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. 24 #include "clang/Basic/AllDiagnostics.h" 25 #include "clang/Basic/Diagnostic.h" 26 #include "clang/Basic/DiagnosticDriver.h" 27 #include "clang/Basic/DiagnosticIDs.h" 28 #include "clang/Basic/DiagnosticOptions.h" 29 #include "llvm/ADT/StringRef.h" 30 #include "llvm/Support/VirtualFileSystem.h" 31 #include <cstring> 32 using namespace clang; 33 34 // EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning 35 // opts 36 static void EmitUnknownDiagWarning(DiagnosticsEngine &Diags, 37 diag::Flavor Flavor, StringRef Prefix, 38 StringRef Opt) { 39 StringRef Suggestion = DiagnosticIDs::getNearestOption(Flavor, Opt); 40 Diags.Report(diag::warn_unknown_diag_option) 41 << (Flavor == diag::Flavor::WarningOrError ? 0 : 1) 42 << (Prefix.str() += std::string(Opt)) << !Suggestion.empty() 43 << (Prefix.str() += std::string(Suggestion)); 44 } 45 46 void clang::ProcessWarningOptions(DiagnosticsEngine &Diags, 47 const DiagnosticOptions &Opts, 48 llvm::vfs::FileSystem &VFS, 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 if (!Opts.DiagnosticSuppressionMappingsFile.empty()) { 77 if (auto FileContents = 78 VFS.getBufferForFile(Opts.DiagnosticSuppressionMappingsFile)) { 79 Diags.setDiagSuppressionMapping(**FileContents); 80 } else if (ReportDiags) { 81 Diags.Report(diag::err_drv_no_such_file) 82 << Opts.DiagnosticSuppressionMappingsFile; 83 } 84 } 85 86 SmallVector<diag::kind, 10> _Diags; 87 const IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs = 88 Diags.getDiagnosticIDs(); 89 // We parse the warning options twice. The first pass sets diagnostic state, 90 // while the second pass reports warnings/errors. This has the effect that 91 // we follow the more canonical "last option wins" paradigm when there are 92 // conflicting options. 93 for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) { 94 bool SetDiagnostic = (Report == 0); 95 96 // If we've set the diagnostic state and are not reporting diagnostics then 97 // we're done. 98 if (!SetDiagnostic && !ReportDiags) 99 break; 100 101 for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) { 102 const auto Flavor = diag::Flavor::WarningOrError; 103 StringRef Opt = Opts.Warnings[i]; 104 StringRef OrigOpt = Opts.Warnings[i]; 105 106 // Treat -Wformat=0 as an alias for -Wno-format. 107 if (Opt == "format=0") 108 Opt = "no-format"; 109 110 // Check to see if this warning starts with "no-", if so, this is a 111 // negative form of the option. 112 bool isPositive = !Opt.consume_front("no-"); 113 114 // Figure out how this option affects the warning. If -Wfoo, map the 115 // diagnostic to a warning, if -Wno-foo, map it to ignore. 116 diag::Severity Mapping = 117 isPositive ? diag::Severity::Warning : diag::Severity::Ignored; 118 119 // -Wsystem-headers is a special case, not driven by the option table. It 120 // cannot be controlled with -Werror. 121 if (Opt == "system-headers") { 122 if (SetDiagnostic) 123 Diags.setSuppressSystemWarnings(!isPositive); 124 continue; 125 } 126 127 // -Weverything is a special case as well. It implicitly enables all 128 // warnings, including ones not explicitly in a warning group. 129 if (Opt == "everything") { 130 if (SetDiagnostic) { 131 if (isPositive) { 132 Diags.setEnableAllWarnings(true); 133 } else { 134 Diags.setEnableAllWarnings(false); 135 Diags.setSeverityForAll(Flavor, diag::Severity::Ignored); 136 } 137 } 138 continue; 139 } 140 141 // -Werror/-Wno-error is a special case, not controlled by the option 142 // table. It also has the "specifier" form of -Werror=foo. GCC supports 143 // the deprecated -Werror-implicit-function-declaration which is used by 144 // a few projects. 145 if (Opt.starts_with("error")) { 146 StringRef Specifier; 147 if (Opt.size() > 5) { // Specifier must be present. 148 if (Opt[5] != '=' && 149 Opt.substr(5) != "-implicit-function-declaration") { 150 if (Report) 151 Diags.Report(diag::warn_unknown_warning_specifier) 152 << "-Werror" << ("-W" + OrigOpt.str()); 153 continue; 154 } 155 Specifier = Opt.substr(6); 156 } 157 158 if (Specifier.empty()) { 159 if (SetDiagnostic) 160 Diags.setWarningsAsErrors(isPositive); 161 continue; 162 } 163 164 if (SetDiagnostic) { 165 // Set the warning as error flag for this specifier. 166 Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive); 167 } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) { 168 EmitUnknownDiagWarning(Diags, Flavor, "-Werror=", Specifier); 169 } 170 continue; 171 } 172 173 // -Wfatal-errors is yet another special case. 174 if (Opt.starts_with("fatal-errors")) { 175 StringRef Specifier; 176 if (Opt.size() != 12) { 177 if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) { 178 if (Report) 179 Diags.Report(diag::warn_unknown_warning_specifier) 180 << "-Wfatal-errors" << ("-W" + OrigOpt.str()); 181 continue; 182 } 183 Specifier = Opt.substr(13); 184 } 185 186 if (Specifier.empty()) { 187 if (SetDiagnostic) 188 Diags.setErrorsAsFatal(isPositive); 189 continue; 190 } 191 192 if (SetDiagnostic) { 193 // Set the error as fatal flag for this specifier. 194 Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive); 195 } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) { 196 EmitUnknownDiagWarning(Diags, Flavor, "-Wfatal-errors=", Specifier); 197 } 198 continue; 199 } 200 201 if (Report) { 202 if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags)) 203 EmitUnknownDiagWarning(Diags, Flavor, isPositive ? "-W" : "-Wno-", 204 Opt); 205 } else { 206 Diags.setSeverityForGroup(Flavor, Opt, Mapping); 207 } 208 } 209 210 for (StringRef Opt : Opts.Remarks) { 211 const auto Flavor = diag::Flavor::Remark; 212 213 // Check to see if this warning starts with "no-", if so, this is a 214 // negative form of the option. 215 bool IsPositive = !Opt.consume_front("no-"); 216 217 auto Severity = IsPositive ? diag::Severity::Remark 218 : diag::Severity::Ignored; 219 220 // -Reverything sets the state of all remarks. Note that all remarks are 221 // in remark groups, so we don't need a separate 'all remarks enabled' 222 // flag. 223 if (Opt == "everything") { 224 if (SetDiagnostic) 225 Diags.setSeverityForAll(Flavor, Severity); 226 continue; 227 } 228 229 if (Report) { 230 if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags)) 231 EmitUnknownDiagWarning(Diags, Flavor, IsPositive ? "-R" : "-Rno-", 232 Opt); 233 } else { 234 Diags.setSeverityForGroup(Flavor, Opt, 235 IsPositive ? diag::Severity::Remark 236 : diag::Severity::Ignored); 237 } 238 } 239 } 240 } 241