[clang] d6f9000 - [clang] Fix a constant evaluator crash on a NULL-type expr.

[Haojian Wu via cfe-commits]

Author: Haojian Wu
Date: 2022-04-26T10:08:30+02:00
New Revision: d6f9000ecabeca5819f4f03d774548c7cbb1ff21

URL: https://github.com/llvm/llvm-project/commit/d6f9000ecabeca5819f4f03d774548c7cbb1ff21
DIFF: https://github.com/llvm/llvm-project/commit/d6f9000ecabeca5819f4f03d774548c7cbb1ff21.diff

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

Differential Revision: https://reviews.llvm.org/D124384

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 3ad44d5e2da80..70a1e0bbd91aa 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -8631,7 +8631,7 @@ static bool evaluateLValueAsAllocSize(EvalInfo &Info, APValue::LValueBase Base,
     return false;
 
   const Expr *Init = VD->getAnyInitializer();
-  if (!Init)
+  if (!Init || Init->getType().isNull())
     return false;
 
   const Expr *E = Init->IgnoreParens();

diff  --git a/clang/test/SemaCXX/recovery-expr-type.cpp b/clang/test/SemaCXX/recovery-expr-type.cpp
index 94b275c9a362f..3db11466529e1 100644
--- a/clang/test/SemaCXX/recovery-expr-type.cpp
+++ b/clang/test/SemaCXX/recovery-expr-type.cpp
@@ -151,3 +151,13 @@ enum Circular {             // expected-note {{not complete until the closing '}
 // 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
+}
+}