[clang] 99dddef - [Clang][Sema] Process warnings conditionally (#120591)

[via cfe-commits]

Author: Dmitry Chestnykh
Date: 2024-12-23T20:02:28+03:00
New Revision: 99dddef340e566e9d303010f1219f7d7d6d37a11

URL: https://github.com/llvm/llvm-project/commit/99dddef340e566e9d303010f1219f7d7d6d37a11
DIFF: https://github.com/llvm/llvm-project/commit/99dddef340e566e9d303010f1219f7d7d6d37a11.diff

LOG: [Clang][Sema] Process warnings conditionally (#120591)

There are a few functions that emit warnings related to positional
arguments in format strings. These functions use `getLocationOfByte()`
which has O(n) complexity and may lead to silent hang of compilation in
some cases. But such warnings is not widely used and actually don't emit
if user didn't pass the appropriate `-W...` flag, so if the flag is not
passed dont make the call to `EmitFormatDiagnostic` for such diags.

Fix #120462

Added: 
    

Modified: 
    clang/lib/Sema/SemaChecking.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index e703a62ff9cf18..ce846ae88c38b4 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -6591,27 +6591,33 @@ void CheckFormatHandler::HandleNonStandardConversionSpecifier(
 
 void CheckFormatHandler::HandlePosition(const char *startPos,
                                         unsigned posLen) {
-  EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
-                               getLocationOfByte(startPos),
-                               /*IsStringLocation*/true,
-                               getSpecifierRange(startPos, posLen));
+  if (!S.getDiagnostics().isIgnored(
+          diag::warn_format_non_standard_positional_arg, SourceLocation()))
+    EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg),
+                         getLocationOfByte(startPos),
+                         /*IsStringLocation*/ true,
+                         getSpecifierRange(startPos, posLen));
 }
 
 void CheckFormatHandler::HandleInvalidPosition(
     const char *startSpecifier, unsigned specifierLen,
     analyze_format_string::PositionContext p) {
-  EmitFormatDiagnostic(
-      S.PDiag(diag::warn_format_invalid_positional_specifier) << (unsigned)p,
-      getLocationOfByte(startSpecifier), /*IsStringLocation*/ true,
-      getSpecifierRange(startSpecifier, specifierLen));
+  if (!S.getDiagnostics().isIgnored(
+          diag::warn_format_invalid_positional_specifier, SourceLocation()))
+    EmitFormatDiagnostic(
+        S.PDiag(diag::warn_format_invalid_positional_specifier) << (unsigned)p,
+        getLocationOfByte(startSpecifier), /*IsStringLocation*/ true,
+        getSpecifierRange(startSpecifier, specifierLen));
 }
 
 void CheckFormatHandler::HandleZeroPosition(const char *startPos,
                                             unsigned posLen) {
-  EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
-                               getLocationOfByte(startPos),
-                               /*IsStringLocation*/true,
-                               getSpecifierRange(startPos, posLen));
+  if (!S.getDiagnostics().isIgnored(diag::warn_format_zero_positional_specifier,
+                                    SourceLocation()))
+    EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier),
+                         getLocationOfByte(startPos),
+                         /*IsStringLocation*/ true,
+                         getSpecifierRange(startPos, posLen));
 }
 
 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {