PR 87488: Add --with-diagnostics-urls configuration option

2020-02-15  David Malcolm  <dmalcolm@redhat.com>
	    Bernd Edlinger  <bernd.edlinger@hotmail.de>

	PR 87488
	PR other/93168
	* config.in (DIAGNOSTICS_URLS_DEFAULT): New define.
	* configure.ac (--with-diagnostics-urls): New configuration
	option, based on --with-diagnostics-color.
	(DIAGNOSTICS_URLS_DEFAULT): New define.
	* config.h: Regenerate.
	* configure: Regenerate.
	* diagnostic.c (diagnostic_urls_init): Handle -1 for
	DIAGNOSTICS_URLS_DEFAULT from configure-time
	--with-diagnostics-urls=auto-if-env by querying for a GCC_URLS
	and TERM_URLS environment variable.
	* diagnostic-url.h (diagnostic_url_format): New enum type.
	(diagnostic_urls_enabled_p): rename to...
	(determine_url_format): ... this, and change return type.
	* diagnostic-color.c (parse_env_vars_for_urls): New helper function.
	(auto_enable_urls): Disable URLs on xfce4-terminal, gnome-terminal,
	the linux console, and mingw.
	(diagnostic_urls_enabled_p): rename to...
	(determine_url_format): ... this, and adjust.
	* pretty-print.h (pretty_printer::show_urls): rename to...
	(pretty_printer::url_format): ... this, and change to enum.
	* pretty-print.c (pretty_printer::pretty_printer,
	pp_begin_url, pp_end_url, test_urls): Adjust.
	* doc/install.texi (--with-diagnostics-urls): Document the new
	configuration option.
	(--with-diagnostics-color): Document the existing interaction
	with GCC_COLORS better.
	* doc/invoke.texi (-fdiagnostics-urls): Add GCC_URLS and TERM_URLS
	vindex reference.  Update description of defaults based on the above.
	(-fdiagnostics-color): Update description of how -fdiagnostics-color
	interacts with GCC_COLORS.

11 files changed, 328 insertions, 26 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e6eb6ab4c21..22f990a3088 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,39 @@
+2020-02-15  David Malcolm  <dmalcolm@redhat.com>
+	    Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	PR 87488
+	PR other/93168
+	* config.in (DIAGNOSTICS_URLS_DEFAULT): New define.
+	* configure.ac (--with-diagnostics-urls): New configuration
+	option, based on --with-diagnostics-color.
+	(DIAGNOSTICS_URLS_DEFAULT): New define.
+	* config.h: Regenerate.
+	* configure: Regenerate.
+	* diagnostic.c (diagnostic_urls_init): Handle -1 for
+	DIAGNOSTICS_URLS_DEFAULT from configure-time
+	--with-diagnostics-urls=auto-if-env by querying for a GCC_URLS
+	and TERM_URLS environment variable.
+	* diagnostic-url.h (diagnostic_url_format): New enum type.
+	(diagnostic_urls_enabled_p): rename to...
+	(determine_url_format): ... this, and change return type.
+	* diagnostic-color.c (parse_env_vars_for_urls): New helper function.
+	(auto_enable_urls): Disable URLs on xfce4-terminal, gnome-terminal,
+	the linux console, and mingw.
+	(diagnostic_urls_enabled_p): rename to...
+	(determine_url_format): ... this, and adjust.
+	* pretty-print.h (pretty_printer::show_urls): rename to...
+	(pretty_printer::url_format): ... this, and change to enum.
+	* pretty-print.c (pretty_printer::pretty_printer,
+	pp_begin_url, pp_end_url, test_urls): Adjust.
+	* doc/install.texi (--with-diagnostics-urls): Document the new
+	configuration option.
+	(--with-diagnostics-color): Document the existing interaction
+	with GCC_COLORS better.
+	* doc/invoke.texi (-fdiagnostics-urls): Add GCC_URLS and TERM_URLS
+	vindex reference.  Update description of defaults based on the above.
+	(-fdiagnostics-color): Update description of how -fdiagnostics-color
+	interacts with GCC_COLORS.
+
 2020-02-14  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR target/93704
diff --git a/gcc/config.in b/gcc/config.in
index 48292861842..01fb18dbbb5 100644
--- a/gcc/config.in
+++ b/gcc/config.in
@@ -76,6 +76,12 @@
 #endif
 
