1//===---- CheckerHelpers.cpp - Helper functions for checkers ----*- 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 defines several static functions for use in checkers.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h"
14#include "clang/AST/Decl.h"
15#include "clang/AST/Expr.h"
16#include "clang/Lex/Preprocessor.h"
17
18namespace clang {
19
20namespace ento {
21
22// Recursively find any substatements containing macros
23bool containsMacro(const Stmt *S) {
24  if (S->getBeginLoc().isMacroID())
25    return true;
26
27  if (S->getEndLoc().isMacroID())
28    return true;
29
30  for (const Stmt *Child : S->children())
31    if (Child && containsMacro(Child))
32      return true;
33
34  return false;
35}
36
37// Recursively find any substatements containing enum constants
38bool containsEnum(const Stmt *S) {
39  const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
40
41  if (DR && isa<EnumConstantDecl>(DR->getDecl()))
42    return true;
43
44  for (const Stmt *Child : S->children())
45    if (Child && containsEnum(Child))
46      return true;
47
48  return false;
49}
50
51// Recursively find any substatements containing static vars
52bool containsStaticLocal(const Stmt *S) {
53  const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(S);
54
55  if (DR)
56    if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()))
57      if (VD->isStaticLocal())
58        return true;
59
60  for (const Stmt *Child : S->children())
61    if (Child && containsStaticLocal(Child))
62      return true;
63
64  return false;
65}
66
67// Recursively find any substatements containing __builtin_offsetof
68bool containsBuiltinOffsetOf(const Stmt *S) {
69  if (isa<OffsetOfExpr>(S))
70    return true;
71
72  for (const Stmt *Child : S->children())
73    if (Child && containsBuiltinOffsetOf(Child))
74      return true;
75
76  return false;
77}
78
79// Extract lhs and rhs from assignment statement
80std::pair<const clang::VarDecl *, const clang::Expr *>
81parseAssignment(const Stmt *S) {
82  const VarDecl *VD = nullptr;
83  const Expr *RHS = nullptr;
84
85  if (auto Assign = dyn_cast_or_null<BinaryOperator>(S)) {
86    if (Assign->isAssignmentOp()) {
87      // Ordinary assignment
88      RHS = Assign->getRHS();
89      if (auto DE = dyn_cast_or_null<DeclRefExpr>(Assign->getLHS()))
90        VD = dyn_cast_or_null<VarDecl>(DE->getDecl());
91    }
92  } else if (auto PD = dyn_cast_or_null<DeclStmt>(S)) {
93    // Initialization
94    assert(PD->isSingleDecl() && "We process decls one by one");
95    VD = cast<VarDecl>(PD->getSingleDecl());
96    RHS = VD->getAnyInitializer();
97  }
98
99  return std::make_pair(VD, RHS);
100}
101
102Nullability getNullabilityAnnotation(QualType Type) {
103  const auto *AttrType = Type->getAs<AttributedType>();
104  if (!AttrType)
105    return Nullability::Unspecified;
106  if (AttrType->getAttrKind() == attr::TypeNullable)
107    return Nullability::Nullable;
108  else if (AttrType->getAttrKind() == attr::TypeNonNull)
109    return Nullability::Nonnull;
110  return Nullability::Unspecified;
111}
112
113llvm::Optional<int> tryExpandAsInteger(StringRef Macro,
114                                       const Preprocessor &PP) {
115  const auto *MacroII = PP.getIdentifierInfo(Macro);
116  if (!MacroII)
117    return llvm::None;
118  const MacroInfo *MI = PP.getMacroInfo(MacroII);
119  if (!MI)
120    return llvm::None;
121
122  // Filter out parens.
123  std::vector<Token> FilteredTokens;
124  FilteredTokens.reserve(MI->tokens().size());
125  for (auto &T : MI->tokens())
126    if (!T.isOneOf(tok::l_paren, tok::r_paren))
127      FilteredTokens.push_back(T);
128
129  // Parse an integer at the end of the macro definition.
130  const Token &T = FilteredTokens.back();
131  // FIXME: EOF macro token coming from a PCH file on macOS while marked as
132  //        literal, doesn't contain any literal data
133  if (!T.isLiteral() || !T.getLiteralData())
134    return llvm::None;
135  StringRef ValueStr = StringRef(T.getLiteralData(), T.getLength());
136  llvm::APInt IntValue;
137  constexpr unsigned AutoSenseRadix = 0;
138  if (ValueStr.getAsInteger(AutoSenseRadix, IntValue))
139    return llvm::None;
140
141  // Parse an optional minus sign.
142  size_t Size = FilteredTokens.size();
143  if (Size >= 2) {
144    if (FilteredTokens[Size - 2].is(tok::minus))
145      IntValue = -IntValue;
146  }
147
148  return IntValue.getSExtValue();
149}
150
151} // namespace ento
152} // namespace clang
153