Home | History | Annotate | Download | only in jit
      1 /*
      2  * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 
     28 #if ENABLE(JIT)
     29 #include "JIT.h"
     30 
     31 // This probably does not belong here; adding here for now as a quick Windows build fix.
     32 #if ENABLE(ASSEMBLER) && CPU(X86) && !OS(MAC_OS_X)
     33 #include "MacroAssembler.h"
     34 JSC::MacroAssemblerX86Common::SSE2CheckState JSC::MacroAssemblerX86Common::s_sse2CheckState = NotCheckedSSE2;
     35 #endif
     36 
     37 #include "CodeBlock.h"
     38 #include "Interpreter.h"
     39 #include "JITInlineMethods.h"
     40 #include "JITStubCall.h"
     41 #include "JSArray.h"
     42 #include "JSFunction.h"
     43 #include "LinkBuffer.h"
     44 #include "RepatchBuffer.h"
     45 #include "ResultType.h"
     46 #include "SamplingTool.h"
     47 #include "dfg/DFGNode.h" // for DFG_SUCCESS_STATS
     48 
     49 using namespace std;
     50 
     51 namespace JSC {
     52 
     53 void ctiPatchNearCallByReturnAddress(CodeBlock* codeblock, ReturnAddressPtr returnAddress, MacroAssemblerCodePtr newCalleeFunction)
     54 {
     55     RepatchBuffer repatchBuffer(codeblock);
     56     repatchBuffer.relinkNearCallerToTrampoline(returnAddress, newCalleeFunction);
     57 }
     58 
     59 void ctiPatchCallByReturnAddress(CodeBlock* codeblock, ReturnAddressPtr returnAddress, MacroAssemblerCodePtr newCalleeFunction)
     60 {
     61     RepatchBuffer repatchBuffer(codeblock);
     62     repatchBuffer.relinkCallerToTrampoline(returnAddress, newCalleeFunction);
     63 }
     64 
     65 void ctiPatchCallByReturnAddress(CodeBlock* codeblock, ReturnAddressPtr returnAddress, FunctionPtr newCalleeFunction)
     66 {
     67     RepatchBuffer repatchBuffer(codeblock);
     68     repatchBuffer.relinkCallerToFunction(returnAddress, newCalleeFunction);
     69 }
     70 
     71 JIT::JIT(JSGlobalData* globalData, CodeBlock* codeBlock, void* linkerOffset)
     72     : m_interpreter(globalData->interpreter)
     73     , m_globalData(globalData)
     74     , m_codeBlock(codeBlock)
     75     , m_labels(codeBlock ? codeBlock->instructions().size() : 0)
     76     , m_propertyAccessCompilationInfo(codeBlock ? codeBlock->numberOfStructureStubInfos() : 0)
     77     , m_callStructureStubCompilationInfo(codeBlock ? codeBlock->numberOfCallLinkInfos() : 0)
     78     , m_bytecodeOffset((unsigned)-1)
     79 #if USE(JSVALUE32_64)
     80     , m_jumpTargetIndex(0)
     81     , m_mappedBytecodeOffset((unsigned)-1)
     82     , m_mappedVirtualRegisterIndex((unsigned)-1)
     83     , m_mappedTag((RegisterID)-1)
     84     , m_mappedPayload((RegisterID)-1)
     85 #else
     86     , m_lastResultBytecodeRegister(std::numeric_limits<int>::max())
     87     , m_jumpTargetsPosition(0)
     88 #endif
     89     , m_linkerOffset(linkerOffset)
     90 {
     91 }
     92 
     93 #if USE(JSVALUE32_64)
     94 void JIT::emitTimeoutCheck()
     95 {
     96     Jump skipTimeout = branchSub32(NonZero, TrustedImm32(1), timeoutCheckRegister);
     97     JITStubCall stubCall(this, cti_timeout_check);
     98     stubCall.addArgument(regT1, regT0); // save last result registers.
     99     stubCall.call(timeoutCheckRegister);
    100     stubCall.getArgument(0, regT1, regT0); // reload last result registers.
