Example #1
0
void JITCompiler::compileEntry()
{
    // This code currently matches the old JIT. In the function header we need to
    // save return address and call frame via the prologue and perform a fast stack check.
    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=56292
    // We'll need to convert the remaining cti_ style calls (specifically the stack
    // check) which will be dependent on stack layout. (We'd need to account for this in
    // both normal return code and when jumping to an exception handler).
    emitFunctionPrologue();
    emitPutImmediateToCallFrameHeader(m_codeBlock, JSStack::CodeBlock);
    jitAssertTagsInPlace();
}
Example #2
0
void JITCompiler::compileEntry()
{
    // This code currently matches the old JIT. In the function header we need to
    // pop the return address (since we do not allow any recursion on the machine
    // stack), and perform a fast stack check.
    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=56292
    // We'll need to convert the remaining cti_ style calls (specifically the stack
    // check) which will be dependent on stack layout. (We'd need to account for this in
    // both normal return code and when jumping to an exception handler).
    preserveReturnAddressAfterCall(GPRInfo::regT2);
    emitPutReturnPCToCallFrameHeader(GPRInfo::regT2);
    emitPutImmediateToCallFrameHeader(m_codeBlock, JSStack::CodeBlock);
}
Example #3
0
void JITCompiler::compileFunction(JITCode& entry, MacroAssemblerCodePtr& entryWithArityCheck)
{
    // === Stage 1 - Function header code generation ===
    //
    // This code currently matches the old JIT. In the function header we need to
    // pop the return address (since we do not allow any recursion on the machine
    // stack), and perform a fast register file check.

    // This is the main entry point, without performing an arity check.
    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=56292
    // We'll need to convert the remaining cti_ style calls (specifically the register file
    // check) which will be dependent on stack layout. (We'd need to account for this in
    // both normal return code and when jumping to an exception handler).
    preserveReturnAddressAfterCall(GPRInfo::regT2);
    emitPutToCallFrameHeader(GPRInfo::regT2, RegisterFile::ReturnPC);
    // If we needed to perform an arity check we will already have moved the return address,
    // so enter after this.
    Label fromArityCheck(this);

    // Setup a pointer to the codeblock in the CallFrameHeader.
    emitPutImmediateToCallFrameHeader(m_codeBlock, RegisterFile::CodeBlock);

    // Plant a check that sufficient space is available in the RegisterFile.
    // FIXME: https://bugs.webkit.org/show_bug.cgi?id=56291
    addPtr(Imm32(m_codeBlock->m_numCalleeRegisters * sizeof(Register)), GPRInfo::callFrameRegister, GPRInfo::regT1);
    Jump registerFileCheck = branchPtr(Below, AbsoluteAddress(m_globalData->interpreter->registerFile().addressOfEnd()), GPRInfo::regT1);
    // Return here after register file check.
    Label fromRegisterFileCheck = label();


    // === Stage 2 - Function body code generation ===
    //
    // We generate the speculative code path, followed by the non-speculative
    // code for the function. Next we need to link the two together, making
    // bail-outs from the speculative path jump to the corresponding point on
    // the non-speculative one (and generating any code necessary to juggle
    // register values around, rebox values, and ensure spilled, to match the
    // non-speculative path's requirements).

#if DFG_JIT_BREAK_ON_EVERY_FUNCTION
    // Handy debug tool!
    breakpoint();
#endif

    // First generate the speculative path.
    Label speculativePathBegin = label();
    SpeculativeJIT speculative(*this);
#if !DFG_DEBUG_LOCAL_DISBALE_SPECULATIVE
    bool compiledSpeculative = speculative.compile();
#else
    bool compiledSpeculative = false;
#endif

    // Next, generate the non-speculative path. We pass this a SpeculationCheckIndexIterator
    // to allow it to check which nodes in the graph may bail out, and may need to reenter the
    // non-speculative path.
    if (compiledSpeculative) {
        SpeculationCheckIndexIterator checkIterator(speculative.speculationChecks());
        NonSpeculativeJIT nonSpeculative(*this);
        nonSpeculative.compile(checkIterator);

        // Link the bail-outs from the speculative path to the corresponding entry points into the non-speculative one.
        linkSpeculationChecks(speculative, nonSpeculative);
    } else {
        // If compilation through the SpeculativeJIT failed, throw away the code we generated.
        m_calls.clear();
        rewindToLabel(speculativePathBegin);

        SpeculationCheckVector noChecks;
        SpeculationCheckIndexIterator checkIterator(noChecks);
        NonSpeculativeJIT nonSpeculative(*this);
        nonSpeculative.compile(checkIterator);
    }

    // === Stage 3 - Function footer code generation ===
    //
    // Generate code to lookup and jump to exception handlers, to perform the slow
    // register file check (if the fast one in the function header fails), and
    // generate the entry point with arity check.

