Add check for pointer arithmetic on non-array variables.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86538 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/CMakeLists.txt b/lib/Analysis/CMakeLists.txt
index 05d4ef1..1f8584d 100644
--- a/lib/Analysis/CMakeLists.txt
+++ b/lib/Analysis/CMakeLists.txt
@@ -38,6 +38,7 @@
NSAutoreleasePoolChecker.cpp
NSErrorChecker.cpp
PathDiagnostic.cpp
+ PointerArithChecker.cpp
PointerSubChecker.cpp
RangeConstraintManager.cpp
RegionStore.cpp
diff --git a/lib/Analysis/GRExprEngineInternalChecks.cpp b/lib/Analysis/GRExprEngineInternalChecks.cpp
index 41bb655..ee82969 100644
--- a/lib/Analysis/GRExprEngineInternalChecks.cpp
+++ b/lib/Analysis/GRExprEngineInternalChecks.cpp
@@ -413,6 +413,7 @@
RegisterReturnStackAddressChecker(*this);
RegisterReturnUndefChecker(*this);
RegisterPointerSubChecker(*this);
+ RegisterPointerArithChecker(*this);
RegisterFixedAddressChecker(*this);
// Note that this must be registered after ReturnStackAddressChecker.
RegisterReturnPointerRangeChecker(*this);
diff --git a/lib/Analysis/GRExprEngineInternalChecks.h b/lib/Analysis/GRExprEngineInternalChecks.h
index 4f8baad..cfbf5d7 100644
--- a/lib/Analysis/GRExprEngineInternalChecks.h
+++ b/lib/Analysis/GRExprEngineInternalChecks.h
@@ -25,6 +25,7 @@
void RegisterReturnUndefChecker(GRExprEngine &Eng);
void RegisterVLASizeChecker(GRExprEngine &Eng);
void RegisterPointerSubChecker(GRExprEngine &Eng);
+void RegisterPointerArithChecker(GRExprEngine &Eng);
void RegisterFixedAddressChecker(GRExprEngine &Eng);
void RegisterCastToStructChecker(GRExprEngine &Eng);
} // end clang namespace
diff --git a/lib/Analysis/PointerArithChecker.cpp b/lib/Analysis/PointerArithChecker.cpp
new file mode 100644
index 0000000..5f5badb
--- /dev/null
+++ b/lib/Analysis/PointerArithChecker.cpp
@@ -0,0 +1,72 @@
+//=== PointerArithChecker.cpp - Pointer arithmetic checker -----*- C++ -*--===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This files defines PointerArithChecker, a builtin checker that checks for
+// pointer arithmetic on locations other than array elements.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
+#include "GRExprEngineInternalChecks.h"
+
+using namespace clang;
+
+namespace {
+class VISIBILITY_HIDDEN PointerArithChecker
+ : public CheckerVisitor<PointerArithChecker> {
+ BuiltinBug *BT;
+public:
+ PointerArithChecker() : BT(0) {}
+ static void *getTag();
+ void PreVisitBinaryOperator(CheckerContext &C, const BinaryOperator *B);
+};
+}
+
+void *PointerArithChecker::getTag() {
+ static int x;
+ return &x;
+}
+
+void PointerArithChecker::PreVisitBinaryOperator(CheckerContext &C,
+ const BinaryOperator *B) {
+ if (B->getOpcode() != BinaryOperator::Sub &&
+ B->getOpcode() != BinaryOperator::Add)
+ return;
+
+ const GRState *state = C.getState();
+ SVal LV = state->getSVal(B->getLHS());
+ SVal RV = state->getSVal(B->getRHS());
+
+ const MemRegion *LR = LV.getAsRegion();
+
+ if (!LR || !RV.isConstant())
+ return;
+
+ // If pointer arithmetic is done on variables of non-array type, this often
+ // means behavior rely on memory organization, which is dangerous.
+ if (isa<VarRegion>(LR) || isa<CodeTextRegion>(LR) ||
+ isa<CompoundLiteralRegion>(LR)) {
+
+ if (ExplodedNode *N = C.GenerateNode(B)) {
+ if (!BT)
+ BT = new BuiltinBug("Dangerous pointer arithmetic",
+ "Pointer arithmetic done on non-array variables "
+ "means reliance on memory layout, which is "
+ "dangerous.");
+ RangedBugReport *R = new RangedBugReport(*BT,BT->getDescription().c_str(),
+ N);
+ R->addRange(B->getSourceRange());
+ C.EmitReport(R);
+ }
+ }
+}
+
+void clang::RegisterPointerArithChecker(GRExprEngine &Eng) {
+ Eng.registerCheck(new PointerArithChecker());
+}