// Copyright 2014 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 <cmath>
#include <functional>
#include <limits>
#include <memory>

#include "src/assembler.h"
#include "src/base/bits.h"
#include "src/codegen.h"
#include "src/compiler.h"
#include "src/compiler/linkage.h"
#include "src/machine-type.h"
#include "src/macro-assembler.h"
#include "src/objects-inl.h"
#include "test/cctest/cctest.h"
#include "test/cctest/compiler/codegen-tester.h"
#include "test/cctest/compiler/value-helper.h"

namespace v8 {
namespace internal {
namespace compiler {

namespace {

int size(MachineType type) {
  return 1 << ElementSizeLog2Of(type.representation());
}

int num_registers(MachineType type) {
  const RegisterConfiguration* config = RegisterConfiguration::Default();
  switch (type.representation()) {
    case MachineRepresentation::kWord32:
    case MachineRepresentation::kWord64:
      return config->num_allocatable_general_registers();
    case MachineRepresentation::kFloat32:
      return config->num_allocatable_float_registers();
    case MachineRepresentation::kFloat64:
      return config->num_allocatable_double_registers();
    default:
      UNREACHABLE();
  }
}

const int* codes(MachineType type) {
  const RegisterConfiguration* config = RegisterConfiguration::Default();
  switch (type.representation()) {
    case MachineRepresentation::kWord32:
    case MachineRepresentation::kWord64:
      return config->allocatable_general_codes();
    case MachineRepresentation::kFloat32:
      return config->allocatable_float_codes();
    case MachineRepresentation::kFloat64:
      return config->allocatable_double_codes();
    default:
      UNREACHABLE();
  }
}

CallDescriptor* CreateMonoCallDescriptor(Zone* zone, int return_count,
                                         int param_count, MachineType type) {
  LocationSignature::Builder locations(zone, return_count, param_count);

  int span = std::max(1, size(type) / kPointerSize);
  int stack_params = 0;
  for (int i = 0; i < param_count; i++) {
    LinkageLocation location = LinkageLocation::ForAnyRegister();
    if (i < num_registers(type)) {
      location = LinkageLocation::ForRegister(codes(type)[i], type);
    } else {
      int slot = span * (i - param_count);
      location = LinkageLocation::ForCallerFrameSlot(slot, type);
      stack_params += span;
    }
    locations.AddParam(location);
  }

  int stack_returns = 0;
  for (int i = 0; i < return_count; i++) {
    LinkageLocation location = LinkageLocation::ForAnyRegister();
    if (i < num_registers(type)) {
      location = LinkageLocation::ForRegister(codes(type)[i], type);
    } else {
      int slot = span * (num_registers(type) - i) - stack_params - 1;
      location = LinkageLocation::ForCallerFrameSlot(slot, type);
      stack_returns += span;
    }
    locations.AddReturn(location);
  }

  const RegList kCalleeSaveRegisters = 0;
  const RegList kCalleeSaveFPRegisters = 0;

  MachineType target_type = MachineType::AnyTagged();
  LinkageLocation target_loc = LinkageLocation::ForAnyRegister(target_type);
  return new (zone) CallDescriptor(       // --
      CallDescriptor::kCallCodeObject,    // kind
      target_type,                        // target MachineType
      target_loc,                         // target location
      locations.Build(),                  // location_sig
      stack_params,                       // on-stack parameter count
      compiler::Operator::kNoProperties,  // properties
      kCalleeSaveRegisters,               // callee-saved registers
      kCalleeSaveFPRegisters,             // callee-saved fp regs
      CallDescriptor::kNoFlags,           // flags
      "c-call",                           // debug name
      0,                                  // allocatable registers
      stack_returns);                     // on-stack return count
}

}  // namespace

Node* Constant(RawMachineAssembler& m, MachineType type, int value) {
  switch (type.representation()) {
    case MachineRepresentation::kWord32:
      return m.Int32Constant(static_cast<int32_t>(value));
    case MachineRepresentation::kWord64:
      return m.Int64Constant(static_cast<int64_t>(value));
    case MachineRepresentation::kFloat32:
      return m.Float32Constant(static_cast<float>(value));
    case MachineRepresentation::kFloat64:
      return m.Float64Constant(static_cast<double>(value));
    default:
      UNREACHABLE();
  }
}

Node* Add(RawMachineAssembler& m, MachineType type, Node* a, Node* b) {
  switch (type.representation()) {
    case MachineRepresentation::kWord32:
      return m.Int32Add(a, b);
    case MachineRepresentation::kWord64:
      return m.Int64Add(a, b);
    case MachineRepresentation::kFloat32:
      return m.Float32Add(a, b);
    case MachineRepresentation::kFloat64:
      return m.Float64Add(a, b);
    default:
      UNREACHABLE();
  }
}