 
+/* The default for -fdiagnostics-urls option */
+#ifndef USED_FOR_TARGET
+#undef DIAGNOSTICS_URLS_DEFAULT
+#endif
+
+
 /* Define 0/1 if static analyzer feature is enabled. */
 #ifndef USED_FOR_TARGET
 #undef ENABLE_ANALYZER
diff --git a/gcc/configure b/gcc/configure
index 5fa565a40a4..f55cdb8c77f 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -1015,6 +1015,7 @@ enable_host_shared
 enable_libquadmath_support
 with_linker_hash_style
 with_diagnostics_color
+with_diagnostics_urls
 enable_default_pie
 '
       ac_precious_vars='build_alias
@@ -1836,6 +1837,11 @@ Optional Packages:
                           auto-if-env stands for -fdiagnostics-color=auto if
                           GCC_COLOR environment variable is present and
                           -fdiagnostics-color=never otherwise
+  --with-diagnostics-urls={never,auto,auto-if-env,always}
+                          specify the default of -fdiagnostics-urls option
+                          auto-if-env stands for -fdiagnostics-urls=auto if
+                          GCC_URLS or TERM_URLS environment variable is
+                          present and -fdiagnostics-urls=never otherwise
 
 Some influential environment variables:
   CC          C compiler command
@@ -18974,7 +18980,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 18977 "configure"
+#line 18983 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19080,7 +19086,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19083 "configure"
+#line 19089 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -30575,6 +30581,37 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+# Specify what should be the default of -fdiagnostics-urls option.
+
+# Check whether --with-diagnostics-urls was given.
+if test "${with_diagnostics_urls+set}" = set; then :
+  withval=$with_diagnostics_urls; case x"$withval" in
+   xnever)
+     DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_NO
+     ;;
+   xauto)
+     DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_AUTO
+     ;;
+   xauto-if-env)
+     DIAGNOSTICS_URLS_DEFAULT=-1
+     ;;
+   xalways)
+     DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_YES
+     ;;
+   *)
+     as_fn_error $? "$withval is an invalid option to --with-diagnostics-urls" "$LINENO" 5
+     ;;
+ esac
+else
+  DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_AUTO
+fi
+
+
+cat >>confdefs.h <<_ACEOF
+#define DIAGNOSTICS_URLS_DEFAULT $DIAGNOSTICS_URLS_DEFAULT
+_ACEOF
+
+
 # Generate gcc-driver-name.h containing GCC_DRIVER_NAME for the benefit
 # of jit/jit-playback.c.
 gcc_driver_version=`eval "${get_gcc_base_ver} $srcdir/BASE-VER"`
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 671b9a67d81..0e6e475950d 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -6741,6 +6741,34 @@ AC_ARG_WITH([diagnostics-color],
 AC_DEFINE_UNQUOTED(DIAGNOSTICS_COLOR_DEFAULT, $DIAGNOSTICS_COLOR_DEFAULT,
 		   [The default for -fdiagnostics-color option])
 
