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