
} while (currentAlternativeIndex < alternatives.size());
YarrOp& lastOp = m_ops.last();
ASSERT(lastOp.m_op == OpBodyAlternativeNext);
lastOp.m_op = OpBodyAlternativeEnd;
lastOp.m_alternative = 0;
lastOp.m_nextOp = repeatLoop;
}
void generateEnter()
{
#if CPU(X86_64)
push(X86Registers::ebp);
move(stackPointerRegister, X86Registers::ebp);
push(X86Registers::ebx);
#elif CPU(X86)
push(X86Registers::ebp);
move(stackPointerRegister, X86Registers::ebp);
// TODO: do we need spill registers to fill the output pointer if there are no sub captures?
push(X86Registers::ebx);
push(X86Registers::edi);
push(X86Registers::esi);
// load output into edi (2 = saved ebp + return address).
#if COMPILER(MSVC)
loadPtr(Address(X86Registers::ebp, 2 * sizeof(void*)), input);
loadPtr(Address(X86Registers::ebp, 3 * sizeof(void*)), index);
loadPtr(Address(X86Registers::ebp, 4 * sizeof(void*)), length);
if (compileMode == IncludeSubpatterns)
loadPtr(Address(X86Registers::ebp, 5 * sizeof(void*)), output);
#else
if (compileMode == IncludeSubpatterns)
loadPtr(Address(X86Registers::ebp, 2 * sizeof(void*)), output);
#endif
#elif CPU(ARM)
push(ARMRegisters::r4);
push(ARMRegisters::r5);
push(ARMRegisters::r6);
#if CPU(ARM_TRADITIONAL)
push(ARMRegisters::r8); // scratch register
#endif
if (compileMode == IncludeSubpatterns)
move(ARMRegisters::r3, output);
#elif CPU(SH4)
push(SH4Registers::r11);
push(SH4Registers::r13);
#elif CPU(MIPS)
// Do nothing.
#endif
}
void generateReturn()
{
#if CPU(X86_64)
pop(X86Registers::ebx);
pop(X86Registers::ebp);
#elif CPU(X86)
pop(X86Registers::esi);
pop(X86Registers::edi);
pop(X86Registers::ebx);
pop(X86Registers::ebp);
#elif CPU(ARM)
#if CPU(ARM_TRADITIONAL)
pop(ARMRegisters::r8); // scratch register
#endif
pop(ARMRegisters::r6);
pop(ARMRegisters::r5);
pop(ARMRegisters::r4);
#elif CPU(SH4)
pop(SH4Registers::r13);
pop(SH4Registers::r11);
#elif CPU(MIPS)
// Do nothing
#endif
ret();
}
public:
YarrGenerator(YarrPattern& pattern, YarrCharSize charSize)
: m_pattern(pattern)
, m_charSize(charSize)
, m_charScale(m_charSize == Char8 ? TimesOne: TimesTwo)
, m_shouldFallBack(false)
, m_checked(0)
{
}
void compile(JSGlobalData* globalData, YarrCodeBlock& jitObject)
{
generateEnter();
Jump hasInput = checkInput();
move(TrustedImmPtr((void*)WTF::notFound), returnRegister);
move(TrustedImm32(0), returnRegister2);
generateReturn();
hasInput.link(this);
if (compileMode == IncludeSubpatterns) {
for (unsigned i = 0; i < m_pattern.m_numSubpatterns + 1; ++i)
store32(TrustedImm32(-1), Address(output, (i << 1) * sizeof(int)));
}
if (!m_pattern.m_body->m_hasFixedSize)
setMatchStart(index);
initCallFrame();
// Compile the pattern to the internal 'YarrOp' representation.
opCompileBody(m_pattern.m_body);
// If we encountered anything we can't handle in the JIT code
// (e.g. backreferences) then return early.
if (m_shouldFallBack) {
jitObject.setFallBack(true);
return;
}
generate();
backtrack();
// Link & finalize the code.
LinkBuffer linkBuffer(*globalData, this, REGEXP_CODE_ID);
m_backtrackingState.linkDataLabels(linkBuffer);
if (compileMode == MatchOnly) {
if (m_charSize == Char8)
jitObject.set8BitCodeMatchOnly(FINALIZE_CODE(linkBuffer, ("Match-only 8-bit regular expression")));
else
jitObject.set16BitCodeMatchOnly(FINALIZE_CODE(linkBuffer, ("Match-only 16-bit regular expression")));
} else {
if (m_charSize == Char8)
jitObject.set8BitCode(FINALIZE_CODE(linkBuffer, ("8-bit regular expression")));
else
jitObject.set16BitCode(FINALIZE_CODE(linkBuffer, ("16-bit regular expression")));
}
jitObject.setFallBack(m_shouldFallBack);
}
private:
YarrPattern& m_pattern;
YarrCharSize m_charSize;
Scale m_charScale;
// Used to detect regular expression constructs that are not currently
// supported in the JIT; fall back to the interpreter when this is detected.
bool m_shouldFallBack;
// The regular expression expressed as a linear sequence of operations.
Vector<YarrOp, 128> m_ops;
// This records the current input offset being applied due to the current
// set of alternatives we are nested within. E.g. when matching the
// character 'b' within the regular expression /abc/, we will know that
// the minimum size for the alternative is 3, checked upon entry to the
// alternative, and that 'b' is at offset 1 from the start, and as such
// when matching 'b' we need to apply an offset of -2 to the load.
//
// FIXME: This should go away. Rather than tracking this value throughout
// code generation, we should gather this information up front & store it
// on the YarrOp structure.
int m_checked;
// This class records state whilst generating the backtracking path of code.
BacktrackingState m_backtrackingState;
};
void jitCompile(YarrPattern& pattern, YarrCharSize charSize, JSGlobalData* globalData, YarrCodeBlock& jitObject, YarrJITCompileMode mode)
{
if (mode == MatchOnly)
YarrGenerator<MatchOnly>(pattern, charSize).compile(globalData, jitObject);
else
YarrGenerator<IncludeSubpatterns>(pattern, charSize).compile(globalData, jitObject);
}
}}
#endif