[analyzer] Indicate UnarySymExpr is not supported by Z3

Random testing found that the Z3 wrapper does not support UnarySymExpr,
which was added recently and not included in the original Z3 wrapper.
For now, just avoid submitting expressions to Z3 to avoid compiler crashes.

Some crash context ...

clang -cc1 -analyze -analyzer-checker=core z3-unarysymexpr.c -analyzer-constraints=z3

Unsupported expression to reason about!
UNREACHABLE executed at clang/include/clang/StaticAnalyzer/Core/PathSensitive/SMTConstraintManager.h:297!

Stack dump:
3.	<root>/clang/test/Analysis/z3-unarysymexpr.c:13:7: Error evaluating branch
 #0 <addr> llvm::sys::PrintStackTrace(llvm::raw_ostream&, int)
 #1 <addr> llvm::sys::RunSignalHandlers()
 #8 <addr> clang::ento::SimpleConstraintManager::assumeAux(
            llvm::IntrusiveRefCntPtr<clang::ento::ProgramState const>, clang::ento::NonLoc, bool)
 #9 <addr> clang::ento::SimpleConstraintManager::assume(
            llvm::IntrusiveRefCntPtr<clang::ento::ProgramState const>, clang::ento::NonLoc, bool)

Author: einvbri

clang/include/clang/StaticAnalyzer/Core/PathSensitive/SMTConstraintManager.h

@@ -278,6 +278,13 @@ class SMTConstraintManager : public clang::ento::SimpleConstraintManager {
     if (const SymbolCast *SC = dyn_cast<SymbolCast>(Sym))
       return canReasonAbout(SVB.makeSymbolVal(SC->getOperand()));
 
+    // If a UnarySymExpr is encountered, the Z3
+    // wrapper does not support those. So indicate Z3 does not
+    // support those and return.
+    if (isa<UnarySymExpr>(Sym)) {
+      return false;
+    }
+
     if (const BinarySymExpr *BSE = dyn_cast<BinarySymExpr>(Sym)) {
       if (const SymIntExpr *SIE = dyn_cast<SymIntExpr>(BSE))
         return canReasonAbout(SVB.makeSymbolVal(SIE->getLHS()));

clang/test/Analysis/z3-unarysymexpr.c

@@ -0,0 +1,15 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -verify %s \
+// RUN:  -analyzer-constraints=z3 
+
+// REQUIRES: Z3
+//
+// Previously Z3 analysis crashed when it encountered an UnarySymExpr, validate
+// that this no longer happens.
+//
+
+// expected-no-diagnostics
+int negate(int x, int y) {
+  if ( ~(x && y))
+    return 0;
+  return 1;
+}