Warnings.cpp revision 208954 
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>
32using namespace clang;
33
34void clang::ProcessWarningOptions(Diagnostic &Diags,
35                                  const DiagnosticOptions &Opts) {
36  Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
37  Diags.setIgnoreAllWarnings(Opts.IgnoreWarnings);
38
39  // Handle -ferror-limit
40  if (Opts.ErrorLimit)
41    Diags.setErrorLimit(Opts.ErrorLimit);
42  if (Opts.TemplateBacktraceLimit)
43    Diags.setTemplateBacktraceLimit(Opts.TemplateBacktraceLimit);
44
45  // If -pedantic or -pedantic-errors was specified, then we want to map all
46  // extension diagnostics onto WARNING or ERROR unless the user has futz'd
47  // around with them explicitly.
48  if (Opts.PedanticErrors)
49    Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Error);
50  else if (Opts.Pedantic)
51    Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Warn);
52  else
53    Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Ignore);
54
55  for (unsigned i = 0, e = Opts.Warnings.size(); i != e; ++i) {
56    const std::string &Opt = Opts.Warnings[i];
57    const char *OptStart = &Opt[0];
58    const char *OptEnd = OptStart+Opt.size();
59    assert(*OptEnd == 0 && "Expect null termination for lower-bound search");
60
61    // Check to see if this warning starts with "no-", if so, this is a negative
62    // form of the option.
63    bool isPositive = true;
64    if (OptEnd-OptStart > 3 && memcmp(OptStart, "no-", 3) == 0) {
65      isPositive = false;
66      OptStart += 3;
67    }
68
69    // Figure out how this option affects the warning.  If -Wfoo, map the
70    // diagnostic to a warning, if -Wno-foo, map it to ignore.
71    diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
72
73    // -Wsystem-headers is a special case, not driven by the option table.  It
74    // cannot be controlled with -Werror.
75    if (OptEnd-OptStart == 14 && memcmp(OptStart, "system-headers", 14) == 0) {
76      Diags.setSuppressSystemWarnings(!isPositive);
77      continue;
78    }
79
80    // -Werror/-Wno-error is a special case, not controlled by the option table.
81    // It also has the "specifier" form of -Werror=foo and -Werror-foo.
82    if (OptEnd-OptStart >= 5 && memcmp(OptStart, "error", 5) == 0) {
83      const char *Specifier = 0;
84      if (OptEnd-OptStart != 5) {  // Specifier must be present.
85        if ((OptStart[5] != '=' && OptStart[5] != '-') ||
86            OptEnd-OptStart == 6) {
87          Diags.Report(diag::warn_unknown_warning_specifier)
88            << "-Werror" << ("-W" + Opt);
89          continue;
90        }
91        Specifier = OptStart+6;
92      }
93
94      if (Specifier == 0) {
95        Diags.setWarningsAsErrors(isPositive);
96        continue;
97      }
98
99      // -Werror=foo maps foo to Error, -Wno-error=foo maps it to Warning.
100      Mapping = isPositive ? diag::MAP_ERROR : diag::MAP_WARNING_NO_WERROR;
101      OptStart = Specifier;
102    }
103
104    // -Wfatal-errors is yet another special case.
105    if (OptEnd-OptStart >= 12 && memcmp(OptStart, "fatal-errors", 12) == 0) {
106      const char* Specifier = 0;
107      if (OptEnd-OptStart != 12) {
108        if ((OptStart[12] != '=' && OptStart[12] != '-') ||
109            OptEnd-OptStart == 13) {
110          Diags.Report(diag::warn_unknown_warning_specifier)
111            << "-Wfatal-errors" << ("-W" + Opt);
112          continue;
113        }
114        Specifier = OptStart + 13;
115      }
116
117      if (Specifier == 0) {
118        Diags.setErrorsAsFatal(isPositive);
119        continue;
120      }
121
122      // -Wfatal-errors=foo maps foo to Fatal, -Wno-fatal-errors=foo
123      // maps it to Error.
124      Mapping = isPositive ? diag::MAP_FATAL : diag::MAP_ERROR_NO_WFATAL;
125      OptStart = Specifier;
126    }
127
128    if (Diags.setDiagnosticGroupMapping(OptStart, Mapping))
129      Diags.Report(diag::warn_unknown_warning_option) << ("-W" + Opt);
130  }
131}
132