Bug 1553482 - Use BinASTInterfaceAndField in Context;r=arai

Depends on D32295

Differential Revision: https://phabricator.services.mozilla.com/D32395

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

Cargo.lock

@@ -229,6 +229,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "binast"
 version = "0.1.1"
 dependencies = [
+ "Inflector 0.11.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "binjs_meta 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.31.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",

js/src/frontend/BinAST.yaml

@@ -91,6 +91,7 @@ hpp:
       #define frontend_BinASTParser_h
 
       #include "mozilla/Maybe.h"
+      #include "mozilla/Variant.h"
 
       #include "frontend/BCEParserHandle.h"
       #include "frontend/BinASTParserPerTokenizer.h"
@@ -122,6 +123,9 @@ hpp:
         using AutoTaggedTuple = typename Tokenizer::AutoTaggedTuple;
         using Chars = typename Tokenizer::Chars;
         using Context = typename BinASTTokenReaderBase::Context;
+        using ListContext = typename BinASTTokenReaderBase::ListContext;
+        using FieldContext = typename BinASTTokenReaderBase::FieldContext;
+        using RootContext = typename BinASTTokenReaderBase::RootContext;
 
        public:
         // Auto-generated types.
@@ -637,7 +641,7 @@ BreakStatement:
       block:
         replace: |
           RootedAtom label(cx_);
-          MOZ_TRY_VAR(label, tokenizer_->readMaybeAtom(fieldContext++));
+          MOZ_TRY_VAR(label, tokenizer_->readMaybeAtom(Context(FieldContext(BinASTInterfaceAndField::BreakStatement__Label))));
 
   build: |
     if (label) {
@@ -781,7 +785,7 @@ ContinueStatement:
       block:
         replace: |
           RootedAtom label(cx_);
-          MOZ_TRY_VAR(label, tokenizer_->readMaybeAtom(fieldContext++));
+          MOZ_TRY_VAR(label, tokenizer_->readMaybeAtom(Context(FieldContext(BinASTInterfaceAndField::ContinueStatement__Label))));
 
   build: |
     if (label) {
@@ -1294,7 +1298,7 @@ LiteralRegExpExpression:
       block:
         replace: |
           Chars flags(cx_);
-          MOZ_TRY(tokenizer_->readChars(flags, fieldContext++));
+          MOZ_TRY(tokenizer_->readChars(flags, Context(FieldContext(BinASTInterfaceAndField::BreakStatement__Label))));
   build: |
     RegExpFlags reflags = RegExpFlag::NoFlags;
     for (auto c : flags) {

js/src/frontend/BinASTParser.h

@@ -13,6 +13,7 @@
 #define frontend_BinASTParser_h
 
 #include "mozilla/Maybe.h"
+#include "mozilla/Variant.h"
 
 #include "frontend/BCEParserHandle.h"
 #include "frontend/BinASTParserPerTokenizer.h"
@@ -44,6 +45,9 @@ class BinASTParser : public BinASTParserPerTokenizer<Tok> {
   using AutoTaggedTuple = typename Tokenizer::AutoTaggedTuple;
   using Chars = typename Tokenizer::Chars;
   using Context = typename BinASTTokenReaderBase::Context;
+  using ListContext = typename BinASTTokenReaderBase::ListContext;
+  using FieldContext = typename BinASTTokenReaderBase::FieldContext;
+  using RootContext = typename BinASTTokenReaderBase::RootContext;
 
  public:
   // Auto-generated types.

js/src/frontend/BinASTParserPerTokenizer.cpp

@@ -133,7 +133,7 @@ JS::Result<ParseNode*> BinASTParserPerTokenizer<Tok>::parseAux(
   MOZ_TRY(tokenizer_->readHeader());
 
   ParseNode* result(nullptr);
-  const Context topContext(Context::topLevel());
+  const Context topContext((RootContext()));
   MOZ_TRY_VAR(result, asFinalParser()->parseProgram(topContext));
 
   mozilla::Maybe<GlobalScope::Data*> bindings =
@@ -196,7 +196,7 @@ JS::Result<FunctionNode*> BinASTParserPerTokenizer<Tok>::parseLazyFunction(
 
   // Inject a toplevel context (i.e. no parent) to parse the lazy content.
   // In the future, we may move this to a more specific context.
-  const Context context(Context::topLevel());
+  const Context context((RootContext()));
   MOZ_TRY(
       (asFinalParser()->*parseFunc)(func->nargs(), &params, &tmpBody, context));
 

js/src/frontend/BinASTParserPerTokenizer.h

@@ -57,6 +57,7 @@ class BinASTParserPerTokenizer : public BinASTParserBase,
   using AutoTaggedTuple = typename Tokenizer::AutoTaggedTuple;
   using BinASTFields = typename Tokenizer::BinASTFields;
   using Chars = typename Tokenizer::Chars;
+  using RootContext = BinASTTokenReaderBase::RootContext;
   using Context = BinASTTokenReaderBase::Context;
 
  public:

js/src/frontend/BinASTTokenReaderBase.h

@@ -7,6 +7,8 @@
 #ifndef frontend_BinASTTokenReaderBase_h
 #define frontend_BinASTTokenReaderBase_h
 
