[analyzer] teach analyzer about ObjC literals, thus trimming out a false positive with the malloc() checker involving

comparing literal addresses to nil.

Fixes <rdar://problem/10579586>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151602 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 23 insertions, 0 deletions

diff --git a/lib/StaticAnalyzer/Core/Environment.cpp b/lib/StaticAnalyzer/Core/Environment.cpp
index a44476e850..5207a506ae 100644
--- a/lib/StaticAnalyzer/Core/Environment.cpp
+++ b/lib/StaticAnalyzer/Core/Environment.cpp
@@ -90,6 +90,11 @@ SVal Environment::getSVal(const EnvironmentEntry &Entry,
         continue;
       case Stmt::ObjCPropertyRefExprClass:
         return loc::ObjCPropRef(cast<ObjCPropertyRefExpr>(E));
+      case Stmt::ObjCStringLiteralClass: {
+        MemRegionManager &MRMgr = svalBuilder.getRegionManager();
+        const ObjCStringLiteral *SL = cast<ObjCStringLiteral>(E);
+        return svalBuilder.makeLoc(MRMgr.getObjCStringRegion(SL));
+      }
       case Stmt::StringLiteralClass: {
         MemRegionManager &MRMgr = svalBuilder.getRegionManager();
         const StringLiteral *SL = cast<StringLiteral>(E);
diff --git a/lib/StaticAnalyzer/Core/MemRegion.cpp b/lib/StaticAnalyzer/Core/MemRegion.cpp
index e08a641568..d63ec94c29 100644
--- a/lib/StaticAnalyzer/Core/MemRegion.cpp
+++ b/lib/StaticAnalyzer/Core/MemRegion.cpp
@@ -262,6 +262,14 @@ void StringRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
   ID.AddPointer(superRegion);
 }
 
+void ObjCStringRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
+                                     const ObjCStringLiteral* Str,
+                                     const MemRegion* superRegion) {
+  ID.AddInteger((unsigned) ObjCStringRegionKind);
+  ID.AddPointer(Str);
+  ID.AddPointer(superRegion);
+}
+
 void AllocaRegion::ProfileRegion(llvm::FoldingSetNodeID& ID,
                                  const Expr *Ex, unsigned cnt,
                                  const MemRegion *) {
@@ -486,6 +494,10 @@ void StringRegion::dumpToStream(raw_ostream &os) const {
   Str->printPretty(os, 0, PrintingPolicy(getContext().getLangOptions()));
 }
 
+void ObjCStringRegion::dumpToStream(raw_ostream &os) const {
+  Str->printPretty(os, 0, PrintingPolicy(getContext().getLangOptions()));
+}
+
 void SymbolicRegion::dumpToStream(raw_ostream &os) const {
   os << "SymRegion{" << sym << '}';
 }
@@ -613,6 +625,11 @@ const StringRegion* MemRegionManager::getStringRegion(const StringLiteral* Str){
   return getSubRegion<StringRegion>(Str, getGlobalsRegion());
 }
 
+const ObjCStringRegion *
+MemRegionManager::getObjCStringRegion(const ObjCStringLiteral* Str){
+  return getSubRegion<ObjCStringRegion>(Str, getGlobalsRegion());
+}
+
 const VarRegion* MemRegionManager::getVarRegion(const VarDecl *D,
                                                 const LocationContext *LC) {
   const MemRegion *sReg = 0;
diff --git a/lib/StaticAnalyzer/Core/Store.cpp b/lib/StaticAnalyzer/Core/Store.cpp
index 1abac09c8f..acf5e193ab 100644
--- a/lib/StaticAnalyzer/Core/Store.cpp
+++ b/lib/StaticAnalyzer/Core/Store.cpp
@@ -120,6 +120,7 @@ const MemRegion *StoreManager::castRegion(const MemRegion *R, QualType CastToTy)
     case MemRegion::CompoundLiteralRegionKind:
     case MemRegion::FieldRegionKind:
     case MemRegion::ObjCIvarRegionKind:
+    case MemRegion::ObjCStringRegionKind:
     case MemRegion::VarRegionKind:
     case MemRegion::CXXTempObjectRegionKind:
     case MemRegion::CXXBaseObjectRegionKind: