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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 the diagnostic name to a raw_ostream.
     50 ///
     51 /// This prints the diagnostic name to a raw_ostream if it has one. It formats
     52 /// the name according to the expected diagnostic message formatting:
     53 ///   " [diagnostic_name_here]"
     54 static void printDiagnosticName(raw_ostream &OS, const Diagnostic &Info) {
     55   if (!DiagnosticIDs::isBuiltinNote(Info.getID()))
     56     OS << " [" << DiagnosticIDs::getName(Info.getID()) << "]";
     57 }
     58 
     59 /// \brief Print any diagnostic option information to a raw_ostream.
     60 ///
     61 /// This implements all of the logic for adding diagnostic options to a message
     62 /// (via OS). Each relevant option is comma separated and all are enclosed in
     63 /// the standard bracketing: " [...]".
     64 static void printDiagnosticOptions(raw_ostream &OS,
     65                                    DiagnosticsEngine::Level Level,
     66                                    const Diagnostic &Info,
     67                                    const DiagnosticOptions &DiagOpts) {
     68   bool Started = false;
     69   if (DiagOpts.ShowOptionNames) {
     70     // Handle special cases for non-warnings early.
     71     if (Info.getID() == diag::fatal_too_many_errors) {
     72       OS << " [-ferror-limit=]";
     73       return;
     74     }
     75 
     76     // The code below is somewhat fragile because we are essentially trying to
     77     // report to the user what happened by inferring what the diagnostic engine
     78     // did. Eventually it might make more sense to have the diagnostic engine
     79     // include some "why" information in the diagnostic.
     80 
     81     // If this is a warning which has been mapped to an error by the user (as
     82     // inferred by checking whether the default mapping is to an error) then
     83     // flag it as such. Note that diagnostics could also have been mapped by a
     84     // pragma, but we don't currently have a way to distinguish this.
     85     if (Level == DiagnosticsEngine::Error &&
     86         DiagnosticIDs::isBuiltinWarningOrExtension(Info.getID()) &&
     87         !DiagnosticIDs::isDefaultMappingAsError(Info.getID())) {
     88       OS << " [-Werror";
     89       Started = true;
     90     }
     91 
     92     // If the diagnostic is an extension diagnostic and not enabled by default
     93     // then it must have been turned on with -pedantic.
     94     bool EnabledByDefault;
     95     if (DiagnosticIDs::isBuiltinExtensionDiag(Info.getID(),
     96                                               EnabledByDefault) &&
     97         !EnabledByDefault) {
     98       OS << (Started ? "," : " [") << "-pedantic";
     99       Started = true;
    100     }
    101 
    102     StringRef Opt = DiagnosticIDs::getWarningOptionForDiag(Info.getID());
    103     if (!Opt.empty()) {
    104       OS << (Started ? "," : " [") << "-W" << Opt;
    105       Started = true;
    106     }
    107   }
    108 
    109   // If the user wants to see category information, include it too.
    110   if (DiagOpts.ShowCategories) {
    111     unsigned DiagCategory =
    112       DiagnosticIDs::getCategoryNumberForDiag(Info.getID());
    113     if (DiagCategory) {
    114       OS << (Started ? "," : " [");
    115       Started = true;
    116       if (DiagOpts.ShowCategories == 1)
    117         OS << DiagCategory;
    118       else {
    119         assert(DiagOpts.ShowCategories == 2 && "Invalid ShowCategories value");
    120         OS << DiagnosticIDs::getCategoryNameFromID(DiagCategory);
    121       }
    122     }
    123   }
    124   if (Started)
    125     OS << ']';
    126 }
    127 
    128 void TextDiagnosticPrinter::HandleDiagnostic(DiagnosticsEngine::Level Level,
    129                                              const Diagnostic &Info) {
    130   // Default implementation (Warnings/errors count).
    131   DiagnosticConsumer::HandleDiagnostic(Level, Info);
    132 
    133   // Render the diagnostic message into a temporary buffer eagerly. We'll use
    134   // this later as we print out the diagnostic to the terminal.
    135   llvm::SmallString<100> OutStr;
    136   Info.FormatDiagnostic(OutStr);
    137 
    138   llvm::raw_svector_ostream DiagMessageStream(OutStr);
    139   if (DiagOpts->ShowNames)
    140     printDiagnosticName(DiagMessageStream, Info);
    141   printDiagnosticOptions(DiagMessageStream, Level, Info, *DiagOpts);
    142 
    143   // Keeps track of the the starting position of the location
    144   // information (e.g., "foo.c:10:4:") that precedes the error
    145   // message. We use this information to determine how long the
    146   // file+line+column number prefix is.
    147   uint64_t StartOfLocationInfo = OS.tell();
    148 
    149   if (!Prefix.empty())
    150     OS << Prefix << ": ";
    151 
    152   // Use a dedicated, simpler path for diagnostics without a valid location.
    153   // This is important as if the location is missing, we may be emitting
    154   // diagnostics in a context that lacks language options, a source manager, or
    155   // other infrastructure necessary when emitting more rich diagnostics.
    156   if (!Info.getLocation().isValid()) {
    157     TextDiagnostic::printDiagnosticLevel(OS, Level, DiagOpts->ShowColors);
    158     TextDiagnostic::printDiagnosticMessage(OS, Level, DiagMessageStream.str(),
    159                                            OS.tell() - StartOfLocationInfo,
    160                                            DiagOpts->MessageLength,
    161                                            DiagOpts->ShowColors);
    162     OS.flush();
    163     return;
    164   }
    165 
    166   // Assert that the rest of our infrastructure is setup properly.
    167   assert(LangOpts && "Unexpected diagnostic outside source file processing");
    168   assert(DiagOpts && "Unexpected diagnostic without options set");
    169   assert(Info.hasSourceManager() &&
    170          "Unexpected diagnostic with no source manager");
    171 
    172   // Rebuild the TextDiagnostic utility if missing or the source manager has
    173   // changed.
    174   if (!TextDiag || SM != &Info.getSourceManager()) {
    175     SM = &Info.getSourceManager();
    176     TextDiag.reset(new TextDiagnostic(OS, *SM, *LangOpts, *DiagOpts));
    177   }
    178 
    179   TextDiag->emitDiagnostic(Info.getLocation(), Level, DiagMessageStream.str(),
    180                            Info.getRanges(),
    181                            llvm::makeArrayRef(Info.getFixItHints(),
    182                                               Info.getNumFixItHints()));
    183 
    184   OS.flush();
    185 }
    186 
    187 DiagnosticConsumer *
    188 TextDiagnosticPrinter::clone(DiagnosticsEngine &Diags) const {
    189   return new TextDiagnosticPrinter(OS, *DiagOpts, /*OwnsOutputStream=*/false);
    190 }
    191