diff options
Diffstat (limited to 'src/3rdparty/webkit/Source/JavaScriptCore/yarr/YarrJIT.cpp')
| -rw-r--r-- | src/3rdparty/webkit/Source/JavaScriptCore/yarr/YarrJIT.cpp | 3098 |
1 files changed, 1609 insertions, 1489 deletions
diff --git a/src/3rdparty/webkit/Source/JavaScriptCore/yarr/YarrJIT.cpp b/src/3rdparty/webkit/Source/JavaScriptCore/yarr/YarrJIT.cpp index ece2379..f3356b1 100644 --- a/src/3rdparty/webkit/Source/JavaScriptCore/yarr/YarrJIT.cpp +++ b/src/3rdparty/webkit/Source/JavaScriptCore/yarr/YarrJIT.cpp @@ -228,9 +228,10 @@ class YarrGenerator : private MacroAssembler { } // Jumps if input not available; will have (incorrectly) incremented already! - Jump jumpIfNoAvailableInput(unsigned countToCheck) + Jump jumpIfNoAvailableInput(unsigned countToCheck = 0) { - add32(Imm32(countToCheck), index); + if (countToCheck) + add32(Imm32(countToCheck), index); return branch32(Above, index, length); } @@ -295,1056 +296,455 @@ class YarrGenerator : private MacroAssembler { jump(Address(stackPointerRegister, frameLocation * sizeof(void*))); } - struct IndirectJumpEntry { - IndirectJumpEntry(int32_t stackOffset) - : m_stackOffset(stackOffset) - { - } - - IndirectJumpEntry(int32_t stackOffset, Jump jump) - : m_stackOffset(stackOffset) - { - addJump(jump); - } - - IndirectJumpEntry(int32_t stackOffset, DataLabelPtr dataLabel) - : m_stackOffset(stackOffset) - { - addDataLabel(dataLabel); - } - - void addJump(Jump jump) - { - m_relJumps.append(jump); - } - - void addDataLabel(DataLabelPtr dataLabel) - { - m_dataLabelPtrVector.append(dataLabel); - } - - int32_t m_stackOffset; - JumpList m_relJumps; - Vector<DataLabelPtr, 16> m_dataLabelPtrVector; + 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 }; - struct AlternativeBacktrackRecord { - DataLabelPtr dataLabel; - Label backtrackLocation; - - AlternativeBacktrackRecord(DataLabelPtr dataLabel, Label backtrackLocation) - : dataLabel(dataLabel) - , backtrackLocation(backtrackLocation) - { - } - }; - - struct ParenthesesTail; - struct TermGenerationState; - - struct GenerationState { - typedef HashMap<int, IndirectJumpEntry*, WTF::IntHash<uint32_t>, UnsignedWithZeroKeyHashTraits<uint32_t> > IndirectJumpHashMap; - - GenerationState() - : m_parenNestingLevel(0) - { - } - - void addIndirectJumpEntry(int32_t stackOffset, Jump jump) - { - IndirectJumpHashMap::iterator result = m_indirectJumpMap.find(stackOffset); - - ASSERT(stackOffset >= 0); - - uint32_t offset = static_cast<uint32_t>(stackOffset); - - if (result == m_indirectJumpMap.end()) - m_indirectJumpMap.add(offset, new IndirectJumpEntry(stackOffset, jump)); - else - result->second->addJump(jump); - } - - void addIndirectJumpEntry(int32_t stackOffset, JumpList jumps) - { - JumpList::JumpVector jumpVector = jumps.jumps(); - size_t size = jumpVector.size(); - for (size_t i = 0; i < size; ++i) - addIndirectJumpEntry(stackOffset, jumpVector[i]); - - jumps.empty(); - } - - void addIndirectJumpEntry(int32_t stackOffset, DataLabelPtr dataLabel) - { - IndirectJumpHashMap::iterator result = m_indirectJumpMap.find(stackOffset); - - ASSERT(stackOffset >= 0); - - uint32_t offset = static_cast<uint32_t>(stackOffset); - - if (result == m_indirectJumpMap.end()) - m_indirectJumpMap.add(offset, new IndirectJumpEntry(stackOffset, dataLabel)); - else - result->second->addDataLabel(dataLabel); - } - - void emitIndirectJumpTable(MacroAssembler* masm) + // 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) { - for (IndirectJumpHashMap::iterator iter = m_indirectJumpMap.begin(); iter != m_indirectJumpMap.end(); ++iter) { - IndirectJumpEntry* indJumpEntry = iter->second; - size_t size = indJumpEntry->m_dataLabelPtrVector.size(); - if (size) { - // Link any associated DataLabelPtr's with indirect jump via label - Label hereLabel = masm->label(); - for (size_t i = 0; i < size; ++i) - m_backtrackRecords.append(AlternativeBacktrackRecord(indJumpEntry->m_dataLabelPtrVector[i], hereLabel)); - } - indJumpEntry->m_relJumps.link(masm); - masm->jump(Address(stackPointerRegister, indJumpEntry->m_stackOffset)); - delete indJumpEntry; - } - } - - void incrementParenNestingLevel() - { - ++m_parenNestingLevel; - } - - void decrementParenNestingLevel() - { - --m_parenNestingLevel; - } - - ParenthesesTail* addParenthesesTail(PatternTerm& term, JumpList* jumpListToPriorParen) - { - OwnPtr<ParenthesesTail> tail = adoptPtr(new ParenthesesTail(term, m_parenNestingLevel, jumpListToPriorParen)); - ParenthesesTail* rawTail = tail.get(); - - m_parenTails.append(tail.release()); - m_parenTailsForIteration.append(rawTail); - - return rawTail; } - void emitParenthesesTail(YarrGenerator* generator) + explicit YarrOp(YarrOpCode op) + : m_op(op) + , m_isDeadCode(false) { - unsigned vectorSize = m_parenTails.size(); - bool priorBacktrackFallThrough = false; - - // Emit in reverse order so parentTail N can fall through to N-1 - for (unsigned index = vectorSize; index > 0; --index) { - JumpList jumpsToNext; - priorBacktrackFallThrough = m_parenTails[index-1].get()->generateCode(generator, jumpsToNext, priorBacktrackFallThrough, index > 1); - if (index > 1) - jumpsToNext.linkTo(generator->label(), generator); - else - addJumpsToNextInteration(jumpsToNext); - } - m_parenTails.clear(); } - void addJumpToNextInteration(Jump jump) - { - m_jumpsToNextInteration.append(jump); - } + // The operation, as a YarrOpCode, and also a reference to the PatternTerm. + YarrOpCode m_op; + PatternTerm* m_term; - void addJumpsToNextInteration(JumpList jumps) - { - m_jumpsToNextInteration.append(jumps); - } + // 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; - void addDataLabelToNextIteration(DataLabelPtr dataLabel) - { - m_dataPtrsToNextIteration.append(dataLabel); - } + // 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; - void linkToNextIteration(Label label) - { - m_nextIteration = label; + // This flag is used to null out the second pattern character, when + // two are fused to match a pair together. + bool m_isDeadCode; - for (unsigned i = 0; i < m_dataPtrsToNextIteration.size(); ++i) - m_backtrackRecords.append(AlternativeBacktrackRecord(m_dataPtrsToNextIteration[i], m_nextIteration)); + // 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; - m_dataPtrsToNextIteration.clear(); - - for (unsigned i = 0; i < m_parenTailsForIteration.size(); ++i) - m_parenTailsForIteration[i]->setNextIteration(m_nextIteration); - - m_parenTailsForIteration.clear(); - } - - void linkToNextIteration(YarrGenerator* generator) - { - m_jumpsToNextInteration.linkTo(m_nextIteration, generator); - } - - int m_parenNestingLevel; - Vector<AlternativeBacktrackRecord> m_backtrackRecords; - IndirectJumpHashMap m_indirectJumpMap; - Label m_nextIteration; - Vector<OwnPtr<ParenthesesTail> > m_parenTails; - JumpList m_jumpsToNextInteration; - Vector<DataLabelPtr> m_dataPtrsToNextIteration; - Vector<ParenthesesTail*> m_parenTailsForIteration; + // 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; }; - struct BacktrackDestination { - typedef enum { - NoBacktrack, - BacktrackLabel, - BacktrackStackOffset, - BacktrackJumpList, - BacktrackLinked - } BacktrackType; - - BacktrackDestination() - : m_backtrackType(NoBacktrack) - , m_backtrackToLabel(0) - , m_subDataLabelPtr(0) - , m_nextBacktrack(0) - , m_backtrackSourceLabel(0) - , m_backtrackSourceJumps(0) + // 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) { } - BacktrackDestination(int32_t stackOffset) - : m_backtrackType(BacktrackStackOffset) - , m_backtrackStackOffset(stackOffset) - , m_backtrackToLabel(0) - , m_subDataLabelPtr(0) - , m_nextBacktrack(0) - , m_backtrackSourceLabel(0) - , m_backtrackSourceJumps(0) + // 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); } - - BacktrackDestination(Label label) - : m_backtrackType(BacktrackLabel) - , m_backtrackLabel(label) - , m_backtrackToLabel(0) - , m_subDataLabelPtr(0) - , m_nextBacktrack(0) - , m_backtrackSourceLabel(0) - , m_backtrackSourceJumps(0) + void append(JumpList& jumpList) { + m_laterFailures.append(jumpList); } - - void clear(bool doDataLabelClear = true) + void append(const DataLabelPtr& returnAddress) { - m_backtrackType = NoBacktrack; - if (doDataLabelClear) - clearDataLabel(); - m_nextBacktrack = 0; + m_pendingReturns.append(returnAddress); } - - void clearDataLabel() + void fallthrough() { - m_dataLabelPtr = DataLabelPtr(); + ASSERT(!m_pendingFallthrough); + m_pendingFallthrough = true; } - bool hasDestination() + // 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) { - return (m_backtrackType != NoBacktrack); - } - - bool isStackOffset() - { - return (m_backtrackType == BacktrackStackOffset); - } - - bool isLabel() - { - return (m_backtrackType == BacktrackLabel); - } - - bool isJumpList() - { - return (m_backtrackType == BacktrackJumpList); - } - - bool hasDataLabel() - { - return m_dataLabelPtr.isSet(); - } - - void copyTarget(BacktrackDestination& rhs, bool copyDataLabel = true) - { - m_backtrackType = rhs.m_backtrackType; - if (m_backtrackType == BacktrackStackOffset) - m_backtrackStackOffset = rhs.m_backtrackStackOffset; - else if (m_backtrackType == BacktrackLabel) - m_backtrackLabel = rhs.m_backtrackLabel; - if (copyDataLabel) - m_dataLabelPtr = rhs.m_dataLabelPtr; - m_backtrackSourceJumps = rhs.m_backtrackSourceJumps; - m_backtrackSourceLabel = rhs.m_backtrackSourceLabel; - } - - void copyTo(BacktrackDestination& lhs) - { - lhs.m_backtrackType = m_backtrackType; - if (m_backtrackType == BacktrackStackOffset) - lhs.m_backtrackStackOffset = m_backtrackStackOffset; - else if (m_backtrackType == BacktrackLabel) - lhs.m_backtrackLabel = m_backtrackLabel; - lhs.m_backtrackSourceJumps = m_backtrackSourceJumps; - lhs.m_backtrackSourceLabel = m_backtrackSourceLabel; - lhs.m_dataLabelPtr = m_dataLabelPtr; - lhs.m_backTrackJumps = m_backTrackJumps; - } - - void addBacktrackJump(Jump jump) - { - m_backTrackJumps.append(jump); - } - - void setStackOffset(int32_t stackOffset) - { - m_backtrackType = BacktrackStackOffset; - m_backtrackStackOffset = stackOffset; - } - - void setLabel(Label label) - { - m_backtrackType = BacktrackLabel; - m_backtrackLabel = label; - } - - void setNextBacktrackLabel(Label label) - { - if (m_nextBacktrack) - m_nextBacktrack->setLabel(label); - } - - void propagateBacktrackToLabel(const BacktrackDestination& rhs) - { - if (!m_backtrackToLabel && rhs.m_backtrackToLabel) - m_backtrackToLabel = rhs.m_backtrackToLabel; - } - - void setBacktrackToLabel(Label* backtrackToLabel) - { - if (!m_backtrackToLabel) - m_backtrackToLabel = backtrackToLabel; - } - - bool hasBacktrackToLabel() - { - return m_backtrackToLabel; - } - - void setBacktrackJumpList(JumpList* jumpList) - { - m_backtrackType = BacktrackJumpList; - m_backtrackSourceJumps = jumpList; - } - - void setBacktrackSourceLabel(Label* backtrackSourceLabel) - { - m_backtrackSourceLabel = backtrackSourceLabel; - } - - void setDataLabel(DataLabelPtr dp) - { - if (m_subDataLabelPtr) { - *m_subDataLabelPtr = dp; - m_subDataLabelPtr = 0; - } else { - ASSERT(!hasDataLabel()); - m_dataLabelPtr = dp; + 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 clearSubDataLabelPtr() - { - m_subDataLabelPtr = 0; - } - - void setSubDataLabelPtr(DataLabelPtr* subDataLabelPtr) + void linkTo(Label label, MacroAssembler* assembler) { - m_subDataLabelPtr = subDataLabelPtr; - } - - void linkToNextBacktrack(BacktrackDestination* nextBacktrack) - { - m_nextBacktrack = nextBacktrack; - } - - int32_t getStackOffset() - { - ASSERT(m_backtrackType == BacktrackStackOffset); - return m_backtrackStackOffset; - } - - Label getLabel() - { - ASSERT(m_backtrackType == BacktrackLabel); - return m_backtrackLabel; - } - - JumpList& getBacktrackJumps() - { - return m_backTrackJumps; - } - - DataLabelPtr& getDataLabel() - { - return m_dataLabelPtr; - } - - void jumpToBacktrack(MacroAssembler* masm) - { - if (isJumpList()) { - if (m_backtrackSourceLabel && (m_backtrackSourceLabel->isSet())) - masm->jump().linkTo(*m_backtrackSourceLabel, masm); - else - m_backtrackSourceJumps->append(masm->jump()); - } else if (isStackOffset()) - masm->jump(Address(stackPointerRegister, m_backtrackStackOffset)); - else if (isLabel()) - masm->jump().linkTo(m_backtrackLabel, masm); - else - m_backTrackJumps.append(masm->jump()); - } - - void jumpToBacktrack(YarrGenerator* generator, Jump jump) - { - if (isJumpList()) { - if (m_backtrackSourceLabel && (m_backtrackSourceLabel->isSet())) - jump.linkTo(*m_backtrackSourceLabel, generator); - else - m_backtrackSourceJumps->append(jump); - } else if (isStackOffset()) - generator->m_expressionState.addIndirectJumpEntry(getStackOffset(), jump); - else if (isLabel()) - jump.linkTo(getLabel(), generator); - else - m_backTrackJumps.append(jump); - } - - void jumpToBacktrack(YarrGenerator* generator, JumpList& jumps) - { - if (isJumpList()) { - if (m_backtrackSourceLabel && (m_backtrackSourceLabel->isSet())) - jumps.linkTo(*m_backtrackSourceLabel, generator); - else - m_backtrackSourceJumps->append(jumps); - } else if (isStackOffset()) - generator->m_expressionState.addIndirectJumpEntry(getStackOffset(), jumps); - else if (isLabel()) - jumps.linkTo(getLabel(), generator); - else - m_backTrackJumps.append(jumps); - } - - bool plantJumpToBacktrackIfExists(YarrGenerator* generator) - { - if (isJumpList()) { - if (m_backtrackSourceLabel && (m_backtrackSourceLabel->isSet())) - generator->jump(*m_backtrackSourceLabel); - else - m_backtrackSourceJumps->append(generator->jump()); - - return true; - } - - if (isStackOffset()) { - generator->jump(Address(stackPointerRegister, getStackOffset())); - return true; + 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 (isLabel()) { - generator->jump(getLabel()); - if (hasDataLabel()) { - generator->m_expressionState.m_backtrackRecords.append(AlternativeBacktrackRecord(getDataLabel(), getLabel())); - clearDataLabel(); - } - return true; + 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; } - - return false; + if (m_pendingFallthrough) + jumpList.append(assembler->jump()); + jumpList.append(m_laterFailures); + m_laterFailures.clear(); + m_pendingFallthrough = false; } - void linkBacktrackToLabel(Label backtrackLabel) + bool isEmpty() { - if (m_backtrackToLabel) - *m_backtrackToLabel = backtrackLabel; + return m_laterFailures.empty() && m_pendingReturns.isEmpty() && !m_pendingFallthrough; } - void linkAlternativeBacktracks(YarrGenerator* generator, bool nextIteration = false) + // Called at the end of code generation to link all return addresses. + void linkDataLabels(LinkBuffer& linkBuffer) { - Label hereLabel = generator->label(); - - if (m_backtrackToLabel) { - *m_backtrackToLabel = hereLabel; - m_backtrackToLabel = 0; - } - - m_backTrackJumps.link(generator); - - if (nextIteration) - generator->m_expressionState.linkToNextIteration(hereLabel); - - if (hasDataLabel()) { - generator->m_expressionState.m_backtrackRecords.append(AlternativeBacktrackRecord(getDataLabel(), hereLabel)); - // data label cleared as a result of the clear() below - } - - clear(); - } - - void linkAlternativeBacktracksTo(YarrGenerator* generator, Label label, bool nextIteration = false) - { - m_backTrackJumps.linkTo(label, generator); - - if (nextIteration) - generator->m_expressionState.linkToNextIteration(label); - - if (hasDataLabel()) { - generator->m_expressionState.m_backtrackRecords.append(AlternativeBacktrackRecord(getDataLabel(), label)); - clearDataLabel(); - } + 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: - BacktrackType m_backtrackType; - int32_t m_backtrackStackOffset; - Label m_backtrackLabel; - DataLabelPtr m_dataLabelPtr; - Label* m_backtrackToLabel; - DataLabelPtr* m_subDataLabelPtr; - BacktrackDestination* m_nextBacktrack; - Label* m_backtrackSourceLabel; - JumpList* m_backtrackSourceJumps; - JumpList m_backTrackJumps; - }; - - struct TermGenerationState { - TermGenerationState(PatternDisjunction* disjunction, unsigned checkedTotal) - : disjunction(disjunction) - , checkedTotal(checkedTotal) - , m_subParenNum(0) - , m_linkedBacktrack(0) - , m_jumpList(0) - { - } - - void resetAlternative() - { - m_backtrack.clear(); - alt = 0; - } - bool alternativeValid() - { - return alt < disjunction->m_alternatives.size(); - } - void nextAlternative() - { - ++alt; - } - PatternAlternative* alternative() - { - return disjunction->m_alternatives[alt]; - } - bool isLastAlternative() - { - return (alt + 1) == disjunction->m_alternatives.size(); - } - - void resetTerm() - { - ASSERT(alternativeValid()); - t = 0; - m_subParenNum = 0; - } - bool termValid() - { - ASSERT(alternativeValid()); - return t < alternative()->m_terms.size(); - } - void nextTerm() - { - ASSERT(alternativeValid()); - ++t; - } - PatternTerm& term() - { - ASSERT(alternativeValid()); - return alternative()->m_terms[t]; - } - bool isLastTerm() - { - ASSERT(alternativeValid()); - return (t + 1) == alternative()->m_terms.size(); - } - unsigned getSubParenNum() - { - return m_subParenNum++; - } - bool isMainDisjunction() - { - return !disjunction->m_parent; - } - - void setJumpListToPriorParen(JumpList* jumpList) - { - m_jumpList = jumpList; - } - - JumpList* getJumpListToPriorParen() - { - return m_jumpList; - } - - PatternTerm& lookaheadTerm() - { - ASSERT(alternativeValid()); - ASSERT((t + 1) < alternative()->m_terms.size()); - return alternative()->m_terms[t + 1]; - } - bool isSinglePatternCharacterLookaheadTerm() - { - ASSERT(alternativeValid()); - return ((t + 1) < alternative()->m_terms.size()) - && (lookaheadTerm().type == PatternTerm::TypePatternCharacter) - && (lookaheadTerm().quantityType == QuantifierFixedCount) - && (lookaheadTerm().quantityCount == 1); - } - - int inputOffset() - { - return term().inputPosition - checkedTotal; - } - - void clearBacktrack() - { - m_backtrack.clear(false); - m_linkedBacktrack = 0; - } - - void jumpToBacktrack(MacroAssembler* masm) - { - m_backtrack.jumpToBacktrack(masm); - } - - void jumpToBacktrack(YarrGenerator* generator, Jump jump) - { - m_backtrack.jumpToBacktrack(generator, jump); - } - - void jumpToBacktrack(YarrGenerator* generator, JumpList& jumps) - { - m_backtrack.jumpToBacktrack(generator, jumps); - } - - bool plantJumpToBacktrackIfExists(YarrGenerator* generator) - { - return m_backtrack.plantJumpToBacktrackIfExists(generator); - } - - void linkDataLabelToBacktrackIfExists(YarrGenerator* generator, DataLabelPtr dataLabel) - { - // If we have a stack offset backtrack destination, use it directly - if (m_backtrack.isStackOffset()) { - generator->m_expressionState.addIndirectJumpEntry(m_backtrack.getStackOffset(), dataLabel); - m_backtrack.clearSubDataLabelPtr(); - } else { - // If we have a backtrack label, connect the datalabel to it directly. - if (m_backtrack.isLabel()) { - generator->m_expressionState.m_backtrackRecords.append(AlternativeBacktrackRecord(dataLabel, m_backtrack.getLabel())); - m_backtrack.clearSubDataLabelPtr(); - } else - setBacktrackDataLabel(dataLabel); + struct ReturnAddressRecord { + ReturnAddressRecord(DataLabelPtr dataLabel, Label backtrackLocation) + : m_dataLabel(dataLabel) + , m_backtrackLocation(backtrackLocation) + { } - } - - void addBacktrackJump(Jump jump) - { - m_backtrack.addBacktrackJump(jump); - } - - void setBacktrackDataLabel(DataLabelPtr dp) - { - m_backtrack.setDataLabel(dp); - } - - void setBackTrackStackOffset(int32_t stackOffset) - { - m_backtrack.setStackOffset(stackOffset); - } - - void setBacktrackLabel(Label label) - { - m_backtrack.setLabel(label); - } - - void linkAlternativeBacktracks(YarrGenerator* generator, bool nextIteration = false) - { - m_backtrack.linkAlternativeBacktracks(generator, nextIteration); - m_linkedBacktrack = 0; - } - - void linkAlternativeBacktracksTo(YarrGenerator* generator, Label label, bool nextIteration = false) - { - m_backtrack.linkAlternativeBacktracksTo(generator, label, nextIteration); - } - - void setBacktrackLink(BacktrackDestination* linkedBacktrack) - { - m_linkedBacktrack = linkedBacktrack; - } - - void chainBacktracks(BacktrackDestination* followonBacktrack) - { - if (m_linkedBacktrack) - m_linkedBacktrack->linkToNextBacktrack(followonBacktrack); - } - BacktrackDestination& getBacktrackDestination() - { - return m_backtrack; - } - - void propagateBacktrackingFrom(YarrGenerator* generator, BacktrackDestination& backtrack, bool doJump = true) - { - if (doJump) - m_backtrack.jumpToBacktrack(generator, backtrack.getBacktrackJumps()); - - if (m_backtrack.isLabel() && backtrack.hasBacktrackToLabel()) - backtrack.linkBacktrackToLabel(m_backtrack.getLabel()); - - if (backtrack.hasDestination()) { - if (m_backtrack.hasDataLabel()) - generator->m_expressionState.addDataLabelToNextIteration(m_backtrack.getDataLabel()); + DataLabelPtr m_dataLabel; + Label m_backtrackLocation; + }; - m_backtrack.copyTarget(backtrack, doJump); - } - } - - PatternDisjunction* disjunction; - int checkedTotal; - private: - unsigned alt; - unsigned t; - unsigned m_subParenNum; - BacktrackDestination m_backtrack; - BacktrackDestination* m_linkedBacktrack; - JumpList* m_jumpList; + JumpList m_laterFailures; + bool m_pendingFallthrough; + Vector<DataLabelPtr, 4> m_pendingReturns; + Vector<ReturnAddressRecord, 4> m_backtrackRecords; }; - struct ParenthesesTail { - ParenthesesTail(PatternTerm& term, int nestingLevel, JumpList* jumpListToPriorParen) - : m_term(term) - , m_nestingLevel(nestingLevel) - , m_subParenIndex(0) - , m_jumpListToPriorParen(jumpListToPriorParen) - { - } - - void processBacktracks(YarrGenerator* generator, TermGenerationState& state, TermGenerationState& parenthesesState, Label nonGreedyTryParentheses, Label fallThrough) - { - m_nonGreedyTryParentheses = nonGreedyTryParentheses; - m_fallThrough = fallThrough; - - m_subParenIndex = state.getSubParenNum(); - parenthesesState.getBacktrackDestination().copyTo(m_parenBacktrack); - state.chainBacktracks(&m_backtrack); - BacktrackDestination& stateBacktrack = state.getBacktrackDestination(); - stateBacktrack.copyTo(m_backtrack); - stateBacktrack.setBacktrackToLabel(&m_backtrackToLabel); - state.setBacktrackLink(&m_backtrack); - stateBacktrack.setSubDataLabelPtr(&m_dataAfterLabelPtr); - - m_doDirectBacktrack = m_parenBacktrack.hasDestination(); - - if ((m_term.quantityType == QuantifierGreedy) || (m_term.quantityType == QuantifierNonGreedy)) - m_doDirectBacktrack = false; - - if (m_doDirectBacktrack) - state.propagateBacktrackingFrom(generator, m_parenBacktrack, false); - else { - stateBacktrack.setBacktrackJumpList(&m_afterBacktrackJumps); - stateBacktrack.setBacktrackSourceLabel(&m_backtrackFromAfterParens); - } - } - - void setNextIteration(Label nextIteration) - { - if (!m_nestingLevel && !m_backtrackToLabel.isSet()) - m_backtrackToLabel = nextIteration; - } - - void addAfterParenJump(Jump jump) - { - m_afterBacktrackJumps.append(jump); - } + // Generation methods: + // =================== - bool generateCode(YarrGenerator* generator, JumpList& jumpsToNext, bool priorBackTrackFallThrough, bool nextBacktrackFallThrough) - { - const RegisterID indexTemporary = regT0; - unsigned parenthesesFrameLocation = m_term.frameLocation; - Jump fromPriorBacktrack; - bool needJumpForPriorParenTail = false; - - if (priorBackTrackFallThrough - && ((m_term.quantityType == QuantifierGreedy) - || (m_term.quantityType == QuantifierNonGreedy) - || (!m_doDirectBacktrack && m_parenBacktrack.hasDestination()))) { - // If the prior paren tail code assumed that it could fall through, - // but we need to generate after paren backtrack code, then provide - // a jump around that code for the prior paren tail code. - // A regular expressing like ((xxx)...)? needs this. - fromPriorBacktrack = generator->jump(); - needJumpForPriorParenTail = true; - } - - if (!m_backtrack.hasDestination()) { - if (m_backtrackToLabel.isSet()) { - m_backtrack.setLabel(m_backtrackToLabel); - nextBacktrackFallThrough = false; - } else if (m_jumpListToPriorParen) { - // If we don't have a destination, go back to either the prior paren or the next outer paren. - m_backtrack.setBacktrackJumpList(m_jumpListToPriorParen); - nextBacktrackFallThrough = false; - } else - m_backtrack.setBacktrackJumpList(&jumpsToNext); - } else - nextBacktrackFallThrough = false; - - // A failure AFTER the parens jumps here - Backtrack to this paren - m_backtrackFromAfterParens = generator->label(); - - if (m_dataAfterLabelPtr.isSet()) - generator->m_expressionState.m_backtrackRecords.append(AlternativeBacktrackRecord(m_dataAfterLabelPtr, m_backtrackFromAfterParens)); - - m_afterBacktrackJumps.link(generator); - - if (m_term.quantityType == QuantifierGreedy) { - // If this is -1 we have now tested with both with and without the parens. - generator->loadFromFrame(parenthesesFrameLocation, indexTemporary); - m_backtrack.jumpToBacktrack(generator, generator->branch32(Equal, indexTemporary, TrustedImm32(-1))); - } else if (m_term.quantityType == QuantifierNonGreedy) { - // If this is -1 we have now tested with both with and without the parens. - generator->loadFromFrame(parenthesesFrameLocation, indexTemporary); - generator->branch32(Equal, indexTemporary, TrustedImm32(-1)).linkTo(m_nonGreedyTryParentheses, generator); - } - - if (!m_doDirectBacktrack) - m_parenBacktrack.plantJumpToBacktrackIfExists(generator); - - // A failure WITHIN the parens jumps here - if (needJumpForPriorParenTail) - fromPriorBacktrack.link(generator); - m_parenBacktrack.linkAlternativeBacktracks(generator); - m_withinBacktrackJumps.link(generator); - - if (m_term.capture()) - generator->store32(TrustedImm32(-1), Address(output, (m_term.parentheses.subpatternId << 1) * sizeof(int))); - - if (m_term.quantityType == QuantifierGreedy) { - generator->storeToFrame(TrustedImm32(-1), parenthesesFrameLocation); - generator->jump().linkTo(m_fallThrough, generator); - nextBacktrackFallThrough = false; - } else if (!nextBacktrackFallThrough) - m_backtrack.jumpToBacktrack(generator); - - if (!m_doDirectBacktrack) - m_backtrack.setNextBacktrackLabel(m_backtrackFromAfterParens); - - return nextBacktrackFallThrough; - } - - PatternTerm& m_term; - int m_nestingLevel; - unsigned m_subParenIndex; - JumpList* m_jumpListToPriorParen; - Label m_nonGreedyTryParentheses; - Label m_fallThrough; - Label m_backtrackToLabel; - Label m_backtrackFromAfterParens; - DataLabelPtr m_dataAfterLabelPtr; - JumpList m_withinBacktrackJumps; - JumpList m_afterBacktrackJumps; - BacktrackDestination m_parenBacktrack; - BacktrackDestination m_backtrack; - bool m_doDirectBacktrack; - }; + // 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(TermGenerationState& state) + void generateAssertionBOL(size_t opIndex) { - PatternTerm& term = state.term(); + 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(state.checkedTotal))); + if (!term->inputPosition) + matchDest.append(branch32(Equal, index, Imm32(m_checked))); - readCharacter(state.inputOffset() - 1, character); + readCharacter((term->inputPosition - m_checked) - 1, character); matchCharacterClass(character, matchDest, m_pattern.newlineCharacterClass()); - state.jumpToBacktrack(this); + op.m_jumps.append(jump()); matchDest.link(this); } else { // Erk, really should poison out these alternatives early. :-/ - if (term.inputPosition) - state.jumpToBacktrack(this); + if (term->inputPosition) + op.m_jumps.append(jump()); else - state.jumpToBacktrack(this, branch32(NotEqual, index, Imm32(state.checkedTotal))); + op.m_jumps.append(branch32(NotEqual, index, Imm32(m_checked))); } } + void backtrackAssertionBOL(size_t opIndex) + { + backtrackTermDefault(opIndex); + } - void generateAssertionEOL(TermGenerationState& state) + void generateAssertionEOL(size_t opIndex) { - PatternTerm& term = state.term(); + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; if (m_pattern.m_multiline) { const RegisterID character = regT0; JumpList matchDest; - if (term.inputPosition == state.checkedTotal) + if (term->inputPosition == m_checked) matchDest.append(atEndOfInput()); - readCharacter(state.inputOffset(), character); + readCharacter((term->inputPosition - m_checked), character); matchCharacterClass(character, matchDest, m_pattern.newlineCharacterClass()); - state.jumpToBacktrack(this); + op.m_jumps.append(jump()); matchDest.link(this); } else { - if (term.inputPosition == state.checkedTotal) - state.jumpToBacktrack(this, notAtEndOfInput()); + if (term->inputPosition == m_checked) + op.m_jumps.append(notAtEndOfInput()); // Erk, really should poison out these alternatives early. :-/ else - state.jumpToBacktrack(this); + op.m_jumps.append(jump()); } } + void backtrackAssertionEOL(size_t opIndex) + { + backtrackTermDefault(opIndex); + } // Also falls though on nextIsNotWordChar. - void matchAssertionWordchar(TermGenerationState& state, JumpList& nextIsWordChar, JumpList& nextIsNotWordChar) + void matchAssertionWordchar(size_t opIndex, JumpList& nextIsWordChar, JumpList& nextIsNotWordChar) { + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + const RegisterID character = regT0; - PatternTerm& term = state.term(); - if (term.inputPosition == state.checkedTotal) + if (term->inputPosition == m_checked) nextIsNotWordChar.append(atEndOfInput()); - readCharacter(state.inputOffset(), character); + readCharacter((term->inputPosition - m_checked), character); matchCharacterClass(character, nextIsWordChar, m_pattern.wordcharCharacterClass()); } - void generateAssertionWordBoundary(TermGenerationState& state) + void generateAssertionWordBoundary(size_t opIndex) { + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + const RegisterID character = regT0; - PatternTerm& term = state.term(); Jump atBegin; JumpList matchDest; - if (!term.inputPosition) - atBegin = branch32(Equal, index, Imm32(state.checkedTotal)); - readCharacter(state.inputOffset() - 1, character); + 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) + 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(state, nonWordCharThenNonWordChar, nonWordCharThenWordChar); + if (term->invert()) { + matchAssertionWordchar(opIndex, nonWordCharThenNonWordChar, nonWordCharThenWordChar); nonWordCharThenWordChar.append(jump()); } else { - matchAssertionWordchar(state, nonWordCharThenWordChar, nonWordCharThenNonWordChar); + matchAssertionWordchar(opIndex, nonWordCharThenWordChar, nonWordCharThenNonWordChar); nonWordCharThenNonWordChar.append(jump()); } - state.jumpToBacktrack(this, nonWordCharThenNonWordChar); + 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(state, wordCharThenNonWordChar, wordCharThenWordChar); + if (term->invert()) { + matchAssertionWordchar(opIndex, wordCharThenNonWordChar, wordCharThenWordChar); wordCharThenWordChar.append(jump()); } else { - matchAssertionWordchar(state, wordCharThenWordChar, wordCharThenNonWordChar); + matchAssertionWordchar(opIndex, wordCharThenWordChar, wordCharThenNonWordChar); // This can fall-though! } - state.jumpToBacktrack(this, wordCharThenWordChar); + op.m_jumps.append(wordCharThenWordChar); nonWordCharThenWordChar.link(this); wordCharThenNonWordChar.link(this); } + void backtrackAssertionWordBoundary(size_t opIndex) + { + backtrackTermDefault(opIndex); + } - void generatePatternCharacterSingle(TermGenerationState& state) + void generatePatternCharacterOnce(size_t opIndex) { + YarrOp& op = m_ops[opIndex]; + + // 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]; + + if (op.m_isDeadCode) + return; + + PatternTerm* term = op.m_term; + UChar ch = term->patternCharacter; + const RegisterID character = regT0; - UChar ch = state.term().patternCharacter; + + if (nextOp.m_op == OpTerm) { + PatternTerm* nextTerm = nextOp.m_term; + if (nextTerm->type == PatternTerm::TypePatternCharacter + && nextTerm->quantityType == QuantifierFixedCount + && nextTerm->quantityCount == 1 + && nextTerm->inputPosition == (term->inputPosition + 1)) { + + UChar ch2 = nextTerm->patternCharacter; + + int mask = 0; + int chPair = ch | (ch2 << 16); + + if (m_pattern.m_ignoreCase) { + if (isASCIIAlpha(ch)) + mask |= 32; + if (isASCIIAlpha(ch2)) + mask |= 32 << 16; + } + + BaseIndex address(input, index, TimesTwo, (term->inputPosition - m_checked) * sizeof(UChar)); + if (mask) { + load32WithUnalignedHalfWords(address, character); + or32(Imm32(mask), character); + op.m_jumps.append(branch32(NotEqual, character, Imm32(chPair | mask))); + } else + op.m_jumps.append(branch32WithUnalignedHalfWords(NotEqual, address, Imm32(chPair))); + + nextOp.m_isDeadCode = true; + return; + } + } if (m_pattern.m_ignoreCase && isASCIIAlpha(ch)) { - readCharacter(state.inputOffset(), character); + readCharacter(term->inputPosition - m_checked, character); or32(TrustedImm32(32), character); - state.jumpToBacktrack(this, branch32(NotEqual, character, Imm32(Unicode::toLower(ch)))); + op.m_jumps.append(branch32(NotEqual, character, Imm32(Unicode::toLower(ch)))); } else { ASSERT(!m_pattern.m_ignoreCase || (Unicode::toLower(ch) == Unicode::toUpper(ch))); - state.jumpToBacktrack(this, jumpIfCharNotEquals(ch, state.inputOffset())); + op.m_jumps.append(jumpIfCharNotEquals(ch, term->inputPosition - m_checked)); } } - - void generatePatternCharacterPair(TermGenerationState& state) + void backtrackPatternCharacterOnce(size_t opIndex) { - const RegisterID character = regT0; - UChar ch1 = state.term().patternCharacter; - UChar ch2 = state.lookaheadTerm().patternCharacter; - - int mask = 0; - int chPair = ch1 | (ch2 << 16); - - if (m_pattern.m_ignoreCase) { - if (isASCIIAlpha(ch1)) - mask |= 32; - if (isASCIIAlpha(ch2)) - mask |= 32 << 16; - } - - if (mask) { - load32WithUnalignedHalfWords(BaseIndex(input, index, TimesTwo, state.inputOffset() * sizeof(UChar)), character); - or32(Imm32(mask), character); - state.jumpToBacktrack(this, branch32(NotEqual, character, Imm32(chPair | mask))); - } else - state.jumpToBacktrack(this, branch32WithUnalignedHalfWords(NotEqual, BaseIndex(input, index, TimesTwo, state.inputOffset() * sizeof(UChar)), Imm32(chPair))); + backtrackTermDefault(opIndex); } - void generatePatternCharacterFixed(TermGenerationState& state) + 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; - PatternTerm& term = state.term(); - UChar ch = term.patternCharacter; move(index, countRegister); - sub32(Imm32(term.quantityCount), countRegister); + sub32(Imm32(term->quantityCount), countRegister); Label loop(this); + BaseIndex address(input, countRegister, TimesTwo, (term->inputPosition - m_checked + term->quantityCount) * sizeof(UChar)); + if (m_pattern.m_ignoreCase && isASCIIAlpha(ch)) { - load16(BaseIndex(input, countRegister, TimesTwo, (state.inputOffset() + term.quantityCount) * sizeof(UChar)), character); + load16(address, character); or32(TrustedImm32(32), character); - state.jumpToBacktrack(this, branch32(NotEqual, character, Imm32(Unicode::toLower(ch)))); + op.m_jumps.append(branch32(NotEqual, character, Imm32(Unicode::toLower(ch)))); } else { ASSERT(!m_pattern.m_ignoreCase || (Unicode::toLower(ch) == Unicode::toUpper(ch))); - state.jumpToBacktrack(this, branch16(NotEqual, BaseIndex(input, countRegister, TimesTwo, (state.inputOffset() + term.quantityCount) * sizeof(UChar)), Imm32(ch))); + op.m_jumps.append(branch16(NotEqual, address, Imm32(ch))); } add32(TrustedImm32(1), countRegister); branch32(NotEqual, countRegister, index).linkTo(loop, this); } + void backtrackPatternCharacterFixed(size_t opIndex) + { + backtrackTermDefault(opIndex); + } - void generatePatternCharacterGreedy(TermGenerationState& state) + 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; - PatternTerm& term = state.term(); - UChar ch = term.patternCharacter; move(TrustedImm32(0), countRegister); @@ -1352,121 +752,152 @@ class YarrGenerator : private MacroAssembler { Label loop(this); failures.append(atEndOfInput()); if (m_pattern.m_ignoreCase && isASCIIAlpha(ch)) { - readCharacter(state.inputOffset(), character); + readCharacter(term->inputPosition - m_checked, character); or32(TrustedImm32(32), character); failures.append(branch32(NotEqual, character, Imm32(Unicode::toLower(ch)))); } else { ASSERT(!m_pattern.m_ignoreCase || (Unicode::toLower(ch) == Unicode::toUpper(ch))); - failures.append(jumpIfCharNotEquals(ch, state.inputOffset())); + failures.append(jumpIfCharNotEquals(ch, term->inputPosition - m_checked)); } add32(TrustedImm32(1), countRegister); add32(TrustedImm32(1), index); - if (term.quantityCount != quantifyInfinite) { - branch32(NotEqual, countRegister, Imm32(term.quantityCount)).linkTo(loop, this); - failures.append(jump()); - } else + if (term->quantityCount == quantifyInfinite) jump(loop); - - Label backtrackBegin(this); - loadFromFrame(term.frameLocation, countRegister); - state.jumpToBacktrack(this, branchTest32(Zero, countRegister)); - sub32(TrustedImm32(1), countRegister); - sub32(TrustedImm32(1), index); + else + branch32(NotEqual, countRegister, Imm32(term->quantityCount)).linkTo(loop, this); failures.link(this); + op.m_reentry = label(); - storeToFrame(countRegister, term.frameLocation); + storeToFrame(countRegister, term->frameLocation); - state.setBacktrackLabel(backtrackBegin); } + void backtrackPatternCharacterGreedy(size_t opIndex) + { + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + + const RegisterID countRegister = regT1; - void generatePatternCharacterNonGreedy(TermGenerationState& state) + 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) { - const RegisterID character = regT0; + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + const RegisterID countRegister = regT1; - PatternTerm& term = state.term(); - UChar ch = term.patternCharacter; 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; - Jump firstTimeDoNothing = jump(); + JumpList nonGreedyFailures; - Label hardFail(this); - sub32(countRegister, index); - state.jumpToBacktrack(this); + m_backtrackingState.link(this); - Label backtrackBegin(this); - loadFromFrame(term.frameLocation, countRegister); + loadFromFrame(term->frameLocation, countRegister); - atEndOfInput().linkTo(hardFail, this); - if (term.quantityCount != quantifyInfinite) - branch32(Equal, countRegister, Imm32(term.quantityCount), hardFail); + nonGreedyFailures.append(atEndOfInput()); + if (term->quantityCount != quantifyInfinite) + nonGreedyFailures.append(branch32(Equal, countRegister, Imm32(term->quantityCount))); if (m_pattern.m_ignoreCase && isASCIIAlpha(ch)) { - readCharacter(state.inputOffset(), character); + readCharacter(term->inputPosition - m_checked, character); or32(TrustedImm32(32), character); - branch32(NotEqual, character, Imm32(Unicode::toLower(ch))).linkTo(hardFail, this); + nonGreedyFailures.append(branch32(NotEqual, character, Imm32(Unicode::toLower(ch)))); } else { ASSERT(!m_pattern.m_ignoreCase || (Unicode::toLower(ch) == Unicode::toUpper(ch))); - jumpIfCharNotEquals(ch, state.inputOffset()).linkTo(hardFail, this); + nonGreedyFailures.append(jumpIfCharNotEquals(ch, term->inputPosition - m_checked)); } add32(TrustedImm32(1), countRegister); add32(TrustedImm32(1), index); - firstTimeDoNothing.link(this); - storeToFrame(countRegister, term.frameLocation); + jump(op.m_reentry); - state.setBacktrackLabel(backtrackBegin); + nonGreedyFailures.link(this); + sub32(countRegister, index); + m_backtrackingState.fallthrough(); } - void generateCharacterClassSingle(TermGenerationState& state) + void generateCharacterClassOnce(size_t opIndex) { + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + const RegisterID character = regT0; - PatternTerm& term = state.term(); JumpList matchDest; - readCharacter(state.inputOffset(), character); - matchCharacterClass(character, matchDest, term.characterClass); + readCharacter((term->inputPosition - m_checked), character); + matchCharacterClass(character, matchDest, term->characterClass); - if (term.invert()) - state.jumpToBacktrack(this, matchDest); + if (term->invert()) + op.m_jumps.append(matchDest); else { - state.jumpToBacktrack(this); + op.m_jumps.append(jump()); matchDest.link(this); } } + void backtrackCharacterClassOnce(size_t opIndex) + { + backtrackTermDefault(opIndex); + } - void generateCharacterClassFixed(TermGenerationState& state) + void generateCharacterClassFixed(size_t opIndex) { + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + const RegisterID character = regT0; const RegisterID countRegister = regT1; - PatternTerm& term = state.term(); move(index, countRegister); - sub32(Imm32(term.quantityCount), countRegister); + sub32(Imm32(term->quantityCount), countRegister); Label loop(this); JumpList matchDest; - load16(BaseIndex(input, countRegister, TimesTwo, (state.inputOffset() + term.quantityCount) * sizeof(UChar)), character); - matchCharacterClass(character, matchDest, term.characterClass); + load16(BaseIndex(input, countRegister, TimesTwo, (term->inputPosition - m_checked + term->quantityCount) * sizeof(UChar)), character); + matchCharacterClass(character, matchDest, term->characterClass); - if (term.invert()) - state.jumpToBacktrack(this, matchDest); + if (term->invert()) + op.m_jumps.append(matchDest); else { - state.jumpToBacktrack(this); + 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(TermGenerationState& state) + void generateCharacterClassGreedy(size_t opIndex) { + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + const RegisterID character = regT0; const RegisterID countRegister = regT1; - PatternTerm& term = state.term(); move(TrustedImm32(0), countRegister); @@ -1474,692 +905,1356 @@ class YarrGenerator : private MacroAssembler { Label loop(this); failures.append(atEndOfInput()); - if (term.invert()) { - readCharacter(state.inputOffset(), character); - matchCharacterClass(character, failures, term.characterClass); + if (term->invert()) { + readCharacter(term->inputPosition - m_checked, character); + matchCharacterClass(character, failures, term->characterClass); } else { JumpList matchDest; - readCharacter(state.inputOffset(), character); - matchCharacterClass(character, matchDest, term.characterClass); + 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)).linkTo(loop, this); + if (term->quantityCount != quantifyInfinite) { + branch32(NotEqual, countRegister, Imm32(term->quantityCount)).linkTo(loop, this); failures.append(jump()); } else jump(loop); - Label backtrackBegin(this); - loadFromFrame(term.frameLocation, countRegister); - state.jumpToBacktrack(this, branchTest32(Zero, countRegister)); - sub32(TrustedImm32(1), countRegister); - sub32(TrustedImm32(1), index); - 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; - storeToFrame(countRegister, term.frameLocation); + const RegisterID countRegister = regT1; + + m_backtrackingState.link(this); - state.setBacktrackLabel(backtrackBegin); + loadFromFrame(term->frameLocation, countRegister); + m_backtrackingState.append(branchTest32(Zero, countRegister)); + sub32(TrustedImm32(1), countRegister); + sub32(TrustedImm32(1), index); + jump(op.m_reentry); } - void generateCharacterClassNonGreedy(TermGenerationState& state) + void generateCharacterClassNonGreedy(size_t opIndex) { - const RegisterID character = regT0; + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; + const RegisterID countRegister = regT1; - PatternTerm& term = state.term(); 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; - Jump firstTimeDoNothing = jump(); + const RegisterID character = regT0; + const RegisterID countRegister = regT1; - Label