clang 19.0.0git
Warnings.cpp
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1//===--- Warnings.cpp - C-Language Front-end ------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Command line warning options handler.
10//
11//===----------------------------------------------------------------------===//
12//
13// This file is responsible for handling all warning options. This includes
14// a number of -Wfoo options and their variants, which are driven by TableGen-
15// generated data, and the special cases -pedantic, -pedantic-errors, -w,
16// -Werror and -Wfatal-errors.
17//
18// Each warning option controls any number of actual warnings.
19// Given a warning option 'foo', the following are valid:
20// -Wfoo, -Wno-foo, -Werror=foo, -Wfatal-errors=foo
21//
22// Remark options are also handled here, analogously, except that they are much
23// simpler because a remark can't be promoted to an error.
27#include <algorithm>
28#include <cstring>
29#include <utility>
30using namespace clang;
31
32// EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning
33// opts
35 diag::Flavor Flavor, StringRef Prefix,
36 StringRef Opt) {
37 StringRef Suggestion = DiagnosticIDs::getNearestOption(Flavor, Opt);
38 Diags.Report(diag::warn_unknown_diag_option)
39 << (Flavor == diag::Flavor::WarningOrError ? 0 : 1)
40 << (Prefix.str() += std::string(Opt)) << !Suggestion.empty()
41 << (Prefix.str() += std::string(Suggestion));
42}
43
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
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 = !Opt.consume_front("no-");
100
101 // Figure out how this option affects the warning. If -Wfoo, map the
102 // diagnostic to a warning, if -Wno-foo, map it to ignore.
103 diag::Severity Mapping =
104 isPositive ? diag::Severity::Warning : diag::Severity::Ignored;
105
106 // -Wsystem-headers is a special case, not driven by the option table. It
107 // cannot be controlled with -Werror.
108 if (Opt == "system-headers") {
109 if (SetDiagnostic)
110 Diags.setSuppressSystemWarnings(!isPositive);
111 continue;
112 }
113
114 // -Weverything is a special case as well. It implicitly enables all
115 // warnings, including ones not explicitly in a warning group.
116 if (Opt == "everything") {
117 if (SetDiagnostic) {
118 if (isPositive) {
119 Diags.setEnableAllWarnings(true);
120 } else {
121 Diags.setEnableAllWarnings(false);
122 Diags.setSeverityForAll(Flavor, diag::Severity::Ignored);
123 }
124 }
125 continue;
126 }
127
128 // -Werror/-Wno-error is a special case, not controlled by the option
129 // table. It also has the "specifier" form of -Werror=foo. GCC supports
130 // the deprecated -Werror-implicit-function-declaration which is used by
131 // a few projects.
132 if (Opt.starts_with("error")) {
133 StringRef Specifier;
134 if (Opt.size() > 5) { // Specifier must be present.
135 if (Opt[5] != '=' &&
136 Opt.substr(5) != "-implicit-function-declaration") {
137 if (Report)
138 Diags.Report(diag::warn_unknown_warning_specifier)
139 << "-Werror" << ("-W" + OrigOpt.str());
140 continue;
141 }
142 Specifier = Opt.substr(6);
143 }
144
145 if (Specifier.empty()) {
146 if (SetDiagnostic)
147 Diags.setWarningsAsErrors(isPositive);
148 continue;
149 }
150
151 if (SetDiagnostic) {
152 // Set the warning as error flag for this specifier.
154 } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) {
155 EmitUnknownDiagWarning(Diags, Flavor, "-Werror=", Specifier);
156 }
157 continue;
158 }
159
160 // -Wfatal-errors is yet another special case.
161 if (Opt.starts_with("fatal-errors")) {
162 StringRef Specifier;
163 if (Opt.size() != 12) {
164 if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
165 if (Report)
166 Diags.Report(diag::warn_unknown_warning_specifier)
167 << "-Wfatal-errors" << ("-W" + OrigOpt.str());
168 continue;
169 }
170 Specifier = Opt.substr(13);
171 }
172
173 if (Specifier.empty()) {
174 if (SetDiagnostic)
175 Diags.setErrorsAsFatal(isPositive);
176 continue;
177 }
178
179 if (SetDiagnostic) {
180 // Set the error as fatal flag for this specifier.
181 Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
182 } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) {
183 EmitUnknownDiagWarning(Diags, Flavor, "-Wfatal-errors=", Specifier);
184 }
185 continue;
186 }
187
188 if (Report) {
189 if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags))
190 EmitUnknownDiagWarning(Diags, Flavor, isPositive ? "-W" : "-Wno-",
191 Opt);
192 } else {
193 Diags.setSeverityForGroup(Flavor, Opt, Mapping);
194 }
195 }
196
197 for (StringRef Opt : Opts.Remarks) {
198 const auto Flavor = diag::Flavor::Remark;
199
200 // Check to see if this warning starts with "no-", if so, this is a
201 // negative form of the option.
