Introduced the notion of a "derived symbol" using the class SymbolDerived.

SymbolDerived allows us to model symbolic values that are related to other
symbols via a region hierarchy. For example, SymbolDerived can be used to model
individual values of a symbolic array.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@75728 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 44 insertions, 0 deletions

diff --git a/lib/Analysis/SymbolManager.cpp b/lib/Analysis/SymbolManager.cpp
index e59d0bd437..ab1effab2c 100644
--- a/lib/Analysis/SymbolManager.cpp
+++ b/lib/Analysis/SymbolManager.cpp
@@ -68,6 +68,11 @@ void SymbolConjured::dumpToStream(llvm::raw_ostream& os) const {
   os << "conj_$" << getSymbolID();
 }
 
+void SymbolDerived::dumpToStream(llvm::raw_ostream& os) const {
+  os << "derived_$" << getSymbolID() << '{'
+     << getParentSymbol() << ',' << getRegion() << '}';
+}
+
 void SymbolRegionValue::dumpToStream(llvm::raw_ostream& os) const {
   os << "reg_$" << getSymbolID() << "<" << R << ">";
 }
@@ -106,6 +111,24 @@ SymbolManager::getConjuredSymbol(const Stmt* E, QualType T, unsigned Count,
   return cast<SymbolConjured>(SD);
 }
 
+const SymbolDerived*
+SymbolManager::getDerivedSymbol(SymbolRef parentSymbol,
+                                const TypedRegion *R) {
+  
+  llvm::FoldingSetNodeID profile;
+  SymbolDerived::Profile(profile, parentSymbol, R);
+  void* InsertPos;  
+  SymExpr *SD = DataSet.FindNodeOrInsertPos(profile, InsertPos);  
+  if (!SD) {  
+    SD = (SymExpr*) BPAlloc.Allocate<SymbolDerived>();
+    new (SD) SymbolDerived(SymbolCounter, parentSymbol, R);
+    DataSet.InsertNode(SD, InsertPos);  
+    ++SymbolCounter;
+  }
+  
+  return cast<SymbolDerived>(SD);
+}
+
 const SymIntExpr *SymbolManager::getSymIntExpr(const SymExpr *lhs,
                                                BinaryOperator::Opcode op, 
                                                const llvm::APSInt& v,
@@ -146,6 +169,11 @@ QualType SymbolConjured::getType(ASTContext&) const {
   return T;
 }
 
+
+QualType SymbolDerived::getType(ASTContext& Ctx) const {
+  return R->getValueType(Ctx);
+}
+
 QualType SymbolRegionValue::getType(ASTContext& C) const {
   if (!T.isNull())
     return T;
diff --git a/lib/Analysis/ValueManager.cpp b/lib/Analysis/ValueManager.cpp
index 724a2e92d7..c9e24223df 100644
--- a/lib/Analysis/ValueManager.cpp
+++ b/lib/Analysis/ValueManager.cpp
@@ -118,6 +118,22 @@ SVal ValueManager::getConjuredSymbolVal(const Expr* E, QualType T,
   return UnknownVal();
 }
 
+
+SVal ValueManager::getDerivedRegionValueSymbolVal(SymbolRef parentSymbol,
+                                                  const TypedRegion *R) {
+  SymbolRef sym = SymMgr.getDerivedSymbol(parentSymbol, R);
+  
+  QualType T = R->getValueType(R->getContext());
+  
+  if (Loc::IsLocType(T))
+    return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
+  
+  if (T->isIntegerType() && T->isScalarType())
+    return nonloc::SymbolVal(sym);
+  
+  return UnknownVal();
+}
+
 SVal ValueManager::getFunctionPointer(const FunctionDecl* FD) {
   CodeTextRegion* R 
     = MemMgr.getCodeTextRegion(FD, Context.getPointerType(FD->getType()));