Warnings.cpp revision dc7b641574a733624489bd87fc7061771edf2113 
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/Basic/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(Opts.getShowOverloads());
55
56  Diags.setElideType(Opts.ElideType);
57  Diags.setPrintTemplateTree(Opts.ShowTemplateTree);
58  Diags.setShowColors(Opts.ShowColors);
59
60  // Handle -ferror-limit
61  if (Opts.ErrorLimit)
62    Diags.setErrorLimit(Opts.ErrorLimit);
63  if (Opts.TemplateBacktraceLimit)
64    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
65  if (Opts.ConstexprBacktraceLimit)
66    Diags.setConstexprBacktraceLimit(Opts.ConstexprBacktraceLimit);
67
68  // If -pedantic or -pedantic-errors was specified, then we want to map all
69  // extension diagnostics onto WARNING or ERROR unless the user has futz'd
70  // around with them explicitly.
71  if (Opts.PedanticErrors)
72    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Error);
73  else if (Opts.Pedantic)
74    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Warn);
75  else
76    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Ignore);
77
78  llvm::SmallVector<diag::kind, 10> _Diags;
79  const IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs =
80    Diags.getDiagnosticIDs();
81  // We parse the warning options twice.  The first pass sets diagnostic state,
82  // while the second pass reports warnings/errors.  This has the effect that
83  // we follow the more canonical "last option wins" paradigm when there are
84  // conflicting options.
85  for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) {
86    bool SetDiagnostic = (Report == 0);
87    for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
88      StringRef Opt = Opts.Warnings[i];
89      StringRef OrigOpt = Opts.Warnings[i];
90
91      // Treat -Wformat=0 as an alias for -Wno-format.
92      if (Opt == "format=0")
93        Opt = "no-format";
94
95      // Check to see if this warning starts with "no-", if so, this is a
96      // negative form of the option.
97      bool isPositive = true;
98      if (Opt.startswith("no-")) {
99        isPositive = false;
100        Opt = Opt.substr(3);
101      }
102
103      // Figure out how this option affects the warning.  If -Wfoo, map the
104      // diagnostic to a warning, if -Wno-foo, map it to ignore.
105      diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
106
107      // -Wsystem-headers is a special case, not driven by the option table.  It
108      // cannot be controlled with -Werror.
109      if (Opt == "system-headers") {
110        if (SetDiagnostic)
111          Diags.setSuppressSystemWarnings(!isPositive);
112        continue;
113      }
114
115      // -Weverything is a special case as well.  It implicitly enables all
116      // warnings, including ones not explicitly in a warning group.
117      if (Opt == "everything") {
118        if (SetDiagnostic) {
119          if (isPositive) {
120            Diags.setEnableAllWarnings(true);
121          } else {
122            Diags.setEnableAllWarnings(false);
123            Diags.setMappingToAllDiagnostics(diag::MAP_IGNORE);
124          }
125        }
126        continue;
127      }
128
129      // -Werror/-Wno-error is a special case, not controlled by the option
130      // table. It also has the "specifier" form of -Werror=foo and -Werror-foo.
131      if (Opt.startswith("error")) {
132        StringRef Specifier;
133        if (Opt.size() > 5) {  // Specifier must be present.
134          if ((Opt[5] != '=' && Opt[5] != '-') || Opt.size() == 6) {
135            if (Report)
136              Diags.Report(diag::warn_unknown_warning_specifier)
137                << "-Werror" << ("-W" + OrigOpt.str());
138            continue;
139          }
140          Specifier = Opt.substr(6);
141        }
142
143        if (Specifier.empty()) {
144          if (SetDiagnostic)
145            Diags.setWarningsAsErrors(isPositive);
146          continue;
147        }
148
149        if (SetDiagnostic) {
150          // Set the warning as error flag for this specifier.
151          Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
152        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
153          EmitUnknownDiagWarning(Diags, "-Werror=", Specifier, isPositive);
154        }
155        continue;
156      }
157
158      // -Wfatal-errors is yet another special case.
159      if (Opt.startswith("fatal-errors")) {
160        StringRef Specifier;
161        if (Opt.size() != 12) {
162          if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
163            if (Report)
164              Diags.Report(diag::warn_unknown_warning_specifier)
165                << "-Wfatal-errors" << ("-W" + OrigOpt.str());
166            continue;
167          }
168          Specifier = Opt.substr(13);
169        }
170
171        if (Specifier.empty()) {
172          if (SetDiagnostic)
173            Diags.setErrorsAsFatal(isPositive);
174          continue;
175        }
176
177        if (SetDiagnostic) {
178          // Set the error as fatal flag for this specifier.
179          Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
180        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
181          EmitUnknownDiagWarning(Diags, "-Wfatal-errors=", Specifier,
182                                 isPositive);
183        }
184        continue;
185      }
186
187      if (Report) {
188        if (DiagIDs->getDiagnosticsInGroup(Opt, _Diags))
189          EmitUnknownDiagWarning(Diags, isPositive ? "-W" : "-Wno-", Opt,
190                                 isPositive);
191      } else {
192        Diags.setDiagnosticGroupMapping(Opt, Mapping);
193      }
194    }
195  }
196}
197