This patch adds support for emitting diagnostics about JSON input files
to global_dc, showing both the file/line/columns and the JSON Pointer
for the problematic json::value. Test coverage is added by the followup
on aarch64.
gcc/ChangeLog:
* Makefile.in (OBJS-libcommon): Add json-diagnostic.o.
* diagnostics/client-data-hooks.h
(class client_data_hooks_decorator): New.
* diagnostics/context.cc (context::set_client_data_hooks): Return
the old hooks.
* diagnostics/context.h (context::set_client_data_hooks): Update
decl likewise.
* json-diagnostic.cc: New file.
* json-diagnostic.h: New file.
Signed-off-by: David Malcolm <[email protected]>
---
gcc/Makefile.in | 2 +-
gcc/diagnostics/client-data-hooks.h | 53 ++++
gcc/diagnostics/context.cc | 5 +-
gcc/diagnostics/context.h | 4 +-
gcc/json-diagnostic.cc | 374 ++++++++++++++++++++++++++++
gcc/json-diagnostic.h | 74 ++++++
6 files changed, 508 insertions(+), 4 deletions(-)
create mode 100644 gcc/json-diagnostic.cc
create mode 100644 gcc/json-diagnostic.h
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 54865765b6ef6..d4170dd7a3262 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1905,7 +1905,7 @@ OBJS-libcommon = \
gcc-diagnostic-spec.o \
graphviz.o pex.o \
pretty-print.o intl.o \
- json.o json-parsing.o \
+ json.o json-parsing.o json-diagnostic.o \
pub-sub.o \
xml.o \
sbitmap.o \
diff --git a/gcc/diagnostics/client-data-hooks.h
b/gcc/diagnostics/client-data-hooks.h
index 6fa31d0d65e00..bd760dcb70bba 100644
--- a/gcc/diagnostics/client-data-hooks.h
+++ b/gcc/diagnostics/client-data-hooks.h
@@ -63,6 +63,59 @@ class client_data_hooks
add_sarif_invocation_properties (sarif_object &invocation_obj) const = 0;
};
+/* Implementation of client_data_hooks that delegates vfuncs to an
+ optional inner object. */
+
+class client_data_hooks_decorator : public client_data_hooks
+{
+ public:
+ client_data_hooks_decorator (const client_data_hooks *inner)
+ : m_inner (inner)
+ {
+ }
+
+ const client_version_info *get_any_version_info () const override
+ {
+ if (m_inner)
+ return m_inner->get_any_version_info ();
+ return nullptr;
+ }
+
+ const logical_locations::manager *
+ get_logical_location_manager () const override
+ {
+ if (m_inner)
+ return m_inner->get_logical_location_manager ();
+ return nullptr;
+ }
+
+ logical_locations::key
+ get_current_logical_location () const override
+ {
+ if (m_inner)
+ return m_inner->get_current_logical_location ();
+ return logical_locations::key ();
+ }
+
+ const char *
+ maybe_get_sarif_source_language (const char *filename) const override
+ {
+ if (m_inner)
+ return m_inner->maybe_get_sarif_source_language (filename);
+ return nullptr;
+ }
+
+ void
+ add_sarif_invocation_properties (sarif_object &invocation_obj) const override
+ {
+ if (m_inner)
+ m_inner->add_sarif_invocation_properties (invocation_obj);
+ }
+
+private:
+ const client_data_hooks *m_inner;
+};
+
class client_plugin_info;
/* Abstract base class for a diagnostics::context to get at
diff --git a/gcc/diagnostics/context.cc b/gcc/diagnostics/context.cc
index 03d570665843d..98af6ecb1b665 100644
--- a/gcc/diagnostics/context.cc
+++ b/gcc/diagnostics/context.cc
@@ -529,12 +529,13 @@ context::set_main_input_filename (const char *filename)
sink_->set_main_input_filename (filename);
}
-void
+std::unique_ptr<client_data_hooks>
context::set_client_data_hooks (std::unique_ptr<client_data_hooks> hooks)
{
- delete m_client_data_hooks;
+ std::unique_ptr<client_data_hooks> old_hooks (m_client_data_hooks);
/* Ideally the field would be a std::unique_ptr here. */
m_client_data_hooks = hooks.release ();
+ return old_hooks;
}
void
diff --git a/gcc/diagnostics/context.h b/gcc/diagnostics/context.h
index 742319fbd204f..514ff1e68f9b8 100644
--- a/gcc/diagnostics/context.h
+++ b/gcc/diagnostics/context.h
@@ -388,7 +388,9 @@ public:
/* Various setters for use by option-handling logic. */
void set_sink (std::unique_ptr<sink> sink_);
void set_text_art_charset (enum diagnostic_text_art_charset charset);
- void set_client_data_hooks (std::unique_ptr<client_data_hooks> hooks);
+
+ std::unique_ptr<client_data_hooks>
+ set_client_data_hooks (std::unique_ptr<client_data_hooks> hooks);
void push_owned_urlifier (std::unique_ptr<urlifier>);
void push_borrowed_urlifier (const urlifier &);
diff --git a/gcc/json-diagnostic.cc b/gcc/json-diagnostic.cc
new file mode 100644
index 0000000000000..bf61cd0007ecf
--- /dev/null
+++ b/gcc/json-diagnostic.cc
@@ -0,0 +1,374 @@
+/* Diagnostics relating to JSON values.
