Split generic code and example. Add RTTI, arrays and such.
This commit is contained in:
Nikolay Igotti
@@ -10,4 +10,7 @@ clean:
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placer: placer.o
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place.o: placer.cc layout.h
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$(CXX) $(CXXFLAGS) -c placer.cc
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.PHONY: all run clean
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@@ -0,0 +1,407 @@
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#pragma once
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <cassert>
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#include <cstddef>
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#include <initializer_list>
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class Container;
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class TypeInfo;
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// Header of every object. Now contains direct references, will contain
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// offsets in real translated code.
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struct ObjHeader {
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Container* container_;
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const TypeInfo* type_info_;
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};
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// Header of value type array objects.
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struct ArrayHeader : public ObjHeader {
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int count_;
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};
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// Class representing placement container. Container is used for reference counting,
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// and it is assumed that objects with related placement will share container. Only
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// whole container can be freed, individual objects are not taken into account.
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class Container {
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private:
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// Data where everything is being stored.
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uint8_t* data_;
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// Current allocation limit. As objects never freed, we can have rather simple
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// allocation algorithm.
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uint8_t* current_;
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// Total size of the container.
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int size_;
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// Reference counter of container.
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int ref_count_;
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public:
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Container(int size)
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: size_(size), ref_count_(1) {
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data_ = reinterpret_cast<uint8_t*>(calloc(size_, 1));
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current_ = data_;
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}
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~Container() {
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assert(ref_count_ == 0);
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free(data_);
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}
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// Allocation function.
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void* Place(int size) {
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if (current_ + size > data_ + size_) {
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return nullptr;
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}
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void* result = current_;
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current_ += size;
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return result;
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}
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// Place individual object in this container.
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ObjHeader* PlaceObject(const TypeInfo* type_info);
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// Places an array of certain type in this container. Note that array_type_info
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// is type infor for an array, not for an individual element.
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ArrayHeader* PlaceArray(const TypeInfo* array_type_info, int count);
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// Increment reference counter associated with container.
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void AddRef() {
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if (data_) {
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// printf("addref %d\n", ref_count_);
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ref_count_++;
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}
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}
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// Decrement reference counter associated with container.
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// For objects whith tricky lifetime (such as ones shared between threads objects)
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// individual container per object shall be created. As an alternative, such objects
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// could be evacuated from short-lived containers.
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void Release() {
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if (data_) {
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// printf("release %d\n", ref_count_);
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ref_count_--;
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}
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}
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// Dispose whole container ignoring non-zero refcount. Use with care.
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void Dispose() {
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ref_count_ = 0;
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free(data_);
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data_ = nullptr;
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current_ = nullptr;
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}
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};
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// Raw reference to data, meaning T*, invented only for cleaness of intentions.
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template <class T>
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class RawRef {
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private:
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T* ptr_;
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public:
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RawRef(T* ptr) : ptr_(ptr) {}
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const T& get() const { return *ptr_; }
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void set(const T& value) { *ptr_ = value; }
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};
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// Object reference, adds reference counting in container and type information.
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class AnyObjRef {
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protected:
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ObjHeader* ptr_;
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explicit AnyObjRef(ObjHeader* ptr) : ptr_(ptr) {
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if (ptr_) {
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container()->AddRef();
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}
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}
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public:
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~AnyObjRef() {
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if (ptr_) {
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container()->Release();
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}
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}
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Container* container() const {
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return ptr_->container_;
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}
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const TypeInfo* type_info() const {
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return ptr_->type_info_;
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}
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// Accesses raw data inside object specified by offset. Typing by M is optional and
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// will be replaced by translator typing.
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template<typename M, int offset>
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RawRef<M> at() const {
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return RawRef<M>(
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reinterpret_cast<M*>(reinterpret_cast<uint8_t*>(any_ref()) + offset));
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}
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// Assign reference to certain object. Releases currently held object in its container and
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// adds reference to container storing given object.
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void Assign(const AnyObjRef& other) {
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// TODO: optimize for an important case where containers match?
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if (ptr_) {
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container()->Release();
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}
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ptr_ = other.ptr_;
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if (ptr_) {
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container()->AddRef();
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}
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}
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// Returns pointer to the raw data referred by this reference.
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uint8_t* any_ref() const {
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if (!ptr_) return nullptr;
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return reinterpret_cast<uint8_t*>(ptr_) + sizeof(ObjHeader);
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}
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// Uses pointer stored in object's field to create a reference to that object.
