[clang] 6e9a308 - [clang] Avoid calling isInSystemMacro() too often (#182217)

[via cfe-commits]

Author: Timm Baeder
Date: 2026-02-22T06:21:33+01:00
New Revision: 6e9a308a884d18315fa3cb31693718148dfa63dd

URL: https://github.com/llvm/llvm-project/commit/6e9a308a884d18315fa3cb31693718148dfa63dd
DIFF: https://github.com/llvm/llvm-project/commit/6e9a308a884d18315fa3cb31693718148dfa63dd.diff

LOG: [clang] Avoid calling isInSystemMacro() too often (#182217)

This caused a performance regression as reported in
https://github.com/llvm/llvm-project/pull/141950

Added: 
    

Modified: 
    clang/lib/Basic/DiagnosticIDs.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Basic/DiagnosticIDs.cpp b/clang/lib/Basic/DiagnosticIDs.cpp
index 804f0d9957f23..fcd2d9f34414e 100644
--- a/clang/lib/Basic/DiagnosticIDs.cpp
+++ b/clang/lib/Basic/DiagnosticIDs.cpp
@@ -570,13 +570,13 @@ DiagnosticIDs::getDiagnosticSeverity(unsigned DiagID, SourceLocation Loc,
   // We also ignore warnings due to system macros. As above, we respect the
   // ForceSystemWarnings override.
   if (State->SuppressSystemWarnings && !Diag.getForceSystemWarnings() &&
-      Loc.isValid() && SM.isInSystemMacro(Loc)) {
+      Loc.isValid()) {
 
     bool ShowInSystemMacro = true;
     if (const StaticDiagInfoRec *Rec = GetDiagInfo(DiagID))
       ShowInSystemMacro = Rec->WarnShowInSystemMacro;
 
-    if (!ShowInSystemMacro)
+    if (!ShowInSystemMacro && SM.isInSystemMacro(Loc))
       return diag::Severity::Ignored;
   }
   // Clang-diagnostics pragmas always take precedence over suppression mapping.