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 SmallVector<diag::kind, 10> _Diags; 77 const IntrusiveRefCntPtr< DiagnosticIDs > DiagIDs = 78 Diags.getDiagnosticIDs(); 79 // We parse the warning options twice. The first pass sets diagnostic state, 80 // while the second pass reports warnings/errors. This has the effect that 81 // we follow the more canonical "last option wins" paradigm when there are 82 // conflicting options. 83 for (unsigned Report = 0, ReportEnd = 2; Report != ReportEnd; ++Report) { 84 bool SetDiagnostic = (Report == 0); 85 86 // If we've set the diagnostic state and are not reporting diagnostics then 87 // we're done. 88 if (!SetDiagnostic && !ReportDiags) 89 break; 90 91 for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) { 92 const auto Flavor = diag::Flavor::WarningOrError; 93 StringRef Opt = Opts.Warnings[i]; 94 StringRef OrigOpt = Opts.Warnings[i]; 95 96 // Treat -Wformat=0 as an alias for -Wno-format. 97 if (Opt == "format=0") 98 Opt = "no-format"; 99 100 // Check to see if this warning starts with "no-", if so, this is a 101 // negative form of the option. 102 bool isPositive = !Opt.consume_front("no-"); 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::Severity Mapping = 107 isPositive ? diag::Severity::Warning : diag::Severity::Ignored; 108 109 // -Wsystem-headers is a special case, not driven by the option table. It 110 // cannot be controlled with -Werror. 111 if (Opt == "system-headers") { 112 if (SetDiagnostic) 113 Diags.setSuppressSystemWarnings(!isPositive); 114 continue; 115 } 116 117 // -Weverything is a special case as well. It implicitly enables all 118 // warnings, including ones not explicitly in a warning group. 119 if (Opt == "everything") { 120 if (SetDiagnostic) { 121 if (isPositive) { 122 Diags.setEnableAllWarnings(true); 123 } else { 124 Diags.setEnableAllWarnings(false); 125 Diags.setSeverityForAll(Flavor, diag::Severity::Ignored); 126 } 127 } 128 continue; 129 } 130 131 // -Werror/-Wno-error is a special case, not controlled by the option 132 // table. It also has the "specifier" form of -Werror=foo. GCC supports 133 // the deprecated -Werror-implicit-function-declaration which is used by 134 // a few projects. 135 if (Opt.starts_with("error")) { 136 StringRef Specifier; 137 if (Opt.size() > 5) { // Specifier must be present. 138 if (Opt[5] != '=' && 139 Opt.substr(5) != "-implicit-function-declaration") { 140 if (Report) 141 Diags.Report(diag::warn_unknown_warning_specifier) 142 << "-Werror" << ("-W" + OrigOpt.str()); 143 continue; 144 } 145 Specifier = Opt.substr(6); 146 } 147 148 if (Specifier.empty()) { 149 if (SetDiagnostic) 150 Diags.setWarningsAsErrors(isPositive); 151 continue; 152 } 153 154 if (SetDiagnostic) { 155 // Set the warning as error flag for this specifier. 156 Diags.setDiagnosticGroupWarningAsError(Specifier, isPositive); 157 } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) { 158 EmitUnknownDiagWarning(Diags, Flavor, "-Werror=", Specifier); 159 } 160 continue; 161 } 162 163 // -Wfatal-errors is yet another special case. 164 if (Opt.starts_with("fatal-errors")) { 165 StringRef Specifier; 166 if (Opt.size() != 12) { 167 if ((Opt[12] != '=' && Opt[12] != '-') || Opt.size() == 13) { 168 if (Report) 169 Diags.Report(diag::warn_unknown_warning_specifier) 170 << "-Wfatal-errors" << ("-W" + OrigOpt.str()); 171 continue; 172 } 173 Specifier = Opt.substr(13); 174 } 175 176 if (Specifier.empty()) { 177 if (SetDiagnostic) 178 Diags.setErrorsAsFatal(isPositive); 179 continue; 180 } 181 182 if (SetDiagnostic) { 183 // Set the error as fatal flag for this specifier. 184 Diags.setDiagnosticGroupErrorAsFatal(Specifier, isPositive); 185 } else if (DiagIDs->getDiagnosticsInGroup(Flavor, Specifier, _Diags)) { 186 EmitUnknownDiagWarning(Diags, Flavor, "-Wfatal-errors=", Specifier); 187 } 188 continue; 189 } 190 191 if (Report) { 192 if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags)) 193 EmitUnknownDiagWarning(Diags, Flavor, isPositive ? "-W" : "-Wno-", 194 Opt); 195 } else { 196 Diags.setSeverityForGroup(Flavor, Opt, Mapping); 197 } 198 } 199 200 for (StringRef Opt : Opts.Remarks) { 201 const auto Flavor = diag::Flavor::Remark; 202 203 // Check to see if this warning starts with "no-", if so, this is a 204 // negative form of the option. 205 bool IsPositive = !Opt.consume_front("no-"); 206 207 auto Severity = IsPositive ? diag::Severity::Remark 208 : diag::Severity::Ignored; 209 210 // -Reverything sets the state of all remarks. Note that all remarks are 211 // in remark groups, so we don't need a separate 'all remarks enabled' 212 // flag. 213 if (Opt == "everything") { 214 if (SetDiagnostic) 215 Diags.setSeverityForAll(Flavor, Severity); 216 continue; 217 } 218 219 if (Report) { 220 if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags)) 221 EmitUnknownDiagWarning(Diags, Flavor, IsPositive ? "-R" : "-Rno-", 222 Opt); 223 } else { 224 Diags.setSeverityForGroup(Flavor, Opt, 225 IsPositive ? diag::Severity::Remark 226 : diag::Severity::Ignored); 227 } 228 } 229 } 230 231 // Process suppression mappings file after processing other warning flags 232 // (like -Wno-unknown-warning-option) as we can emit extra warnings during 233 // processing. 234 if (!Opts.DiagnosticSuppressionMappingsFile.empty()) { 235 if (auto FileContents = 236 VFS.getBufferForFile(Opts.DiagnosticSuppressionMappingsFile)) { 237 Diags.setDiagSuppressionMapping(**FileContents); 238 } else if (ReportDiags) { 239 Diags.Report(diag::err_drv_no_such_file) 240 << Opts.DiagnosticSuppressionMappingsFile; 241 } 242 } 243 } 244