[PATCH] D14652: [analyzer] Improve modeling of static initializers.

[Yury Gribov via cfe-commits]

ygribov created this revision.
ygribov added reviewers: zaks.anna, dcoughlin, jordan_rose.
ygribov added a subscriber: cfe-commits.

Conversions between unrelated pointer types (e.g. char * and void *) involve bitcasts which were not properly modeled in case of static initializers. The patch fixes this problem.

The problem was originally spotted by Artem Dergachev.

http://reviews.llvm.org/D14652

Files:
  lib/StaticAnalyzer/Core/SValBuilder.cpp
  test/Analysis/inline.cpp

Index: test/Analysis/inline.cpp
===================================================================
--- test/Analysis/inline.cpp
+++ test/Analysis/inline.cpp
@@ -275,7 +275,7 @@
 
     clang_analyzer_eval(defaultReferenceZero(1) == -1); // expected-warning{{TRUE}}
     clang_analyzer_eval(defaultReferenceZero() == 0); // expected-warning{{TRUE}}
-}
+  }
 
   double defaultFloatReference(const double &i = 42) {
     return -i;
@@ -300,6 +300,13 @@
     clang_analyzer_eval(defaultString("xyz") == 'y'); // expected-warning{{TRUE}}
     clang_analyzer_eval(defaultString() == 'b'); // expected-warning{{TRUE}}
   }
+
+  const void * const void_string = "abc";
+
+  void testBitcastedString() {
+    clang_analyzer_eval(0 != void_string); // expected-warning{{TRUE}}
+    clang_analyzer_eval(0 != ((char *)void_string)[1]); // expected-warning{{TRUE}}
+  }
 }
 
 namespace OperatorNew {
Index: lib/StaticAnalyzer/Core/SValBuilder.cpp
===================================================================
--- lib/StaticAnalyzer/Core/SValBuilder.cpp
+++ lib/StaticAnalyzer/Core/SValBuilder.cpp
@@ -275,11 +275,17 @@
 
   case Stmt::ImplicitCastExprClass: {
     const CastExpr *CE = cast<CastExpr>(E);
-    if (CE->getCastKind() == CK_ArrayToPointerDecay) {
-      Optional<SVal> ArrayVal = getConstantVal(CE->getSubExpr());
-      if (!ArrayVal)
+    switch (CE->getCastKind()) {
+    default:
+      break;
+    case CK_ArrayToPointerDecay:
+    case CK_BitCast: {
+      const Expr *SE = CE->getSubExpr();
+      Optional<SVal> Val = getConstantVal(SE);
+      if (!Val)
         return None;
-      return evalCast(*ArrayVal, CE->getType(), CE->getSubExpr()->getType());
+      return evalCast(*Val, CE->getType(), SE->getType());
+    }
     }
     // FALLTHROUGH
   }


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