commit 25c1d57fc906e895535fb5c7e6dde80219f353b5
author Ted Kremenek <kremenek@apple.com> Thu Sep 13 00:21:35 2012 +0000
committer Ted Kremenek <kremenek@apple.com> Thu Sep 13 00:21:35 2012 +0000
tree 4990d9c63ff9a9da198c1c082613759f8de862d9
parent 4ef19205b6912316296db74a9073ad6fa60e4cca

Teach -Wuninitialized to recognize common "noreturn" idioms in
Objective-C related to NSException.

Fixes <rdar://problem/12287498>

I debated whether or not this logic should be sunk into the CFG
itself.  It's not clear if we should, as different analyses may
wish to have different policies.  We can re-evaluate this in the
future.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163760 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/UninitializedValues.cpp

diff --git a/lib/Analysis/UninitializedValues.cpp b/lib/Analysis/UninitializedValues.cpp
index 47f2cf6..8ebee96 100644
--- a/lib/Analysis/UninitializedValues.cpp
+++ b/lib/Analysis/UninitializedValues.cpp
@@ -22,6 +22,7 @@
 #include "clang/Analysis/AnalysisContext.h"
 #include "clang/Analysis/Visitors/CFGRecStmtDeclVisitor.h"
 #include "clang/Analysis/Analyses/UninitializedValues.h"
+#include "clang/Analysis/DomainSpecific/ObjCNoReturn.h"
 #include "llvm/Support/SaveAndRestore.h"
 
 using namespace clang;
@@ -412,6 +413,7 @@
   const CFGBlock *block;
   AnalysisDeclContext ∾
   const ClassifyRefs &classification;
+  ObjCNoReturn objCNoRet;
   UninitVariablesHandler *handler;
 
 public:
@@ -420,16 +422,18 @@
                     const ClassifyRefs &classification,
                     UninitVariablesHandler *handler)
     : vals(vals), cfg(cfg), block(block), ac(ac),
-      classification(classification), handler(handler) {}
+      classification(classification), objCNoRet(ac.getASTContext()),
+      handler(handler) {}
 
   void reportUse(const Expr *ex, const VarDecl *vd);
 
-  void VisitObjCForCollectionStmt(ObjCForCollectionStmt *FS);
+  void VisitBinaryOperator(BinaryOperator *bo);
   void VisitBlockExpr(BlockExpr *be);
   void VisitCallExpr(CallExpr *ce);
-  void VisitDeclStmt(DeclStmt *ds);
   void VisitDeclRefExpr(DeclRefExpr *dr);
-  void VisitBinaryOperator(BinaryOperator *bo);
+  void VisitDeclStmt(DeclStmt *ds);
+  void VisitObjCForCollectionStmt(ObjCForCollectionStmt *FS);
+  void VisitObjCMessageExpr(ObjCMessageExpr *ME);
 
   bool isTrackedVar(const VarDecl *vd) {
     return ::isTrackedVar(vd, cast<DeclContext>(ac.getDecl()));
@@ -689,6 +693,14 @@
   }
 }
 
+void TransferFunctions::VisitObjCMessageExpr(ObjCMessageExpr *ME) {
+  // If the Objective-C message expression is an implicit no-return that
+  // is not modeled in the CFG, set the tracked dataflow values to Unknown.
+  if (objCNoRet.isImplicitNoReturn(ME)) {
+    vals.setAllScratchValues(Unknown);
+  }
+}
+
 //------------------------------------------------------------------------====//
 // High-level "driver" logic for uninitialized values analysis.
 //====------------------------------------------------------------------------//