[clang] [compiler-rt] [Sanitizers] the access size (8 bytes) exceeds the max lock-free size (4 bytes) for 32-bit (PR #125388)

[Honey Goyal via cfe-commits]

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@@ -338,6 +338,13 @@ void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("-lpthread");
   }
   const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
+    
+// Required for 64-bit atomic operations used in sanitizer runtimes 
+// (e.g., sanitizer_common's atomic utilities). On 32-bit AIX, these 
+// are not natively supported, necessitating linkage with -latomic.
+  if (Sanitize.hasAnySanitizer() && IsArch32Bit) {
+    CmdArgs.push_back("-latomic");
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honeygoyal wrote:

**2. Consistency with Community LLVM Behavior:**
Our implementation in AIX.cpp follows the established behavior in the LLVM community codebase. While IBM’s downstream has opted to centralize similar logic in clang::tools::driver::linkSanitizerRuntimeDeps, our approach isolates the AIX-specific behavior. This minimizes the risk of inadvertently impacting sanitizer handling on non-AIX targets.

https://github.com/llvm/llvm-project/pull/125388