1 //===--- HeaderIncludes.cpp - Generate Header Includes --------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "clang/Frontend/DependencyOutputOptions.h"
11 #include "clang/Frontend/Utils.h"
12 #include "clang/Basic/SourceManager.h"
13 #include "clang/Frontend/FrontendDiagnostic.h"
14 #include "clang/Lex/Preprocessor.h"
15 #include "llvm/ADT/SmallString.h"
16 #include "llvm/Support/raw_ostream.h"
17 using namespace clang;
18
19 namespace {
20 class HeaderIncludesCallback : public PPCallbacks {
21 SourceManager &SM;
22 raw_ostream *OutputFile;
23 const DependencyOutputOptions &DepOpts;
24 unsigned CurrentIncludeDepth;
25 bool HasProcessedPredefines;
26 bool OwnsOutputFile;
27 bool ShowAllHeaders;
28 bool ShowDepth;
29 bool MSStyle;
30
31 public:
HeaderIncludesCallback(const Preprocessor * PP,bool ShowAllHeaders_,raw_ostream * OutputFile_,const DependencyOutputOptions & DepOpts,bool OwnsOutputFile_,bool ShowDepth_,bool MSStyle_)32 HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
33 raw_ostream *OutputFile_,
34 const DependencyOutputOptions &DepOpts,
35 bool OwnsOutputFile_, bool ShowDepth_, bool MSStyle_)
36 : SM(PP->getSourceManager()), OutputFile(OutputFile_), DepOpts(DepOpts),
37 CurrentIncludeDepth(0), HasProcessedPredefines(false),
38 OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
39 ShowDepth(ShowDepth_), MSStyle(MSStyle_) {}
40
~HeaderIncludesCallback()41 ~HeaderIncludesCallback() override {
42 if (OwnsOutputFile)
43 delete OutputFile;
44 }
45
46 void FileChanged(SourceLocation Loc, FileChangeReason Reason,
47 SrcMgr::CharacteristicKind FileType,
48 FileID PrevFID) override;
49 };
50 }
51
PrintHeaderInfo(raw_ostream * OutputFile,StringRef Filename,bool ShowDepth,unsigned CurrentIncludeDepth,bool MSStyle)52 static void PrintHeaderInfo(raw_ostream *OutputFile, StringRef Filename,
53 bool ShowDepth, unsigned CurrentIncludeDepth,
54 bool MSStyle) {
55 // Write to a temporary string to avoid unnecessary flushing on errs().
56 SmallString<512> Pathname(Filename);
57 if (!MSStyle)
58 Lexer::Stringify(Pathname);
59
60 SmallString<256> Msg;
61 if (MSStyle)
62 Msg += "Note: including file:";
63
64 if (ShowDepth) {
65 // The main source file is at depth 1, so skip one dot.
66 for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
67 Msg += MSStyle ? ' ' : '.';
68
69 if (!MSStyle)
70 Msg += ' ';
71 }
72 Msg += Pathname;
73 Msg += '\n';
74
75 *OutputFile << Msg;
76 OutputFile->flush();
77 }
78
AttachHeaderIncludeGen(Preprocessor & PP,const DependencyOutputOptions & DepOpts,bool ShowAllHeaders,StringRef OutputPath,bool ShowDepth,bool MSStyle)79 void clang::AttachHeaderIncludeGen(Preprocessor &PP,
80 const DependencyOutputOptions &DepOpts,
81 bool ShowAllHeaders, StringRef OutputPath,
82 bool ShowDepth, bool MSStyle) {
83 raw_ostream *OutputFile = &llvm::errs();
84 bool OwnsOutputFile = false;
85
86 // Choose output stream, when printing in cl.exe /showIncludes style.
87 if (MSStyle) {
88 switch (DepOpts.ShowIncludesDest) {
89 default:
90 llvm_unreachable("Invalid destination for /showIncludes output!");
91 case ShowIncludesDestination::Stderr:
92 OutputFile = &llvm::errs();
93 break;
94 case ShowIncludesDestination::Stdout:
95 OutputFile = &llvm::outs();
96 break;
97 }
98 }
99
100 // Open the output file, if used.
101 if (!OutputPath.empty()) {
102 std::error_code EC;
103 llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
104 OutputPath.str(), EC, llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
105 if (EC) {
106 PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure)
107 << EC.message();
108 delete OS;
109 } else {
110 OS->SetUnbuffered();
111 OutputFile = OS;
112 OwnsOutputFile = true;
113 }
114 }
115
116 // Print header info for extra headers, pretending they were discovered by
117 // the regular preprocessor. The primary use case is to support proper
118 // generation of Make / Ninja file dependencies for implicit includes, such
119 // as sanitizer blacklists. It's only important for cl.exe compatibility,
120 // the GNU way to generate rules is -M / -MM / -MD / -MMD.
121 for (const auto &Header : DepOpts.ExtraDeps)
122 PrintHeaderInfo(OutputFile, Header, ShowDepth, 2, MSStyle);
123 PP.addPPCallbacks(llvm::make_unique<HeaderIncludesCallback>(
124 &PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth,
125 MSStyle));
126 }
127
FileChanged(SourceLocation Loc,FileChangeReason Reason,SrcMgr::CharacteristicKind NewFileType,FileID PrevFID)128 void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
129 FileChangeReason Reason,
130 SrcMgr::CharacteristicKind NewFileType,
131 FileID PrevFID) {
132 // Unless we are exiting a #include, make sure to skip ahead to the line the
133 // #include directive was at.
134 PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
135 if (UserLoc.isInvalid())
136 return;
137
138 // Adjust the current include depth.
139 if (Reason == PPCallbacks::EnterFile) {
140 ++CurrentIncludeDepth;
141 } else if (Reason == PPCallbacks::ExitFile) {
142 if (CurrentIncludeDepth)
143 --CurrentIncludeDepth;
144
145 // We track when we are done with the predefines by watching for the first
146 // place where we drop back to a nesting depth of 1.
147 if (CurrentIncludeDepth == 1 && !HasProcessedPredefines) {
148 if (!DepOpts.ShowIncludesPretendHeader.empty()) {
149 PrintHeaderInfo(OutputFile, DepOpts.ShowIncludesPretendHeader,
150 ShowDepth, 2, MSStyle);
151 }
152 HasProcessedPredefines = true;
153 }
154
155 return;
156 } else
157 return;
158
159 // Show the header if we are (a) past the predefines, or (b) showing all
160 // headers and in the predefines at a depth past the initial file and command
161 // line buffers.
162 bool ShowHeader = (HasProcessedPredefines ||
163 (ShowAllHeaders && CurrentIncludeDepth > 2));
164 unsigned IncludeDepth = CurrentIncludeDepth;
165 if (!HasProcessedPredefines)
166 --IncludeDepth; // Ignore indent from <built-in>.
167 else if (!DepOpts.ShowIncludesPretendHeader.empty())
168 ++IncludeDepth; // Pretend inclusion by ShowIncludesPretendHeader.
169
170 // Dump the header include information we are past the predefines buffer or
171 // are showing all headers and this isn't the magic implicit <command line>
172 // header.
173 // FIXME: Identify headers in a more robust way than comparing their name to
174 // "<command line>" and "<built-in>" in a bunch of places.
175 if (ShowHeader && Reason == PPCallbacks::EnterFile &&
176 UserLoc.getFilename() != StringRef("<command line>")) {
177 PrintHeaderInfo(OutputFile, UserLoc.getFilename(), ShowDepth, IncludeDepth,
178 MSStyle);
179 }
180 }
181