text: // Copyright 2012 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "src/codegen.h"
  
  #if defined(V8_OS_AIX)
  #include <fenv.h>  // NOLINT(build/c++11)
  #endif
  
  #include <memory>
  
  #include "src/ast/prettyprinter.h"
  #include "src/bootstrapper.h"
  #include "src/compilation-info.h"
  #include "src/counters.h"
  #include "src/debug/debug.h"
  #include "src/eh-frame.h"
  #include "src/objects-inl.h"
  #include "src/runtime/runtime.h"
  
  namespace v8 {
  namespace internal {
  
  
  #if defined(V8_OS_WIN)
  double modulo(double x, double y) {
    // Workaround MS fmod bugs. ECMA-262 says:
    // dividend is finite and divisor is an infinity => result equals dividend
    // dividend is a zero and divisor is nonzero finite => result equals dividend
    if (!(std::isfinite(x) && (!std::isfinite(y) && !std::isnan(y))) &&
        !(x == 0 && (y != 0 && std::isfinite(y)))) {
      x = fmod(x, y);
    }
    return x;
  }
  #else  // POSIX
  
  double modulo(double x, double y) {
  #if defined(V8_OS_AIX)
    // AIX raises an underflow exception for (Number.MIN_VALUE % Number.MAX_VALUE)
    feclearexcept(FE_ALL_EXCEPT);
    double result = std::fmod(x, y);
    int exception = fetestexcept(FE_UNDERFLOW);
    return (exception ? x : result);
  #else
    return std::fmod(x, y);
  #endif
  }
  #endif  // defined(V8_OS_WIN)
  
  
  #define UNARY_MATH_FUNCTION(name, generator)                             \
    static UnaryMathFunctionWithIsolate fast_##name##_function = nullptr;  \
    double std_##name(double x, Isolate* isolate) { return std::name(x); } \
    void init_fast_##name##_function(Isolate* isolate) {                   \
      if (FLAG_fast_math) fast_##name##_function = generator(isolate);     \
      if (!fast_##name##_function) fast_##name##_function = std_##name;    \
    }                                                                      \
    void lazily_initialize_fast_##name(Isolate* isolate) {                 \
      if (!fast_##name##_function) init_fast_##name##_function(isolate);   \
    }                                                                      \
    double fast_##name(double x, Isolate* isolate) {                       \
      return (*fast_##name##_function)(x, isolate);                        \
    }
  
  UNARY_MATH_FUNCTION(sqrt, CreateSqrtFunction)
  
  #undef UNARY_MATH_FUNCTION
  
  
  #ifdef DEBUG
  
  Comment::Comment(Assembler* assembler, const char* msg)
      : assembler_(assembler), msg_(msg) {
    assembler_->RecordComment(msg);
  }
  
  
  Comment::~Comment() {
    if (msg_[0] == '[') assembler_->RecordComment("]");
  }
  
  #endif  // DEBUG
  
  
  void CodeGenerator::MakeCodePrologue(CompilationInfo* info, const char* kind) {
    bool print_ast = false;
    const char* ftype;
  
    if (info->isolate()->bootstrapper()->IsActive()) {
      print_ast = FLAG_print_builtin_ast;
      ftype = "builtin";
    } else {
      print_ast = FLAG_print_ast;
      ftype = "user-defined";
    }
  
    if (FLAG_trace_codegen || print_ast) {
      std::unique_ptr<char[]> name = info->GetDebugName();
      PrintF("[generating %s code for %s function: %s]\n", kind, ftype,
             name.get());
    }
  
  #ifdef DEBUG
    if (info->parse_info() && print_ast) {
      PrintF("--- AST ---\n%s\n",
             AstPrinter(info->isolate()).PrintProgram(info->literal()));
    }
  #endif  // DEBUG
  }
  
  Handle<Code> CodeGenerator::MakeCodeEpilogue(MacroAssembler* masm,
                                               EhFrameWriter* eh_frame_writer,
                                               CompilationInfo* info,
                                               Handle<Object> self_reference) {
    Isolate* isolate = info->isolate();
  
    // Allocate and install the code.
    CodeDesc desc;
    Code::Flags flags = info->code_flags();
    bool is_crankshafted =
        Code::ExtractKindFromFlags(flags) == Code::OPTIMIZED_FUNCTION ||
        info->IsStub();
    masm->GetCode(&desc);
    if (eh_frame_writer) eh_frame_writer->GetEhFrame(&desc);
  
    Handle<Code> code = isolate->factory()->NewCode(
        desc, flags, self_reference, false, is_crankshafted,
        info->prologue_offset(), info->is_debug() && !is_crankshafted);
    isolate->counters()->total_compiled_code_size()->Increment(
        code->instruction_size());
    return code;
  }
  
  // Print function's source if it was not printed before.
  // Return a sequential id under which this function was printed.
  static int PrintFunctionSource(CompilationInfo* info,
                                 std::vector<Handle<SharedFunctionInfo>>* printed,
                                 int inlining_id,
                                 Handle<SharedFunctionInfo> shared) {
    // Outermost function has source id -1 and inlined functions take
    // source ids starting from 0.
    int source_id = -1;
    if (inlining_id != SourcePosition::kNotInlined) {
      for (unsigned i = 0; i < printed->size(); i++) {
        if (printed->at(i).is_identical_to(shared)) {
          return i;
        }
      }
      source_id = static_cast<int>(printed->size());
      printed->push_back(shared);
    }
  
