[clang] [compiler-rt] [UBSan] Fix incorrect alignment reported when global new returns an o… (PR #152532)

[via cfe-commits]

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@@ -1749,17 +1739,29 @@ llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
       allocator->isReservedGlobalPlacementOperator())
     result = Builder.CreateLaunderInvariantGroup(result);
 
+  // Check what type of constructor call the sanitizer is checking
+  // Different UB can occour with custom overloads of operator new
+  TypeCheckKind checkKind = CodeGenFunction::TCK_ConstructorCall;
+  const TargetInfo &TI = getContext().getTargetInfo();
+  unsigned DefaultTargetAlignment = TI.getNewAlign() / TI.getCharWidth();
+  SourceManager &SM = getContext().getSourceManager();
+  SourceLocation Loc = E->getOperatorNew()->getLocation();
+  bool IsCustomOverload = !SM.isInSystemHeader(Loc);
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gbMattN wrote:

Aha, I think I understand now. If you'd prefer than, I can remove this check, and use the new check whenever the alignment of the type is less than the system default alignment.

https://github.com/llvm/llvm-project/pull/152532