1 //===-- HeaderIncludeGen.cpp - Generate Header Includes -------------------===//
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/Frontend/DependencyOutputOptions.h"
10 #include "clang/Frontend/Utils.h"
11 #include "clang/Basic/SourceManager.h"
12 #include "clang/Frontend/FrontendDiagnostic.h"
13 #include "clang/Lex/Preprocessor.h"
14 #include "llvm/ADT/SmallString.h"
15 #include "llvm/Support/raw_ostream.h"
16 using namespace clang;
17
18 namespace {
19 class HeaderIncludesCallback : public PPCallbacks {
20 SourceManager &SM;
21 raw_ostream *OutputFile;
22 const DependencyOutputOptions &DepOpts;
23 unsigned CurrentIncludeDepth;
24 bool HasProcessedPredefines;
25 bool OwnsOutputFile;
26 bool ShowAllHeaders;
27 bool ShowDepth;
28 bool MSStyle;
29
30 public:
HeaderIncludesCallback(const Preprocessor * PP,bool ShowAllHeaders_,raw_ostream * OutputFile_,const DependencyOutputOptions & DepOpts,bool OwnsOutputFile_,bool ShowDepth_,bool MSStyle_)31 HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
32 raw_ostream *OutputFile_,
33 const DependencyOutputOptions &DepOpts,
34 bool OwnsOutputFile_, bool ShowDepth_, bool MSStyle_)
35 : SM(PP->getSourceManager()), OutputFile(OutputFile_), DepOpts(DepOpts),
36 CurrentIncludeDepth(0), HasProcessedPredefines(false),
37 OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
38 ShowDepth(ShowDepth_), MSStyle(MSStyle_) {}
39
~HeaderIncludesCallback()40 ~HeaderIncludesCallback() override {
41 if (OwnsOutputFile)
42 delete OutputFile;
43 }
44
45 void FileChanged(SourceLocation Loc, FileChangeReason Reason,
46 SrcMgr::CharacteristicKind FileType,
47 FileID PrevFID) override;
48
49 void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
50 SrcMgr::CharacteristicKind FileType) override;
51 };
52 }
53
PrintHeaderInfo(raw_ostream * OutputFile,StringRef Filename,bool ShowDepth,unsigned CurrentIncludeDepth,bool MSStyle)54 static void PrintHeaderInfo(raw_ostream *OutputFile, StringRef Filename,
55 bool ShowDepth, unsigned CurrentIncludeDepth,
56 bool MSStyle) {
57 // Write to a temporary string to avoid unnecessary flushing on errs().
58 SmallString<512> Pathname(Filename);
59 if (!MSStyle)
60 Lexer::Stringify(Pathname);
61
62 SmallString<256> Msg;
63 if (MSStyle)
64 Msg += "Note: including file:";
65
66 if (ShowDepth) {
67 // The main source file is at depth 1, so skip one dot.
68 for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
69 Msg += MSStyle ? ' ' : '.';
70
71 if (!MSStyle)
72 Msg += ' ';
73 }
74 Msg += Pathname;
75 Msg += '\n';
76
77 *OutputFile << Msg;
78 OutputFile->flush();
79 }
80
AttachHeaderIncludeGen(Preprocessor & PP,const DependencyOutputOptions & DepOpts,bool ShowAllHeaders,StringRef OutputPath,bool ShowDepth,bool MSStyle)81 void clang::AttachHeaderIncludeGen(Preprocessor &PP,
82 const DependencyOutputOptions &DepOpts,
83 bool ShowAllHeaders, StringRef OutputPath,
84 bool ShowDepth, bool MSStyle) {
85 raw_ostream *OutputFile = &llvm::errs();
86 bool OwnsOutputFile = false;
87
88 // Choose output stream, when printing in cl.exe /showIncludes style.
89 if (MSStyle) {
90 switch (DepOpts.ShowIncludesDest) {
91 default:
92 llvm_unreachable("Invalid destination for /showIncludes output!");
93 case ShowIncludesDestination::Stderr:
94 OutputFile = &llvm::errs();
95 break;
96 case ShowIncludesDestination::Stdout:
97 OutputFile = &llvm::outs();
98 break;
99 }
100 }
101
102 // Open the output file, if used.
