4 files changed, 38 insertions, 11 deletions
diff --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index f79cbd7fb6b..b4d206db54c 100644
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -1219,6 +1219,10 @@ OperandMatchResultTy RISCVAsmParser::parseCallSymbol(OperandVector &Operands) {
   if (getLexer().getKind() != AsmToken::Identifier)
     return MatchOperand_NoMatch;
 
+  // Avoid parsing the register in `call rd, foo` as a call symbol.
+  if (getLexer().peekTok().getKind() != AsmToken::EndOfStatement)
+    return MatchOperand_NoMatch;
+
   StringRef Identifier;
   if (getParser().parseIdentifier(Identifier))
     return MatchOperand_ParseFail;
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp
index 32e9f4e3a6c..0fc775f63ed 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp
@@ -88,19 +88,29 @@ MCCodeEmitter *llvm::createRISCVMCCodeEmitter(const MCInstrInfo &MCII,
   return new RISCVMCCodeEmitter(Ctx, MCII);
 }
 
-// Expand PseudoCALL and PseudoTAIL to AUIPC and JALR with relocation types.
-// We expand PseudoCALL and PseudoTAIL while encoding, meaning AUIPC and JALR
-// won't go through RISCV MC to MC compressed instruction transformation. This
-// is acceptable because AUIPC has no 16-bit form and C_JALR have no immediate
-// operand field.  We let linker relaxation deal with it. When linker
-// relaxation enabled, AUIPC and JALR have chance relax to JAL. If C extension
-// is enabled, JAL has chance relax to C_JAL.
+// Expand PseudoCALL(Reg) and PseudoTAIL to AUIPC and JALR with relocation
+// types. We expand PseudoCALL(Reg) and PseudoTAIL while encoding, meaning AUIPC
+// and JALR won't go through RISCV MC to MC compressed instruction
+// transformation. This is acceptable because AUIPC has no 16-bit form and
+// C_JALR have no immediate operand field.  We let linker relaxation deal with
+// it. When linker relaxation enabled, AUIPC and JALR have chance relax to JAL.
+// If C extension is enabled, JAL has chance relax to C_JAL.
 void RISCVMCCodeEmitter::expandFunctionCall(const MCInst &MI, raw_ostream &OS,
                                             SmallVectorImpl<MCFixup> &Fixups,
                                             const MCSubtargetInfo &STI) const {
   MCInst TmpInst;
-  MCOperand Func = MI.getOperand(0);
-  unsigned Ra = (MI.getOpcode() == RISCV::PseudoTAIL) ? RISCV::X6 : RISCV::X1;
+  MCOperand Func;
+  unsigned Ra;
+  if (MI.getOpcode() == RISCV::PseudoTAIL) {
+    Func = MI.getOperand(0);
+    Ra = RISCV::X6;
+  } else if (MI.getOpcode() == RISCV::PseudoCALLReg) {
+    Func = MI.getOperand(1);
+    Ra = MI.getOperand(0).getReg();
+  } else {
+    Func = MI.getOperand(0);
+    Ra = RISCV::X1;
+  }
   uint32_t Binary;
 
   assert(Func.isExpr() && "Expected expression");
@@ -118,7 +128,7 @@ void RISCVMCCodeEmitter::expandFunctionCall(const MCInst &MI, raw_ostream &OS,
     // Emit JALR X0, X6, 0
     TmpInst = MCInstBuilder(RISCV::JALR).addReg(RISCV::X0).addReg(Ra).addImm(0);
   else
-    // Emit JALR X1, X1, 0
+    // Emit JALR Ra, Ra, 0
     TmpInst = MCInstBuilder(RISCV::JALR).addReg(Ra).addReg(Ra).addImm(0);
   Binary = getBinaryCodeForInstr(TmpInst, Fixups, STI);
   support::endian::write(OS, Binary, support::little);
@@ -169,7 +179,8 @@ void RISCVMCCodeEmitter::encodeInstruction(const MCInst &MI, raw_ostream &OS,
   // Get byte count of instruction.
   unsigned Size = Desc.getSize();
 
-  if (MI.getOpcode() == RISCV::PseudoCALL ||
+  if (MI.getOpcode() == RISCV::PseudoCALLReg ||
+      MI.getOpcode() == RISCV::PseudoCALL ||
       MI.getOpcode() == RISCV::PseudoTAIL) {
     expandFunctionCall(MI, OS, Fixups, STI);
     MCNumEmitted += 2;
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
index 9d1361b4df7..2608906bb43 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -436,6 +436,7 @@ unsigned RISCVInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
   case TargetOpcode::KILL:
   case TargetOpcode::DBG_VALUE:
     return 0;
+  case RISCV::PseudoCALLReg:
   case RISCV::PseudoCALL:
   case RISCV::PseudoTAIL:
   case RISCV::PseudoLLA:
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
index d7bcc21f3b4..c181f3a3d05 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -870,6 +870,17 @@ def : Pat<(brind GPR:$rs1), (PseudoBRIND GPR:$rs1, 0)>;
 def : Pat<(brind (add GPR:$rs1, simm12:$imm12)),
           (PseudoBRIND GPR:$rs1, simm12:$imm12)>;
 
+// PsuedoCALLReg is a generic pseudo instruction for calls which will eventually
+// expand to auipc and jalr while encoding, with any given register used as the
+// destination.
+// Define AsmString to print "call" when compile with -S flag.
+// Define isCodeGenOnly = 0 to support parsing assembly "call" instruction.
+let isCall = 1, isBarrier = 1, isCodeGenOnly = 0, hasSideEffects = 0,
+    mayStore = 0, mayLoad = 0 in
+def PseudoCALLReg : Pseudo<(outs GPR:$rd), (ins call_symbol:$func), []> {
+  let AsmString = "call\t$rd, $func";
+}
+
 // PseudoCALL is a pseudo instruction which will eventually expand to auipc
 // and jalr while encoding. This is desirable, as an auipc+jalr pair with
 // R_RISCV_CALL and R_RISCV_RELAX relocations can be be relaxed by the linker