llvm-project/llvm/unittests/tools/llvm-exegesis/X86/SnippetGeneratorTest.cpp

313 lines
11 KiB
C++

//===-- SnippetGeneratorTest.cpp --------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "../Common/AssemblerUtils.h"
#include "Latency.h"
#include "LlvmState.h"
#include "MCInstrDescView.h"
#include "RegisterAliasing.h"
#include "Uops.h"
#include "X86InstrInfo.h"
#include <unordered_set>
namespace exegesis {
void InitializeX86ExegesisTarget();
namespace {
using testing::AnyOf;
using testing::ElementsAre;
using testing::HasSubstr;
using testing::Not;
using testing::SizeIs;
using testing::UnorderedElementsAre;
MATCHER(IsInvalid, "") { return !arg.isValid(); }
MATCHER(IsReg, "") { return arg.isReg(); }
class X86SnippetGeneratorTest : public ::testing::Test {
protected:
X86SnippetGeneratorTest()
: State("x86_64-unknown-linux", "haswell"),
MCInstrInfo(State.getInstrInfo()), MCRegisterInfo(State.getRegInfo()) {}
static void SetUpTestCase() {
LLVMInitializeX86TargetInfo();
LLVMInitializeX86TargetMC();
LLVMInitializeX86Target();
LLVMInitializeX86AsmPrinter();
InitializeX86ExegesisTarget();
}
const LLVMState State;
const llvm::MCInstrInfo &MCInstrInfo;
const llvm::MCRegisterInfo &MCRegisterInfo;
};
template <typename BenchmarkRunner>
class SnippetGeneratorTest : public X86SnippetGeneratorTest {
protected:
SnippetGeneratorTest() : Runner(State) {}
CodeTemplate checkAndGetCodeTemplate(unsigned Opcode) {
randomGenerator().seed(0); // Initialize seed.
auto CodeTemplateOrError = Runner.generateCodeTemplate(Opcode);
EXPECT_FALSE(CodeTemplateOrError.takeError()); // Valid configuration.
return std::move(CodeTemplateOrError.get());
}
BenchmarkRunner Runner;
};
using LatencyBenchmarkRunnerTest = SnippetGeneratorTest<LatencyBenchmarkRunner>;
using UopsBenchmarkRunnerTest = SnippetGeneratorTest<UopsBenchmarkRunner>;
TEST_F(LatencyBenchmarkRunnerTest, ImplicitSelfDependency) {
// ADC16i16 self alias because of implicit use and def.
// explicit use 0 : imm
// implicit def : AX
// implicit def : EFLAGS
// implicit use : AX
// implicit use : EFLAGS
const unsigned Opcode = llvm::X86::ADC16i16;
EXPECT_THAT(MCInstrInfo.get(Opcode).getImplicitDefs()[0], llvm::X86::AX);
EXPECT_THAT(MCInstrInfo.get(Opcode).getImplicitDefs()[1], llvm::X86::EFLAGS);
EXPECT_THAT(MCInstrInfo.get(Opcode).getImplicitUses()[0], llvm::X86::AX);
EXPECT_THAT(MCInstrInfo.get(Opcode).getImplicitUses()[1], llvm::X86::EFLAGS);
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("implicit"));
ASSERT_THAT(CT.Instructions, SizeIs(1));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(1)); // Imm.
EXPECT_THAT(IB.VariableValues[0], IsInvalid()) << "Immediate is not set";
}
TEST_F(LatencyBenchmarkRunnerTest, ExplicitSelfDependency) {
// ADD16ri self alias because Op0 and Op1 are tied together.
