Determines which fields can be deleted

1 files changed, 72 insertions, 3 deletions

diff --git a/gcc/ipa-hello-world.c b/gcc/ipa-hello-world.c
index 6d911082b58..30b260e7934 100644
--- a/gcc/ipa-hello-world.c
+++ b/gcc/ipa-hello-world.c
@@ -61,7 +61,6 @@ struct field_comparator
     const enum tree_code tree_code_right_record = TREE_CODE(right_record);
     const bool is_left_record_type = RECORD_TYPE == tree_code_left_record;
     const bool is_right_record_type = RECORD_TYPE == tree_code_right_record;
-    log("left type is weird %s\n", get_type_name(left_record));
     gcc_assert(is_left_record_type);
     gcc_assert(is_right_record_type);
     const bool are_left_and_right_valid = is_left_record_type && is_right_record_type;
@@ -105,6 +104,8 @@ struct field_comparator
 
 typedef std::map<fields, accesses, field_comparator> field_access_counter;
 typedef std::set<const_tree> record_set;
+typedef std::set<fields> record_field_set;
+
 enum access_code { READ_ACCESS, WRITE_ACCESS };
 
 void
@@ -284,6 +285,26 @@ count_access_for_types_in_function(cgraph_node *cnode, const record_set &non_esc
   pop_cfun();
 }
 
+void
+init_field_access_counter(field_access_counter &counter, const record_set &non_escaping_records)
+{
+  for (auto it = non_escaping_records.cbegin(); it != non_escaping_records.cend(); ++it)
+  {
+    const_tree record = *it;
+    gcc_assert(record);
+    enum tree_code tree_code_record_type = TREE_CODE(record);
+    const bool is_record_type = RECORD_TYPE == tree_code_record_type;
+    gcc_assert(is_record_type);
+
+    for (tree field = TYPE_FIELDS (record); field; field = DECL_CHAIN (field))
+    {
+      gcc_assert(field);
+      const std::pair<const_tree, const_tree> struct_field_pair = std::make_pair(record, field);
+      counter[struct_field_pair] = { 0, 0 };
+    }
+  }
+}
+
 /* INFO:
  * Yes, I know we are returning a std::map.
  * Bad pattern? Maybe, but this will only be called once
@@ -299,6 +320,7 @@ field_access_counter
 count_access_for_types_in_linking_unit(const record_set &non_escaping_records)
 {
   field_access_counter counter;
+  init_field_access_counter(counter, non_escaping_records);
   cgraph_node *cnode = NULL;
   FOR_EACH_DEFINED_FUNCTION(cnode)
   {
@@ -338,13 +360,60 @@ calculate_non_escaping_records(type_map &escaping_type_info)
   return non_escaping_records;
 }
 
-static unsigned int
-iphw_execute()
+static field_access_counter
+count_field_accesses()
 {
+  
   type_map escaping_types;
   calculate_escaping_types(escaping_types);
   const record_set non_escaping_records = calculate_non_escaping_records(escaping_types); 
   field_access_counter counter = count_access_for_types_in_linking_unit(non_escaping_records);
+  return counter;
+}
+
+static record_field_set
+get_fields_to_reorg()
+{
+  const field_access_counter counter = count_field_accesses();
+  record_field_set records_and_fields_to_reorg;
+  for (auto it = counter.cbegin(); it != counter.cend(); ++it)
+  {
+     fields record_field_pair = it->first;
+     accesses counter = it->second;
+     const_tree record = record_field_pair.first;
+     const_tree field = record_field_pair.second;
+     // We are interested in reads == 0;
+     unsigned reads = counter.first;
+     log("final count for %s.%s = %d\n", get_type_name(record), get_field_name(field), reads);
+     if (0 != reads) continue;
+
+     records_and_fields_to_reorg.insert(record_field_pair);
+  }
+
+  return records_and_fields_to_reorg;
+}
+
+static void
+print_record_field_set(const record_field_set &to_reorg)
+{
+  log("I am about to print\n");
+  for (auto it = to_reorg.cbegin(); it != to_reorg.cend(); ++it)
+  {
+    fields record_field_pair = *it;
+    const_tree record = record_field_pair.first;
+    const_tree field = record_field_pair.second;
+    // TODO: Some fields / records might be anonymous
+    log("will eliminate %s.%s\n", get_type_name(record), get_field_name(field));
+  }
+}
+
+
+static unsigned int
+iphw_execute()
+{
+  const record_field_set to_reorg = get_fields_to_reorg();
+  log("I am about to enter print function\n");
+  print_record_field_set(to_reorg);
   return 0;
 }