// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#ifndef RUNTIME_VM_COMPILER_FRONTEND_KERNEL_TO_IL_H_
#define RUNTIME_VM_COMPILER_FRONTEND_KERNEL_TO_IL_H_

#if !defined(DART_PRECOMPILED_RUNTIME)

#include "vm/growable_array.h"
#include "vm/hash_map.h"

#include "vm/compiler/backend/flow_graph.h"
#include "vm/compiler/backend/il.h"
#include "vm/compiler/frontend/base_flow_graph_builder.h"
#include "vm/compiler/frontend/kernel_translation_helper.h"
#include "vm/compiler/frontend/scope_builder.h"

namespace dart {

class InlineExitCollector;

namespace kernel {

class StreamingFlowGraphBuilder;
struct InferredTypeMetadata;
class BreakableBlock;
class CatchBlock;
class FlowGraphBuilder;
class SwitchBlock;
class TryCatchBlock;
class TryFinallyBlock;

struct YieldContinuation {
  Instruction* entry;
  intptr_t try_index;

  YieldContinuation(Instruction* entry, intptr_t try_index)
      : entry(entry), try_index(try_index) {}

  YieldContinuation() : entry(NULL), try_index(kInvalidTryIndex) {}
};

enum class TypeChecksToBuild {
  kCheckAllTypeParameterBounds,
  kCheckNonCovariantTypeParameterBounds,
  kCheckCovariantTypeParameterBounds,
};

// Indicates which form of the unchecked entrypoint we are compiling.
//
// kNone:
//
//   There is no unchecked entrypoint: the unchecked entry is set to NULL in
//   the 'GraphEntryInstr'.
//
// kSeparate:
//
//   The normal and unchecked entrypoint each point to their own versions of
//   the prologue, containing exactly those checks which need to be performed
//   on either side. Both sides jump directly to the body after performing
//   their prologue.
//
// kSharedWithVariable:
//
//   A temporary variable is allocated and initialized to 0 on normal entry
//   and 2 on unchecked entry. Code which should be ommitted on the unchecked
//   entrypoint is made conditional on this variable being equal to 0.
//
enum class UncheckedEntryPointStyle {
  kNone = 0,
  kSeparate = 1,
  kSharedWithVariable = 2,
};

class FlowGraphBuilder : public BaseFlowGraphBuilder {
 public:
  FlowGraphBuilder(ParsedFunction* parsed_function,
                   ZoneGrowableArray<const ICData*>* ic_data_array,
                   ZoneGrowableArray<intptr_t>* context_level_array,
                   InlineExitCollector* exit_collector,
                   bool optimizing,
                   intptr_t osr_id,
                   intptr_t first_block_id = 1,
                   bool inlining_unchecked_entry = false);
  virtual ~FlowGraphBuilder();

  FlowGraph* BuildGraph();

 private:
  BlockEntryInstr* BuildPrologue(BlockEntryInstr* normal_entry,
                                 PrologueInfo* prologue_info);

  FlowGraph* BuildGraphOfMethodExtractor(const Function& method);
  FlowGraph* BuildGraphOfNoSuchMethodDispatcher(const Function& function);
  FlowGraph* BuildGraphOfInvokeFieldDispatcher(const Function& function);

  Fragment NativeFunctionBody(const Function& function,
                              LocalVariable* first_parameter);

  Fragment EnterScope(intptr_t kernel_offset,
                      const LocalScope** scope = nullptr);
  Fragment ExitScope(intptr_t kernel_offset);

  Fragment AdjustContextTo(int depth);

  Fragment PushContext(const LocalScope* scope);
  Fragment PopContext();

  Fragment LoadInstantiatorTypeArguments();
  Fragment LoadFunctionTypeArguments();
  Fragment TranslateInstantiatedTypeArguments(
      const TypeArguments& type_arguments);

  Fragment AllocateObject(TokenPosition position,
                          const Class& klass,
                          intptr_t argument_count);
  Fragment AllocateObject(const Class& klass, const Function& closure_function);
  Fragment CatchBlockEntry(const Array& handler_types,
                           intptr_t handler_index,
                           bool needs_stacktrace,
                           bool is_synthesized);
  Fragment TryCatch(int try_handler_index);
  Fragment CheckStackOverflowInPrologue(TokenPosition position);
  Fragment CloneContext(const GrowableArray<LocalVariable*>& context_variables);

