bytecode-generator.h

// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_INTERPRETER_BYTECODE_GENERATOR_H_
#define V8_INTERPRETER_BYTECODE_GENERATOR_H_

#include "src/ast/ast.h"
#include "src/feedback-vector.h"
#include "src/interpreter/bytecode-array-builder.h"
#include "src/interpreter/bytecode-label.h"
#include "src/interpreter/bytecode-register.h"
#include "src/interpreter/bytecodes.h"

namespace v8 {
namespace internal {

class AstNodeSourceRanges;
class AstStringConstants;
class UnoptimizedCompilationInfo;
enum class SourceRangeKind;

namespace interpreter {

class GlobalDeclarationsBuilder;
class LoopBuilder;
class BlockCoverageBuilder;
class BytecodeJumpTable;

class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
 public:
  explicit BytecodeGenerator(
      UnoptimizedCompilationInfo* info,
      const AstStringConstants* ast_string_constants,
      std::vector<FunctionLiteral*>* eager_inner_literals);

  void GenerateBytecode(uintptr_t stack_limit);
  Handle<BytecodeArray> FinalizeBytecode(Isolate* isolate,
                                         Handle<Script> script);

#define DECLARE_VISIT(type) void Visit##type(type* node);
  AST_NODE_LIST(DECLARE_VISIT)
#undef DECLARE_VISIT

  // Visiting function for declarations list and statements are overridden.
  void VisitDeclarations(Declaration::List* declarations);
  void VisitStatements(const ZonePtrList<Statement>* statments);

 private:
  class ContextScope;
  class ControlScope;
  class ControlScopeForBreakable;
  class ControlScopeForIteration;
  class ControlScopeForTopLevel;
  class ControlScopeForTryCatch;
  class ControlScopeForTryFinally;
  class CurrentScope;
  class ExpressionResultScope;
  class EffectResultScope;
  class FeedbackSlotCache;
  class GlobalDeclarationsBuilder;
  class IteratorRecord;
  class NaryCodeCoverageSlots;
  class RegisterAllocationScope;
  class TestResultScope;
  class ValueResultScope;

  using ToBooleanMode = BytecodeArrayBuilder::ToBooleanMode;

  enum class TestFallthrough { kThen, kElse, kNone };
  enum class TypeHint { kAny, kBoolean, kString };

  void GenerateBytecodeBody();
  void AllocateDeferredConstants(Isolate* isolate, Handle<Script> script);

  DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();

  // Dispatched from VisitBinaryOperation.
  void VisitArithmeticExpression(BinaryOperation* binop);
  void VisitCommaExpression(BinaryOperation* binop);
  void VisitLogicalOrExpression(BinaryOperation* binop);
  void VisitLogicalAndExpression(BinaryOperation* binop);

  // Dispatched from VisitNaryOperation.
  void VisitNaryArithmeticExpression(NaryOperation* expr);
  void VisitNaryCommaExpression(NaryOperation* expr);
  void VisitNaryLogicalOrExpression(NaryOperation* expr);
  void VisitNaryLogicalAndExpression(NaryOperation* expr);

  // Dispatched from VisitUnaryOperation.
  void VisitVoid(UnaryOperation* expr);
  void VisitTypeOf(UnaryOperation* expr);
  void VisitNot(UnaryOperation* expr);
  void VisitDelete(UnaryOperation* expr);

  // Visits a typeof expression for the value on which to perform the typeof.
  void VisitForTypeOfValue(Expression* expr);

  // Used by flow control routines to evaluate loop condition.
  void VisitCondition(Expression* expr);

  // Visit the arguments expressions in |args| and store them in |args_regs|,
  // growing |args_regs| for each argument visited.
  void VisitArguments(const ZonePtrList<Expression>* args,
                      RegisterList* arg_regs);

  // Visit a keyed super property load. The optional
  // |opt_receiver_out| register will have the receiver stored to it
  // if it's a valid register. The loaded value is placed in the
  // accumulator.
  void VisitKeyedSuperPropertyLoad(Property* property,
                                   Register opt_receiver_out);