Node* Sub(RawMachineAssembler& m, MachineType type, Node* a, Node* b) {
  switch (type.representation()) {
    case MachineRepresentation::kWord32:
      return m.Int32Sub(a, b);
    case MachineRepresentation::kWord64:
      return m.Int64Sub(a, b);
    case MachineRepresentation::kFloat32:
      return m.Float32Sub(a, b);
    case MachineRepresentation::kFloat64:
      return m.Float64Sub(a, b);
    default:
      UNREACHABLE();
  }
}

Node* Mul(RawMachineAssembler& m, MachineType type, Node* a, Node* b) {
  switch (type.representation()) {
    case MachineRepresentation::kWord32:
      return m.Int32Mul(a, b);
    case MachineRepresentation::kWord64:
      return m.Int64Mul(a, b);
    case MachineRepresentation::kFloat32:
      return m.Float32Mul(a, b);
    case MachineRepresentation::kFloat64:
      return m.Float64Mul(a, b);
    default:
      UNREACHABLE();
  }
}

Node* ToInt32(RawMachineAssembler& m, MachineType type, Node* a) {
  switch (type.representation()) {
    case MachineRepresentation::kWord32:
      return a;
    case MachineRepresentation::kWord64:
      return m.TruncateInt64ToInt32(a);
    case MachineRepresentation::kFloat32:
      return m.TruncateFloat32ToInt32(a);
    case MachineRepresentation::kFloat64:
      return m.RoundFloat64ToInt32(a);
    default:
      UNREACHABLE();
  }
}

void TestReturnMultipleValues(MachineType type) {
  const int kMaxCount = 20;
  for (int count = 0; count < kMaxCount; ++count) {
    printf("\n==== type = %s, count = %d ====\n\n\n",
           MachineReprToString(type.representation()), count);
    v8::internal::AccountingAllocator allocator;
    Zone zone(&allocator, ZONE_NAME);
    CallDescriptor* desc = CreateMonoCallDescriptor(&zone, count, 2, type);
    HandleAndZoneScope handles;
    RawMachineAssembler m(handles.main_isolate(),
                          new (handles.main_zone()) Graph(handles.main_zone()),
                          desc, MachineType::PointerRepresentation(),
                          InstructionSelector::SupportedMachineOperatorFlags());

    Node* p0 = m.Parameter(0);
    Node* p1 = m.Parameter(1);
    typedef Node* Node_ptr;
    std::unique_ptr<Node_ptr[]> returns(new Node_ptr[count]);
    for (int i = 0; i < count; ++i) {
      if (i % 3 == 0) returns[i] = Add(m, type, p0, p1);
      if (i % 3 == 1) returns[i] = Sub(m, type, p0, p1);
      if (i % 3 == 2) returns[i] = Mul(m, type, p0, p1);
    }
    m.Return(count, returns.get());

    CompilationInfo info(ArrayVector("testing"), handles.main_zone(),
                         Code::STUB);
    Handle<Code> code = Pipeline::GenerateCodeForTesting(
        &info, handles.main_isolate(), desc, m.graph(), m.Export());
#ifdef ENABLE_DISASSEMBLER
    if (FLAG_print_code) {
      OFStream os(stdout);
      code->Disassemble("multi_value", os);
    }
#endif

    const int a = 47, b = 12;
    int expect = 0;
    for (int i = 0, sign = +1; i < count; ++i) {
      if (i % 3 == 0) expect += sign * (a + b);
      if (i % 3 == 1) expect += sign * (a - b);
      if (i % 3 == 2) expect += sign * (a * b);
      if (i % 4 == 0) sign = -sign;
    }

    RawMachineAssemblerTester<int32_t> mt;
    Node* na = Constant(mt, type, a);
    Node* nb = Constant(mt, type, b);
    Node* ret_multi =
        mt.AddNode(mt.common()->Call(desc), mt.HeapConstant(code), na, nb);
    Node* ret = Constant(mt, type, 0);
    bool sign = false;
    for (int i = 0; i < count; ++i) {
      Node* x = (count == 1)
                    ? ret_multi
                    : mt.AddNode(mt.common()->Projection(i), ret_multi);
      ret = sign ? Sub(mt, type, ret, x) : Add(mt, type, ret, x);
      if (i % 4 == 0) sign = !sign;
    }
    mt.Return(ToInt32(mt, type, ret));
#ifdef ENABLE_DISASSEMBLER
    Handle<Code> code2 = mt.GetCode();
    if (FLAG_print_code) {
      OFStream os(stdout);
      code2->Disassemble("multi_value_call", os);
    }
#endif
    CHECK_EQ(expect, mt.Call());
  }
}

#define TEST_MULTI(Type, type) \
  TEST(ReturnMultiple##Type) { TestReturnMultipleValues(type); }

