GRExprEngine:

- Conjure symbols at '--' and '++' unary operations
- Add utility method SVal::GetConjuredSymbolVal() and constify some arguments
  along the way.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67395 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 26 insertions, 2 deletions

diff --git a/lib/Analysis/GRExprEngine.cpp b/lib/Analysis/GRExprEngine.cpp
index 1f47bc7f33..80467ebb27 100644
--- a/lib/Analysis/GRExprEngine.cpp
+++ b/lib/Analysis/GRExprEngine.cpp
@@ -2449,7 +2449,13 @@ void GRExprEngine::VisitUnaryOperator(UnaryOperator* U, NodeTy* Pred,
       BinaryOperator::Opcode Op = U->isIncrementOp() ? BinaryOperator::Add
                                                      : BinaryOperator::Sub;
 
-      SVal Result = EvalBinOp(Op, V2, MakeConstantVal(1U, U));      
+      SVal Result = EvalBinOp(Op, V2, MakeConstantVal(1U, U));    
+      
+      // Conjure a new symbol if necessary to recover precision.
+      if (Result.isUnknown() || !getConstraintManager().canReasonAbout(Result))
+        Result = SVal::GetConjuredSymbolVal(SymMgr, Ex,
+                                            Builder->getCurrentBlockCount());
+      
       state = BindExpr(state, U, U->isPostfix() ? V2 : Result);
 
       // Perform the store.      
diff --git a/lib/Analysis/SVals.cpp b/lib/Analysis/SVals.cpp
index 3762ae5ce6..12bf795972 100644
--- a/lib/Analysis/SVals.cpp
+++ b/lib/Analysis/SVals.cpp
@@ -338,6 +338,23 @@ SVal SVal::GetRValueSymbolVal(SymbolManager& SymMgr, const MemRegion* R) {
   return UnknownVal();
 }
 
+SVal SVal::GetConjuredSymbolVal(SymbolManager &SymMgr, const Expr* E,
+                                unsigned Count) {
+
+  QualType T = E->getType();
+  
+  if (Loc::IsLocType(T)) {
+    SymbolRef Sym = SymMgr.getConjuredSymbol(E, Count);        
+    return loc::SymbolVal(Sym);
+  }
+  else if (T->isIntegerType() && T->isScalarType()) {
+    SymbolRef Sym = SymMgr.getConjuredSymbol(E, Count);        
+    return nonloc::SymbolVal(Sym);                    
+  }
+
+  return UnknownVal();
+}
+
 nonloc::LocAsInteger nonloc::LocAsInteger::Make(BasicValueFactory& Vals, Loc V,
                                                 unsigned Bits) {
   return LocAsInteger(Vals.getPersistentSValWithData(V, Bits));
diff --git a/lib/Analysis/SymbolManager.cpp b/lib/Analysis/SymbolManager.cpp
index 589178fecb..4d101f186b 100644
--- a/lib/Analysis/SymbolManager.cpp
+++ b/lib/Analysis/SymbolManager.cpp
@@ -52,7 +52,8 @@ SymbolRef SymbolManager::getRegionRValueSymbol(const MemRegion* R) {
   return SymbolCounter++;
 }
 
-SymbolRef SymbolManager::getConjuredSymbol(Stmt* E, QualType T, unsigned Count,
+SymbolRef SymbolManager::getConjuredSymbol(const Stmt* E, QualType T,
+                                           unsigned Count,
                                            const void* SymbolTag) {
   
   llvm::FoldingSetNodeID profile;