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/Basic/DiagnosticOptions.h"
26#include "clang/Frontend/FrontendDiagnostic.h"
27#include "clang/Lex/LexDiagnostic.h"
28#include "clang/Sema/SemaDiagnostic.h"
29#include <algorithm>
30#include <cstring>
31#include <utility>
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                                  bool ReportDiags) {
53  Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
54  Diags.setIgnoreAllWarnings(Opts.IgnoreWarnings);
55  Diags.setShowOverloads(Opts.getShowOverloads());
56
57  Diags.setElideType(Opts.ElideType);
58  Diags.setPrintTemplateTree(Opts.ShowTemplateTree);
59  Diags.setShowColors(Opts.ShowColors);
60
61  // Handle -ferror-limit
62  if (Opts.ErrorLimit)
63    Diags.setErrorLimit(Opts.ErrorLimit);
64  if (Opts.TemplateBacktraceLimit)
65    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
66  if (Opts.ConstexprBacktraceLimit)
67    Diags.setConstexprBacktraceLimit(Opts.ConstexprBacktraceLimit);
68
69  // If -pedantic or -pedantic-errors was specified, then we want to map all
70  // extension diagnostics onto WARNING or ERROR unless the user has futz'd
71  // around with them explicitly.
72  if (Opts.PedanticErrors)
73    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Error);
74  else if (Opts.Pedantic)
75    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Warn);
76  else
77    Diags.setExtensionHandlingBehavior(DiagnosticsEngine::Ext_Ignore);
78
79  SmallVector<diag::kind, 10> _Diags;
80  const IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs =
81    Diags.getDiagnosticIDs();
82  // We parse the warning options twice.  The first pass sets diagnostic state,
83  // while the second pass reports warnings/errors.  This has the effect that
84  // we follow the more canonical "last option wins" paradigm when there are
85  // conflicting options.
86  for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) {
87    bool SetDiagnostic = (Report == 0);
88
89    // If we've set the diagnostic state and are not reporting diagnostics then
90    // we're done.
91    if (!SetDiagnostic && !ReportDiags)
92      break;
93
94    for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
95      StringRef Opt = Opts.Warnings[i];
96      StringRef OrigOpt = Opts.Warnings[i];
97
98      // Treat -Wformat=0 as an alias for -Wno-format.
99      if (Opt == "format=0")
100        Opt = "no-format";
101
102      // Check to see if this warning starts with "no-", if so, this is a
103      // negative form of the option.
104      bool isPositive = true;
105      if (Opt.startswith("no-")) {
106        isPositive = false;
107        Opt = Opt.substr(3);
108      }
109
110      // Figure out how this option affects the warning.  If -Wfoo, map the
111      // diagnostic to a warning, if -Wno-foo, map it to ignore.
112      diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
113
114      // -Wsystem-headers is a special case, not driven by the option table.  It
115      // cannot be controlled with -Werror.
116      if (Opt == "system-headers") {
117        if (SetDiagnostic)
118          Diags.setSuppressSystemWarnings(!isPositive);
119        continue;
120      }
121
122      // -Weverything is a special case as well.  It implicitly enables all
123      // warnings, including ones not explicitly in a warning group.
124      if (Opt == "everything") {
125        if (SetDiagnostic) {
126          if (isPositive) {
127            Diags.setEnableAllWarnings(true);
128          } else {
129            Diags.setEnableAllWarnings(false);
130            Diags.setMappingToAllDiagnostics(diag::MAP_IGNORE);
131          }
132        }
133        continue;
134      }
135
136      // -Werror/-Wno-error is a special case, not controlled by the option
137      // table. It also has the "specifier" form of -Werror=foo and -Werror-foo.
138      if (Opt.startswith("error")) {
139        StringRef Specifier;
140        if (Opt.size() > 5) {  // Specifier must be present.
141          if ((Opt[5] != '=' && Opt[5] != '-') || Opt.size() == 6) {
142            if (Report)
143              Diags.Report(diag::warn_unknown_warning_specifier)
144                << "-Werror" << ("-W" + OrigOpt.str());
145            continue;
146          }
147          Specifier = Opt.substr(6);
148        }
149
150        if (Specifier.empty()) {
151          if (SetDiagnostic)
152            Diags.setWarningsAsErrors(isPositive);
153          continue;
154        }
155
156        if (SetDiagnostic) {
157          // Set the warning as error flag for this specifier.
158          Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
159        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
160          EmitUnknownDiagWarning(Diags, "-Werror=", Specifier, isPositive);
161        }
162        continue;
163      }
164
165      // -Wfatal-errors is yet another special case.
166      if (Opt.startswith("fatal-errors")) {
167        StringRef Specifier;
168        if (Opt.size() != 12) {
169          if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
170            if (Report)
171              Diags.Report(diag::warn_unknown_warning_specifier)
172                << "-Wfatal-errors" << ("-W" + OrigOpt.str());
173            continue;
174          }
175          Specifier = Opt.substr(13);
176        }
177
178        if (Specifier.empty()) {
179          if (SetDiagnostic)
180            Diags.setErrorsAsFatal(isPositive);
181          continue;
182        }
183
184        if (SetDiagnostic) {
185          // Set the error as fatal flag for this specifier.
186          Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
187        } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
188          EmitUnknownDiagWarning(Diags, "-Wfatal-errors=", Specifier,
189                                 isPositive);
190        }
191        continue;
192      }
193
194      if (Report) {
195        if (DiagIDs->getDiagnosticsInGroup(Opt, _Diags))
196          EmitUnknownDiagWarning(Diags, isPositive ? "-W" : "-Wno-", Opt,
197                                 isPositive);
198      } else {
199        Diags.setDiagnosticGroupMapping(Opt, Mapping);
200      }
201    }
202  }
203}
204