gcc/go/gofrontend/go-diagnostics.cc

   1 // go-diagnostics.cc -- Go error/warning diagnostics utilities.
   2
   3 // Copyright 2016 The Go Authors. All rights reserved.
   4 // Use of this source code is governed by a BSD-style
   5 // license that can be found in the LICENSE file.
   6
   7 #include "go-diagnostics.h"
   8
   9 static std::string
  10 mformat_value()
  11 {
  12   return std::string(xstrerror(errno));
  13 }
  14
  15 // Rewrite a format string to expand any extensions not
  16 // supported by sprintf(). See comments in go-diagnostics.h
  17 // for list of supported format specifiers.
  18
  19 static std::string
  20 expand_format(const char* fmt)
  21 {
  22   std::stringstream ss;
  23   for (const char* c = fmt; *c; ++c)
  24     {
  25       if (*c != '%')
  26         {
  27           ss << *c;
  28           continue;
  29         }
  30       c++;
  31       switch (*c)
  32         {
  33           case '\0':
  34             {
  35               // malformed format string
  36               go_unreachable();
  37             }
  38           case '%':
  39             {
  40               ss << "%";
  41               break;
  42             }
  43           case 'm':
  44             {
  45               ss << mformat_value();
  46               break;
  47             }
  48           case '<':
  49             {
  50               ss << go_open_quote();
  51               break;
  52             }
  53           case '>':
  54             {
  55               ss << go_close_quote();
  56               break;
  57             }
  58           case 'q':
  59             {
  60               ss << go_open_quote();
  61               c++;
  62               if (*c == 'm')
  63                 {
  64                   ss << mformat_value();
  65                 }
  66               else
  67                 {
  68                   ss << "%" << *c;
  69                 }
  70               ss << go_close_quote();
  71               break;
  72             }
  73           default:
  74             {
  75               ss << "%" << *c;
  76             }
  77         }
  78     }
  79   return ss.str();
  80 }
  81
  82 // Expand message format specifiers, using a combination of
  83 // expand_format above to handle extensions (ex: %m, %q) and vasprintf()
  84 // to handle regular printf-style formatting. A pragma is being used here to
  85 // suppress this warning:
  86 //
  87 //   warning: function ‘std::__cxx11::string expand_message(const char*, __va_list_tag*)’ might be a candidate for ‘gnu_printf’ format attribute [-Wsuggest-attribute=format]
  88 //
  89 // What appears to be happening here is that the checker is deciding that
  90 // because of the call to vasprintf() (which has attribute gnu_printf), the
  91 // calling function must need to have attribute gnu_printf as well, even
  92 // though there is already an attribute declaration for it.
  93
  94 static std::string
  95 expand_message(const char* fmt, va_list ap) GO_ATTRIBUTE_GCC_DIAG(1,0);
  96
  97 #pragma GCC diagnostic push
  98 #pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
  99
 100 static std::string
 101 expand_message(const char* fmt, va_list ap)
 102 {
 103   char* mbuf = 0;
 104   std::string expanded_fmt = expand_format(fmt);
 105   int nwr = vasprintf(&mbuf, expanded_fmt.c_str(), ap);
 106   if (nwr == -1)
 107     {
 108       // memory allocation failed
 109       go_be_error_at(Linemap::unknown_location(),
 110                      "memory allocation failed in vasprintf");
 111       go_assert(0);
 112     }
 113   std::string rval = std::string(mbuf);
 114   free(mbuf);
 115   return rval;
 116 }
 117
 118 #pragma GCC diagnostic pop
 119
 120 static const char* cached_open_quote = NULL;
 121 static const char* cached_close_quote = NULL;
 122
 123 const char*
 124 go_open_quote()
 125 {
 126   if (cached_open_quote == NULL)
 127     go_be_get_quotechars(&cached_open_quote, &cached_close_quote);
 128   return cached_open_quote;
 129 }
 130
 131 const char*
 132 go_close_quote()
 133 {
 134   if (cached_close_quote == NULL)
 135     go_be_get_quotechars(&cached_open_quote, &cached_close_quote);
 136   return cached_close_quote;
 137 }
 138
 139 void
 140 go_error_at(const Location location, const char* fmt, ...)
 141 {
 142   va_list ap;
 143
 144   va_start(ap, fmt);
 145   go_be_error_at(location, expand_message(fmt, ap));
 146   va_end(ap);
 147 }
 148
 149 void
 150 go_warning_at(const Location location, int opt, const char* fmt, ...)
 151 {
 152   va_list ap;
 153
 154   va_start(ap, fmt);
 155   go_be_warning_at(location, opt, expand_message(fmt, ap));
 156   va_end(ap);
 157 }
 158
 159 void
 160 go_fatal_error(const Location location, const char* fmt, ...)
 161 {
 162   va_list ap;
 163
 164   va_start(ap, fmt);
 165   go_be_fatal_error(location, expand_message(fmt, ap));
 166   va_end(ap);
 167 }
 168
 169 void
 170 go_inform(const Location location, const char* fmt, ...)
 171 {
 172   va_list ap;
 173
 174   va_start(ap, fmt);
 175   go_be_inform(location, expand_message(fmt, ap));
 176   va_end(ap);
 177 }