+ Copyright (C) 2026 Free Software Foundation, Inc.
+ Contributed by David Malcolm <[email protected]>.
+
+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/>. */
+
+#define INCLUDE_MAP
+#define INCLUDE_STRING
+#define INCLUDE_VECTOR
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "intl.h"
+#include "diagnostic.h"
+#include "json-diagnostic.h"
+#include "diagnostics/dumping.h"
+#include "diagnostics/logging.h"
+#include "diagnostics/logical-locations.h"
+#include "diagnostics/client-data-hooks.h"
+#include "diagnostics/text-sink.h"
+#include "diagnostics/physical-location-maker.h"
+#include "pretty-print-markup.h"
+
+static bool
+emit_json_diagnostic (gcc_json_context &ctxt,
+ enum diagnostics::kind kind,
+ const json::value &js_val,
+ diagnostics::option_id option_id,
+ const char *gmsgid, va_list *ap)
+ ATTRIBUTE_GCC_DIAG(5,0);
+
+using log_function_params = diagnostics::logging::log_function_params;
+using auto_inc_log_depth = diagnostics::logging::auto_inc_depth;
+
+class json_logical_location_manager
+ : public diagnostics::logical_locations::manager
+{
+public:
+ using key = diagnostics::logical_locations::key;
+ using kind = diagnostics::logical_locations::kind;
+
+ void
+ dump (FILE *outfile, int indent) const final override
+ {
+ diagnostics::dumping::emit_heading (outfile, indent,
+ "json_logical_location_manager");
+ }
+
+ label_text
+ get_short_name (key k) const final override
+ {
+ auto *js_val = js_from_key (k);
+ const json::pointer::token &pointer_token = js_val->get_pointer_token ();
+ pretty_printer pp;
+ pointer_token.print (&pp);
+ return label_text::take (xstrdup (pp_formatted_text (&pp)));
+ }
+
+ label_text
+ get_name_with_scope (key k) const final override
+ {
+ auto *js_val = js_from_key (k);
+ pretty_printer pp;
+ js_val->print_pointer (&pp);
+ return label_text::take (xstrdup (pp_formatted_text (&pp)));
+ }
+
+ label_text
+ get_internal_name (key) const final override
+ {
+ return label_text ();
+ }
+
+ kind
+ get_kind (key k) const final override
+ {
+ auto *js_val = js_from_key (k);
+
+ switch (js_val->get_kind ())
+ {
+ default:
+ gcc_unreachable ();
+
+ case json::JSON_OBJECT:
+ return kind::object;
+
+ case json::JSON_ARRAY:
+ return kind::array;
+
+ case json::JSON_INTEGER:
+ case json::JSON_FLOAT:
+ case json::JSON_STRING:
+ case json::JSON_TRUE:
+ case json::JSON_FALSE:
+ case json::JSON_NULL:
+ return kind::property;
+ }
+ }
+
+ label_text
+ get_name_for_path_output (key k) const final override
+ {
+ return get_name_with_scope (k);
+ }
+
+ key
+ get_parent (key k) const final override
+ {
+ auto *js_val = js_from_key (k);
+ auto &pointer_token = js_val->get_pointer_token ();
+ return key_from_js (pointer_token.m_parent);
+ }
+
+ static const json::value *
+ js_from_key (key k)
+ {
+ return k.cast_to<const json::value *> ();
+ }
+
+ static key
+ key_from_js (const json::value *js_val)
+ {
+ return key::from_ptr (js_val);
+ }
+
+private:
+ static void
+ print_json_pointer_token (pretty_printer *);
+};
+
+/* Implementation of diagnostics::client_data_hooks
+ for reporting a diagnostic at a particular json::value
+ in a JSON input file.
