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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();
     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 ? "," : " [")
     85          << (Level == DiagnosticsEngine::Remark ? "-R" : "-W") << Opt;
     86       StringRef OptValue = Info.getDiags()->getFlagValue();
     87       if (!OptValue.empty())
     88         OS << "=" << OptValue;
     89       Started = true;
     90     }
     91   }
     92 
     93   // If the user wants to see category information, include it too.
     94   if (DiagOpts.ShowCategories) {
     95     unsigned DiagCategory =
     96       DiagnosticIDs::getCategoryNumberForDiag(Info.getID());
     97     if (DiagCategory) {
     98       OS << (Started ? "," : " [");
     99       Started = true;
    100       if (DiagOpts.ShowCategories == 1)
    101         OS << DiagCategory;
    102       else {
    103         assert(DiagOpts.ShowCategories == 2 && "Invalid ShowCategories value");
    104         OS << DiagnosticIDs::getCategoryNameFromID(DiagCategory);
    105       }
    106     }
    107   }
    108   if (Started)
    109     OS << ']';
    110 }
    111 
    112 void TextDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
    113                                              const Diagnostic &Info) {
    114   // Default implementation (Warnings/errors count).
    115   DiagnosticConsumer::HandleDiagnostic(Level, Info);
    116 
    117   // Render the diagnostic message into a temporary buffer eagerly. We'll use
    118   // this later as we print out the diagnostic to the terminal.
    119   SmallString<100> OutStr;
    120   Info.FormatDiagnostic(OutStr);
    121 
    122   llvm::raw_svector_ostream DiagMessageStream(OutStr);
    123   printDiagnosticOptions(DiagMessageStream, Level, Info, *DiagOpts);
    124 
    125   // Keeps track of the starting position of the location
    126   // information (e.g., "foo.c:10:4:") that precedes the error
    127   // message. We use this information to determine how long the
    128   // file+line+column number prefix is.
    129   uint64_t StartOfLocationInfo = OS.tell();
    130 
    131   if (!Prefix.empty())
    132     OS << Prefix << ": ";
    133 
    134   // Use a dedicated, simpler path for diagnostics without a valid location.
    135   // This is important as if the location is missing, we may be emitting
    136   // diagnostics in a context that lacks language options, a source manager, or
    137   // other infrastructure necessary when emitting more rich diagnostics.
    138   if (!Info.getLocation().isValid()) {
    139     TextDiagnostic::printDiagnosticLevel(OS, Level, DiagOpts->ShowColors,
    140                                          DiagOpts->CLFallbackMode);
    141     TextDiagnostic::printDiagnosticMessage(OS, Level, DiagMessageStream.str(),
    142                                            OS.tell() - StartOfLocationInfo,
    143                                            DiagOpts->MessageLength,
    144                                            DiagOpts->ShowColors);
    145     OS.flush();
    146     return;
    147   }
    148 
    149   // Assert that the rest of our infrastructure is setup properly.
    150   assert(DiagOpts && "Unexpected diagnostic without options set");
    151   assert(Info.hasSourceManager() &&
    152          "Unexpected diagnostic with no source manager");
    153   assert(TextDiag && "Unexpected diagnostic outside source file processing");
    154 
    155   TextDiag->emitDiagnostic(Info.getLocation(), Level, DiagMessageStream.str(),
    156                            Info.getRanges(),
    157                            Info.getFixItHints(),
    158                            &Info.getSourceManager());
    159 
    160   OS.flush();
    161 }
    162