Home | History | Annotate | Download | only in Frontend 
      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/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   unsigned CurrentIncludeDepth;
     23   bool HasProcessedPredefines;
     24   bool OwnsOutputFile;
     25   bool ShowAllHeaders;
     26   bool ShowDepth;
     27   bool MSStyle;
     28 
     29 public:
     30   HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
     31                          raw_ostream *OutputFile_, bool OwnsOutputFile_,
     32                          bool ShowDepth_, bool MSStyle_)
     33     : SM(PP->getSourceManager()), OutputFile(OutputFile_),
     34       CurrentIncludeDepth(0), HasProcessedPredefines(false),
     35       OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
     36       ShowDepth(ShowDepth_), MSStyle(MSStyle_) {}
     37 
     38   ~HeaderIncludesCallback() {
     39     if (OwnsOutputFile)
     40       delete OutputFile;
     41   }
     42 
     43   void FileChanged(SourceLocation Loc, FileChangeReason Reason,
     44                    SrcMgr::CharacteristicKind FileType,
     45                    FileID PrevFID) override;
     46 };
     47 }
     48 
     49 void clang::AttachHeaderIncludeGen(Preprocessor &PP, bool ShowAllHeaders,
     50                                    StringRef OutputPath, bool ShowDepth,
     51                                    bool MSStyle) {
     52   raw_ostream *OutputFile = MSStyle ? &llvm::outs() : &llvm::errs();
     53   bool OwnsOutputFile = false;
     54 
     55   // Open the output file, if used.
     56   if (!OutputPath.empty()) {
     57     std::string Error;
     58     llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
     59         OutputPath.str().c_str(), Error,
     60         llvm::sys::fs::F_Append | llvm::sys::fs::F_Text);
     61     if (!Error.empty()) {
     62       PP.getDiagnostics().Report(
     63         clang::diag::warn_fe_cc_print_header_failure) << Error;
     64       delete OS;
     65     } else {
     66       OS->SetUnbuffered();
     67       OS->SetUseAtomicWrites(true);
     68       OutputFile = OS;
     69       OwnsOutputFile = true;
     70     }
     71   }
     72 
     73   PP.addPPCallbacks(new HeaderIncludesCallback(&PP, ShowAllHeaders,
     74                                                OutputFile, OwnsOutputFile,
     75                                                ShowDepth, MSStyle));
     76 }
     77 
     78 void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
     79                                          FileChangeReason Reason,
     80                                        SrcMgr::CharacteristicKind NewFileType,
     81                                        FileID PrevFID) {
     82   // Unless we are exiting a #include, make sure to skip ahead to the line the
     83   // #include directive was at.
     84   PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
     85   if (UserLoc.isInvalid())
     86     return;
     87 
     88   // Adjust the current include depth.
     89   if (Reason == PPCallbacks::EnterFile) {
     90     ++CurrentIncludeDepth;
     91   } else if (Reason == PPCallbacks::ExitFile) {
     92     if (CurrentIncludeDepth)
     93       --CurrentIncludeDepth;
     94 
     95     // We track when we are done with the predefines by watching for the first
     96     // place where we drop back to a nesting depth of 1.
     97     if (CurrentIncludeDepth == 1 && !HasProcessedPredefines)
     98       HasProcessedPredefines = true;
     99 
    100     return;
    101   } else
    102     return;
    103 
    104   // Show the header if we are (a) past the predefines, or (b) showing all
    105   // headers and in the predefines at a depth past the initial file and command
    106   // line buffers.
    107   bool ShowHeader = (HasProcessedPredefines ||
    108                      (ShowAllHeaders && CurrentIncludeDepth > 2));
    109 
    110   // Dump the header include information we are past the predefines buffer or
    111   // are showing all headers.
    112   if (ShowHeader && Reason == PPCallbacks::EnterFile) {
    113     // Write to a temporary string to avoid unnecessary flushing on errs().
    114     SmallString<512> Filename(UserLoc.getFilename());
    115     if (!MSStyle)
    116       Lexer::Stringify(Filename);
    117 
    118     SmallString<256> Msg;
    119     if (MSStyle)
    120       Msg += "Note: including file:";
    121 
    122     if (ShowDepth) {
    123       // The main source file is at depth 1, so skip one dot.
    124       for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
    125         Msg += MSStyle ? ' ' : '.';
    126 
    127       if (!MSStyle)
    128         Msg += ' ';
    129     }
    130     Msg += Filename;
    131     Msg += '\n';
    132 
    133     OutputFile->write(Msg.data(), Msg.size());
    134   }
    135 }
    136