TEST_MULTI(Int32, MachineType::Int32())
#if (!V8_TARGET_ARCH_32_BIT)
TEST_MULTI(Int64, MachineType::Int64())
#endif
TEST_MULTI(Float32, MachineType::Float32())
TEST_MULTI(Float64, MachineType::Float64())

#undef TEST_MULTI

void ReturnLastValue(MachineType type) {
  int slot_counts[] = {1, 2, 3, 600};
  for (auto slot_count : slot_counts) {
    v8::internal::AccountingAllocator allocator;
    Zone zone(&allocator, ZONE_NAME);
    const int return_count = num_registers(type) + slot_count;

    CallDescriptor* desc =
        CreateMonoCallDescriptor(&zone, return_count, 0, type);

    HandleAndZoneScope handles;
    RawMachineAssembler m(handles.main_isolate(),
                          new (handles.main_zone()) Graph(handles.main_zone()),
                          desc, MachineType::PointerRepresentation(),
                          InstructionSelector::SupportedMachineOperatorFlags());

    std::unique_ptr<Node* []> returns(new Node*[return_count]);

    for (int i = 0; i < return_count; ++i) {
      returns[i] = Constant(m, type, i);
    }

    m.Return(return_count, returns.get());

    CompilationInfo info(ArrayVector("testing"), handles.main_zone(),
                         Code::STUB);
    Handle<Code> code = Pipeline::GenerateCodeForTesting(
        &info, handles.main_isolate(), desc, m.graph(), m.Export());

    // Generate caller.
    int expect = return_count - 1;
    RawMachineAssemblerTester<int32_t> mt;
    Node* code_node = mt.HeapConstant(code);

    Node* call = mt.AddNode(mt.common()->Call(desc), 1, &code_node);

    mt.Return(ToInt32(
        mt, type, mt.AddNode(mt.common()->Projection(return_count - 1), call)));

    CHECK_EQ(expect, mt.Call());
  }
}

TEST(ReturnLastValueInt32) { ReturnLastValue(MachineType::Int32()); }
#if (!V8_TARGET_ARCH_32_BIT)
TEST(ReturnLastValueInt64) { ReturnLastValue(MachineType::Int64()); }
#endif
TEST(ReturnLastValueFloat32) { ReturnLastValue(MachineType::Float32()); }
TEST(ReturnLastValueFloat64) { ReturnLastValue(MachineType::Float64()); }

void ReturnSumOfReturns(MachineType type) {
  for (int unused_stack_slots = 0; unused_stack_slots <= 2;
       ++unused_stack_slots) {
    v8::internal::AccountingAllocator allocator;
    Zone zone(&allocator, ZONE_NAME);
    // Let {unused_stack_slots + 1} returns be on the stack.
    const int return_count = num_registers(type) + unused_stack_slots + 1;

    CallDescriptor* desc =
        CreateMonoCallDescriptor(&zone, return_count, 0, type);

    HandleAndZoneScope handles;
    RawMachineAssembler m(handles.main_isolate(),
                          new (handles.main_zone()) Graph(handles.main_zone()),
                          desc, MachineType::PointerRepresentation(),
                          InstructionSelector::SupportedMachineOperatorFlags());

    std::unique_ptr<Node* []> returns(new Node*[return_count]);

    for (int i = 0; i < return_count; ++i) {
      returns[i] = Constant(m, type, i);
    }

    m.Return(return_count, returns.get());

    CompilationInfo info(ArrayVector("testing"), handles.main_zone(),
                         Code::STUB);
    Handle<Code> code = Pipeline::GenerateCodeForTesting(
        &info, handles.main_isolate(), desc, m.graph(), m.Export());

    // Generate caller.
    RawMachineAssemblerTester<int32_t> mt;
    Node* code_node = mt.HeapConstant(code);

    Node* call = mt.AddNode(mt.common()->Call(desc), 1, &code_node);

    uint32_t expect = 0;
    Node* result = mt.Int32Constant(0);

    for (int i = 0; i < return_count; ++i) {
      expect += i;
      result = mt.Int32Add(
          result,
          ToInt32(mt, type, mt.AddNode(mt.common()->Projection(i), call)));
    }

    mt.Return(result);

    CHECK_EQ(expect, mt.Call());
  }
}

TEST(ReturnSumOfReturnsInt32) { ReturnSumOfReturns(MachineType::Int32()); }
#if (!V8_TARGET_ARCH_32_BIT)
TEST(ReturnSumOfReturnsInt64) { ReturnSumOfReturns(MachineType::Int64()); }
#endif
TEST(ReturnSumOfReturnsFloat32) { ReturnSumOfReturns(MachineType::Float32()); }
TEST(ReturnSumOfReturnsFloat64) { ReturnSumOfReturns(MachineType::Float64()); }

}  // namespace compiler
}  // namespace internal
}  // namespace v8