[RISCV][llvm-exegesis] Add unittests. NFC (llvm#121862)

This is largely based on Mips and PowerPC.

llvm/unittests/tools/llvm-exegesis/CMakeLists.txt

@@ -53,6 +53,9 @@ endif()
 if(LLVM_TARGETS_TO_BUILD MATCHES "Mips")
   include(Mips/CMakeLists.txt)
 endif()
+if(LLVM_TARGETS_TO_BUILD MATCHES "RISCV")
+  include(RISCV/CMakeLists.txt)
+endif()
 
 include_directories(${exegesis_includes})
 

llvm/unittests/tools/llvm-exegesis/RISCV/CMakeLists.txt

@@ -0,0 +1,21 @@
+add_llvm_exegesis_unittest_includes(
+  ${LLVM_MAIN_SRC_DIR}/lib/Target/RISCV
+  ${LLVM_BINARY_DIR}/lib/Target/RISCV
+  ${LLVM_MAIN_SRC_DIR}/tools/llvm-exegesis/lib
+  )
+
+add_llvm_exegesis_unittest_link_components(
+  MC
+  MCParser
+  Object
+  Support
+  Symbolize
+  RISCV
+  )
+
+add_llvm_exegesis_unittest_sources(
+  SnippetGeneratorTest.cpp
+  TargetTest.cpp
+  )
+add_llvm_exegesis_unittest_link_libraries(
+  LLVMExegesisRISCV)

llvm/unittests/tools/llvm-exegesis/RISCV/SnippetGeneratorTest.cpp

@@ -0,0 +1,122 @@
+//===-- SnippetGeneratorTest.cpp --------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "../Common/AssemblerUtils.h"
+#include "LlvmState.h"
+#include "MCInstrDescView.h"
+#include "ParallelSnippetGenerator.h"
+#include "RISCVInstrInfo.h"
+#include "RegisterAliasing.h"
+#include "SerialSnippetGenerator.h"
+#include "TestBase.h"
+
+namespace llvm {
+namespace exegesis {
+namespace {
+
+using testing::AnyOf;
+using testing::ElementsAre;
+using testing::HasSubstr;
+using testing::SizeIs;
+
+MATCHER(IsInvalid, "") { return !arg.isValid(); }
+MATCHER(IsReg, "") { return arg.isReg(); }
+
+template <typename SnippetGeneratorT>
+class RISCVSnippetGeneratorTest : public RISCVTestBase {
+protected:
+  RISCVSnippetGeneratorTest() : Generator(State, SnippetGenerator::Options()) {}
+
+  std::vector<CodeTemplate> checkAndGetCodeTemplates(unsigned Opcode) {
+    randomGenerator().seed(0); // Initialize seed.
+    const Instruction &Instr = State.getIC().getInstr(Opcode);
+    auto CodeTemplateOrError = Generator.generateCodeTemplates(
+        &Instr, State.getRATC().emptyRegisters());
+    EXPECT_FALSE(CodeTemplateOrError.takeError()); // Valid configuration.
+    return std::move(CodeTemplateOrError.get());
+  }
+
+  SnippetGeneratorT Generator;
+};
+
+using RISCVSerialSnippetGeneratorTest =
+    RISCVSnippetGeneratorTest<SerialSnippetGenerator>;
+
+using RISCVParallelSnippetGeneratorTest =
+    RISCVSnippetGeneratorTest<ParallelSnippetGenerator>;
+
+TEST_F(RISCVSerialSnippetGeneratorTest,
+       ImplicitSelfDependencyThroughExplicitRegs) {
+  // - ADD
+  // - Op0 Explicit Def RegClass(GPR)
+  // - Op1 Explicit Use RegClass(GPR)
+  // - Op2 Explicit Use RegClass(GPR)
+  // - Var0 [Op0]
+  // - Var1 [Op1]
+  // - Var2 [Op2]
+  // - hasAliasingRegisters
+  const unsigned Opcode = RISCV::ADD;
+  const auto CodeTemplates = checkAndGetCodeTemplates(Opcode);
+  ASSERT_THAT(CodeTemplates, SizeIs(1));
+  const auto &CT = CodeTemplates[0];
+  EXPECT_THAT(CT.Execution, ExecutionMode::SERIAL_VIA_EXPLICIT_REGS);
+  ASSERT_THAT(CT.Instructions, SizeIs(1));
+  const InstructionTemplate &IT = CT.Instructions[0];
+  EXPECT_THAT(IT.getOpcode(), Opcode);
+  ASSERT_THAT(IT.getVariableValues(), SizeIs(3));
+  EXPECT_THAT(IT.getVariableValues(),
+              AnyOf(ElementsAre(IsReg(), IsInvalid(), IsReg()),
+                    ElementsAre(IsReg(), IsReg(), IsInvalid())))
+      << "Op0 is either set to Op1 or to Op2";
+}
+
+TEST_F(RISCVSerialSnippetGeneratorTest,
+       ImplicitSelfDependencyThroughExplicitRegsForbidAll) {
+  // - XOR
+  // - Op0 Explicit Def RegClass(GPR)
+  // - Op1 Explicit Use RegClass(GPR)
+  // - Op2 Explicit Use RegClass(GPR)
+  // - Var0 [Op0]
+  // - Var1 [Op1]
+  // - Var2 [Op2]
+  // - hasAliasingRegisters
+  randomGenerator().seed(0); // Initialize seed.
+  const Instruction &Instr = State.getIC().getInstr(RISCV::XOR);
+  auto AllRegisters = State.getRATC().emptyRegisters();
+  AllRegisters.flip();
+  EXPECT_TRUE(errorToBool(
+      Generator.generateCodeTemplates(&Instr, AllRegisters).takeError()));
+}
+
+TEST_F(RISCVParallelSnippetGeneratorTest, MemoryUse) {
+  // LB reads from memory.
+  // - LB
+  // - Op0 Explicit Def RegClass(GPR)
+  // - Op1 Explicit Use Memory RegClass(GPR)
+  // - Op2 Explicit Use Memory
+  // - Var0 [Op0]
+  // - Var1 [Op1]
+  // - Var2 [Op2]
+  // - hasMemoryOperands
+  const unsigned Opcode = RISCV::LB;
+  const auto CodeTemplates = checkAndGetCodeTemplates(Opcode);
+  ASSERT_THAT(CodeTemplates, SizeIs(1));
+  const auto &CT = CodeTemplates[0];
+  EXPECT_THAT(CT.Info, HasSubstr("instruction has no tied variables"));
+  EXPECT_THAT(CT.Execution, ExecutionMode::UNKNOWN);
+  ASSERT_THAT(CT.Instructions,
+              SizeIs(ParallelSnippetGenerator::kMinNumDifferentAddresses));
+  const InstructionTemplate &IT = CT.Instructions[0];
+  EXPECT_THAT(IT.getOpcode(), Opcode);
+  ASSERT_THAT(IT.getVariableValues(), SizeIs(3));
+  EXPECT_EQ(IT.getVariableValues()[1].getReg(), RISCV::X10);
+}
+
+} // namespace
+} // namespace exegesis
+} // namespace llvm