// explicit def 0 : reg RegClass=GR16
// explicit use 1 : reg RegClass=GR16 | TIED_TO:0
// explicit use 2 : imm
// implicit def : EFLAGS
const unsigned Opcode = llvm::X86::ADD16ri;
EXPECT_THAT(MCInstrInfo.get(Opcode).getImplicitDefs()[0], llvm::X86::EFLAGS);
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("explicit"));
ASSERT_THAT(CT.Instructions, SizeIs(1));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(2));
EXPECT_THAT(IB.VariableValues[0], IsReg()) << "Operand 0 and 1";
EXPECT_THAT(IB.VariableValues[1], IsInvalid()) << "Operand 2 is not set";
}
TEST_F(LatencyBenchmarkRunnerTest, DependencyThroughOtherOpcode) {
// CMP64rr
// explicit use 0 : reg RegClass=GR64
// explicit use 1 : reg RegClass=GR64
// implicit def : EFLAGS
const unsigned Opcode = llvm::X86::CMP64rr;
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("cycle through"));
ASSERT_THAT(CT.Instructions, SizeIs(2));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(2));
EXPECT_THAT(IB.VariableValues, AnyOf(ElementsAre(IsReg(), IsInvalid()),
ElementsAre(IsInvalid(), IsReg())));
EXPECT_THAT(CT.Instructions[1].getOpcode(), Not(Opcode));
// TODO: check that the two instructions alias each other.
}
TEST_F(LatencyBenchmarkRunnerTest, LAHF) {
const unsigned Opcode = llvm::X86::LAHF;
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("cycle through"));
ASSERT_THAT(CT.Instructions, SizeIs(2));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(0));
}
TEST_F(UopsBenchmarkRunnerTest, ParallelInstruction) {
// BNDCL32rr is parallel no matter what.
// explicit use 0 : reg RegClass=BNDR
// explicit use 1 : reg RegClass=GR32
const unsigned Opcode = llvm::X86::BNDCL32rr;
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("parallel"));
ASSERT_THAT(CT.Instructions, SizeIs(1));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(2));
EXPECT_THAT(IB.VariableValues[0], IsInvalid());
EXPECT_THAT(IB.VariableValues[1], IsInvalid());
}
TEST_F(UopsBenchmarkRunnerTest, SerialInstruction) {
// CDQ is serial no matter what.
// implicit def : EAX
// implicit def : EDX
// implicit use : EAX
const unsigned Opcode = llvm::X86::CDQ;
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("serial"));
ASSERT_THAT(CT.Instructions, SizeIs(1));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(0));
}
TEST_F(UopsBenchmarkRunnerTest, StaticRenaming) {
// CMOVA32rr has tied variables, we enumarate the possible values to execute
// as many in parallel as possible.
// explicit def 0 : reg RegClass=GR32
// explicit use 1 : reg RegClass=GR32 | TIED_TO:0
// explicit use 2 : reg RegClass=GR32
// implicit use : EFLAGS
const unsigned Opcode = llvm::X86::CMOVA32rr;
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("static renaming"));
constexpr const unsigned kInstructionCount = 15;
ASSERT_THAT(CT.Instructions, SizeIs(kInstructionCount));
std::unordered_set<unsigned> AllDefRegisters;
for (const auto &IB : CT.Instructions) {
ASSERT_THAT(IB.VariableValues, SizeIs(2));
AllDefRegisters.insert(IB.VariableValues[0].getReg());
}
EXPECT_THAT(AllDefRegisters, SizeIs(kInstructionCount))
<< "Each instruction writes to a different register";
}
TEST_F(UopsBenchmarkRunnerTest, NoTiedVariables) {
// CMOV_GR32 has no tied variables, we make sure def and use are different
// from each other.
// explicit def 0 : reg RegClass=GR32
// explicit use 1 : reg RegClass=GR32
// explicit use 2 : reg RegClass=GR32
// explicit use 3 : imm
// implicit use : EFLAGS
const unsigned Opcode = llvm::X86::CMOV_GR32;
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("no tied variables"));
ASSERT_THAT(CT.Instructions, SizeIs(1));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(4));
EXPECT_THAT(IB.VariableValues[0].getReg(), Not(IB.VariableValues[1].getReg()))
<< "Def is different from first Use";
EXPECT_THAT(IB.VariableValues[0].getReg(), Not(IB.VariableValues[2].getReg()))
<< "Def is different from second Use";
EXPECT_THAT(IB.VariableValues[3], IsInvalid());
}
TEST_F(UopsBenchmarkRunnerTest, MemoryUse) {
// Mov32rm reads from memory.
