lib/Frontend/Warnings.cpp

   1 //===--- Warnings.cpp - C-Language Front-end ------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // Command line warning options handler.
  11 //
  12 //===----------------------------------------------------------------------===//
  13 //
  14 // This file is responsible for handling all warning options. This includes
  15 // a number of -Wfoo options and their variants, which are driven by TableGen-
  16 // generated data, and the special cases -pedantic, -pedantic-errors, -w,
  17 // -Werror and -Wfatal-errors.
  18 //
  19 // Each warning option controls any number of actual warnings.
  20 // Given a warning option 'foo', the following are valid:
  21 //    -Wfoo, -Wno-foo, -Werror=foo, -Wfatal-errors=foo
  22 //
  23 #include "clang/Frontend/Utils.h"
  24 #include "clang/Basic/Diagnostic.h"
  25 #include "clang/Sema/SemaDiagnostic.h"
  26 #include "clang/Lex/LexDiagnostic.h"
  27 #include "clang/Frontend/DiagnosticOptions.h"
  28 #include "clang/Frontend/FrontendDiagnostic.h"
  29 #include <cstring>
  30 #include <utility>
  31 #include <algorithm>
  32 using namespace clang;
  33
  34 void clang::ProcessWarningOptions(Diagnostic &Diags,
  35                                   const DiagnosticOptions &Opts) {
  36   Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
  37   Diags.setIgnoreAllWarnings(Opts.IgnoreWarnings);
  38   Diags.setShowOverloads(
  39     static_cast<Diagnostic::OverloadsShown>(Opts.ShowOverloads));
  40
  41   // Handle -ferror-limit
  42   if (Opts.ErrorLimit)
  43     Diags.setErrorLimit(Opts.ErrorLimit);
  44   if (Opts.TemplateBacktraceLimit)
  45     Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
  46
  47   // If -pedantic or -pedantic-errors was specified, then we want to map all
  48   // extension diagnostics onto WARNING or ERROR unless the user has futz'd
  49   // around with them explicitly.
  50   if (Opts.PedanticErrors)
  51     Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Error);
  52   else if (Opts.Pedantic)
  53     Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Warn);
  54   else
  55     Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Ignore);
  56
  57   for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
  58     const std::string &Opt = Opts.Warnings[i];
  59     const char *OptStart = &Opt[0];
  60     const char *OptEnd = OptStart+Opt.size();
  61     assert(*OptEnd == 0 && "Expect null termination for lower-bound search");
  62
  63     // Check to see if this warning starts with "no-", if so, this is a negative
  64     // form of the option.
  65     bool isPositive = true;
  66     if (OptEnd-OptStart > 3 && memcmp(OptStart, "no-", 3) == 0) {
  67       isPositive = false;
  68       OptStart += 3;
  69     }
  70
  71     // Figure out how this option affects the warning.  If -Wfoo, map the
  72     // diagnostic to a warning, if -Wno-foo, map it to ignore.
  73     diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
  74
  75     // -Wsystem-headers is a special case, not driven by the option table.  It
  76     // cannot be controlled with -Werror.
  77     if (OptEnd-OptStart == 14 && memcmp(OptStart, "system-headers", 14) == 0) {
  78       Diags.setSuppressSystemWarnings(!isPositive);
  79       continue;
  80     }
  81
  82     // -Werror/-Wno-error is a special case, not controlled by the option table.
  83     // It also has the "specifier" form of -Werror=foo and -Werror-foo.
  84     if (OptEnd-OptStart >= 5 && memcmp(OptStart, "error", 5) == 0) {
  85       const char *Specifier = 0;
  86       if (OptEnd-OptStart != 5) {  // Specifier must be present.
  87         if ((OptStart[5] != '=' && OptStart[5] != '-') ||
  88             OptEnd-OptStart == 6) {
  89           Diags.Report(diag::warn_unknown_warning_specifier)
  90             << "-Werror" << ("-W" + Opt);
  91           continue;
  92         }
  93         Specifier = OptStart+6;
  94       }
  95
  96       if (Specifier == 0) {
  97         Diags.setWarningsAsErrors(isPositive);
  98         continue;
  99       }
 100
 101       // -Werror=foo maps foo to Error, -Wno-error=foo maps it to Warning.
 102       Mapping = isPositive ? diag::MAP_ERROR : diag::MAP_WARNING_NO_WERROR;
 103       OptStart = Specifier;
 104     }
 105
 106     // -Wfatal-errors is yet another special case.
 107     if (OptEnd-OptStart >= 12 && memcmp(OptStart, "fatal-errors", 12) == 0) {
 108       const char* Specifier = 0;
 109       if (OptEnd-OptStart != 12) {
 110         if ((OptStart[12] != '=' && OptStart[12] != '-') ||
 111             OptEnd-OptStart == 13) {
 112           Diags.Report(diag::warn_unknown_warning_specifier)
 113             << "-Wfatal-errors" << ("-W" + Opt);
 114           continue;
 115         }
 116         Specifier = OptStart + 13;
 117       }
 118
 119       if (Specifier == 0) {
 120         Diags.setErrorsAsFatal(isPositive);
 121         continue;
 122       }
 123
 124       // -Wfatal-errors=foo maps foo to Fatal, -Wno-fatal-errors=foo
 125       // maps it to Error.
 126       Mapping = isPositive ? diag::MAP_FATAL : diag::MAP_ERROR_NO_WFATAL;
 127       OptStart = Specifier;
 128     }
 129
 130     if (Diags.setDiagnosticGroupMapping(OptStart, Mapping))
 131       Diags.Report(diag::warn_unknown_warning_option) << ("-W" + Opt);
 132   }
 133 }