    101     skipTimeout.link(this);
    102 }
    103 #else
    104 void JIT::emitTimeoutCheck()
    105 {
    106     Jump skipTimeout = branchSub32(NonZero, TrustedImm32(1), timeoutCheckRegister);
    107     JITStubCall(this, cti_timeout_check).call(timeoutCheckRegister);
    108     skipTimeout.link(this);
    109 
    110     killLastResultRegister();
    111 }
    112 #endif
    113 
    114 #define NEXT_OPCODE(name) \
    115     m_bytecodeOffset += OPCODE_LENGTH(name); \
    116     break;
    117 
    118 #if USE(JSVALUE32_64)
    119 #define DEFINE_BINARY_OP(name) \
    120     case name: { \
    121         JITStubCall stubCall(this, cti_##name); \
    122         stubCall.addArgument(currentInstruction[2].u.operand); \
    123         stubCall.addArgument(currentInstruction[3].u.operand); \
    124         stubCall.call(currentInstruction[1].u.operand); \
    125         NEXT_OPCODE(name); \
    126     }
    127 
    128 #define DEFINE_UNARY_OP(name) \
    129     case name: { \
    130         JITStubCall stubCall(this, cti_##name); \
    131         stubCall.addArgument(currentInstruction[2].u.operand); \
    132         stubCall.call(currentInstruction[1].u.operand); \
    133         NEXT_OPCODE(name); \
    134     }
    135 
    136 #else // USE(JSVALUE32_64)
    137 
    138 #define DEFINE_BINARY_OP(name) \
    139     case name: { \
    140         JITStubCall stubCall(this, cti_##name); \
    141         stubCall.addArgument(currentInstruction[2].u.operand, regT2); \
    142         stubCall.addArgument(currentInstruction[3].u.operand, regT2); \
    143         stubCall.call(currentInstruction[1].u.operand); \
    144         NEXT_OPCODE(name); \
    145     }
    146 
    147 #define DEFINE_UNARY_OP(name) \
    148     case name: { \
    149         JITStubCall stubCall(this, cti_##name); \
    150         stubCall.addArgument(currentInstruction[2].u.operand, regT2); \
    151         stubCall.call(currentInstruction[1].u.operand); \
    152         NEXT_OPCODE(name); \
    153     }
    154 #endif // USE(JSVALUE32_64)
    155 
    156 #define DEFINE_OP(name) \
    157     case name: { \
    158         emit_##name(currentInstruction); \
    159         NEXT_OPCODE(name); \
    160     }
    161 
    162 #define DEFINE_SLOWCASE_OP(name) \
    163     case name: { \
    164         emitSlow_##name(currentInstruction, iter); \
    165         NEXT_OPCODE(name); \
    166     }
    167 
    168 void JIT::privateCompileMainPass()
    169 {
    170     Instruction* instructionsBegin = m_codeBlock->instructions().begin();
    171     unsigned instructionCount = m_codeBlock->instructions().size();
    172 
    173     m_propertyAccessInstructionIndex = 0;
    174     m_globalResolveInfoIndex = 0;
    175     m_callLinkInfoIndex = 0;
    176 
    177     for (m_bytecodeOffset = 0; m_bytecodeOffset < instructionCount; ) {
    178         Instruction* currentInstruction = instructionsBegin + m_bytecodeOffset;
    179         ASSERT_WITH_MESSAGE(m_interpreter->isOpcode(currentInstruction->u.opcode), "privateCompileMainPass gone bad @ %d", m_bytecodeOffset);
    180 
    181 #if ENABLE(OPCODE_SAMPLING)
    182         if (m_bytecodeOffset > 0) // Avoid the overhead of sampling op_enter twice.