+#include "mozilla/Variant.h"
+
 #include <string.h>
 
 #include "frontend/BinASTToken.h"
@@ -27,54 +29,31 @@ class MOZ_STACK_CLASS BinASTTokenReaderBase {
   template <typename T>
   using ErrorResult = mozilla::GenericErrorResult<T>;
 
-  // The context in which we read a token.
-  struct Context {
-    // Construct a context for a root node.
-    constexpr static Context topLevel() {
-      return Context(BinASTKind::_Null, 0, ElementOf::TaggedTuple);
-    }
+  // Part of variant `Context`
+  // Reading the root of the tree, before we enter any tagged tuple.
+  struct RootContext {};
 
-    Context arrayElement() const {
-      return Context(kind, fieldIndex, ElementOf::Array);
-    }
-
-    // Construct a context for a field of a tagged tuple.
-    constexpr static Context firstField(BinASTKind kind) {
-      return Context(kind, 0, ElementOf::TaggedTuple);
-    }
-
-    const Context operator++(int) {
-      MOZ_ASSERT(elementOf == ElementOf::TaggedTuple);
-      Context result = *this;
-      fieldIndex++;
-      return result;
-    }
-
-    // The kind of the tagged tuple containing the token.
-    //
-    // If the parent is the root, use `BinASTKind::_Null`.
-    BinASTKind kind;
-
-    // The index of the token as a field of the parent.
-    uint8_t fieldIndex;
-
-    enum class ElementOf {
-      // This token is an element of an array.
-      Array,
-
-      // This token is a field of a tagged tuple.
-      TaggedTuple,
-    };
-    ElementOf elementOf;
-
-    Context() = delete;
-
-   private:
-    constexpr Context(BinASTKind kind_, uint8_t fieldIndex_,
-                      ElementOf elementOf_)
-        : kind(kind_), fieldIndex(fieldIndex_), elementOf(elementOf_) {}
+  // Part of variant `Context`
+  // Reading an element from a list.
+  struct ListContext {
+    const BinASTInterfaceAndField position;
+    const BinASTList content;
+    ListContext(const BinASTInterfaceAndField position,
+                const BinASTList content)
+        : position(position), content(content) {}
   };
 
+  // Part of variant `Context`
+  // Reading a field from an interface.
+  struct FieldContext {
+    const BinASTInterfaceAndField position;
+    explicit FieldContext(const BinASTInterfaceAndField position)
+        : position(position) {}
+  };
+
+  // The context in which we read a token.
+  typedef mozilla::Variant<RootContext, ListContext, FieldContext> Context;
+
   // The information needed to skip a subtree.
   class SkippableSubTree {
    public:

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

@@ -1097,7 +1097,7 @@ enum class BinASTInterfaceAndField: uint16_t {
                                         }
                                         // Keep the simple name of sums and lists if there is one.
                                         match *alias_type.spec() {
-                                            TypeSpec::TypeSum(ref contents ) => {
+                                            TypeSpec::TypeSum(_) => {
                                                 if optional {
                                                     Cow::from(format!("OPTIONAL_SUM({name})", name = name.to_cpp_enum_case()))
                                                 } else {
@@ -1632,8 +1632,8 @@ impl CPPExporter {
     MOZ_TRY(tokenizer_->enterList(length, context, guard));{empty_check}
 {init}
 
-    const Context childContext(context.arrayElement());
     for (uint32_t i = 0; i < length; ++i) {{
+        const Context childContext(Context(ListContext(context.as<FieldContext>().position, BinASTList::{content_kind})));
 {call}
 {append}    }}
 
@@ -1641,6 +1641,7 @@ impl CPPExporter {
     return result;
 }}\n",
             first_line = first_line,
+            content_kind = parser.name.to_class_cases(),
             empty_check =
                 if parser.supports_empty {
                     "".to_string()
@@ -1963,7 +1964,9 @@ impl CPPExporter {
 
         let mut fields_implem = String::new();
         for field in interface.contents().fields() {
-            let context = "fieldContext++";
+            let context = format!("Context(FieldContext(BinASTInterfaceAndField::{kind}__{field}))",
+                kind = name.to_cpp_enum_case(),
+                field = field.name().to_cpp_enum_case());
 
             let rules_for_this_field = rules_for_this_interface.by_field.get(field.name())
                 .cloned()
@@ -2165,7 +2168,7 @@ impl CPPExporter {
 {{
     MOZ_ASSERT(kind == BinASTKind::{kind});
     BINJS_TRY(CheckRecursionLimit(cx_));
-{maybe_field_context}{check_fields}
+{check_fields}
 {pre}{fields_implem}
 {post}    return result;
 }}
@@ -2177,11 +2180,6 @@ impl CPPExporter {
                 post = build_result.newline_if_not_empty(),
                 kind = name.to_cpp_enum_case(),
                 first_line = first_line,
-                maybe_field_context = if interface.contents().fields().len() > 0 {
-                    "    Context fieldContext = Context::firstField(kind);\n"
-                } else {
-                    ""
-                },
             ));
         }
     }