[torque] Change syntax for "external constants"

This CL changes the syntax for external constants to better reflect
for what they are actually used.

Drive-by change: Ran the format tool on base.tq.

R=danno@chromium.org, tebbi@chromium.org

Bug: v8:7793
Change-Id: Ie49c28b9c95a05846a2d9801f01b11e5a58d72d9
Reviewed-on: https://chromium-review.googlesource.com/1111706Reviewed-by: Daniel Clifford <danno@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#53963}

src/torque/Torque.g4

@@ -277,7 +277,7 @@ externalRuntime : EXTERN RUNTIME IDENTIFIER typeListMaybeVarArgs optionalType ';
 builtinDeclaration : JAVASCRIPT? BUILTIN IDENTIFIER optionalGenericTypeList parameterList optionalType (helperBody | ';');
 genericSpecialization: IDENTIFIER genericSpecializationTypeList parameterList optionalType optionalLabelList helperBody;
 macroDeclaration : ('operator' STRING_LITERAL)? MACRO IDENTIFIER optionalGenericTypeList parameterList optionalType optionalLabelList (helperBody | ';');
-constDeclaration : 'const' IDENTIFIER ':' type '=' STRING_LITERAL ';';
+externConstDeclaration : 'const' IDENTIFIER ':' type generatesDeclaration ';';
 
 declaration
         : typeDeclaration
@@ -288,7 +288,7 @@ declaration
         | externalMacro
         | externalBuiltin
         | externalRuntime
-        | constDeclaration;
+        | externConstDeclaration;
 
 moduleDeclaration : MODULE IDENTIFIER '{' declaration* '}';
 

src/torque/TorqueBaseListener.h

@@ -318,10 +318,10 @@ class TorqueBaseListener : public TorqueListener {
   void exitMacroDeclaration(
       TorqueParser::MacroDeclarationContext* /*ctx*/) override {}
 
-  void enterConstDeclaration(
-      TorqueParser::ConstDeclarationContext* /*ctx*/) override {}
-  void exitConstDeclaration(
-      TorqueParser::ConstDeclarationContext* /*ctx*/) override {}
+  void enterExternConstDeclaration(
+      TorqueParser::ExternConstDeclarationContext* /*ctx*/) override {}
+  void exitExternConstDeclaration(
+      TorqueParser::ExternConstDeclarationContext* /*ctx*/) override {}
 
   void enterDeclaration(TorqueParser::DeclarationContext* /*ctx*/) override {}
   void exitDeclaration(TorqueParser::DeclarationContext* /*ctx*/) override {}

src/torque/TorqueBaseVisitor.h

@@ -336,8 +336,8 @@ class TorqueBaseVisitor : public TorqueVisitor {
     return visitChildren(ctx);
   }
 
-  antlrcpp::Any visitConstDeclaration(
-      TorqueParser::ConstDeclarationContext* ctx) override {
+  antlrcpp::Any visitExternConstDeclaration(
+      TorqueParser::ExternConstDeclarationContext* ctx) override {
     return visitChildren(ctx);
   }
 

src/torque/TorqueListener.h

@@ -301,10 +301,10 @@ class TorqueListener : public antlr4::tree::ParseTreeListener {
   virtual void exitMacroDeclaration(
       TorqueParser::MacroDeclarationContext* ctx) = 0;
 
-  virtual void enterConstDeclaration(
-      TorqueParser::ConstDeclarationContext* ctx) = 0;
-  virtual void exitConstDeclaration(
-      TorqueParser::ConstDeclarationContext* ctx) = 0;
+  virtual void enterExternConstDeclaration(
+      TorqueParser::ExternConstDeclarationContext* ctx) = 0;
+  virtual void exitExternConstDeclaration(
+      TorqueParser::ExternConstDeclarationContext* ctx) = 0;
 
   virtual void enterDeclaration(TorqueParser::DeclarationContext* ctx) = 0;
   virtual void exitDeclaration(TorqueParser::DeclarationContext* ctx) = 0;

src/torque/TorqueParser.h

@@ -162,7 +162,7 @@ class TorqueParser : public antlr4::Parser {
     RuleBuiltinDeclaration = 63,
     RuleGenericSpecialization = 64,
     RuleMacroDeclaration = 65,
-    RuleConstDeclaration = 66,
+    RuleExternConstDeclaration = 66,
     RuleDeclaration = 67,
     RuleModuleDeclaration = 68,
     RuleFile = 69
@@ -245,7 +245,7 @@ class TorqueParser : public antlr4::Parser {
   class BuiltinDeclarationContext;
   class GenericSpecializationContext;
   class MacroDeclarationContext;
-  class ConstDeclarationContext;
+  class ExternConstDeclarationContext;
   class DeclarationContext;
   class ModuleDeclarationContext;
   class FileContext;
@@ -1397,14 +1397,14 @@ class TorqueParser : public antlr4::Parser {
 
   MacroDeclarationContext* macroDeclaration();
 
-  class ConstDeclarationContext : public antlr4::ParserRuleContext {
+  class ExternConstDeclarationContext : public antlr4::ParserRuleContext {
    public:
-    ConstDeclarationContext(antlr4::ParserRuleContext* parent,
-                            size_t invokingState);
+    ExternConstDeclarationContext(antlr4::ParserRuleContext* parent,
+                                  size_t invokingState);
     size_t getRuleIndex() const override;
     antlr4::tree::TerminalNode* IDENTIFIER();
     TypeContext* type();
-    antlr4::tree::TerminalNode* STRING_LITERAL();
+    GeneratesDeclarationContext* generatesDeclaration();
 
     void enterRule(antlr4::tree::ParseTreeListener* listener) override;
     void exitRule(antlr4::tree::ParseTreeListener* listener) override;
@@ -1412,7 +1412,7 @@ class TorqueParser : public antlr4::Parser {
     antlrcpp::Any accept(antlr4::tree::ParseTreeVisitor* visitor) override;
   };
 
