[NFC] Fix evaluation order dependency in call arguments (#141366)
The code in `ARMAsmParser::parseDirectiveReq` passes both
`parseRegister(Reg, SRegLoc, ERegLoc)` and `SRegLoc` as arguments to
`check()`. Since function arguments are indeterminately sequenced per
C++17 [expr.call]/5, a compiler can evaluate `SRegLoc` before
`parseRegister()` executes. This means `check()` receives a null
location instead of the actual parsed source location for error
reporting.
The fix separates the calls to establish explicit sequencing, ensuring
`check()` receives the correct source location.
This issue was detected by [the CFamily analyzer for
SonarQube](https://www.sonarsource.com/knowledge/languages/cpp/). I'm
happy to provide any additional information or clarification as needed.
diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index 8c7a65a..19c417b 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -11787,9 +11787,8 @@
Parser.Lex(); // Eat the '.req' token.
MCRegister Reg;
SMLoc SRegLoc, ERegLoc;
- if (check(parseRegister(Reg, SRegLoc, ERegLoc), SRegLoc,
- "register name expected") ||
- parseEOL())
+ const bool parseResult = parseRegister(Reg, SRegLoc, ERegLoc);
+ if (check(parseResult, SRegLoc, "register name expected") || parseEOL())
return true;
if (RegisterReqs.insert(std::make_pair(Name, Reg)).first->second != Reg)
