Machine-readable diagnostic output (PR other/19165)

This patch implements a -fdiagnostics-format=json option which
converts the diagnostics to be output to stderr in a JSON format;
see the documentation in invoke.texi.

Logically-related diagnostics are nested at the JSON level, using
the auto_diagnostic_group mechanism.

gcc/ChangeLog:
	PR other/19165
	* Makefile.in (OBJS): Move json.o to...
	(OBJS-libcommon): ...here and add diagnostic-format-json.o.
	* common.opt (fdiagnostics-format=): New option.
	(diagnostics_output_format): New enum.
	* diagnostic-format-json.cc: New file.
	* diagnostic.c (default_diagnostic_final_cb): New function, taken
	from start of diagnostic_finish.
	(diagnostic_initialize): Initialize final_cb to
	default_diagnostic_final_cb.
	(diagnostic_finish): Move "being treated as errors" messages to
	default_diagnostic_final_cb.  Call any final_cb.
	(default_diagnostic_finalizer): Add diagnostic_t param.
	(diagnostic_report_diagnostic): Pass "orig_diag_kind" to
	diagnostic_finalizer callback.
	* diagnostic.h (enum diagnostics_output_format): New enum.
	(diagnostic_finalizer_fn): Reimplement, adding diagnostic_t param.
	(struct diagnostic_context): Add "final_cb".
	(default_diagnostic_finalizer): Add diagnostic_t param.
	(diagnostic_output_format_init): New decl.
	* doc/invoke.texi (-fdiagnostics-format): New option.
	* dwarf2out.c (gen_producer_string): Ignore
	OPT_fdiagnostics_format_.
	* gcc.c (driver_handle_option): Handle OPT_fdiagnostics_format_.
	* lto-wrapper.c (append_diag_options): Ignore it.
	* opts.c (common_handle_option): Handle it.

gcc/c-family/ChangeLog:
	PR other/19165
	* c-opts.c (c_diagnostic_finalizer): Add diagnostic_t param.

gcc/fortran/ChangeLog:
	PR other/19165
	* error.c (gfc_diagnostic_finalizer): Add diagnostic_t param.

gcc/jit/ChangeLog:
	PR other/19165
	* dummy-frontend.c (jit_begin_diagnostic): Add diagnostic_t param.

gcc/testsuite/ChangeLog:
	PR other/19165
	* c-c++-common/diagnostic-format-json-1.c: New test.
	* c-c++-common/diagnostic-format-json-2.c: New test.
	* c-c++-common/diagnostic-format-json-3.c: New test.
	* c-c++-common/diagnostic-format-json-4.c: New test.
	* c-c++-common/diagnostic-format-json-5.c: New test.
	* gcc.dg/plugin/diagnostic_plugin_test_show_locus.c
	(custom_diagnostic_finalizer): Add diagnostic_t param.
	* gcc.dg/plugin/location_overflow_plugin.c
	(verify_unpacked_ranges): Likewise.
	(verify_no_columns): Likewise.
	* gfortran.dg/diagnostic-format-json-1.F90: New test.
	* gfortran.dg/diagnostic-format-json-2.F90: New test.
	* gfortran.dg/diagnostic-format-json-3.F90: New test.

