RISCVAsmParser: Reject call foo@invalid

[MaskRay]

... instead of silently parsing and ignoring it without leaving an error
message.

While here, remove an unreachable @plt.

[llvmbot]

@llvm/pr-subscribers-mc

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

Author: Fangrui Song (MaskRay)

Changes

... instead of silently parsing and ignoring it without leaving an error
message.

While here, remove an unreachable @<!-- -->plt.

---

Full diff: https://github.com/llvm/llvm-project/pull/135509.diff

3 Files Affected:

• (modified) llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp (+2-4)
• (modified) llvm/test/MC/RISCV/function-call-invalid.s (+1)
• (modified) llvm/test/MC/RISCV/tail-call-invalid.s (+1)

diff --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
index 952587171ffce..5804706baea9b 100644
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -2070,9 +2070,6 @@ ParseStatus RISCVAsmParser::parseBareSymbol(OperandVector &Operands) {
 
   SMLoc E = SMLoc::getFromPointer(S.getPointer() + Identifier.size());
 
-  if (Identifier.consume_back("@plt"))
-    return Error(getLoc(), "'@plt' operand not valid for instruction");
-
   MCSymbol *Sym = getContext().getOrCreateSymbol(Identifier);
 
   if (Sym->isVariable()) {
@@ -2120,8 +2117,9 @@ ParseStatus RISCVAsmParser::parseCallSymbol(OperandVector &Operands) {
     Lex();
     Lex();
     StringRef PLT;
+    SMLoc Loc = getLoc();
     if (getParser().parseIdentifier(PLT) || PLT != "plt")
-      return ParseStatus::Failure;
+      return Error(Loc, "@ (except the deprecated/ignored @plt) is disallowed");
   } else if (!getLexer().peekTok().is(AsmToken::EndOfStatement)) {
     // Avoid parsing the register in `call rd, foo` as a call symbol.
     return ParseStatus::NoMatch;
diff --git a/llvm/test/MC/RISCV/function-call-invalid.s b/llvm/test/MC/RISCV/function-call-invalid.s
index 2b7a85245880d..d429c4e27ba14 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@pls # CHECK: :[[@LINE]]:10: error: @ (except the deprecated/ignored @plt) is disallowed
diff --git a/llvm/test/MC/RISCV/tail-call-invalid.s b/llvm/test/MC/RISCV/tail-call-invalid.s
index 270d84df58ac4..14ff996b2e4b1 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@pls # CHECK: :[[@LINE]]:10: error: @ (except the deprecated/ignored @plt) is disallowed

[svs-quic]

I had pushed #135324 a couple of days ago to fix the same issue. I'm happy to land either patch.

[MaskRay]

I had pushed #135324 a couple of days ago to fix the same issue. I'm happy to land either patch.

Thanks! I'll land this one (wanted to make it clear @plt is a legacy thing and test call foo@3). Let me think about the AsmBackend change.