  Fragment InstanceCall(
      TokenPosition position,
      const String& name,
      Token::Kind kind,
      intptr_t type_args_len,
      intptr_t argument_count,
      const Array& argument_names,
      intptr_t checked_argument_count,
      const Function& interface_target,
      const InferredTypeMetadata* result_type = nullptr,
      bool use_unchecked_entry = false,
      const CallSiteAttributesMetadata* call_site_attrs = nullptr);

  Fragment ClosureCall(TokenPosition position,
                       intptr_t type_args_len,
                       intptr_t argument_count,
                       const Array& argument_names,
                       bool use_unchecked_entry = false);

  Fragment RethrowException(TokenPosition position, int catch_try_index);
  Fragment LoadClassId();
  Fragment LoadLocal(LocalVariable* variable);
  Fragment InitStaticField(const Field& field);
  Fragment NativeCall(const String* name, const Function* function);
  Fragment Return(TokenPosition position, bool omit_result_type_check = false);
  Fragment CheckNull(TokenPosition position,
                     LocalVariable* receiver,
                     const String& function_name,
                     bool clear_the_temp = true);
  void SetResultTypeForStaticCall(StaticCallInstr* call,
                                  const Function& target,
                                  intptr_t argument_count,
                                  const InferredTypeMetadata* result_type);
  Fragment StaticCall(TokenPosition position,
                      const Function& target,
                      intptr_t argument_count,
                      ICData::RebindRule rebind_rule);
  Fragment StaticCall(TokenPosition position,
                      const Function& target,
                      intptr_t argument_count,
                      const Array& argument_names,
                      ICData::RebindRule rebind_rule,
                      const InferredTypeMetadata* result_type = NULL,
                      intptr_t type_args_len = 0,
                      bool use_unchecked_entry = false);
  Fragment StringInterpolate(TokenPosition position);
  Fragment StringInterpolateSingle(TokenPosition position);
  Fragment ThrowTypeError();
  Fragment ThrowNoSuchMethodError();
  Fragment BuildImplicitClosureCreation(const Function& target);

  Fragment EvaluateAssertion();
  Fragment CheckVariableTypeInCheckedMode(const AbstractType& dst_type,
                                          const String& name_symbol);
  Fragment CheckBoolean(TokenPosition position);
  Fragment CheckAssignable(
      const AbstractType& dst_type,
      const String& dst_name,
      AssertAssignableInstr::Kind kind = AssertAssignableInstr::kUnknown);

  Fragment AssertAssignable(
      TokenPosition position,
      const AbstractType& dst_type,
      const String& dst_name,
      AssertAssignableInstr::Kind kind = AssertAssignableInstr::kUnknown);
  Fragment AssertSubtype(TokenPosition position,
                         const AbstractType& sub_type,
                         const AbstractType& super_type,
                         const String& dst_name);

  bool NeedsDebugStepCheck(const Function& function, TokenPosition position);
  bool NeedsDebugStepCheck(Value* value, TokenPosition position);
  Fragment DebugStepCheck(TokenPosition position);

  LocalVariable* LookupVariable(intptr_t kernel_offset);

  // Build argument type checks for the current function.
  // ParsedFunction should have the following information:
  //  - is_forwarding_stub()
  //  - forwarding_stub_super_target()
  // Scope should be populated with parameter variables including
  //  - needs_type_check()
  //  - is_explicit_covariant_parameter()
  void BuildArgumentTypeChecks(TypeChecksToBuild mode,
                               Fragment* explicit_checks,
                               Fragment* implicit_checks,
                               Fragment* implicit_redefinitions);

  // Builds flow graph for noSuchMethod forwarder.
  //
  // If throw_no_such_method_error is set to true, an
  // instance of NoSuchMethodError is thrown. Otherwise, the instance
  // noSuchMethod is called.
  //
  // ParsedFunction should have the following information:
  //  - default_parameter_values()
  //  - is_forwarding_stub()
  //  - forwarding_stub_super_target()
  //
  // Scope should be populated with parameter variables including
  //  - needs_type_check()
  //  - is_explicit_covariant_parameter()
  //
  FlowGraph* BuildGraphOfNoSuchMethodForwarder(
      const Function& function,
      bool is_implicit_closure_function,
      bool throw_no_such_method_error);

  // If no type arguments are passed to a generic function, we need to fill the
  // type arguments in with the default types stored on the TypeParameter nodes
  // in Kernel.
  //
  // ParsedFunction should have the following information:
  //  - DefaultFunctionTypeArguments()
  //  - function_type_arguments()
  Fragment BuildDefaultTypeHandling(const Function& function);

