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v8/test/cctest/compiler/test-code-generator.cc
Georgia Kouveli 5d10735e18 [arm64] Pad function arguments. 
This patch updates the instruction selector and code generator to pad arguments
for arm64 and drop an even number of slots when dropping the arguments. It also
updates the builtins that handle arguments. These changes need to be made at
the same time.

It also adds some tests for forwarding varargs, as this was affected by the
builtin changes and the existing tests did not catch all issues.

Bug: v8:6644
Change-Id: I81318d1d1c9ab2568f84f2bb868d2a2d4cb56053
Reviewed-on: https://chromium-review.googlesource.com/829933
Commit-Queue: Georgia Kouveli <georgia.kouveli@arm.com>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50259}
2017-12-21 11:05:58 +00:00

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// Copyright 2017 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/assembler-inl.h"
#include "src/base/utils/random-number-generator.h"
#include "src/code-stub-assembler.h"
#include "src/codegen.h"
#include "src/compilation-info.h"
#include "src/compiler/code-generator.h"
#include "src/compiler/instruction.h"
#include "src/compiler/linkage.h"
#include "src/isolate.h"
#include "src/objects-inl.h"
#include "test/cctest/cctest.h"
#include "test/cctest/compiler/code-assembler-tester.h"
#include "test/cctest/compiler/function-tester.h"
namespace v8 {
namespace internal {
namespace compiler {
#define __ assembler.
namespace {
int GetSlotSizeInBytes(MachineRepresentation rep) {
switch (rep) {
case MachineRepresentation::kTagged:
case MachineRepresentation::kFloat32:
return kPointerSize;
case MachineRepresentation::kFloat64:
return kDoubleSize;
case MachineRepresentation::kSimd128:
return kSimd128Size;
default:
break;
}
UNREACHABLE();
}
// Forward declaration.
Handle<Code> BuildTeardownFunction(Isolate* isolate, CallDescriptor* descriptor,
std::vector<AllocatedOperand> parameters);
// Build the `setup` function. It takes a code object and a FixedArray as
// parameters and calls the former while passing it each element of the array as
// arguments:
// ~~~
// FixedArray setup(CodeObject* test, FixedArray state_in) {
// // `test` will tail-call to its first parameter which will be `teardown`.
// return test(teardown, state_in[0], state_in[1], state_in[2], ...);
// }
// ~~~
//
// This function needs to convert each element of the FixedArray to raw unboxed
// values to pass to the `test` function. The array will have been created using
// `GenerateInitialState()` and needs to be converted in the following way:
//
// | Parameter type | FixedArray element | Conversion |
// |----------------+--------------------+------------------------------------|
// | kTagged | Smi | None. |
// | kFloat32 | HeapNumber | Load value and convert to Float32. |
// | kFloat64 | HeapNumber | Load value. |
//
Handle<Code> BuildSetupFunction(Isolate* isolate, CallDescriptor* descriptor,
std::vector<AllocatedOperand> parameters) {
CodeAssemblerTester tester(isolate, 2);
CodeStubAssembler assembler(tester.state());
std::vector<Node*> params;
// The first parameter is always the callee.
params.push_back(__ Parameter(0));
params.push_back(
__ HeapConstant(BuildTeardownFunction(isolate, descriptor, parameters)));
Node* state_in = __ Parameter(1);
for (int i = 0; i < static_cast<int>(parameters.size()); i++) {
Node* element = __ LoadFixedArrayElement(state_in, __ IntPtrConstant(i));
// Unbox all elements before passing them as arguments.
switch (parameters[i].representation()) {
// Tagged parameters are Smis, they do not need unboxing.
case MachineRepresentation::kTagged:
break;
case MachineRepresentation::kFloat32:
element = __ TruncateFloat64ToFloat32(__ LoadHeapNumberValue(element));
break;
case MachineRepresentation::kFloat64:
element = __ LoadHeapNumberValue(element);
break;
default:
UNREACHABLE();
break;
}
params.push_back(element);
}
__ Return(tester.raw_assembler_for_testing()->AddNode(
tester.raw_assembler_for_testing()->common()->Call(descriptor),
static_cast<int>(params.size()), params.data()));
return tester.GenerateCodeCloseAndEscape();
}
// Build the `teardown` function. It allocates and fills a FixedArray with all
// its parameters. The parameters need to be consistent with `parameters`.
// ~~~
// FixedArray teardown(CodeObject* /* unused */,
// // Tagged registers.
// Object* r0, Object* r1, ...,
// // FP registers.
// Float32 s0, Float64 d1, ...,
// // Mixed stack slots.
// Float64 mem0, Object* mem1, Float32 mem2, ...) {
// return new FixedArray(r0, r1, ..., s0, d1, ..., mem0, mem1, mem2, ...);
// }
// ~~~
//
// This function needs to convert its parameters into values fit for a
// FixedArray, essentially reverting what the `setup` function did:
//
// | Parameter type | Parameter value | Conversion |
// |----------------+-------------------+----------------------------|
// | kTagged | Smi or HeapNumber | None. |
// | kFloat32 | Raw Float32 | Convert to Float64 and |
// | | | allocate a new HeapNumber. |
// | kFloat64 | Raw Float64 | Allocate a new HeapNumber. |
//
// Note that it is possible for a `kTagged` value to go from a Smi to a
// HeapNumber. This is because `AssembleMove` will allocate a new HeapNumber if
// it is asked to move a FP constant to a tagged register or slot.