+# Specify what should be the default of -fdiagnostics-urls option.
+AC_ARG_WITH([diagnostics-urls],
+[AC_HELP_STRING([--with-diagnostics-urls={never,auto,auto-if-env,always}],
+                [specify the default of -fdiagnostics-urls option
+                 auto-if-env stands for -fdiagnostics-urls=auto if
+                 GCC_URLS or TERM_URLS environment variable is present and
+                 -fdiagnostics-urls=never otherwise])],
+[case x"$withval" in
+   xnever)
+     DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_NO
+     ;;
+   xauto)
+     DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_AUTO
+     ;;
+   xauto-if-env)
+     DIAGNOSTICS_URLS_DEFAULT=-1
+     ;;
+   xalways)
+     DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_YES
+     ;;
+   *)
+     AC_MSG_ERROR([$withval is an invalid option to --with-diagnostics-urls])
+     ;;
+ esac],
+[DIAGNOSTICS_URLS_DEFAULT=DIAGNOSTICS_URL_AUTO])
+AC_DEFINE_UNQUOTED(DIAGNOSTICS_URLS_DEFAULT, $DIAGNOSTICS_URLS_DEFAULT,
+		   [The default for -fdiagnostics-urls option])
+
 # Generate gcc-driver-name.h containing GCC_DRIVER_NAME for the benefit
 # of jit/jit-playback.c.
 gcc_driver_version=`eval "${get_gcc_base_ver} $srcdir/BASE-VER"`
diff --git a/gcc/diagnostic-color.c b/gcc/diagnostic-color.c
index d5547952921..b1baded2c9e 100644
--- a/gcc/diagnostic-color.c
+++ b/gcc/diagnostic-color.c
@@ -216,6 +216,7 @@ should_colorize (void)
 	  && GetConsoleMode (h, &m);
 #else
   char const *t = getenv ("TERM");
+  /* emacs M-x shell sets TERM="dumb".  */
   return t && strcmp (t, "dumb") != 0 && isatty (STDERR_FILENO);
 #endif
 }
@@ -239,20 +240,108 @@ colorize_init (diagnostic_color_rule_t rule)
     }
 }
 
-/* Determine if URLs should be enabled, based on RULE.
+/* Return URL_FORMAT_XXX which tells how we should emit urls
+   when in always mode.
+   We use GCC_URLS and if that is not defined TERM_URLS.
+   If neither is defined the feature is enabled by default.  */
+
+static diagnostic_url_format
+parse_env_vars_for_urls ()
+{
+  const char *p;
+
+  p = getenv ("GCC_URLS"); /* Plural! */
+  if (p == NULL)
+    p = getenv ("TERM_URLS");
+
+  if (p == NULL)
+    return URL_FORMAT_DEFAULT;
+
+  if (*p == '\0')
+    return URL_FORMAT_NONE;
+
+  if (!strcmp (p, "no"))
+    return URL_FORMAT_NONE;
+
+  if (!strcmp (p, "st"))
+    return URL_FORMAT_ST;
+
+  if (!strcmp (p, "bel"))
+    return URL_FORMAT_BEL;
+
+  return URL_FORMAT_DEFAULT;
+}
+
+/* Return true if we should use urls when in auto mode, false otherwise.  */
+
+static bool
+auto_enable_urls ()
+{
+#ifdef __MINGW32__
+  return false;
+#else
+  const char *term, *colorterm;
+
+  /* First check the terminal is capable of printing color escapes,
+     if not URLs won't work either.  */
+  if (!should_colorize ())
+    return false;
+
+  /* xfce4-terminal is known to not implement URLs at this time.
+     Recently new installations (0.8) will safely ignore the URL escape
+     sequences, but a large number of legacy installations (0.6.3) print
+     garbage when URLs are printed.  Therefore we lose nothing by
+     disabling this feature for that specific terminal type.  */
+  colorterm = getenv ("COLORTERM");
+  if (colorterm && !strcmp (colorterm, "xfce4-terminal"))
+    return false;
+
+  /* Old versions of gnome-terminal where URL escapes cause screen
+     corruptions set COLORTERM="gnome-terminal", recent versions
+     with working URL support set this to "truecolor".  */
+  if (colorterm && !strcmp (colorterm, "gnome-terminal"))
+    return false;
+
+  /* Since the following checks are less specific than the ones
+     above, let GCC_URLS and TERM_URLS override the decision.  */
+  if (getenv ("GCC_URLS") || getenv ("TERM_URLS"))
+    return true;
+
+  /* In an ssh session the COLORTERM is not there, but TERM=xterm
+     can be used as an indication of a incompatible terminal while
+     TERM=xterm-256color appears to be a working terminal.  */
+  term = getenv ("TERM");
+  if (!colorterm && term && !strcmp (term, "xterm"))
+    return false;
+
+  /* When logging in a linux over serial line, we see TERM=linux
+     and no COLORTERM, it is unlikely that the URL escapes will
+     work in that environmen either.  */
+  if (!colorterm && term && !strcmp (term, "linux"))
+    return false;
+
+  return true;
+#endif
+}
+
+/* Determine if URLs should be enabled, based on RULE,
+   and, if so, which format to use.
    This reuses the logic for colorization.  */
 