    183             sampleInstruction(currentInstruction);
    184 #endif
    185 
    186 #if USE(JSVALUE64)
    187         if (m_labels[m_bytecodeOffset].isUsed())
    188             killLastResultRegister();
    189 #endif
    190 
    191         m_labels[m_bytecodeOffset] = label();
    192 
    193         switch (m_interpreter->getOpcodeID(currentInstruction->u.opcode)) {
    194         DEFINE_BINARY_OP(op_del_by_val)
    195         DEFINE_BINARY_OP(op_in)
    196         DEFINE_BINARY_OP(op_less)
    197         DEFINE_BINARY_OP(op_lesseq)
    198         DEFINE_UNARY_OP(op_is_boolean)
    199         DEFINE_UNARY_OP(op_is_function)
    200         DEFINE_UNARY_OP(op_is_number)
    201         DEFINE_UNARY_OP(op_is_object)
    202         DEFINE_UNARY_OP(op_is_string)
    203         DEFINE_UNARY_OP(op_is_undefined)
    204 #if USE(JSVALUE64)
    205         DEFINE_UNARY_OP(op_negate)
    206 #endif
    207         DEFINE_UNARY_OP(op_typeof)
    208 
    209         DEFINE_OP(op_add)
    210         DEFINE_OP(op_bitand)
    211         DEFINE_OP(op_bitnot)
    212         DEFINE_OP(op_bitor)
    213         DEFINE_OP(op_bitxor)
    214         DEFINE_OP(op_call)
    215         DEFINE_OP(op_call_eval)
    216         DEFINE_OP(op_call_varargs)
    217         DEFINE_OP(op_catch)
    218         DEFINE_OP(op_construct)
    219         DEFINE_OP(op_get_callee)
    220         DEFINE_OP(op_create_this)
    221         DEFINE_OP(op_convert_this)
    222         DEFINE_OP(op_convert_this_strict)
    223         DEFINE_OP(op_init_lazy_reg)
    224         DEFINE_OP(op_create_arguments)
    225         DEFINE_OP(op_debug)
    226         DEFINE_OP(op_del_by_id)
    227         DEFINE_OP(op_div)
    228         DEFINE_OP(op_end)
    229         DEFINE_OP(op_enter)
    230         DEFINE_OP(op_create_activation)
    231         DEFINE_OP(op_eq)
    232         DEFINE_OP(op_eq_null)
    233         DEFINE_OP(op_get_by_id)
    234         DEFINE_OP(op_get_arguments_length)
    235         DEFINE_OP(op_get_by_val)
    236         DEFINE_OP(op_get_argument_by_val)
    237         DEFINE_OP(op_get_by_pname)
    238         DEFINE_OP(op_get_global_var)
    239         DEFINE_OP(op_get_pnames)
    240         DEFINE_OP(op_get_scoped_var)
    241         DEFINE_OP(op_check_has_instance)
    242         DEFINE_OP(op_instanceof)
    243         DEFINE_OP(op_jeq_null)
    244         DEFINE_OP(op_jfalse)
    245         DEFINE_OP(op_jmp)
    246         DEFINE_OP(op_jmp_scopes)
    247         DEFINE_OP(op_jneq_null)
    248         DEFINE_OP(op_jneq_ptr)
    249         DEFINE_OP(op_jnless)
    250         DEFINE_OP(op_jless)
    251         DEFINE_OP(op_jlesseq)
    252         DEFINE_OP(op_jnlesseq)
    253         DEFINE_OP(op_jsr)
    254         DEFINE_OP(op_jtrue)
    255         DEFINE_OP(op_load_varargs)
    256         DEFINE_OP(op_loop)
    257         DEFINE_OP(op_loop_if_less)
    258         DEFINE_OP(op_loop_if_lesseq)
    259         DEFINE_OP(op_loop_if_true)
    260         DEFINE_OP(op_loop_if_false)
    261         DEFINE_OP(op_lshift)
    262         DEFINE_OP(op_method_check)
    263         DEFINE_OP(op_mod)
    264         DEFINE_OP(op_mov)
    265         DEFINE_OP(op_mul)
    266 #if USE(JSVALUE32_64)
    267         DEFINE_OP(op_negate)
    268 #endif
    269         DEFINE_OP(op_neq)
    270         DEFINE_OP(op_neq_null)