  Fragment BuildEntryPointsIntrospection();
  FunctionEntryInstr* BuildSharedUncheckedEntryPoint(
      Fragment prologue_from_normal_entry,
      Fragment skippable_checks,
      Fragment redefinitions_if_skipped,
      Fragment body);
  FunctionEntryInstr* BuildSeparateUncheckedEntryPoint(
      BlockEntryInstr* normal_entry,
      Fragment normal_prologue,
      Fragment extra_prologue,
      Fragment shared_prologue,
      Fragment body);
  void RecordUncheckedEntryPoint(FunctionEntryInstr* extra_entry);

  // Builds flow graph for implicit closure function (tear-off).
  //
  // ParsedFunction should have the following information:
  //  - default_parameter_values()
  //  - is_forwarding_stub()
  //  - forwarding_stub_super_target()
  //
  // Scope should be populated with parameter variables including
  //  - needs_type_check()
  //  - is_explicit_covariant_parameter()
  //
  FlowGraph* BuildGraphOfImplicitClosureFunction(const Function& function);

  TranslationHelper translation_helper_;
  Thread* thread_;
  Zone* zone_;

  ParsedFunction* parsed_function_;
  const bool optimizing_;
  ZoneGrowableArray<const ICData*>& ic_data_array_;

  intptr_t next_function_id_;
  intptr_t AllocateFunctionId() { return next_function_id_++; }

  intptr_t loop_depth_;
  intptr_t try_depth_;
  intptr_t catch_depth_;
  intptr_t for_in_depth_;

  GraphEntryInstr* graph_entry_;

  ScopeBuildingResult* scopes_;

  GrowableArray<YieldContinuation> yield_continuations_;

  LocalVariable* CurrentException() {
    return scopes_->exception_variables[catch_depth_ - 1];
  }
  LocalVariable* CurrentStackTrace() {
    return scopes_->stack_trace_variables[catch_depth_ - 1];
  }
  LocalVariable* CurrentRawException() {
    return scopes_->raw_exception_variables[catch_depth_ - 1];
  }
  LocalVariable* CurrentRawStackTrace() {
    return scopes_->raw_stack_trace_variables[catch_depth_ - 1];
  }
  LocalVariable* CurrentCatchContext() {
    return scopes_->catch_context_variables[try_depth_];
  }

  TryCatchBlock* CurrentTryCatchBlock() const { return try_catch_block_; }

  void SetCurrentTryCatchBlock(TryCatchBlock* try_catch_block);

  // A chained list of breakable blocks. Chaining and lookup is done by the
  // [BreakableBlock] class.
  BreakableBlock* breakable_block_;

  // A chained list of switch blocks. Chaining and lookup is done by the
  // [SwitchBlock] class.
  SwitchBlock* switch_block_;

  // A chained list of try-catch blocks. Chaining and lookup is done by the
  // [TryCatchBlock] class.
  TryCatchBlock* try_catch_block_;

  // A chained list of try-finally blocks. Chaining and lookup is done by the
  // [TryFinallyBlock] class.
  TryFinallyBlock* try_finally_block_;

  // A chained list of catch blocks. Chaining and lookup is done by the
  // [CatchBlock] class.
  CatchBlock* catch_block_;

  ActiveClass active_class_;

  friend class BreakableBlock;
  friend class CatchBlock;
  friend class ConstantEvaluator;
  friend class ProgramState;
  friend class StreamingFlowGraphBuilder;
  friend class SwitchBlock;
  friend class TryCatchBlock;
  friend class TryFinallyBlock;

  DISALLOW_COPY_AND_ASSIGN(FlowGraphBuilder);
};

