From 750aa8e568e1a00217f9a82a96e98c28e2c52834 Mon Sep 17 00:00:00 2001
From: David Malcolm <dmalcolm@redhat.com>
Date: Thu, 2 Oct 2025 11:49:32 -0400
Subject: [PATCH 26/30] FIXME: C AST

---
 gcc/c/c-parser.cc | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 9816a9425ce..9acbfd396b5 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3.  If not see
    location rather than implicitly using input_location.  */
 
 #include "config.h"
+#define INCLUDE_LIST
 #define INCLUDE_STRING
 #include "system.h"
 #include "coretypes.h"
@@ -77,6 +78,9 @@ along with GCC; see the file COPYING3.  If not see
 #include "asan.h"
 #include "c-family/c-ubsan.h"
 #include "gcc-urlifier.h"
+#include "channels.h"
+#include "topics/ast-events.h"
+
 
 /* We need to walk over decls with incomplete struct/union/enum types
    after parsing the whole translation unit.
@@ -275,6 +279,10 @@ struct GTY(()) c_parser {
      Managed by c_parser_omp_metadirective.  */
   struct omp_metadirective_parse_data * GTY((skip))
     omp_metadirective_state;
+
+  // FIXME
+  const pub_sub::channel<gcc::topics::ast_events::subscriber> * GTY((skip))
+    ast_events_channel;
 };
 
 /* Holds data needed to restore the token stream to its previous state
@@ -299,6 +307,52 @@ vec<omp_begin_declare_variant_map_entry, va_gc> *omp_begin_declare_variant_map;
 static tree omp_start_variant_function (c_declarator *, tree);
 static void omp_finish_variant_function (tree, tree, tree);
 
+class auto_notify_ast_node
+{
+public:
+  auto_notify_ast_node (c_parser *parser, const char *kind)
+  : m_parser (parser),
+    m_kind (kind)
+  {
+    // FIXME: unlikely
+    // gengtype doesn't understand  [[unlikely]] , and is it legal
+    // in c++14 anyway?
+    if (parser->ast_events_channel)
+      parser->ast_events_channel->publish
+	(gcc::topics::ast_events::begin_node {kind, get_next_loc ()});
+  }
+
+  ~auto_notify_ast_node ()
+  {
+    // FIXME: unlikely
+#if 0
+    if (parser->ast_events_channel)
+      parser->ast_events_channel->publish
+	(gcc::topics::ast_events::end_node {m_kind, get_prev_loc ()});
+#endif
+  }
+
+  location_t
+  get_next_loc () const
+  {
+    return c_parser_peek_token (m_parser)->location;
+  }
+
+#if 0
+  location_t
+  get_prev_loc () const
+  {
+    if (const cp_token *tok = cp_lexer_safe_previous_token (m_parser->lexer))
+      return tok->location;
+    return UNKNOWN_LOCATION;
+  }
+#endif
+
+private:
+  c_parser *const m_parser;
+  const char *const m_kind;
+};
+
 /* Return a pointer to the Nth token in PARSERs tokens_buf.  */
 
 c_token *
@@ -2074,6 +2128,8 @@ private:
 static void
 c_parser_translation_unit (c_parser *parser)
 {
+  auto_notify_ast_node (parser, "translation-unit");
+
   if (c_parser_next_token_is (parser, CPP_EOF))
     {
       pedwarn (c_parser_peek_token (parser)->location, OPT_Wpedantic,
@@ -2168,6 +2224,8 @@ c_parser_translation_unit (c_parser *parser)
 static void
 c_parser_external_declaration (c_parser *parser)
 {
+  auto_notify_ast_node (parser, "external-declaration");
+
   int ext;
   switch (c_parser_peek_token (parser)->type)
     {
@@ -4111,6 +4169,8 @@ report_bad_enum_name (c_parser *parser)
 static struct c_typespec
 c_parser_enum_specifier (c_parser *parser)
 {
+  auto_notify_ast_node (parser, "enum-specifier");
+
   struct c_typespec ret;
   bool have_std_attrs;
   bool potential_nesting_p = false;
@@ -4382,6 +4442,7 @@ c_parser_enum_specifier (c_parser *parser)
 static struct c_typespec
 c_parser_struct_or_union_specifier (c_parser *parser)
 {
+  auto_notify_ast_node (parser, "struct-or-union-specifier");
   struct c_typespec ret;
   bool have_std_attrs;
   tree std_attrs = NULL_TREE;
@@ -4981,6 +5042,8 @@ struct c_declarator *
 c_parser_declarator (c_parser *parser, bool type_seen_p, c_dtr_syn kind,
 		     bool *seen_id)
 {
+  auto_notify_ast_node (parser, "declarator");
+
   /* Parse any initial pointer part.  */
   if (c_parser_next_token_is (parser, CPP_MULT))
     {
@@ -31291,6 +31354,9 @@ c_parse_file (void)
   if (tparser.tokens == &tparser.tokens_buf[0])
     the_parser->tokens = &the_parser->tokens_buf[0];
 
+  the_parser->ast_events_channel
+    = g->get_channels ().ast_events_channel.get_if_active ();
+
   /* Initialize EH, if we've been told to do so.  */
   if (flag_exceptions)
     using_eh_for_cleanups ();
-- 
2.49.0