pretty-print: support URL escape sequences (PR 87488)

https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda
describes an emerging standard for embedding URLs in escape sequences
for marking up text output.  This is supported e.g. by recent releases
of GNOME Terminal.

This patch adds support to our pretty-printing framework for emitting
URLs.

A followup patch uses this to add URLs to the pertinent documentation
for the output of -fdiagnostics-show-option.

gcc/ChangeLog:
	PR 87488
	* common.opt (fdiagnostics-urls=): New option.
	(diagnostic-url.h): Add SourceInclude.
	(diagnostic_url_rule): New enum.
	* diagnostic-color.c: Include "diagnostic-url.h".
	(diagnostic_urls_enabled_p): New function.
	* diagnostic-url.h: New file.
	* diagnostic.c: Include "diagnostic-url.h".
	(diagnostic_urls_init): New function.
	* diagnostic.h (diagnostic_urls_init): New decl.
	* doc/invoke.texi (Diagnostic Message Formatting Options): Add
	-fdiagnostics-urls to the list.
	(-fdiagnostics-urls): New option.
	* gcc.c (driver_handle_option): Handle OPT_fdiagnostics_urls_.
	(driver::global_initializations): Call diagnostic_urls_init.
	* opts-global.c (init_options_once): Likewise.
	* opts.c (common_handle_option): Handle OPT_fdiagnostics_urls_.
	* pretty-print.c (pretty_printer::pretty_printer): Initialize
	show_urls.
	(pp_begin_url): New function.
	(pp_end_url): New function.
	(selftest::test_urls): New selftest.
	(selftest::pretty_print_c_tests): Call it.
	* pretty-print.h (pretty_printer::show_urls): New field.
	(pp_begin_url): New decl.
	(pp_end_url): New decl.

gcc/testsuite/ChangeLog:
	PR 87488
	* lib/prune.exp (TEST_ALWAYS_FLAGS): Add -fdiagnostics-urls=never.

From-SVN: r276841

1 files changed, 36 insertions, 0 deletions

diff --git a/gcc/diagnostic-url.h b/gcc/diagnostic-url.h
new file mode 100644
index 00000000000..ce0de459f32
--- /dev/null
+++ b/gcc/diagnostic-url.h
@@ -0,0 +1,36 @@
+/* Copyright (C) 2019 Free Software Foundation, Inc.
+   Contributed by David Malcolm <dmalcolm@redhat.com>.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_DIAGNOSTIC_URL_H
+#define GCC_DIAGNOSTIC_URL_H
+
+/* Whether to add URLs to diagnostics:
+   - DIAGNOSTICS_URL_NO: never
+   - DIAGNOSTICS_URL_YES: always
+   - DIAGNOSTICS_URL_AUTO: depending on the output stream.  */
+typedef enum
+{
+  DIAGNOSTICS_URL_NO       = 0,
+  DIAGNOSTICS_URL_YES      = 1,
+  DIAGNOSTICS_URL_AUTO     = 2
+} diagnostic_url_rule_t;
+
+extern bool diagnostic_urls_enabled_p (diagnostic_url_rule_t);
+
+#endif /* ! GCC_DIAGNOSTIC_URL_H */