[analyzer] Introduce clang_analyzer_dumpSvalType introspection function

In some rare cases the type of an SVal might be interesting.
This introspection function exposes this information in tests.

Reviewed By: martong

Differential Revision: https://reviews.llvm.org/D125532

Author: Balazs Benics

clang/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp

@@ -40,6 +40,7 @@ class ExprInspectionChecker
   void analyzerNumTimesReached(const CallExpr *CE, CheckerContext &C) const;
   void analyzerCrash(const CallExpr *CE, CheckerContext &C) const;
   void analyzerWarnOnDeadSymbol(const CallExpr *CE, CheckerContext &C) const;
+  void analyzerDumpSValType(const CallExpr *CE, CheckerContext &C) const;
   void analyzerDump(const CallExpr *CE, CheckerContext &C) const;
   void analyzerExplain(const CallExpr *CE, CheckerContext &C) const;
   void analyzerPrintState(const CallExpr *CE, CheckerContext &C) const;
@@ -98,6 +99,8 @@ bool ExprInspectionChecker::evalCall(const CallEvent &Call,
                 &ExprInspectionChecker::analyzerDumpExtent)
           .Case("clang_analyzer_dumpElementCount",
                 &ExprInspectionChecker::analyzerDumpElementCount)
+          .StartsWith("clang_analyzer_dumpSvalType",
+                      &ExprInspectionChecker::analyzerDumpSValType)
           .StartsWith("clang_analyzer_dump",
                       &ExprInspectionChecker::analyzerDump)
           .Case("clang_analyzer_getExtent",
@@ -255,6 +258,16 @@ void ExprInspectionChecker::analyzerExplain(const CallExpr *CE,
   reportBug(Ex.Visit(V), C);
 }
 
+void ExprInspectionChecker::analyzerDumpSValType(const CallExpr *CE,
+                                                 CheckerContext &C) const {
+  const Expr *Arg = getArgExpr(CE, C);
+  if (!Arg)
+    return;
+
+  QualType Ty = C.getSVal(Arg).getType(C.getASTContext());
+  reportBug(Ty.getAsString(), C);
+}
+
 void ExprInspectionChecker::analyzerDump(const CallExpr *CE,
                                          CheckerContext &C) const {
   const Expr *Arg = getArgExpr(CE, C);

clang/test/Analysis/expr-inspection.c

@@ -6,12 +6,16 @@
 
 void clang_analyzer_dump(int x);
 void clang_analyzer_dump_pointer(int *p);
+void clang_analyzer_dumpSvalType(int x);
+void clang_analyzer_dumpSvalType_pointer(int *p);
 void clang_analyzer_printState(void);
 void clang_analyzer_numTimesReached(void);
 
 void foo(int x) {
   clang_analyzer_dump(x); // expected-warning{{reg_$0<int x>}}
   clang_analyzer_dump(x + (-1)); // expected-warning{{(reg_$0<int x>) - 1}}
+  clang_analyzer_dumpSvalType(x); // expected-warning {{int}}
+
   int y = 1;
   for (; y < 3; ++y) {
     clang_analyzer_numTimesReached(); // expected-warning{{2}}
@@ -53,4 +57,5 @@ struct S {
 void test_field_dumps(struct S s, struct S *p) {
   clang_analyzer_dump_pointer(&s.x); // expected-warning{{&s.x}}
   clang_analyzer_dump_pointer(&p->x); // expected-warning{{&SymRegion{reg_$1<struct S * p>}.x}}
+  clang_analyzer_dumpSvalType_pointer(&s.x); // expected-warning {{int *}}
 }