[llvm] [RISCV][llvm-exegesis] Add default Pfm cycle counter. (PR #121866)

via llvm-commits llvm-commits at lists.llvm.org
Mon Jan 6 17:51:53 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-tools-llvm-exegesis

@llvm/pr-subscribers-backend-risc-v

Author: Craig Topper (topperc)

<details>
<summary>Changes</summary>

Also tested with Ubuntu on SiFive's HiFive Premier P550 board. Curiously latency is reporting ~1.5 on basic scalar arithmetic, scalar mul is ~3.5, and div is ~36.5. This 0.5 cycles higher than I expect.

This is stacked on #<!-- -->121862

---
Full diff: https://github.com/llvm/llvm-project/pull/121866.diff


9 Files Affected:

- (modified) llvm/lib/Target/RISCV/CMakeLists.txt (+1) 
- (modified) llvm/lib/Target/RISCV/RISCV.td (+6) 
- (added) llvm/lib/Target/RISCV/RISCVPfmCounters.td (+18) 
- (modified) llvm/tools/llvm-exegesis/lib/RISCV/Target.cpp (+3-2) 
- (modified) llvm/unittests/tools/llvm-exegesis/CMakeLists.txt (+3) 
- (added) llvm/unittests/tools/llvm-exegesis/RISCV/CMakeLists.txt (+21) 
- (added) llvm/unittests/tools/llvm-exegesis/RISCV/SnippetGeneratorTest.cpp (+124) 
- (added) llvm/unittests/tools/llvm-exegesis/RISCV/TargetTest.cpp (+68) 
- (added) llvm/unittests/tools/llvm-exegesis/RISCV/TestBase.h (+44) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/CMakeLists.txt b/llvm/lib/Target/RISCV/CMakeLists.txt
index 44661647a86310..98d3615ebab58d 100644
--- a/llvm/lib/Target/RISCV/CMakeLists.txt
+++ b/llvm/lib/Target/RISCV/CMakeLists.txt
@@ -15,6 +15,7 @@ tablegen(LLVM RISCVGenRegisterBank.inc -gen-register-bank)
 tablegen(LLVM RISCVGenRegisterInfo.inc -gen-register-info)
 tablegen(LLVM RISCVGenSearchableTables.inc -gen-searchable-tables)
 tablegen(LLVM RISCVGenSubtargetInfo.inc -gen-subtarget)
+tablegen(LLVM RISCVGenExegesis.inc -gen-exegesis)
 
 set(LLVM_TARGET_DEFINITIONS RISCVGISel.td)
 tablegen(LLVM RISCVGenGlobalISel.inc -gen-global-isel)
diff --git a/llvm/lib/Target/RISCV/RISCV.td b/llvm/lib/Target/RISCV/RISCV.td
index 963124140cd035..4e0c64a5ca2c6f 100644
--- a/llvm/lib/Target/RISCV/RISCV.td
+++ b/llvm/lib/Target/RISCV/RISCV.td
@@ -63,6 +63,12 @@ include "RISCVSchedXiangShanNanHu.td"
 
 include "RISCVProcessors.td"
 
+//===----------------------------------------------------------------------===//
+// Pfm Counters
+//===----------------------------------------------------------------------===//
+
+include "RISCVPfmCounters.td"
+
 //===----------------------------------------------------------------------===//
 // Define the RISC-V target.
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/RISCV/RISCVPfmCounters.td b/llvm/lib/Target/RISCV/RISCVPfmCounters.td
new file mode 100644
index 00000000000000..013e789a9e9217
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVPfmCounters.td
@@ -0,0 +1,18 @@
+//===---- RISCVPfmCounters.td - RISC-V Hardware Counters ---*- tablegen -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This describes the available hardware counters for RISC-V.
+//
+//===----------------------------------------------------------------------===//
+
+def CpuCyclesPfmCounter : PfmCounter<"CYCLES">;
+
+def DefaultPfmCounters : ProcPfmCounters {
+  let CycleCounter = CpuCyclesPfmCounter;
+}
+def : PfmCountersDefaultBinding<DefaultPfmCounters>;
diff --git a/llvm/tools/llvm-exegesis/lib/RISCV/Target.cpp b/llvm/tools/llvm-exegesis/lib/RISCV/Target.cpp
index 41d361532908ca..5636782bdf7f6f 100644
--- a/llvm/tools/llvm-exegesis/lib/RISCV/Target.cpp
+++ b/llvm/tools/llvm-exegesis/lib/RISCV/Target.cpp
@@ -24,6 +24,8 @@
 namespace llvm {
 namespace exegesis {
 