From-SVN: r266186

1 files changed, 264 insertions, 0 deletions

diff --git a/gcc/diagnostic-format-json.cc b/gcc/diagnostic-format-json.cc
new file mode 100644
index 0000000..8d56120
--- /dev/null
+++ b/gcc/diagnostic-format-json.cc
@@ -0,0 +1,264 @@
+/* JSON output for diagnostics
+   Copyright (C) 2018 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/>.  */
+
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "diagnostic.h"
+#include "json.h"
+
+/* The top-level JSON array of pending diagnostics.  */
+
+static json::array *toplevel_array;
+
+/* The JSON object for the current diagnostic group.  */
+
+static json::object *cur_group;
+
+/* The JSON array for the "children" array within the current diagnostic
+   group.  */
+
+static json::array *cur_children_array;
+
+/* Generate a JSON object for LOC.  */
+
+static json::object *
+json_from_expanded_location (location_t loc)
+{
+  expanded_location exploc = expand_location (loc);
+  json::object *result = new json::object ();
+  result->set ("file", new json::string (exploc.file));
+  result->set ("line", new json::number (exploc.line));
+  result->set ("column", new json::number (exploc.column));
+  return result;
+}
+
+/* Generate a JSON object for LOC_RANGE.  */
+
+static json::object *
+json_from_location_range (const location_range *loc_range, unsigned range_idx)
+{
+  location_t caret_loc = get_pure_location (loc_range->m_loc);
+
+  if (caret_loc == UNKNOWN_LOCATION)
+    return NULL;
+
+  location_t start_loc = get_start (loc_range->m_loc);
+  location_t finish_loc = get_finish (loc_range->m_loc);
+
+  json::object *result = new json::object ();
+  result->set ("caret", json_from_expanded_location (caret_loc));
+  if (start_loc != caret_loc)
+    result->set ("start", json_from_expanded_location (start_loc));
+  if (finish_loc != caret_loc)
+    result->set ("finish", json_from_expanded_location (finish_loc));
+
+  if (loc_range->m_label)
+    {
+      label_text text;
+      text = loc_range->m_label->get_text (range_idx);
+      if (text.m_buffer)
+	result->set ("label", new json::string (text.m_buffer));
+      text.maybe_free ();
+    }
+
+  return result;
+}
+
+/* Generate a JSON object for HINT.  */
+
+static json::object *
+json_from_fixit_hint (const fixit_hint *hint)
+{
+  json::object *fixit_obj = new json::object ();
+
+  location_t start_loc = hint->get_start_loc ();
+  fixit_obj->set ("start", json_from_expanded_location (start_loc));
+  location_t next_loc = hint->get_next_loc ();
+  fixit_obj->set ("next", json_from_expanded_location (next_loc));
+  fixit_obj->set ("string", new json::string (hint->get_string ()));
+
+  return fixit_obj;
+}
+
+/* No-op implementation of "begin_diagnostic" for JSON output.  */
+
+static void
+json_begin_diagnostic (diagnostic_context *, diagnostic_info *)
+{
+}
+
+/* Implementation of "end_diagnostic" for JSON output.
+   Generate a JSON object for DIAGNOSTIC, and store for output
+   within current diagnostic group.  */
+
+static void
+json_end_diagnostic (diagnostic_context *context, diagnostic_info *diagnostic,
+		     diagnostic_t orig_diag_kind)
+{
+  json::object *diag_obj = new json::object ();
+
+  /* Get "kind" of diagnostic.  */
+  {
+    static const char *const diagnostic_kind_text[] = {
+#define DEFINE_DIAGNOSTIC_KIND(K, T, C) (T),
+#include "diagnostic.def"
+#undef DEFINE_DIAGNOSTIC_KIND
+      "must-not-happen"
+    };
+    /* Lose the trailing ": ".  */
+    const char *kind_text = diagnostic_kind_text[diagnostic->kind];
+    size_t len = strlen (kind_text);
+    gcc_assert (len > 2);
+    gcc_assert (kind_text[len - 2] == ':');
+    gcc_assert (kind_text[len - 1] == ' ');
+    char *rstrip = xstrdup (kind_text);
+    rstrip[len - 2] = '\0';
+    diag_obj->set ("kind", new json::string (rstrip));
+    free (rstrip);
+  }
+
+  // FIXME: encoding of the message (json::string requires UTF-8)
+  diag_obj->set ("message",
+		 new json::string (pp_formatted_text (context->printer)));
+  pp_clear_output_area (context->printer);
+
+  char *option_text;
+  option_text = context->option_name (context, diagnostic->option_index,
+				      orig_diag_kind, diagnostic->kind);
+  if (option_text)
+    {
+      diag_obj->set ("option", new json::string (option_text));
+      free (option_text);
+    }
+
+  /* If we've already emitted a diagnostic within this auto_diagnostic_group,
+     then add diag_obj to its "children" array.  */
+  if (cur_group)
+    {
+      gcc_assert (cur_children_array);
+      cur_children_array->append (diag_obj);
+    }
+  else
+    {
+      /* Otherwise, make diag_obj be the top-level object within the group;
+	 add a "children" array.  */
+      toplevel_array->append (diag_obj);
+      cur_group = diag_obj;
+      cur_children_array = new json::array ();
+      diag_obj->set ("children", cur_children_array);
+    }
+
+  const rich_location *richloc = diagnostic->richloc;
+
+  json::array *loc_array = new json::array ();
+  diag_obj->set ("locations", loc_array);
+
+  for (unsigned int i = 0; i < richloc->get_num_locations (); i++)
+    {
+      const location_range *loc_range = richloc->get_range (i);
+      json::object *loc_obj = json_from_location_range (loc_range, i);
+      if (loc_obj)
+	loc_array->append (loc_obj);
+    }
+
+  if (richloc->get_num_fixit_hints ())
+    {
+      json::array *fixit_array = new json::array ();
+      diag_obj->set ("fixits", fixit_array);
+      for (unsigned int i = 0; i < richloc->get_num_fixit_hints (); i++)
+	{
+	  const fixit_hint *hint = richloc->get_fixit_hint (i);
+	  json::object *fixit_obj = json_from_fixit_hint (hint);
+	  fixit_array->append (fixit_obj);
+	}
+    }
+
+  /* TODO: tree-ish things:
+     TODO: functions
+     TODO: inlining information
+     TODO: macro expansion information.  */
+}
+
+/* No-op implementation of "begin_group_cb" for JSON output.  */
+
+static void
+json_begin_group (diagnostic_context *)
+{
+}
+
+/* Implementation of "end_group_cb" for JSON output.  */
+
+static void
+json_end_group (diagnostic_context *)
+{
+  cur_group = NULL;
+  cur_children_array = NULL;
+}
+
+/* Callback for final cleanup for JSON output.  */
+
+static void
+json_final_cb (diagnostic_context *)
+{
+  /* Flush the top-level array.  */
+  toplevel_array->dump (stderr);
+  fprintf (stderr, "\n");
+  delete toplevel_array;
+  toplevel_array = NULL;
+}
+
+/* Set the output format for CONTEXT to FORMAT.  */
+
+void
+diagnostic_output_format_init (diagnostic_context *context,
+			       enum diagnostics_output_format format)
+{
+  switch (format)
+    {
+    default:
+      gcc_unreachable ();
+    case DIAGNOSTICS_OUTPUT_FORMAT_TEXT:
+      /* The default; do nothing.  */
+      break;
+
+    case DIAGNOSTICS_OUTPUT_FORMAT_JSON:
+      {
+	/* Set up top-level JSON array.  */
+	if (toplevel_array == NULL)
+	  toplevel_array = new json::array ();
+
+	/* Override callbacks.  */
+	context->begin_diagnostic = json_begin_diagnostic;
+	context->end_diagnostic = json_end_diagnostic;
+	context->begin_group_cb = json_begin_group;
+	context->end_group_cb =  json_end_group;
+	context->final_cb =  json_final_cb;
+
+	/* The option is handled in JSON format, rather than as text.  */
+	context->show_option_requested = false;
+
+	/* Don't colorize the text.  */
+	pp_show_color (context->printer) = false;
+      }
+      break;
+    }
+}