    // Iterate over the m_calls vector, checking for exception checks,
    // and linking them to here.
    unsigned exceptionCheckCount = 0;
    for (unsigned i = 0; i < m_calls.size(); ++i) {
        Jump& exceptionCheck = m_calls[i].m_exceptionCheck;
        if (exceptionCheck.isSet()) {
            exceptionCheck.link(this);
            ++exceptionCheckCount;
        }
    }
    // If any exception checks were linked, generate code to lookup a handler.
    if (exceptionCheckCount) {
        // lookupExceptionHandler is passed two arguments, exec (the CallFrame*), and
        // an identifier for the operation that threw the exception, which we can use
        // to look up handler information. The identifier we use is the return address
        // of the call out from JIT code that threw the exception; this is still
        // available on the stack, just below the stack pointer!
        move(GPRInfo::callFrameRegister, GPRInfo::argumentGPR0);
        peek(GPRInfo::argumentGPR1, -1);
        m_calls.append(CallRecord(call(), lookupExceptionHandler));
        // lookupExceptionHandler leaves the handler CallFrame* in the returnValueGPR,
        // and the address of the handler in returnValueGPR2.
        jump(GPRInfo::returnValueGPR2);
    }

    // Generate the register file check; if the fast check in the function head fails,
    // we need to call out to a helper function to check whether more space is available.
    // FIXME: change this from a cti call to a DFG style operation (normal C calling conventions).
    registerFileCheck.link(this);
    move(stackPointerRegister, GPRInfo::argumentGPR0);
    poke(GPRInfo::callFrameRegister, OBJECT_OFFSETOF(struct JITStackFrame, callFrame) / sizeof(void*));
    Call callRegisterFileCheck = call();
    jump(fromRegisterFileCheck);

    // The fast entry point into a function does not check the correct number of arguments
    // have been passed to the call (we only use the fast entry point where we can statically
    // determine the correct number of arguments have been passed, or have already checked).
    // In cases where an arity check is necessary, we enter here.
    // FIXME: change this from a cti call to a DFG style operation (normal C calling conventions).
    Label arityCheck = label();
    preserveReturnAddressAfterCall(GPRInfo::regT2);
    emitPutToCallFrameHeader(GPRInfo::regT2, RegisterFile::ReturnPC);
    branch32(Equal, GPRInfo::regT1, Imm32(m_codeBlock->m_numParameters)).linkTo(fromArityCheck, this);
    move(stackPointerRegister, GPRInfo::argumentGPR0);
    poke(GPRInfo::callFrameRegister, OBJECT_OFFSETOF(struct JITStackFrame, callFrame) / sizeof(void*));
    Call callArityCheck = call();
    move(GPRInfo::regT0, GPRInfo::callFrameRegister);
    jump(fromArityCheck);


    // === Stage 4 - Link ===
    //
    // Link the code, populate data in CodeBlock data structures.

    LinkBuffer linkBuffer(*m_globalData, this, m_globalData->executableAllocator);

#if DFG_DEBUG_VERBOSE
    fprintf(stderr, "JIT code start at %p\n", linkBuffer.debugAddress());
#endif

    // Link all calls out from the JIT code to their respective functions.
    for (unsigned i = 0; i < m_calls.size(); ++i)
        linkBuffer.link(m_calls[i].m_call, m_calls[i].m_function);

    if (m_codeBlock->needsCallReturnIndices()) {
        m_codeBlock->callReturnIndexVector().reserveCapacity(exceptionCheckCount);
        for (unsigned i = 0; i < m_calls.size(); ++i) {
            if (m_calls[i].m_exceptionCheck.isSet()) {
                unsigned returnAddressOffset = linkBuffer.returnAddressOffset(m_calls[i].m_call);
                unsigned exceptionInfo = m_calls[i].m_exceptionInfo;
                m_codeBlock->callReturnIndexVector().append(CallReturnOffsetToBytecodeOffset(returnAddressOffset, exceptionInfo));
            }
        }
    }

    // FIXME: switch the register file check & arity check over to DFGOpertaion style calls, not JIT stubs.
    linkBuffer.link(callRegisterFileCheck, cti_register_file_check);
    linkBuffer.link(callArityCheck, m_codeBlock->m_isConstructor ? cti_op_construct_arityCheck : cti_op_call_arityCheck);

    entryWithArityCheck = linkBuffer.locationOf(arityCheck);
    entry = linkBuffer.finalizeCode();
}