  // Visit a named super property load. The optional
  // |opt_receiver_out| register will have the receiver stored to it
  // if it's a valid register. The loaded value is placed in the
  // accumulator.
  void VisitNamedSuperPropertyLoad(Property* property,
                                   Register opt_receiver_out);

  void VisitPropertyLoad(Register obj, Property* expr);
  void VisitPropertyLoadForRegister(Register obj, Property* expr,
                                    Register destination);

  void BuildLoadNamedProperty(Property* property, Register object,
                              const AstRawString* name);
  void BuildStoreNamedProperty(Property* property, Register object,
                               const AstRawString* name);

  void BuildVariableLoad(Variable* variable, HoleCheckMode hole_check_mode,
                         TypeofMode typeof_mode = NOT_INSIDE_TYPEOF);
  void BuildVariableLoadForAccumulatorValue(
      Variable* variable, HoleCheckMode hole_check_mode,
      TypeofMode typeof_mode = NOT_INSIDE_TYPEOF);
  void BuildVariableAssignment(
      Variable* variable, Token::Value op, HoleCheckMode hole_check_mode,
      LookupHoistingMode lookup_hoisting_mode = LookupHoistingMode::kNormal);
  void BuildLiteralCompareNil(Token::Value compare_op,
                              BytecodeArrayBuilder::NilValue nil);
  void BuildReturn(int source_position = kNoSourcePosition);
  void BuildAsyncReturn(int source_position = kNoSourcePosition);
  void BuildAsyncGeneratorReturn();
  void BuildReThrow();
  void BuildHoleCheckForVariableAssignment(Variable* variable, Token::Value op);
  void BuildThrowIfHole(Variable* variable);

  // Build jump to targets[value], where
  // start_index <= value < start_index + size.
  void BuildIndexedJump(Register value, size_t start_index, size_t size,
                        ZoneVector<BytecodeLabel>& targets);

  void BuildNewLocalActivationContext();
  void BuildLocalActivationContextInitialization();
  void BuildNewLocalBlockContext(Scope* scope);
  void BuildNewLocalCatchContext(Scope* scope);
  void BuildNewLocalWithContext(Scope* scope);

  void BuildGeneratorPrologue();
  void BuildSuspendPoint(Expression* suspend_expr);

  void BuildAwait(Expression* await_expr);

  void BuildGetIterator(Expression* iterable, IteratorType hint);

  // Create an IteratorRecord with pre-allocated registers holding the next
  // method and iterator object.
  IteratorRecord BuildGetIteratorRecord(Expression* iterable,
                                        Register iterator_next,
                                        Register iterator_object,
                                        IteratorType hint);

  // Create an IteratorRecord allocating new registers to hold the next method
  // and iterator object.
  IteratorRecord BuildGetIteratorRecord(Expression* iterable,
                                        IteratorType hint);
  void BuildIteratorNext(const IteratorRecord& iterator, Register next_result);
  void BuildIteratorClose(const IteratorRecord& iterator,
                          Expression* expr = nullptr);
  void BuildCallIteratorMethod(Register iterator, const AstRawString* method,
                               RegisterList receiver_and_args,
                               BytecodeLabel* if_called,
                               BytecodeLabels* if_notcalled);

  void BuildArrayLiteralSpread(Spread* spread, Register array, Register index,
                               FeedbackSlot index_slot,
                               FeedbackSlot element_slot);
  // Create Array literals. |expr| can be nullptr, but if provided,
  // a boilerplate will be used to create an initial array for elements
  // before the first spread.
  void BuildCreateArrayLiteral(const ZonePtrList<Expression>* elements,
                               ArrayLiteral* expr);
  void BuildCreateObjectLiteral(Register literal, uint8_t flags, size_t entry);
  void AllocateTopLevelRegisters();
  void VisitArgumentsObject(Variable* variable);
  void VisitRestArgumentsArray(Variable* rest);
  void VisitCallSuper(Call* call);
  void BuildClassLiteral(ClassLiteral* expr, Register name);
  void VisitClassLiteral(ClassLiteral* expr, Register name);
  void VisitNewTargetVariable(Variable* variable);
  void VisitThisFunctionVariable(Variable* variable);
  void BuildInstanceMemberInitialization(Register constructor,
                                         Register instance);
  void BuildGeneratorObjectVariableInitialization();
  void VisitBlockDeclarationsAndStatements(Block* stmt);
  void VisitSetHomeObject(Register value, Register home_object,
                          LiteralProperty* property);
  void VisitObjectLiteralAccessor(Register home_object,
                                  ObjectLiteralProperty* property,
                                  Register value_out);
  void VisitForInAssignment(Expression* expr);
  void VisitModuleNamespaceImports();