103 if (!OutputPath.empty()) {
104 std::error_code EC;
105 llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
106 OutputPath.str(), EC,
107 llvm::sys::fs::OF_Append | llvm::sys::fs::OF_TextWithCRLF);
108 if (EC) {
109 PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure)
110 << EC.message();
111 delete OS;
112 } else {
113 OS->SetUnbuffered();
114 OutputFile = OS;
115 OwnsOutputFile = true;
116 }
117 }
118
119 // Print header info for extra headers, pretending they were discovered by
120 // the regular preprocessor. The primary use case is to support proper
121 // generation of Make / Ninja file dependencies for implicit includes, such
122 // as sanitizer blacklists. It's only important for cl.exe compatibility,
123 // the GNU way to generate rules is -M / -MM / -MD / -MMD.
124 for (const auto &Header : DepOpts.ExtraDeps)
125 PrintHeaderInfo(OutputFile, Header.first, ShowDepth, 2, MSStyle);
126 PP.addPPCallbacks(std::make_unique<HeaderIncludesCallback>(
127 &PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth,
128 MSStyle));
129 }
130
FileChanged(SourceLocation Loc,FileChangeReason Reason,SrcMgr::CharacteristicKind NewFileType,FileID PrevFID)131 void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
132 FileChangeReason Reason,
133 SrcMgr::CharacteristicKind NewFileType,
134 FileID PrevFID) {
135 // Unless we are exiting a #include, make sure to skip ahead to the line the
136 // #include directive was at.
137 PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
138 if (UserLoc.isInvalid())
139 return;
140
141 // Adjust the current include depth.
142 if (Reason == PPCallbacks::EnterFile) {
143 ++CurrentIncludeDepth;
144 } else if (Reason == PPCallbacks::ExitFile) {
145 if (CurrentIncludeDepth)
146 --CurrentIncludeDepth;
147
148 // We track when we are done with the predefines by watching for the first
149 // place where we drop back to a nesting depth of 1.
150 if (CurrentIncludeDepth == 1 && !HasProcessedPredefines) {
151 if (!DepOpts.ShowIncludesPretendHeader.empty()) {
152 PrintHeaderInfo(OutputFile, DepOpts.ShowIncludesPretendHeader,
153 ShowDepth, 2, MSStyle);
154 }
155 HasProcessedPredefines = true;
156 }
157
158 return;
159 } else
160 return;
161
162 // Show the header if we are (a) past the predefines, or (b) showing all
163 // headers and in the predefines at a depth past the initial file and command
164 // line buffers.
165 bool ShowHeader = (HasProcessedPredefines ||
166 (ShowAllHeaders && CurrentIncludeDepth > 2));
167 unsigned IncludeDepth = CurrentIncludeDepth;
168 if (!HasProcessedPredefines)
169 --IncludeDepth; // Ignore indent from <built-in>.
170 else if (!DepOpts.ShowIncludesPretendHeader.empty())
171 ++IncludeDepth; // Pretend inclusion by ShowIncludesPretendHeader.
172
173 if (!DepOpts.IncludeSystemHeaders && isSystem(NewFileType))
174 ShowHeader = false;
175
176 // Dump the header include information we are past the predefines buffer or
177 // are showing all headers and this isn't the magic implicit <command line>
178 // header.
179 // FIXME: Identify headers in a more robust way than comparing their name to
180 // "<command line>" and "<built-in>" in a bunch of places.
181 if (ShowHeader && Reason == PPCallbacks::EnterFile &&
182 UserLoc.getFilename() != StringRef("<command line>")) {
183 PrintHeaderInfo(OutputFile, UserLoc.getFilename(), ShowDepth, IncludeDepth,
184 MSStyle);
185 }
186 }
187
FileSkipped(const FileEntryRef & SkippedFile,const Token & FilenameTok,SrcMgr::CharacteristicKind FileType)188 void HeaderIncludesCallback::FileSkipped(const FileEntryRef &SkippedFile, const
189 Token &FilenameTok,
190 SrcMgr::CharacteristicKind FileType) {
191 if (!DepOpts.ShowSkippedHeaderIncludes)
192 return;
193
194 if (!DepOpts.IncludeSystemHeaders && isSystem(FileType))
195 return;
196
197 PrintHeaderInfo(OutputFile, SkippedFile.getName(), ShowDepth,
198 CurrentIncludeDepth + 1, MSStyle);
199 }
200