// 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 "src/compiler/common-operator.h"
#include "src/compiler/graph.h"
#include "src/compiler/linkage.h"
#include "src/compiler/node.h"
#include "test/unittests/test-utils.h"

namespace v8 {
namespace internal {
namespace compiler {

namespace {

MachineType kMachineTypes[] = {
    MachineType::AnyTagged(), MachineType::AnyTagged(),
    MachineType::AnyTagged(), MachineType::AnyTagged(),
    MachineType::AnyTagged(), MachineType::AnyTagged(),
    MachineType::AnyTagged(), MachineType::AnyTagged()};
}

class LinkageTailCall : public TestWithZone {
 protected:
  LinkageTailCall() : TestWithZone(kCompressGraphZone) {}

  CallDescriptor* NewStandardCallDescriptor(LocationSignature* locations) {
    DCHECK(arraysize(kMachineTypes) >=
           locations->return_count() + locations->parameter_count());
    USE(kMachineTypes);
    size_t stack_arguments = 0;
    for (size_t i = 0; i < locations->parameter_count(); ++i) {
      if (locations->GetParam(i).IsCallerFrameSlot()) stack_arguments++;
    }
    size_t stack_returns = 0;
    for (size_t i = 0; i < locations->return_count(); ++i) {
      if (locations->GetReturn(i).IsCallerFrameSlot()) stack_returns++;
    }
    return zone()->New<CallDescriptor>(
        CallDescriptor::kCallCodeObject, MachineType::AnyTagged(),
        LinkageLocation::ForAnyRegister(MachineType::Pointer()),
        locations,  // location_sig
        stack_arguments,
        Operator::kNoProperties,   // properties
        0,                         // callee-saved
        0,                         // callee-saved fp
        CallDescriptor::kNoFlags,  // flags,
        "", StackArgumentOrder::kDefault,
#if V8_ENABLE_WEBASSEMBLY
        nullptr,  // wasm function sig
#endif
        0,  // allocatable_registers
        stack_returns);
  }

  LinkageLocation StackLocation(int loc) {
    return LinkageLocation::ForCallerFrameSlot(-loc, MachineType::Pointer());
  }

  LinkageLocation RegisterLocation(int loc) {
    return LinkageLocation::ForRegister(loc, MachineType::Pointer());
  }
};


TEST_F(LinkageTailCall, EmptyToEmpty) {
  LocationSignature locations(0, 0, nullptr);
  CallDescriptor* desc = NewStandardCallDescriptor(&locations);
  CommonOperatorBuilder common(zone());
  const Operator* op = common.Call(desc);
  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
  const CallDescriptor* callee = CallDescriptorOf(node->op());
  EXPECT_TRUE(desc->CanTailCall(callee));
  int stack_param_delta = callee->GetStackParameterDelta(desc);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, SameReturn) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0)};
  LocationSignature locations1(1, 0, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);

  CommonOperatorBuilder common(zone());
  const Operator* op = common.Call(desc2);
  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, DifferingReturn) {
  // Caller
  LinkageLocation location_array1[] = {RegisterLocation(0)};
  LocationSignature locations1(1, 0, location_array1);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LinkageLocation location_array2[] = {RegisterLocation(1)};
  LocationSignature locations2(1, 0, location_array2);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);

  CommonOperatorBuilder common(zone());
  const Operator* op = common.Call(desc2);
  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
  EXPECT_FALSE(desc1->CanTailCall(CallDescriptorOf(node->op())));
}


TEST_F(LinkageTailCall, MoreRegisterParametersCallee) {
  // Caller
  LinkageLocation location_array1[] = {RegisterLocation(0)};
  LocationSignature locations1(1, 0, location_array1);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LinkageLocation location_array2[] = {RegisterLocation(0),
                                       RegisterLocation(0)};
  LocationSignature locations2(1, 1, location_array2);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);

  CommonOperatorBuilder common(zone());
  const Operator* op = common.Call(desc2);
  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, MoreRegisterParametersCaller) {
  // Caller
  LinkageLocation location_array1[] = {RegisterLocation(0),
                                       RegisterLocation(0)};
  LocationSignature locations1(1, 1, location_array1);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LinkageLocation location_array2[] = {RegisterLocation(0)};
  LocationSignature locations2(1, 0, location_array2);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);

  CommonOperatorBuilder common(zone());
  const Operator* op = common.Call(desc2);
  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, MoreRegisterAndStackParametersCallee) {
  // Caller
  LinkageLocation location_array1[] = {RegisterLocation(0)};
  LocationSignature locations1(1, 0, location_array1);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LinkageLocation location_array2[] = {RegisterLocation(0), RegisterLocation(0),
                                       RegisterLocation(1), StackLocation(1)};
  LocationSignature locations2(1, 3, location_array2);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);

  CommonOperatorBuilder common(zone());
  const Operator* op = common.Call(desc2);
  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  // We might need to add padding slots to the callee arguments.
  int expected = 1 + ArgumentPaddingSlots(1);
  EXPECT_EQ(expected, stack_param_delta);
}