202 bool IsPositive = !Opt.consume_front("no-");
203
204 auto Severity = IsPositive ? diag::Severity::Remark
205 : diag::Severity::Ignored;
206
207 // -Reverything sets the state of all remarks. Note that all remarks are
208 // in remark groups, so we don't need a separate 'all remarks enabled'
209 // flag.
210 if (Opt == "everything") {
211 if (SetDiagnostic)
212 Diags.setSeverityForAll(Flavor, Severity);
213 continue;
214 }
215
216 if (Report) {
217 if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags))
218 EmitUnknownDiagWarning(Diags, Flavor, IsPositive ? "-R" : "-Rno-",
219 Opt);
220 } else {
221 Diags.setSeverityForGroup(Flavor, Opt,
222 IsPositive ? diag::Severity::Remark
223 : diag::Severity::Ignored);
224 }
225 }
226 }
227}
Includes all the separate Diagnostic headers & some related helpers.
Defines the Diagnostic-related interfaces.
const NestedNameSpecifier * Specifier
static void EmitUnknownDiagWarning(DiagnosticsEngine &Diags, diag::Flavor Flavor, StringRef Prefix, StringRef Opt)
Definition: Warnings.cpp:34
static StringRef getNearestOption(diag::Flavor Flavor, StringRef Group)
Get the diagnostic option with the closest edit distance to the given group name.
Options for controlling the compiler diagnostics engine.
std::vector< std::string > Remarks
The list of -R... options used to alter the diagnostic mappings, with the prefixes removed.
std::vector< std::string > Warnings
The list of -W... options used to alter the diagnostic mappings, with the prefixes removed.
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:192
void setErrorsAsFatal(bool Val)
When set to true, any error reported is made a fatal error.
Definition: Diagnostic.h:677
DiagnosticBuilder Report(SourceLocation Loc, unsigned DiagID)
Issue the message to the client.
Definition: Diagnostic.h:1547
void setPrintTemplateTree(bool Val)
Set tree printing, to outputting the template difference in a tree format.
Definition: Diagnostic.h:707
void setSuppressSystemWarnings(bool Val)
When set to true mask warnings that come from system headers.
Definition: Diagnostic.h:687
void setSeverityForAll(diag::Flavor Flavor, diag::Severity Map, SourceLocation Loc=SourceLocation())
Add the specified mapping to all diagnostics of the specified flavor.
Definition: Diagnostic.cpp:486
void setIgnoreAllWarnings(bool Val)
When set to true, any unmapped warnings are ignored.
Definition: Diagnostic.h:650
void setExtensionHandlingBehavior(diag::Severity H)
Controls whether otherwise-unmapped extension diagnostics are mapped onto ignore/warning/error.
Definition: Diagnostic.h:778
void setTemplateBacktraceLimit(unsigned Limit)
Specify the maximum number of template instantiation notes to emit along with a given diagnostic.
Definition: Diagnostic.h:625
void setErrorLimit(unsigned Limit)
Specify a limit for the number of errors we should emit before giving up.
Definition: Diagnostic.h:621
void setWarningsAsErrors(bool Val)
When set to true, any warnings reported are issued as errors.
Definition: Diagnostic.h:669
void setShowOverloads(OverloadsShown Val)
Specify which overload candidates to show when overload resolution fails.
Definition: Diagnostic.h:719
void setEnableAllWarnings(bool Val)
When set to true, any unmapped ignored warnings are no longer ignored.
Definition: Diagnostic.h:661
void setConstexprBacktraceLimit(unsigned Limit)
Specify the maximum number of constexpr evaluation notes to emit along with a given diagnostic.
Definition: Diagnostic.h:637
bool setDiagnosticGroupErrorAsFatal(StringRef Group, bool Enabled)
Set the error-as-fatal flag for the given diagnostic group.
Definition: Diagnostic.cpp:456
void setShowColors(bool Val)
Set color printing, so the type diffing will inject color markers into the output.
Definition: Diagnostic.h:712
bool setDiagnosticGroupWarningAsError(StringRef Group, bool Enabled)
Set the warning-as-error flag for the given diagnostic group.
Definition: Diagnostic.cpp:425
bool setSeverityForGroup(diag::Flavor Flavor, StringRef Group, diag::Severity Map, SourceLocation Loc=SourceLocation())
Change an entire diagnostic group (e.g.
Definition: Diagnostic.cpp:402
void setElideType(bool Val)
Set type eliding, to skip outputting same types occurring in template types.
Definition: Diagnostic.h:702
const IntrusiveRefCntPtr< DiagnosticIDs > & getDiagnosticIDs() const
Definition: Diagnostic.h:557
Severity
Enum values that allow the client to map NOTEs, WARNINGs, and EXTENSIONs to either Ignore (nothing),...
Definition: DiagnosticIDs.h:85
Flavor
Flavors of diagnostics we can emit.
Definition: DiagnosticIDs.h:96
The JSON file list parser is used to communicate input to InstallAPI.
void ProcessWarningOptions(DiagnosticsEngine &Diags, const DiagnosticOptions &Opts, bool ReportDiags=true)
ProcessWarningOptions - Initialize the diagnostic client and process the warning options specified on...
Definition: Warnings.cpp:44