[llvm-branch-commits] [AllocToken, Clang] Infer type hints from sizeof expressions and casts (PR #156841)

[Marco Elver via llvm-branch-commits]

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@@ -1353,6 +1354,92 @@ void CodeGenFunction::EmitAllocToken(llvm::CallBase *CB, QualType AllocType) {
   CB->setMetadata(llvm::LLVMContext::MD_alloc_token, MDN);
 }
 
+/// Infer type from a simple sizeof expression.
+static QualType inferTypeFromSizeofExpr(const Expr *E) {
+  const Expr *Arg = E->IgnoreParenImpCasts();
+  if (const auto *UET = dyn_cast<UnaryExprOrTypeTraitExpr>(Arg)) {
+    if (UET->getKind() == UETT_SizeOf) {
+      if (UET->isArgumentType())
+        return UET->getArgumentTypeInfo()->getType();
+      else
+        return UET->getArgumentExpr()->getType();
+    }
+  }
+  return QualType();
+}
+
+/// Infer type from an arithmetic expression involving a sizeof.
+static QualType inferTypeFromArithSizeofExpr(const Expr *E) {
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melver wrote:

inferPossibleType it is.

FYI @thejh - this is probably what you'll be able to use to fill DW_AT_alloc_type  for malloc and friends for https://dwarfstd.org/issues/250407.1.html

https://github.com/llvm/llvm-project/pull/156841