clang  13.0.0git
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.
25 #include "clang/Basic/Diagnostic.h"
27 #include <algorithm>
28 #include <cstring>
29 #include <utility>
30 using 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)
68  else if (Opts.Pedantic)
70  else
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) {
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 = true;
100  if (Opt.startswith("no-")) {
101  isPositive = false;
102  Opt = Opt.substr(3);
103  }
104 
105  // Figure out how this option affects the warning. If -Wfoo, map the
106  // diagnostic to a warning, if -Wno-foo, map it to ignore.
107  diag::Severity Mapping =
109 
110  // -Wsystem-headers is a special case, not driven by the option table. It
111  // cannot be controlled with -Werror.
112  if (Opt == "system-headers") {
113  if (SetDiagnostic)
114  Diags.setSuppressSystemWarnings(!isPositive);
115  continue;
116  }
117 
118  // -Weverything is a special case as well. It implicitly enables all
119  // warnings, including ones not explicitly in a warning group.
120  if (Opt == "everything") {
121  if (SetDiagnostic) {
122  if (isPositive) {
123  Diags.setEnableAllWarnings(true);
124  } else {
125  Diags.setEnableAllWarnings(false);
127  }
128  }
129  continue;
130  }
131 
132  // -Werror/-Wno-error is a special case, not controlled by the option
133  // table. It also has the "specifier" form of -Werror=foo. GCC supports
134  // the deprecated -Werror-implicit-function-declaration which is used by
135  // a few projects.
136  if (Opt.startswith("error")) {
137  StringRef Specifier;
138  if (Opt.size() > 5) { // Specifier must be present.
139  if (Opt[5] != '=' &&
140  Opt.substr(5) != "-implicit-function-declaration") {
141  if (Report)
142  Diags.Report(diag::warn_unknown_warning_specifier)
143  << "-Werror" << ("-W" + OrigOpt.str());
144  continue;
145  }
146  Specifier = Opt.substr(6);
147  }
148 
149  if (Specifier.empty()) {
150  if (SetDiagnostic)
151  Diags.setWarningsAsErrors(isPositive);
152  continue;
153  }
154 
155  if (SetDiagnostic) {
156  // Set the warning as error flag for this specifier.
157  Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive);
158  } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) {
159  EmitUnknownDiagWarning(Diags, Flavor, "-Werror=", Specifier);
160  }
161  continue;
162  }
163 
164  // -Wfatal-errors is yet another special case.
165  if (Opt.startswith("fatal-errors")) {
166  StringRef Specifier;
167  if (Opt.size() != 12) {
168  if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) {
169  if (Report)
170  Diags.Report(diag::warn_unknown_warning_specifier)
171  << "-Wfatal-errors" << ("-W" + OrigOpt.str());
172  continue;
173  }
174  Specifier = Opt.substr(13);
175  }
176 
177  if (Specifier.empty()) {
178  if (SetDiagnostic)
179  Diags.setErrorsAsFatal(isPositive);
180  continue;
181  }
182 
183  if (SetDiagnostic) {
184  // Set the error as fatal flag for this specifier.
185  Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive);
186  } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) {
187  EmitUnknownDiagWarning(Diags, Flavor, "-Wfatal-errors=", Specifier);
188  }
189  continue;
190  }
191 
192  if (Report) {
193  if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags))
194  EmitUnknownDiagWarning(Diags, Flavor, isPositive ? "-W" : "-Wno-",
195  Opt);
196  } else {
197  Diags.setSeverityForGroup(Flavor, Opt, Mapping);
198  }
199  }
200 
201  for (unsigned i = 0, e = Opts.Remarks.size(); i != e; ++i) {
202  StringRef Opt = Opts.Remarks[i];
203  const auto Flavor = diag::Flavor::Remark;
204 
205  // Check to see if this warning starts with "no-", if so, this is a
206  // negative form of the option.
207  bool IsPositive = !Opt.startswith("no-");
208  if (!IsPositive) Opt = Opt.substr(3);
209 
210  auto Severity = IsPositive ? diag::Severity::Remark
212 
213  // -Reverything sets the state of all remarks. Note that all remarks are
214  // in remark groups, so we don't need a separate 'all remarks enabled'
215  // flag.
216  if (Opt == "everything") {
217  if (SetDiagnostic)
219  continue;
220  }
221 
222  if (Report) {
223  if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags))
224  EmitUnknownDiagWarning(Diags, Flavor, IsPositive ? "-R" : "-Rno-",
225  Opt);
226  } else {
227  Diags.setSeverityForGroup(Flavor, Opt,
228  IsPositive ? diag::Severity::Remark
230  }
231  }
232  }
233 }
clang::diag::Severity
Severity
Enum values that allow the client to map NOTEs, WARNINGs, and EXTENSIONs to either Ignore (nothing),...
Definition: DiagnosticIDs.h:80
clang::diag::Severity::Error
@ Error
Present this diagnostic as an error.
string
string(SUBSTRING ${CMAKE_CURRENT_BINARY_DIR} 0 ${PATH_LIB_START} PATH_HEAD) string(SUBSTRING $
Definition: CMakeLists.txt:22
clang::ProcessWarningOptions
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
clang::DiagnosticsEngine::setConstexprBacktraceLimit
void setConstexprBacktraceLimit(unsigned Limit)
Specify the maximum number of constexpr evaluation notes to emit along with a given diagnostic.
