[PATCH] D46415: [analyzer] pr36458: Fix retrieved value cast for symbolic void pointers.

[Artem Dergachev via Phabricator via cfe-commits]

NoQ updated this revision to Diff 145260.
NoQ added a comment.

Fix test names. Add one more test, just to make sure it works.


https://reviews.llvm.org/D46415

Files:
  lib/StaticAnalyzer/Core/Store.cpp
  test/Analysis/casts.c


Index: test/Analysis/casts.c
===================================================================
--- test/Analysis/casts.c
+++ test/Analysis/casts.c
@@ -149,3 +149,25 @@
 
   clang_analyzer_eval(*((char *)y1) == *((char *) y3)); // expected-warning{{TRUE}}
 }
+
+void *getVoidPtr();
+
+void testCastVoidPtrToIntPtrThroughIntTypedAssignment() {
+  int *x;
+  (*((int *)(&x))) = (int)getVoidPtr();
+  *x = 1; // no-crash
+}
+
+void testCastUIntPtrToIntPtrThroughIntTypedAssignment() {
+  unsigned u;
+  int *x;
+  (*((int *)(&x))) = (int)&u;
+  *x = 1;
+  clang_analyzer_eval(u == 1); // expected-warning{{TRUE}}
+}
+
+void testCastVoidPtrToIntPtrThroughUIntTypedAssignment() {
+  int *x;
+  (*((int *)(&x))) = (int)(unsigned *)getVoidPtr();
+  *x = 1; // no-crash
+}
Index: lib/StaticAnalyzer/Core/Store.cpp
===================================================================
--- lib/StaticAnalyzer/Core/Store.cpp
+++ lib/StaticAnalyzer/Core/Store.cpp
@@ -378,6 +378,20 @@
   if (castTy.isNull() || V.isUnknownOrUndef())
     return V;
 
+  // When retrieving symbolic pointer and expecting a non-void pointer,
+  // wrap them into element regions of the expected type if necessary.
+  // SValBuilder::dispatchCast() doesn't do that, but it is necessary to
+  // make sure that the retrieved value makes sense, because there's no other
+  // cast in the AST that would tell us to cast it to the correct pointer type.
+  // We might need to do that for non-void pointers as well.
+  // FIXME: We really need a single good function to perform casts for us
+  // correctly every time we need it.
+  if (castTy->isPointerType() && !castTy->isVoidPointerType())
+    if (const auto *SR = dyn_cast_or_null<SymbolicRegion>(V.getAsRegion()))
+      if (SR->getSymbol()->getType().getCanonicalType() !=
+          castTy.getCanonicalType())
+        return loc::MemRegionVal(castRegion(SR, castTy));
+
   return svalBuilder.dispatchCast(V, castTy);
 }
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D46415.145260.patch
Type: text/x-patch
Size: 1944 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20180504/2b34b5a0/attachment-0001.bin>