1 //===--- IntegerTypesCheck.cpp - clang-tidy -------------------------------===//
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 #include "IntegerTypesCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/ASTMatchers/ASTMatchers.h"
13 #include "clang/Basic/AttrKinds.h"
14 #include "clang/Basic/CharInfo.h"
15 #include "clang/Basic/IdentifierTable.h"
16 #include "clang/Basic/TargetInfo.h"
17 #include "clang/Lex/Lexer.h"
18 
19 namespace clang {
20 
21 using namespace ast_matchers;
22 
23 static Token getTokenAtLoc(SourceLocation Loc,
24                            const MatchFinder::MatchResult &MatchResult,
25                            IdentifierTable &IdentTable) {
26   Token Tok;
27   if (Lexer::getRawToken(Loc, Tok, *MatchResult.SourceManager,
28                          MatchResult.Context->getLangOpts(), false))
29     return Tok;
30 
31   if (Tok.is(tok::raw_identifier)) {
32     IdentifierInfo &Info = IdentTable.get(Tok.getRawIdentifier());
33     Tok.setIdentifierInfo(&Info);
34     Tok.setKind(Info.getTokenID());
35   }
36   return Tok;
37 }
38 
39 namespace tidy {
40 namespace google {
41 namespace runtime {
42 
43 IntegerTypesCheck::IntegerTypesCheck(StringRef Name, ClangTidyContext *Context)
44     : ClangTidyCheck(Name, Context),
45       UnsignedTypePrefix(Options.get("UnsignedTypePrefix", "uint")),
46       SignedTypePrefix(Options.get("SignedTypePrefix", "int")),
47       TypeSuffix(Options.get("TypeSuffix", "")) {}
48 
49 void IntegerTypesCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
50   Options.store(Opts, "UnsignedTypePrefix", UnsignedTypePrefix);
51   Options.store(Opts, "SignedTypePrefix", SignedTypePrefix);
52   Options.store(Opts, "TypeSuffix", TypeSuffix);
53 }
54 
55 void IntegerTypesCheck::registerMatchers(MatchFinder *Finder) {
56   // Find all TypeLocs. The relevant Style Guide rule only applies to C++.
57   if (!getLangOpts().CPlusPlus)
58     return;
59   // Match any integer types, unless they are passed to a printf-based API:
60   //
61   // http://google.github.io/styleguide/cppguide.html#64-bit_Portability
62   // "Where possible, avoid passing arguments of types specified by
63   // bitwidth typedefs to printf-based APIs."
64   Finder->addMatcher(typeLoc(loc(isInteger()),
65                              unless(hasAncestor(callExpr(
66                                  callee(functionDecl(hasAttr(attr::Format)))))))
67                          .bind("tl"),
68                      this);
69   IdentTable = llvm::make_unique<IdentifierTable>(getLangOpts());
70 }
71 
72 void IntegerTypesCheck::check(const MatchFinder::MatchResult &Result) {
73   auto TL = *Result.Nodes.getNodeAs<TypeLoc>("tl");
74   SourceLocation Loc = TL.getBeginLoc();
75 
76   if (Loc.isInvalid() || Loc.isMacroID())
77     return;
78 
79   // Look through qualification.
80   if (auto QualLoc = TL.getAs<QualifiedTypeLoc>())
81     TL = QualLoc.getUnqualifiedLoc();
82 
83   auto BuiltinLoc = TL.getAs<BuiltinTypeLoc>();
84   if (!BuiltinLoc)
85     return;
86 
87   Token Tok = getTokenAtLoc(Loc, Result, *IdentTable);
88   // Ensure the location actually points to one of the builting integral type
89   // names we're interested in. Otherwise, we might be getting this match from
90   // implicit code (e.g. an implicit assignment operator of a class containing
91   // an array of non-POD types).
92   if (!Tok.isOneOf(tok::kw_short, tok::kw_long, tok::kw_unsigned,
93                    tok::kw_signed))
94     return;
95 
96   bool IsSigned;
97   unsigned Width;
98   const TargetInfo &TargetInfo = Result.Context->getTargetInfo();
99 
100   // Look for uses of short, long, long long and their unsigned versions.
101   switch (BuiltinLoc.getTypePtr()->getKind()) {
102   case BuiltinType::Short:
103     Width = TargetInfo.getShortWidth();
104     IsSigned = true;
105     break;
106   case BuiltinType::Long:
107     Width = TargetInfo.getLongWidth();
108     IsSigned = true;
109     break;
110   case BuiltinType::LongLong:
111     Width = TargetInfo.getLongLongWidth();
112     IsSigned = true;
113     break;
114   case BuiltinType::UShort:
115     Width = TargetInfo.getShortWidth();
116     IsSigned = false;
117     break;
118   case BuiltinType::ULong:
119     Width = TargetInfo.getLongWidth();
120     IsSigned = false;
121     break;
122   case BuiltinType::ULongLong:
123     Width = TargetInfo.getLongLongWidth();
124     IsSigned = false;
125     break;
126   default:
127     return;
128   }
129 
130   // We allow "unsigned short port" as that's reasonably common and required by
131   // the sockets API.
132   const StringRef Port = "unsigned short port";
133   const char *Data = Result.SourceManager->getCharacterData(Loc);
134   if (!std::strncmp(Data, Port.data(), Port.size()) &&
135       !isIdentifierBody(Data[Port.size()]))
136     return;
137 
138   std::string Replacement =
139       ((IsSigned ? SignedTypePrefix : UnsignedTypePrefix) + Twine(Width) +
140        TypeSuffix)
141           .str();
142 
143   // We don't add a fix-it as changing the type can easily break code,
144   // e.g. when a function requires a 'long' argument on all platforms.
145   // QualTypes are printed with implicit quotes.
146   diag(Loc, "consider replacing %0 with '%1'") << BuiltinLoc.getType()
147                                                << Replacement;
148 }
149 
150 } // namespace runtime
151 } // namespace google
152 } // namespace tidy
153 } // namespace clang
154