  // Visit a logical OR/AND within a test context, rewiring the jumps based
  // on the expression values.
  void VisitLogicalTest(Token::Value token, Expression* left, Expression* right,
                        int right_coverage_slot);
  void VisitNaryLogicalTest(Token::Value token, NaryOperation* expr,
                            const NaryCodeCoverageSlots* coverage_slots);
  // Visit a (non-RHS) test for a logical op, which falls through if the test
  // fails or jumps to the appropriate labels if it succeeds.
  void VisitLogicalTestSubExpression(Token::Value token, Expression* expr,
                                     BytecodeLabels* then_labels,
                                     BytecodeLabels* else_labels,
                                     int coverage_slot);

  // Helpers for binary and nary logical op value expressions.
  bool VisitLogicalOrSubExpression(Expression* expr, BytecodeLabels* end_labels,
                                   int coverage_slot);
  bool VisitLogicalAndSubExpression(Expression* expr,
                                    BytecodeLabels* end_labels,
                                    int coverage_slot);

  // Visit the body of a loop iteration.
  void VisitIterationBody(IterationStatement* stmt, LoopBuilder* loop_builder);

  // Visit a statement and switch scopes, the context is in the accumulator.
  void VisitInScope(Statement* stmt, Scope* scope);

  void BuildPushUndefinedIntoRegisterList(RegisterList* reg_list);

  void BuildLoadPropertyKey(LiteralProperty* property, Register out_reg);

  int AllocateBlockCoverageSlotIfEnabled(AstNode* node, SourceRangeKind kind);
  int AllocateNaryBlockCoverageSlotIfEnabled(NaryOperation* node, size_t index);

  void BuildIncrementBlockCoverageCounterIfEnabled(AstNode* node,
                                                   SourceRangeKind kind);
  void BuildIncrementBlockCoverageCounterIfEnabled(int coverage_array_slot);

  void BuildTest(ToBooleanMode mode, BytecodeLabels* then_labels,
                 BytecodeLabels* else_labels, TestFallthrough fallthrough);

  // Visitors for obtaining expression result in the accumulator, in a
  // register, or just getting the effect. Some visitors return a TypeHint which
  // specifies the type of the result of the visited expression.
  TypeHint VisitForAccumulatorValue(Expression* expr);
  void VisitForAccumulatorValueOrTheHole(Expression* expr);
  V8_WARN_UNUSED_RESULT Register VisitForRegisterValue(Expression* expr);
  V8_INLINE void VisitForRegisterValue(Expression* expr, Register destination);
  void VisitAndPushIntoRegisterList(Expression* expr, RegisterList* reg_list);
  void VisitForEffect(Expression* expr);
  void VisitForTest(Expression* expr, BytecodeLabels* then_labels,
                    BytecodeLabels* else_labels, TestFallthrough fallthrough);

  void VisitInSameTestExecutionScope(Expression* expr);

  Register GetRegisterForLocalVariable(Variable* variable);

  // Returns the runtime function id for a store to super for the function's
  // language mode.
  inline Runtime::FunctionId StoreToSuperRuntimeId();
  inline Runtime::FunctionId StoreKeyedToSuperRuntimeId();

  // Returns a cached slot, or create and cache a new slot if one doesn't
  // already exists.
  FeedbackSlot GetCachedLoadGlobalICSlot(TypeofMode typeof_mode,
                                         Variable* variable);
  FeedbackSlot GetCachedStoreGlobalICSlot(LanguageMode language_mode,
                                          Variable* variable);
  FeedbackSlot GetCachedCreateClosureSlot(FunctionLiteral* literal);
  FeedbackSlot GetCachedLoadICSlot(const Expression* expr,
                                   const AstRawString* name);
  FeedbackSlot GetCachedStoreICSlot(const Expression* expr,
                                    const AstRawString* name);
  FeedbackSlot GetDummyCompareICSlot();

  void AddToEagerLiteralsIfEager(FunctionLiteral* literal);

