[analyzer] Be less pessimistic about invalidation of global variables

as a result of a call.

Problem:
Global variables, which come in from system libraries should not be
invalidated by all calls. Also, non-system globals should not be
invalidated by system calls.

Solution:
The following solution to invalidation of globals seems flexible enough
for taint (does not invalidate stdin) and should not lead to too
many false positives. We split globals into 3 classes:

* immutable - values are preserved by calls (unless the specific
global is passed in as a parameter):
     A :  Most system globals and const scalars

* invalidated by functions defined in system headers:
     B: errno

* invalidated by all other functions (note, these functions may in
turn contain system calls):
     B: errno
     C: all other globals (which are not in A nor B)

llvm-svn: 147569

1 files changed, 6 insertions, 6 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ProgramState.cpp b/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
index eac9c1c99c1..4b98ce8b0f7 100644
--- a/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ProgramState.cpp
@@ -136,20 +136,20 @@ const ProgramState *
 ProgramState::invalidateRegions(ArrayRef<const MemRegion *> Regions,
                                 const Expr *E, unsigned Count,
                                 StoreManager::InvalidatedSymbols *IS,
-                                bool invalidateGlobals) const {
+                                const CallOrObjCMessage *Call) const {
   if (!IS) {
     StoreManager::InvalidatedSymbols invalidated;
     return invalidateRegionsImpl(Regions, E, Count,
-                                 invalidated, invalidateGlobals);
+                                 invalidated, Call);
   }
-  return invalidateRegionsImpl(Regions, E, Count, *IS, invalidateGlobals);
+  return invalidateRegionsImpl(Regions, E, Count, *IS, Call);
 }
 
 const ProgramState *
 ProgramState::invalidateRegionsImpl(ArrayRef<const MemRegion *> Regions,
                                     const Expr *E, unsigned Count,
                                     StoreManager::InvalidatedSymbols &IS,
-                                    bool invalidateGlobals) const {
+                                    const CallOrObjCMessage *Call) const {
   ProgramStateManager &Mgr = getStateManager();
   SubEngine* Eng = Mgr.getOwningEngine();
  
@@ -157,14 +157,14 @@ ProgramState::invalidateRegionsImpl(ArrayRef<const MemRegion *> Regions,
     StoreManager::InvalidatedRegions Invalidated;
     const StoreRef &newStore
       = Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, IS,
-                                        invalidateGlobals, &Invalidated);
+                                        Call, &Invalidated);
     const ProgramState *newState = makeWithStore(newStore);
     return Eng->processRegionChanges(newState, &IS, Regions, Invalidated);
   }
 
   const StoreRef &newStore =
     Mgr.StoreMgr->invalidateRegions(getStore(), Regions, E, Count, IS,
-                                    invalidateGlobals, NULL);
+                                    Call, NULL);
   return makeWithStore(newStore);
 }