test-code-generator.cc | Explore in Territory

// 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 <algorithm>
#include <optional>

#include "src/base/utils/random-number-generator.h"
#include "src/codegen/assembler-inl.h"
#include "src/codegen/code-stub-assembler-inl.h"
#include "src/codegen/machine-type.h"
#include "src/codegen/macro-assembler-inl.h"
#include "src/codegen/optimized-compilation-info.h"
#include "src/compiler/backend/code-generator.h"
#include "src/compiler/backend/instruction.h"
#include "src/compiler/linkage.h"
#include "src/execution/isolate.h"
#include "src/objects/heap-number-inl.h"
#include "src/objects/objects-inl.h"
#include "src/objects/smi.h"
#include "test/cctest/cctest.h"
#include "test/cctest/compiler/codegen-tester.h"
#include "test/cctest/compiler/function-tester.h"
#include "test/common/code-assembler-tester.h"

#if V8_ENABLE_WEBASSEMBLY
#include "src/compiler/wasm-compiler.h"
#include "src/wasm/wasm-engine.h"
#endif  // V8_ENABLE_WEBASSEMBLY

namespace v8 {
namespace internal {
namespace compiler {

#define __ …

namespace {

enum MoveMode { … };

// Whether the layout before and after the moves must be the same.
enum LayoutMode { … };
enum OperandLifetime { … };

int GetSlotSizeInBytes(MachineRepresentation rep) { … }

// Forward declaration.
Handle<Code> BuildTeardownFunction(
    Isolate* isolate, CallDescriptor* call_descriptor,
    const 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) {
//   FixedArray state_out = AllocateZeroedFixedArray(state_in.length());
//   // `test` will tail-call to its first parameter which will be `teardown`.
//   return test(teardown, state_out, 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.                        |
// | kSimd128       | FixedArray<Smi>[4]  | Untag each Smi and write the       |
// |                |                     | results into lanes of a new        |
// |                |                     | 128-bit vector.                    |
//
Handle<Code> BuildSetupFunction(Isolate* isolate,
                                CallDescriptor* test_call_descriptor,
                                CallDescriptor* teardown_call_descriptor,
                                std::vector<AllocatedOperand> parameters,
                                const std::vector<AllocatedOperand>& results) { … }

// Build the `teardown` function. It takes a FixedArray as argument, fills it
// with the rest of its parameters and returns it. The parameters need to be
// consistent with `parameters`.
// ~~~
// FixedArray teardown(CodeObject* /* unused  */, FixedArray result,
//                     // Tagged registers.
//                     Object r0, Object r1, ...,
//                     // FP registers.
//                     Float32 s0, Float64 d1, ...,
//                     // Mixed stack slots.
//                     Float64 mem0, Object mem1, Float32 mem2, ...) {
//   result[0] = r0;
//   result[1] = r1;
//   ...
//   result[..] = s0;
//   ...
//   result[..] = mem0;
//   ...
//   return result;
// }
// ~~~
//
// 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.                  |
// | kFloat64       | Raw Float64       | None.                                |
// | kSimd128       | Raw Simd128       | Split into 4 Word32 values and tag   |
// |                |                   | them.                                |
//
// 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.
//
// Finally, it is important that this function does not call `RecordWrite` which
// is why "setup" is in charge of all allocations and we are using
// UNSAFE_SKIP_WRITE_BARRIER. The reason for this is that `RecordWrite` may
// clobber the top 64 bits of Simd128 registers. This is the case on x64, ia32
// and Arm64 for example.
Handle<Code> BuildTeardownFunction(
    Isolate* isolate, CallDescriptor* call_descriptor,
    const std::vector<AllocatedOperand>& parameters) { … }

// Print the content of `value`, representing the register or stack slot
// described by `operand`.
void PrintStateValue(std::ostream& os, Isolate* isolate,
                     DirectHandle<Object> value, AllocatedOperand operand) { … }

bool TestSimd128Moves() { … }

}  // 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.
//
// The following representations are tested:
//   - kTagged
//   - kFloat32
//   - kFloat64
//   - kSimd128 (if supported)
// 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 as well
//     as a newly allocated FixedArray as a second argument which will hold the
//     final results. Thanks to the custom CallDescriptor, registers and stack
//     slots get initialised according to the content of the initial 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 receives the final results as a FixedArray, fills
//     it with the rest of its arguments and returns it. 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
// |                                               |
// | Allocate a new FixedArray `result` with       |
// | initial values.                               |
// |                                               |
// | Call test(teardown, result, state[0],         |
// |           state[1], state[2], ...);           |
// '-----------------------------------------------'
//   |
//   V
// .----------------test-------------------------------.
// | - Move(param3, param42);                          |
// | - Swap(param64, param4);                          |
// | - Move(param2, param6);                           | <- CodeGeneratorTester
// | ...                                               |
// |                                                   |
// | // "teardown" is the first parameter as well as   |
// | // the callee.                                    |
// | TailCall teardown(teardown, result, param2, ...); |
// '---------------------------------------------------'
//   |
//   V
// .----------------teardown---------------------------.
// | Fill in the incoming `result` FixedArray with all |
// | parameters and return it.                         | <- CodeStubAssembler
// '---------------------------------------------------'

class TestEnvironment : public HandleAndZoneScope { … };

// static
constexpr int TestEnvironment::kGeneralRegisterCount;
constexpr int TestEnvironment::kDoubleRegisterCount;
constexpr int TestEnvironment::kTaggedSlotCount;
constexpr int TestEnvironment::kFloat32SlotCount;
constexpr int TestEnvironment::kFloat64SlotCount;
constexpr int TestEnvironment::kSimd128SlotCount;
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`.
class CodeGeneratorTester { … };

// 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
// SimulateSequentialMoves, SimulateParallelMoves and SimulateSwaps.

// Allocate space between slots to increase coverage of moves with larger
// ranges. Note that this affects how much stack is allocated when running the
// generated code. It means we have to be careful not to exceed the stack limit,
// which is lower on Windows.
#ifdef V8_OS_WIN
constexpr int kExtraSpace = 0;
#else
constexpr int kExtraSpace = …;
#endif

TEST(FuzzAssembleMove) { … }

// Test integration with the gap resolver by resolving parallel moves first.
TEST(FuzzAssembleParallelMove) { … }

TEST(FuzzAssembleSwap) { … }

TEST(FuzzAssembleMoveAndSwap) { … }

TEST(AssembleTailCallGap) { … }

#if V8_ENABLE_WEBASSEMBLY
namespace {

std::shared_ptr<wasm::NativeModule> AllocateNativeModule(Isolate* isolate,
                                                         size_t code_size) { … }

}  // namespace

// Test stack argument pushing with some gaps that require stack pointer
// adjustment.
TEST(Regress_1171759) { … }
#endif  // V8_ENABLE_WEBASSEMBLY

}  // namespace compiler
}  // namespace internal
}  // namespace v8
chromium/v8/test/cctest/compiler/test-code-generator.cc
