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
183
184
185
186
187
188
189
190
191
192
|
//===--- UnusedParametersCheck.cpp - clang-tidy----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "UnusedParametersCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/STLExtras.h"
#include <unordered_set>
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace misc {
namespace {
bool isOverrideMethod(const FunctionDecl *Function) {
if (const auto *MD = dyn_cast<CXXMethodDecl>(Function))
return MD->size_overridden_methods() > 0 || MD->hasAttr<OverrideAttr>();
return false;
}
} // namespace
void UnusedParametersCheck::registerMatchers(MatchFinder *Finder) {
Finder->addMatcher(
functionDecl(isDefinition(), hasBody(stmt()), hasAnyParameter(decl()))
.bind("function"),
this);
}
template <typename T>
static CharSourceRange removeNode(const MatchFinder::MatchResult &Result,
const T *PrevNode, const T *Node,
const T *NextNode) {
if (NextNode)
return CharSourceRange::getCharRange(Node->getBeginLoc(),
NextNode->getBeginLoc());
if (PrevNode)
return CharSourceRange::getTokenRange(
Lexer::getLocForEndOfToken(PrevNode->getEndLoc(), 0,
*Result.SourceManager,
Result.Context->getLangOpts()),
Node->getEndLoc());
return CharSourceRange::getTokenRange(Node->getSourceRange());
}
static FixItHint removeParameter(const MatchFinder::MatchResult &Result,
const FunctionDecl *Function, unsigned Index) {
return FixItHint::CreateRemoval(removeNode(
Result, Index > 0 ? Function->getParamDecl(Index - 1) : nullptr,
Function->getParamDecl(Index),
Index + 1 < Function->getNumParams() ? Function->getParamDecl(Index + 1)
: nullptr));
}
static FixItHint removeArgument(const MatchFinder::MatchResult &Result,
const CallExpr *Call, unsigned Index) {
return FixItHint::CreateRemoval(removeNode(
Result, Index > 0 ? Call->getArg(Index - 1) : nullptr,
Call->getArg(Index),
Index + 1 < Call->getNumArgs() ? Call->getArg(Index + 1) : nullptr));
}
class UnusedParametersCheck::IndexerVisitor
: public RecursiveASTVisitor<IndexerVisitor> {
public:
IndexerVisitor(ASTContext &Ctx) { TraverseAST(Ctx); }
const std::unordered_set<const CallExpr *> &
getFnCalls(const FunctionDecl *Fn) {
return Index[Fn->getCanonicalDecl()].Calls;
}
const std::unordered_set<const DeclRefExpr *> &
getOtherRefs(const FunctionDecl *Fn) {
return Index[Fn->getCanonicalDecl()].OtherRefs;
}
bool shouldTraversePostOrder() const { return true; }
bool WalkUpFromDeclRefExpr(DeclRefExpr *DeclRef) {
if (const auto *Fn = dyn_cast<FunctionDecl>(DeclRef->getDecl())) {
Fn = Fn->getCanonicalDecl();
Index[Fn].OtherRefs.insert(DeclRef);
}
return true;
}
bool WalkUpFromCallExpr(CallExpr *Call) {
if (const auto *Fn =
dyn_cast_or_null<FunctionDecl>(Call->getCalleeDecl())) {
Fn = Fn->getCanonicalDecl();
if (const auto *Ref =
dyn_cast<DeclRefExpr>(Call->getCallee()->IgnoreImplicit())) {
Index[Fn].OtherRefs.erase(Ref);
}
Index[Fn].Calls.insert(Call);
}
return true;
}
private:
struct IndexEntry {
std::unordered_set<const CallExpr *> Calls;
std::unordered_set<const DeclRefExpr *> OtherRefs;
};
std::unordered_map<const FunctionDecl *, IndexEntry> Index;
};
UnusedParametersCheck::~UnusedParametersCheck() = default;
UnusedParametersCheck::UnusedParametersCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
StrictMode(Options.getLocalOrGlobal("StrictMode", 0) != 0) {}
void UnusedParametersCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "StrictMode", StrictMode);
}
void UnusedParametersCheck::warnOnUnusedParameter(
const MatchFinder::MatchResult &Result, const FunctionDecl *Function,
unsigned ParamIndex) {
const auto *Param = Function->getParamDecl(ParamIndex);
auto MyDiag = diag(Param->getLocation(), "parameter %0 is unused") << Param;
if (!Indexer) {
Indexer = llvm::make_unique<IndexerVisitor>(*Result.Context);
}
// Comment out parameter name for non-local functions.
if (Function->isExternallyVisible() ||
!Result.SourceManager->isInMainFile(Function->getLocation()) ||
!Indexer->getOtherRefs(Function).empty() || isOverrideMethod(Function)) {
SourceRange RemovalRange(Param->getLocation());
// Note: We always add a space before the '/*' to not accidentally create a
// '*/*' for pointer types, which doesn't start a comment. clang-format will
// clean this up afterwards.
MyDiag << FixItHint::CreateReplacement(
RemovalRange, (Twine(" /*") + Param->getName() + "*/").str());
return;
}
// Fix all redeclarations.
for (const FunctionDecl *FD : Function->redecls())
if (FD->param_size())
MyDiag << removeParameter(Result, FD, ParamIndex);
// Fix all call sites.
for (const CallExpr *Call : Indexer->getFnCalls(Function))
if (ParamIndex < Call->getNumArgs()) // See PR38055 for example.
MyDiag << removeArgument(Result, Call, ParamIndex);
}
void UnusedParametersCheck::check(const MatchFinder::MatchResult &Result) {
const auto *Function = Result.Nodes.getNodeAs<FunctionDecl>("function");
if (!Function->hasWrittenPrototype() || Function->isTemplateInstantiation())
return;
if (const auto *Method = dyn_cast<CXXMethodDecl>(Function))
if (Method->isLambdaStaticInvoker())
return;
for (unsigned i = 0, e = Function->getNumParams(); i != e; ++i) {
const auto *Param = Function->getParamDecl(i);
if (Param->isUsed() || Param->isReferenced() || !Param->getDeclName() ||
Param->hasAttr<UnusedAttr>())
continue;
// In non-strict mode ignore function definitions with empty bodies
// (constructor initializer counts for non-empty body).
if (StrictMode ||
(Function->getBody()->child_begin() !=
Function->getBody()->child_end()) ||
(isa<CXXConstructorDecl>(Function) &&
cast<CXXConstructorDecl>(Function)->getNumCtorInitializers() > 0))
warnOnUnusedParameter(Result, Function, i);
}
}
} // namespace misc
} // namespace tidy
} // namespace clang
|
