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   // Match any integer types, unless they are passed to a printf-based API:
57   //
58   // http://google.github.io/styleguide/cppguide.html#64-bit_Portability
59   // "Where possible, avoid passing arguments of types specified by
60   // bitwidth typedefs to printf-based APIs."
61   Finder->addMatcher(typeLoc(loc(isInteger()),
62                              unless(hasAncestor(callExpr(
63                                  callee(functionDecl(hasAttr(attr::Format)))))))
64                          .bind("tl"),
65                      this);
66   IdentTable = std::make_unique<IdentifierTable>(getLangOpts());
67 }
68 
69 void IntegerTypesCheck::check(const MatchFinder::MatchResult &Result) {
70   auto TL = *Result.Nodes.getNodeAs<TypeLoc>("tl");
71   SourceLocation Loc = TL.getBeginLoc();
72 
73   if (Loc.isInvalid() || Loc.isMacroID())
74     return;
75 
76   // Look through qualification.
77   if (auto QualLoc = TL.getAs<QualifiedTypeLoc>())
78     TL = QualLoc.getUnqualifiedLoc();
79 
80   auto BuiltinLoc = TL.getAs<BuiltinTypeLoc>();
81   if (!BuiltinLoc)
82     return;
83 
84   Token Tok = getTokenAtLoc(Loc, Result, *IdentTable);
85   // Ensure the location actually points to one of the builting integral type
86   // names we're interested in. Otherwise, we might be getting this match from
87   // implicit code (e.g. an implicit assignment operator of a class containing
88   // an array of non-POD types).
89   if (!Tok.isOneOf(tok::kw_short, tok::kw_long, tok::kw_unsigned,
90                    tok::kw_signed))
91     return;
92 
93   bool IsSigned;
94   unsigned Width;
95   const TargetInfo &TargetInfo = Result.Context->getTargetInfo();
96 
97   // Look for uses of short, long, long long and their unsigned versions.
98   switch (BuiltinLoc.getTypePtr()->getKind()) {
99   case BuiltinType::Short:
100     Width = TargetInfo.getShortWidth();
101     IsSigned = true;
102     break;
103   case BuiltinType::Long:
104     Width = TargetInfo.getLongWidth();
105     IsSigned = true;
106     break;
107   case BuiltinType::LongLong:
108     Width = TargetInfo.getLongLongWidth();
109     IsSigned = true;
110     break;
111   case BuiltinType::UShort:
112     Width = TargetInfo.getShortWidth();
113     IsSigned = false;
114     break;
115   case BuiltinType::ULong:
116     Width = TargetInfo.getLongWidth();
117     IsSigned = false;
118     break;
119   case BuiltinType::ULongLong:
120     Width = TargetInfo.getLongLongWidth();
121     IsSigned = false;
122     break;
123   default:
124     return;
125   }
126 
127   // We allow "unsigned short port" as that's reasonably common and required by
128   // the sockets API.
129   const StringRef Port = "unsigned short port";
130   const char *Data = Result.SourceManager->getCharacterData(Loc);
131   if (!std::strncmp(Data, Port.data(), Port.size()) &&
132       !isAsciiIdentifierContinue(Data[Port.size()]))
133     return;
134 
135   std::string Replacement =
136       ((IsSigned ? SignedTypePrefix : UnsignedTypePrefix) + Twine(Width) +
137        TypeSuffix)
138           .str();
139 
140   // We don't add a fix-it as changing the type can easily break code,
141   // e.g. when a function requires a 'long' argument on all platforms.
142   // QualTypes are printed with implicit quotes.
143   diag(Loc, "consider replacing %0 with '%1'") << BuiltinLoc.getType()
144                                                << Replacement;
145 }
146 
147 } // namespace runtime
148 } // namespace google
149 } // namespace tidy
150 } // namespace clang
151