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AnyObjRef any_obj_at(int offset) const {
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assert(ptr_);
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return AnyObjRef(*reinterpret_cast<ObjHeader**>(any_ref() + offset));
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}
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// Checks if given reference has null value.
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bool null() const { return ptr_ == nullptr; }
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};
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// Returns typeinfo for array of type T. Specialize for types which are allowed as array elements.
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template <typename T>
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const TypeInfo* GetArrayTypeInfo() {
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return nullptr;
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}
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// Reference to an object with particular memory layout specified by T.
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// In real runtime will be compile time only type, on runtime all references are
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// AnyObjRef.
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template <class T>
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class ObjRef : public AnyObjRef {
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private:
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explicit ObjRef(ObjHeader* ptr) : AnyObjRef(ptr) {}
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// Reference to raw data in owned class.
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T* ref() const {
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if (!ptr_) return nullptr;
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return reinterpret_cast<T*>(any_ref());
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}
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template <typename T1> friend class ArrayRef;
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public:
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// Assigns reference, compile time type-safe.
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ObjRef(const ObjRef& other) : AnyObjRef(nullptr) {
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Assign(other);
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}
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ObjRef& operator=(const ObjRef& other) {
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Assign(other);
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return *this;
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}
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void Assign(const ObjRef<T>& other) {
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AnyObjRef::Assign(other);
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}
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// Copies data bits to another place, reference counting is properly accounted for
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// by consulting type information.
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void CopyTo(ObjRef<T> other) const;
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// Clones object to given container.
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ObjRef<T> Clone(Container* container) {
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ObjRef<T> result = Alloc(container);
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CopyTo(result);
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return result;
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}
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// Takes typed object reference at offset.
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template<typename M, int offset>
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ObjRef<M> obj_at() const {
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return ObjRef<M>(reinterpret_cast<M*>(any_ref() + offset));
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}
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// Allocates properly typed object in container.
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static ObjRef<T> Alloc(Container* container) {
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return ObjRef<T>(container->PlaceObject(T::GetTypeInfo()));
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}
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};
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// This is an array of value types only, no object references here.
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template <class T>
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class ArrayRef : public AnyObjRef {
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protected:
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explicit ArrayRef(ArrayHeader* ptr) : AnyObjRef(ptr) {}
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ArrayHeader* header() { return reinterpret_cast<ArrayHeader*>(ptr_); }
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public:
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static ArrayRef<T> Alloc(Container* container, int count) {
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auto result = ArrayRef<T>(container->PlaceArray(GetArrayTypeInfo<T>(), count));
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result.header()->count_ = count;
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return result;
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}
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RawRef<T> element_at(int index) const {
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assert(header() && index >= 0 && index < header()->count_);
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return reinterpret_cast<T*>(any_ref() + index * sizeof(T));
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}
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};
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// All names in system are stored as hashes (or maybe, for debug builds,
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// as pointers to uniqued C strings containing names?).
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typedef uint64_t name_hash_t;
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// An element of sorted by hash in-place array representing methods.
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struct MethodTableRecord {
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name_hash_t name_signature_;
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void* method_entry_point_;
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};
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// An element of sorted by hash in-place array representing field offsets.
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struct FieldTableRecord {
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name_hash_t name_signature_;
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int field_offset_;
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};
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// This class represents runtime type information and by itself is compile time
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// constant.