// Convenience class to save/restore program state.
// This snapshot denotes a partial state of the flow
// grap builder that is needed when recursing into
// the statements and expressions of a finalizer block.
class ProgramState {
 public:
  ProgramState(BreakableBlock* breakable_block,
               SwitchBlock* switch_block,
               intptr_t loop_depth,
               intptr_t for_in_depth,
               intptr_t try_depth,
               intptr_t catch_depth)
      : breakable_block_(breakable_block),
        switch_block_(switch_block),
        loop_depth_(loop_depth),
        for_in_depth_(for_in_depth),
        try_depth_(try_depth),
        catch_depth_(catch_depth) {}

  void assignTo(FlowGraphBuilder* builder) const {
    builder->breakable_block_ = breakable_block_;
    builder->switch_block_ = switch_block_;
    builder->loop_depth_ = loop_depth_;
    builder->for_in_depth_ = for_in_depth_;
    builder->try_depth_ = try_depth_;
    builder->catch_depth_ = catch_depth_;
  }

 private:
  BreakableBlock* const breakable_block_;
  SwitchBlock* const switch_block_;
  const intptr_t loop_depth_;
  const intptr_t for_in_depth_;
  const intptr_t try_depth_;
  const intptr_t catch_depth_;
};

class SwitchBlock {
 public:
  SwitchBlock(FlowGraphBuilder* builder, intptr_t case_count)
      : builder_(builder),
        outer_(builder->switch_block_),
        outer_finally_(builder->try_finally_block_),
        case_count_(case_count),
        context_depth_(builder->context_depth_),
        try_index_(builder->CurrentTryIndex()) {
    builder_->switch_block_ = this;
    if (outer_ != NULL) {
      depth_ = outer_->depth_ + outer_->case_count_;
    } else {
      depth_ = 0;
    }
  }
  ~SwitchBlock() { builder_->switch_block_ = outer_; }

  bool HadJumper(intptr_t case_num) {
    return destinations_.Lookup(case_num) != NULL;
  }

  // Get destination via absolute target number (i.e. the correct destination
  // is not necessarily in this block).
  JoinEntryInstr* Destination(intptr_t target_index,
                              TryFinallyBlock** outer_finally = NULL,
                              intptr_t* context_depth = NULL) {
    // Verify consistency of program state.
    ASSERT(builder_->switch_block_ == this);
    // Find corresponding destination.
    SwitchBlock* block = this;
    while (block->depth_ > target_index) {
      block = block->outer_;
      ASSERT(block != nullptr);
    }

    // Set the outer finally block.
    if (outer_finally != NULL) {
      *outer_finally = block->outer_finally_;
      *context_depth = block->context_depth_;
    }

    // Ensure there's [JoinEntryInstr] for that [SwitchCase].
    return block->EnsureDestination(target_index - block->depth_);
  }

  // Get destination via relative target number (i.e. relative to this block,
  // 0 is first case in this block etc).
  JoinEntryInstr* DestinationDirect(intptr_t case_num,
                                    TryFinallyBlock** outer_finally = NULL,
                                    intptr_t* context_depth = NULL) {
    // Set the outer finally block.
    if (outer_finally != NULL) {
      *outer_finally = outer_finally_;
      *context_depth = context_depth_;
    }

    // Ensure there's [JoinEntryInstr] for that [SwitchCase].
    return EnsureDestination(case_num);
  }

 private:
  JoinEntryInstr* EnsureDestination(intptr_t case_num) {
    JoinEntryInstr* cached_inst = destinations_.Lookup(case_num);
    if (cached_inst == NULL) {
      JoinEntryInstr* inst = builder_->BuildJoinEntry(try_index_);
      destinations_.Insert(case_num, inst);
      return inst;
    }
    return cached_inst;
  }

  FlowGraphBuilder* builder_;
  SwitchBlock* outer_;

  IntMap<JoinEntryInstr*> destinations_;

  TryFinallyBlock* outer_finally_;
  intptr_t case_count_;
  intptr_t depth_;
  intptr_t context_depth_;
  intptr_t try_index_;
};

class TryCatchBlock {
 public:
  explicit TryCatchBlock(FlowGraphBuilder* builder,
                         intptr_t try_handler_index = -1)
      : builder_(builder),
        outer_(builder->CurrentTryCatchBlock()),
        try_index_(try_handler_index == -1 ? builder->AllocateTryIndex()
                                           : try_handler_index) {
    builder->SetCurrentTryCatchBlock(this);
  }

  ~TryCatchBlock() { builder_->SetCurrentTryCatchBlock(outer_); }

  intptr_t try_index() { return try_index_; }
  TryCatchBlock* outer() const { return outer_; }

 private:
  FlowGraphBuilder* const builder_;
  TryCatchBlock* const outer_;
  intptr_t const try_index_;