Definition: Diagnostic.h:630
llvm::SmallVector
Definition: LLVM.h:38
clang::DiagnosticsEngine::setDiagnosticGroupErrorAsFatal
bool setDiagnosticGroupErrorAsFatal(StringRef Group, bool Enabled)
Set the error-as-fatal flag for the given diagnostic group.
Definition: Diagnostic.cpp:442
clang::DiagnosticsEngine::setIgnoreAllWarnings
void setIgnoreAllWarnings(bool Val)
When set to true, any unmapped warnings are ignored.
Definition: Diagnostic.h:643
EmitUnknownDiagWarning
static void EmitUnknownDiagWarning(DiagnosticsEngine &Diags, diag::Flavor Flavor, StringRef Prefix, StringRef Opt)
Definition: Warnings.cpp:34
clang::DiagnosticsEngine
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:191
clang::diag::Severity::Remark
@ Remark
Present this diagnostic as a remark.
clang::DiagnosticsEngine::setEnableAllWarnings
void setEnableAllWarnings(bool Val)
When set to true, any unmapped ignored warnings are no longer ignored.
Definition: Diagnostic.h:654
clang::DiagnosticsEngine::setElideType
void setElideType(bool Val)
Set type eliding, to skip outputting same types occurring in template types.
Definition: Diagnostic.h:695
clang::DiagnosticsEngine::setSeverityForGroup
bool setSeverityForGroup(diag::Flavor Flavor, StringRef Group, diag::Severity Map, SourceLocation Loc=SourceLocation())
Change an entire diagnostic group (e.g.
Definition: Diagnostic.cpp:396
clang::DiagnosticsEngine::setPrintTemplateTree
void setPrintTemplateTree(bool Val)
Set tree printing, to outputting the template difference in a tree format.
Definition: Diagnostic.h:700
clang::DiagnosticsEngine::setDiagnosticGroupWarningAsError
bool setDiagnosticGroupWarningAsError(StringRef Group, bool Enabled)
Set the warning-as-error flag for the given diagnostic group.
Definition: Diagnostic.cpp:411
clang::diag::Severity::Ignored
@ Ignored
Do not present this diagnostic, ignore it.
clang::DiagnosticsEngine::setErrorLimit
void setErrorLimit(unsigned Limit)
Specify a limit for the number of errors we should emit before giving up.
Definition: Diagnostic.h:614
clang::diag::Flavor::WarningOrError
@ WarningOrError
A diagnostic that indicates a problem or potential problem.
AllDiagnostics.h
clang::DiagnosticsEngine::setExtensionHandlingBehavior
void setExtensionHandlingBehavior(diag::Severity H)
Controls whether otherwise-unmapped extension diagnostics are mapped onto ignore/warning/error.
Definition: Diagnostic.h:771
clang::DiagnosticsEngine::setSuppressSystemWarnings
void setSuppressSystemWarnings(bool Val)
When set to true mask warnings that come from system headers.
Definition: Diagnostic.h:680
Diagnostic.h
clang::DiagnosticsEngine::getDiagnosticIDs
const IntrusiveRefCntPtr< DiagnosticIDs > & getDiagnosticIDs() const
Definition: Diagnostic.h:550
clang::DiagnosticsEngine::setShowColors
void setShowColors(bool Val)
Set color printing, so the type diffing will inject color markers into the output.
Definition: Diagnostic.h:705
clang::diag::Severity::Warning
@ Warning
Present this diagnostic as a warning.
clang::DiagnosticsEngine::setWarningsAsErrors
void setWarningsAsErrors(bool Val)
When set to true, any warnings reported are issued as errors.
Definition: Diagnostic.h:662
clang::DiagnosticOptions::Warnings
std::vector< std::string > Warnings
The list of -W...
Definition: DiagnosticOptions.h:111
Specifier
const NestedNameSpecifier * Specifier
Definition: USRLocFinder.cpp:173
clang::diag::Flavor
Flavor
Flavors of diagnostics we can emit.
Definition: DiagnosticIDs.h:91
clang::DiagnosticOptions::Remarks
std::vector< std::string > Remarks
The list of -R...
Definition: DiagnosticOptions.h:119
clang::diag::Flavor::Remark
@ Remark
A diagnostic that indicates normal progress through compilation.
clang::DiagnosticsEngine::setErrorsAsFatal
void setErrorsAsFatal(bool Val)
When set to true, any error reported is made a fatal error.
Definition: Diagnostic.h:670
clang
Dataflow Directional Tag Classes.
Definition: CalledOnceCheck.h:17
clang::DiagnosticsEngine::setShowOverloads
void setShowOverloads(OverloadsShown Val)
Specify which overload candidates to show when overload resolution fails.
Definition: Diagnostic.h:712
clang::DiagnosticsEngine::setTemplateBacktraceLimit
void setTemplateBacktraceLimit(unsigned Limit)
Specify the maximum number of template instantiation notes to emit along with a given diagnostic.
Definition: Diagnostic.h:618
DiagnosticOptions.h
clang::DiagnosticsEngine::setSeverityForAll
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:472
clang::DiagnosticIDs::getNearestOption
static StringRef getNearestOption(diag::Flavor Flavor, StringRef Group)
Get the diagnostic option with the closest edit distance to the given group name.
Definition: DiagnosticIDs.cpp:686
llvm::IntrusiveRefCntPtr
Definition: LLVM.h:47
clang::DiagnosticOptions
Options for controlling the compiler diagnostics engine.
Definition: DiagnosticOptions.h:70
clang::DiagnosticsEngine::Report
DiagnosticBuilder Report(SourceLocation Loc, unsigned DiagID)
Issue the message to the client.
Definition: Diagnostic.h:1508