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// Remark options are also handled here, analogously, except that they are much
24// simpler because a remark can't be promoted to an error.
25#include "clang/Basic/AllDiagnostics.h"
26#include "clang/Basic/Diagnostic.h"
27#include "clang/Basic/DiagnosticOptions.h"
28#include <algorithm>
29#include <cstring>
30#include <utility>
31using namespace clang;
32
33// EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning
34// opts
35static void EmitUnknownDiagWarning(DiagnosticsEngine &Diags,
36                                   diag::Flavor Flavor, StringRef Prefix,
37                                   StringRef Opt) {
38  StringRef Suggestion = DiagnosticIDs::getNearestOption(Flavor, Opt);
39  Diags.Report(diag::warn_unknown_diag_option)
40    << (Flavor == diag::Flavor::WarningOrError ? 0 : 1) << (Prefix.str() += Opt)
41    << !Suggestion.empty() << (Prefix.str() += Suggestion);
42}
43
44void clang::ProcessWarningOptions(DiagnosticsEngine &Diags,
45                                  const DiagnosticOptions &Opts,
46                                  bool ReportDiags) {
47  Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
48  Diags.setIgnoreAllWarnings(Opts.IgnoreWarnings);
49  Diags.setShowOverloads(Opts.getShowOverloads());
50
51  Diags.setElideType(Opts.ElideType);
52  Diags.setPrintTemplateTree(Opts.ShowTemplateTree);
53  Diags.setShowColors(Opts.ShowColors);
54
55  // Handle -ferror-limit
56  if (Opts.ErrorLimit)
57    Diags.setErrorLimit(Opts.ErrorLimit);
58  if (Opts.TemplateBacktraceLimit)
59    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
60  if (Opts.ConstexprBacktraceLimit)
61    Diags.setConstexprBacktraceLimit(Opts.ConstexprBacktraceLimit);
62
63  // If -pedantic or -pedantic-errors was specified, then we want to map all
64  // extension diagnostics onto WARNING or ERROR unless the user has futz'd
65  // around with them explicitly.
66  if (Opts.PedanticErrors)
67    Diags.setExtensionHandlingBehavior(diag::Severity::Error);
68  else if (Opts.Pedantic)
69    Diags.setExtensionHandlingBehavior(diag::Severity::Warning);
70  else
71    Diags.setExtensionHandlingBehavior(diag::Severity::Ignored);
72
73  SmallVector<diag::kind, 10> _Diags;
74  const IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs =
75    Diags.getDiagnosticIDs();
76  // We parse the warning options twice.  The first pass sets diagnostic state,
77  // while the second pass reports warnings/errors.  This has the effect that
78  // we follow the more canonical "last option wins" paradigm when there are
79  // conflicting options.
80  for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) {
81    bool SetDiagnostic = (Report == 0);
82
83    // If we've set the diagnostic state and are not reporting diagnostics then
84    // we're done.
85    if (!SetDiagnostic && !ReportDiags)
86      break;
87
88    for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
89      const auto Flavor = diag::Flavor::WarningOrError;
90      StringRef Opt = Opts.Warnings[i];
91      StringRef OrigOpt = Opts.Warnings[i];
92
93      // Treat -Wformat=0 as an alias for -Wno-format.
94      if (Opt == "format=0")
95        Opt = "no-format";
96
97      // Check to see if this warning starts with "no-", if so, this is a
98      // negative form of the option.
99      bool isPositive = true;
100      if (Opt.startswith("no-")) {
101        isPositive = false;
102        Opt = Opt.substr(3);
103      }
104
105      // Figure out how this option affects the warning.  If -Wfoo, map the
106      // diagnostic to a warning, if -Wno-foo, map it to ignore.
107      diag::Severity Mapping =
108          isPositive ? diag::Severity::Warning : diag::Severity::Ignored;
109
110      // -Wsystem-headers is a special case, not driven by the option table.  It
111      // cannot be controlled with -Werror.
