[PATCH] D120635: [RISCV] Fix parseBareSymbol to not double-parse top-level operators

[Jessica Clarke via Phabricator via llvm-commits]

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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


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D120635

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


Index: llvm/test/MC/RISCV/rvi-pseudos.s
===================================================================
--- llvm/test/MC/RISCV/rvi-pseudos.s
+++ llvm/test/MC/RISCV/rvi-pseudos.s
@@ -187,3 +187,9 @@
 # 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
Index: llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
===================================================================
--- llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -1613,9 +1613,11 @@
     return MatchOperand_Success;
   case AsmToken::Plus:
     Opcode = MCBinaryExpr::Add;
+    getLexer().Lex();
     break;
   case AsmToken::Minus:
     Opcode = MCBinaryExpr::Sub;
+    getLexer().Lex();
     break;
   }
 


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