+#include "RISCVGenExegesis.inc"
+
 namespace {
 
 // Stores constant value to a general-purpose (integer) register.
@@ -132,8 +134,7 @@ class ExegesisRISCVTarget : public ExegesisTarget {
 };
 
 ExegesisRISCVTarget::ExegesisRISCVTarget()
-    : ExegesisTarget(ArrayRef<CpuAndPfmCounters>{},
-                     RISCV_MC::isOpcodeAvailable) {}
+    : ExegesisTarget(RISCVCpuPfmCounters, RISCV_MC::isOpcodeAvailable) {}
 
 bool ExegesisRISCVTarget::matchesArch(Triple::ArchType Arch) const {
   return Arch == Triple::riscv32 || Arch == Triple::riscv64;
diff --git a/llvm/unittests/tools/llvm-exegesis/CMakeLists.txt b/llvm/unittests/tools/llvm-exegesis/CMakeLists.txt
index 3ee3a0dc6b5d04..735f17ab03e612 100644
--- a/llvm/unittests/tools/llvm-exegesis/CMakeLists.txt
+++ b/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})
 
diff --git a/llvm/unittests/tools/llvm-exegesis/RISCV/CMakeLists.txt b/llvm/unittests/tools/llvm-exegesis/RISCV/CMakeLists.txt
new file mode 100644
index 00000000000000..1984819be7738b
--- /dev/null
+++ b/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)
diff --git a/llvm/unittests/tools/llvm-exegesis/RISCV/SnippetGeneratorTest.cpp b/llvm/unittests/tools/llvm-exegesis/RISCV/SnippetGeneratorTest.cpp
new file mode 100644
index 00000000000000..22c25d92dfd3eb
--- /dev/null
+++ b/llvm/unittests/tools/llvm-exegesis/RISCV/SnippetGeneratorTest.cpp
@@ -0,0 +1,124 @@
+//===-- 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();
+  auto Error =
+      Generator.generateCodeTemplates(&Instr, AllRegisters).takeError();
+  EXPECT_TRUE((bool)Error);
+  consumeError(std::move(Error));
+}
+
+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
diff --git a/llvm/unittests/tools/llvm-exegesis/RISCV/TargetTest.cpp b/llvm/unittests/tools/llvm-exegesis/RISCV/TargetTest.cpp
new file mode 100644
index 00000000000000..53aed883b9fa67
--- /dev/null
+++ b/llvm/unittests/tools/llvm-exegesis/RISCV/TargetTest.cpp
@@ -0,0 +1,68 @@
+//===-- 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 "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;
+
+constexpr const char kTriple[] = "riscv64-unknown-linux";
+
+class RISCVTargetTest : public ::testing::Test {
+protected:
+  RISCVTargetTest() : ExegesisTarget_(ExegesisTarget::lookup(Triple(kTriple))) {
+    EXPECT_THAT(ExegesisTarget_, NotNull());
+    std::string error;
+    Target_ = TargetRegistry::lookupTarget(kTriple, error);
+    EXPECT_THAT(Target_, NotNull());
+  }
+  static void SetUpTestCase() {
+    LLVMInitializeRISCVTargetInfo();
+    LLVMInitializeRISCVTarget();
+    LLVMInitializeRISCVTargetMC();
+    InitializeRISCVExegesisTarget();
+  }
+
+  const Target *Target_;
+  const ExegesisTarget *const ExegesisTarget_;
+};
+
+TEST_F(RISCVTargetTest, SetRegToConstant) {
+  const std::unique_ptr<MCSubtargetInfo> STI(
+      Target_->createMCSubtargetInfo(kTriple, "generic", ""));
+  const auto Insts = ExegesisTarget_->setRegTo(*STI, RISCV::X10, APInt());
+  EXPECT_THAT(Insts, Not(IsEmpty()));
+}
+
+TEST_F(RISCVTargetTest, DefaultPfmCounters) {
+  const std::string Expected = "CYCLES";
+  EXPECT_EQ(ExegesisTarget_->getPfmCounters("").CycleCounter, Expected);
+  EXPECT_EQ(ExegesisTarget_->getPfmCounters("unknown_cpu").CycleCounter,
+            Expected);
+}
+
+} // namespace
+} // namespace exegesis
+} // namespace llvm
diff --git a/llvm/unittests/tools/llvm-exegesis/RISCV/TestBase.h b/llvm/unittests/tools/llvm-exegesis/RISCV/TestBase.h
new file mode 100644
index 00000000000000..66748fb9a2ce1b
--- /dev/null
+++ b/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

``````````

</details>


https://github.com/llvm/llvm-project/pull/121866


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