[LoongArch][MC] Refine MCInstrAnalysis based on registers used

[zhaoqi5]

MCInstrAnalysis can return properties of instructions (e.g., isCall(), isBranch(),...) based on the informations that MCInstrDesc can get from InstrInfo.td files. These infos are based on opcodes only, but JIRL can have different properties based on different registers used.

So this patch refines several MCInstrAnalysis methods: isTerminator, isCall,isReturn,isBranch,isUnconditionalBranch and isIndirectBranch.

This patch also allows BOLT which will be supported on LoongArch later to get right instruction infos.

[llvmbot]

@llvm/pr-subscribers-backend-loongarch

Author: None (zhaoqi5)

Changes

MCInstrAnalysis can return properties of instructions (e.g., isCall(), isBranch(),...) based on the informations that MCInstrDesc can get from InstrInfo.td files. These infos are based on opcodes only, but JIRL can have different properties based on different registers used.

So this patch refines several MCInstrAnalysis methods: isTerminator, isCall,isReturn,isBranch,isUnconditionalBranch and isIndirectBranch.

This patch also allows BOLT which will be supported on LoongArch later to get right instruction infos.

---

Full diff: https://github.com/llvm/llvm-project/pull/71276.diff

3 Files Affected:

• (modified) llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchMCTargetDesc.cpp (+76)
• (modified) llvm/unittests/Target/LoongArch/CMakeLists.txt (+1)
• (added) llvm/unittests/Target/LoongArch/MCInstrAnalysisTest.cpp (+107)

diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchMCTargetDesc.cpp b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchMCTargetDesc.cpp
index 942e667bc261872..d580c3457fecff8 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchMCTargetDesc.cpp
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchMCTargetDesc.cpp
@@ -104,6 +104,82 @@ class LoongArchMCInstrAnalysis : public MCInstrAnalysis {
 
     return false;
   }
+
+  bool isTerminator(const MCInst &Inst) const override {
+    if (MCInstrAnalysis::isTerminator(Inst))
+      return true;
+
+    switch (Inst.getOpcode()) {
+    default:
+      return false;
+    case LoongArch::JIRL:
+      return Inst.getOperand(0).getReg() == LoongArch::R0;
+    }
+  }
+
+  bool isCall(const MCInst &Inst) const override {
+    if (MCInstrAnalysis::isCall(Inst))
+      return true;
+
+    switch (Inst.getOpcode()) {
+    default:
+      return false;
+    case LoongArch::JIRL:
+      return Inst.getOperand(0).getReg() != LoongArch::R0;
+    }
+  }
+
+  bool isReturn(const MCInst &Inst) const override {
+    if (MCInstrAnalysis::isReturn(Inst))
+      return true;
+
+    switch (Inst.getOpcode()) {
+    default:
+      return false;
+    case LoongArch::JIRL:
+      return Inst.getOperand(0).getReg() == LoongArch::R0 &&
+             Inst.getOperand(1).getReg() == LoongArch::R1;
+    }
+  }
+
+  bool isBranch(const MCInst &Inst) const override {
+    if (MCInstrAnalysis::isBranch(Inst))
+      return true;
+
+    switch (Inst.getOpcode()) {
+    default:
+      return false;
+    case LoongArch::JIRL:
+      return Inst.getOperand(0).getReg() == LoongArch::R0 &&
+             Inst.getOperand(1).getReg() != LoongArch::R1;
+    }
+  }
+
+  bool isUnconditionalBranch(const MCInst &Inst) const override {
+    if (MCInstrAnalysis::isUnconditionalBranch(Inst))
+      return true;
+
+    switch (Inst.getOpcode()) {
+    default:
+      return false;
+    case LoongArch::JIRL:
+      return Inst.getOperand(0).getReg() == LoongArch::R0 &&
+             Inst.getOperand(1).getReg() != LoongArch::R1;
+    }
+  }
+
+  bool isIndirectBranch(const MCInst &Inst) const override {
+    if (MCInstrAnalysis::isIndirectBranch(Inst))
+      return true;
+
+    switch (Inst.getOpcode()) {
+    default:
+      return false;
+    case LoongArch::JIRL:
+      return Inst.getOperand(0).getReg() == LoongArch::R0 &&
+             Inst.getOperand(1).getReg() != LoongArch::R1;
+    }
+  }
 };
 
 } // end namespace
diff --git a/llvm/unittests/Target/LoongArch/CMakeLists.txt b/llvm/unittests/Target/LoongArch/CMakeLists.txt
index fef4f8e15461834..e6f8ec073721f6e 100644
--- a/llvm/unittests/Target/LoongArch/CMakeLists.txt
+++ b/llvm/unittests/Target/LoongArch/CMakeLists.txt
@@ -20,6 +20,7 @@ set(LLVM_LINK_COMPONENTS
 
 add_llvm_target_unittest(LoongArchTests
   InstSizes.cpp
+  MCInstrAnalysisTest.cpp
   )
 