hardFail(this); - sub32(countRegister, index); - state.jumpToBacktrack(this); + JumpList nonGreedyFailures; + + m_backtrackingState.link(this); Label backtrackBegin(this); - loadFromFrame(term.frameLocation, countRegister); + loadFromFrame(term->frameLocation, countRegister); - atEndOfInput().linkTo(hardFail, this); - branch32(Equal, countRegister, Imm32(term.quantityCount), hardFail); + nonGreedyFailures.append(atEndOfInput()); + nonGreedyFailures.append(branch32(Equal, countRegister, Imm32(term->quantityCount))); JumpList matchDest; - readCharacter(state.inputOffset(), character); - matchCharacterClass(character, matchDest, term.characterClass); + readCharacter(term->inputPosition - m_checked, character); + matchCharacterClass(character, matchDest, term->characterClass); - if (term.invert()) - matchDest.linkTo(hardFail, this); + if (term->invert()) + nonGreedyFailures.append(matchDest); else { - jump(hardFail); + nonGreedyFailures.append(jump()); matchDest.link(this); } add32(TrustedImm32(1), countRegister); add32(TrustedImm32(1), index); - firstTimeDoNothing.link(this); - storeToFrame(countRegister, term.frameLocation); + jump(op.m_reentry); - state.setBacktrackLabel(backtrackBegin); + nonGreedyFailures.link(this); + sub32(countRegister, index); + m_backtrackingState.fallthrough(); } - void generateParenthesesDisjunction(PatternTerm& parenthesesTerm, TermGenerationState& state, unsigned alternativeFrameLocation) + // 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) { - ASSERT((parenthesesTerm.type == PatternTerm::TypeParenthesesSubpattern) || (parenthesesTerm.type == PatternTerm::TypeParentheticalAssertion)); - ASSERT(parenthesesTerm.quantityCount == 1); + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; - PatternDisjunction* disjunction = parenthesesTerm.parentheses.disjunction; - unsigned preCheckedCount = ((parenthesesTerm.quantityType == QuantifierFixedCount) && (parenthesesTerm.type != PatternTerm::TypeParentheticalAssertion)) ? disjunction->m_minimumSize : 0; + 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; - if (disjunction->m_alternatives.size() == 1) { - state.resetAlternative(); - ASSERT(state.alternativeValid()); - PatternAlternative* alternative = state.alternative(); - optimizeAlternative(alternative); + 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; - int countToCheck = alternative->m_minimumSize - preCheckedCount; - if (countToCheck) { - ASSERT((parenthesesTerm.type == PatternTerm::TypeParentheticalAssertion) || (parenthesesTerm.quantityType != QuantifierFixedCount)); + case PatternTerm::TypeAssertionBOL: + generateAssertionBOL(opIndex); + break; - // FIXME: This is quite horrible. The call to 'plantJumpToBacktrackIfExists' - // will be forced to always trampoline into here, just to decrement the index. - // Ick. - Jump skip = jump(); + case PatternTerm::TypeAssertionEOL: + generateAssertionEOL(opIndex); + break; - Label backtrackBegin(this); - sub32(Imm32(countToCheck), index); - state.addBacktrackJump(jump()); + case PatternTerm::TypeAssertionWordBoundary: + generateAssertionWordBoundary(opIndex); + break; - skip.link(this); + case PatternTerm::TypeForwardReference: + break; - state.setBacktrackLabel(backtrackBegin); + case PatternTerm::TypeParenthesesSubpattern: + case PatternTerm::TypeParentheticalAssertion: + ASSERT_NOT_REACHED(); + case PatternTerm::TypeBackReference: + m_shouldFallBack = true; + break; + } + } + void backtrackTerm(size_t opIndex) + { + YarrOp& op = m_ops[opIndex]; + PatternTerm* term = op.m_term; - state.jumpToBacktrack(this, jumpIfNoAvailableInput(countToCheck)); - state.checkedTotal += countToCheck; + 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; - for (state.resetTerm(); state.termValid(); state.nextTerm()) - generateTerm(state); - - state.checkedTotal -= countToCheck; - } else { - JumpList successes; - bool propogateBacktrack = false; - - // Save current state's paren jump list for use with each alternative - JumpList* outerJumpList = state.getJumpListToPriorParen(); + 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; - for (state.resetAlternative(); state.alternativeValid(); state.nextAlternative(), state.setJumpListToPriorParen(outerJumpList)) { - PatternAlternative* alternative = state.alternative(); - optimizeAlternative(alternative); + case PatternTerm::TypeAssertionBOL: + backtrackAssertionBOL(opIndex); + break; - ASSERT(alternative->m_minimumSize >= preCheckedCount); - int countToCheck = alternative->m_minimumSize - preCheckedCount; - if (countToCheck) { - state.addBacktrackJump(jumpIfNoAvailableInput(countToCheck)); - state.checkedTotal += countToCheck; - } + case PatternTerm::TypeAssertionEOL: + backtrackAssertionEOL(opIndex); + break; - for (state.resetTerm(); state.termValid(); state.nextTerm()) - generateTerm(state); + case PatternTerm::TypeAssertionWordBoundary: + backtrackAssertionWordBoundary(opIndex); + break; - // Matched an alternative. - DataLabelPtr dataLabel = storeToFrameWithPatch(alternativeFrameLocation); + case PatternTerm::TypeForwardReference: + break; - if (!state.isLastAlternative() || countToCheck) - successes.append(jump()); + case PatternTerm::TypeParenthesesSubpattern: + case PatternTerm::TypeParentheticalAssertion: + ASSERT_NOT_REACHED(); + case PatternTerm::TypeBackReference: + m_shouldFallBack = true; + break; + } + } - // Alternative did not match. + void generate() + { + // Forwards generate the matching code. + ASSERT(m_ops.size()); + size_t opIndex = 0; - // Do we have a backtrack destination? - // if so, link the data label to it. - state.linkDataLabelToBacktrackIfExists(this, dataLabel); + do { + YarrOp& op = m_ops[opIndex]; + switch (op.m_op) { - if (!state.isLastAlternative() || countToCheck) - state.linkAlternativeBacktracks(this); + case OpTerm: + generateTerm(opIndex); + break; - if (countToCheck) { - sub32(Imm32(countToCheck), index); - state.checkedTotal -= countToCheck; - } else if (state.isLastAlternative()) - propogateBacktrack = true; + // 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; } - // We fall through to here when the last alternative fails. - // Add a backtrack out of here for the parenthese handling code to link up. - if (!propogateBacktrack) - state.addBacktrackJump(jump()); - - // Save address on stack for the parens code to backtrack to, to retry the - // next alternative. - state.setBackTrackStackOffset(alternativeFrameLocation * sizeof(void*)); - - successes.link(this); - } - } + 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. + if (m_pattern.m_body->m_callFrameSize) + addPtr(Imm32(m_pattern.m_body->m_callFrameSize * sizeof(void*)), stackPointerRegister); + + // 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); + store32(returnRegister, output); + } else + load32(Address(output), returnRegister); + store32(index, Address(output, 4)); + 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 (int delta = alternative->m_minimumSize - priorAlternative->m_minimumSize) { + add32(Imm32(delta), index); + if (delta > 0) + op.m_jumps.append(jumpIfNoAvailableInput()); + } + } else if (op.m_nextOp == notFound) { + // This is the reentry point for the End of 'once through' alternatives, + // jumped to when the las alternative fails to match. + op.m_reentry = label(); + sub32(Imm32(priorAlternative->m_minimumSize), index); + } - void generateParenthesesSingle(TermGenerationState& state) - { - const RegisterID indexTemporary = regT0; - PatternTerm& term = state.term(); - PatternDisjunction* disjunction = term.parentheses.disjunction; - ASSERT(term.quantityCount == 1); + if (op.m_op == OpBodyAlternativeNext) + m_checked += alternative->m_minimumSize; + m_checked -= priorAlternative->m_minimumSize; + break; + } - unsigned preCheckedCount = (term.quantityType == QuantifierFixedCount) ? disjunction->m_minimumSize : 0; + // 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); + } - unsigned parenthesesFrameLocation = term.frameLocation; - unsigned alternativeFrameLocation = parenthesesFrameLocation; - if (term.quantityType != QuantifierFixedCount) - alternativeFrameLocation += YarrStackSpaceForBackTrackInfoParenthesesOnce; + // 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); + } - // optimized case - no capture & no quantifier can be handled in a light-weight manner. - if (!term.capture() && (term.quantityType == QuantifierFixedCount)) { - m_expressionState.incrementParenNestingLevel(); + // 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(); - TermGenerationState parenthesesState(disjunction, state.checkedTotal); + YarrOp& lastOp = m_ops[op.m_previousOp]; + m_checked -= lastOp.m_checkAdjust; + break; + } - // Use the current state's jump list for the nested parentheses. - parenthesesState.setJumpListToPriorParen(state.getJumpListToPriorParen()); + // 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); + } - generateParenthesesDisjunction(state.term(), parenthesesState, alternativeFrameLocation); - // this expects that any backtracks back out of the parentheses will be in the - // parenthesesState's m_backTrackJumps vector, and that if they need backtracking - // they will have set an entry point on the parenthesesState's m_backtrackLabel. - BacktrackDestination& parenthesesBacktrack = parenthesesState.getBacktrackDestination(); - BacktrackDestination& stateBacktrack = state.getBacktrackDestination(); + // 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()) { + int offsetId = term->parentheses.subpatternId << 1; + 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); + store32(indexTemporary, Address(output, offsetId * sizeof(int))); + } else + store32(index, Address(output, offsetId * sizeof(int))); + } + break; + } + case OpParenthesesSubpatternOnceEnd: { + PatternTerm* term = op.m_term; + unsigned parenthesesFrameLocation = term->frameLocation; + const RegisterID indexTemporary = regT0; + ASSERT(term->quantityCount == 1); + + // For Greedy/NonGreedy quantified parentheses, we must reject zero length + // matches. If the minimum size is know to be non-zero we need not check. + if (term->quantityType != QuantifierFixedCount && !term->parentheses.disjunction->m_minimumSize) + op.m_jumps.append(branch32(Equal, index, Address(stackPointerRegister, parenthesesFrameLocation * sizeof(void*)))); + + // 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()) { + int offsetId = (term->parentheses.subpatternId << 1) + 1; + int inputOffset = term->inputPosition - m_checked; + if (inputOffset) { + move(index, indexTemporary); + add32(Imm32(inputOffset), indexTemporary); + store32(indexTemporary, Address(output, offsetId * sizeof(int))); + } else + store32(index, Address(output, offsetId * sizeof(int))); + } - state.propagateBacktrackingFrom(this, parenthesesBacktrack); - stateBacktrack.propagateBacktrackToLabel(parenthesesBacktrack); + // 