[PATCH] D124384: [clang] Fix a constant evaluator crash on a NULL-type expr.

Haojian Wu via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Mon Apr 25 06:45:56 PDT 2022


hokein created this revision.
hokein added a reviewer: sammccall.
Herald added a project: All.
hokein requested review of this revision.
Herald added a project: clang.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D124384

Files:
  clang/lib/AST/ExprConstant.cpp
  clang/test/SemaCXX/recovery-expr-type.cpp


Index: clang/test/SemaCXX/recovery-expr-type.cpp
===================================================================
--- clang/test/SemaCXX/recovery-expr-type.cpp
+++ clang/test/SemaCXX/recovery-expr-type.cpp
@@ -151,3 +151,13 @@
 // Enumerators can be evaluated (they evaluate as zero, but we don't care).
 static_assert(Circular_A == 0 && Circular_A != 0, ""); // expected-error {{static_assert failed}}
 }
+
+namespace test14 {
+extern "C" void *memset(void *, int b, unsigned long) {
+  int * const c(undef()); // expected-error {{undeclared identifier}}
+  // Verify we do not crash on evaluating *c whose initializer is a NULL-type ParenListExpr!
+  memset(c, 0, *c); // crash1
+
+  b = __builtin_object_size(c, 0); // crash2
+}
+}
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -8631,7 +8631,7 @@
     return false;
 
   const Expr *Init = VD->getAnyInitializer();
-  if (!Init)
+  if (!Init || Init->getType().isNull())
     return false;
 
   const Expr *E = Init->IgnoreParens();


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