    271         DEFINE_OP(op_new_array)
    272         DEFINE_OP(op_new_func)
    273         DEFINE_OP(op_new_func_exp)
    274         DEFINE_OP(op_new_object)
    275         DEFINE_OP(op_new_regexp)
    276         DEFINE_OP(op_next_pname)
    277         DEFINE_OP(op_not)
    278         DEFINE_OP(op_nstricteq)
    279         DEFINE_OP(op_pop_scope)
    280         DEFINE_OP(op_post_dec)
    281         DEFINE_OP(op_post_inc)
    282         DEFINE_OP(op_pre_dec)
    283         DEFINE_OP(op_pre_inc)
    284         DEFINE_OP(op_profile_did_call)
    285         DEFINE_OP(op_profile_will_call)
    286         DEFINE_OP(op_push_new_scope)
    287         DEFINE_OP(op_push_scope)
    288         DEFINE_OP(op_put_by_id)
    289         DEFINE_OP(op_put_by_index)
    290         DEFINE_OP(op_put_by_val)
    291         DEFINE_OP(op_put_getter)
    292         DEFINE_OP(op_put_global_var)
    293         DEFINE_OP(op_put_scoped_var)
    294         DEFINE_OP(op_put_setter)
    295         DEFINE_OP(op_resolve)
    296         DEFINE_OP(op_resolve_base)
    297         DEFINE_OP(op_ensure_property_exists)
    298         DEFINE_OP(op_resolve_global)
    299         DEFINE_OP(op_resolve_global_dynamic)
    300         DEFINE_OP(op_resolve_skip)
    301         DEFINE_OP(op_resolve_with_base)
    302         DEFINE_OP(op_ret)
    303         DEFINE_OP(op_call_put_result)
    304         DEFINE_OP(op_ret_object_or_this)
    305         DEFINE_OP(op_rshift)
    306         DEFINE_OP(op_urshift)
    307         DEFINE_OP(op_sret)
    308         DEFINE_OP(op_strcat)
    309         DEFINE_OP(op_stricteq)
    310         DEFINE_OP(op_sub)
    311         DEFINE_OP(op_switch_char)
    312         DEFINE_OP(op_switch_imm)
    313         DEFINE_OP(op_switch_string)
    314         DEFINE_OP(op_tear_off_activation)
    315         DEFINE_OP(op_tear_off_arguments)
    316         DEFINE_OP(op_throw)
    317         DEFINE_OP(op_throw_reference_error)
    318         DEFINE_OP(op_to_jsnumber)
    319         DEFINE_OP(op_to_primitive)
    320 
    321         case op_get_array_length:
    322         case op_get_by_id_chain:
    323         case op_get_by_id_generic:
    324         case op_get_by_id_proto:
    325         case op_get_by_id_proto_list:
    326         case op_get_by_id_self:
    327         case op_get_by_id_self_list:
    328         case op_get_by_id_getter_chain:
    329         case op_get_by_id_getter_proto:
    330         case op_get_by_id_getter_proto_list:
    331         case op_get_by_id_getter_self:
    332         case op_get_by_id_getter_self_list:
    333         case op_get_by_id_custom_chain:
    334         case op_get_by_id_custom_proto:
    335         case op_get_by_id_custom_proto_list:
    336         case op_get_by_id_custom_self:
    337         case op_get_by_id_custom_self_list:
    338         case op_get_string_length:
    339         case op_put_by_id_generic:
    340         case op_put_by_id_replace:
    341         case op_put_by_id_transition:
    342             ASSERT_NOT_REACHED();
    343         }
    344     }
    345 
    346     ASSERT(m_propertyAccessInstructionIndex == m_codeBlock->numberOfStructureStubInfos());
    347     ASSERT(m_callLinkInfoIndex == m_codeBlock->numberOfCallLinkInfos());
    348 
    349 #ifndef NDEBUG
    350     // Reset this, in order to guard its use with ASSERTs.
