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1 //== CheckerContext.cpp - Context info for path-sensitive checkers-----------=//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //  This file defines CheckerContext that provides contextual info for
11 //  path-sensitive checkers.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
16 #include "clang/Basic/Builtins.h"
17 #include "clang/Lex/Lexer.h"
18 
19 using namespace clang;
20 using namespace ento;
21 
getCalleeDecl(const CallExpr * CE) const22 const FunctionDecl *CheckerContext::getCalleeDecl(const CallExpr *CE) const {
23   ProgramStateRef State = getState();
24   const Expr *Callee = CE->getCallee();
25   SVal L = State->getSVal(Callee, Pred->getLocationContext());
26   return L.getAsFunctionDecl();
27 }
28 
getCalleeName(const FunctionDecl * FunDecl) const29 StringRef CheckerContext::getCalleeName(const FunctionDecl *FunDecl) const {
30   if (!FunDecl)
31     return StringRef();
32   IdentifierInfo *funI = FunDecl->getIdentifier();
33   if (!funI)
34     return StringRef();
35   return funI->getName();
36 }
37 
38 
isCLibraryFunction(const FunctionDecl * FD,StringRef Name)39 bool CheckerContext::isCLibraryFunction(const FunctionDecl *FD,
40                                         StringRef Name) {
41   // To avoid false positives (Ex: finding user defined functions with
42   // similar names), only perform fuzzy name matching when it's a builtin.
43   // Using a string compare is slow, we might want to switch on BuiltinID here.
44   unsigned BId = FD->getBuiltinID();
45   if (BId != 0) {
46     if (Name.empty())
47       return true;
48     StringRef BName = FD->getASTContext().BuiltinInfo.getName(BId);
49     if (BName.find(Name) != StringRef::npos)
50       return true;
51   }
52 
53   const IdentifierInfo *II = FD->getIdentifier();
54   // If this is a special C++ name without IdentifierInfo, it can't be a
55   // C library function.
56   if (!II)
57     return false;
58 
59   // Look through 'extern "C"' and anything similar invented in the future.
60   const DeclContext *DC = FD->getDeclContext();
61   while (DC->isTransparentContext())
62     DC = DC->getParent();
63 
64   // If this function is in a namespace, it is not a C library function.
65   if (!DC->isTranslationUnit())
66     return false;
67 
68   // If this function is not externally visible, it is not a C library function.
69   // Note that we make an exception for inline functions, which may be
70   // declared in header files without external linkage.
71   if (!FD->isInlined() && !FD->isExternallyVisible())
72     return false;
73 
74   if (Name.empty())
75     return true;
76 
77   StringRef FName = II->getName();
78   if (FName.equals(Name))
79     return true;
80 
81   if (FName.startswith("__inline") && (FName.find(Name) != StringRef::npos))
82     return true;
83 
84   if (FName.startswith("__") && FName.endswith("_chk") &&
85       FName.find(Name) != StringRef::npos)
86     return true;
87 
88   return false;
89 }
90 
getMacroNameOrSpelling(SourceLocation & Loc)91 StringRef CheckerContext::getMacroNameOrSpelling(SourceLocation &Loc) {
92   if (Loc.isMacroID())
93     return Lexer::getImmediateMacroName(Loc, getSourceManager(),
94                                              getLangOpts());
95   SmallVector<char, 16> buf;
96   return Lexer::getSpelling(Loc, buf, getSourceManager(), getLangOpts());
97 }
98 
99