src/code-stubs.cc

// Copyright 2006-2008 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
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#include "v8.h"

#include "bootstrapper.h"
#include "code-stubs.h"
#include "factory.h"
#include "macro-assembler.h"
#include "oprofile-agent.h"

namespace v8 {
namespace internal {

bool CodeStub::FindCodeInCache(Code** code_out) {
  int index = Heap::code_stubs()->FindEntry(GetKey());
  if (index != NumberDictionary::kNotFound) {
    *code_out = Code::cast(Heap::code_stubs()->ValueAt(index));
    return true;
  }
  return false;
}


void CodeStub::GenerateCode(MacroAssembler* masm) {
  // Update the static counter each time a new code stub is generated.
  Counters::code_stubs.Increment();
  // Nested stubs are not allowed for leafs.
  masm->set_allow_stub_calls(AllowsStubCalls());
  // Generate the code for the stub.
  masm->set_generating_stub(true);
  Generate(masm);
}


void CodeStub::RecordCodeGeneration(Code* code, MacroAssembler* masm) {
  code->set_major_key(MajorKey());

  OPROFILE(CreateNativeCodeRegion(GetName(),
                                  code->instruction_start(),
                                  code->instruction_size()));
  PROFILE(CodeCreateEvent(Logger::STUB_TAG, code, GetName()));
  Counters::total_stubs_code_size.Increment(code->instruction_size());

#ifdef ENABLE_DISASSEMBLER
  if (FLAG_print_code_stubs) {
#ifdef DEBUG
    Print();
#endif
    code->Disassemble(GetName());
    PrintF("\n");
  }
#endif
}


int CodeStub::GetCodeKind() {
  return Code::STUB;
}


Handle<Code> CodeStub::GetCode() {
  Code* code;
  if (!FindCodeInCache(&code)) {
    v8::HandleScope scope;

    // Generate the new code.
    MacroAssembler masm(NULL, 256);
    GenerateCode(&masm);

    // Create the code object.
    CodeDesc desc;
    masm.GetCode(&desc);

    // Copy the generated code into a heap object.
    Code::Flags flags = Code::ComputeFlags(
        static_cast<Code::Kind>(GetCodeKind()),
        InLoop(),
        GetICState());
    Handle<Code> new_object = Factory::NewCode(desc, flags, masm.CodeObject());
    RecordCodeGeneration(*new_object, &masm);

    // Update the dictionary and the root in Heap.
    Handle<NumberDictionary> dict =
        Factory::DictionaryAtNumberPut(
            Handle<NumberDictionary>(Heap::code_stubs()),
            GetKey(),
            new_object);
    Heap::public_set_code_stubs(*dict);

    code = *new_object;
  }

  return Handle<Code>(code);
}


MaybeObject* CodeStub::TryGetCode() {
  Code* code;
  if (!FindCodeInCache(&code)) {
    // Generate the new code.
    MacroAssembler masm(NULL, 256);
    GenerateCode(&masm);

    // Create the code object.
    CodeDesc desc;
    masm.GetCode(&desc);

    // Try to copy the generated code into a heap object.
    Code::Flags flags = Code::ComputeFlags(
        static_cast<Code::Kind>(GetCodeKind()),
        InLoop(),
        GetICState());
    Object* new_object;
    { MaybeObject* maybe_new_object =
          Heap::CreateCode(desc, flags, masm.CodeObject());
      if (!maybe_new_object->ToObject(&new_object)) return maybe_new_object;
    }
    code = Code::cast(new_object);
    RecordCodeGeneration(code, &masm);

    // Try to update the code cache but do not fail if unable.
    MaybeObject* maybe_new_object =
        Heap::code_stubs()->AtNumberPut(GetKey(), code);
    if (maybe_new_object->ToObject(&new_object)) {
      Heap::public_set_code_stubs(NumberDictionary::cast(new_object));
    }
  }

  return code;
}


const char* CodeStub::MajorName(CodeStub::Major major_key,
                                bool allow_unknown_keys) {
  switch (major_key) {
#define DEF_CASE(name) case name: return #name;
    CODE_STUB_LIST(DEF_CASE)
#undef DEF_CASE
    default:
      if (!allow_unknown_keys) {
        UNREACHABLE();
      }
      return NULL;
  }
}


} }  // namespace v8::internal