[PATCH] D141834: [RISCV][NFC] Use uncompressInst to relax instructions

[Wang Pengcheng via Phabricator via llvm-commits]

pcwang-thead created this revision.
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As the TODO said, we can just use generated uncompressInst to
relax instructions.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D141834

Files:
  llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
  llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.h


Index: llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.h
===================================================================
--- llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.h
+++ llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.h
@@ -14,6 +14,7 @@
 #include "MCTargetDesc/RISCVMCTargetDesc.h"
 #include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 
 namespace llvm {
@@ -23,16 +24,17 @@
 
 class RISCVAsmBackend : public MCAsmBackend {
   const MCSubtargetInfo &STI;
+  const MCRegisterInfo &MRI;
   uint8_t OSABI;
   bool Is64Bit;
   bool ForceRelocs = false;
   const MCTargetOptions &TargetOptions;
 
 public:
-  RISCVAsmBackend(const MCSubtargetInfo &STI, uint8_t OSABI, bool Is64Bit,
-                  const MCTargetOptions &Options)
-      : MCAsmBackend(support::little), STI(STI), OSABI(OSABI), Is64Bit(Is64Bit),
-        TargetOptions(Options) {
+  RISCVAsmBackend(const MCSubtargetInfo &STI, const MCRegisterInfo &MRI,
+                  uint8_t OSABI, bool Is64Bit, const MCTargetOptions &Options)
+      : MCAsmBackend(support::little), STI(STI), MRI(MRI), OSABI(OSABI),
+        Is64Bit(Is64Bit), TargetOptions(Options) {
     RISCVFeatures::validate(STI.getTargetTriple(), STI.getFeatureBits());
   }
   ~RISCVAsmBackend() override = default;
Index: llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
===================================================================
--- llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
+++ llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -27,6 +27,10 @@
 
 using namespace llvm;
 
+// Include the auto-generated portion of the compress emitter.
+#define GEN_UNCOMPRESS_INSTR
+#include "RISCVGenCompressInstEmitter.inc"
+
 std::optional<MCFixupKind> RISCVAsmBackend::getFixupKind(StringRef Name) const {
   if (STI.getTargetTriple().isOSBinFormatELF()) {
     unsigned Type;
@@ -167,36 +171,15 @@
 
 void RISCVAsmBackend::relaxInstruction(MCInst &Inst,
                                        const MCSubtargetInfo &STI) const {
-  // TODO: replace this with call to auto generated uncompressinstr() function.
   MCInst Res;
   switch (Inst.getOpcode()) {
   default:
     llvm_unreachable("Opcode not expected!");
   case RISCV::C_BEQZ:
-    // c.beqz $rs1, $imm -> beq $rs1, X0, $imm.
-    Res.setOpcode(RISCV::BEQ);
-    Res.addOperand(Inst.getOperand(0));
-    Res.addOperand(MCOperand::createReg(RISCV::X0));
-    Res.addOperand(Inst.getOperand(1));
-    break;
   case RISCV::C_BNEZ:
-    // c.bnez $rs1, $imm -> bne $rs1, X0, $imm.
-    Res.setOpcode(RISCV::BNE);
-    Res.addOperand(Inst.getOperand(0));
-    Res.addOperand(MCOperand::createReg(RISCV::X0));
-    Res.addOperand(Inst.getOperand(1));
-    break;
   case RISCV::C_J:
-    // c.j $imm -> jal X0, $imm.
-    Res.setOpcode(RISCV::JAL);
-    Res.addOperand(MCOperand::createReg(RISCV::X0));
-    Res.addOperand(Inst.getOperand(0));
-    break;
   case RISCV::C_JAL:
-    // c.jal $imm -> jal X1, $imm.
-    Res.setOpcode(RISCV::JAL);
-    Res.addOperand(MCOperand::createReg(RISCV::X1));
-    Res.addOperand(Inst.getOperand(0));
+    uncompressInst(Res, Inst, MRI, STI);
     break;
   }
   Inst = std::move(Res);
@@ -653,5 +636,5 @@
                                           const MCTargetOptions &Options) {
   const Triple &TT = STI.getTargetTriple();
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
-  return new RISCVAsmBackend(STI, OSABI, TT.isArch64Bit(), Options);
+  return new RISCVAsmBackend(STI, MRI, OSABI, TT.isArch64Bit(), Options);
 }


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