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: 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 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 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 79 void clang::AttachHeaderIncludeGen(Preprocessor &PP, 80 const DependencyOutputOptions &DepOpts, 81 bool ShowAllHeaders, StringRef OutputPath, 82 bool ShowDepth, bool MSStyle) { 83 raw_ostream *OutputFile = MSStyle ? &llvm::outs() : &llvm::errs(); 84 bool OwnsOutputFile = false; 85 86 // Open the output file, if used. 87 if (!OutputPath.empty()) { 88 std::error_code EC; 89 llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream( 90 OutputPath.str(), EC, llvm::sys::fs::F_Append | llvm::sys::fs::F_Text); 91 if (EC) { 92 PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure) 93 << EC.message(); 94 delete OS; 95 } else { 96 OS->SetUnbuffered(); 97 OutputFile = OS; 98 OwnsOutputFile = true; 99 } 100 } 101 102 // Print header info for extra headers, pretending they were discovered by 103 // the regular preprocessor. The primary use case is to support proper 104 // generation of Make / Ninja file dependencies for implicit includes, such 105 // as sanitizer blacklists. It's only important for cl.exe compatibility, 106 // the GNU way to generate rules is -M / -MM / -MD / -MMD. 107 for (const auto &Header : DepOpts.ExtraDeps) 108 PrintHeaderInfo(OutputFile, Header, ShowDepth, 2, MSStyle); 109 PP.addPPCallbacks(llvm::make_unique<HeaderIncludesCallback>( 110 &PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth, 111 MSStyle)); 112 } 113 114 void HeaderIncludesCallback::FileChanged(SourceLocation Loc, 115 FileChangeReason Reason, 116 SrcMgr::CharacteristicKind NewFileType, 117 FileID PrevFID) { 118 // Unless we are exiting a #include, make sure to skip ahead to the line the 119 // #include directive was at. 120 PresumedLoc UserLoc = SM.getPresumedLoc(Loc); 121 if (UserLoc.isInvalid()) 122 return; 123 124 // Adjust the current include depth. 125 if (Reason == PPCallbacks::EnterFile) { 126 ++CurrentIncludeDepth; 127 } else if (Reason == PPCallbacks::ExitFile) { 128 if (CurrentIncludeDepth) 129 --CurrentIncludeDepth; 130 131 // We track when we are done with the predefines by watching for the first 132 // place where we drop back to a nesting depth of 1. 133 if (CurrentIncludeDepth == 1 && !HasProcessedPredefines) { 134 if (!DepOpts.ShowIncludesPretendHeader.empty()) { 135 PrintHeaderInfo(OutputFile, DepOpts.ShowIncludesPretendHeader, 136 ShowDepth, 2, MSStyle); 137 } 138 HasProcessedPredefines = true; 139 } 140 141 return; 142 } else 143 return; 144 145 // Show the header if we are (a) past the predefines, or (b) showing all 146 // headers and in the predefines at a depth past the initial file and command 147 // line buffers. 148 bool ShowHeader = (HasProcessedPredefines || 149 (ShowAllHeaders && CurrentIncludeDepth > 2)); 150 unsigned IncludeDepth = CurrentIncludeDepth; 151 if (!HasProcessedPredefines) 152 --IncludeDepth; // Ignore indent from <built-in>. 153 else if (!DepOpts.ShowIncludesPretendHeader.empty()) 154 ++IncludeDepth; // Pretend inclusion by ShowIncludesPretendHeader. 155 156 // Dump the header include information we are past the predefines buffer or 157 // are showing all headers and this isn't the magic implicit <command line> 158 // header. 159 // FIXME: Identify headers in a more robust way than comparing their name to 160 // "<command line>" and "<built-in>" in a bunch of places. 161 if (ShowHeader && Reason == PPCallbacks::EnterFile && 162 UserLoc.getFilename() != StringRef("<command line>")) { 163 PrintHeaderInfo(OutputFile, UserLoc.getFilename(), ShowDepth, IncludeDepth, 164 MSStyle); 165 } 166 } 167