//
Handle<Code> BuildTeardownFunction(Isolate* isolate, CallDescriptor* descriptor,
std::vector<AllocatedOperand> parameters) {
CodeAssemblerTester tester(isolate, descriptor);
CodeStubAssembler assembler(tester.state());
Node* result_array = __ AllocateFixedArray(
PACKED_ELEMENTS, __ IntPtrConstant(parameters.size()));
for (int i = 0; i < static_cast<int>(parameters.size()); i++) {
// The first argument is not used.
Node* param = __ Parameter(i + 1);
switch (parameters[i].representation()) {
case MachineRepresentation::kTagged:
break;
// Box FP values into HeapNumbers.
case MachineRepresentation::kFloat32:
param =
tester.raw_assembler_for_testing()->ChangeFloat32ToFloat64(param);
// Fallthrough
case MachineRepresentation::kFloat64:
param = __ AllocateHeapNumberWithValue(param);
break;
default:
UNREACHABLE();
break;
}
__ StoreFixedArrayElement(result_array, i, param);
}
__ Return(result_array);
return tester.GenerateCodeCloseAndEscape();
}
// Print the content of `value`, representing the register or stack slot
// described by `operand`.
void PrintStateValue(std::ostream& os, Handle<Object> value,
AllocatedOperand operand) {
switch (operand.representation()) {
case MachineRepresentation::kTagged:
if (value->IsSmi()) {
os << Smi::cast(*value)->value();
} else {
os << value->Number();
}
break;
case MachineRepresentation::kFloat32:
case MachineRepresentation::kFloat64:
os << value->Number();
break;
default:
UNREACHABLE();
break;
}
os << " (" << operand.representation() << " ";
if (operand.location_kind() == AllocatedOperand::REGISTER) {
os << "register";
} else {
DCHECK_EQ(operand.location_kind(), AllocatedOperand::STACK_SLOT);
os << "stack slot";
}
os << ")";
}
} // namespace
#undef __
// Representation of a test environment. It describes a set of registers, stack
// slots and constants available to the CodeGeneratorTester to perform moves
// with. It has the ability to randomly generate lists of moves and run the code
// generated by the CodeGeneratorTester.
//
// At the moment, only the following representations are tested:
// - kTagged
// - kFloat32
// - kFloat64
// - TODO(planglois): Add support for kSimd128.
// There is no need to test using Word32 or Word64 as they are the same as
// Tagged as far as the code generator is concerned.
//
// Testing the generated code is achieved by wrapping it around `setup` and
// `teardown` functions, written using the CodeStubAssembler. The key idea here
// is that `teardown` and the generated code share the same custom
// CallDescriptor. This descriptor assigns parameters to either registers or
// stack slot of a given representation and therefore essentially describes the
// environment.
//
// What happens is the following:
//
// - The `setup` function receives a FixedArray as the initial state. It
// unpacks it and passes each element as arguments to the generated code
// `test`. We also pass the `teardown` function as a first argument. Thanks
// to the custom CallDescriptor, registers and stack slots get initialised
// according to the content of the FixedArray.
//
// - The `test` function performs the list of moves on its parameters and
// eventually tail-calls to its first parameter, which is the `teardown`
// function.
//
// - The `teardown` function allocates a new FixedArray and fills it with all
// its parameters. Thanks to the tail-call, this is as if the `setup`
// function called `teardown` directly, except now moves were performed!
//
// .----------------setup--------------------------.
// | Take a FixedArray as parameters with |
// | all the initial values of registers |
// | and stack slots. | <- CodeStubAssembler
// | |
// | Call test(teardown, state[0], state[1], ...); |
// '-----------------------------------------------'
// |
// V
// .----------------test-----------------------------.
// | - Move(param3, param42); |
// | - Swap(param64, param1); |
// | - Move(param2, param6); | <- CodeGeneratorTester
// | ... |
// | |
// | // "teardown" is the first parameter as well as |
// | // the callee. |
// | TailCall param0(param0, param1, param2, ...); |
// '-------------------------------------------------'
// |
// V
// .----------------teardown--------------.
// | Create a FixedArray with all |
// | parameters and return it. | <- CodeStubAssembler
// '--------------------------------------'
class TestEnvironment : public HandleAndZoneScope {
public:
// These constants may be tuned to experiment with different environments.
static constexpr int kGeneralRegisterCount = 4;
static constexpr int kDoubleRegisterCount = 6;
static constexpr int kTaggedSlotCount = 64;
static constexpr int kFloat32SlotCount = 64;
static constexpr int kFloat64SlotCount = 64;
static constexpr int kStackParameterCount =
kTaggedSlotCount + kFloat32SlotCount + kFloat64SlotCount;
// TODO(all): Test all types of constants (e.g. ExternalReference and
// HeapObject).
static constexpr int kSmiConstantCount = 4;
static constexpr int kFloatConstantCount = 4;
static constexpr int kDoubleConstantCount = 4;
TestEnvironment()
: blocks_(1, main_zone()),
code_(main_isolate(), main_zone(), &blocks_),
rng_(CcTest::random_number_generator()),
// TODO(planglois): Support kSimd128.
supported_reps_({MachineRepresentation::kTagged,
MachineRepresentation::kFloat32,
MachineRepresentation::kFloat64}) {
// Create and initialize a single empty block in blocks_.