TEST_F(LinkageTailCall, MoreRegisterAndStackParametersCaller) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0), RegisterLocation(0),
                                      RegisterLocation(1), StackLocation(1)};
  LocationSignature locations1(1, 3, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LinkageLocation location_array2[] = {RegisterLocation(0)};
  LocationSignature locations2(1, 0, location_array2);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);

  CommonOperatorBuilder common(zone());
  const Operator* op = common.Call(desc2);
  Node* const node = Node::New(zone(), 1, op, 0, nullptr, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  // We might need to drop padding slots from the caller's arguments.
  int expected = -1 - ArgumentPaddingSlots(1);
  EXPECT_EQ(expected, stack_param_delta);
}


TEST_F(LinkageTailCall, MatchingStackParameters) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
                                      StackLocation(2), StackLocation(1)};
  LocationSignature locations1(1, 3, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LocationSignature locations2(1, 3, location_array);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);

  CommonOperatorBuilder common(zone());
  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
  Node* parameters[] = {p0, p1, p2, p3};
  const Operator* op = common.Call(desc2);
  Node* const node =
      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, NonMatchingStackParameters) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
                                      StackLocation(2), StackLocation(1)};
  LocationSignature locations1(1, 3, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LocationSignature locations2(1, 3, location_array);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);

  CommonOperatorBuilder common(zone());
  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
  Node* p2 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
  Node* p3 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
  Node* parameters[] = {p0, p1, p2, p3};
  const Operator* op = common.Call(desc2);
  Node* const node =
      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, MatchingStackParametersExtraCallerRegisters) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
                                      StackLocation(2),    StackLocation(1),
                                      RegisterLocation(0), RegisterLocation(1)};
  LocationSignature locations1(1, 5, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LocationSignature locations2(1, 3, location_array);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);

  CommonOperatorBuilder common(zone());
  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
  Node* parameters[] = {p0, p1, p2, p3};
  const Operator* op = common.Call(desc2);
  Node* const node =
      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, MatchingStackParametersExtraCalleeRegisters) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
                                      StackLocation(2),    StackLocation(1),
                                      RegisterLocation(0), RegisterLocation(1)};
  LocationSignature locations1(1, 3, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LocationSignature locations2(1, 5, location_array);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations1);

  CommonOperatorBuilder common(zone());
  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
  Node* p4 = Node::New(zone(), 0, common.Parameter(3), 0, nullptr, false);
  Node* parameters[] = {p0, p1, p2, p3, p4};
  const Operator* op = common.Call(desc2);
  Node* const node =
      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  EXPECT_EQ(0, stack_param_delta);
}


TEST_F(LinkageTailCall, MatchingStackParametersExtraCallerRegistersAndStack) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
                                      StackLocation(2),    StackLocation(1),
                                      RegisterLocation(0), StackLocation(4)};
  LocationSignature locations1(1, 5, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LocationSignature locations2(1, 3, location_array);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);

  CommonOperatorBuilder common(zone());
  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
  Node* p4 = Node::New(zone(), 0, common.Parameter(3), 0, nullptr, false);
  Node* parameters[] = {p0, p1, p2, p3, p4};
  const Operator* op = common.Call(desc2);
  Node* const node =
      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  // We might need to add padding slots to the callee arguments.
  int expected = ArgumentPaddingSlots(1) - 1;
  EXPECT_EQ(expected, stack_param_delta);
}


TEST_F(LinkageTailCall, MatchingStackParametersExtraCalleeRegistersAndStack) {
  // Caller
  LinkageLocation location_array[] = {RegisterLocation(0), StackLocation(3),
                                      StackLocation(2),    RegisterLocation(0),
                                      RegisterLocation(1), StackLocation(4)};
  LocationSignature locations1(1, 3, location_array);
  CallDescriptor* desc1 = NewStandardCallDescriptor(&locations1);

  // Callee
  LocationSignature locations2(1, 5, location_array);
  CallDescriptor* desc2 = NewStandardCallDescriptor(&locations2);

  CommonOperatorBuilder common(zone());
  Node* p0 = Node::New(zone(), 0, nullptr, 0, nullptr, false);
  Node* p1 = Node::New(zone(), 0, common.Parameter(0), 0, nullptr, false);
  Node* p2 = Node::New(zone(), 0, common.Parameter(1), 0, nullptr, false);
  Node* p3 = Node::New(zone(), 0, common.Parameter(2), 0, nullptr, false);
  Node* p4 = Node::New(zone(), 0, common.Parameter(3), 0, nullptr, false);
  Node* parameters[] = {p0, p1, p2, p3, p4};
  const Operator* op = common.Call(desc2);
  Node* const node =
      Node::New(zone(), 1, op, arraysize(parameters), parameters, false);
  EXPECT_TRUE(desc1->CanTailCall(CallDescriptorOf(node->op())));
  int stack_param_delta = desc2->GetStackParameterDelta(desc1);
  // We might need to drop padding slots from the caller's arguments.
  int expected = 1 - ArgumentPaddingSlots(1);
  EXPECT_EQ(expected, stack_param_delta);
}

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