Warnings.cpp revision 194711 
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 and
17// -Werror.
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
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/FrontendDiagnostic.h"
28#include <cstdio>
29#include <cstring>
30#include <utility>
31#include <algorithm>
32using namespace clang;
33
34bool clang::ProcessWarningOptions(Diagnostic &Diags,
35                                  std::vector<std::string> &Warnings,
36                                  bool Pedantic, bool PedanticErrors,
37                                  bool NoWarnings) {
38  Diags.setSuppressSystemWarnings(true);  // Default to -Wno-system-headers
39  Diags.setIgnoreAllWarnings(NoWarnings);
40
41  // If -pedantic or -pedantic-errors was specified, then we want to map all
42  // extension diagnostics onto WARNING or ERROR unless the user has futz'd
43  // around with them explicitly.
44  if (PedanticErrors)
45    Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Error);
46  else if (Pedantic)
47    Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Warn);
48  else
49    Diags.setExtensionHandlingBehavior(Diagnostic::Ext_Ignore);
50
51  // FIXME: -Wfatal-errors / -Wfatal-errors=foo
52
53  for (unsigned i = 0, e = Warnings.size(); i != e; ++i) {
54    const std::string &Opt = Warnings[i];
55    const char *OptStart = &Opt[0];
56    const char *OptEnd = OptStart+Opt.size();
57    assert(*OptEnd == 0 && "Expect null termination for lower-bound search");
58
59    // Check to see if this warning starts with "no-", if so, this is a negative
60    // form of the option.
61    bool isPositive = true;
62    if (OptEnd-OptStart > 3 && memcmp(OptStart, "no-", 3) == 0) {
63      isPositive = false;
64      OptStart += 3;
65    }
66
67    // Figure out how this option affects the warning.  If -Wfoo, map the
68    // diagnostic to a warning, if -Wno-foo, map it to ignore.
69    diag::Mapping Mapping = isPositive ? diag::MAP_WARNING : diag::MAP_IGNORE;
70
71    // -Wsystem-headers is a special case, not driven by the option table.  It
72    // cannot be controlled with -Werror.
73    if (OptEnd-OptStart == 14 && memcmp(OptStart, "system-headers", 14) == 0) {
74      Diags.setSuppressSystemWarnings(!isPositive);
75      continue;
76    }
77
78    // -Werror/-Wno-error is a special case, not controlled by the option table.
79    // It also has the "specifier" form of -Werror=foo and -Werror-foo.
80    if (OptEnd-OptStart >= 5 && memcmp(OptStart, "error", 5) == 0) {
81      const char *Specifier = 0;
82      if (OptEnd-OptStart != 5) {  // Specifier must be present.
83        if ((OptStart[5] != '=' && OptStart[5] != '-') ||
84            OptEnd-OptStart == 6) {
85          fprintf(stderr, "warning: unknown -Werror warning specifier: -W%s\n",
86                  Opt.c_str());
87          continue;
88        }
89        Specifier = OptStart+6;
90      }
91
92      if (Specifier == 0) {
93        Diags.setWarningsAsErrors(true);
94        continue;
95      }
96
97      // -Werror=foo maps foo to Error, -Wno-error=foo maps it to Warning.
98      Mapping = isPositive ? diag::MAP_ERROR : diag::MAP_WARNING_NO_WERROR;
99      OptStart = Specifier;
100    }
101
102    if (Diags.setDiagnosticGroupMapping(OptStart, Mapping))
103      Diags.Report(FullSourceLoc(), diag::warn_unknown_warning_option)
104        << ("-W" + Opt);
105  }
106
107  return false;
108}
109