sdk/runtime/vm/code_descriptors.h

// Copyright (c) 2012, 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 VM_CODE_DESCRIPTORS_H_
#define VM_CODE_DESCRIPTORS_H_

#include "vm/globals.h"
#include "vm/growable_array.h"
#include "vm/object.h"

namespace dart {

class DescriptorList : public ZoneAllocated {
 public:
  struct PcDesc {
    intptr_t pc_offset;        // PC offset value of the descriptor.
    PcDescriptors::Kind kind;  // Descriptor kind (kDeopt, kOther).
    intptr_t node_id;          // AST node id.
    intptr_t token_index;      // Token position in source of PC.
    intptr_t try_index;        // Try block index of PC.
  };

  DescriptorList() : list_() {
  }
  ~DescriptorList() { }

  intptr_t Length() const {
    return list_.length();
  }

  intptr_t PcOffset(int index) const {
    return list_[index].pc_offset;
  }
  PcDescriptors::Kind Kind(int index) const {
    return list_[index].kind;
  }
  intptr_t NodeId(int index) const {
    return list_[index].node_id;
  }
  intptr_t TokenIndex(int index) const {
    return list_[index].token_index;
  }
  intptr_t TryIndex(int index) const {
    return list_[index].try_index;
  }

  void AddDescriptor(PcDescriptors::Kind kind,
                     intptr_t pc_offset,
                     intptr_t node_id,
                     intptr_t token_index,
                     intptr_t try_index);

  RawPcDescriptors* FinalizePcDescriptors(uword entry_point);

 private:
  GrowableArray<struct PcDesc> list_;
  DISALLOW_COPY_AND_ASSIGN(DescriptorList);
};


class StackmapBuilder : public ZoneAllocated {
 public:
  StackmapBuilder() :
      builder_(new BitmapBuilder()),
      code_(Code::ZoneHandle()),
      stack_map_(Stackmap::ZoneHandle()),
      list_(GrowableObjectArray::ZoneHandle(
          GrowableObjectArray::New(Heap::kOld))) { }
  ~StackmapBuilder() { }

  // Gets state of stack slot (object or regular value).
  bool IsSlotObject(intptr_t stack_slot) const {
    ASSERT(builder_ != NULL);
    return builder_->Get(stack_slot);
  }
  // Sets stack slot as containing an object.
  void SetSlotAsObject(intptr_t stack_slot) {
    ASSERT(builder_ != NULL);
    builder_->Set(stack_slot, true);
  }
  // Sets stack slot as containing regular value.
  void SetSlotAsValue(intptr_t stack_slot) {
    ASSERT(builder_ != NULL);
    builder_->Set(stack_slot, false);
  }
  // Sets min..max (inclusive) as stack slots containing objects.
  void SetSlotRangeAsObject(intptr_t min_stack_slot, intptr_t max_stack_slot) {
    ASSERT(builder_ != NULL);
    builder_->SetRange(min_stack_slot, max_stack_slot, true);
  }
  // Sets min..max (inclusive) as stack slots containing regular values.
  void SetSlotRangeAsValue(intptr_t min_stack_slot, intptr_t max_stack_slot) {
    ASSERT(builder_ != NULL);
    builder_->SetRange(min_stack_slot, max_stack_slot, false);
  }

  void AddEntry(intptr_t pc_offset);

  bool Verify();

  RawArray* FinalizeStackmaps(const Code& code);

 private:
  intptr_t Length() const { return list_.Length(); }
  RawStackmap* Map(int index) const;

  BitmapBuilder* builder_;
  Code& code_;
  Stackmap& stack_map_;
  GrowableObjectArray& list_;
  DISALLOW_COPY_AND_ASSIGN(StackmapBuilder);
};


class ExceptionHandlerList : public ZoneAllocated {
 public:
  struct HandlerDesc {
    intptr_t try_index;  // Try block index handled by the handler.
    intptr_t pc_offset;  // Handler PC offset value.
  };

  ExceptionHandlerList() : list_() {}

  intptr_t Length() const {
    return list_.length();
  }

  intptr_t TryIndex(int index) const {
    return list_[index].try_index;
  }
  intptr_t PcOffset(int index) const {
    return list_[index].pc_offset;
  }
  void SetPcOffset(int index, intptr_t handler_pc) {
    list_[index].pc_offset = handler_pc;
  }

  void AddHandler(intptr_t try_index, intptr_t pc_offset) {
    struct HandlerDesc data;
    data.try_index = try_index;
    data.pc_offset = pc_offset;
    list_.Add(data);
  }

  RawExceptionHandlers* FinalizeExceptionHandlers(uword entry_point) {
    intptr_t num_handlers = Length();
    const ExceptionHandlers& handlers =
        ExceptionHandlers::Handle(ExceptionHandlers::New(num_handlers));
    for (intptr_t i = 0; i < num_handlers; i++) {
      handlers.SetHandlerEntry(i, TryIndex(i), (entry_point + PcOffset(i)));
    }
    return handlers.raw();
  }

 private:
  GrowableArray<struct HandlerDesc> list_;
  DISALLOW_COPY_AND_ASSIGN(ExceptionHandlerList);
};

}  // namespace dart

#endif  // VM_CODE_DESCRIPTORS_H_