Vendor import of clang release_32 branch r168974 (effectively, 3.2 RC2):

http://llvm.org/svn/llvm-project/cfe/branches/release_32@168974

1 files changed, 92 insertions, 19 deletions

diff --git a/include/clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h b/include/clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h
index 631858d..4a78849 100644
--- a/include/clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h
+++ b/include/clang/StaticAnalyzer/Core/PathSensitive/ConstraintManager.h
@@ -16,6 +16,7 @@
 
 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
+#include "llvm/Support/SaveAndRestore.h"
 
 namespace llvm {
 class APSInt;
@@ -26,29 +27,83 @@ namespace ento {
 
 class SubEngine;
 
+class ConditionTruthVal {
+  llvm::Optional<bool> Val;
+public:
+  /// Construct a ConditionTruthVal indicating the constraint is constrained
+  /// to either true or false, depending on the boolean value provided.
+  ConditionTruthVal(bool constraint) : Val(constraint) {}
+
+  /// Construct a ConstraintVal indicating the constraint is underconstrained.
+  ConditionTruthVal() {}
+  
+  /// Return true if the constraint is perfectly constrained to 'true'.
+  bool isConstrainedTrue() const {
+    return Val.hasValue() && Val.getValue();
+  }
+
+  /// Return true if the constraint is perfectly constrained to 'false'.
+  bool isConstrainedFalse() const {
+    return Val.hasValue() && !Val.getValue();
+  }
+
+  /// Return true if the constrained is perfectly constrained.
+  bool isConstrained() const {
+    return Val.hasValue();
+  }
+
+  /// Return true if the constrained is underconstrained and we do not know
+  /// if the constraint is true of value.
+  bool isUnderconstrained() const {
+    return !Val.hasValue();
+  }
+};
+  
 class ConstraintManager {
 public:
+  ConstraintManager() : NotifyAssumeClients(true) {}
+  
   virtual ~ConstraintManager();
   virtual ProgramStateRef assume(ProgramStateRef state,
-                                     DefinedSVal Cond,
-                                     bool Assumption) = 0;
-
-  std::pair<ProgramStateRef, ProgramStateRef >
-    assumeDual(ProgramStateRef state, DefinedSVal Cond)
-  {
-    std::pair<ProgramStateRef, ProgramStateRef > res =
-      std::make_pair(assume(state, Cond, true), assume(state, Cond, false));
-
-    assert(!(!res.first && !res.second) && "System is over constrained.");
-    return res;
+                                 DefinedSVal Cond,
+                                 bool Assumption) = 0;
+
+  typedef std::pair<ProgramStateRef, ProgramStateRef> ProgramStatePair;
+
+  /// Returns a pair of states (StTrue, StFalse) where the given condition is
+  /// assumed to be true or false, respectively.
+  ProgramStatePair assumeDual(ProgramStateRef State, DefinedSVal Cond) {
+    ProgramStateRef StTrue = assume(State, Cond, true);
+
+    // If StTrue is infeasible, asserting the falseness of Cond is unnecessary
+    // because the existing constraints already establish this.
+    if (!StTrue) {
+      // FIXME: This is fairly expensive and should be disabled even in
+      // Release+Asserts builds.
+      assert(assume(State, Cond, false) && "System is over constrained.");
+      return ProgramStatePair((ProgramStateRef)NULL, State);
+    }
+
+    ProgramStateRef StFalse = assume(State, Cond, false);
+    if (!StFalse) {
+      // We are careful to return the original state, /not/ StTrue,
+      // because we want to avoid having callers generate a new node
+      // in the ExplodedGraph.
+      return ProgramStatePair(State, (ProgramStateRef)NULL);
+    }
+
+    return ProgramStatePair(StTrue, StFalse);
   }
 
+  /// \brief If a symbol is perfectly constrained to a constant, attempt
+  /// to return the concrete value.
+  ///
+  /// Note that a ConstraintManager is not obligated to return a concretized
+  /// value for a symbol, even if it is perfectly constrained.
   virtual const llvm::APSInt* getSymVal(ProgramStateRef state,
-                                        SymbolRef sym) const = 0;
-
-  virtual bool isEqual(ProgramStateRef state,
-                       SymbolRef sym,
-                       const llvm::APSInt& V) const = 0;
+                                        SymbolRef sym) const {
+    return 0;
+  }
 
   virtual ProgramStateRef removeDeadBindings(ProgramStateRef state,
                                                  SymbolReaper& SymReaper) = 0;
@@ -59,20 +114,38 @@ public:
                      const char *sep) = 0;
 
   virtual void EndPath(ProgramStateRef state) {}
+  
+  /// Convenience method to query the state to see if a symbol is null or
+  /// not null, or if neither assumption can be made.
+  ConditionTruthVal isNull(ProgramStateRef State, SymbolRef Sym) {
+    llvm::SaveAndRestore<bool> DisableNotify(NotifyAssumeClients, false);
+
+    return checkNull(State, Sym);
+  }
 
 protected:
+  /// A flag to indicate that clients should be notified of assumptions.
+  /// By default this is the case, but sometimes this needs to be restricted
+  /// to avoid infinite recursions within the ConstraintManager.
+  ///
+  /// Note that this flag allows the ConstraintManager to be re-entrant,
+  /// but not thread-safe.
+  bool NotifyAssumeClients;
+
   /// canReasonAbout - Not all ConstraintManagers can accurately reason about
   ///  all SVal values.  This method returns true if the ConstraintManager can
   ///  reasonably handle a given SVal value.  This is typically queried by
   ///  ExprEngine to determine if the value should be replaced with a
   ///  conjured symbolic value in order to recover some precision.
   virtual bool canReasonAbout(SVal X) const = 0;
+
+  /// Returns whether or not a symbol is known to be null ("true"), known to be
+  /// non-null ("false"), or may be either ("underconstrained"). 
+  virtual ConditionTruthVal checkNull(ProgramStateRef State, SymbolRef Sym);
 };
 
-ConstraintManager* CreateBasicConstraintManager(ProgramStateManager& statemgr,
-                                                SubEngine &subengine);
 ConstraintManager* CreateRangeConstraintManager(ProgramStateManager& statemgr,
-                                                SubEngine &subengine);
+                                                SubEngine *subengine);
 
 } // end GR namespace