[analyzer] Make the entries in 'Environment' context-sensitive by making entries map from

(Stmt*,LocationContext*) pairs to SVals instead of Stmt* to SVals.

This is needed to support basic IPA via inlining.  Without this, we cannot tell
if a Stmt* binding is part of the current analysis scope (StackFrameContext) or
part of a parent context.

This change introduces an uglification of the use of getSVal(), and thus takes
two steps forward and one step back.  There are also potential performance implications
of enlarging the Environment.  Both can be addressed going forward by refactoring the
APIs and optimizing the internal representation of Environment.  This patch
mainly introduces the functionality upon when we want to build upon (and clean up).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147688 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 82 insertions, 31 deletions

diff --git a/lib/StaticAnalyzer/Core/Environment.cpp b/lib/StaticAnalyzer/Core/Environment.cpp
index e1b982c08c..f43c2adc64 100644
--- a/lib/StaticAnalyzer/Core/Environment.cpp
+++ b/lib/StaticAnalyzer/Core/Environment.cpp
@@ -19,7 +19,7 @@
 using namespace clang;
 using namespace ento;
 
-SVal Environment::lookupExpr(const Stmt *E) const {
+SVal Environment::lookupExpr(const EnvironmentEntry &E) const {
   const SVal* X = ExprBindings.lookup(E);
   if (X) {
     SVal V = *X;
@@ -28,17 +28,21 @@ SVal Environment::lookupExpr(const Stmt *E) const {
   return UnknownVal();
 }
 
-SVal Environment::getSVal(const Stmt *E, SValBuilder& svalBuilder,
-			  bool useOnlyDirectBindings) const {
+SVal Environment::getSVal(const EnvironmentEntry &Entry,
+                          SValBuilder& svalBuilder,
+                          bool useOnlyDirectBindings) const {
 
   if (useOnlyDirectBindings) {
     // This branch is rarely taken, but can be exercised by
     // checkers that explicitly bind values to arbitrary
     // expressions.  It is crucial that we do not ignore any
     // expression here, and do a direct lookup.
-    return lookupExpr(E);
+    return lookupExpr(Entry);
   }
 
+  const Stmt *E = Entry.getStmt();
+  const LocationContext *LCtx = Entry.getLocationContext();
+  
   for (;;) {
     if (const Expr *Ex = dyn_cast<Expr>(E))
       E = Ex->IgnoreParens();
@@ -61,7 +65,7 @@ SVal Environment::getSVal(const Stmt *E, SValBuilder& svalBuilder,
         return svalBuilder.makeIntVal(C->getValue(), C->getType());
       }
       case Stmt::CXXBoolLiteralExprClass: {
-        const SVal *X = ExprBindings.lookup(E);
+        const SVal *X = ExprBindings.lookup(EnvironmentEntry(E, LCtx));
         if (X) 
           return *X;
         else 
@@ -69,7 +73,7 @@ SVal Environment::getSVal(const Stmt *E, SValBuilder& svalBuilder,
       }
       case Stmt::IntegerLiteralClass: {
         // In C++, this expression may have been bound to a temporary object.
-        SVal const *X = ExprBindings.lookup(E);
+        SVal const *X = ExprBindings.lookup(EnvironmentEntry(E, LCtx));
         if (X)
           return *X;
         else
@@ -93,32 +97,33 @@ SVal Environment::getSVal(const Stmt *E, SValBuilder& svalBuilder,
     };
     break;
   }
-  return lookupExpr(E);
+  return lookupExpr(EnvironmentEntry(E, LCtx));
 }
 
-Environment EnvironmentManager::bindExpr(Environment Env, const Stmt *S,
-                                         SVal V, bool Invalidate) {
-  assert(S);
-
+Environment EnvironmentManager::bindExpr(Environment Env,
+                                         const EnvironmentEntry &E,
+                                         SVal V,
+                                         bool Invalidate) {
   if (V.isUnknown()) {
     if (Invalidate)
-      return Environment(F.remove(Env.ExprBindings, S));
+      return Environment(F.remove(Env.ExprBindings, E));
     else
       return Env;
   }
-
-  return Environment(F.add(Env.ExprBindings, S, V));
+  return Environment(F.add(Env.ExprBindings, E, V));
 }
 
-static inline const Stmt *MakeLocation(const Stmt *S) {
-  return (const Stmt*) (((uintptr_t) S) | 0x1);
+static inline EnvironmentEntry MakeLocation(const EnvironmentEntry &E) {
+  const Stmt *S = E.getStmt();
+  S = (const Stmt*) (((uintptr_t) S) | 0x1);
+  return EnvironmentEntry(S, E.getLocationContext());
 }
 