InstructionBlock* block = new (main_zone()) InstructionBlock(
main_zone(), RpoNumber::FromInt(0), RpoNumber::Invalid(),
RpoNumber::Invalid(), false, false);
block->set_ao_number(RpoNumber::FromInt(0));
blocks_[0] = block;
// The "teardown" and "test" functions share the same descriptor with the
// following signature:
// ~~~
// FixedArray f(CodeObject* teardown,
// // Tagged registers.
// Object*, Object*, ...,
// // FP registers.
// Float32, Float64, ...,
// // Mixed stack slots.
// Float64, Object*, Float32, ...);
// ~~~
LocationSignature::Builder test_signature(main_zone(), 1,
1 + kGeneralRegisterCount +
kDoubleRegisterCount +
kStackParameterCount);
// The first parameter will be the code object of the "teardown"
// function. This way, the "test" function can tail-call to it.
test_signature.AddParam(LinkageLocation::ForRegister(
kReturnRegister0.code(), MachineType::AnyTagged()));
// Initialise registers.
int32_t general_mask =
RegisterConfiguration::Default()->allocatable_general_codes_mask();
// kReturnRegister0 is used to hold the "teardown" code object, do not
// generate moves using it.
std::unique_ptr<const RegisterConfiguration> registers(
RegisterConfiguration::RestrictGeneralRegisters(
general_mask & ~(1 << kReturnRegister0.code())));
for (int i = 0; i < kGeneralRegisterCount; i++) {
int code = registers->GetAllocatableGeneralCode(i);
AddRegister(&test_signature, MachineRepresentation::kTagged, code);
}
// We assume that Double and Float registers alias, depending on
// kSimpleFPAliasing. For this reason, we allocate a Float and a Double in
// pairs.
static_assert((kDoubleRegisterCount % 2) == 0,
"kDoubleRegisterCount should be a multiple of two.");
for (int i = 0; i < kDoubleRegisterCount; i += 2) {
// Make sure we do not allocate FP registers which alias. We double the
// index for Float registers if the aliasing is not "Simple":
// Simple -> s0, d1, s2, d3, s4, d5, ...
// Arm32-style -> s0, d1, s4, d3, s8, d5, ...
// This isn't space-efficient at all but suits our need.
static_assert(kDoubleRegisterCount < 16,
"Arm has a d16 register but no overlapping s32 register.");
int float_code =
registers->GetAllocatableFloatCode(kSimpleFPAliasing ? i : i * 2);
int double_code = registers->GetAllocatableDoubleCode(i + 1);
AddRegister(&test_signature, MachineRepresentation::kFloat32, float_code);
AddRegister(&test_signature, MachineRepresentation::kFloat64,
double_code);
}
// Initialise stack slots.
// Stack parameters start at -1.
int slot_parameter_n = -1;
// TODO(planglois): Support kSimd128 stack slots.
std::map<MachineRepresentation, int> slots = {
{MachineRepresentation::kTagged, kTaggedSlotCount},
{MachineRepresentation::kFloat32, kFloat32SlotCount},
{MachineRepresentation::kFloat64, kFloat64SlotCount}};
// Allocate new slots until we run out of them.
while (std::any_of(slots.cbegin(), slots.cend(),
[](const std::pair<MachineRepresentation, int>& entry) {
// True if there are slots left to allocate for this
// representation.
return entry.second > 0;
})) {
// Pick a random MachineRepresentation from supported_reps_.
MachineRepresentation rep = CreateRandomMachineRepresentation();
auto entry = slots.find(rep);
DCHECK(entry != slots.end());
// We may have picked a representation for which all slots have already
// been allocated.
if (entry->second > 0) {
// Keep a map of (MachineRepresentation . std::vector<int>) with
// allocated slots to pick from for each representation.
int slot = slot_parameter_n;
slot_parameter_n -= (GetSlotSizeInBytes(rep) / kPointerSize);
AddStackSlot(&test_signature, rep, slot);
entry->second--;
}
}
// Initialise random constants.
