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/Frontend/DiagnosticOptions.h"
28 #include "clang/Frontend/FrontendDiagnostic.h"
29 #include <cstring>
30 #include <utility>
31 #include <algorithm>
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)50 void 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(
55 static_cast<DiagnosticsEngine::OverloadsShown>(Opts.ShowOverloads));
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 llvm::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 for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
89 StringRef Opt = Opts.Warnings[i];
90 StringRef OrigOpt = Opts.Warnings[i];
91
92 // Treat -Wformat=0 as an alias for -Wno-format.
93 if (Opt == "format=0")
94 Opt = "no-format";
95
96 // Check to see if this warning starts with "no-", if so, this is a
97 // negative form of the option.
98 bool isPositive = true;
99 if (Opt.startswith("no-")) {
100 isPositive = false;
101 Opt = Opt.substr(3);
102 }
103
104 // Figure out how this option affects the warning. If -Wfoo, map the
105 // diagnostic to a warning, if -Wno-foo, map it to ignore.
106 diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
107
108 // -Wsystem-headers is a special case, not driven by the option table. It
109 // cannot be controlled with -Werror.
110 if (Opt == "system-headers") {
111 if (SetDiagnostic)
112 Diags.setSuppressSystemWarnings(!isPositive);
113 continue;
114 }
115
116 // -Weverything is a special case as well. It implicitly enables all
117 // warnings, including ones not explicitly in a warning group.
118 if (Opt == "everything") {
119 if (SetDiagnostic) {
120 if (isPositive) {
121 Diags.setEnableAllWarnings(true);
122 } else {
123 Diags.setEnableAllWarnings(false);
124 Diags.setMappingToAllDiagnostics(diag::MAP_IGNORE);
125 }
126 }
127 continue;
128 }
129
130 // -Werror/-Wno-error is a special case, not controlled by the option
131 // table. It also has the "specifier" form of -Werror=foo and -Werror-foo.
132 if (Opt.startswith("error")) {
133 StringRef Specifier;
134 if (Opt.size() > 5) { // Specifier must be present.
135 if ((Opt[5] != '=' && Opt[5] != '-') || Opt.size() == 6) {
136 if (Report)
137 Diags.Report(diag::warn_unknown_warning_specifier)
138 << "-Werror" << ("-W" + OrigOpt.str());
139 continue;
140 }
141 Specifier = Opt.substr(6);
142 }
143
144 if (Specifier.empty()) {
145 if (SetDiagnostic)
146 Diags.setWarningsAsErrors(isPositive);
147 continue;
148 }
149
150 if (SetDiagnostic) {
151 // Set the warning as error flag for this specifier.
152 Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
153 } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
154 EmitUnknownDiagWarning(Diags, "-Werror=", Specifier, isPositive);
155 }
156 continue;
157 }
158
159 // -Wfatal-errors is yet another special case.
160 if (Opt.startswith("fatal-errors")) {
161 StringRef Specifier;
162 if (Opt.size() != 12) {
163 if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
164 if (Report)
165 Diags.Report(diag::warn_unknown_warning_specifier)
166 << "-Wfatal-errors" << ("-W" + OrigOpt.str());
167 continue;
168 }
169 Specifier = Opt.substr(13);
170 }
171
172 if (Specifier.empty()) {
173 if (SetDiagnostic)
174 Diags.setErrorsAsFatal(isPositive);
175 continue;
176 }
177
178 if (SetDiagnostic) {
179 // Set the error as fatal flag for this specifier.
180 Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
181 } else if (DiagIDs->getDiagnosticsInGroup(Specifier, _Diags)) {
182 EmitUnknownDiagWarning(Diags, "-Wfatal-errors=", Specifier,
183 isPositive);
184 }
185 continue;
186 }
187
188 if (Report) {
189 if (DiagIDs->getDiagnosticsInGroup(Opt, _Diags))
190 EmitUnknownDiagWarning(Diags, isPositive ? "-W" : "-Wno-", Opt,
191 isPositive);
192 } else {
193 Diags.setDiagnosticGroupMapping(Opt, Mapping);
194 }
195 }
196 }
197 }
198