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class TypeInfo {
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private:
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name_hash_t name_;
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int size_;
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const TypeInfo* super_type_;
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const int* obj_offsets_;
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int obj_offsets_count_;
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TypeInfo* const* implemented_interfaces_;
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int implemented_interfaces_count_;
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const MethodTableRecord* methods_;
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int methods_count_;
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const FieldTableRecord* fields_;
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int fields_count_;
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public:
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TypeInfo(name_hash_t name, int size, const TypeInfo* super_type,
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std::initializer_list<int> obj_offsets,
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std::initializer_list<TypeInfo*> implemented_interfaces,
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std::initializer_list<MethodTableRecord> methods,
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std::initializer_list<FieldTableRecord> fields)
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: name_(name), size_(size), super_type_(super_type),
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obj_offsets_(obj_offsets.begin()), obj_offsets_count_(obj_offsets.size()),
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implemented_interfaces_(implemented_interfaces.begin()),
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implemented_interfaces_count_(implemented_interfaces.size()),
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methods_(methods.begin()), methods_count_(methods.size()),
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fields_(fields.begin()), fields_count_(fields.size()) {}
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name_hash_t name() const { return name_; }
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int size() const { return size_; }
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const TypeInfo* super_type() const { return super_type_; }
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const int* obj_offsets(int* count) const {
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*count = obj_offsets_count_;
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return obj_offsets_;
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}
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};
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inline ObjHeader* Container::PlaceObject(const TypeInfo* type_info) {
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int size = type_info->size() + sizeof(ObjHeader);
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ObjHeader* result = reinterpret_cast<ObjHeader*>(Place(size));
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if (!result) {
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return nullptr;
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}
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result->container_ = this;
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result->type_info_ = type_info;
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return result;
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}
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inline ArrayHeader* Container::PlaceArray(const TypeInfo* type_info, int count) {
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int size = sizeof(ArrayHeader) + type_info->size() * count;
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ArrayHeader* result = reinterpret_cast<ArrayHeader*>(Place(size));
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if (!result) {
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return nullptr;
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}
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result->container_ = this;
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result->type_info_ = type_info;
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result->count_ = count;
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return result;
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}
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template <typename T>
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inline void ObjRef<T>::CopyTo(ObjRef<T> other) const {
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assert(!other.null());
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assert(other.type_info()->size() == type_info()->size());
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if (ref()) {
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memcpy(other.ref(), ref(), sizeof(T));
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int obj_offsets_count = 0;
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const int* obj_offsets = ptr_->type_info_->obj_offsets(&obj_offsets_count);
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for (int i = 0; i < obj_offsets_count; ++i) {
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AnyObjRef any = other.any_obj_at(obj_offsets[i]);
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if (!any.null()) {
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any.container()->AddRef();
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}
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}
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} else {
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// TODO: shall we do anything if copy from/to null?
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}
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}
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// This is magic for compile-time hash computation. Not needed in real translator.
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static constexpr uint32_t crc_table[256] = {
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0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
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0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
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0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
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0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
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0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
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0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
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0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
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0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
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0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
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0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
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0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
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0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
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0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
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0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
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0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
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0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
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0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
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0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
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0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
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0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
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0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
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0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
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0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
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0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
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0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
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0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
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0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
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0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
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0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
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0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
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0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
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0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
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0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
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0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
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0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
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0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
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0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
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0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
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0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
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0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
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0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
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0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
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0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
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};
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template<size_t idx>
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constexpr uint32_t crc32(const char * str) {
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return (crc32<idx-1>(str) >> 8) ^ crc_table[(crc32<idx-1>(str) ^ str[idx]) & 0x000000FF];
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}
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|
||||
// Stop-recursion function
|
||||
template<>
|
||||
constexpr uint32_t crc32<size_t(-1)>(const char * str) {
|
||||
return 0xFFFFFFFF;
|
||||
}
|
||||
|
||||
constexpr name_hash_t NameHash(const char* name) {
|
||||
return crc32<sizeof(name) - 2>(name) ^ 0xFFFFFFFF;
|
||||
}
|
||||
+11
-174
@@ -6,187 +6,24 @@
|
||||
#include <cassert>
|
||||
#include <cstddef>
|
||||
|
||||
class Container {
|
||||
private:
|
||||
uint8_t* data_;
|
||||
uint8_t* current_;
|
||||
int size_;
|
||||
int ref_count_;
|
||||
|
||||
public:
|
||||
Container(int size)
|
||||
: size_(size), ref_count_(1) {
|
||||
data_ = reinterpret_cast<uint8_t*>(calloc(size_, 1));
|
||||
current_ = data_;
|
||||
}
|
||||
|
||||
~Container() {
|
||||
assert(ref_count_ == 0);
|
||||
free(data_);
|
||||
}
|
||||
|
||||
void* Place(int size) {
|
||||
size += sizeof(Container*);
|
||||
if (current_ + size > data_ + size_) {
|
||||
return nullptr;
|
||||
}
|
||||
Container** result = reinterpret_cast<Container**>(current_);
|
||||
*result = this;
|
||||
current_ += size;
|
||||
return result;
|
||||
}
|
||||
|
||||
void AddRef() {
|
||||
if (data_) {
|
||||
//printf("addref %d\n", ref_count_);
|
||||
ref_count_++;
|
||||
}
|
||||
}
|
||||
|
||||
void Release() {
|
||||
if (data_) {
|
||||
// printf("release %d\n", ref_count_);
|
||||
ref_count_--;
|
||||
}
|
||||
}
|
||||
|
||||
void Dispose() {
|
||||
// Destroy container ignoring non-zero refcount. Use with care.