+
+ It wraps another hooks instance, but uses a
+ json_logical_location_manager, has a specific
+ json::value for the current logical location,
+ and treats the SARIF source lang as "json". */
+
+class json_client_data_hooks : public diagnostics::client_data_hooks_decorator
+{
+public:
+ json_client_data_hooks (const json::value &js_val,
+ const client_data_hooks *inner)
+ : diagnostics::client_data_hooks_decorator (inner),
+ m_js_val (js_val)
+ {}
+
+ const diagnostics::logical_locations::manager *
+ get_logical_location_manager () const override
+ {
+ return &m_logical_loc_mgr;
+ }
+
+ diagnostics::logical_locations::key
+ get_current_logical_location () const override
+ {
+ /* Use the json value's pointer as the key. */
+ return json_logical_location_manager::key_from_js (&m_js_val);
+ }
+
+ const char *
+ maybe_get_sarif_source_language (const char *) const override
+ {
+ return "json";
+ }
+
+private:
+ json_logical_location_manager m_logical_loc_mgr;
+ const json::value &m_js_val;
+};
+
+namespace pp_markup {
+
+/* Print the JSON Pointer of a given json::value in quotes. */
+
+class quoted_json_pointer : public pp_element
+{
+public:
+ quoted_json_pointer (const json::value &js_val)
+ : m_js_val (js_val)
+ {
+ }
+
+ void
+ add_to_phase_2 (context &ctxt) final override
+ {
+ ctxt.begin_quote ();
+ m_js_val.print_pointer (&ctxt.m_pp);
+ ctxt.end_quote ();
+ }
+
+private:
+ const json::value &m_js_val;
+};
+
+} // namespace pp_markup
+
+/* text_sink starter for diagnostics relating to JSON. */
+
+static void
+json_text_starter (diagnostics::text_sink &sink,
+ const diagnostics::diagnostic_info *diagnostic)
+{
+ pretty_printer *pp = sink.get_printer ();
+
+ /* If this isn't the root value, report its json pointer. */
+ diagnostics::logical_locations::key k;
+ if (auto data_hooks = sink.get_context ().get_client_data_hooks ())
+ k = data_hooks->get_current_logical_location ();
+ const json::value *js_val = json_logical_location_manager::js_from_key (k);
+ if (js_val && js_val->get_pointer_token ().m_parent)
+ {
+ const char *file = LOCATION_FILE (diagnostic_location (diagnostic));
+ char *new_prefix = file ? sink.file_name_as_prefix (file) : nullptr;
+ pp_set_prefix (pp, new_prefix);
+
+ pp_markup::quoted_json_pointer e (*js_val);
+ switch (js_val->get_kind ())
+ {
+ default:
+ pp_printf (pp, _("In JSON value %e"), &e);
+ break;
+ case json::JSON_OBJECT:
+ pp_printf (pp, _("In JSON object %e"), &e);
+ break;
+ case json::JSON_ARRAY:
+ pp_printf (pp, _("In JSON array %e"), &e);
+ break;
+ }
+ pp_newline (pp);
+ }
+
+ pp_set_prefix (pp, sink.build_prefix (*diagnostic));
+}
+
+
+/* class gcc_json_context : public json::simple_location_map. */
+
+location_t
+gcc_json_context::make_location_for_point (const json::location_map::point &p)
+{
+ diagnostics::physical_location_maker m (line_table);
+ return m.new_location_from_file_line_column (m_filename,
+ p.m_line,
+ p.m_column + 1);
+}
+
+location_t
+gcc_json_context::make_location_for_range (const json::location_map::range &r)
+{
+ location_t start_loc = make_location_for_point (r.m_start);
+ location_t end_loc = make_location_for_point (r.m_end);
+ return make_location (start_loc, start_loc, end_loc);
+}
+
+/* Emit a diagnostic on global_dc of the relevant KIND relating to JS_VAL,
+ using CTXT to get at file/line/column info.
+
+ Temporarily override global_dc's logical location to refer to JS_VAL
+ and the text_sink starter and finalizer to be suitable for handling
+ reporting within a JSON file. */
+
+static bool
+emit_json_diagnostic (gcc_json_context &ctxt,
+ enum diagnostics::kind kind,
+ const json::value &js_val,
+ diagnostics::option_id option_id,
+ const char *gmsgid, va_list *ap)
+{
+ auto logger = global_dc->get_logger ();
+ log_function_params (logger, __func__)
+ .log_param_option_id ("option_id", option_id)
+ .log_param_string ("gmsgid", gmsgid);
+ auto_inc_log_depth depth_sentinel (logger);
+
+ auto_diagnostic_group d;
+
+ // Get physical location for JS_VAL.
