Warnings.cpp revision 210299 
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  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}
134