C++ StringPrintStream::reset方法代码示例

BytecodeSequence::BytecodeSequence(CodeBlock* codeBlock)
{
    StringPrintStream out;
    
    for (unsigned i = 0; i < codeBlock->numberOfArgumentValueProfiles(); ++i) {
        ConcurrentJSLocker locker(codeBlock->m_lock);
        CString description = codeBlock->valueProfileForArgument(i)->briefDescription(locker);
        if (!description.length())
            continue;
        out.reset();
        out.print("arg", i, ": ", description);
        m_header.append(out.toCString());
    }
    
    StubInfoMap stubInfos;
    codeBlock->getStubInfoMap(stubInfos);
    
    for (unsigned bytecodeIndex = 0; bytecodeIndex < codeBlock->instructions().size();) {
        out.reset();
        codeBlock->dumpBytecode(out, bytecodeIndex, stubInfos);
        m_sequence.append(Bytecode(bytecodeIndex, codeBlock->vm()->interpreter->getOpcodeID(codeBlock->instructions()[bytecodeIndex].u.opcode), out.toCString()));
        bytecodeIndex += opcodeLength(
            codeBlock->vm()->interpreter->getOpcodeID(
                codeBlock->instructions()[bytecodeIndex].u.opcode));
    }
}

Vector<JITDisassembler::DumpedOp> JITDisassembler::dumpVectorForInstructions(LinkBuffer& linkBuffer, const char* prefix, Vector<MacroAssembler::Label>& labels, MacroAssembler::Label endLabel)
{
    StringPrintStream out;
    Vector<DumpedOp> result;
    
    for (unsigned i = 0; i < labels.size();) {
        if (!labels[i].isSet()) {
            i++;
            continue;
        }
        out.reset();
        result.append(DumpedOp());
        result.last().index = i;
        out.print(prefix);
        m_codeBlock->dumpBytecode(out, i);
        for (unsigned nextIndex = i + 1; ; nextIndex++) {
            if (nextIndex >= labels.size()) {
                dumpDisassembly(out, linkBuffer, labels[i], endLabel);
                result.last().disassembly = out.toCString();
                return result;
            }
            if (labels[nextIndex].isSet()) {
                dumpDisassembly(out, linkBuffer, labels[i], labels[nextIndex]);
                result.last().disassembly = out.toCString();
                i = nextIndex;
                break;
            }
        }
    }
    
    return result;
}

void JITDisassembler::reportToProfiler(Profiler::Compilation* compilation, LinkBuffer& linkBuffer)
{
    StringPrintStream out;
    
    dumpHeader(out, linkBuffer);
    compilation->addDescription(Profiler::CompiledBytecode(Profiler::OriginStack(), out.toCString()));
    out.reset();
    dumpDisassembly(out, linkBuffer, m_startOfCode, m_labelForBytecodeIndexInMainPath[0]);
    compilation->addDescription(Profiler::CompiledBytecode(Profiler::OriginStack(), out.toCString()));
    
    reportInstructions(compilation, linkBuffer, "    ", m_labelForBytecodeIndexInMainPath, firstSlowLabel());
    compilation->addDescription(Profiler::CompiledBytecode(Profiler::OriginStack(), "    (End Of Main Path)\n"));
    reportInstructions(compilation, linkBuffer, "    (S) ", m_labelForBytecodeIndexInSlowPath, m_endOfSlowPath);
    compilation->addDescription(Profiler::CompiledBytecode(Profiler::OriginStack(), "    (End Of Slow Path)\n"));
    out.reset();
    dumpDisassembly(out, linkBuffer, m_endOfSlowPath, m_endOfCode);
    compilation->addDescription(Profiler::CompiledBytecode(Profiler::OriginStack(), out.toCString()));
}

void Disassembler::append(Vector<Disassembler::DumpedOp>& result, StringPrintStream& out, CodeOrigin& previousOrigin)
{
    result.append(DumpedOp(previousOrigin, out.toCString()));
    previousOrigin = CodeOrigin();
    out.reset();
}

void link(State& state)
{
    Graph& graph = state.graph;
    CodeBlock* codeBlock = graph.m_codeBlock;
    VM& vm = graph.m_vm;

    // LLVM will create its own jump tables as needed.
    codeBlock->clearSwitchJumpTables();

#if !FTL_USES_B3
    // What LLVM's stackmaps call stackSizeForLocals and what we call frameRegisterCount have a simple
    // relationship, though it's not obvious from reading the code. The easiest way to understand them
    // is to look at stackOffset, i.e. what you have to add to FP to get SP. For LLVM that is just:
    //
    //     stackOffset == -state.jitCode->stackmaps.stackSizeForLocals()
    //
    // The way we define frameRegisterCount is that it satisfies this equality:
    //
    //     stackOffset == virtualRegisterForLocal(frameRegisterCount - 1).offset() * sizeof(Register)
    //
    // We can simplify this when we apply virtualRegisterForLocal():
    //
    //     stackOffset == (-1 - (frameRegisterCount - 1)) * sizeof(Register)
    //     stackOffset == (-1 - frameRegisterCount + 1) * sizeof(Register)
    //     stackOffset == -frameRegisterCount * sizeof(Register)
    //
    // Therefore we just have:
    //
    //     frameRegisterCount == -stackOffset / sizeof(Register)
    //
    // If we substitute what we have above, we get:
    //
    //     frameRegisterCount == -(-state.jitCode->stackmaps.stackSizeForLocals()) / sizeof(Register)
    //     frameRegisterCount == state.jitCode->stackmaps.stackSizeForLocals() / sizeof(Register)
    state.jitCode->common.frameRegisterCount = state.jitCode->stackmaps.stackSizeForLocals() / sizeof(void*);
#endif

