[analyzer] Indicate UnarySymExpr is not supported by Z3 (llvm#108900)

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)

Co-authored-by: einvbri <[email protected]>

Author: vabridgers

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

@@ -278,6 +278,11 @@ class SMTConstraintManager : public clang::ento::SimpleConstraintManager {
     if (const SymbolCast *SC = dyn_cast<SymbolCast>(Sym))
       return canReasonAbout(SVB.makeSymbolVal(SC->getOperand()));
 
+    // UnarySymExpr support is not yet implemented in the Z3 wrapper.
+    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;
+}