    351     m_bytecodeOffset = (unsigned)-1;
    352 #endif
    353 }
    354 
    355 
    356 void JIT::privateCompileLinkPass()
    357 {
    358     unsigned jmpTableCount = m_jmpTable.size();
    359     for (unsigned i = 0; i < jmpTableCount; ++i)
    360         m_jmpTable[i].from.linkTo(m_labels[m_jmpTable[i].toBytecodeOffset], this);
    361     m_jmpTable.clear();
    362 }
    363 
    364 void JIT::privateCompileSlowCases()
    365 {
    366     Instruction* instructionsBegin = m_codeBlock->instructions().begin();
    367 
    368     m_propertyAccessInstructionIndex = 0;
    369     m_globalResolveInfoIndex = 0;
    370     m_callLinkInfoIndex = 0;
    371 
    372     for (Vector<SlowCaseEntry>::iterator iter = m_slowCases.begin(); iter != m_slowCases.end();) {
    373 #if USE(JSVALUE64)
    374         killLastResultRegister();
    375 #endif
    376 
    377         m_bytecodeOffset = iter->to;
    378 #ifndef NDEBUG
    379         unsigned firstTo = m_bytecodeOffset;
    380 #endif
    381         Instruction* currentInstruction = instructionsBegin + m_bytecodeOffset;
    382 
    383         switch (m_interpreter->getOpcodeID(currentInstruction->u.opcode)) {
    384         DEFINE_SLOWCASE_OP(op_add)
    385         DEFINE_SLOWCASE_OP(op_bitand)
    386         DEFINE_SLOWCASE_OP(op_bitnot)
    387         DEFINE_SLOWCASE_OP(op_bitor)
    388         DEFINE_SLOWCASE_OP(op_bitxor)
    389         DEFINE_SLOWCASE_OP(op_call)
    390         DEFINE_SLOWCASE_OP(op_call_eval)
    391         DEFINE_SLOWCASE_OP(op_call_varargs)
    392         DEFINE_SLOWCASE_OP(op_construct)
    393         DEFINE_SLOWCASE_OP(op_convert_this)
    394         DEFINE_SLOWCASE_OP(op_convert_this_strict)
    395         DEFINE_SLOWCASE_OP(op_div)
    396         DEFINE_SLOWCASE_OP(op_eq)
    397         DEFINE_SLOWCASE_OP(op_get_by_id)
    398         DEFINE_SLOWCASE_OP(op_get_arguments_length)
    399         DEFINE_SLOWCASE_OP(op_get_by_val)
    400         DEFINE_SLOWCASE_OP(op_get_argument_by_val)
    401         DEFINE_SLOWCASE_OP(op_get_by_pname)
    402         DEFINE_SLOWCASE_OP(op_check_has_instance)
    403         DEFINE_SLOWCASE_OP(op_instanceof)
    404         DEFINE_SLOWCASE_OP(op_jfalse)
    405         DEFINE_SLOWCASE_OP(op_jnless)
    406         DEFINE_SLOWCASE_OP(op_jless)
    407         DEFINE_SLOWCASE_OP(op_jlesseq)
    408         DEFINE_SLOWCASE_OP(op_jnlesseq)
    409         DEFINE_SLOWCASE_OP(op_jtrue)
    410         DEFINE_SLOWCASE_OP(op_load_varargs)
    411         DEFINE_SLOWCASE_OP(op_loop_if_less)
    412         DEFINE_SLOWCASE_OP(op_loop_if_lesseq)
    413         DEFINE_SLOWCASE_OP(op_loop_if_true)
    414         DEFINE_SLOWCASE_OP(op_loop_if_false)
    415         DEFINE_SLOWCASE_OP(op_lshift)
    416         DEFINE_SLOWCASE_OP(op_method_check)
    417         DEFINE_SLOWCASE_OP(op_mod)
    418         DEFINE_SLOWCASE_OP(op_mul)
    419 #if USE(JSVALUE32_64)
    420         DEFINE_SLOWCASE_OP(op_negate)
    421 #endif
    422         DEFINE_SLOWCASE_OP(op_neq)
    423         DEFINE_SLOWCASE_OP(op_not)
    424         DEFINE_SLOWCASE_OP(op_nstricteq)
    425         DEFINE_SLOWCASE_OP(op_post_dec)
    426         DEFINE_SLOWCASE_OP(op_post_inc)
    427         DEFINE_SLOWCASE_OP(op_pre_dec)
    428         DEFINE_SLOWCASE_OP(op_pre_inc)
    429         DEFINE_SLOWCASE_OP(op_put_by_id)
    430         DEFINE_SLOWCASE_OP(op_put_by_val)
    431         DEFINE_SLOWCASE_OP(op_resolve_global)
    432         DEFINE_SLOWCASE_OP(op_resolve_global_dynamic)
    433         DEFINE_SLOWCASE_OP(op_rshift)
    434         DEFINE_SLOWCASE_OP(op_urshift)
    435         DEFINE_SLOWCASE_OP(op_stricteq)
