Bug 1553482 - Generating BINAST_TOTAL_NUMBER_OF_FIELDS, BINAST_NUMBER_OF_LIST_TYPES;r=arai

Differential Revision: https://phabricator.services.mozilla.com/D32289

--HG--
extra : moz-landing-system : lando

js/src/frontend/BinASTToken.h

@@ -289,6 +289,10 @@ enum class BinASTField : uint16_t {
 // The number of distinct values of BinASTField.
 const size_t BINASTFIELD_LIMIT = 69;
 
+// The total number of fields across all interfaces. Used typically to maintain
+// a probability table per field.
+const size_t BINAST_TOTAL_NUMBER_OF_FIELDS = 275;
+
 /**
  * The different variants of Binary AST string enums, as per
  * the specifications of Binary AST, as a single macro and
@@ -365,6 +369,10 @@ enum class BinASTVariant : uint16_t {
 // The number of distinct values of BinASTVariant.
 const size_t BINASTVARIANT_LIMIT = 49;
 
+// The total number of lists across all interfaces. Used typically to maintain a
+// probability table per field.
+const size_t BINAST_TOTAL_NUMBER_OF_LISTS = 22;
+
 /**
  * Return a string describing a `BinASTKind`.
  */

js/src/frontend/binast/src/main.rs

@@ -994,7 +994,13 @@ enum class BinASTField: uint16_t {
 #undef EMIT_ENUM
 };
 ");
-        buffer.push_str(&format!("\n// The number of distinct values of BinASTField.\nconst size_t BINASTFIELD_LIMIT = {};\n\n\n", field_limit));
+        buffer.push_str(&format!("\n// The number of distinct values of BinASTField.\nconst size_t BINASTFIELD_LIMIT = {};\n", field_limit));
+
+        let total_number_of_fields: usize = self.syntax.interfaces_by_name()
+            .values()
+            .map(|interface| interface.contents().fields().len())
+            .sum();
+        buffer.push_str(&format!("\n// The total number of fields across all interfaces. Used typically to maintain a probability table per field.\nconst size_t BINAST_TOTAL_NUMBER_OF_FIELDS = {};\n\n\n", total_number_of_fields));
 
         if self.rules.hpp_tokens_variants_doc.is_some() {
             buffer.push_str(&self.rules.hpp_tokens_variants_doc.reindent(""));
@@ -1024,6 +1030,8 @@ enum class BinASTVariant: uint16_t {
         buffer.push_str(&format!("\n// The number of distinct values of BinASTVariant.\nconst size_t BINASTVARIANT_LIMIT = {};\n\n\n",
             variants_limit));
 
+        buffer.push_str(&format!("\n// The total number of lists across all interfaces. Used typically to maintain a probability table per field.\nconst size_t BINAST_TOTAL_NUMBER_OF_LISTS = {};\n\n\n", self.list_parsers_to_generate.len()));
+
         buffer.push_str(&self.rules.hpp_tokens_footer.reindent(""));
         buffer.push_str("\n");
     }