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      1 //===--- TextDiagnosticPrinter.cpp - Diagnostic Printer -------------------===//
      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 // This diagnostic client prints out their diagnostic messages.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "clang/Frontend/TextDiagnosticPrinter.h"
     15 #include "clang/Basic/DiagnosticOptions.h"
     16 #include "clang/Basic/FileManager.h"
     17 #include "clang/Basic/SourceManager.h"
     18 #include "clang/Frontend/TextDiagnostic.h"
     19 #include "clang/Lex/Lexer.h"
     20 #include "llvm/ADT/SmallString.h"
     21 #include "llvm/Support/ErrorHandling.h"
     22 #include "llvm/Support/MemoryBuffer.h"
     23 #include "llvm/Support/raw_ostream.h"
     24 #include <algorithm>
     25 using namespace clang;
     26 
     27 TextDiagnosticPrinter::TextDiagnosticPrinter(raw_ostream &os,
     28                                              DiagnosticOptions *diags,
     29                                              bool _OwnsOutputStream)
     30   : OS(os), DiagOpts(diags),
     31     OwnsOutputStream(_OwnsOutputStream) {
     32 }
     33 
     34 TextDiagnosticPrinter::~TextDiagnosticPrinter() {
     35   if (OwnsOutputStream)
     36     delete &OS;
     37 }
     38 
     39 void TextDiagnosticPrinter::BeginSourceFile(const LangOptions &LO,
     40                                             const Preprocessor *PP) {
     41   // Build the TextDiagnostic utility.
     42   TextDiag.reset(new TextDiagnostic(OS, LO, &*DiagOpts));
     43 }
     44 
     45 void TextDiagnosticPrinter::EndSourceFile() {
     46   TextDiag.reset(0);
     47 }
     48 
     49 /// \brief Print any diagnostic option information to a raw_ostream.
     50 ///
     51 /// This implements all of the logic for adding diagnostic options to a message
     52 /// (via OS). Each relevant option is comma separated and all are enclosed in
     53 /// the standard bracketing: " [...]".
     54 static void printDiagnosticOptions(raw_ostream &OS,
     55                                    DiagnosticsEngine::Level Level,
     56                                    const Diagnostic &Info,
     57                                    const DiagnosticOptions &DiagOpts) {
     58   bool Started = false;
     59   if (DiagOpts.ShowOptionNames) {
     60     // Handle special cases for non-warnings early.
     61     if (Info.getID() == diag::fatal_too_many_errors) {
     62       OS << " [-ferror-limit=]";
     63       return;
     64     }
     65 
     66     // The code below is somewhat fragile because we are essentially trying to
     67     // report to the user what happened by inferring what the diagnostic engine
     68     // did. Eventually it might make more sense to have the diagnostic engine
     69     // include some "why" information in the diagnostic.
     70 
     71     // If this is a warning which has been mapped to an error by the user (as
     72     // inferred by checking whether the default mapping is to an error) then
     73     // flag it as such. Note that diagnostics could also have been mapped by a
     74     // pragma, but we don't currently have a way to distinguish this.
     75     if (Level == DiagnosticsEngine::Error &&
     76         DiagnosticIDs::isBuiltinWarningOrExtension(Info.getID()) &&
     77         !DiagnosticIDs::isDefaultMappingAsError(Info.getID())) {
     78       OS << " [-Werror";
     79       Started = true;
     80     }
     81 
     82     StringRef Opt = DiagnosticIDs::getWarningOptionForDiag(Info.getID());
     83     if (!Opt.empty()) {
     84       OS << (Started ? "," : " [") << "-W" << Opt;
     85       Started = true;
     86     }
     87   }
     88 
     89   // If the user wants to see category information, include it too.
     90   if (DiagOpts.ShowCategories) {
     91     unsigned DiagCategory =
     92       DiagnosticIDs::getCategoryNumberForDiag(Info.getID());
     93     if (DiagCategory) {
     94       OS << (Started ? "," : " [");
     95       Started = true;
     96       if (DiagOpts.ShowCategories == 1)
     97         OS << DiagCategory;
     98       else {
     99         assert(DiagOpts.ShowCategories == 2 && "Invalid ShowCategories value");
    100         OS << DiagnosticIDs::getCategoryNameFromID(DiagCategory);
    101       }
    102     }
    103   }
    104   if (Started)
    105     OS << ']';
    106 }
    107 
    108 void TextDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
    109                                              const Diagnostic &Info) {
    110   // Default implementation (Warnings/errors count).
    111   DiagnosticConsumer::HandleDiagnostic(Level, Info);
    112 
    113   // Render the diagnostic message into a temporary buffer eagerly. We'll use
    114   // this later as we print out the diagnostic to the terminal.
    115   SmallString<100> OutStr;
    116   Info.FormatDiagnostic(OutStr);
    117 
    118   llvm::raw_svector_ostream DiagMessageStream(OutStr);
    119   printDiagnosticOptions(DiagMessageStream, Level, Info, *DiagOpts);
    120 
    121   // Keeps track of the starting position of the location
    122   // information (e.g., "foo.c:10:4:") that precedes the error
    123   // message. We use this information to determine how long the
    124   // file+line+column number prefix is.
    125   uint64_t StartOfLocationInfo = OS.tell();
    126 
    127   if (!Prefix.empty())
    128     OS << Prefix << ": ";
    129 
    130   // Use a dedicated, simpler path for diagnostics without a valid location.
    131   // This is important as if the location is missing, we may be emitting
    132   // diagnostics in a context that lacks language options, a source manager, or
    133   // other infrastructure necessary when emitting more rich diagnostics.
    134   if (!Info.getLocation().isValid()) {
    135     TextDiagnostic::printDiagnosticLevel(OS, Level, DiagOpts->ShowColors);
    136     TextDiagnostic::printDiagnosticMessage(OS, Level, DiagMessageStream.str(),
    137                                            OS.tell() - StartOfLocationInfo,
    138                                            DiagOpts->MessageLength,
    139                                            DiagOpts->ShowColors);
    140     OS.flush();
    141     return;
    142   }
    143 
    144   // Assert that the rest of our infrastructure is setup properly.
    145   assert(DiagOpts && "Unexpected diagnostic without options set");
    146   assert(Info.hasSourceManager() &&
    147          "Unexpected diagnostic with no source manager");
    148   assert(TextDiag && "Unexpected diagnostic outside source file processing");
    149 
    150   TextDiag->emitDiagnostic(Info.getLocation(), Level, DiagMessageStream.str(),
    151                            Info.getRanges(),
    152                            llvm::makeArrayRef(Info.getFixItHints(),
    153                                               Info.getNumFixItHints()),
    154                            &Info.getSourceManager());
    155 
    156   OS.flush();
    157 }
    158 
    159 DiagnosticConsumer *
    160 TextDiagnosticPrinter::clone(DiagnosticsEngine &Diags) const {
    161   return new TextDiagnosticPrinter(OS, &*DiagOpts, /*OwnsOutputStream=*/false);
    162 }
    163