[clang] [clang] Implement -Walloc-size diagnostic option (PR #150028)

[Erich Keane via cfe-commits]

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@@ -3542,6 +3542,59 @@ bool CallExpr::isBuiltinAssumeFalse(const ASTContext &Ctx) const {
          Arg->EvaluateAsBooleanCondition(ArgVal, Ctx) && !ArgVal;
 }
 
+const AllocSizeAttr *CallExpr::getAllocSizeAttr() const {
+  if (const FunctionDecl *DirectCallee = getDirectCallee())
+    return DirectCallee->getAttr<AllocSizeAttr>();
+  if (const Decl *IndirectCallee = getCalleeDecl())
+    return IndirectCallee->getAttr<AllocSizeAttr>();
+  return nullptr;
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erichkeane wrote:

I suspect the callee would have to do it, but we could try a little harder by 'making one up' for things like `__builtin_malloc`/etc.  Wondering if we have any other builtins... Perhaps a task for a future patch.

https://github.com/llvm/llvm-project/pull/150028