    state.jitCode->common.requiredRegisterCountForExit = graph.requiredRegisterCountForExit();

    if (!graph.m_plan.inlineCallFrames->isEmpty())
        state.jitCode->common.inlineCallFrames = graph.m_plan.inlineCallFrames;

    graph.registerFrozenValues();

    // Create the entrypoint. Note that we use this entrypoint totally differently
    // depending on whether we're doing OSR entry or not.
    CCallHelpers jit(&vm, codeBlock);

    std::unique_ptr<LinkBuffer> linkBuffer;

    CCallHelpers::Address frame = CCallHelpers::Address(
                                      CCallHelpers::stackPointerRegister, -static_cast<int32_t>(AssemblyHelpers::prologueStackPointerDelta()));

    if (Profiler::Compilation* compilation = graph.compilation()) {
        compilation->addDescription(
            Profiler::OriginStack(),
            toCString("Generated FTL JIT code for ", CodeBlockWithJITType(codeBlock, JITCode::FTLJIT), ", instruction count = ", graph.m_codeBlock->instructionCount(), ":\n"));

        graph.ensureDominators();
        graph.ensureNaturalLoops();

        const char* prefix = "    ";

        DumpContext dumpContext;
        StringPrintStream out;
        Node* lastNode = 0;
        for (size_t blockIndex = 0; blockIndex < graph.numBlocks(); ++blockIndex) {
            BasicBlock* block = graph.block(blockIndex);
            if (!block)
                continue;

            graph.dumpBlockHeader(out, prefix, block, Graph::DumpLivePhisOnly, &dumpContext);
            compilation->addDescription(Profiler::OriginStack(), out.toCString());
            out.reset();

            for (size_t nodeIndex = 0; nodeIndex < block->size(); ++nodeIndex) {
                Node* node = block->at(nodeIndex);

                Profiler::OriginStack stack;

                if (node->origin.semantic.isSet()) {
                    stack = Profiler::OriginStack(
                                *vm.m_perBytecodeProfiler, codeBlock, node->origin.semantic);
                }

                if (graph.dumpCodeOrigin(out, prefix, lastNode, node, &dumpContext)) {
                    compilation->addDescription(stack, out.toCString());
                    out.reset();
                }

                graph.dump(out, prefix, node, &dumpContext);
                compilation->addDescription(stack, out.toCString());
                out.reset();

                if (node->origin.semantic.isSet())
                    lastNode = node;
            }
        }

        dumpContext.dump(out, prefix);
//.........这里部分代码省略.........

void logRegisterPressure(Code& code)
{
    const unsigned totalColumns = 200;
    const unsigned registerColumns = 100;
    
    RegLiveness liveness(code);

    for (BasicBlock* block : code) {
        RegLiveness::LocalCalc localCalc(liveness, block);

        block->dumpHeader(WTF::dataFile());

        Vector<CString> instDumps;
        for (unsigned instIndex = block->size(); instIndex--;) {
            Inst& inst = block->at(instIndex);
            Inst* prevInst = block->get(instIndex - 1);

            localCalc.execute(instIndex);

            RegisterSet set;
            set.setAll(localCalc.live());
            Inst::forEachDefWithExtraClobberedRegs<Reg>(
                prevInst, &inst,
                [&] (Reg reg, Arg::Role, Arg::Type, Arg::Width) {
                    set.set(reg);
                });

            StringPrintStream instOut;
            StringPrintStream lineOut;
            lineOut.print("   ");
            if (set.numberOfSetRegisters()) {
                set.forEach(
                    [&] (Reg reg) {
                        CString text = toCString(" ", reg);
                        if (text.length() + lineOut.length() > totalColumns) {
                            instOut.print(lineOut.toCString(), "\n");
                            lineOut.reset();
                            lineOut.print("       ");
                        }
                        lineOut.print(text);
                    });
                lineOut.print(":");
            }
            if (lineOut.length() > registerColumns) {
                instOut.print(lineOut.toCString(), "\n");
                lineOut.reset();
            }
            while (lineOut.length() < registerColumns)
                lineOut.print(" ");
            lineOut.print(" ");
            lineOut.print(inst);
            instOut.print(lineOut.toCString(), "\n");
            instDumps.append(instOut.toCString());
        }

        for (unsigned i = instDumps.size(); i--;)
            dataLog(instDumps[i]);
        
        block->dumpFooter(WTF::dataFile());
    }
}