244 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// Command line warning options handler.10//11//===----------------------------------------------------------------------===//12//13// This file is responsible for handling all warning options. This includes14// 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=foo21//22// Remark options are also handled here, analogously, except that they are much23// 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>32using namespace clang;33 34// EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning35// opts36static 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 46void clang::ProcessWarningOptions(DiagnosticsEngine &Diags,47 const DiagnosticOptions &Opts,48 llvm::vfs::FileSystem &VFS,49 bool ReportDiags) {50 Diags.setSuppressSystemWarnings(true); // Default to -Wno-system-headers51 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-limit59 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 all67 // extension diagnostics onto WARNING or ERROR unless the user has futz'd68 // 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 else74 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 that81 // we follow the more canonical "last option wins" paradigm when there are82 // 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 then87 // 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 a101 // 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 the105 // 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. It110 // 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 all118 // 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 option132 // table. It also has the "specifier" form of -Werror=foo. GCC supports133 // the deprecated -Werror-implicit-function-declaration which is used by134 // 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 a204 // negative form of the option.205 bool IsPositive = !Opt.consume_front("no-");206 207 auto Severity = IsPositive ? diag::Severity::Remark208 : diag::Severity::Ignored;209 210 // -Reverything sets the state of all remarks. Note that all remarks are211 // 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::Remark226 : diag::Severity::Ignored);227 }228 }229 }230 231 // Process suppression mappings file after processing other warning flags232 // (like -Wno-unknown-warning-option) as we can emit extra warnings during233 // 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