// While constants do not know about Smis, we need to be able to
// differentiate between a pointer to a HeapNumber and a integer. For this
// reason, we make sure all integers are Smis, including constants.
for (int i = 0; i < kSmiConstantCount; i++) {
intptr_t smi_value = reinterpret_cast<intptr_t>(
Smi::FromInt(rng_->NextInt(Smi::kMaxValue)));
Constant constant = kPointerSize == 8
? Constant(static_cast<int64_t>(smi_value))
: Constant(static_cast<int32_t>(smi_value));
AddConstant(MachineRepresentation::kTagged, AllocateConstant(constant));
}
// Float and Double constants can be moved to both Tagged and FP registers
// or slots. Register them as compatible with both FP and Tagged
// destinations.
for (int i = 0; i < kFloatConstantCount; i++) {
int virtual_register =
AllocateConstant(Constant(DoubleToFloat32(rng_->NextDouble())));
AddConstant(MachineRepresentation::kTagged, virtual_register);
AddConstant(MachineRepresentation::kFloat32, virtual_register);
}
for (int i = 0; i < kDoubleConstantCount; i++) {
int virtual_register = AllocateConstant(Constant(rng_->NextDouble()));
AddConstant(MachineRepresentation::kTagged, virtual_register);
AddConstant(MachineRepresentation::kFloat64, virtual_register);
}
// The "teardown" function returns a FixedArray with the resulting state.
test_signature.AddReturn(LinkageLocation::ForRegister(
kReturnRegister0.code(), MachineType::AnyTagged()));
test_descriptor_ = new (main_zone())
CallDescriptor(CallDescriptor::kCallCodeObject, // kind
MachineType::AnyTagged(), // target MachineType
LinkageLocation::ForAnyRegister(
MachineType::AnyTagged()), // target location
test_signature.Build(), // location_sig
kStackParameterCount, // stack_parameter_count
Operator::kNoProperties, // properties
kNoCalleeSaved, // callee-saved registers
kNoCalleeSaved, // callee-saved fp
CallDescriptor::kNoFlags); // flags
}
int AllocateConstant(Constant constant) {
int virtual_register = code_.NextVirtualRegister();
code_.AddConstant(virtual_register, constant);
return virtual_register;
}
// Register a constant referenced by `virtual_register` as compatible with
// `rep`.
void AddConstant(MachineRepresentation rep, int virtual_register) {
auto entry = allocated_constants_.find(rep);
if (entry == allocated_constants_.end()) {
allocated_constants_.emplace(
rep, std::vector<ConstantOperand>{ConstantOperand(virtual_register)});
} else {
entry->second.emplace_back(virtual_register);
}
}
// Register a new register or stack slot as compatible with `rep`. As opposed
// to constants, registers and stack slots are written to on `setup` and read
// from on `teardown`. Therefore they are part of the environment's layout,
// and are parameters of the `test` function.
void AddRegister(LocationSignature::Builder* test_signature,
MachineRepresentation rep, int code) {
AllocatedOperand operand(AllocatedOperand::REGISTER, rep, code);
layout_.push_back(operand);
test_signature->AddParam(LinkageLocation::ForRegister(
code, MachineType::TypeForRepresentation(rep)));
auto entry = allocated_registers_.find(rep);
if (entry == allocated_registers_.end()) {
allocated_registers_.emplace(rep, std::vector<AllocatedOperand>{operand});
} else {
entry->second.push_back(operand);
}
}
void AddStackSlot(LocationSignature::Builder* test_signature,
MachineRepresentation rep, int slot) {
AllocatedOperand operand(AllocatedOperand::STACK_SLOT, rep, slot);
layout_.push_back(operand);
test_signature->AddParam(LinkageLocation::ForCallerFrameSlot(
slot, MachineType::TypeForRepresentation(rep)));
auto entry = allocated_slots_.find(rep);
if (entry == allocated_slots_.end()) {
allocated_slots_.emplace(rep, std::vector<AllocatedOperand>{operand});
} else {
entry->second.push_back(operand);
}
}
// Generate a random initial state to test moves against. A "state" is a
// packed FixedArray with Smis and HeapNumbers, according to the layout of the
// environment.
Handle<FixedArray> GenerateInitialState() {
Handle<FixedArray> state = main_isolate()->factory()->NewFixedArray(
static_cast<int>(layout_.size()));
for (int i = 0; i < state->length(); i++) {
switch (layout_[i].representation()) {
case MachineRepresentation::kTagged:
state->set(i, Smi::FromInt(rng_->NextInt(Smi::kMaxValue)));
break;
case MachineRepresentation::kFloat32:
// HeapNumbers are Float64 values. However, we will convert it to a
// Float32 and back inside `setup` and `teardown`. Make sure the value
// we pick fits in a Float32.
state->set(
i, *main_isolate()->factory()->NewHeapNumber(
static_cast<double>(DoubleToFloat32(rng_->NextDouble()))));
break;
case MachineRepresentation::kFloat64:
state->set(
i, *main_isolate()->factory()->NewHeapNumber(rng_->NextDouble()));
break;
default:
UNREACHABLE();
break;
}
}
return state;
}
// Run the code generated by a CodeGeneratorTester against `state_in` and
// return a new resulting state.
Handle<FixedArray> Run(Handle<Code> test, Handle<FixedArray> state_in) {
Handle<FixedArray> state_out = main_isolate()->factory()->NewFixedArray(
static_cast<int>(layout_.size()));
{
Handle<Code> setup =
BuildSetupFunction(main_isolate(), test_descriptor_, layout_);
// FunctionTester maintains its own HandleScope which means that its
// return value will be freed along with it. Copy the result into
// state_out.