-bool
-diagnostic_urls_enabled_p (diagnostic_url_rule_t rule)
+diagnostic_url_format
+determine_url_format (diagnostic_url_rule_t rule)
 {
   switch (rule)
     {
     case DIAGNOSTICS_URL_NO:
-      return false;
+      return URL_FORMAT_NONE;
     case DIAGNOSTICS_URL_YES:
-      return true;
+      return parse_env_vars_for_urls ();
     case DIAGNOSTICS_URL_AUTO:
-      return should_colorize ();
+      if (auto_enable_urls ())
+	return parse_env_vars_for_urls ();
+      else
+	return URL_FORMAT_NONE;
     default:
       gcc_unreachable ();
     }
diff --git a/gcc/diagnostic-url.h b/gcc/diagnostic-url.h
index 6be056941f1..d28460b928b 100644
--- a/gcc/diagnostic-url.h
+++ b/gcc/diagnostic-url.h
@@ -31,6 +31,22 @@ typedef enum
   DIAGNOSTICS_URL_AUTO     = 2
 } diagnostic_url_rule_t;
 
-extern bool diagnostic_urls_enabled_p (diagnostic_url_rule_t);
+/* Tells whether URLs should be emitted, and, if so, how to
+   terminate strings within the escape sequence.   */
+enum diagnostic_url_format
+{
+  /* No URLs shall be emitted.  */
+  URL_FORMAT_NONE,
+
+  /* Use ST string termination.  */
+  URL_FORMAT_ST,
+
+  /* Use BEL string termination.  */
+  URL_FORMAT_BEL
+};
+
+const diagnostic_url_format URL_FORMAT_DEFAULT = URL_FORMAT_BEL;
+
+extern diagnostic_url_format determine_url_format (diagnostic_url_rule_t);
 
 #endif /* ! GCC_DIAGNOSTIC_URL_H */
diff --git a/gcc/diagnostic.c b/gcc/diagnostic.c
index 3386f070256..e4a08f76def 100644
--- a/gcc/diagnostic.c
+++ b/gcc/diagnostic.c
@@ -260,11 +260,26 @@ diagnostic_color_init (diagnostic_context *context, int value /*= -1 */)
 void
 diagnostic_urls_init (diagnostic_context *context, int value /*= -1 */)
 {
+  /* value == -1 is the default value.  */
   if (value < 0)
-    value = DIAGNOSTICS_COLOR_DEFAULT;
+    {
+      /* If DIAGNOSTICS_URLS_DEFAULT is -1, default to
+	 -fdiagnostics-urls=auto if GCC_URLS or TERM_URLS is in the
+	 environment, otherwise default to -fdiagnostics-urls=never,
+	 for other values default to that
+	 -fdiagnostics-urls={never,auto,always}.  */
+      if (DIAGNOSTICS_URLS_DEFAULT == -1)
+	{
+	  if (!getenv ("GCC_URLS") && !getenv ("TERM_URLS"))
+	    return;
+	  value = DIAGNOSTICS_URL_AUTO;
+	}
+      else
+	value = DIAGNOSTICS_URLS_DEFAULT;
+    }
 
-  context->printer->show_urls
-    = diagnostic_urls_enabled_p ((diagnostic_url_rule_t) value);
+  context->printer->url_format
+    = determine_url_format ((diagnostic_url_rule_t) value);
 }
 
 /* Do any cleaning up required after the last diagnostic is emitted.  */
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 6ffafacff50..8ddebbb6267 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -2095,11 +2095,20 @@ GLIBC 2.11 or above, otherwise disabled.
 Tells GCC to use @var{choice} as the default for @option{-fdiagnostics-color=}
 option (if not used explicitly on the command line).  @var{choice}
 can be one of @samp{never}, @samp{auto}, @samp{always}, and @samp{auto-if-env}
-where @samp{auto} is the default.  @samp{auto-if-env} means that
-@option{-fdiagnostics-color=auto} will be the default if @code{GCC_COLORS}
-is present and non-empty in the environment, and
+where @samp{auto} is the default.  @samp{auto-if-env} makes
+@option{-fdiagnostics-color=auto} the default if @env{GCC_COLORS}
+is present and non-empty in the environment of the compiler, and
 @option{-fdiagnostics-color=never} otherwise.
 
