[PATCH] D55875: [analyzer] pr38668: RegionStore: Do not attempt to cast loaded values of non-scalar types.

[Artem Dergachev via Phabricator via cfe-commits]

NoQ updated this revision to Diff 178963.
NoQ added a comment.

Remove the test change that wasn't caused by this patch.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D55875/new/

https://reviews.llvm.org/D55875

Files:
  lib/StaticAnalyzer/Core/Store.cpp
  test/Analysis/casts.c
  test/Analysis/pointer-to-member.cpp


Index: test/Analysis/pointer-to-member.cpp
===================================================================
--- test/Analysis/pointer-to-member.cpp
+++ test/Analysis/pointer-to-member.cpp
@@ -253,11 +253,10 @@
   clang_analyzer_eval(&A::y); // expected-warning{{TRUE}}
   clang_analyzer_eval(&A::z); // expected-warning{{TRUE}}
 
-  // FIXME: These should be true.
   int A::*l = &A::x, A::*m = &A::y, A::*n = &A::z;
-  clang_analyzer_eval(l); // expected-warning{{UNKNOWN}}
-  clang_analyzer_eval(m); // expected-warning{{UNKNOWN}}
-  clang_analyzer_eval(n); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(l); // expected-warning{{TRUE}}
+  clang_analyzer_eval(m); // expected-warning{{TRUE}}
+  clang_analyzer_eval(n); // expected-warning{{TRUE}}
 
   // FIXME: These should be true as well.
   A a;
Index: test/Analysis/casts.c
===================================================================
--- test/Analysis/casts.c
+++ test/Analysis/casts.c
@@ -213,3 +213,14 @@
 }
 
 #endif
+
+char no_crash_SymbolCast_of_float_type_aux(int *p) {
+  *p += 1;
+  return *p;
+}
+
+void no_crash_SymbolCast_of_float_type() {
+  extern float x;
+  char (*f)() = no_crash_SymbolCast_of_float_type_aux;
+  f(&x);
+}
Index: lib/StaticAnalyzer/Core/Store.cpp
===================================================================
--- lib/StaticAnalyzer/Core/Store.cpp
+++ lib/StaticAnalyzer/Core/Store.cpp
@@ -394,14 +394,28 @@
   return UnknownVal();
 }
 
+static bool isScalarEnoughToAttemptACast(QualType T) {
+  return T->isIntegralOrEnumerationType() || T->isAnyPointerType() ||
+         T->isReferenceType();
+}
+
 /// CastRetrievedVal - Used by subclasses of StoreManager to implement
 ///  implicit casts that arise from loads from regions that are reinterpreted
 ///  as another region.
 SVal StoreManager::CastRetrievedVal(SVal V, const TypedValueRegion *R,
-                                    QualType castTy) {
-  if (castTy.isNull() || V.isUnknownOrUndef())
+                                    QualType CastTy) {
+  if (CastTy.isNull() || V.isUnknownOrUndef())
     return V;
 
+  QualType OrigTy = R->getValueType();
+
+  if (!isScalarEnoughToAttemptACast(OrigTy) ||
+      !isScalarEnoughToAttemptACast(CastTy)) {
+    if (OrigTy.getUnqualifiedType() == CastTy.getUnqualifiedType())
+      return V;
+    return UnknownVal();
+  }
+
   // When retrieving symbolic pointer and expecting a non-void pointer,
   // wrap them into element regions of the expected type if necessary.
   // SValBuilder::dispatchCast() doesn't do that, but it is necessary to
@@ -410,13 +424,13 @@
   // We might need to do that for non-void pointers as well.
   // FIXME: We really need a single good function to perform casts for us
   // correctly every time we need it.
-  if (castTy->isPointerType() && !castTy->isVoidPointerType())
+  if (CastTy->isPointerType() && !CastTy->isVoidPointerType())
     if (const auto *SR = dyn_cast_or_null<SymbolicRegion>(V.getAsRegion()))
       if (SR->getSymbol()->getType().getCanonicalType() !=
-          castTy.getCanonicalType())
-        return loc::MemRegionVal(castRegion(SR, castTy));
+          CastTy.getCanonicalType())
+        return loc::MemRegionVal(castRegion(SR, CastTy));
 
-  return svalBuilder.dispatchCast(V, castTy);
+  return svalBuilder.dispatchCast(V, CastTy);
 }
 
 SVal StoreManager::getLValueFieldOrIvar(const Decl *D, SVal Base) {


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