+ location_t phys_loc
+ = ctxt.make_location_for_range (ctxt.get_range_for_value (js_val));
+ rich_location richloc (line_table, phys_loc);
+
+ // Set logical location by overriding client data hooks
+ auto tmp_client_data_hooks
+ = std::make_unique<json_client_data_hooks>
+ (js_val, global_dc->get_client_data_hooks ());
+ auto old_client_data_hooks
+ = global_dc->set_client_data_hooks (std::move (tmp_client_data_hooks));
+
+ // Override text hooks
+ auto old_text_starter = text_starter (global_dc);
+ auto old_text_finalizer = text_finalizer (global_dc);
+ text_starter (global_dc) = json_text_starter;
+ text_finalizer (global_dc) = diagnostics::default_text_finalizer;
+
+ bool ret = global_dc->diagnostic_impl (&richloc, nullptr, option_id,
+ gmsgid, ap, kind);
+
+ // Restore old text and client data hooks:
+ text_starter (global_dc) = old_text_starter;
+ text_finalizer (global_dc) = old_text_finalizer;
+ global_dc->set_client_data_hooks (std::move (old_client_data_hooks));
+
+ if (logger)
+ logger->log_bool_return ("emit_diagnostic", ret);
+
+ return ret;
+}
+
+
+/* Emit an error on gcc's global_dc relating to JS_VAL. */
+
+void
+json_error (gcc_json_context &ctxt,
+ const json::value &js_val,
+ const char *gmsgid, ...)
+{
+ va_list ap;
+ va_start (ap, gmsgid);
+ emit_json_diagnostic (ctxt,
+ diagnostics::kind::error,
+ js_val, -1,
+ gmsgid, &ap);
+ va_end (ap);
+}
+
+/* Emit a warning on gcc's global_dc relating to JS_VAL. */
+
+bool
+json_warning (gcc_json_context &ctxt,
+ const json::value &js_val,
+ diagnostics::option_id option_id,
+ const char *gmsgid, ...)
+{
+ va_list ap;
+ va_start (ap, gmsgid);
+ bool ret = emit_json_diagnostic (ctxt,
+ diagnostics::kind::warning,
+ js_val, option_id,
+ gmsgid, &ap);
+ va_end (ap);
+ return ret;
+}
+
+/* Emit a note on gcc's global_dc relating to JS_VAL. */
+
+void
+json_note (gcc_json_context &ctxt,
+ const json::value &js_val,
+ const char *gmsgid, ...)
+{
+ va_list ap;
+ va_start (ap, gmsgid);
+ emit_json_diagnostic (ctxt,
+ diagnostics::kind::note,
+ js_val, -1,
+ gmsgid, &ap);
+ va_end (ap);
+}
diff --git a/gcc/json-diagnostic.h b/gcc/json-diagnostic.h
new file mode 100644
index 0000000000000..1773ee0a0fd50
--- /dev/null
+++ b/gcc/json-diagnostic.h
@@ -0,0 +1,74 @@
+/* Diagnostics relating to JSON values.
+ Copyright (C) 2026 Free Software Foundation, Inc.
+ Contributed by David Malcolm <[email protected]>.
+
+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_JSON_DIAGNOSTIC_H
+#define GCC_JSON_DIAGNOSTIC_H
+
+#include "json-parsing.h"
+
+/* Implementation of json::location_map for use with
+ GCC diagnostics.
+ Stores location information for json::value * from parsing, and
+ can generate location_t values for the. */
+
+class gcc_json_context : public json::simple_location_map
+{
+public:
+ gcc_json_context (const char *filename)
+ : m_filename (filename)
+ {
+ }
+
+ location_t
+ make_location_for_point (const json::location_map::point &);
+
+ location_t
+ make_location_for_range (const json::location_map::range &);
+
+private:
+ const char *m_filename;
+};
+
+/* Emit an error on gcc's global_dc relating to JS_VAL. */
+
+extern void
+json_error (gcc_json_context &ctxt,
+ const json::value &js_val,
+ const char *gmsgid, ...)
+ ATTRIBUTE_GCC_DIAG(3,4);
+
+/* Emit a warning on gcc's global_dc relating to JS_VAL. */
+
+extern bool
+json_warning (gcc_json_context &ctxt,
+ const json::value &js_val,
+ diagnostics::option_id option_id,
+ const char *gmsgid, ...)
+ ATTRIBUTE_GCC_DIAG(4,5);
+
+/* Emit a note on gcc's global_dc relating to JS_VAL. */
+
+extern void
+json_note (gcc_json_context &ctxt,
+ const json::value &js_val,
+ const char *gmsgid, ...)
+ ATTRIBUTE_GCC_DIAG(3,4);
+
+#endif /* GCC_JSON_DIAGNOSTIC_H */
--
2.26.3