FunctionTester ft(setup, 2);
Handle<FixedArray> result = ft.CallChecked<FixedArray>(test, state_in);
CHECK_EQ(result->length(), state_in->length());
result->CopyTo(0, *state_out, 0, result->length());
}
return state_out;
}
// For a given operand representing either a register or a stack slot, return
// what position it should live in inside a FixedArray state.
int OperandToStatePosition(const AllocatedOperand& operand) const {
// Search `layout_` for `operand`.
auto it = std::find_if(layout_.cbegin(), layout_.cend(),
[operand](const AllocatedOperand& this_operand) {
return this_operand.Equals(operand);
});
DCHECK_NE(it, layout_.cend());
return static_cast<int>(std::distance(layout_.cbegin(), it));
}
// Perform the given list of moves on `state_in` and return a newly allocated
// state with the results.
Handle<FixedArray> SimulateMoves(ParallelMove* moves,
Handle<FixedArray> state_in) {
Handle<FixedArray> state_out = main_isolate()->factory()->NewFixedArray(
static_cast<int>(layout_.size()));
// We do not want to modify `state_in` in place so perform the moves on a
// copy.
state_in->CopyTo(0, *state_out, 0, state_in->length());
for (auto move : *moves) {
int to_index =
OperandToStatePosition(AllocatedOperand::cast(move->destination()));
InstructionOperand from = move->source();
if (from.IsConstant()) {
Constant constant =
code_.GetConstant(ConstantOperand::cast(from).virtual_register());
Handle<Object> constant_value;
switch (constant.type()) {
case Constant::kInt32:
constant_value =
Handle<Smi>(reinterpret_cast<Smi*>(
static_cast<intptr_t>(constant.ToInt32())),
main_isolate());
break;
case Constant::kInt64:
constant_value =
Handle<Smi>(reinterpret_cast<Smi*>(
static_cast<intptr_t>(constant.ToInt64())),
main_isolate());
break;
case Constant::kFloat32:
constant_value = main_isolate()->factory()->NewHeapNumber(
static_cast<double>(constant.ToFloat32()));
break;
case Constant::kFloat64:
constant_value = main_isolate()->factory()->NewHeapNumber(
constant.ToFloat64().value());
break;
default:
UNREACHABLE();
break;
}
state_out->set(to_index, *constant_value);
} else {
int from_index = OperandToStatePosition(AllocatedOperand::cast(from));
state_out->set(to_index, *state_out->GetValueChecked<Object>(
main_isolate(), from_index));
}
}
return state_out;
}
// Perform the given list of swaps on `state_in` and return a newly allocated
// state with the results.
Handle<FixedArray> SimulateSwaps(ParallelMove* swaps,
Handle<FixedArray> state_in) {
Handle<FixedArray> state_out = main_isolate()->factory()->NewFixedArray(
static_cast<int>(layout_.size()));
// We do not want to modify `state_in` in place so perform the swaps on a
// copy.
state_in->CopyTo(0, *state_out, 0, state_in->length());
for (auto swap : *swaps) {
int lhs_index =
OperandToStatePosition(AllocatedOperand::cast(swap->destination()));
int rhs_index =
OperandToStatePosition(AllocatedOperand::cast(swap->source()));
Handle<Object> lhs =
state_out->GetValueChecked<Object>(main_isolate(), lhs_index);
Handle<Object> rhs =
state_out->GetValueChecked<Object>(main_isolate(), rhs_index);
state_out->set(lhs_index, *rhs);
state_out->set(rhs_index, *lhs);
}
return state_out;
}
// Compare the given state with a reference.
void CheckState(Handle<FixedArray> actual, Handle<FixedArray> expected) {
for (int i = 0; i < static_cast<int>(layout_.size()); i++) {
Handle<Object> actual_value =
actual->GetValueChecked<Object>(main_isolate(), i);
Handle<Object> expected_value =
expected->GetValueChecked<Object>(main_isolate(), i);
if (!actual_value->StrictEquals(*expected_value)) {
std::ostringstream expected_str;
PrintStateValue(expected_str, expected_value, layout_[i]);
std::ostringstream actual_str;
PrintStateValue(actual_str, actual_value, layout_[i]);
V8_Fatal(__FILE__, __LINE__, "Expected: '%s' but got '%s'",
expected_str.str().c_str(), actual_str.str().c_str());
}
}
}
enum OperandConstraint {
kNone,
// Restrict operands to non-constants. This is useful when generating a
// destination.
kCannotBeConstant
};
// Generate parallel moves at random. Note that they may not be compatible
// between each other as this doesn't matter to the code generator.
ParallelMove* GenerateRandomMoves(int size) {
ParallelMove* parallel_move = new (main_zone()) ParallelMove(main_zone());
for (int i = 0; i < size;) {
MachineRepresentation rep = CreateRandomMachineRepresentation();
MoveOperands mo(CreateRandomOperand(kNone, rep),
CreateRandomOperand(kCannotBeConstant, rep));
// It isn't valid to call `AssembleMove` and `AssembleSwap` with redundant
// moves.
if (mo.IsRedundant()) continue;
parallel_move->AddMove(mo.source(), mo.destination());
// Iterate only when a move was created.