-  ConstDeclarationContext* constDeclaration();
+  ExternConstDeclarationContext* externConstDeclaration();
 
   class DeclarationContext : public antlr4::ParserRuleContext {
    public:
@@ -1426,7 +1426,7 @@ class TorqueParser : public antlr4::Parser {
     ExternalMacroContext* externalMacro();
     ExternalBuiltinContext* externalBuiltin();
     ExternalRuntimeContext* externalRuntime();
-    ConstDeclarationContext* constDeclaration();
+    ExternConstDeclarationContext* externConstDeclaration();
 
     void enterRule(antlr4::tree::ParseTreeListener* listener) override;
     void exitRule(antlr4::tree::ParseTreeListener* listener) override;

src/torque/TorqueVisitor.h

@@ -216,8 +216,8 @@ class TorqueVisitor : public antlr4::tree::AbstractParseTreeVisitor {
   virtual antlrcpp::Any visitMacroDeclaration(
       TorqueParser::MacroDeclarationContext* context) = 0;
 
-  virtual antlrcpp::Any visitConstDeclaration(
-      TorqueParser::ConstDeclarationContext* context) = 0;
+  virtual antlrcpp::Any visitExternConstDeclaration(
+      TorqueParser::ExternConstDeclarationContext* context) = 0;
 
   virtual antlrcpp::Any visitDeclaration(
       TorqueParser::DeclarationContext* context) = 0;

src/torque/ast-generator.cc

@@ -291,13 +291,15 @@ antlrcpp::Any AstGenerator::visitGenericSpecialization(
       context->helperBody()->accept(this).as<Statement*>()}));
 }
 
-antlrcpp::Any AstGenerator::visitConstDeclaration(
-    TorqueParser::ConstDeclarationContext* context) {
-  return implicit_cast<Declaration*>(RegisterNode(new ConstDeclaration{
+antlrcpp::Any AstGenerator::visitExternConstDeclaration(
+    TorqueParser::ExternConstDeclarationContext* context) {
+  return implicit_cast<Declaration*>(RegisterNode(new ExternConstDeclaration{
       Pos(context), context->IDENTIFIER()->getSymbol()->getText(),
       GetType(context->type()),
-      StringLiteralUnquote(
-          context->STRING_LITERAL()->getSymbol()->getText())}));
+      StringLiteralUnquote(context->generatesDeclaration()
+                               ->STRING_LITERAL()
+                               ->getSymbol()
+                               ->getText())}));
 }
 
 antlrcpp::Any AstGenerator::visitTypeDeclaration(

src/torque/ast-generator.h

@@ -44,8 +44,8 @@ class AstGenerator : public TorqueBaseVisitor {
   antlrcpp::Any visitGenericSpecialization(
       TorqueParser::GenericSpecializationContext* context) override;
 
-  antlrcpp::Any visitConstDeclaration(
-      TorqueParser::ConstDeclarationContext* context) override;
+  antlrcpp::Any visitExternConstDeclaration(
+      TorqueParser::ExternConstDeclarationContext* context) override;
 
   antlrcpp::Any visitTypeDeclaration(
       TorqueParser::TypeDeclarationContext* context) override;

src/torque/ast.h

@@ -68,7 +68,7 @@ DECLARE_CONTEXTUAL_VARIABLE(CurrentSourcePosition, SourcePosition)
   V(StandardDeclaration)                  \
   V(GenericDeclaration)                   \
   V(SpecializationDeclaration)            \
-  V(ConstDeclaration)                     \
+  V(ExternConstDeclaration)               \
   V(DefaultModuleDeclaration)             \
   V(ExplicitModuleDeclaration)
 
@@ -664,10 +664,10 @@ struct SpecializationDeclaration : Declaration {
   Statement* body;
 };
 
-struct ConstDeclaration : Declaration {
-  DEFINE_AST_NODE_LEAF_BOILERPLATE(ConstDeclaration)
-  ConstDeclaration(SourcePosition p, std::string n, TypeExpression* t,
-                   std::string l)
+struct ExternConstDeclaration : Declaration {
+  DEFINE_AST_NODE_LEAF_BOILERPLATE(ExternConstDeclaration)
+  ExternConstDeclaration(SourcePosition p, std::string n, TypeExpression* t,
+                         std::string l)
       : Declaration(kKind, p),
         name(std::move(n)),
         type(t),

src/torque/declaration-visitor.h

@@ -108,7 +108,9 @@ class DeclarationVisitor : public FileVisitor {
 
   void Visit(VarDeclarationStatement* stmt);
 
-  void Visit(ConstDeclaration* decl) {
+  void Visit(ExternConstDeclaration* decl) {
+    // TODO(szuend): When module-wide const bindings are available, only
+    //               constexpr types should be allowed here.
     declarations()->DeclareConstant(
         decl->name, declarations()->GetType(decl->type), decl->literal);
   }

src/torque/implementation-visitor.h

@@ -92,7 +92,7 @@ class ImplementationVisitor : public FileVisitor {
   }
   void Visit(TypeDeclaration* decl) {}
   void Visit(TypeAliasDeclaration* decl) {}
-  void Visit(ConstDeclaration* decl) {}
+  void Visit(ExternConstDeclaration* decl) {}
   void Visit(StandardDeclaration* decl);
   void Visit(GenericDeclaration* decl) {}
   void Visit(SpecializationDeclaration* decl);