[llvm] [RISCV] Error out on incorrectly spelt @plt on call symbols (PR #135324)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Sudharsan Veeravalli (svs-quic)

<details>
<summary>Changes</summary>

The asm parser currently accepts anything after the `@` eg. `call symbol@<!-- -->rlt` on call symbols and produces an empty object file. It would be better if we error out.

Fixes #<!-- -->135323

---
Full diff: https://github.com/llvm/llvm-project/pull/135324.diff


3 Files Affected:

- (modified) llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp (+5-2) 
- (modified) llvm/test/MC/RISCV/function-call-invalid.s (+1) 
- (modified) llvm/test/MC/RISCV/tail-call-invalid.s (+1) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index 55f1a90b2a01a..5355d38fc046d 100644
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -2123,14 +2123,18 @@ ParseStatus RISCVAsmParser::parseCallSymbol(OperandVector &Operands) {
 
   if (getLexer().getKind() != AsmToken::Identifier)
     return ParseStatus::NoMatch;
+
   std::string Identifier(getTok().getIdentifier());
+  SMLoc E = getTok().getEndLoc();
 
   if (getLexer().peekTok().is(AsmToken::At)) {
     Lex();
     Lex();
     StringRef PLT;
+    SMLoc PLTLoc = getLoc();
     if (getParser().parseIdentifier(PLT) || PLT != "plt")
-      return ParseStatus::Failure;
+      return Error(PLTLoc,
+                   "'@plt' is the only valid operand for this instruction");
   } else if (!getLexer().peekTok().is(AsmToken::EndOfStatement)) {
     // Avoid parsing the register in `call rd, foo` as a call symbol.
     return ParseStatus::NoMatch;
@@ -2138,7 +2142,6 @@ ParseStatus RISCVAsmParser::parseCallSymbol(OperandVector &Operands) {
     Lex();
   }
 
-  SMLoc E = SMLoc::getFromPointer(S.getPointer() + Identifier.size());
   RISCVMCExpr::Specifier Kind = RISCVMCExpr::VK_CALL_PLT;
 
   MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
diff --git a/llvm/test/MC/RISCV/function-call-invalid.s b/llvm/test/MC/RISCV/function-call-invalid.s
index 2b7a85245880d..358d7342c6d1f 100644
--- a/llvm/test/MC/RISCV/function-call-invalid.s
+++ b/llvm/test/MC/RISCV/function-call-invalid.s
@@ -10,3 +10,4 @@ call %lo(1234) # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
 call %hi(foo) # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
 call %lo(foo) # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
 call foo, bar # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
+call foo at rlt # CHECK: :[[@LINE]]:10: error: '@plt' is the only valid operand for this instruction
diff --git a/llvm/test/MC/RISCV/tail-call-invalid.s b/llvm/test/MC/RISCV/tail-call-invalid.s
index 270d84df58ac4..6d31354ffce1f 100644
--- a/llvm/test/MC/RISCV/tail-call-invalid.s
+++ b/llvm/test/MC/RISCV/tail-call-invalid.s
@@ -10,3 +10,4 @@ tail %hi(1234) # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
 tail %lo(1234) # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
 tail %hi(foo) # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
 tail %lo(foo) # CHECK: :[[@LINE]]:6: error: operand must be a bare symbol name
+tail foo at mlt # CHECK: :[[@LINE]]:10: error: '@plt' is the only valid operand for this instruction

``````````

</details>


https://github.com/llvm/llvm-project/pull/135324