From 3f4fad92fee80ad64f306ca5cd7f1e875c940d08 Mon Sep 17 00:00:00 2001
From: Anna Zaks <ganna@apple.com>
Date: Tue, 19 Mar 2013 22:38:09 +0000
Subject: [PATCH] [analyzer] Do not believe lazy binding when symbolic region
 types do not match
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This fixes a crash when analyzing LLVM that was exposed by r177220 (modeling of
trivial copy/move assignment operators).

When we look up a lazy binding for “Builder”, we see the direct binding of Loc at offset 0.
Previously, we believed the binding, which led to a crash. Now, we do not believe it as
the types do not match.

llvm-svn: 177453
---
 clang/lib/StaticAnalyzer/Core/RegionStore.cpp | 21 +++++++++++++++-----
 clang/test/Analysis/region-store.cpp          | 28 +++++++++++++++++++++++++++
 clang/test/Analysis/uninit-vals.m             |  8 ++------
 3 files changed, 46 insertions(+), 11 deletions(-)
 create mode 100644 clang/test/Analysis/region-store.cpp

diff --git a/clang/lib/StaticAnalyzer/Core/RegionStore.cpp b/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
index 82db23d..731c3ed 100644
--- a/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
+++ b/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -1265,6 +1265,17 @@ SVal RegionStoreManager::getBinding(RegionBindingsConstRef B, Loc L, QualType T)
   return svalBuilder.getRegionValueSymbolVal(R);
 }
 
+static QualType getUnderlyingType(const SubRegion *R) {
+  QualType RegionTy;
+  if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R))
+    RegionTy = TVR->getValueType();
+
+  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
+    RegionTy = SR->getSymbol()->getType();
+
+  return RegionTy;
+}
+
 /// Checks to see if store \p B has a lazy binding for region \p R.
 ///
 /// If \p AllowSubregionBindings is \c false, a lazy binding will be rejected
@@ -1283,11 +1294,11 @@ getExistingLazyBinding(SValBuilder &SVB, RegionBindingsConstRef B,
   if (!LCV)
     return None;
 
-  // If the LCV is for a subregion, the types won't match, and we shouldn't
-  // reuse the binding. Unfortuately we can only check this if the destination
-  // region is a TypedValueRegion.
-  if (const TypedValueRegion *TVR = dyn_cast<TypedValueRegion>(R)) {
-    QualType RegionTy = TVR->getValueType();
+  // If the LCV is for a subregion, the types might not match, and we shouldn't
+  // reuse the binding.
+  QualType RegionTy = getUnderlyingType(R);
+  if (!RegionTy.isNull() &&
+      !RegionTy->isVoidPointerType()) {
     QualType SourceRegionTy = LCV->getRegion()->getValueType();
     if (!SVB.getContext().hasSameUnqualifiedType(RegionTy, SourceRegionTy))
       return None;
diff --git a/clang/test/Analysis/region-store.cpp b/clang/test/Analysis/region-store.cpp
new file mode 100644
index 0000000..5ea5c3f
--- /dev/null
+++ b/clang/test/Analysis/region-store.cpp
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,unix -verify %s
+// expected-no-diagnostics
+
+class Loc {
+  int x;
+};
+class P1 {
+public:
+  Loc l;
+  void setLoc(Loc L) {
+    l = L;
+  }
+  
+};
+class P2 {
+public:
+  int m;
+  int accessBase() {
+    return m;
+  }
+};
+class Derived: public P1, public P2 {
+};
+int radar13445834(Derived *Builder, Loc l) {
+  Builder->setLoc(l);
+  return Builder->accessBase();
+  
+}
\ No newline at end of file
diff --git a/clang/test/Analysis/uninit-vals.m b/clang/test/Analysis/uninit-vals.m
index 6813b8e..9f611ad 100644
--- a/clang/test/Analysis/uninit-vals.m
+++ b/clang/test/Analysis/uninit-vals.m
@@ -80,12 +80,8 @@ void PR14765_incorrectBehavior(Circle *testObj) {
 
   testObj->origin = makePoint(0.0, 0.0);
 
-  // FIXME: Assigning to 'testObj->origin' kills the default binding for the
-  // whole region, meaning that we've forgotten that testObj->size should also
-  // default to 0. Tracked by <rdar://problem/12701038>.
-  // This should be TRUE.
-  clang_analyzer_eval(testObj->size == oldSize); // expected-warning{{UNKNOWN}}
-
+  clang_analyzer_eval(testObj->size == oldSize); // expected-warning{{TRUE}}
+  
   free(testObj);
 }
 
-- 
2.7.4