+@item --with-diagnostics-urls=@var{choice}
+Tells GCC to use @var{choice} as the default for @option{-fdiagnostics-urls=}
+option (if not used explicitly on the command line).  @var{choice}
+can be one of @samp{never}, @samp{auto}, @samp{always}, and @samp{auto-if-env}
+where @samp{auto} is the default.  @samp{auto-if-env} makes
+@option{-fdiagnostics-urls=auto} the default if @env{GCC_URLS}
+or @env{TERM_URLS} is present and non-empty in the environment of the
+compiler, and @option{-fdiagnostics-urls=never} otherwise.
+
 @item --enable-lto
 @itemx --disable-lto
 Enable support for link-time optimization (LTO).  This is enabled by
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index bd9ecebf103..597151670be 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -3920,7 +3920,8 @@ or @samp{auto}.  The default depends on how the compiler has been configured,
 it can be any of the above @var{WHEN} options or also @samp{never}
 if @env{GCC_COLORS} environment variable isn't present in the environment,
 and @samp{auto} otherwise.
-@samp{auto} means to use color only when the standard error is a terminal.
+@samp{auto} makes GCC use color only when the standard error is a terminal,
+and when not executing in an emacs shell.
 The forms @option{-fdiagnostics-color} and @option{-fno-diagnostics-color} are
 aliases for @option{-fdiagnostics-color=always} and
 @option{-fdiagnostics-color=never}, respectively.
@@ -4033,14 +4034,46 @@ arguments in the C++ frontend.
 @item -fdiagnostics-urls[=@var{WHEN}]
 @opindex fdiagnostics-urls
 @cindex urls
+@vindex GCC_URLS @r{environment variable}
+@vindex TERM_URLS @r{environment variable}
 Use escape sequences to embed URLs in diagnostics.  For example, when
 @option{-fdiagnostics-show-option} emits text showing the command-line
 option controlling a diagnostic, embed a URL for documentation of that
 option.
 
 @var{WHEN} is @samp{never}, @samp{always}, or @samp{auto}.
-The default is @samp{auto}, which means to use URL escape sequences only
-when the standard error is a terminal.
+@samp{auto} makes GCC use URL escape sequences only when the standard error
+is a terminal, and when not executing in an emacs shell or any graphical
+terminal which is known to be incompatible with this feature, see below.
+
+The default depends on how the compiler has been configured.
+It can be any of the above @var{WHEN} options.
+
+GCC can also be configured (via the
+@option{--with-diagnostics-urls=auto-if-env} configure-time option)
+so that the default is affected by environment variables.
+Under such a configuration, GCC defaults to using @samp{auto}
+if either @env{GCC_URLS} or @env{TERM_URLS} environment variables are
+present and non-empty in the environment of the compiler, or @samp{never}
+if neither are.
+
+However, even with @option{-fdiagnostics-urls=always} the behavior is
+dependent on those environment variables:
+If @env{GCC_URLS} is set to empty or @samp{no}, do not embed URLs in
+diagnostics.  If set to @samp{st}, URLs use ST escape sequences.
+If set to @samp{bel}, the default, URLs use BEL escape sequences.
+Any other non-empty value enables the feature.
+If @env{GCC_URLS} is not set, use @env{TERM_URLS} as a fallback.
+Note: ST is an ANSI escape sequence, string terminator @samp{ESC \},
+BEL is an ASCII character, CTRL-G that usually sounds like a beep.
+
+At this time GCC tries to detect also a few terminals that are known to
+not implement the URL feature, and have bugs or at least had bugs in
+some versions that are still in use, where the URL escapes are likely
+to misbehave, i.e. print garbage on the screen.
+That list is currently xfce4-terminal, certain known to be buggy
+gnome-terminal versions, the linux console, and mingw.
+This check can be skipped with the @option{-fdiagnostics-urls=always}.
 
