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//=- 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"
#include "clang/Analysis/PathSensitive/GRExprEngine.h"
#include "BasicObjCFoundationChecks.h"
#include "llvm/Support/Compiler.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Decl.h"
#include "llvm/ADT/SmallVector.h"
using namespace clang;
namespace {
class VISIBILITY_HIDDEN NSErrorCheck : public BugTypeCacheLocation {
void EmitGRWarnings(GRBugReporter& BR);
void CheckSignature(ObjCMethodDecl& MD, QualType& ResultTy,
llvm::SmallVectorImpl<VarDecl*>& NSErrorParams,
llvm::SmallVectorImpl<VarDecl*>& CFErrorParams,
IdentifierInfo* NSErrorII,
IdentifierInfo* CFErrorII);
void CheckSignature(FunctionDecl& MD, QualType& ResultTy,
llvm::SmallVectorImpl<VarDecl*>& NSErrorParams,
llvm::SmallVectorImpl<VarDecl*>& CFErrorParams,
IdentifierInfo* NSErrorII,
IdentifierInfo* CFErrorII);
bool CheckNSErrorArgument(QualType ArgTy, IdentifierInfo* NSErrorII);
bool CheckCFErrorArgument(QualType ArgTy, IdentifierInfo* CFErrorII);
void CheckParamDeref(VarDecl* V, GRStateRef state, GRExprEngine& Eng,
GRBugReporter& BR, bool isNErrorWarning);
void EmitRetTyWarning(BugReporter& BR, Decl& CodeDecl, bool isNSErrorWarning);
const char* desc;
const char* name;
public:
NSErrorCheck() : desc(0) {}
void EmitWarnings(BugReporter& BR) { EmitGRWarnings(cast<GRBugReporter>(BR));}
const char* getName() const { return name; }
const char* getDescription() const { return desc; }
const char* getCategory() const { return "Coding Conventions (Apple)"; }
};
} // end anonymous namespace
BugType* clang::CreateNSErrorCheck() {
return new NSErrorCheck();
}
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();
// Get the ASTContext, which is useful for querying type information.
ASTContext &Ctx = BR.getContext();
QualType ResultTy;
llvm::SmallVector<VarDecl*, 5> NSErrorParams;
llvm::SmallVector<VarDecl*, 5> CFErrorParams;
if (ObjCMethodDecl* MD = dyn_cast<ObjCMethodDecl>(&CodeDecl))
CheckSignature(*MD, ResultTy, NSErrorParams, CFErrorParams,
&Ctx.Idents.get("NSError"), &Ctx.Idents.get("CFErrorRef"));
else if (FunctionDecl* FD = dyn_cast<FunctionDecl>(&CodeDecl))
CheckSignature(*FD, ResultTy, NSErrorParams, CFErrorParams,
&Ctx.Idents.get("NSError"), &Ctx.Idents.get("CFErrorRef"));
else
return;
if (NSErrorParams.empty() && CFErrorParams.empty())
return;
if (ResultTy == Ctx.VoidTy) {
if (!NSErrorParams.empty())
EmitRetTyWarning(BR, CodeDecl, true);
if (!CFErrorParams.empty())
EmitRetTyWarning(BR, CodeDecl, false);
}
for (GRExprEngine::GraphTy::roots_iterator RI=G.roots_begin(),
RE=G.roots_end(); RI!=RE; ++RI) {
// Scan the NSError** parameters for an implicit null dereference.
for (llvm::SmallVectorImpl<VarDecl*>::iterator I=NSErrorParams.begin(),
E=NSErrorParams.end(); I!=E; ++I)
CheckParamDeref(*I, GRStateRef((*RI)->getState(), Eng.getStateManager()),
Eng, BR, true);
// Scan the CFErrorRef* parameters for an implicit null dereference.