112      if (Opt == "system-headers") {
113        if (SetDiagnostic)
114          Diags.setSuppressSystemWarnings(!isPositive);
115        continue;
116      }
117
118      // -Weverything is a special case as well.  It implicitly enables all
119      // warnings, including ones not explicitly in a warning group.
120      if (Opt == "everything") {
121        if (SetDiagnostic) {
122          if (isPositive) {
123            Diags.setEnableAllWarnings(true);
124          } else {
125            Diags.setEnableAllWarnings(false);
126            Diags.setSeverityForAll(Flavor, diag::Severity::Ignored);
127          }
128        }
129        continue;
130      }
131
132      // -Werror/-Wno-error is a special case, not controlled by the option
133      // table. It also has the "specifier" form of -Werror=foo and -Werror-foo.
134      if (Opt.startswith("error")) {
135        StringRef Specifier;
136        if (Opt.size() > 5) {  // Specifier must be present.
137          if ((Opt[5] != '=' && Opt[5] != '-') || Opt.size() == 6) {
138            if (Report)
139              Diags.Report(diag::warn_unknown_warning_specifier)
140                << "-Werror" << ("-W" + OrigOpt.str());
141            continue;
142          }
143          Specifier = Opt.substr(6);
144        }
145
146        if (Specifier.empty()) {
147          if (SetDiagnostic)
148            Diags.setWarningsAsErrors(isPositive);
149          continue;
150        }
151
152        if (SetDiagnostic) {
153          // Set the warning as error flag for this specifier.
154          Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
155        } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) {
156          EmitUnknownDiagWarning(Diags, Flavor, "-Werror=", Specifier);
157        }
158        continue;
159      }
160
161      // -Wfatal-errors is yet another special case.
162      if (Opt.startswith("fatal-errors")) {
163        StringRef Specifier;
164        if (Opt.size() != 12) {
165          if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
166            if (Report)
167              Diags.Report(diag::warn_unknown_warning_specifier)
168                << "-Wfatal-errors" << ("-W" + OrigOpt.str());
169            continue;
170          }
171          Specifier = Opt.substr(13);
172        }
173
174        if (Specifier.empty()) {
175          if (SetDiagnostic)
176            Diags.setErrorsAsFatal(isPositive);
177          continue;
178        }
179
180        if (SetDiagnostic) {
181          // Set the error as fatal flag for this specifier.
182          Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
183        } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) {
184          EmitUnknownDiagWarning(Diags, Flavor, "-Wfatal-errors=", Specifier);
185        }
186        continue;
187      }
188
189      if (Report) {
190        if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags))
191          EmitUnknownDiagWarning(Diags, Flavor, isPositive ? "-W" : "-Wno-",
192                                 Opt);
193      } else {
194        Diags.setSeverityForGroup(Flavor, Opt, Mapping);
195      }
196    }
197
198    for (unsigned i = 0, e = Opts.Remarks.size(); i != e; ++i) {
199      StringRef Opt = Opts.Remarks[i];
200      const auto Flavor = diag::Flavor::Remark;
201
202      // Check to see if this warning starts with "no-", if so, this is a
203      // negative form of the option.
204      bool IsPositive = !Opt.startswith("no-");
205      if (!IsPositive) Opt = Opt.substr(3);
206
207      auto Severity = IsPositive ? diag::Severity::Remark
208                                 : diag::Severity::Ignored;
209
210      // -Reverything sets the state of all remarks. Note that all remarks are
211      // in remark groups, so we don't need a separate 'all remarks enabled'
212      // flag.
213      if (Opt == "everything") {
214        if (SetDiagnostic)
215          Diags.setSeverityForAll(Flavor, Severity);
216        continue;
217      }
218
219      if (Report) {
220        if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags))
221          EmitUnknownDiagWarning(Diags, Flavor, IsPositive ? "-R" : "-Rno-",
222                                 Opt);
223      } else {
224        Diags.setSeverityForGroup(Flavor, Opt,
225                                  IsPositive ? diag::Severity::Remark
226                                             : diag::Severity::Ignored);
227      }
228    }
229  }
230}
231