// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
// Class for intrinsifying functions.

#include "vm/compiler/intrinsifier.h"

#include "vm/compiler/assembler/assembler.h"
#include "vm/compiler/backend/flow_graph.h"
#include "vm/compiler/backend/flow_graph_compiler.h"
#include "vm/compiler/backend/il_printer.h"
#include "vm/compiler/backend/linearscan.h"
#include "vm/compiler/frontend/flow_graph_builder.h"
#include "vm/compiler/jit/compiler.h"
#include "vm/cpu.h"
#include "vm/flags.h"
#include "vm/object.h"
#include "vm/parser.h"
#include "vm/symbols.h"

namespace dart {

DEFINE_FLAG(bool, intrinsify, true, "Instrinsify when possible");
DEFINE_FLAG(bool, trace_intrinsifier, false, "Trace intrinsifier");

namespace compiler {

bool Intrinsifier::CanIntrinsify(const Function& function) {
  if (FLAG_trace_intrinsifier) {
    THR_Print("CanIntrinsify %s ->", function.ToQualifiedCString());
  }
  if (!FLAG_intrinsify) return false;
  // TODO(regis): We do not need to explicitly filter generic functions here,
  // unless there are errors we don't detect at link time. Revisit if necessary.
  if (function.IsClosureFunction()) {
    if (FLAG_trace_intrinsifier) {
      THR_Print("No, closure function.\n");
    }
    return false;
  }
  // Can occur because of compile-all flag.
  if (function.is_external()) {
    if (FLAG_trace_intrinsifier) {
      THR_Print("No, external function.\n");
    }
    return false;
  }
  if (!function.is_intrinsic()) {
    if (FLAG_trace_intrinsifier) {
      THR_Print("No, not intrinsic function.\n");
    }
    return false;
  }
  switch (function.recognized_kind()) {
    case MethodRecognizer::kInt64ArrayGetIndexed:
    case MethodRecognizer::kInt64ArraySetIndexed:
    case MethodRecognizer::kUint64ArrayGetIndexed:
    case MethodRecognizer::kUint64ArraySetIndexed:
      // TODO(ajcbik): consider 32-bit as well.
      if (target::kBitsPerWord == 64 &&
          FlowGraphCompiler::SupportsUnboxedInt64()) {
        break;
      }
      if (FLAG_trace_intrinsifier) {
        THR_Print("No, 64-bit int intrinsic on 32-bit platform.\n");
      }
      return false;
    default:
      break;
  }
  if (FLAG_trace_intrinsifier) {
    THR_Print("Yes.\n");
  }
  return true;
}

struct IntrinsicDesc {
  const char* class_name;
  const char* function_name;
};

struct LibraryInstrinsicsDesc {
  Library& library;
  IntrinsicDesc* intrinsics;
};

#define DEFINE_INTRINSIC(class_name, function_name, destination, fp)           \
  {#class_name, #function_name},

// clang-format off
static IntrinsicDesc core_intrinsics[] = {
  CORE_LIB_INTRINSIC_LIST(DEFINE_INTRINSIC)
  CORE_INTEGER_LIB_INTRINSIC_LIST(DEFINE_INTRINSIC)
  GRAPH_CORE_INTRINSICS_LIST(DEFINE_INTRINSIC)
  {nullptr, nullptr},
};

static IntrinsicDesc math_intrinsics[] = {
  MATH_LIB_INTRINSIC_LIST(DEFINE_INTRINSIC)
  GRAPH_MATH_LIB_INTRINSIC_LIST(DEFINE_INTRINSIC)
  {nullptr, nullptr},
};

static IntrinsicDesc typed_data_intrinsics[] = {
  TYPED_DATA_LIB_INTRINSIC_LIST(DEFINE_INTRINSIC)
  GRAPH_TYPED_DATA_INTRINSICS_LIST(DEFINE_INTRINSIC)
  {nullptr, nullptr},
};

static IntrinsicDesc developer_intrinsics[] = {
  DEVELOPER_LIB_INTRINSIC_LIST(DEFINE_INTRINSIC)
  {nullptr, nullptr},
};
// clang-format on

void Intrinsifier::InitializeState() {
  Thread* thread = Thread::Current();
  Zone* zone = thread->zone();
  Library& lib = Library::Handle(zone);
  Class& cls = Class::Handle(zone);
  Function& func = Function::Handle(zone);
  String& str = String::Handle(zone);
  String& str2 = String::Handle(zone);
  Error& error = Error::Handle(zone);