    436         DEFINE_SLOWCASE_OP(op_sub)
    437         DEFINE_SLOWCASE_OP(op_to_jsnumber)
    438         DEFINE_SLOWCASE_OP(op_to_primitive)
    439         default:
    440             ASSERT_NOT_REACHED();
    441         }
    442 
    443         ASSERT_WITH_MESSAGE(iter == m_slowCases.end() || firstTo != iter->to,"Not enough jumps linked in slow case codegen.");
    444         ASSERT_WITH_MESSAGE(firstTo == (iter - 1)->to, "Too many jumps linked in slow case codegen.");
    445 
    446         emitJumpSlowToHot(jump(), 0);
    447     }
    448 
    449 #if ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)
    450     ASSERT(m_propertyAccessInstructionIndex == m_codeBlock->numberOfStructureStubInfos());
    451 #endif
    452     ASSERT(m_callLinkInfoIndex == m_codeBlock->numberOfCallLinkInfos());
    453 
    454 #ifndef NDEBUG
    455     // Reset this, in order to guard its use with ASSERTs.
    456     m_bytecodeOffset = (unsigned)-1;
    457 #endif
    458 }
    459 
    460 JITCode JIT::privateCompile(CodePtr* functionEntryArityCheck)
    461 {
    462     // Could use a pop_m, but would need to offset the following instruction if so.
    463     preserveReturnAddressAfterCall(regT2);
    464     emitPutToCallFrameHeader(regT2, RegisterFile::ReturnPC);
    465 
    466     Label beginLabel(this);
    467 
    468     sampleCodeBlock(m_codeBlock);
    469 #if ENABLE(OPCODE_SAMPLING)
    470     sampleInstruction(m_codeBlock->instructions().begin());
    471 #endif
    472 
    473     Jump registerFileCheck;
    474     if (m_codeBlock->codeType() == FunctionCode) {
    475 #if DFG_SUCCESS_STATS
    476         static SamplingCounter counter("orignalJIT");
    477         emitCount(counter);
    478 #endif
    479 
    480         // In the case of a fast linked call, we do not set this up in the caller.
    481         emitPutImmediateToCallFrameHeader(m_codeBlock, RegisterFile::CodeBlock);
    482 
    483         addPtr(Imm32(m_codeBlock->m_numCalleeRegisters * sizeof(Register)), callFrameRegister, regT1);
    484         registerFileCheck = branchPtr(Below, AbsoluteAddress(m_globalData->interpreter->registerFile().addressOfEnd()), regT1);
    485     }
    486 
    487     Label functionBody = label();
    488 
    489     privateCompileMainPass();
    490     privateCompileLinkPass();
    491     privateCompileSlowCases();
    492 
    493     Label arityCheck;
    494     if (m_codeBlock->codeType() == FunctionCode) {
    495         registerFileCheck.link(this);
    496         m_bytecodeOffset = 0;
    497         JITStubCall(this, cti_register_file_check).call();
    498 #ifndef NDEBUG
    499         m_bytecodeOffset = (unsigned)-1; // Reset this, in order to guard its use with ASSERTs.
    500 #endif
    501         jump(functionBody);
    502 
    503         arityCheck = label();
    504         preserveReturnAddressAfterCall(regT2);
    505         emitPutToCallFrameHeader(regT2, RegisterFile::ReturnPC);
    506         branch32(Equal, regT1, TrustedImm32(m_codeBlock->m_numParameters)).linkTo(beginLabel, this);
    507         restoreArgumentReference();
    508 
    509         JITStubCall(this, m_codeBlock->m_isConstructor ? cti_op_construct_arityCheck : cti_op_call_arityCheck).call(callFrameRegister);
    510 
    511         jump(beginLabel);
    512     }
    513 
    514     ASSERT(m_jmpTable.isEmpty());
    515 
    516     LinkBuffer patchBuffer(this, m_globalData->executableAllocator.poolForSize(m_assembler.size()), m_linkerOffset);
    517 
    518     // Translate vPC offsets into addresses in JIT generated code, for switch tables.