i++;
}
return parallel_move;
}
ParallelMove* GenerateRandomSwaps(int size) {
ParallelMove* parallel_move = new (main_zone()) ParallelMove(main_zone());
for (int i = 0; i < size;) {
MachineRepresentation rep = CreateRandomMachineRepresentation();
InstructionOperand lhs = CreateRandomOperand(kCannotBeConstant, rep);
InstructionOperand rhs = CreateRandomOperand(kCannotBeConstant, rep);
MoveOperands mo(lhs, rhs);
// It isn't valid to call `AssembleMove` and `AssembleSwap` with redundant
// moves.
if (mo.IsRedundant()) continue;
// Canonicalize the swap: the register operand has to be the left hand
// side.
if (lhs.IsStackSlot() || lhs.IsFPStackSlot()) {
std::swap(lhs, rhs);
}
parallel_move->AddMove(lhs, rhs);
// Iterate only when a swap was created.
i++;
}
return parallel_move;
}
MachineRepresentation CreateRandomMachineRepresentation() {
int index = rng_->NextInt(static_cast<int>(supported_reps_.size()));
return supported_reps_[index];
}
InstructionOperand CreateRandomOperand(OperandConstraint constraint,
MachineRepresentation rep) {
// Only generate a Constant if the operand is a source and we have a
// constant with a compatible representation in stock.
bool generate_constant =
(constraint != kCannotBeConstant) &&
(allocated_constants_.find(rep) != allocated_constants_.end());
switch (rng_->NextInt(generate_constant ? 3 : 2)) {
case 0:
return CreateRandomStackSlotOperand(rep);
case 1:
return CreateRandomRegisterOperand(rep);
case 2:
return CreateRandomConstant(rep);
}
UNREACHABLE();
}
AllocatedOperand CreateRandomRegisterOperand(MachineRepresentation rep) {
int index =
rng_->NextInt(static_cast<int>(allocated_registers_[rep].size()));
return allocated_registers_[rep][index];
}
AllocatedOperand CreateRandomStackSlotOperand(MachineRepresentation rep) {
int index = rng_->NextInt(static_cast<int>(allocated_slots_[rep].size()));
return allocated_slots_[rep][index];
}
ConstantOperand CreateRandomConstant(MachineRepresentation rep) {
int index =
rng_->NextInt(static_cast<int>(allocated_constants_[rep].size()));
return allocated_constants_[rep][index];
}
v8::base::RandomNumberGenerator* rng() const { return rng_; }
InstructionSequence* code() { return &code_; }
CallDescriptor* test_descriptor() { return test_descriptor_; }
private:
ZoneVector<InstructionBlock*> blocks_;
InstructionSequence code_;
v8::base::RandomNumberGenerator* rng_;
// The layout describes the type of each element in the environment, in order.
std::vector<AllocatedOperand> layout_;
CallDescriptor* test_descriptor_;
// Allocated constants, registers and stack slots that we can generate moves
// with. Each per compatible representation.
std::vector<MachineRepresentation> supported_reps_;
std::map<MachineRepresentation, std::vector<ConstantOperand>>
allocated_constants_;
std::map<MachineRepresentation, std::vector<AllocatedOperand>>
allocated_registers_;
std::map<MachineRepresentation, std::vector<AllocatedOperand>>
allocated_slots_;
};
// static
constexpr int TestEnvironment::kGeneralRegisterCount;
constexpr int TestEnvironment::kDoubleRegisterCount;
constexpr int TestEnvironment::kTaggedSlotCount;
constexpr int TestEnvironment::kFloat32SlotCount;
constexpr int TestEnvironment::kFloat64SlotCount;
constexpr int TestEnvironment::kStackParameterCount;
constexpr int TestEnvironment::kSmiConstantCount;
constexpr int TestEnvironment::kFloatConstantCount;
constexpr int TestEnvironment::kDoubleConstantCount;
// Wrapper around the CodeGenerator. Code generated by this can only be called
// using the given `TestEnvironment`.
//
// TODO(planglois): We execute moves on stack parameters only which restricts
// ourselves to small positive offsets relative to the frame pointer. We should
// test large and negative offsets too. A way to do this would be to move some
// stack parameters to local spill slots and create artificial stack space
// between them.
class CodeGeneratorTester {
public:
explicit CodeGeneratorTester(TestEnvironment* environment)
: zone_(environment->main_zone()),
info_(ArrayVector("test"), environment->main_zone(), Code::STUB),
linkage_(environment->test_descriptor()),
frame_(environment->test_descriptor()->CalculateFixedFrameSize()),
generator_(environment->main_zone(), &frame_, &linkage_,
environment->code(), &info_, environment->main_isolate(),
base::Optional<OsrHelper>(), kNoSourcePosition, nullptr,
nullptr) {
// Force a frame to be created.
generator_.frame_access_state()->MarkHasFrame(true);
generator_.AssembleConstructFrame();
// TODO(all): Generate a stack check here so that we fail gracefully if the
// frame is too big.