  static const intptr_t kNumLibs = 4;
  LibraryInstrinsicsDesc intrinsics[kNumLibs] = {
      {Library::Handle(zone, Library::CoreLibrary()), core_intrinsics},
      {Library::Handle(zone, Library::MathLibrary()), math_intrinsics},
      {Library::Handle(zone, Library::TypedDataLibrary()),
       typed_data_intrinsics},
      {Library::Handle(zone, Library::DeveloperLibrary()),
       developer_intrinsics},
  };

  for (intptr_t i = 0; i < kNumLibs; i++) {
    lib = intrinsics[i].library.raw();
    for (IntrinsicDesc* intrinsic = intrinsics[i].intrinsics;
         intrinsic->class_name != nullptr; intrinsic++) {
      func = Function::null();
      if (strcmp(intrinsic->class_name, "::") == 0) {
        str = String::New(intrinsic->function_name);
        func = lib.LookupFunctionAllowPrivate(str);
      } else {
        str = String::New(intrinsic->class_name);
        cls = lib.LookupClassAllowPrivate(str);
        ASSERT(FLAG_precompiled_mode || !cls.IsNull());
        if (!cls.IsNull()) {
          error = cls.EnsureIsFinalized(thread);
          if (!error.IsNull()) {
            OS::PrintErr("%s\n", error.ToErrorCString());
          }
          ASSERT(error.IsNull());
          str = String::New(intrinsic->function_name);
          if (intrinsic->function_name[0] == '.') {
            str2 = String::New(intrinsic->class_name);
            str = String::Concat(str2, str);
          }
          func = cls.LookupFunctionAllowPrivate(str);
        }
      }
      if (!func.IsNull()) {
        func.set_is_intrinsic(true);
      } else if (!FLAG_precompiled_mode) {
        FATAL2("Intrinsifier failed to find method %s in class %s\n",
               intrinsic->function_name, intrinsic->class_name);
      }
    }
  }
#undef SETUP_FUNCTION
}

// Returns true if fall-through code can be omitted.
bool Intrinsifier::Intrinsify(const ParsedFunction& parsed_function,
                              FlowGraphCompiler* compiler) {
  const Function& function = parsed_function.function();
  if (!CanIntrinsify(function)) {
    return false;
  }

  ASSERT(!compiler->flow_graph().IsCompiledForOsr());
  if (GraphIntrinsifier::GraphIntrinsify(parsed_function, compiler)) {
    return compiler->intrinsic_slow_path_label()->IsUnused();
  }

#if !defined(HASH_IN_OBJECT_HEADER)
  // These two are more complicated on 32 bit platforms, where the
  // identity hash is not stored in the header of the object.  We
  // therefore don't intrinsify them, falling back on the native C++
  // implementations.
  if (function.recognized_kind() == MethodRecognizer::kObject_getHash ||
      function.recognized_kind() == MethodRecognizer::kObject_setHash) {
    return false;
  }
#endif

#if !defined(PRODUCT)
#define EMIT_BREAKPOINT() compiler->assembler()->Breakpoint()
#else
#define EMIT_BREAKPOINT()
#endif

#define EMIT_CASE(class_name, function_name, enum_name, fp)                    \
  case MethodRecognizer::k##enum_name: {                                       \
    compiler->assembler()->Comment("Intrinsic");                               \
    Label normal_ir_body;                                                      \
    const auto size_before = compiler->assembler()->CodeSize();                \
    AsmIntrinsifier::enum_name(compiler->assembler(), &normal_ir_body);        \
    const auto size_after = compiler->assembler()->CodeSize();                 \
    if (size_before == size_after) return false;                               \
    if (!normal_ir_body.IsBound()) {                                           \
      EMIT_BREAKPOINT();                                                       \
      return true;                                                             \
    }                                                                          \
    return false;                                                              \
  }

  switch (function.recognized_kind()) {
    ALL_INTRINSICS_NO_INTEGER_LIB_LIST(EMIT_CASE);
    default:
      break;
  }
  switch (function.recognized_kind()) {
    CORE_INTEGER_LIB_INTRINSIC_LIST(EMIT_CASE)
    default:
      break;
  }

#undef EMIT_BREAKPOINT

#undef EMIT_INTRINSIC
  return false;
}

}  // namespace compiler
}  // namespace dart