[analyzer] Assert that nonloc::SymbolVal always wraps a non-Loc-type symbol.

haoNoQ · haoNoQ · commit d1163790c363 · 2018-07-17T00:22:27.000Z
In the current SVal hierarchy there are multiple ways of representing certain values but few are actually used and expected to be seen by the code. In particular, a value of a symbolic pointer is always represented by a loc::MemRegionVal that wraps a SymbolicRegion that wraps the pointer symbol and never by a nonloc::SymbolVal that wraps that symbol directly. Assert the aforementioned fact. Fix one minor violation of it. Differential Revision: https://reviews.llvm.org/D48205 llvm-svn: 337227
diff --git a/clang/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h b/clang/include/clang/StaticAnalyzer/Core/PathSensitive/SVals.h
@@ -343,11 +343,14 @@ class Loc : public DefinedSVal {
 
 namespace nonloc {
 
-/// Represents symbolic expression.
+/// Represents symbolic expression that isn't a location.
 class SymbolVal : public NonLoc {
 public:
   SymbolVal() = delete;
-  SymbolVal(SymbolRef sym) : NonLoc(SymbolValKind, sym) { assert(sym); }
+  SymbolVal(SymbolRef sym) : NonLoc(SymbolValKind, sym) {
+    assert(sym);
+    assert(!Loc::isLocType(sym->getType()));
+  }
 
   SymbolRef getSymbol() const {
     return (const SymExpr *) Data;
diff --git a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -1238,7 +1238,7 @@ SVal SimpleSValBuilder::simplifySVal(ProgramStateRef State, SVal V) {
 
     SVal VisitSymbolData(const SymbolData *S) {
       if (const llvm::APSInt *I =
-              SVB.getKnownValue(State, nonloc::SymbolVal(S)))
+              SVB.getKnownValue(State, SVB.makeSymbolVal(S)))
         return Loc::isLocType(S->getType()) ? (SVal)SVB.makeIntLocVal(*I)
                                             : (SVal)SVB.makeIntVal(*I);
       return SVB.makeSymbolVal(S);
