r311935 - [analyzer] Fix crash in modeling arithmetic

[Alexander Shaposhnikov via cfe-commits]

Author: alexshap
Date: Mon Aug 28 14:15:21 2017
New Revision: 311935

URL: http://llvm.org/viewvc/llvm-project?rev=311935&view=rev
Log:
[analyzer] Fix crash in modeling arithmetic

This diff fixes modeling of arithmetic 
expressions where pointers are treated as integers 
(i.e. via C-style / reinterpret casts).
For now we return UnknownVal unless the operation is a comparison.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D37120

Modified:
    cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
    cfe/trunk/test/Analysis/ptr-arith.cpp

Modified: cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp?rev=311935&r1=311934&r2=311935&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp Mon Aug 28 14:15:21 2017
@@ -360,10 +360,18 @@ SVal SimpleSValBuilder::evalBinOpNN(Prog
       Loc lhsL = lhs.castAs<nonloc::LocAsInteger>().getLoc();
       switch (rhs.getSubKind()) {
         case nonloc::LocAsIntegerKind:
+          // FIXME: at the moment the implementation 
+          // of modeling "pointers as integers" is not complete.
+          if (!BinaryOperator::isComparisonOp(op))
+            return UnknownVal();     
           return evalBinOpLL(state, op, lhsL,
                              rhs.castAs<nonloc::LocAsInteger>().getLoc(),
                              resultTy);
         case nonloc::ConcreteIntKind: {
+          // FIXME: at the moment the implementation 
+          // of modeling "pointers as integers" is not complete.
+          if (!BinaryOperator::isComparisonOp(op))
+            return UnknownVal();
           // Transform the integer into a location and compare.
           // FIXME: This only makes sense for comparisons. If we want to, say,
           // add 1 to a LocAsInteger, we'd better unpack the Loc and add to it,

Modified: cfe/trunk/test/Analysis/ptr-arith.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/ptr-arith.cpp?rev=311935&r1=311934&r2=311935&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/ptr-arith.cpp (original)
+++ cfe/trunk/test/Analysis/ptr-arith.cpp Mon Aug 28 14:15:21 2017
@@ -105,3 +105,9 @@ unsigned ptrSubtractionNoCrash(char *Beg
     return 0;
   return N;
 }
+
+// Bug 34309
+bool ptrAsIntegerSubtractionNoCrash(long x, char *p) {
+  long y = (long)p - 1;
+  return y == x;
+}