    519     for (unsigned i = 0; i < m_switches.size(); ++i) {
    520         SwitchRecord record = m_switches[i];
    521         unsigned bytecodeOffset = record.bytecodeOffset;
    522 
    523         if (record.type != SwitchRecord::String) {
    524             ASSERT(record.type == SwitchRecord::Immediate || record.type == SwitchRecord::Character);
    525             ASSERT(record.jumpTable.simpleJumpTable->branchOffsets.size() == record.jumpTable.simpleJumpTable->ctiOffsets.size());
    526 
    527             record.jumpTable.simpleJumpTable->ctiDefault = patchBuffer.locationOf(m_labels[bytecodeOffset + record.defaultOffset]);
    528 
    529             for (unsigned j = 0; j < record.jumpTable.simpleJumpTable->branchOffsets.size(); ++j) {
    530                 unsigned offset = record.jumpTable.simpleJumpTable->branchOffsets[j];
    531                 record.jumpTable.simpleJumpTable->ctiOffsets[j] = offset ? patchBuffer.locationOf(m_labels[bytecodeOffset + offset]) : record.jumpTable.simpleJumpTable->ctiDefault;
    532             }
    533         } else {
    534             ASSERT(record.type == SwitchRecord::String);
    535 
    536             record.jumpTable.stringJumpTable->ctiDefault = patchBuffer.locationOf(m_labels[bytecodeOffset + record.defaultOffset]);
    537 
    538             StringJumpTable::StringOffsetTable::iterator end = record.jumpTable.stringJumpTable->offsetTable.end();
    539             for (StringJumpTable::StringOffsetTable::iterator it = record.jumpTable.stringJumpTable->offsetTable.begin(); it != end; ++it) {
    540                 unsigned offset = it->second.branchOffset;
    541                 it->second.ctiOffset = offset ? patchBuffer.locationOf(m_labels[bytecodeOffset + offset]) : record.jumpTable.stringJumpTable->ctiDefault;
    542             }
    543         }
    544     }
    545 
    546     for (size_t i = 0; i < m_codeBlock->numberOfExceptionHandlers(); ++i) {
    547         HandlerInfo& handler = m_codeBlock->exceptionHandler(i);
    548         handler.nativeCode = patchBuffer.locationOf(m_labels[handler.target]);
    549     }
    550 
    551     for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter) {
    552         if (iter->to)
    553             patchBuffer.link(iter->from, FunctionPtr(iter->to));
    554     }
    555 
    556     if (m_codeBlock->needsCallReturnIndices()) {
    557         m_codeBlock->callReturnIndexVector().reserveCapacity(m_calls.size());
    558         for (Vector<CallRecord>::iterator iter = m_calls.begin(); iter != m_calls.end(); ++iter)
    559             m_codeBlock->callReturnIndexVector().append(CallReturnOffsetToBytecodeOffset(patchBuffer.returnAddressOffset(iter->from), iter->bytecodeOffset));
    560     }
    561 
    562     // Link absolute addresses for jsr
    563     for (Vector<JSRInfo>::iterator iter = m_jsrSites.begin(); iter != m_jsrSites.end(); ++iter)
    564         patchBuffer.patch(iter->storeLocation, patchBuffer.locationOf(iter->target).executableAddress());
    565 
    566 #if ENABLE(JIT_OPTIMIZE_PROPERTY_ACCESS)
    567     for (unsigned i = 0; i < m_codeBlock->numberOfStructureStubInfos(); ++i) {
    568         StructureStubInfo& info = m_codeBlock->structureStubInfo(i);
    569         info.callReturnLocation = patchBuffer.locationOf(m_propertyAccessCompilationInfo[i].callReturnLocation);
    570         info.hotPathBegin = patchBuffer.locationOf(m_propertyAccessCompilationInfo[i].hotPathBegin);
    571     }
    572 #endif
    573 #if ENABLE(JIT_OPTIMIZE_CALL)
