1 //===---------- IssueHash.cpp - Generate identification hashes --*- 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 #include "clang/Analysis/IssueHash.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/AST/Decl.h"
12 #include "clang/AST/DeclCXX.h"
13 #include "clang/Basic/SourceManager.h"
14 #include "clang/Basic/Specifiers.h"
15 #include "clang/Lex/Lexer.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/ADT/Twine.h"
19 #include "llvm/Support/LineIterator.h"
20 #include "llvm/Support/MD5.h"
21 #include "llvm/Support/Path.h"
22
23 #include <functional>
24 #include <optional>
25 #include <sstream>
26 #include <string>
27
28 using namespace clang;
29
30 // Get a string representation of the parts of the signature that can be
31 // overloaded on.
GetSignature(const FunctionDecl * Target)32 static std::string GetSignature(const FunctionDecl *Target) {
33 if (!Target)
34 return "";
35 std::string Signature;
36
37 // When a flow sensitive bug happens in templated code we should not generate
38 // distinct hash value for every instantiation. Use the signature from the
39 // primary template.
40 if (const FunctionDecl *InstantiatedFrom =
41 Target->getTemplateInstantiationPattern())
42 Target = InstantiatedFrom;
43
44 if (!isa<CXXConstructorDecl>(Target) && !isa<CXXDestructorDecl>(Target) &&
45 !isa<CXXConversionDecl>(Target))
46 Signature.append(Target->getReturnType().getAsString()).append(" ");
47 Signature.append(Target->getQualifiedNameAsString()).append("(");
48
49 for (int i = 0, paramsCount = Target->getNumParams(); i < paramsCount; ++i) {
50 if (i)
51 Signature.append(", ");
52 Signature.append(Target->getParamDecl(i)->getType().getAsString());
53 }
54
55 if (Target->isVariadic())
56 Signature.append(", ...");
57 Signature.append(")");
58
59 const auto *TargetT =
60 llvm::dyn_cast_or_null<FunctionType>(Target->getType().getTypePtr());
61
62 if (!TargetT || !isa<CXXMethodDecl>(Target))
63 return Signature;
64
65 if (TargetT->isConst())
66 Signature.append(" const");
67 if (TargetT->isVolatile())
68 Signature.append(" volatile");
69 if (TargetT->isRestrict())
70 Signature.append(" restrict");
71
72 if (const auto *TargetPT =
73 dyn_cast_or_null<FunctionProtoType>(Target->getType().getTypePtr())) {
74 switch (TargetPT->getRefQualifier()) {
75 case RQ_LValue:
76 Signature.append(" &");
77 break;
78 case RQ_RValue:
79 Signature.append(" &&");
80 break;
81 default:
82 break;
83 }
84 }
85
86 return Signature;
87 }
88
GetEnclosingDeclContextSignature(const Decl * D)89 static std::string GetEnclosingDeclContextSignature(const Decl *D) {
90 if (!D)
91 return "";
92
93 if (const auto *ND = dyn_cast<NamedDecl>(D)) {
94 std::string DeclName;
95
96 switch (ND->getKind()) {
97 case Decl::Namespace:
98 case Decl::Record:
99 case Decl::CXXRecord:
100 case Decl::Enum:
101 DeclName = ND->getQualifiedNameAsString();
102 break;
103 case Decl::CXXConstructor:
104 case Decl::CXXDestructor:
105 case Decl::CXXConversion:
106 case Decl::CXXMethod:
107 case Decl::Function:
108 DeclName = GetSignature(dyn_cast_or_null<FunctionDecl>(ND));
109 break;
110 case Decl::ObjCMethod:
111 // ObjC Methods can not be overloaded, qualified name uniquely identifies
112 // the method.
