1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
//===--- MacroRepeatedSideEffectsCheck.cpp - clang-tidy--------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "MacroRepeatedSideEffectsCheck.h"
#include "clang/Basic/Builtins.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Lex/MacroArgs.h"
#include "clang/Lex/PPCallbacks.h"
#include "clang/Lex/Preprocessor.h"
namespace clang {
namespace tidy {
namespace bugprone {
namespace {
class MacroRepeatedPPCallbacks : public PPCallbacks {
public:
MacroRepeatedPPCallbacks(ClangTidyCheck &Check, Preprocessor &PP)
: Check(Check), PP(PP) {}
void MacroExpands(const Token &MacroNameTok, const MacroDefinition &MD,
SourceRange Range, const MacroArgs *Args) override;
private:
ClangTidyCheck &Check;
Preprocessor &PP;
unsigned countArgumentExpansions(const MacroInfo *MI,
const IdentifierInfo *Arg) const;
bool hasSideEffects(const Token *ResultArgToks) const;
};
} // End of anonymous namespace.
void MacroRepeatedPPCallbacks::MacroExpands(const Token &MacroNameTok,
const MacroDefinition &MD,
SourceRange Range,
const MacroArgs *Args) {
// Ignore macro argument expansions.
if (!Range.getBegin().isFileID())
return;
const MacroInfo *MI = MD.getMacroInfo();
// Bail out if the contents of the macro are containing keywords that are
// making the macro too complex.
if (std::find_if(
MI->tokens().begin(), MI->tokens().end(), [](const Token &T) {
return T.isOneOf(tok::kw_if, tok::kw_else, tok::kw_switch,
tok::kw_case, tok::kw_break, tok::kw_while,
tok::kw_do, tok::kw_for, tok::kw_continue,
tok::kw_goto, tok::kw_return);
}) != MI->tokens().end())
return;
for (unsigned ArgNo = 0U; ArgNo < MI->getNumParams(); ++ArgNo) {
const IdentifierInfo *Arg = *(MI->param_begin() + ArgNo);
const Token *ResultArgToks = Args->getUnexpArgument(ArgNo);
if (hasSideEffects(ResultArgToks) &&
countArgumentExpansions(MI, Arg) >= 2) {
Check.diag(ResultArgToks->getLocation(),
"side effects in the %ordinal0 macro argument %1 are "
"repeated in macro expansion")
<< (ArgNo + 1) << Arg;
Check.diag(MI->getDefinitionLoc(), "macro %0 defined here",
DiagnosticIDs::Note)
<< MacroNameTok.getIdentifierInfo();
}
}
}
unsigned MacroRepeatedPPCallbacks::countArgumentExpansions(
const MacroInfo *MI, const IdentifierInfo *Arg) const {
// Current argument count. When moving forward to a different control-flow
// path this can decrease.
unsigned Current = 0;
// Max argument count.
unsigned Max = 0;
bool SkipParen = false;
int SkipParenCount = 0;
// Has a __builtin_constant_p been found?
bool FoundBuiltin = false;
bool PrevTokenIsHash = false;
// Count when "?" is reached. The "Current" will get this value when the ":"
// is reached.
std::stack<unsigned, SmallVector<unsigned, 8>> CountAtQuestion;
for (const auto &T : MI->tokens()) {
// The result of __builtin_constant_p(x) is 0 if x is a macro argument
// with side effects. If we see a __builtin_constant_p(x) followed by a
// "?" "&&" or "||", then we need to reason about control flow to report
// warnings correctly. Until such reasoning is added, bail out when this
// happens.
if (FoundBuiltin && T.isOneOf(tok::question, tok::ampamp, tok::pipepipe))
return Max;
// Skip stringified tokens.
if (T.is(tok::hash)) {
PrevTokenIsHash = true;
continue;
}
if (PrevTokenIsHash) {
PrevTokenIsHash = false;
continue;
}
// Handling of ? and :.
if (T.is(tok::question)) {
CountAtQuestion.push(Current);
} else if (T.is(tok::colon)) {
if (CountAtQuestion.empty())
return 0;
Current = CountAtQuestion.top();
CountAtQuestion.pop();
}
// If current token is a parenthesis, skip it.
if (SkipParen) {
if (T.is(tok::l_paren))
SkipParenCount++;
else if (T.is(tok::r_paren))
SkipParenCount--;
SkipParen = (SkipParenCount != 0);
if (SkipParen)
continue;
}
IdentifierInfo *TII = T.getIdentifierInfo();
// If not existent, skip it.
if (TII == nullptr)
continue;
// If a __builtin_constant_p is found within the macro definition, don't
// count arguments inside the parentheses and remember that it has been
// seen in case there are "?", "&&" or "||" operators later.
if (TII->getBuiltinID() == Builtin::BI__builtin_constant_p) {
FoundBuiltin = true;
SkipParen = true;
continue;
}
// If another macro is found within the macro definition, skip the macro
// and the eventual arguments.
if (TII->hasMacroDefinition()) {
const MacroInfo *M = PP.getMacroDefinition(TII).getMacroInfo();
if (M != nullptr && M->isFunctionLike())
SkipParen = true;
continue;
}
// Count argument.
if (TII == Arg) {
Current++;
if (Current > Max)
Max = Current;
}
}
return Max;
}
bool MacroRepeatedPPCallbacks::hasSideEffects(
const Token *ResultArgToks) const {
for (; ResultArgToks->isNot(tok::eof); ++ResultArgToks) {
if (ResultArgToks->isOneOf(tok::plusplus, tok::minusminus))
return true;
}
return false;
}
void MacroRepeatedSideEffectsCheck::registerPPCallbacks(
const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
PP->addPPCallbacks(::std::make_unique<MacroRepeatedPPCallbacks>(*this, *PP));
}
} // namespace bugprone
} // namespace tidy
} // namespace clang
|