    Isolate* isolate = info->isolate();
    if (!shared->script()->IsUndefined(isolate)) {
      Handle<Script> script(Script::cast(shared->script()), isolate);
  
      if (!script->source()->IsUndefined(isolate)) {
        CodeTracer::Scope tracing_scope(isolate->GetCodeTracer());
        Object* source_name = script->name();
        OFStream os(tracing_scope.file());
        os << "--- FUNCTION SOURCE (";
        if (source_name->IsString()) {
          os << String::cast(source_name)->ToCString().get() << ":";
        }
        os << shared->DebugName()->ToCString().get() << ") id{";
        os << info->optimization_id() << "," << source_id << "} start{";
        os << shared->start_position() << "} ---\n";
        {
          DisallowHeapAllocation no_allocation;
          int start = shared->start_position();
          int len = shared->end_position() - start;
          String::SubStringRange source(String::cast(script->source()), start,
                                        len);
          for (const auto& c : source) {
            os << AsReversiblyEscapedUC16(c);
          }
        }
  
        os << "\n--- END ---\n";
      }
    }
  
    return source_id;
  }
  
  // Print information for the given inlining: which function was inlined and
  // where the inlining occured.
  static void PrintInlinedFunctionInfo(
      CompilationInfo* info, int source_id, int inlining_id,
      const CompilationInfo::InlinedFunctionHolder& h) {
    CodeTracer::Scope tracing_scope(info->isolate()->GetCodeTracer());
    OFStream os(tracing_scope.file());
    os << "INLINE (" << h.shared_info->DebugName()->ToCString().get() << ") id{"
       << info->optimization_id() << "," << source_id << "} AS " << inlining_id
       << " AT ";
    const SourcePosition position = h.position.position;
    if (position.IsKnown()) {
      os << "<" << position.InliningId() << ":" << position.ScriptOffset() << ">";
    } else {
      os << "<?>";
    }
    os << std::endl;
  }
  
  // Print the source of all functions that participated in this optimizing
  // compilation. For inlined functions print source position of their inlining.
  static void DumpParticipatingSource(CompilationInfo* info) {
    AllowDeferredHandleDereference allow_deference_for_print_code;
  
    std::vector<Handle<SharedFunctionInfo>> printed;
    printed.reserve(info->inlined_functions().size());
  
    PrintFunctionSource(info, &printed, SourcePosition::kNotInlined,
                        info->shared_info());
    const auto& inlined = info->inlined_functions();
    for (unsigned id = 0; id < inlined.size(); id++) {
      const int source_id =
          PrintFunctionSource(info, &printed, id, inlined[id].shared_info);
      PrintInlinedFunctionInfo(info, source_id, id, inlined[id]);
    }
  }
  
  void CodeGenerator::PrintCode(Handle<Code> code, CompilationInfo* info) {
    if (FLAG_print_opt_source && info->IsOptimizing()) {
      DumpParticipatingSource(info);
    }
  
  #ifdef ENABLE_DISASSEMBLER
    AllowDeferredHandleDereference allow_deference_for_print_code;
    Isolate* isolate = info->isolate();
    bool print_code =
        isolate->bootstrapper()->IsActive()
            ? FLAG_print_builtin_code
            : (FLAG_print_code || (info->IsStub() && FLAG_print_code_stubs) ||
               (info->IsOptimizing() && FLAG_print_opt_code &&
                info->shared_info()->PassesFilter(FLAG_print_opt_code_filter)) ||
               (info->IsWasm() && FLAG_print_wasm_code));
    if (print_code) {
      std::unique_ptr<char[]> debug_name = info->GetDebugName();
      CodeTracer::Scope tracing_scope(info->isolate()->GetCodeTracer());
      OFStream os(tracing_scope.file());
  
      // Print the source code if available.
      bool print_source =
          info->parse_info() && (code->kind() == Code::OPTIMIZED_FUNCTION ||
                                 code->kind() == Code::FUNCTION);
      if (print_source) {
        Handle<SharedFunctionInfo> shared = info->shared_info();
        Handle<Script> script = info->script();
        if (!script->IsUndefined(isolate) &&
            !script->source()->IsUndefined(isolate)) {
          os << "--- Raw source ---\n";
          StringCharacterStream stream(String::cast(script->source()),
                                       shared->start_position());
          // fun->end_position() points to the last character in the stream. We
          // need to compensate by adding one to calculate the length.
          int source_len = shared->end_position() - shared->start_position() + 1;
          for (int i = 0; i < source_len; i++) {
            if (stream.HasMore()) {
              os << AsReversiblyEscapedUC16(stream.GetNext());
            }
          }
          os << "\n\n";
        }
      }
      if (info->IsOptimizing()) {
        if (FLAG_print_unopt_code && info->parse_info()) {
          os << "--- Unoptimized code ---\n";
          info->closure()->shared()->code()->Disassemble(debug_name.get(), os);
        }
        os << "--- Optimized code ---\n"
           << "optimization_id = " << info->optimization_id() << "\n";
      } else {
        os << "--- Code ---\n";
      }
      if (print_source) {
        Handle<SharedFunctionInfo> shared = info->shared_info();
        os << "source_position = " << shared->start_position() << "\n";
      }
      code->Disassemble(debug_name.get(), os);
      os << "--- End code ---\n";
    }
  #endif  // ENABLE_DISASSEMBLER
  }
  
  }  // namespace internal
  }  // namespace v8
  