 Environment EnvironmentManager::bindExprAndLocation(Environment Env,
-                                                    const Stmt *S,
+                                                    const EnvironmentEntry &E,
                                                     SVal location, SVal V) {
-  return Environment(F.add(F.add(Env.ExprBindings, MakeLocation(S), location),
-                           S, V));
+  return Environment(F.add(F.add(Env.ExprBindings, MakeLocation(E), location),
+                           E, V));
 }
 
 namespace {
@@ -130,10 +135,11 @@ public:
 };
 } // end anonymous namespace
 
-// In addition to mapping from Stmt * - > SVals in the Environment, we also
-// maintain a mapping from Stmt * -> SVals (locations) that were used during
-// a load and store.
-static inline bool IsLocation(const Stmt *S) {
+// In addition to mapping from EnvironmentEntry - > SVals in the Environment,
+// we also maintain a mapping from EnvironmentEntry -> SVals (locations)
+// that were used during a load and store.
+static inline bool IsLocation(const EnvironmentEntry &E) {
+  const Stmt *S = E.getStmt();
   return (bool) (((uintptr_t) S) & 0x1);
 }
 
@@ -154,12 +160,12 @@ EnvironmentManager::removeDeadBindings(Environment Env,
   // outnumber block-level expression bindings).
   Environment NewEnv = getInitialEnvironment();
   
-  SmallVector<std::pair<const Stmt*, SVal>, 10> deferredLocations;
+  SmallVector<std::pair<EnvironmentEntry, SVal>, 10> deferredLocations;
 
   MarkLiveCallback CB(SymReaper);
   ScanReachableSymbols RSScaner(ST, CB);
 
-  llvm::ImmutableMapRef<const Stmt*,SVal>
+  llvm::ImmutableMapRef<EnvironmentEntry,SVal>
     EBMapRef(NewEnv.ExprBindings.getRootWithoutRetain(),
              F.getTreeFactory());
 
@@ -167,7 +173,7 @@ EnvironmentManager::removeDeadBindings(Environment Env,
   for (Environment::iterator I = Env.begin(), E = Env.end();
        I != E; ++I) {
 
-    const Stmt *BlkExpr = I.getKey();
+    const EnvironmentEntry &BlkExpr = I.getKey();
     // For recorded locations (used when evaluating loads and stores), we
     // consider them live only when their associated normal expression is
     // also live.
@@ -179,7 +185,7 @@ EnvironmentManager::removeDeadBindings(Environment Env,
     }
     const SVal &X = I.getData();
 
-    if (SymReaper.isLive(BlkExpr)) {
+    if (SymReaper.isLive(BlkExpr.getStmt(), BlkExpr.getLocationContext())) {
       // Copy the binding to the new map.
       EBMapRef = EBMapRef.add(BlkExpr, X);
 
@@ -204,13 +210,58 @@ EnvironmentManager::removeDeadBindings(Environment Env,
   
   // Go through he deferred locations and add them to the new environment if
   // the correspond Stmt* is in the map as well.
-  for (SmallVectorImpl<std::pair<const Stmt*, SVal> >::iterator
+  for (SmallVectorImpl<std::pair<EnvironmentEntry, SVal> >::iterator
       I = deferredLocations.begin(), E = deferredLocations.end(); I != E; ++I) {
-    const Stmt *S = (Stmt*) (((uintptr_t) I->first) & (uintptr_t) ~0x1);
-    if (EBMapRef.lookup(S))
-      EBMapRef = EBMapRef.add(I->first, I->second);
+    const EnvironmentEntry &En = I->first;
+    const Stmt *S = (Stmt*) (((uintptr_t) En.getStmt()) & (uintptr_t) ~0x1);
+    if (EBMapRef.lookup(EnvironmentEntry(S, En.getLocationContext())))
+      EBMapRef = EBMapRef.add(En, I->second);
   }
 
   NewEnv.ExprBindings = EBMapRef.asImmutableMap();
   return NewEnv;
 }
+
+void Environment::print(raw_ostream &Out, const char *NL,
+                        const char *Sep) const {
+  printAux(Out, false, NL, Sep);
+  printAux(Out, true, NL, Sep);
+}
+  
+void Environment::printAux(raw_ostream &Out, bool printLocations,
+                           const char *NL,
+                           const char *Sep) const{
+
+  bool isFirst = true;
+
+  for (Environment::iterator I = begin(), E = end(); I != E; ++I) {
+    const EnvironmentEntry &En = I.getKey();
+    if (IsLocation(En)) {
+      if (!printLocations)
+        continue;
+    }
+    else {
+      if (printLocations)
+        continue;
+    }
+    
+    if (isFirst) {
+      Out << NL << NL
+          << (printLocations ? "Load/Store locations:" : "Expressions:")
+          << NL;      
+      isFirst = false;
+    } else {
+      Out << NL;
+    }
+    
+    const Stmt *S = En.getStmt();
+    if (printLocations) {
+      S = (Stmt*) (((uintptr_t) S) & ((uintptr_t) ~0x1));
+    }
+    
+    Out << " (" << (void*) En.getLocationContext() << ',' << (void*) S << ") ";
+    LangOptions LO; // FIXME.
+    S->printPretty(Out, 0, PrintingPolicy(LO));
+    Out << " : " << I.getData();
+  }
+}