113 DeclName = ND->getQualifiedNameAsString();
114 break;
115 default:
116 break;
117 }
118
119 return DeclName;
120 }
121
122 return "";
123 }
124
GetNthLineOfFile(std::optional<llvm::MemoryBufferRef> Buffer,int Line)125 static StringRef GetNthLineOfFile(std::optional<llvm::MemoryBufferRef> Buffer,
126 int Line) {
127 if (!Buffer)
128 return "";
129
130 llvm::line_iterator LI(*Buffer, false);
131 for (; !LI.is_at_eof() && LI.line_number() != Line; ++LI)
132 ;
133
134 return *LI;
135 }
136
NormalizeLine(const SourceManager & SM,const FullSourceLoc & L,const LangOptions & LangOpts)137 static std::string NormalizeLine(const SourceManager &SM, const FullSourceLoc &L,
138 const LangOptions &LangOpts) {
139 static StringRef Whitespaces = " \t\n";
140
141 StringRef Str = GetNthLineOfFile(SM.getBufferOrNone(L.getFileID(), L),
142 L.getExpansionLineNumber());
143 StringRef::size_type col = Str.find_first_not_of(Whitespaces);
144 if (col == StringRef::npos)
145 col = 1; // The line only contains whitespace.
146 else
147 col++;
148 SourceLocation StartOfLine =
149 SM.translateLineCol(SM.getFileID(L), L.getExpansionLineNumber(), col);
150 std::optional<llvm::MemoryBufferRef> Buffer =
151 SM.getBufferOrNone(SM.getFileID(StartOfLine), StartOfLine);
152 if (!Buffer)
153 return {};
154
155 const char *BufferPos = SM.getCharacterData(StartOfLine);
156
157 Token Token;
158 Lexer Lexer(SM.getLocForStartOfFile(SM.getFileID(StartOfLine)), LangOpts,
159 Buffer->getBufferStart(), BufferPos, Buffer->getBufferEnd());
160
161 size_t NextStart = 0;
162 std::ostringstream LineBuff;
163 while (!Lexer.LexFromRawLexer(Token) && NextStart < 2) {
164 if (Token.isAtStartOfLine() && NextStart++ > 0)
165 continue;
166 LineBuff << std::string(SM.getCharacterData(Token.getLocation()),
167 Token.getLength());
168 }
169
170 return LineBuff.str();
171 }
172
GetMD5HashOfContent(StringRef Content)173 static llvm::SmallString<32> GetMD5HashOfContent(StringRef Content) {
174 llvm::MD5 Hash;
175 llvm::MD5::MD5Result MD5Res;
176 SmallString<32> Res;
177
178 Hash.update(Content);
179 Hash.final(MD5Res);
180 llvm::MD5::stringifyResult(MD5Res, Res);
181
182 return Res;
183 }
184
getIssueString(const FullSourceLoc & IssueLoc,StringRef CheckerName,StringRef WarningMessage,const Decl * IssueDecl,const LangOptions & LangOpts)185 std::string clang::getIssueString(const FullSourceLoc &IssueLoc,
186 StringRef CheckerName,
187 StringRef WarningMessage,
188 const Decl *IssueDecl,
189 const LangOptions &LangOpts) {
190 static StringRef Delimiter = "$";
191
192 return (llvm::Twine(CheckerName) + Delimiter +
193 GetEnclosingDeclContextSignature(IssueDecl) + Delimiter +
194 Twine(IssueLoc.getExpansionColumnNumber()) + Delimiter +
195 NormalizeLine(IssueLoc.getManager(), IssueLoc, LangOpts) +
196 Delimiter + WarningMessage)
197 .str();
198 }
199
getIssueHash(const FullSourceLoc & IssueLoc,StringRef CheckerName,StringRef WarningMessage,const Decl * IssueDecl,const LangOptions & LangOpts)200 SmallString<32> clang::getIssueHash(const FullSourceLoc &IssueLoc,
201 StringRef CheckerName,
202 StringRef WarningMessage,
203 const Decl *IssueDecl,
204 const LangOptions &LangOpts) {
205
206 return GetMD5HashOfContent(getIssueString(
207 IssueLoc, CheckerName, WarningMessage, IssueDecl, LangOpts));
208 }
209