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: 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 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 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 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 ignorelists. 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 } 130 131 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 } 187 188 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