  // Checks if the visited expression is one shot, i.e executed only once. Any
  // expression either in a top level code or an IIFE that is not within a loop
  // is eligible for one shot optimizations.
  inline bool ShouldOptimizeAsOneShot() const;

  static constexpr ToBooleanMode ToBooleanModeFromTypeHint(TypeHint type_hint) {
    return type_hint == TypeHint::kBoolean ? ToBooleanMode::kAlreadyBoolean
                                           : ToBooleanMode::kConvertToBoolean;
  }

  inline Register generator_object() const;

  inline BytecodeArrayBuilder* builder() { return &builder_; }
  inline Zone* zone() const { return zone_; }
  inline DeclarationScope* closure_scope() const { return closure_scope_; }
  inline UnoptimizedCompilationInfo* info() const { return info_; }
  inline const AstStringConstants* ast_string_constants() const {
    return ast_string_constants_;
  }

  inline Scope* current_scope() const { return current_scope_; }
  inline void set_current_scope(Scope* scope) { current_scope_ = scope; }

  inline ControlScope* execution_control() const { return execution_control_; }
  inline void set_execution_control(ControlScope* scope) {
    execution_control_ = scope;
  }
  inline ContextScope* execution_context() const { return execution_context_; }
  inline void set_execution_context(ContextScope* context) {
    execution_context_ = context;
  }
  inline void set_execution_result(ExpressionResultScope* execution_result) {
    execution_result_ = execution_result;
  }
  ExpressionResultScope* execution_result() const { return execution_result_; }
  BytecodeRegisterAllocator* register_allocator() {
    return builder()->register_allocator();
  }

  GlobalDeclarationsBuilder* globals_builder() {
    DCHECK_NOT_NULL(globals_builder_);
    return globals_builder_;
  }
  inline LanguageMode language_mode() const;
  inline FunctionKind function_kind() const;
  inline FeedbackVectorSpec* feedback_spec();
  inline int feedback_index(FeedbackSlot slot) const;

  inline FeedbackSlotCache* feedback_slot_cache() {
    return feedback_slot_cache_;
  }

  inline HandlerTable::CatchPrediction catch_prediction() const {
    return catch_prediction_;
  }
  inline void set_catch_prediction(HandlerTable::CatchPrediction value) {
    catch_prediction_ = value;
  }

  Zone* zone_;
  BytecodeArrayBuilder builder_;
  UnoptimizedCompilationInfo* info_;
  const AstStringConstants* ast_string_constants_;
  DeclarationScope* closure_scope_;
  Scope* current_scope_;

  // External vector of literals to be eagerly compiled.
  std::vector<FunctionLiteral*>* eager_inner_literals_;

  FeedbackSlotCache* feedback_slot_cache_;

  GlobalDeclarationsBuilder* globals_builder_;
  BlockCoverageBuilder* block_coverage_builder_;
  ZoneVector<GlobalDeclarationsBuilder*> global_declarations_;
  ZoneVector<std::pair<FunctionLiteral*, size_t>> function_literals_;
  ZoneVector<std::pair<NativeFunctionLiteral*, size_t>>
      native_function_literals_;
  ZoneVector<std::pair<ObjectLiteral*, size_t>> object_literals_;
  ZoneVector<std::pair<ArrayLiteral*, size_t>> array_literals_;
  ZoneVector<std::pair<ClassLiteral*, size_t>> class_literals_;
  ZoneVector<std::pair<GetTemplateObject*, size_t>> template_objects_;

  ControlScope* execution_control_;
  ContextScope* execution_context_;
  ExpressionResultScope* execution_result_;

  Register incoming_new_target_or_generator_;

  // Dummy feedback slot for compare operations, where we don't care about
  // feedback
  SharedFeedbackSlot dummy_feedback_slot_;

  BytecodeJumpTable* generator_jump_table_;
  int suspend_count_;
  int loop_depth_;

  HandlerTable::CatchPrediction catch_prediction_;
};

}  // namespace interpreter
}  // namespace internal
}  // namespace v8

#endif  // V8_INTERPRETER_BYTECODE_GENERATOR_H_