1 //= ObjCNoReturn.cpp - Handling of Cocoa APIs known not to return --*- C++ -*---
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements special handling of recognizing ObjC API hooks that
10 // do not return but aren't marked as such in API headers.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/ExprObjC.h"
16 #include "clang/Analysis/DomainSpecific/ObjCNoReturn.h"
17 
18 using namespace clang;
19 
isSubclass(const ObjCInterfaceDecl * Class,IdentifierInfo * II)20 static bool isSubclass(const ObjCInterfaceDecl *Class, IdentifierInfo *II) {
21   if (!Class)
22     return false;
23   if (Class->getIdentifier() == II)
24     return true;
25   return isSubclass(Class->getSuperClass(), II);
26 }
27 
ObjCNoReturn(ASTContext & C)28 ObjCNoReturn::ObjCNoReturn(ASTContext &C)
29   : RaiseSel(GetNullarySelector("raise", C)),
30     NSExceptionII(&C.Idents.get("NSException"))
31 {
32   // Generate selectors.
33   SmallVector<IdentifierInfo*, 3> II;
34 
35   // raise:format:
36   II.push_back(&C.Idents.get("raise"));
37   II.push_back(&C.Idents.get("format"));
38   NSExceptionInstanceRaiseSelectors[0] =
39     C.Selectors.getSelector(II.size(), &II[0]);
40 
41   // raise:format:arguments:
42   II.push_back(&C.Idents.get("arguments"));
43   NSExceptionInstanceRaiseSelectors[1] =
44     C.Selectors.getSelector(II.size(), &II[0]);
45 }
46 
47 
isImplicitNoReturn(const ObjCMessageExpr * ME)48 bool ObjCNoReturn::isImplicitNoReturn(const ObjCMessageExpr *ME) {
49   Selector S = ME->getSelector();
50 
51   if (ME->isInstanceMessage()) {
52     // Check for the "raise" message.
53     return S == RaiseSel;
54   }
55 
56   if (const ObjCInterfaceDecl *ID = ME->getReceiverInterface()) {
57     if (isSubclass(ID, NSExceptionII)) {
58       for (unsigned i = 0; i < NUM_RAISE_SELECTORS; ++i) {
59         if (S == NSExceptionInstanceRaiseSelectors[i])
60           return true;
61       }
62     }
63   }
64 
65   return false;
66 }
67