[llvm] 6aa8521 - [RISCV] Fix parseBareSymbol to not double-parse top-level operators

[Jessica Clarke via llvm-commits]

Author: Jessica Clarke
Date: 2022-02-27T20:48:52Z
New Revision: 6aa8521fdb7a551e32927cce71ecb0c424b51955

URL: https://github.com/llvm/llvm-project/commit/6aa8521fdb7a551e32927cce71ecb0c424b51955
DIFF: https://github.com/llvm/llvm-project/commit/6aa8521fdb7a551e32927cce71ecb0c424b51955.diff

LOG: [RISCV] Fix parseBareSymbol to not double-parse top-level operators

By failing to lex the token we end up both parsing it as a binary
operator ourselves and parsing it as a unary operator when calling
parseExpression on the RHS. For plus this is harmless but for minus this
parses "foo - 4" as "foo - -4", effectively treating a top-level minus
as a plus.

Fixes https://github.com/llvm/llvm-project/issues/54105

Reviewed By: asb, MaskRay

Differential Revision: https://reviews.llvm.org/D120635

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
    llvm/test/MC/RISCV/rvi-pseudos.s

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index df1ed414d915..c3f859b2c61d 100644
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -1613,9 +1613,11 @@ OperandMatchResultTy RISCVAsmParser::parseBareSymbol(OperandVector &Operands) {
     return MatchOperand_Success;
   case AsmToken::Plus:
     Opcode = MCBinaryExpr::Add;
+    getLexer().Lex();
     break;
   case AsmToken::Minus:
     Opcode = MCBinaryExpr::Sub;
+    getLexer().Lex();
     break;
   }
 

diff  --git a/llvm/test/MC/RISCV/rvi-pseudos.s b/llvm/test/MC/RISCV/rvi-pseudos.s
index 859f5fe640f6..7a20cfc292fb 100644
--- a/llvm/test/MC/RISCV/rvi-pseudos.s
+++ b/llvm/test/MC/RISCV/rvi-pseudos.s
@@ -187,3 +187,9 @@ sw a3, zero, a4
 # CHECK: auipc a5, %pcrel_hi((255+a_symbol)-4)
 # CHECK: addi  a5, a5, %pcrel_lo(.Lpcrel_hi30)
 lla a5, (0xFF + a_symbol) - 4
+
+## Check that we don't double-parse a top-level minus.
+# CHECK: .Lpcrel_hi31:
+# CHECK: auipc a5, %pcrel_hi(a_symbol-4)
+# CHECK: addi  a5, a5, %pcrel_lo(.Lpcrel_hi31)
+lla a5, a_symbol - 4