static analyzer: handle casts of a function to a function pointer with
a different return type. While we don't emit any errors (yet), at
least we avoid cases where we might crash because of an assertion
failure later on (when the return type differs from what is expected).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95268 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/AdjustedReturnValueChecker.cpp b/lib/Checker/AdjustedReturnValueChecker.cpp
new file mode 100644
index 0000000..898ce76
--- /dev/null
+++ b/lib/Checker/AdjustedReturnValueChecker.cpp
@@ -0,0 +1,90 @@
+//== AdjustedReturnValueChecker.cpp -----------------------------*- C++ -*--==//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines AdjustedReturnValueChecker, a simple check to see if the
+// return value of a function call is different than the one the caller thinks
+// it is.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Checker/PathSensitive/GRExprEngine.h"
+#include "clang/Checker/BugReporter/BugReporter.h"
+#include "clang/Checker/PathSensitive/CheckerVisitor.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/ADT/SmallString.h"
+
+using namespace clang;
+
+namespace {
+class AdjustedReturnValueChecker :
+ public CheckerVisitor<AdjustedReturnValueChecker> {
+public:
+ AdjustedReturnValueChecker() {}
+
+ void PostVisitCallExpr(CheckerContext &C, const CallExpr *CE);
+
+ static void *getTag() {
+ static int x = 0; return &x;
+ }
+};
+}
+
+void clang::RegisterAdjustedReturnValueChecker(GRExprEngine &Eng) {
+ Eng.registerCheck(new AdjustedReturnValueChecker());
+}
+
+void AdjustedReturnValueChecker::PostVisitCallExpr(CheckerContext &C,
+ const CallExpr *CE) {
+
+ // Fetch the signature of the called function.
+ const GRState *state = C.getState();
+
+ SVal V = state->getSVal(CE);
+ if (V.isUnknown())
+ return;
+
+ const MemRegion *callee = state->getSVal(CE->getCallee()).getAsRegion();
+ if (!callee)
+ return;
+
+ QualType actualResultTy;
+
+ if (const FunctionTextRegion *FT = dyn_cast<FunctionTextRegion>(callee)) {
+ const FunctionDecl *FD = FT->getDecl();
+ actualResultTy = FD->getResultType();
+ }
+ else if (const BlockDataRegion *BD = dyn_cast<BlockDataRegion>(callee)) {
+ const BlockTextRegion *BR = BD->getCodeRegion();
+ const BlockPointerType *BT =
+ BR->getLocationType(C.getASTContext())->getAs<BlockPointerType>();
+ const FunctionType *FT = BT->getPointeeType()->getAs<FunctionType>();
+ actualResultTy = FT->getResultType();
+ }
+
+ // Can this happen?
+ if (actualResultTy.isNull())
+ return;
+
+ // For now, ignore references.
+ if (actualResultTy->getAs<ReferenceType>())
+ return;
+
+ // Get the result type of the call.
+ QualType expectedResultTy = CE->getType();
+
+ // Are they the same?
+ if (expectedResultTy != actualResultTy) {
+ // FIXME: Do more checking and actual emit an error. At least performing
+ // the cast avoids some assertion failures elsewhere.
+ SValuator &SVator = C.getSValuator();
+ const SValuator::CastResult &R = SVator.EvalCast(V, state, expectedResultTy, actualResultTy);
+ C.GenerateNode(R.getState()->BindExpr(CE, R.getSVal()));
+ }
+}
diff --git a/lib/Checker/CMakeLists.txt b/lib/Checker/CMakeLists.txt
index 033ad33..130378a 100644
--- a/lib/Checker/CMakeLists.txt
+++ b/lib/Checker/CMakeLists.txt
@@ -1,6 +1,7 @@
set(LLVM_NO_RTTI 1)
add_clang_library(clangChecker
+ AdjustedReturnValueChecker.cpp
ArrayBoundChecker.cpp
AttrNonNullChecker.cpp
BasicConstraintManager.cpp
@@ -26,8 +27,8 @@
DivZeroChecker.cpp
Environment.cpp
ExplodedGraph.cpp
- FlatStore.cpp
FixedAddressChecker.cpp
+ FlatStore.cpp
GRBlockCounter.cpp
GRCoreEngine.cpp
GRExprEngine.cpp
diff --git a/lib/Checker/GRExprEngine.cpp b/lib/Checker/GRExprEngine.cpp
index 52e4fc1..1e16bde 100644
--- a/lib/Checker/GRExprEngine.cpp
+++ b/lib/Checker/GRExprEngine.cpp
@@ -301,6 +301,7 @@
// their associated BugType will get registered with the BugReporter
// automatically. Note that the check itself is owned by the GRExprEngine
// object.
+ RegisterAdjustedReturnValueChecker(Eng);
RegisterAttrNonNullChecker(Eng);
RegisterCallAndMessageChecker(Eng);
RegisterDereferenceChecker(Eng);
diff --git a/lib/Checker/GRExprEngineInternalChecks.h b/lib/Checker/GRExprEngineInternalChecks.h
index e2354ed..1246703 100644
--- a/lib/Checker/GRExprEngineInternalChecks.h
+++ b/lib/Checker/GRExprEngineInternalChecks.h
@@ -19,6 +19,7 @@
class GRExprEngine;
+void RegisterAdjustedReturnValueChecker(GRExprEngine &Eng);
void RegisterAttrNonNullChecker(GRExprEngine &Eng);
void RegisterDereferenceChecker(GRExprEngine &Eng);
void RegisterDivZeroChecker(GRExprEngine &Eng);