[analyzer] Implement pointer arithmetic on constants

Patch by: Rafael Stahl!

Differential Revision: https://reviews.llvm.org/D37478

llvm-svn: 315296

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
index bb4c2a6b525..a5b5744c3fb 100644
--- a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -922,6 +922,10 @@ SVal SimpleSValBuilder::evalBinOpLN(ProgramStateRef state,
   if (rhs.isZeroConstant())
     return lhs;
 
+  // Perserve the null pointer so that it can be found by the DerefChecker.
+  if (lhs.isZeroConstant())
+    return lhs;
+
   // We are dealing with pointer arithmetic.
 
   // Handle pointer arithmetic on constant values.
@@ -937,6 +941,8 @@ SVal SimpleSValBuilder::evalBinOpLN(ProgramStateRef state,
 
       // Offset the increment by the pointer size.
       llvm::APSInt Multiplicand(rightI.getBitWidth(), /* isUnsigned */ true);
+      QualType pointeeType = resultTy->getPointeeType();
+      Multiplicand = getContext().getTypeSizeInChars(pointeeType).getQuantity();
       rightI *= Multiplicand;
 
       // Compute the adjusted pointer.