From: Ted Kremenek <kremenek@apple.com>
Date: Mon, 15 Dec 2008 18:51:00 +0000 (+0000)
Subject: Fix regression in handling sizeof(void) in the static analyzer.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=55f7bcbda37964d3c0e8928d0e50a6e1692b7dce;p=clang

Fix regression in handling sizeof(void) in the static analyzer.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61039 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/GRExprEngine.cpp b/lib/Analysis/GRExprEngine.cpp
index d6b15b1e2c..769e4b31a6 100644
--- a/lib/Analysis/GRExprEngine.cpp
+++ b/lib/Analysis/GRExprEngine.cpp
@@ -1973,22 +1973,24 @@ void GRExprEngine::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr* Ex,
   uint64_t amt;  
   
   if (Ex->isSizeOf()) {
-
-    // FIXME: Add support for VLAs.
-    if (!T.getTypePtr()->isConstantSizeType())
+    if (T == getContext().VoidTy) {          
+      // sizeof(void) == 1 byte.
+      amt = 1;
+    }
+    else if (!T.getTypePtr()->isConstantSizeType()) {
+      // FIXME: Add support for VLAs.
       return;
-    
-    // Some code tries to take the sizeof an ObjCInterfaceType, relying that
-    // the compiler has laid out its representation.  Just report Unknown
-    // for these.
-    if (T->isObjCInterfaceType())
+    }
+    else if (T->isObjCInterfaceType()) {
+      // Some code tries to take the sizeof an ObjCInterfaceType, relying that
+      // the compiler has laid out its representation.  Just report Unknown
+      // for these.      
       return;
-    
-    amt = 1;  // Handle sizeof(void)
-    
-    if (T != getContext().VoidTy)
+    }
+    else {
+      // All other cases.
       amt = getContext().getTypeSize(T) / 8;
-    
+    }    
   }
   else  // Get alignment of the type.
     amt = getContext().getTypeAlign(T) / 8;
diff --git a/test/Analysis/misc-ps.m b/test/Analysis/misc-ps.m
index be697f8f3a..5fccf5724e 100644
--- a/test/Analysis/misc-ps.m
+++ b/test/Analysis/misc-ps.m
@@ -87,3 +87,28 @@ void check_uninit_sized_VLA() {
   int vla[x]; // expected-warning{{The expression used to specify the number of elements in the VLA 'vla' evaluates to an undefined or garbage value.}}
 }
 
+// sizeof(void)
+// - Tests a regression reported in PR 3211: http://llvm.org/bugs/show_bug.cgi?id=3211
+void handle_sizeof_void(unsigned flag) {
+  int* p = 0;
+
+  if (flag) {
+    if (sizeof(void) == 1)
+      return;
+    // Infeasible.
+    *p = 1; // no-warning
+  }
+  
+  void* q;
+  
+  if (!flag) {
+    if (sizeof(*q) == 1)
+      return;
+    // Infeasibe.
+    *p = 1; // no-warning
+  }
+    
+  // Infeasible.
+  *p = 1; // no-warning
+}
+