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-rw-r--r--lib/Analysis/CallAndMessageChecker.cpp252
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diff --git a/lib/Analysis/CallAndMessageChecker.cpp b/lib/Analysis/CallAndMessageChecker.cpp
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--- a/lib/Analysis/CallAndMessageChecker.cpp
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-//===--- CallAndMessageChecker.cpp ------------------------------*- C++ -*--==//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This defines CallAndMessageChecker, a builtin checker that checks for various
-// errors of call and objc message expressions.
-//
-//===----------------------------------------------------------------------===//
-
-#include "clang/Basic/TargetInfo.h"
-#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
-#include "clang/Analysis/PathSensitive/BugReporter.h"
-#include "clang/AST/ParentMap.h"
-#include "GRExprEngineInternalChecks.h"
-
-using namespace clang;
-
-namespace {
-class CallAndMessageChecker
- : public CheckerVisitor<CallAndMessageChecker> {
- BugType *BT_call_null;
- BugType *BT_call_undef;
- BugType *BT_call_arg;
- BugType *BT_msg_undef;
- BugType *BT_msg_arg;
- BugType *BT_msg_ret;
-public:
- CallAndMessageChecker() :
- BT_call_null(0), BT_call_undef(0), BT_call_arg(0),
- BT_msg_undef(0), BT_msg_arg(0), BT_msg_ret(0) {}
-
- static void *getTag() {
- static int x = 0;
- return &x;
- }
-
- void PreVisitCallExpr(CheckerContext &C, const CallExpr *CE);
- void PreVisitObjCMessageExpr(CheckerContext &C, const ObjCMessageExpr *ME);
- bool EvalNilReceiver(CheckerContext &C, const ObjCMessageExpr *ME);
-
-private:
- void EmitBadCall(BugType *BT, CheckerContext &C, const CallExpr *CE);
- void EmitNilReceiverBug(CheckerContext &C, const ObjCMessageExpr *ME,
- ExplodedNode *N);
-
- void HandleNilReceiver(CheckerContext &C, const GRState *state,
- const ObjCMessageExpr *ME);
-};
-} // end anonymous namespace
-
-void clang::RegisterCallAndMessageChecker(GRExprEngine &Eng) {
- Eng.registerCheck(new CallAndMessageChecker());
-}
-
-void CallAndMessageChecker::EmitBadCall(BugType *BT, CheckerContext &C,
- const CallExpr *CE) {
- ExplodedNode *N = C.GenerateSink();
- if (!N)
- return;
-
- EnhancedBugReport *R = new EnhancedBugReport(*BT, BT->getName(), N);
- R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue,
- bugreporter::GetCalleeExpr(N));
- C.EmitReport(R);
-}
-
-void CallAndMessageChecker::PreVisitCallExpr(CheckerContext &C,
- const CallExpr *CE){
-
- const Expr *Callee = CE->getCallee()->IgnoreParens();
- SVal L = C.getState()->getSVal(Callee);
-
- if (L.isUndef()) {
- if (!BT_call_undef)
- BT_call_undef =
- new BuiltinBug("Called function pointer is an undefined pointer value");
- EmitBadCall(BT_call_undef, C, CE);
- return;
- }
-
- if (isa<loc::ConcreteInt>(L)) {
- if (!BT_call_null)
- BT_call_null =
- new BuiltinBug("Called function pointer is null (null dereference)");
- EmitBadCall(BT_call_null, C, CE);
- }
-
- for (CallExpr::const_arg_iterator I = CE->arg_begin(), E = CE->arg_end();
- I != E; ++I) {
- if (C.getState()->getSVal(*I).isUndef()) {
- if (ExplodedNode *N = C.GenerateSink()) {
- if (!BT_call_arg)
- BT_call_arg = new BuiltinBug("Pass-by-value argument in function call"
- " is undefined");
- // Generate a report for this bug.
- EnhancedBugReport *R = new EnhancedBugReport(*BT_call_arg,
- BT_call_arg->getName(), N);
- R->addRange((*I)->getSourceRange());
- R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, *I);
- C.EmitReport(R);
- return;
- }
- }
- }
-}
-
-void CallAndMessageChecker::PreVisitObjCMessageExpr(CheckerContext &C,
- const ObjCMessageExpr *ME) {
-
- const GRState *state = C.getState();
-
- if (const Expr *receiver = ME->getReceiver())
- if (state->getSVal(receiver).isUndef()) {
- if (ExplodedNode *N = C.GenerateSink()) {
- if (!BT_msg_undef)
- BT_msg_undef =
- new BuiltinBug("Receiver in message expression is a garbage value");
- EnhancedBugReport *R =
- new EnhancedBugReport(*BT_msg_undef, BT_msg_undef->getName(), N);
- R->addRange(receiver->getSourceRange());
- R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue,
- receiver);
- C.EmitReport(R);
- }
- return;
- }
-
- // Check for any arguments that are uninitialized/undefined.
