1 //===---- CheckerHelpers.cpp - Helper functions for checkers ----*- C++ -*-===//
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 several static functions for use in checkers.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h"
15 #include "clang/AST/Decl.h"
16 #include "clang/AST/Expr.h"
17 
18 // Recursively find any substatements containing macros
containsMacro(const Stmt * S)19 bool clang::ento::containsMacro(const Stmt *S) {
20   if (S->getLocStart().isMacroID())
21     return true;
22 
23   if (S->getLocEnd().isMacroID())
24     return true;
25 
26   for (const Stmt *Child : S->children())
27     if (Child && containsMacro(Child))
28       return true;
29 
30   return false;
31 }
32 
33 // Recursively find any substatements containing enum constants
containsEnum(const Stmt * S)34 bool clang::ento::containsEnum(const Stmt *S) {
35   const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
36 
37   if (DR && isa<EnumConstantDecl>(DR->getDecl()))
38     return true;
39 
40   for (const Stmt *Child : S->children())
41     if (Child && containsEnum(Child))
42       return true;
43 
44   return false;
45 }
46 
47 // Recursively find any substatements containing static vars
containsStaticLocal(const Stmt * S)48 bool clang::ento::containsStaticLocal(const Stmt *S) {
49   const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
50 
51   if (DR)
52     if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()))
53       if (VD->isStaticLocal())
54         return true;
55 
56   for (const Stmt *Child : S->children())
57     if (Child && containsStaticLocal(Child))
58       return true;
59 
60   return false;
61 }
62 
63 // Recursively find any substatements containing __builtin_offsetof
containsBuiltinOffsetOf(const Stmt * S)64 bool clang::ento::containsBuiltinOffsetOf(const Stmt *S) {
65   if (isa<OffsetOfExpr>(S))
66     return true;
67 
68   for (const Stmt *Child : S->children())
69     if (Child && containsBuiltinOffsetOf(Child))
70       return true;
71 
72   return false;
73 }
74 
75 // Extract lhs and rhs from assignment statement
76 std::pair<const clang::VarDecl *, const clang::Expr *>
parseAssignment(const Stmt * S)77 clang::ento::parseAssignment(const Stmt *S) {
78   const VarDecl *VD = 0;
79   const Expr *RHS = 0;
80 
81   if (auto Assign = dyn_cast_or_null<BinaryOperator>(S)) {
82     if (Assign->isAssignmentOp()) {
83       // Ordinary assignment
84       RHS = Assign->getRHS();
85       if (auto DE = dyn_cast_or_null<DeclRefExpr>(Assign->getLHS()))
86         VD = dyn_cast_or_null<VarDecl>(DE->getDecl());
87     }
88   } else if (auto PD = dyn_cast_or_null<DeclStmt>(S)) {
89     // Initialization
90     assert(PD->isSingleDecl() && "We process decls one by one");
91     VD = dyn_cast_or_null<VarDecl>(PD->getSingleDecl());
92     RHS = VD->getAnyInitializer();
93   }
94 
95   return std::make_pair(VD, RHS);
96 }
97