}
Instruction* CreateTailCall(int stack_slot_delta) {
int optional_padding_slot = stack_slot_delta;
InstructionOperand callee[] = {
ImmediateOperand(ImmediateOperand::INLINE, optional_padding_slot),
ImmediateOperand(ImmediateOperand::INLINE, stack_slot_delta)};
Instruction* tail_call = Instruction::New(zone_, kArchTailCallCodeObject, 0,
nullptr, 2, callee, 0, nullptr);
return tail_call;
}
enum PushTypeFlag {
kRegisterPush = CodeGenerator::kRegisterPush,
kStackSlotPush = CodeGenerator::kStackSlotPush,
kScalarPush = CodeGenerator::kScalarPush
};
void CheckAssembleTailCallGaps(Instruction* instr,
int first_unused_stack_slot,
CodeGeneratorTester::PushTypeFlag push_type) {
generator_.AssembleTailCallBeforeGap(instr, first_unused_stack_slot);
#if defined(V8_TARGET_ARCH_ARM) || defined(V8_TARGET_ARCH_S390) || \
defined(V8_TARGET_ARCH_PPC)
// Only folding register pushes is supported on ARM.
bool supported = ((push_type & CodeGenerator::kRegisterPush) == push_type);
#elif defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_IA32) || \
defined(V8_TARGET_ARCH_X87)
bool supported = ((push_type & CodeGenerator::kScalarPush) == push_type);
#else
bool supported = false;
#endif
if (supported) {
// Architectures supporting folding adjacent pushes should now have
// resolved all moves.
for (const auto& move :
*instr->parallel_moves()[Instruction::FIRST_GAP_POSITION]) {
CHECK(move->IsEliminated());
}
}
generator_.AssembleGaps(instr);
generator_.AssembleTailCallAfterGap(instr, first_unused_stack_slot);
}
void CheckAssembleMove(InstructionOperand* source,
InstructionOperand* destination) {
int start = generator_.tasm()->pc_offset();
generator_.AssembleMove(source, destination);
CHECK(generator_.tasm()->pc_offset() > start);
}
void CheckAssembleSwap(InstructionOperand* source,
InstructionOperand* destination) {
int start = generator_.tasm()->pc_offset();
generator_.AssembleSwap(source, destination);
CHECK(generator_.tasm()->pc_offset() > start);
}
Handle<Code> Finalize() {
generator_.FinishCode();
generator_.safepoints()->Emit(generator_.tasm(),
frame_.GetTotalFrameSlotCount());
return generator_.FinalizeCode();
}
Handle<Code> FinalizeForExecuting() {
InstructionSequence* sequence = generator_.code();
sequence->StartBlock(RpoNumber::FromInt(0));
// The environment expects this code to tail-call to it's first parameter
// placed in `kReturnRegister0`.
sequence->AddInstruction(Instruction::New(zone_, kArchPrepareTailCall));
// We use either zero or one slots.
int first_unused_stack_slot =
V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK ? 1 : 0;
int optional_padding_slot = first_unused_stack_slot;
InstructionOperand callee[] = {
AllocatedOperand(LocationOperand::REGISTER,
MachineRepresentation::kTagged,
kReturnRegister0.code()),
ImmediateOperand(ImmediateOperand::INLINE, optional_padding_slot),
ImmediateOperand(ImmediateOperand::INLINE, first_unused_stack_slot)};
Instruction* tail_call = Instruction::New(zone_, kArchTailCallCodeObject, 0,
nullptr, 3, callee, 0, nullptr);
sequence->AddInstruction(tail_call);
sequence->EndBlock(RpoNumber::FromInt(0));
generator_.AssembleBlock(
sequence->InstructionBlockAt(RpoNumber::FromInt(0)));
return Finalize();
}
private:
Zone* zone_;
CompilationInfo info_;
Linkage linkage_;
Frame frame_;
CodeGenerator generator_;
};
// The following fuzz tests will assemble a lot of moves, wrap them in
// executable native code and run them. In order to check that moves were
// performed correctly, we need to setup an environment with an initial state
// and get it back after the list of moves were performed.
//
// We have two components to do this: TestEnvironment and CodeGeneratorTester.
//
// The TestEnvironment is in charge of bringing up an environment consisting of
// a set of registers, stack slots and constants, with initial values in
// them. The CodeGeneratorTester is a wrapper around the CodeGenerator and its
// only purpose is to generate code for a list of moves. The TestEnvironment is
// then able to run this code against the environment and return a resulting
// state.
//
// A "state" here is a packed FixedArray with tagged values which can either be
// Smis or HeapNumbers. When calling TestEnvironment::Run(...), registers and
// stack slots will be initialised according to this FixedArray. A new
// FixedArray is returned containing values that were moved by the generated
// code.
//
// And finally, we are able to compare the resulting FixedArray against a
// reference, computed with a simulation of AssembleMove and AssembleSwap. See
// SimulateMoves and SimulateSwaps.