- for (ObjCMessageExpr::const_arg_iterator I = ME->arg_begin(),
- E = ME->arg_end(); I != E; ++I) {
- if (state->getSVal(*I).isUndef()) {
- if (ExplodedNode *N = C.GenerateSink()) {
- if (!BT_msg_arg)
- BT_msg_arg =
- new BuiltinBug("Pass-by-value argument in message expression"
- " is undefined");
- // Generate a report for this bug.
- EnhancedBugReport *R = new EnhancedBugReport(*BT_msg_arg,
- BT_msg_arg->getName(), N);
- R->addRange((*I)->getSourceRange());
- R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, *I);
- C.EmitReport(R);
- return;
- }
- }
- }
-}
-
-bool CallAndMessageChecker::EvalNilReceiver(CheckerContext &C,
- const ObjCMessageExpr *ME) {
- HandleNilReceiver(C, C.getState(), ME);
- return true; // Nil receiver is not handled elsewhere.
-}
-
-void CallAndMessageChecker::EmitNilReceiverBug(CheckerContext &C,
- const ObjCMessageExpr *ME,
- ExplodedNode *N) {
-
- if (!BT_msg_ret)
- BT_msg_ret =
- new BuiltinBug("Receiver in message expression is "
- "'nil' and returns a garbage value");
-
- llvm::SmallString<200> buf;
- llvm::raw_svector_ostream os(buf);
- os << "The receiver of message '" << ME->getSelector().getAsString()
- << "' is nil and returns a value of type '"
- << ME->getType().getAsString() << "' that will be garbage";
-
- EnhancedBugReport *report = new EnhancedBugReport(*BT_msg_ret, os.str(), N);
- const Expr *receiver = ME->getReceiver();
- report->addRange(receiver->getSourceRange());
- report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue,
- receiver);
- C.EmitReport(report);
-}
-
-static bool SupportsNilWithFloatRet(const llvm::Triple &triple) {
- return triple.getVendor() == llvm::Triple::Apple &&
- triple.getDarwinMajorNumber() >= 9;
-}
-
-void CallAndMessageChecker::HandleNilReceiver(CheckerContext &C,
- const GRState *state,
- const ObjCMessageExpr *ME) {
-
- // Check the return type of the message expression. A message to nil will
- // return different values depending on the return type and the architecture.
- QualType RetTy = ME->getType();
-
- ASTContext &Ctx = C.getASTContext();
- CanQualType CanRetTy = Ctx.getCanonicalType(RetTy);
-
- if (CanRetTy->isStructureType()) {
- // FIXME: At some point we shouldn't rely on isConsumedExpr(), but instead
- // have the "use of undefined value" be smarter about where the
- // undefined value came from.
- if (C.getPredecessor()->getParentMap().isConsumedExpr(ME)) {
- if (ExplodedNode* N = C.GenerateSink(state))
- EmitNilReceiverBug(C, ME, N);
- return;
- }
-
- // The result is not consumed by a surrounding expression. Just propagate
- // the current state.
- C.addTransition(state);
- return;
- }
-
- // Other cases: check if the return type is smaller than void*.
- if (CanRetTy != Ctx.VoidTy &&
- C.getPredecessor()->getParentMap().isConsumedExpr(ME)) {
- // Compute: sizeof(void *) and sizeof(return type)
- const uint64_t voidPtrSize = Ctx.getTypeSize(Ctx.VoidPtrTy);
- const uint64_t returnTypeSize = Ctx.getTypeSize(CanRetTy);
-
- if (voidPtrSize < returnTypeSize &&
- !(SupportsNilWithFloatRet(Ctx.Target.getTriple()) &&
- (Ctx.FloatTy == CanRetTy ||
- Ctx.DoubleTy == CanRetTy ||
- Ctx.LongDoubleTy == CanRetTy ||
- Ctx.LongLongTy == CanRetTy))) {
- if (ExplodedNode* N = C.GenerateSink(state))
- EmitNilReceiverBug(C, ME, N);
- return;
- }
-
- // Handle the safe cases where the return value is 0 if the
- // receiver is nil.
- //
- // FIXME: For now take the conservative approach that we only
- // return null values if we *know* that the receiver is nil.
- // This is because we can have surprises like:
- //
- // ... = [[NSScreens screens] objectAtIndex:0];
- //
- // What can happen is that [... screens] could return nil, but
- // it most likely isn't nil. We should assume the semantics
- // of this case unless we have *a lot* more knowledge.
- //
- SVal V = C.getValueManager().makeZeroVal(ME->getType());
- C.GenerateNode(state->BindExpr(ME, V));
- return;
- }
-
- C.addTransition(state);
-}
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