    574     for (unsigned i = 0; i < m_codeBlock->numberOfCallLinkInfos(); ++i) {
    575         CallLinkInfo& info = m_codeBlock->callLinkInfo(i);
    576         info.callReturnLocation = patchBuffer.locationOfNearCall(m_callStructureStubCompilationInfo[i].callReturnLocation);
    577         info.hotPathBegin = patchBuffer.locationOf(m_callStructureStubCompilationInfo[i].hotPathBegin);
    578         info.hotPathOther = patchBuffer.locationOfNearCall(m_callStructureStubCompilationInfo[i].hotPathOther);
    579     }
    580 #endif
    581     unsigned methodCallCount = m_methodCallCompilationInfo.size();
    582     m_codeBlock->addMethodCallLinkInfos(methodCallCount);
    583     for (unsigned i = 0; i < methodCallCount; ++i) {
    584         MethodCallLinkInfo& info = m_codeBlock->methodCallLinkInfo(i);
    585         info.structureLabel = patchBuffer.locationOf(m_methodCallCompilationInfo[i].structureToCompare);
    586         info.callReturnLocation = m_codeBlock->structureStubInfo(m_methodCallCompilationInfo[i].propertyAccessIndex).callReturnLocation;
    587     }
    588 
    589     if (m_codeBlock->codeType() == FunctionCode && functionEntryArityCheck)
    590         *functionEntryArityCheck = patchBuffer.locationOf(arityCheck);
    591 
    592     return patchBuffer.finalizeCode();
    593 }
    594 
    595 #if ENABLE(JIT_OPTIMIZE_CALL)
    596 
    597 void JIT::linkCall(JSFunction* callee, CodeBlock* callerCodeBlock, CodeBlock* calleeCodeBlock, JIT::CodePtr code, CallLinkInfo* callLinkInfo, int callerArgCount, JSGlobalData* globalData)
    598 {
    599     RepatchBuffer repatchBuffer(callerCodeBlock);
    600 
    601     // Currently we only link calls with the exact number of arguments.
    602     // If this is a native call calleeCodeBlock is null so the number of parameters is unimportant
    603     if (!calleeCodeBlock || (callerArgCount == calleeCodeBlock->m_numParameters)) {
    604         ASSERT(!callLinkInfo->isLinked());
    605         callLinkInfo->callee.set(*globalData, callerCodeBlock->ownerExecutable(), callee);
    606         repatchBuffer.repatch(callLinkInfo->hotPathBegin, callee);
    607         repatchBuffer.relink(callLinkInfo->hotPathOther, code);
    608     }
    609 
    610     // patch the call so we do not continue to try to link.
    611     repatchBuffer.relink(callLinkInfo->callReturnLocation, globalData->jitStubs->ctiVirtualCall());
    612 }
    613 
    614 void JIT::linkConstruct(JSFunction* callee, CodeBlock* callerCodeBlock, CodeBlock* calleeCodeBlock, JIT::CodePtr code, CallLinkInfo* callLinkInfo, int callerArgCount, JSGlobalData* globalData)
    615 {
    616     RepatchBuffer repatchBuffer(callerCodeBlock);
    617 
    618     // Currently we only link calls with the exact number of arguments.
    619     // If this is a native call calleeCodeBlock is null so the number of parameters is unimportant
    620     if (!calleeCodeBlock || (callerArgCount == calleeCodeBlock->m_numParameters)) {
    621         ASSERT(!callLinkInfo->isLinked());
    622         callLinkInfo->callee.set(*globalData, callerCodeBlock->ownerExecutable(), callee);
    623         repatchBuffer.repatch(callLinkInfo->hotPathBegin, callee);
    624         repatchBuffer.relink(callLinkInfo->hotPathOther, code);
    625     }
    626 
    627     // patch the call so we do not continue to try to link.
    628     repatchBuffer.relink(callLinkInfo->callReturnLocation, globalData->jitStubs->ctiVirtualConstruct());
    629 }
    630 #endif // ENABLE(JIT_OPTIMIZE_CALL)
    631 
    632 } // namespace JSC
    633 
    634 #endif // ENABLE(JIT)
    635