 set_property(TARGET LoongArchTests PROPERTY FOLDER "Tests/UnitTests/TargetTests")
diff --git a/llvm/unittests/Target/LoongArch/MCInstrAnalysisTest.cpp b/llvm/unittests/Target/LoongArch/MCInstrAnalysisTest.cpp
new file mode 100644
index 000000000000000..6a208d274a0d39e
--- /dev/null
+++ b/llvm/unittests/Target/LoongArch/MCInstrAnalysisTest.cpp
@@ -0,0 +1,107 @@
+//===- MCInstrAnalysisTest.cpp - LoongArchMCInstrAnalysis unit tests ------===//
+//
+// 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 "llvm/MC/MCInstrAnalysis.h"
+#include "MCTargetDesc/LoongArchMCTargetDesc.h"
+#include "llvm/MC/MCInstBuilder.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+
+#include "gtest/gtest.h"
+
+#include <memory>
+
+using namespace llvm;
+
+namespace {
+
+class InstrAnalysisTest : public testing::TestWithParam<const char *> {
+protected:
+  std::unique_ptr<const MCInstrInfo> Info;
+  std::unique_ptr<const MCInstrAnalysis> Analysis;
+
+  static void SetUpTestSuite() {
+    LLVMInitializeLoongArchTargetInfo();
+    LLVMInitializeLoongArchTarget();
+    LLVMInitializeLoongArchTargetMC();
+  }
+
+  InstrAnalysisTest() {
+    std::string Error;
+    const Target *TheTarget =
+        TargetRegistry::lookupTarget(Triple::normalize(GetParam()), Error);
+    Info = std::unique_ptr<const MCInstrInfo>(TheTarget->createMCInstrInfo());
+    Analysis = std::unique_ptr<const MCInstrAnalysis>(
+        TheTarget->createMCInstrAnalysis(Info.get()));
+  }
+};
+
+} // namespace
+
+static MCInst beq() {
+  return MCInstBuilder(LoongArch::BEQ)
+      .addReg(LoongArch::R0)
+      .addReg(LoongArch::R1)
+      .addImm(32);
+}
+
+static MCInst bl() { return MCInstBuilder(LoongArch::BL).addImm(32); }
+
+static MCInst jirl(unsigned RD, unsigned RJ = LoongArch::R10) {
+  return MCInstBuilder(LoongArch::JIRL).addReg(RD).addReg(RJ).addImm(16);
+}
+
+TEST_P(InstrAnalysisTest, IsTerminator) {
+  EXPECT_TRUE(Analysis->isTerminator(beq()));
+  EXPECT_FALSE(Analysis->isTerminator(bl()));
+  EXPECT_TRUE(Analysis->isTerminator(jirl(LoongArch::R0)));
+  EXPECT_FALSE(Analysis->isTerminator(jirl(LoongArch::R5)));
+}
+
+TEST_P(InstrAnalysisTest, IsCall) {
+  EXPECT_FALSE(Analysis->isCall(beq()));
+  EXPECT_TRUE(Analysis->isCall(bl()));
+  EXPECT_TRUE(Analysis->isCall(jirl(LoongArch::R1)));
+  EXPECT_FALSE(Analysis->isCall(jirl(LoongArch::R0)));
+}
+
+TEST_P(InstrAnalysisTest, IsReturn) {
+  EXPECT_FALSE(Analysis->isReturn(beq()));
+  EXPECT_FALSE(Analysis->isReturn(bl()));
+  EXPECT_TRUE(Analysis->isReturn(jirl(LoongArch::R0, LoongArch::R1)));
+  EXPECT_FALSE(Analysis->isReturn(jirl(LoongArch::R0)));
+  EXPECT_FALSE(Analysis->isReturn(jirl(LoongArch::R1)));
+}
+
+TEST_P(InstrAnalysisTest, IsBranch) {
+  EXPECT_TRUE(Analysis->isBranch(beq()));
+  EXPECT_FALSE(Analysis->isBranch(bl()));
+  EXPECT_TRUE(Analysis->isBranch(jirl(LoongArch::R0)));
+  EXPECT_FALSE(Analysis->isBranch(jirl(LoongArch::R1)));
+  EXPECT_FALSE(Analysis->isBranch(jirl(LoongArch::R0, LoongArch::R1)));
+}
+
+TEST_P(InstrAnalysisTest, IsUnconditionalBranch) {
+  EXPECT_FALSE(Analysis->isUnconditionalBranch(beq()));
+  EXPECT_FALSE(Analysis->isUnconditionalBranch(bl()));
+  EXPECT_TRUE(Analysis->isUnconditionalBranch(jirl(LoongArch::R0)));
+  EXPECT_FALSE(Analysis->isUnconditionalBranch(jirl(LoongArch::R1)));
+  EXPECT_FALSE(
+      Analysis->isUnconditionalBranch(jirl(LoongArch::R0, LoongArch::R1)));
+}
+
+TEST_P(InstrAnalysisTest, IsIndirectBranch) {
+  EXPECT_FALSE(Analysis->isIndirectBranch(beq()));
+  EXPECT_FALSE(Analysis->isIndirectBranch(bl()));
+  EXPECT_TRUE(Analysis->isIndirectBranch(jirl(LoongArch::R0)));
+  EXPECT_FALSE(Analysis->isIndirectBranch(jirl(LoongArch::R1)));
+  EXPECT_FALSE(Analysis->isIndirectBranch(jirl(LoongArch::R0, LoongArch::R1)));
+}
+
+INSTANTIATE_TEST_SUITE_P(LA32And64, InstrAnalysisTest,
+                         testing::Values("loongarch32", "loongarch64"));

[SixWeining]

LGTM.