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; + } - state.setJumpListToPriorParen(parenthesesState.getJumpListToPriorParen()); + // OpParenthesesSubpatternTerminalBegin/End + case OpParenthesesSubpatternTerminalBegin: { + PatternTerm* term = op.m_term; + ASSERT(term->quantityType == QuantifierGreedy); + ASSERT(term->quantityCount == quantifyInfinite); + ASSERT(!term->capture()); - m_expressionState.decrementParenNestingLevel(); - } else { - Jump nonGreedySkipParentheses; - Label nonGreedyTryParentheses; - if (term.quantityType == QuantifierGreedy) - storeToFrame(index, parenthesesFrameLocation); - else if (term.quantityType == QuantifierNonGreedy) { - storeToFrame(TrustedImm32(-1), parenthesesFrameLocation); - nonGreedySkipParentheses = jump(); - nonGreedyTryParentheses = label(); - storeToFrame(index, parenthesesFrameLocation); - } + // Upon entry set a label to loop back to. + op.m_reentry = label(); - // store the match start index - if (term.capture()) { - int inputOffset = state.inputOffset() - preCheckedCount; - if (inputOffset) { - move(index, indexTemporary); - add32(Imm32(inputOffset), indexTemporary); - store32(indexTemporary, Address(output, (term.parentheses.subpatternId << 1) * sizeof(int))); - } else - store32(index, Address(output, (term.parentheses.subpatternId << 1) * sizeof(int))); + // Store the start index of the current match; we need to reject zero + // length matches. + storeToFrame(index, term->frameLocation); + break; } + case OpParenthesesSubpatternTerminalEnd: { + PatternTerm* term = op.m_term; - ParenthesesTail* parenthesesTail = m_expressionState.addParenthesesTail(term, state.getJumpListToPriorParen()); + // Check for zero length matches - if the match is non-zero, then we + // can accept it & loop back up to the head of the subpattern. + YarrOp& beginOp = m_ops[op.m_previousOp]; + branch32(NotEqual, index, Address(stackPointerRegister, term->frameLocation * sizeof(void*)), beginOp.m_reentry); - m_expressionState.incrementParenNestingLevel(); + // Reject the match - backtrack back into the subpattern. + op.m_jumps.append(jump()); - TermGenerationState parenthesesState(disjunction, state.checkedTotal); + // 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; + } - // Save the parenthesesTail for backtracking from nested parens to this one. - parenthesesState.setJumpListToPriorParen(&parenthesesTail->m_withinBacktrackJumps); + // OpParentheticalAssertionBegin/End + case OpParentheticalAssertionBegin: { + PatternTerm* term = op.m_term; - // generate the body of the parentheses - generateParenthesesDisjunction(state.term(), parenthesesState, alternativeFrameLocation); + // 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); - // For non-fixed counts, backtrack if we didn't match anything. - if (term.quantityType != QuantifierFixedCount) - parenthesesTail->addAfterParenJump(branch32(Equal, index, Address(stackPointerRegister, (parenthesesFrameLocation * sizeof(void*))))); + // Check + op.m_checkAdjust = m_checked - term->inputPosition; + if (op.m_checkAdjust) + sub32(Imm32(op.m_checkAdjust), index); - // store the match end index - if (term.capture()) { - int inputOffset = state.inputOffset(); - if (inputOffset) { - move(index, indexTemporary); - add32(Imm32(state.inputOffset()), indexTemporary); - store32(indexTemporary, Address(output, ((term.parentheses.subpatternId << 1) + 1) * sizeof(int))); - } else - store32(index, Address(output, ((term.parentheses.subpatternId << 1) + 1) * sizeof(int))); + 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(); + } - m_expressionState.decrementParenNestingLevel(); - - parenthesesTail->processBacktracks(this, state, parenthesesState, nonGreedyTryParentheses, label()); + YarrOp& lastOp = m_ops[op.m_previousOp]; + m_checked += lastOp.m_checkAdjust; + break; + } - state.setJumpListToPriorParen(&parenthesesTail->m_afterBacktrackJumps); - - parenthesesState.getBacktrackDestination().clear(); + case OpMatchFailed: + if (m_pattern.m_body->m_callFrameSize) + addPtr(Imm32(m_pattern.m_body->m_callFrameSize * sizeof(void*)), stackPointerRegister); + move(TrustedImm32(-1), returnRegister); + generateReturn(); + break; + } - if (term.quantityType == QuantifierNonGreedy) - nonGreedySkipParentheses.link(this); - } + ++opIndex; + } while (opIndex < m_ops.size()); } - void generateParenthesesGreedyNoBacktrack(TermGenerationState& state) + void backtrack() { - PatternTerm& parenthesesTerm = state.term(); - PatternDisjunction* disjunction = parenthesesTerm.parentheses.disjunction; - ASSERT(parenthesesTerm.type == PatternTerm::TypeParenthesesSubpattern); - ASSERT(parenthesesTerm.quantityCount != 1); // Handled by generateParenthesesSingle. + // Backwards generate the backtracking code. + size_t opIndex = m_ops.size(); + ASSERT(opIndex); - TermGenerationState parenthesesState(disjunction, state.checkedTotal); + do { + --opIndex; + YarrOp& op = m_ops[opIndex]; + switch (op.m_op) { - Label matchAgain(this); + case OpTerm: + backtrackTerm(opIndex); + break; - storeToFrame(index, parenthesesTerm.frameLocation); // Save the current index to check for zero len matches later. + // 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; - for (parenthesesState.resetAlternative(); parenthesesState.alternativeValid(); parenthesesState.nextAlternative()) { + // 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]; - PatternAlternative* alternative = parenthesesState.alternative(); - optimizeAlternative(alternative); + YarrOp* beginOp = &op; + while (beginOp->m_op != OpBodyAlternativeBegin) { + ASSERT(beginOp->m_op == OpBodyAlternativeNext); + beginOp = &m_ops[beginOp->m_previousOp]; + } - int countToCheck = alternative->m_minimumSize; - if (countToCheck) { - parenthesesState.addBacktrackJump(jumpIfNoAvailableInput(countToCheck)); - parenthesesState.checkedTotal += countToCheck; - } + 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 { + // Okay, we're going to need to loop. Calculate the delta between where the input + // position was, and where we want it to be allowing for the fact that we need to + // increment by 1. E.g. for the regexp /a|x/ we need to increment the position by + // 1 between loop iterations, but for /abcd|xyz/ we need to increment by two when + // looping from the last alternative to the first, for /a|xyz/ we need to decrement + // by 1, and for /a|xy/ we don't need to move the input position at all. + int deltaLastAlternativeToFirstAlternativePlusOne = (beginOp->m_alternative->m_minimumSize - alternative->m_minimumSize) + 1; + + // 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 (!deltaLastAlternativeToFirstAlternativePlusOne && m_pattern.m_body->m_hasFixedSize) + 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) + store32(index, Address(output)); + else { + move(index, regT0); + if (alternative->m_minimumSize) + sub32(Imm32(alternative->m_minimumSize - 1), regT0); + else + add32(Imm32(1), regT0); + store32(regT0, Address(output)); + } + } + + if (deltaLastAlternativeToFirstAlternativePlusOne) + add32(Imm32(deltaLastAlternativeToFirstAlternativePlusOne), index); + + // Loop. Since this code is only reached when we backtrack out of the last + // alternative (and NOT linked to from the input check upon entry to the + // last alternative) we know that there must be at least enough input as + // required by the last alternative. As such, we only need to check if the + // first will require more to run - if the same or less is required we can + // unconditionally jump. + if (deltaLastAlternativeToFirstAlternativePlusOne > 0) + checkInput().linkTo(beginOp->m_reentry, this); + else + jump(beginOp->m_reentry); + } + } - for (parenthesesState.resetTerm(); parenthesesState.termValid(); parenthesesState.nextTerm()) - generateTerm(parenthesesState); + // 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); + + int delta = nextOp->m_alternative->m_minimumSize - prevOp->m_alternative->m_minimumSize; + if (delta) + add32(Imm32(delta), index); + + // 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 (delta < 0) { + // 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. + Jump fail = jumpIfNoAvailableInput(); + sub32(Imm32(delta), index); + jump(nextOp->m_reentry); + fail.link(this); + } + prevOp = nextOp; + nextOp = &m_ops[nextOp->m_nextOp]; + } - // If we get here, we matched! If the index advanced then try to match more since limit isn't supported yet. - branch32(NotEqual, index, Address(stackPointerRegister, (parenthesesTerm.frameLocation * sizeof(void*))), matchAgain); + // We fall through to here if there is insufficient input to run the last alternative. - // If we get here we matched, but we matched "" - cannot accept this alternative as is, so either backtrack, - // or fall through to try the next alternative if no backtrack is available. - parenthesesState.plantJumpToBacktrackIfExists(this); + // 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; + } - parenthesesState.linkAlternativeBacktracks(this); + // For repeating alternatives, link any input check failure from the last alternative to + // this point. + op.m_jumps.link(this); - // We get here if the alternative fails to match - fall through to the next iteration, or out of the loop. + bool needsToUpdateMatchStart = !m_pattern.m_body->m_hasFixedSize; - if (countToCheck) { - sub32(Imm32(countToCheck), index); - parenthesesState.checkedTotal -= countToCheck; - } - } + // 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! + store32(index, Address(output)); + needsToUpdateMatchStart = false; + } - // If the last alternative falls through to here, we have a failed match... - // Which means that we match whatever we have matched up to this point (even if nothing). - } + // 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. + int deltaLastAlternativeToBodyMinimumPlusOne = (m_pattern.m_body->m_minimumSize + 1) - alternative->m_minimumSize; + if (deltaLastAlternativeToBodyMinimumPlusOne) + add32(Imm32(deltaLastAlternativeToBodyMinimumPlusOne), index); + Jump matchFailed = jumpIfNoAvailableInput(); + + if (needsToUpdateMatchStart) { + if (!m_pattern.m_body->m_minimumSize) + store32(index, Address(output)); + else { + move(index, regT0); + sub32(Imm32(m_pattern.m_body->m_minimumSize), regT0); + store32(regT0, Address(output)); + } + } - void generateParentheticalAssertion(TermGenerationState& state) - { - PatternTerm& term = state.term(); - PatternDisjunction* disjunction = term.parentheses.disjunction; - ASSERT(term.quantityCount == 1); - ASSERT(term.quantityType == QuantifierFixedCount); + // 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. + int deltaBodyMinimumToFirstAlternative = beginOp->m_alternative->m_minimumSize - m_pattern.m_body->m_minimumSize; + if (!deltaBodyMinimumToFirstAlternative) + jump(beginOp->m_reentry); + else { + add32(Imm32(deltaBodyMinimumToFirstAlternative), index); + checkInput().linkTo(beginOp->m_reentry, this); + jump(firstInputCheckFailed); + } - unsigned parenthesesFrameLocation = term.frameLocation; - unsigned alternativeFrameLocation = parenthesesFrameLocation + YarrStackSpaceForBackTrackInfoParentheticalAssertion; + // 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); - int countCheckedAfterAssertion = state.checkedTotal - term.inputPosition; + if (m_pattern.m_body->m_callFrameSize) + addPtr(Imm32(m_pattern.m_body->m_callFrameSize * sizeof(void*)), stackPointerRegister); + move(TrustedImm32(-1), returnRegister); + generateReturn(); + break; + } + case OpBodyAlternativeEnd: { + // We should never backtrack back into a body disjunction. + ASSERT(m_backtrackingState.isEmpty()); - if (term.invert()) { - // Inverted case - storeToFrame(index, parenthesesFrameLocation); + PatternAlternative* priorAlternative = m_ops[op.m_previousOp].m_alternative; + m_checked += priorAlternative->m_minimumSize; + break; + } - state.checkedTotal -= countCheckedAfterAssertion; - if (countCheckedAfterAssertion) - sub32(Imm32(countCheckedAfterAssertion), index); + // 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 begnning. + 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 begnning. + m_backtrackingState.takeBacktracksToJumpList(nextOp.m_jumps, this); + } + // In the case of a single alternative on its own do nothing - it can fall through. + } - TermGenerationState parenthesesState(disjunction, state.checkedTotal); - generateParenthesesDisjunction(state.term(), parenthesesState, alternativeFrameLocation); - // Success! - which means - Fail! - loadFromFrame(parenthesesFrameLocation, index); - state.jumpToBacktrack(this); + // 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); + } - // And fail means success. - parenthesesState.linkAlternativeBacktracks(this); + 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 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); + } - loadFromFrame(parenthesesFrameLocation, index); + YarrOp& lastOp = m_ops[op.m_previousOp]; + m_checked += lastOp.m_checkAdjust; + break; + } - state.checkedTotal += countCheckedAfterAssertion; - } else { - // Normal case - storeToFrame(index, parenthesesFrameLocation); + // 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() || term->quantityType == QuantifierGreedy) { + m_backtrackingState.link(this); + + // If capturing, clear the capture (we only need to reset start). + if (term->capture()) + store32(TrustedImm32(-1), Address(output, (term->parentheses.subpatternId << 1) * sizeof(int))); + + // 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); + } - state.checkedTotal -= countCheckedAfterAssertion; - if (countCheckedAfterAssertion) - sub32(Imm32(countCheckedAfterAssertion), index); + 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); + } - TermGenerationState parenthesesState(disjunction, state.checkedTotal); - generateParenthesesDisjunction(state.term(), parenthesesState, alternativeFrameLocation); - // Success! - which means - Success! - loadFromFrame(parenthesesFrameLocation, index); - Jump success = jump(); + m_backtrackingState.fallthrough(); + } - parenthesesState.linkAlternativeBacktracks(this); + m_backtrackingState.append(op.m_jumps); + break; + } - loadFromFrame(parenthesesFrameLocation, index); - state.jumpToBacktrack(this); + // 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; - success.link(this); + // OpParentheticalAssertionBegin/End + case OpParentheticalAssertionBegin: { + PatternTerm* term = op.m_term; + YarrOp& endOp = m_ops[op.m_nextOp]; - state.checkedTotal += countCheckedAfterAssertion; - } - } + // 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); - void generateTerm(TermGenerationState& state) - { - PatternTerm& term = state.term(); + if (op.m_checkAdjust) + add32(Imm32(op.m_checkAdjust), index); - switch (term.type) { - case PatternTerm::TypeAssertionBOL: - generateAssertionBOL(state); - break; + // 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); - case PatternTerm::TypeAssertionEOL: - generateAssertionEOL(state); - break; + m_backtrackingState.fallthrough(); + } - case PatternTerm::TypeAssertionWordBoundary: - generateAssertionWordBoundary(state); - break; + // 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); - case PatternTerm::TypePatternCharacter: - switch (term.quantityType) { - case QuantifierFixedCount: - if (term.quantityCount == 1) { - if (state.isSinglePatternCharacterLookaheadTerm() && (state.lookaheadTerm().inputPosition == (term.inputPosition + 1))) { - generatePatternCharacterPair(state); - state.nextTerm(); - } else - generatePatternCharacterSingle(state); - } else - generatePatternCharacterFixed(state); - break; - case QuantifierGreedy: - generatePatternCharacterGreedy(state); - break; - case QuantifierNonGreedy: - generatePatternCharacterNonGreedy(state); + m_checked += op.m_checkAdjust; break; } - 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!) - case PatternTerm::TypeCharacterClass: - switch (term.quantityType) { - case QuantifierFixedCount: - if (term.quantityCount == 1) - generateCharacterClassSingle(state); - else - generateCharacterClassFixed(state); - break; - case QuantifierGreedy: - generateCharacterClassGreedy(state); - break; - case QuantifierNonGreedy: - generateCharacterClassNonGreedy(state); + // 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; } - break; - case PatternTerm::TypeBackReference: - m_shouldFallBack = true; - break; - - case PatternTerm::TypeForwardReference: - break; - - case PatternTerm::TypeParenthesesSubpattern: - if (term.quantityCount == 1 && !term.parentheses.isCopy) - generateParenthesesSingle(state); - else if (term.parentheses.isTerminal) - generateParenthesesGreedyNoBacktrack(state); - else - m_shouldFallBack = true; - break; + case OpMatchFailed: + break; + } - case PatternTerm::TypeParentheticalAssertion: - generateParentheticalAssertion(state); - break; - } + } while (opIndex); } - void generateDisjunction(PatternDisjunction* disjunction) + // 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) { - TermGenerationState state(disjunction, 0); - state.resetAlternative(); - - // check availability for the next alternative - int countCheckedForCurrentAlternative = 0; - int countToCheckForFirstAlternative = 0; - bool hasShorterAlternatives = false; - bool setRepeatAlternativeLabels = false; - JumpList notEnoughInputForPreviousAlternative; - Label firstAlternative; - Label firstAlternativeInputChecked; - - // The label 'firstAlternative' is used to plant a check to see if there is - // sufficient input available to run the first repeating alternative. - // The label 'firstAlternativeInputChecked' will jump directly to matching - // the first repeating alternative having skipped this check. - - if (state.alternativeValid()) { - PatternAlternative* alternative = state.alternative(); - if (!alternative->onceThrough()) { - firstAlternative = Label(this); - setRepeatAlternativeLabels = true; + 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; } - countToCheckForFirstAlternative = alternative->m_minimumSize; - state.checkedTotal += countToCheckForFirstAlternative; - if (countToCheckForFirstAlternative) - notEnoughInputForPreviousAlternative.append(jumpIfNoAvailableInput(countToCheckForFirstAlternative)); - countCheckedForCurrentAlternative = countToCheckForFirstAlternative; + } 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; } - if (setRepeatAlternativeLabels) - firstAlternativeInputChecked = Label(this); - - while (state.alternativeValid()) { - PatternAlternative* alternative = state.alternative(); - optimizeAlternative(alternative); + size_t parenBegin = m_ops.size(); + m_ops.append(parenthesesBeginOpCode); - // Track whether any alternatives are shorter than the first one. - if (!alternative->onceThrough()) - hasShorterAlternatives = hasShorterAlternatives || (countCheckedForCurrentAlternative < countToCheckForFirstAlternative); + 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; - for (state.resetTerm(); state.termValid(); state.nextTerm()) - generateTerm(state); + PatternAlternative* nestedAlternative = alternatives[i]; + opCompileAlternative(nestedAlternative); - // If we get here, the alternative matched. - if (m_pattern.m_body->m_callFrameSize) - addPtr(Imm32(m_pattern.m_body->m_callFrameSize * sizeof(void*)), stackPointerRegister); + size_t thisOpIndex = m_ops.size(); + m_ops.append(YarrOp(alternativeNextOpCode)); - ASSERT(index != returnRegister); - if (m_pattern.m_body->m_hasFixedSize) { - move(index, returnRegister); - if (alternative->m_minimumSize) - sub32(Imm32(alternative->m_minimumSize), returnRegister); - - store32(returnRegister, output); - } else - load32(Address(output), returnRegister); + YarrOp& lastOp = m_ops[lastOpIndex]; + YarrOp& thisOp = m_ops[thisOpIndex]; - store32(index, Address(output, 4)); - - generateReturn(); - - state.nextAlternative(); - if (alternative->onceThrough() && state.alternativeValid()) - state.clearBacktrack(); - - // if there are any more alternatives, plant the check for input before looping. - if (state.alternativeValid()) { - state.setJumpListToPriorParen(0); - PatternAlternative* nextAlternative = state.alternative(); - if (!setRepeatAlternativeLabels && !nextAlternative->onceThrough()) { - // We have handled non-repeating alternatives, jump to next iteration - // and loop over repeating alternatives. - state.jumpToBacktrack(this); - - countToCheckForFirstAlternative = nextAlternative->m_minimumSize; + 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; - // If we get here, there the last input checked failed. - notEnoughInputForPreviousAlternative.link(this); + size_t parenEnd = m_ops.size(); + m_ops.append(parenthesesEndOpCode); - state.linkAlternativeBacktracks(this); + 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; + } - // Back up to start the looping alternatives. - if (countCheckedForCurrentAlternative) - sub32(Imm32(countCheckedForCurrentAlternative), index); + // 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; + } - firstAlternative = Label(this); + // opCompileAlternative + // Called to emit nodes for all terms in an alternative. + void opCompileAlternative(PatternAlternative* alternative) + { + optimizeAlternative(alternative); - state.checkedTotal = countToCheckForFirstAlternative; - if (countToCheckForFirstAlternative) - notEnoughInputForPreviousAlternative.append(jumpIfNoAvailableInput(countToCheckForFirstAlternative)); + for (unsigned i = 0; i < alternative->m_terms.size(); ++i) { + PatternTerm* term = &alternative->m_terms[i]; - countCheckedForCurrentAlternative = countToCheckForFirstAlternative; + switch (term->type) { + case