 @item -fno-diagnostics-show-option
 @opindex fno-diagnostics-show-option
diff --git a/gcc/pretty-print.c b/gcc/pretty-print.c
index 817c1059e08..dde138b0533 100644
--- a/gcc/pretty-print.c
+++ b/gcc/pretty-print.c
@@ -1647,7 +1647,7 @@ pretty_printer::pretty_printer (int maximum_length)
     need_newline (),
     translate_identifiers (true),
     show_color (),
-    show_urls (false)
+    url_format (URL_FORMAT_NONE)
 {
   pp_line_cutoff (this) = maximum_length;
   /* By default, we emit prefixes once per message.  */
@@ -1670,7 +1670,7 @@ pretty_printer::pretty_printer (const pretty_printer &other)
   need_newline (other.need_newline),
   translate_identifiers (other.translate_identifiers),
   show_color (other.show_color),
-  show_urls (other.show_urls)
+  url_format (other.url_format)
 {
   pp_line_cutoff (this) = maximum_length;
   /* By default, we emit prefixes once per message.  */
@@ -2171,8 +2171,19 @@ identifier_to_locale (const char *ident)
 void
 pp_begin_url (pretty_printer *pp, const char *url)
 {
-  if (pp->show_urls)
+  switch (pp->url_format)
+  {
+  case URL_FORMAT_NONE:
+    break;
+  case URL_FORMAT_ST:
+    pp_printf (pp, "\33]8;;%s\33\\", url);
+    break;
+  case URL_FORMAT_BEL:
     pp_printf (pp, "\33]8;;%s\a", url);
+    break;
+  default:
+    gcc_unreachable ();
+  }
 }
 
 /* If URL-printing is enabled, write a "close URL" escape sequence to PP.  */
@@ -2180,8 +2191,19 @@ pp_begin_url (pretty_printer *pp, const char *url)
 void
 pp_end_url (pretty_printer *pp)
 {
-  if (pp->show_urls)
+  switch (pp->url_format)
+  {
+  case URL_FORMAT_NONE:
+    break;
+  case URL_FORMAT_ST:
+    pp_string (pp, "\33]8;;\33\\");
+    break;
+  case URL_FORMAT_BEL:
     pp_string (pp, "\33]8;;\a");
+    break;
+  default:
+    gcc_unreachable ();
+  }
 }
 
 #if CHECKING_P
@@ -2490,7 +2512,7 @@ test_urls ()
 {
   {
     pretty_printer pp;
-    pp.show_urls = false;
+    pp.url_format = URL_FORMAT_NONE;
     pp_begin_url (&pp, "http://example.com");
     pp_string (&pp, "This is a link");
     pp_end_url (&pp);
@@ -2500,7 +2522,17 @@ test_urls ()
 
   {
     pretty_printer pp;
-    pp.show_urls = true;
+    pp.url_format = URL_FORMAT_ST;
+    pp_begin_url (&pp, "http://example.com");
+    pp_string (&pp, "This is a link");
+    pp_end_url (&pp);
+    ASSERT_STREQ ("\33]8;;http://example.com\33\\This is a link\33]8;;\33\\",
+		  pp_formatted_text (&pp));
+  }
+
+  {
+    pretty_printer pp;
+    pp.url_format = URL_FORMAT_BEL;
     pp_begin_url (&pp, "http://example.com");
     pp_string (&pp, "This is a link");
     pp_end_url (&pp);
diff --git a/gcc/pretty-print.h b/gcc/pretty-print.h
index 001468c966e..22892f12ab7 100644
--- a/gcc/pretty-print.h
+++ b/gcc/pretty-print.h
@@ -22,6 +22,7 @@ along with GCC; see the file COPYING3.  If not see
 #define GCC_PRETTY_PRINT_H
 
 #include "obstack.h"
+#include "diagnostic-url.h"
 
 /* Maximum number of format string arguments.  */
 #define PP_NL_ARGMAX   30
@@ -278,8 +279,8 @@ public:
   /* Nonzero means that text should be colorized.  */
   bool show_color;
 
-  /* Nonzero means that URLs should be emitted.  */
-  bool show_urls;
+  /* Whether URLs should be emitted, and which terminator to use.  */
+  diagnostic_url_format url_format;
 };
 
 static inline const char *