Newer
Older
//=- CheckNSError.cpp - Coding conventions for uses of NSError ---*- 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 a CheckNSError, a flow-insenstive check
// that determines if an Objective-C class interface correctly returns
// a non-void return type.
//
// File under feature request PR 2600.
//
//===----------------------------------------------------------------------===//
#include "clang/Analysis/LocalCheckers.h"
#include "clang/Analysis/PathSensitive/BugReporter.h"
Ted Kremenek
committed
#include "clang/Analysis/PathSensitive/GRExprEngine.h"
#include "BasicObjCFoundationChecks.h"
#include "llvm/Support/Compiler.h"
#include "clang/AST/DeclObjC.h"
Ted Kremenek
committed
#include "clang/AST/Decl.h"
#include "llvm/ADT/SmallVector.h"
using namespace clang;
Ted Kremenek
committed
namespace {
class VISIBILITY_HIDDEN NSErrorCheck : public BugTypeCacheLocation {
void EmitGRWarnings(GRBugReporter& BR);
Ted Kremenek
committed
void CheckSignature(ObjCMethodDecl& MD, QualType& ResultTy,
llvm::SmallVectorImpl<VarDecl*>& Params,
IdentifierInfo* NSErrorII);
bool CheckArgument(QualType ArgTy, IdentifierInfo* NSErrorII);
Ted Kremenek
committed
public:
void EmitWarnings(BugReporter& BR) { EmitGRWarnings(cast<GRBugReporter>(BR));}
const char* getName() const { return "NSError** null dereference"; }
};
} // end anonymous namespace
Ted Kremenek
committed
BugType* clang::CreateNSErrorCheck() {
return new NSErrorCheck();
}
Ted Kremenek
committed
void NSErrorCheck::EmitGRWarnings(GRBugReporter& BR) {
// Get the analysis engine and the exploded analysis graph.
GRExprEngine& Eng = BR.getEngine();
GRExprEngine::GraphTy& G = Eng.getGraph();
// Get the declaration of the method/function that was analyzed.
Decl& CodeDecl = G.getCodeDecl();
ObjCMethodDecl* MD = dyn_cast<ObjCMethodDecl>(&CodeDecl);
if (!MD)
return;
// Get the ASTContext, which is useful for querying type information.
ASTContext &Ctx = BR.getContext();
Ted Kremenek
committed
QualType ResultTy;
llvm::SmallVector<VarDecl*, 5> Params;
CheckSignature(*MD, ResultTy, Params, &Ctx.Idents.get("NSError"));
if (Params.empty())
return;
if (ResultTy == Ctx.VoidTy) {
BR.EmitBasicReport("Bad return type when passing NSError**",
"Method accepting NSError** argument should have "
"non-void return value to indicate that an error occurred.",
CodeDecl.getLocation());
Ted Kremenek
committed
void NSErrorCheck::CheckSignature(ObjCMethodDecl& M, QualType& ResultTy,
llvm::SmallVectorImpl<VarDecl*>& Params,
IdentifierInfo* NSErrorII) {
ResultTy = M.getResultType();
for (ObjCMethodDecl::param_iterator I=M.param_begin(),
E=M.param_end(); I!=E; ++I)
if (CheckArgument((*I)->getType(), NSErrorII))
Params.push_back(*I);
}
bool NSErrorCheck::CheckArgument(QualType ArgTy, IdentifierInfo* NSErrorII) {
const PointerType* PPT = ArgTy->getAsPointerType();
if (!PPT) return false;
const PointerType* PT = PPT->getPointeeType()->getAsPointerType();
if (!PT) return false;
const ObjCInterfaceType *IT =
PT->getPointeeType()->getAsObjCInterfaceType();
if (!IT) return false;
return IT->getDecl()->getIdentifier() == NSErrorII;
}