llvm/unittests/tools/llvm-exegesis/RISCV/TargetTest.cpp

@@ -0,0 +1,47 @@
+//===-- TargetTest.cpp ---------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Target.h"
+
+#include <cassert>
+#include <memory>
+
+#include "MCTargetDesc/RISCVMCTargetDesc.h"
+#include "TestBase.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+namespace exegesis {
+
+void InitializeRISCVExegesisTarget();
+
+namespace {
+
+using testing::IsEmpty;
+using testing::Not;
+using testing::NotNull;
+
+class RISCVTargetTest : public RISCVTestBase {
+protected:
+  std::vector<MCInst> setRegTo(unsigned Reg, const APInt &Value) {
+    return State.getExegesisTarget().setRegTo(State.getSubtargetInfo(), Reg,
+                                              Value);
+  }
+};
+
+TEST_F(RISCVTargetTest, SetRegToConstant) {
+  const auto Insts = setRegTo(RISCV::X10, APInt());
+  EXPECT_THAT(Insts, Not(IsEmpty()));
+}
+
+} // namespace
+} // namespace exegesis
+} // namespace llvm

llvm/unittests/tools/llvm-exegesis/RISCV/TestBase.h

@@ -0,0 +1,44 @@
+//===-- TestBase.h ----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// Test fixture common to all RISC-V tests.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_UNITTESTS_TOOLS_LLVMEXEGESIS_RISCV_TESTBASE_H
+#define LLVM_UNITTESTS_TOOLS_LLVMEXEGESIS_RISCV_TESTBASE_H
+
+#include "LlvmState.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+namespace exegesis {
+
+void InitializeRISCVExegesisTarget();
+
+class RISCVTestBase : public ::testing::Test {
+protected:
+  RISCVTestBase()
+      : State(cantFail(
+            LLVMState::Create("riscv64-unknown-linux", "generic-rv64"))) {}
+
+  static void SetUpTestCase() {
+    LLVMInitializeRISCVTargetInfo();
+    LLVMInitializeRISCVTargetMC();
+    LLVMInitializeRISCVTarget();
+    InitializeRISCVExegesisTarget();
+  }
+
+  const LLVMState State;
+};
+
+} // namespace exegesis
+} // namespace llvm
+
+#endif