  DISALLOW_COPY_AND_ASSIGN(TryCatchBlock);
};

class TryFinallyBlock {
 public:
  TryFinallyBlock(FlowGraphBuilder* builder, intptr_t finalizer_kernel_offset)
      : builder_(builder),
        outer_(builder->try_finally_block_),
        finalizer_kernel_offset_(finalizer_kernel_offset),
        context_depth_(builder->context_depth_),
        try_index_(builder_->CurrentTryIndex()),
        // Finalizers are executed outside of the try block hence
        // try depth of finalizers are one less than current try
        // depth. For others, program state is snapshot of current.
        state_(builder_->breakable_block_,
               builder_->switch_block_,
               builder_->loop_depth_,
               builder_->for_in_depth_,
               builder_->try_depth_ - 1,
               builder_->catch_depth_) {
    builder_->try_finally_block_ = this;
  }
  ~TryFinallyBlock() { builder_->try_finally_block_ = outer_; }

  TryFinallyBlock* outer() const { return outer_; }
  intptr_t finalizer_kernel_offset() const { return finalizer_kernel_offset_; }
  intptr_t context_depth() const { return context_depth_; }
  intptr_t try_index() const { return try_index_; }
  const ProgramState& state() const { return state_; }

 private:
  FlowGraphBuilder* const builder_;
  TryFinallyBlock* const outer_;
  const intptr_t finalizer_kernel_offset_;
  const intptr_t context_depth_;
  const intptr_t try_index_;
  const ProgramState state_;

  DISALLOW_COPY_AND_ASSIGN(TryFinallyBlock);
};

class BreakableBlock {
 public:
  explicit BreakableBlock(FlowGraphBuilder* builder)
      : builder_(builder),
        outer_(builder->breakable_block_),
        destination_(NULL),
        outer_finally_(builder->try_finally_block_),
        context_depth_(builder->context_depth_),
        try_index_(builder->CurrentTryIndex()) {
    if (builder_->breakable_block_ == NULL) {
      index_ = 0;
    } else {
      index_ = builder_->breakable_block_->index_ + 1;
    }
    builder_->breakable_block_ = this;
  }
  ~BreakableBlock() { builder_->breakable_block_ = outer_; }

  bool HadJumper() { return destination_ != NULL; }

  JoinEntryInstr* destination() { return destination_; }

  JoinEntryInstr* BreakDestination(intptr_t label_index,
                                   TryFinallyBlock** outer_finally,
                                   intptr_t* context_depth) {
    // Verify consistency of program state.
    ASSERT(builder_->breakable_block_ == this);
    // Find corresponding destination.
    BreakableBlock* block = this;
    while (block->index_ != label_index) {
      block = block->outer_;
      ASSERT(block != nullptr);
    }
    *outer_finally = block->outer_finally_;
    *context_depth = block->context_depth_;
    return block->EnsureDestination();
  }

 private:
  JoinEntryInstr* EnsureDestination() {
    if (destination_ == NULL) {
      destination_ = builder_->BuildJoinEntry(try_index_);
    }
    return destination_;
  }

  FlowGraphBuilder* builder_;
  intptr_t index_;
  BreakableBlock* outer_;
  JoinEntryInstr* destination_;
  TryFinallyBlock* outer_finally_;
  intptr_t context_depth_;
  intptr_t try_index_;

  DISALLOW_COPY_AND_ASSIGN(BreakableBlock);
};

class CatchBlock {
 public:
  CatchBlock(FlowGraphBuilder* builder,
             LocalVariable* exception_var,
             LocalVariable* stack_trace_var,
             intptr_t catch_try_index)
      : builder_(builder),
        outer_(builder->catch_block_),
        exception_var_(exception_var),
        stack_trace_var_(stack_trace_var),
        catch_try_index_(catch_try_index) {
    builder_->catch_block_ = this;
  }
  ~CatchBlock() { builder_->catch_block_ = outer_; }

  LocalVariable* exception_var() { return exception_var_; }
  LocalVariable* stack_trace_var() { return stack_trace_var_; }
  intptr_t catch_try_index() { return catch_try_index_; }

 private:
  FlowGraphBuilder* builder_;
  CatchBlock* outer_;
  LocalVariable* exception_var_;
  LocalVariable* stack_trace_var_;
  intptr_t catch_try_index_;

  DISALLOW_COPY_AND_ASSIGN(CatchBlock);
};

}  // namespace kernel
}  // namespace dart

#endif  // !defined(DART_PRECOMPILED_RUNTIME)
#endif  // RUNTIME_VM_COMPILER_FRONTEND_KERNEL_TO_IL_H_