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>
32 using namespace clang;
33
34 // EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning
35 // opts
EmitUnknownDiagWarning(DiagnosticsEngine & Diags,StringRef Prefix,StringRef Opt,bool isPositive)36 static 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
ProcessWarningOptions(DiagnosticsEngine & Diags,const DiagnosticOptions & Opts,bool ReportDiags)50 void 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