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v8/test/cctest/compiler/test-code-generator.cc
Karl Schimpf 82ee3bcad0 [wasm] move protected instructions from RelocInfo To FixedArray 
The motivation for this is that it greatly reduces the RelocInfo size.
This also results in a small improvement in compile time.

Note: This CL was based on https://codereview.chromium.org/2651833003,
and basically reverts that CL (but handles code changes and some
minor bugs in previous code).

Bug: chromium:772780
Change-Id: I55dd48d3bddd4b3d1c8eec13791b3ee4c485c604
Reviewed-on: https://chromium-review.googlesource.com/730649
Reviewed-by: Mircea Trofin <mtrofin@chromium.org>
Reviewed-by: Eric Holk <eholk@chromium.org>
Commit-Queue: Karl Schimpf <kschimpf@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48947}
2017-10-25 21:15:49 +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_(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}) {
// 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_isolate(),
environment->main_zone(), Code::STUB),
linkage_(environment->test_descriptor()),
frame_(environment->test_descriptor()->CalculateFixedFrameSize()),
generator_(environment->main_zone(), &frame_, &linkage_,
environment->code(), &info_, 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.
}
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() {
// The environment expects this code to tail-call to it's first parameter
// placed in `kReturnRegister0`.
generator_.AssembleArchInstruction(
Instruction::New(zone_, kArchPrepareTailCall));
InstructionOperand callee[] = {
AllocatedOperand(LocationOperand::REGISTER,
MachineRepresentation::kTagged,
kReturnRegister0.code()),
ImmediateOperand(
ImmediateOperand::INLINE,
V8_TARGET_ARCH_STORES_RETURN_ADDRESS_ON_STACK ? 1 : 0)};
Instruction* tail_call = Instruction::New(zone_, kArchTailCallCodeObject, 0,
nullptr, 2, callee, 0, nullptr);
int first_unused_stack_slot;
if (generator_.GetSlotAboveSPBeforeTailCall(tail_call,
&first_unused_stack_slot)) {
generator_.AssembleTailCallBeforeGap(tail_call, first_unused_stack_slot);
generator_.AssembleTailCallAfterGap(tail_call, first_unused_stack_slot);
}
generator_.AssembleArchInstruction(tail_call);
generator_.FinishCode();
generator_.safepoints()->Emit(generator_.tasm(),
frame_.GetTotalFrameSlotCount());
return generator_.FinalizeCode();
}
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.Finalize();
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.Finalize();
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.Finalize();
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 = Instruction::New(env.main_zone(), kArchNop);
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 = Instruction::New(env.main_zone(), kArchNop);
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 = Instruction::New(env.main_zone(), kArchNop);
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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