TEST(FuzzAssembleMove) {
TestEnvironment env;
CodeGeneratorTester c(&env);
Handle<FixedArray> state_in = env.GenerateInitialState();
ParallelMove* moves = env.GenerateRandomMoves(1000);
for (auto m : *moves) {
c.CheckAssembleMove(&m->source(), &m->destination());
}
Handle<Code> test = c.FinalizeForExecuting();
if (FLAG_print_code) {
test->Print();
}
Handle<FixedArray> actual = env.Run(test, state_in);
Handle<FixedArray> expected = env.SimulateMoves(moves, state_in);
env.CheckState(actual, expected);
}
TEST(FuzzAssembleSwap) {
TestEnvironment env;
CodeGeneratorTester c(&env);
Handle<FixedArray> state_in = env.GenerateInitialState();
ParallelMove* swaps = env.GenerateRandomSwaps(1000);
for (auto s : *swaps) {
c.CheckAssembleSwap(&s->source(), &s->destination());
}
Handle<Code> test = c.FinalizeForExecuting();
if (FLAG_print_code) {
test->Print();
}
Handle<FixedArray> actual = env.Run(test, state_in);
Handle<FixedArray> expected = env.SimulateSwaps(swaps, state_in);
env.CheckState(actual, expected);
}
TEST(FuzzAssembleMoveAndSwap) {
TestEnvironment env;
CodeGeneratorTester c(&env);
Handle<FixedArray> state_in = env.GenerateInitialState();
Handle<FixedArray> expected =
env.main_isolate()->factory()->NewFixedArray(state_in->length());
state_in->CopyTo(0, *expected, 0, state_in->length());
for (int i = 0; i < 1000; i++) {
// Randomly alternate between swaps and moves.
if (env.rng()->NextInt(2) == 0) {
ParallelMove* move = env.GenerateRandomMoves(1);
expected = env.SimulateMoves(move, expected);
c.CheckAssembleMove(&move->at(0)->source(), &move->at(0)->destination());
} else {
ParallelMove* swap = env.GenerateRandomSwaps(1);
expected = env.SimulateSwaps(swap, expected);
c.CheckAssembleSwap(&swap->at(0)->source(), &swap->at(0)->destination());
}
}
Handle<Code> test = c.FinalizeForExecuting();
if (FLAG_print_code) {
test->Print();
}
Handle<FixedArray> actual = env.Run(test, state_in);
env.CheckState(actual, expected);
}
TEST(AssembleTailCallGap) {
const RegisterConfiguration* conf = RegisterConfiguration::Default();
TestEnvironment env;
// This test assumes at least 4 registers are allocatable.
CHECK_LE(4, conf->num_allocatable_general_registers());
auto r0 = AllocatedOperand(LocationOperand::REGISTER,
MachineRepresentation::kTagged,
conf->GetAllocatableGeneralCode(0));
auto r1 = AllocatedOperand(LocationOperand::REGISTER,
MachineRepresentation::kTagged,
conf->GetAllocatableGeneralCode(1));
auto r2 = AllocatedOperand(LocationOperand::REGISTER,
MachineRepresentation::kTagged,
conf->GetAllocatableGeneralCode(2));
auto r3 = AllocatedOperand(LocationOperand::REGISTER,
MachineRepresentation::kTagged,
conf->GetAllocatableGeneralCode(3));
auto slot_minus_4 = AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, -4);
auto slot_minus_3 = AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, -3);
auto slot_minus_2 = AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, -2);
auto slot_minus_1 = AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, -1);
// Avoid slot 0 for architectures which use it store the return address.
int first_slot = V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK ? 1 : 0;
auto slot_0 = AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, first_slot);
auto slot_1 =
AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, first_slot + 1);
auto slot_2 =
AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, first_slot + 2);
auto slot_3 =
AllocatedOperand(LocationOperand::STACK_SLOT,
MachineRepresentation::kTagged, first_slot + 3);
// These tests all generate series of moves that the code generator should
// detect as adjacent pushes. Depending on the architecture, we make sure
// these moves get eliminated.
// Also, disassembling with `--print-code` is useful when debugging.
{
// Generate a series of register pushes only.
CodeGeneratorTester c(&env);
Instruction* instr = c.CreateTailCall(first_slot + 4);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(r3, slot_0);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(r2, slot_1);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(r1, slot_2);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(r0, slot_3);
c.CheckAssembleTailCallGaps(instr, first_slot + 4,
CodeGeneratorTester::kRegisterPush);
Handle<Code> code = c.Finalize();
if (FLAG_print_code) {
code->Print();
}
}
{
// Generate a series of stack pushes only.
CodeGeneratorTester c(&env);
Instruction* instr = c.CreateTailCall(first_slot + 4);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(slot_minus_4, slot_0);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(slot_minus_3, slot_1);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(slot_minus_2, slot_2);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(slot_minus_1, slot_3);
c.CheckAssembleTailCallGaps(instr, first_slot + 4,
CodeGeneratorTester::kStackSlotPush);
Handle<Code> code = c.Finalize();
if (FLAG_print_code) {
code->Print();
}
}
{
// Generate a mix of stack and register pushes.
CodeGeneratorTester c(&env);
Instruction* instr = c.CreateTailCall(first_slot + 4);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(slot_minus_2, slot_0);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(r1, slot_1);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(slot_minus_1, slot_2);
instr
->GetOrCreateParallelMove(Instruction::FIRST_GAP_POSITION,
env.main_zone())
->AddMove(r0, slot_3);
c.CheckAssembleTailCallGaps(instr, first_slot + 4,
CodeGeneratorTester::kScalarPush);
Handle<Code> code = c.Finalize();
if (FLAG_print_code) {
code->Print();
}
}
}
} // namespace compiler
} // namespace internal
} // namespace v8
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