[cfe-commits] [patch] Fix CastSizeChecker to handle sizeless types

[Jordy Rose]

Casting to void* or any other pointer-to-sizeless type (e.g. function
pointers) causes a divide-by-zero error. Simple fix: check if the pointee
type size is 0 and bail out early if it is.
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Index: /Users/jordy/programming/llvm/tools/clang/lib/Checker/CastSizeChecker.cpp
===================================================================
--- /Users/jordy/programming/llvm/tools/clang/lib/Checker/CastSizeChecker.cpp	(revision 105480)
+++ /Users/jordy/programming/llvm/tools/clang/lib/Checker/CastSizeChecker.cpp	(working copy)
@@ -63,6 +63,11 @@
 
   CharUnits RegionSize = CharUnits::fromQuantity(CI->getValue().getSExtValue());
   CharUnits TypeSize = C.getASTContext().getTypeSizeInChars(ToPointeeTy);
+  
+  // void, and a few other un-sizeable types
+  if (TypeSize.isZero())
+    return;
+  
   if (RegionSize % TypeSize != 0) {
     if (ExplodedNode *N = C.GenerateSink()) {
       if (!BT)
Index: /Users/jordy/programming/llvm/tools/clang/test/Analysis/malloc.c
===================================================================
--- /Users/jordy/programming/llvm/tools/clang/test/Analysis/malloc.c	(revision 105480)
+++ /Users/jordy/programming/llvm/tools/clang/test/Analysis/malloc.c	(working copy)
@@ -75,8 +75,20 @@
 void PR7217() {
   int *buf = malloc(2); // expected-warning{{Cast a region whose size is not a multiple of the destination type size.}}
   buf[1] = 'c'; // not crash
+}
 
+void mallocCastToVoid() {
+  void *p = malloc(2);
+  const void *cp = p; // not crash
+  free(p);
 }
+
+void mallocCastToFP() {
+  void *p = malloc(2);
+  void (*fp)() = p; // not crash
+  free(p);
+}
+
 // This tests that malloc() buffers are undefined by default
 char mallocGarbage () {
 	char *buf = malloc(2);