for (llvm::SmallVectorImpl<VarDecl*>::iterator I=CFErrorParams.begin(),
E=CFErrorParams.end(); I!=E; ++I)
CheckParamDeref(*I, GRStateRef((*RI)->getState(), Eng.getStateManager()),
Eng, BR, false);
}
}
void NSErrorCheck::EmitRetTyWarning(BugReporter& BR, Decl& CodeDecl,
bool isNSErrorWarning) {
std::string msg;
llvm::raw_string_ostream os(msg);
if (isa<ObjCMethodDecl>(CodeDecl))
os << "Method";
else
os << "Function";
os << " accepting ";
os << (isNSErrorWarning ? "NSError**" : "CFErrorRef*");
os << " should have a non-void return value to indicate whether or not an "
"error occured.";
BR.EmitBasicReport(isNSErrorWarning
? "Bad return type when passing NSError**"
: "Bad return type when passing CFError*",
getCategory(), os.str().c_str(), CodeDecl.getLocation());
}
void
NSErrorCheck::CheckSignature(ObjCMethodDecl& M, QualType& ResultTy,
llvm::SmallVectorImpl<VarDecl*>& NSErrorParams,
llvm::SmallVectorImpl<VarDecl*>& CFErrorParams,
IdentifierInfo* NSErrorII,
IdentifierInfo* CFErrorII) {
ResultTy = M.getResultType();
for (ObjCMethodDecl::param_iterator I=M.param_begin(),
E=M.param_end(); I!=E; ++I) {
QualType T = (*I)->getType();
if (CheckNSErrorArgument(T, NSErrorII))
NSErrorParams.push_back(*I);
else if (CheckCFErrorArgument(T, CFErrorII))
CFErrorParams.push_back(*I);
}
}
void
NSErrorCheck::CheckSignature(FunctionDecl& F, QualType& ResultTy,
llvm::SmallVectorImpl<VarDecl*>& NSErrorParams,
llvm::SmallVectorImpl<VarDecl*>& CFErrorParams,
IdentifierInfo* NSErrorII,
IdentifierInfo* CFErrorII) {
ResultTy = F.getResultType();
for (FunctionDecl::param_iterator I=F.param_begin(),
E=F.param_end(); I!=E; ++I) {
QualType T = (*I)->getType();
if (CheckNSErrorArgument(T, NSErrorII))
NSErrorParams.push_back(*I);
else if (CheckCFErrorArgument(T, CFErrorII))
CFErrorParams.push_back(*I);
}
}
bool NSErrorCheck::CheckNSErrorArgument(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;
}
bool NSErrorCheck::CheckCFErrorArgument(QualType ArgTy,
IdentifierInfo* CFErrorII) {
const PointerType* PPT = ArgTy->getAsPointerType();
if (!PPT) return false;
const TypedefType* TT = PPT->getPointeeType()->getAsTypedefType();
if (!TT) return false;
return TT->getDecl()->getIdentifier() == CFErrorII;
}
void NSErrorCheck::CheckParamDeref(VarDecl* Param, GRStateRef rootState,
GRExprEngine& Eng, GRBugReporter& BR,
bool isNSErrorWarning) {
RVal ParamRVal = rootState.GetRVal(Eng.getLVal(Param));
// FIXME: For now assume that ParamRVal is symbolic. We need to generalize
// this later.
lval::SymbolVal* SV = dyn_cast<lval::SymbolVal>(&ParamRVal);
if (!SV) return;
// Iterate over the implicit-null dereferences.
for (GRExprEngine::null_deref_iterator I=Eng.implicit_null_derefs_begin(),
E=Eng.implicit_null_derefs_end(); I!=E; ++I) {
GRStateRef state = GRStateRef((*I)->getState(), Eng.getStateManager());
const RVal* X = state.get<GRState::NullDerefTag>();
const lval::SymbolVal* SVX = dyn_cast_or_null<lval::SymbolVal>(X);
if (!SVX || SVX->getSymbol() != SV->getSymbol()) continue
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