const unsigned Opcode = llvm::X86::MOV32rm;
const CodeTemplate CT = checkAndGetCodeTemplate(Opcode);
EXPECT_THAT(CT.Info, HasSubstr("no tied variables"));
ASSERT_THAT(CT.Instructions,
SizeIs(UopsBenchmarkRunner::kMinNumDifferentAddresses));
const InstructionBuilder &IB = CT.Instructions[0];
EXPECT_THAT(IB.getOpcode(), Opcode);
ASSERT_THAT(IB.VariableValues, SizeIs(6));
EXPECT_EQ(IB.VariableValues[2].getImm(), 1);
EXPECT_EQ(IB.VariableValues[3].getReg(), 0u);
EXPECT_EQ(IB.VariableValues[4].getImm(), 0);
EXPECT_EQ(IB.VariableValues[5].getReg(), 0u);
}
TEST_F(UopsBenchmarkRunnerTest, MemoryUse_Movsb) {
// MOVSB writes to scratch memory register.
const unsigned Opcode = llvm::X86::MOVSB;
auto Error = Runner.generateCodeTemplate(Opcode).takeError();
EXPECT_TRUE((bool)Error);
llvm::consumeError(std::move(Error));
}
class FakeBenchmarkRunner : public BenchmarkRunner {
public:
FakeBenchmarkRunner(const LLVMState &State)
: BenchmarkRunner(State, InstructionBenchmark::Unknown) {}
Instruction createInstruction(unsigned Opcode) {
return Instruction(State.getInstrInfo().get(Opcode), RATC);
}
private:
llvm::Expected<CodeTemplate>
generateCodeTemplate(unsigned Opcode) const override {
return llvm::make_error<llvm::StringError>("not implemented",
llvm::inconvertibleErrorCode());
}
std::vector<BenchmarkMeasure>
runMeasurements(const ExecutableFunction &EF, ScratchSpace &Scratch,
const unsigned NumRepetitions) const override {
return {};
}
};
using FakeSnippetGeneratorTest = SnippetGeneratorTest<FakeBenchmarkRunner>;
TEST_F(FakeSnippetGeneratorTest, ComputeRegsToDefAdd16ri) {
// ADD16ri:
// explicit def 0 : reg RegClass=GR16
// explicit use 1 : reg RegClass=GR16 | TIED_TO:0
// explicit use 2 : imm
// implicit def : EFLAGS
InstructionBuilder IB(Runner.createInstruction(llvm::X86::ADD16ri));
IB.getValueFor(IB.Instr.Variables[0]) =
llvm::MCOperand::createReg(llvm::X86::AX);
std::vector<InstructionBuilder> Snippet;
Snippet.push_back(std::move(IB));
const auto RegsToDef = Runner.computeRegsToDef(Snippet);
EXPECT_THAT(RegsToDef, UnorderedElementsAre(llvm::X86::AX));
}
TEST_F(FakeSnippetGeneratorTest, ComputeRegsToDefAdd64rr) {
// ADD64rr:
// mov64ri rax, 42
// add64rr rax, rax, rbx
// -> only rbx needs defining.
std::vector<InstructionBuilder> Snippet;
{
InstructionBuilder Mov(Runner.createInstruction(llvm::X86::MOV64ri));
Mov.getValueFor(Mov.Instr.Variables[0]) =
llvm::MCOperand::createReg(llvm::X86::RAX);
Mov.getValueFor(Mov.Instr.Variables[1]) = llvm::MCOperand::createImm(42);
Snippet.push_back(std::move(Mov));
}
{
InstructionBuilder Add(Runner.createInstruction(llvm::X86::ADD64rr));
Add.getValueFor(Add.Instr.Variables[0]) =
llvm::MCOperand::createReg(llvm::X86::RAX);
Add.getValueFor(Add.Instr.Variables[1]) =
llvm::MCOperand::createReg(llvm::X86::RBX);
Snippet.push_back(std::move(Add));
}
const auto RegsToDef = Runner.computeRegsToDef(Snippet);
EXPECT_THAT(RegsToDef, UnorderedElementsAre(llvm::X86::RBX));
}
} // namespace
} // namespace exegesis