Warnings.cpp revision 588e83bf3e998d79d3acc7c7179ca466787f72cc 
1//===--- Warnings.cpp - C-Language Front-end ------------------------------===//
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// Command line warning options handler.
11//
12//===----------------------------------------------------------------------===//
13//
14// This file is responsible for handling all warning options. This includes
15// a number of -Wfoo options and their variants, which are driven by TableGen-
16// generated data, and the special cases -pedantic, -pedantic-errors, -w,
17// -Werror and -Wfatal-errors.
18//
19// Each warning option controls any number of actual warnings.
20// Given a warning option 'foo', the following are valid:
21//    -Wfoo, -Wno-foo, -Werror=foo, -Wfatal-errors=foo
22//
23#include "clang/Frontend/Utils.h"
24#include "clang/Basic/Diagnostic.h"
25#include "clang/Sema/SemaDiagnostic.h"
26#include "clang/Lex/LexDiagnostic.h"
27#include "clang/Frontend/DiagnosticOptions.h"
28#include "clang/Frontend/FrontendDiagnostic.h"
29#include <cstring>
30#include <utility>
31#include <algorithm>
32using namespace clang;
33
34// EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning
35// opts
36static void EmitUnknownDiagWarning(DiagnosticsEngine &Diags,
37                                  StringRef Prefix, StringRef Opt,
38                                  bool isPositive) {
39  StringRef Suggestion = DiagnosticIDs::getNearestWarningOption(Opt);
40  if (!Suggestion.empty())
41    Diags.Report(isPositive? diag::warn_unknown_warning_option_suggest :
42                             diag::warn_unknown_negative_warning_option_suggest)
43      << (Prefix.str() += Opt) << (Prefix.str() += Suggestion);
44  else
45    Diags.Report(isPositive? diag::warn_unknown_warning_option :
46                             diag::warn_unknown_negative_warning_option)
47      << (Prefix.str() += Opt);
48}
49
50void clang::ProcessWarningOptions(DiagnosticsEngine &Diags,
51                                  const DiagnosticOptions &Opts) {
52  Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
53  Diags.setIgnoreAllWarnings(Opts.IgnoreWarnings);
54  Diags.setShowOverloads(
55    static_cast<DiagnosticsEngine::OverloadsShown>(Opts.ShowOverloads));
56
57  // Handle -ferror-limit
58  if (Opts.ErrorLimit)
59    Diags.setErrorLimit(Opts.ErrorLimit);
60  if (Opts.TemplateBacktraceLimit)
61    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
62  if (Opts.ConstexprBacktraceLimit)
63    Diags.setConstexprBacktraceLimit(Opts.ConstexprBacktraceLimit);
64
65  // If -pedantic or -pedantic-errors was specified, then we want to map all
66  // extension diagnostics onto WARNING or ERROR unless the user has futz'd
67  // around with them explicitly.
68  if (Opts.PedanticErrors)
69    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Error);
70  else if (Opts.Pedantic)
71    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Warn);
72  else
73    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Ignore);
74
75  llvm::SmallVector<diag::kind, 10> _Diags;
76  const llvm::IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs =
77    Diags.getDiagnosticIDs();
78  // We parse the warning options twice.  The first pass sets diagnostic state,
79  // while the second pass reports warnings/errors.  This has the effect that
80  // we follow the more canonical "last option wins" paradigm when there are
81  // conflicting options.
82  for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) {
83    bool SetDiagnostic = (Report == 0);
84    for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
85      StringRef Opt = Opts.Warnings[i];
86
87      // Treat -Wformat=0 as an alias for -Wno-format.
88      if (Opt == "format=0")
89        Opt = "no-format";
90
91      // Check to see if this warning starts with "no-", if so, this is a
92      // negative form of the option.
93      bool isPositive = true;
94      if (Opt.startswith("no-")) {
95        isPositive = false;
96        Opt = Opt.substr(3);
97      }
98
99      // Figure out how this option affects the warning.  If -Wfoo, map the
100      // diagnostic to a warning, if -Wno-foo, map it to ignore.
101      diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
102
103      // -Wsystem-headers is a special case, not driven by the option table.  It
104      // cannot be controlled with -Werror.
105      if (Opt == "system-headers") {
106        if (SetDiagnostic)
107          Diags.setSuppressSystemWarnings(!isPositive);
108        continue;
109      }
110
111      // -Weverything is a special case as well.  It implicitly enables all
112      // warnings, including ones not explicitly in a warning group.
113      if (Opt == "everything") {
114        if (SetDiagnostic) {
115          if (isPositive) {
116            Diags.setEnableAllWarnings(true);
117          } else {
118            Diags.setEnableAllWarnings(false);
119            Diags.setMappingToAllDiagnostics(diag::MAP_IGNORE);
120          }
121        }
122        continue;
123      }
124
125      // -Werror/-Wno-error is a special case, not controlled by the option
126      // table. It also has the "specifier" form of -Werror=foo and -Werror-foo.
127      if (Opt.startswith("error")) {
128        StringRef Specifier;
129        if (Opt.size() > 5) {  // Specifier must be present.
130          if ((Opt[5] != '=' && Opt[5] != '-') || Opt.size() == 6) {
131            if (Report)
132              Diags.Report(diag::warn_unknown_warning_specifier)
133                << "-Werror" << ("-W" + Opt.str());
134            continue;
135          }
136          Specifier = Opt.substr(6);
137        }
138
139        if (Specifier.empty()) {
140          if (SetDiagnostic)
141            Diags.setWarningsAsErrors(isPositive);
142          continue;
143        }
144
145        if (SetDiagnostic) {
146          // Set the warning as error flag for this specifier.
147          Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
148        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
149          EmitUnknownDiagWarning(Diags, "-Werror=", Specifier, isPositive);
150        }
151        continue;
152      }
153
154      // -Wfatal-errors is yet another special case.
155      if (Opt.startswith("fatal-errors")) {
156        StringRef Specifier;
157        if (Opt.size() != 12) {
158          if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
159            if (Report)
160              Diags.Report(diag::warn_unknown_warning_specifier)
161                << "-Wfatal-errors" << ("-W" + Opt.str());
162            continue;
163          }
164          Specifier = Opt.substr(13);
165        }
166
167        if (Specifier.empty()) {
168          if (SetDiagnostic)
169            Diags.setErrorsAsFatal(isPositive);
170          continue;
171        }
172
173        if (SetDiagnostic) {
174          // Set the error as fatal flag for this specifier.
175          Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
176        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
177          EmitUnknownDiagWarning(Diags, "-Wfatal-errors=", Specifier,
178                                 isPositive);
179        }
180        continue;
181      }
182
183      if (Report) {
184        if (DiagIDs->getDiagnosticsInGroup(Opt, _Diags))
185          EmitUnknownDiagWarning(Diags, "-W", Opt, isPositive);
186      } else {
187        Diags.setDiagnosticGroupMapping(Opt, Mapping);
188      }
189    }
190  }
191}
192