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