[RISCV] Support assembling @plt symbol operands

This patch allows symbols appended with @plt to parse and assemble with the
R_RISCV_CALL_PLT relocation.

Differential Revision: https://reviews.llvm.org/D55335
Patch by Lewis Revill.

llvm-svn: 357470

1 files changed, 12 insertions, 2 deletions

diff --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index b054a3d518d..6c46a401092 100644
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -291,7 +291,8 @@ public:
     if (!isImm() || evaluateConstantImm(getImm(), Imm, VK))
       return false;
     return RISCVAsmParser::classifySymbolRef(getImm(), VK, Imm) &&
-           VK == RISCVMCExpr::VK_RISCV_CALL;
+           (VK == RISCVMCExpr::VK_RISCV_CALL ||
+            VK == RISCVMCExpr::VK_RISCV_CALL_PLT);
   }
 
   bool isCSRSystemRegister() const { return isSystemRegister(); }
@@ -1142,6 +1143,11 @@ OperandMatchResultTy RISCVAsmParser::parseBareSymbol(OperandVector &Operands) {
   if (getParser().parseIdentifier(Identifier))
     return MatchOperand_ParseFail;
 
+  if (Identifier.consume_back("@plt")) {
+    Error(getLoc(), "'@plt' operand not valid for instruction");
+    return MatchOperand_ParseFail;
+  }
+
   MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
 
   if (Sym->isVariable()) {
@@ -1169,9 +1175,13 @@ OperandMatchResultTy RISCVAsmParser::parseCallSymbol(OperandVector &Operands) {
   if (getParser().parseIdentifier(Identifier))
     return MatchOperand_ParseFail;
 
+  RISCVMCExpr::VariantKind Kind = RISCVMCExpr::VK_RISCV_CALL;
+  if (Identifier.consume_back("@plt"))
+    Kind = RISCVMCExpr::VK_RISCV_CALL_PLT;
+
   MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
   Res = MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, getContext());
-  Res = RISCVMCExpr::create(Res, RISCVMCExpr::VK_RISCV_CALL, getContext());
+  Res = RISCVMCExpr::create(Res, Kind, getContext());
   Operands.push_back(RISCVOperand::createImm(Res, S, E, isRV64()));
   return MatchOperand_Success;
 }