From 9660803cd332d5c605899435019bb3b37fca3acc Mon Sep 17 00:00:00 2001
From: Ted Kremenek <kremenek@apple.com>
Date: Sun, 23 Jan 2011 17:53:04 +0000
Subject: [PATCH] Teach -Wuninitialized-experimental about sizeof().

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124076 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/UninitializedValuesV2.cpp | 10 ++++++++++
 test/Sema/uninit-variables.c           | 12 ++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/lib/Analysis/UninitializedValuesV2.cpp b/lib/Analysis/UninitializedValuesV2.cpp
index dfaff314e2..4c54885413 100644
--- a/lib/Analysis/UninitializedValuesV2.cpp
+++ b/lib/Analysis/UninitializedValuesV2.cpp
@@ -302,6 +302,7 @@ public:
   void VisitUnaryOperator(UnaryOperator *uo);
   void VisitBinaryOperator(BinaryOperator *bo);
   void VisitCastExpr(CastExpr *ce);
+  void VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *se);
 };
 }
 
@@ -435,6 +436,15 @@ void TransferFunctions::VisitCastExpr(clang::CastExpr *ce) {
   Visit(ce->getSubExpr());
 }
 
+void TransferFunctions::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *se) {
+  if (se->isSizeOf()) {
+    if (se->getType()->isConstantSizeType())
+      return;
+    // Handle VLAs.
+    Visit(se->getArgumentExpr());
+  }
+}
+
 //------------------------------------------------------------------------====//
 // High-level "driver" logic for uninitialized values analysis.
 //====------------------------------------------------------------------------//
diff --git a/test/Sema/uninit-variables.c b/test/Sema/uninit-variables.c
index aed7a70966..faf94c024b 100644
--- a/test/Sema/uninit-variables.c
+++ b/test/Sema/uninit-variables.c
@@ -180,3 +180,15 @@ MyInt test26() {
   MyInt x; // expected-warning{{use of uninitialized variable 'x'}} expected-note{{add initialization to silence this warning}}
   return x; // expected-note{{variable 'x' is possibly uninitialized when used here}}
 }
+
+// Test handling of sizeof().
+int test27() {
+  struct test_27 { int x; } *y;
+  return sizeof(y->x); // no-warning
+}
+
+int test28() {
+  int len; // expected-warning{{use of uninitialized variable 'len'}} expected-note{{add initialization to silence this warning}}
+  return sizeof(int[len]); // expected-note{{variable 'len' is possibly uninitialized when used here}}
+}
+
-- 
2.40.0