PatternTerm::TypeParenthesesSubpattern: + opCompileParenthesesSubpattern(term); + break; - firstAlternativeInputChecked = Label(this); + case PatternTerm::TypeParentheticalAssertion: + opCompileParentheticalAssertion(term); + break; - setRepeatAlternativeLabels = true; - } else { - int countToCheckForNextAlternative = nextAlternative->m_minimumSize; - - if (countCheckedForCurrentAlternative > countToCheckForNextAlternative) { // CASE 1: current alternative was longer than the next one. - // If we get here, then the last input checked failed. - notEnoughInputForPreviousAlternative.link(this); - - // Check if sufficent input available to run the next alternative - notEnoughInputForPreviousAlternative.append(jumpIfNoAvailableInput(countToCheckForNextAlternative - countCheckedForCurrentAlternative)); - // We are now in the correct state to enter the next alternative; this add is only required - // to mirror and revert operation of the sub32, just below. - add32(Imm32(countCheckedForCurrentAlternative - countToCheckForNextAlternative), index); - - // If we get here, then the last input checked passed. - state.linkAlternativeBacktracks(this); - - // No need to check if we can run the next alternative, since it is shorter - - // just update index. - sub32(Imm32(countCheckedForCurrentAlternative - countToCheckForNextAlternative), index); - } else if (countCheckedForCurrentAlternative < countToCheckForNextAlternative) { // CASE 2: next alternative is longer than the current one. - // If we get here, then the last input checked failed. - // If there is insufficient input to run the current alternative, and the next alternative is longer, - // then there is definitely not enough input to run it - don't even check. Just adjust index, as if - // we had checked. - notEnoughInputForPreviousAlternative.link(this); - add32(Imm32(countToCheckForNextAlternative - countCheckedForCurrentAlternative), index); - notEnoughInputForPreviousAlternative.append(jump()); - - // The next alternative is longer than the current one; check the difference. - state.linkAlternativeBacktracks(this); - - notEnoughInputForPreviousAlternative.append(jumpIfNoAvailableInput(countToCheckForNextAlternative - countCheckedForCurrentAlternative)); - } else { // CASE 3: Both alternatives are the same length. - ASSERT(countCheckedForCurrentAlternative == countToCheckForNextAlternative); - - // If the next alterative is the same length as this one, then no need to check the input - - // if there was sufficent input to run the current alternative then there is sufficient - // input to run the next one; if not, there isn't. - state.linkAlternativeBacktracks(this); - } - state.checkedTotal -= countCheckedForCurrentAlternative; - countCheckedForCurrentAlternative = countToCheckForNextAlternative; - state.checkedTotal += countCheckedForCurrentAlternative; - } + default: + m_ops.append(term); } } + } - // If we get here, all Alternatives failed... + // 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; - state.checkedTotal -= countCheckedForCurrentAlternative; + // Emit the 'once through' alternatives. + if (alternatives.size() && alternatives[0]->onceThrough()) { + m_ops.append(YarrOp(OpBodyAlternativeBegin)); + m_ops.last().m_previousOp = notFound; - if (!setRepeatAlternativeLabels) { - // If there are no alternatives that need repeating (all are marked 'onceThrough') then just link - // the match failures to this point, and fall through to the return below. - state.linkAlternativeBacktracks(this, true); + do { + size_t lastOpIndex = m_ops.size() - 1; + PatternAlternative* alternative = alternatives[currentAlternativeIndex]; + opCompileAlternative(alternative); - notEnoughInputForPreviousAlternative.link(this); - } else { - // How much more input need there be to be able to retry from the first alternative? - // examples: - // /yarr_jit/ or /wrec|pcre/ - // In these examples we need check for one more input before looping. - // /yarr_jit|pcre/ - // In this case we need check for 5 more input to loop (+4 to allow for the first alterative - // being four longer than the last alternative checked, and another +1 to effectively move - // the start position along by one). - // /yarr|rules/ or /wrec|notsomuch/ - // In these examples, provided that there was sufficient input to have just been matching for - // the second alternative we can loop without checking for available input (since the second - // alternative is longer than the first). In the latter example we need to decrement index - // (by 4) so the start position is only progressed by 1 from the last iteration. - int incrementForNextIter = (countToCheckForFirstAlternative - countCheckedForCurrentAlternative) + 1; - - // First, deal with the cases where there was sufficient input to try the last alternative. - if (incrementForNextIter > 0) // We need to check for more input anyway, fall through to the checking below. - state.linkAlternativeBacktracks(this, true); - else if (m_pattern.m_body->m_hasFixedSize && !incrementForNextIter) // No need to update anything, link these backtracks straight to the to pof the loop! - state.linkAlternativeBacktracksTo(this, firstAlternativeInputChecked, true); - else { // no need to check the input, but we do have some bookkeeping to do first. - state.linkAlternativeBacktracks(this, true); - - // Where necessary update our preserved start position. - if (!m_pattern.m_body->m_hasFixedSize) { - move(index, regT0); - sub32(Imm32(countCheckedForCurrentAlternative - 1), regT0); - store32(regT0, Address(output)); - } + size_t thisOpIndex = m_ops.size(); + m_ops.append(YarrOp(OpBodyAlternativeNext)); - // Update index if necessary, and loop (without checking). - if (incrementForNextIter) - add32(Imm32(incrementForNextIter), index); - jump().linkTo(firstAlternativeInputChecked, this); - } + YarrOp& lastOp = m_ops[lastOpIndex]; + YarrOp& thisOp = m_ops[thisOpIndex]; - notEnoughInputForPreviousAlternative.link(this); - // Update our idea of the start position, if we're tracking this. - if (!m_pattern.m_body->m_hasFixedSize) { - if (countCheckedForCurrentAlternative - 1) { - move(index, regT0); - sub32(Imm32(countCheckedForCurrentAlternative - 1), regT0); - store32(regT0, Address(output)); - } else - store32(index, Address(output)); - } + lastOp.m_alternative = alternative; + lastOp.m_nextOp = thisOpIndex; + thisOp.m_previousOp = lastOpIndex; + + ++currentAlternativeIndex; + } while (currentAlternativeIndex < alternatives.size() && alternatives[currentAlternativeIndex]->onceThrough()); - // Check if there is sufficent input to run the first alternative again. - jumpIfAvailableInput(incrementForNextIter).linkTo(firstAlternativeInputChecked, this); - // No - insufficent input to run the first alteranative, are there any other alternatives we - // might need to check? If so, the last check will have left the index incremented by - // (countToCheckForFirstAlternative + 1), so we need test whether countToCheckForFirstAlternative - // LESS input is available, to have the effect of just progressing the start position by 1 - // from the last iteration. If this check passes we can just jump up to the check associated - // with the first alternative in the loop. This is a bit sad, since we'll end up trying the - // first alternative again, and this check will fail (otherwise the check planted just above - // here would have passed). This is a bit sad, however it saves trying to do something more - // complex here in compilation, and in the common case we should end up coallescing the checks. - // - // FIXME: a nice improvement here may be to stop trying to match sooner, based on the least - // of the minimum-alternative-lengths. E.g. if I have two alternatives of length 200 and 150, - // and a string of length 100, we'll end up looping index from 0 to 100, checking whether there - // is sufficient input to run either alternative (constantly failing). If there had been only - // one alternative, or if the shorter alternative had come first, we would have terminated - // immediately. :-/ - if (hasShorterAlternatives) - jumpIfAvailableInput(-countToCheckForFirstAlternative).linkTo(firstAlternative, this); - // index will now be a bit garbled (depending on whether 'hasShorterAlternatives' is true, - // it has either been incremented by 1 or by (countToCheckForFirstAlternative + 1) ... - // but since we're about to return a failure this doesn't really matter!) + YarrOp& lastOp = m_ops.last(); + + ASSERT(lastOp.m_op == OpBodyAlternativeNext); + lastOp.m_op = OpBodyAlternativeEnd; + lastOp.m_alternative = 0; + lastOp.m_nextOp = notFound; } - if (m_pattern.m_body->m_callFrameSize) - addPtr(Imm32(m_pattern.m_body->m_callFrameSize * sizeof(void*)), stackPointerRegister); + if (currentAlternativeIndex == alternatives.size()) { + m_ops.append(YarrOp(OpMatchFailed)); + return; + } - move(TrustedImm32(-1), returnRegister); + // 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)); - generateReturn(); + YarrOp& lastOp = m_ops[lastOpIndex]; + YarrOp& thisOp = m_ops[thisOpIndex]; - m_expressionState.emitParenthesesTail(this); - m_expressionState.emitIndirectJumpTable(this); - m_expressionState.linkToNextIteration(this); + 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() @@ -2230,10 +2325,11 @@ public: YarrGenerator(YarrPattern& pattern) : m_pattern(pattern) , m_shouldFallBack(false) + , m_checked(0) { } - void generate() + void compile(JSGlobalData* globalData, YarrCodeBlock& jitObject) { generateEnter(); @@ -2243,26 +2339,50 @@ public: if (m_pattern.m_body->m_callFrameSize) subPtr(Imm32(m_pattern.m_body->m_callFrameSize * sizeof(void*)), stackPointerRegister); - generateDisjunction(m_pattern.m_body); - } - - void compile(JSGlobalData* globalData, YarrCodeBlock& jitObject) - { - generate(); + // Compile the pattern to the internal 'YarrOp' representation. + opCompileBody(m_pattern.m_body); - LinkBuffer patchBuffer(this, globalData->regexAllocator); + // 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; + } - for (unsigned i = 0; i < m_expressionState.m_backtrackRecords.size(); ++i) - patchBuffer.patch(m_expressionState.m_backtrackRecords[i].dataLabel, patchBuffer.locationOf(m_expressionState.m_backtrackRecords[i].backtrackLocation)); + generate(); + backtrack(); - jitObject.set(patchBuffer.finalizeCode()); + // Link & finalize the code. + LinkBuffer linkBuffer(this, globalData->regexAllocator); + m_backtrackingState.linkDataLabels(linkBuffer); + jitObject.set(linkBuffer.finalizeCode()); jitObject.setFallBack(m_shouldFallBack); } private: YarrPattern& m_pattern; + + // 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; - GenerationState m_expressionState; + + // 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, JSGlobalData* globalData, YarrCodeBlock& jitObject) |