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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/FileManager.h"
     16 #include "clang/Basic/SourceManager.h"
     17 #include "clang/Frontend/DiagnosticOptions.h"
     18 #include "clang/Frontend/TextDiagnostic.h"
     19 #include "clang/Lex/Lexer.h"
     20 #include "llvm/Support/MemoryBuffer.h"
     21 #include "llvm/Support/raw_ostream.h"
     22 #include "llvm/Support/ErrorHandling.h"
     23 #include "llvm/ADT/SmallString.h"
     24 #include <algorithm>
     25 using namespace clang;
     26 
     27 TextDiagnosticPrinter::TextDiagnosticPrinter(raw_ostream &os,
     28                                              const DiagnosticOptions &diags,
     29                                              bool _OwnsOutputStream)
     30   : OS(os), LangOpts(0), DiagOpts(&diags), SM(0),
     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   LangOpts = &LO;
     42 }
     43 
     44 void TextDiagnosticPrinter::EndSourceFile() {
     45   LangOpts = 0;
     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     // If the diagnostic is an extension diagnostic and not enabled by default
     83     // then it must have been turned on with -pedantic.
     84     bool EnabledByDefault;
     85     if (DiagnosticIDs::isBuiltinExtensionDiag(Info.getID(),
     86                                               EnabledByDefault) &&
     87         !EnabledByDefault) {
     88       OS << (Started ? "," : " [") << "-pedantic";
     89       Started = true;
     90     }
     91 
     92     StringRef Opt = DiagnosticIDs::getWarningOptionForDiag(Info.getID());
     93     if (!Opt.empty()) {
     94       OS << (Started ? "," : " [") << "-W" << Opt;
     95       Started = true;
     96     }
     97   }
     98 
     99   // If the user wants to see category information, include it too.
    100   if (DiagOpts.ShowCategories) {
    101     unsigned DiagCategory =
    102       DiagnosticIDs::getCategoryNumberForDiag(Info.getID());
    103     if (DiagCategory) {
    104       OS << (Started ? "," : " [");
    105       Started = true;
    106       if (DiagOpts.ShowCategories == 1)
    107         OS << DiagCategory;
    108       else {
    109         assert(DiagOpts.ShowCategories == 2 && "Invalid ShowCategories value");
    110         OS << DiagnosticIDs::getCategoryNameFromID(DiagCategory);
    111       }
    112     }
    113   }
    114   if (Started)
    115     OS << ']';
    116 }
    117 
    118 void TextDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
    119                                              const Diagnostic &Info) {
    120   // Default implementation (Warnings/errors count).
    121   DiagnosticConsumer::HandleDiagnostic(Level, Info);
    122 
    123   // Render the diagnostic message into a temporary buffer eagerly. We'll use
    124   // this later as we print out the diagnostic to the terminal.
    125   SmallString<100> OutStr;
    126   Info.FormatDiagnostic(OutStr);
    127 
    128   llvm::raw_svector_ostream DiagMessageStream(OutStr);
    129   printDiagnosticOptions(DiagMessageStream, Level, Info, *DiagOpts);
    130 
    131   // Keeps track of the the starting position of the location
    132   // information (e.g., "foo.c:10:4:") that precedes the error
    133   // message. We use this information to determine how long the
    134   // file+line+column number prefix is.
    135   uint64_t StartOfLocationInfo = OS.tell();
    136 
    137   if (!Prefix.empty())
    138     OS << Prefix << ": ";
    139 
    140   // Use a dedicated, simpler path for diagnostics without a valid location.
    141   // This is important as if the location is missing, we may be emitting
    142   // diagnostics in a context that lacks language options, a source manager, or
    143   // other infrastructure necessary when emitting more rich diagnostics.
    144   if (!Info.getLocation().isValid()) {
    145     TextDiagnostic::printDiagnosticLevel(OS, Level, DiagOpts->ShowColors);
    146     TextDiagnostic::printDiagnosticMessage(OS, Level, DiagMessageStream.str(),
    147                                            OS.tell() - StartOfLocationInfo,
    148                                            DiagOpts->MessageLength,
    149                                            DiagOpts->ShowColors);
    150     OS.flush();
    151     return;
    152   }
    153 
    154   // Assert that the rest of our infrastructure is setup properly.
    155   assert(LangOpts && "Unexpected diagnostic outside source file processing");
    156   assert(DiagOpts && "Unexpected diagnostic without options set");
    157   assert(Info.hasSourceManager() &&
    158          "Unexpected diagnostic with no source manager");
    159 
    160   // Rebuild the TextDiagnostic utility if missing or the source manager has
    161   // changed.
    162   if (!TextDiag || SM != &Info.getSourceManager()) {
    163     SM = &Info.getSourceManager();
    164     TextDiag.reset(new TextDiagnostic(OS, *SM, *LangOpts, *DiagOpts));
    165   }
    166 
    167   TextDiag->emitDiagnostic(Info.getLocation(), Level, DiagMessageStream.str(),
    168                            Info.getRanges(),
    169                            llvm::makeArrayRef(Info.getFixItHints(),
    170                                               Info.getNumFixItHints()));
    171 
    172   OS.flush();
    173 }
    174 
    175 DiagnosticConsumer *
    176 TextDiagnosticPrinter::clone(DiagnosticsEngine &Diags) const {
    177   return new TextDiagnosticPrinter(OS, *DiagOpts, /*OwnsOutputStream=*/false);
    178 }
    179