|
||||
ref_count_ = 0;
|
||||
free(data_);
|
||||
data_ = nullptr;
|
||||
current_ = nullptr;
|
||||
}
|
||||
};
|
||||
|
||||
// Raw reference to data, meaning T*, invented only for cleaness of intentions.
|
||||
template <class T>
|
||||
class RawRef {
|
||||
private:
|
||||
T* ptr_;
|
||||
public:
|
||||
RawRef(T* ptr) : ptr_(ptr) {}
|
||||
const T& get() const { return *ptr_; }
|
||||
void set(const T& value) { *ptr_ = value; }
|
||||
};
|
||||
|
||||
class AnyObjRef {
|
||||
protected:
|
||||
void* ptr_;
|
||||
|
||||
explicit AnyObjRef(void* ptr) : ptr_(ptr) {
|
||||
if (ptr_) {
|
||||
container()->AddRef();
|
||||
}
|
||||
}
|
||||
|
||||
public:
|
||||
~AnyObjRef() {
|
||||
if (ptr_) {
|
||||
container()->Release();
|
||||
}
|
||||
}
|
||||
|
||||
Container* container() {
|
||||
return *reinterpret_cast<Container**>(ptr_);
|
||||
}
|
||||
|
||||
template<typename M, int offset>
|
||||
RawRef<M> at() const {
|
||||
return RawRef<M>(
|
||||
reinterpret_cast<M*>(reinterpret_cast<uint8_t*>(any_ref()) + offset));
|
||||
}
|
||||
|
||||
void Assign(const AnyObjRef& other) {
|
||||
// TODO: optimize for an important case where containers match?
|
||||
if (ptr_) {
|
||||
container()->Release();
|
||||
}
|
||||
ptr_ = other.ptr_;
|
||||
if (ptr_) {
|
||||
container()->AddRef();
|
||||
}
|
||||
}
|
||||
|
||||
uint8_t* any_ref() const {
|
||||
if (!ptr_) return nullptr;
|
||||
return reinterpret_cast<uint8_t*>(ptr_) + sizeof(Container*);
|
||||
}
|
||||
|
||||
AnyObjRef any_obj_at(int offset) const {
|
||||
assert(ptr_);
|
||||
return AnyObjRef(*reinterpret_cast<void**>(any_ref() + offset));
|
||||
}
|
||||
|
||||
bool null() const { return ptr_ == nullptr; }
|
||||
};
|
||||
|
||||
// Object reference, adds reference counting in container.
|
||||
template <class T>
|
||||
class ObjRef : public AnyObjRef {
|
||||
private:
|
||||
explicit ObjRef(void* ptr) : AnyObjRef(ptr) {}
|
||||
|
||||
T* ref() const {
|
||||
if (!ptr_) return nullptr;
|
||||
return reinterpret_cast<T*>(any_ref());
|
||||
}
|
||||
|
||||
public:
|
||||
ObjRef(const ObjRef& other) : AnyObjRef(nullptr) {
|
||||
Assign(other);
|
||||
}
|
||||
ObjRef& operator=(const ObjRef& other) {
|
||||
Assign(other);
|
||||
return *this;
|
||||
}
|
||||
|
||||
void Assign(const ObjRef<T>& other) {
|
||||
AnyObjRef::Assign(other);
|
||||
}
|
||||
|
||||
void CopyTo(ObjRef<T> other) const {
|
||||
assert(!other.null());
|
||||
if (ref()) {
|
||||
memcpy(other.ref(), ref(), sizeof(T));
|
||||
for (int i = 0; i < sizeof(T::obj_offsets) / sizeof(T::obj_offsets[0]); ++i) {
|
||||
AnyObjRef any = other.any_obj_at(T::obj_offsets[i]);
|
||||
if (!any.null()) {
|
||||
any.container()->AddRef();
|
||||
}
|
||||
}
|
||||
} else {
|
||||
// TODO: shall we do anything if copy from/to null?
|
||||
}
|
||||
}
|
||||
|
||||
ObjRef<T> Clone(Container* container) {
|
||||
ObjRef<T> result = Alloc(container);
|
||||
CopyTo(result);
|
||||
return result;
|
||||
}
|
||||
|
||||
template<typename M, int offset>
|
||||
ObjRef<M> obj_at() const {
|
||||
return ObjRef<M>(
|
||||
reinterpret_cast<M*>(any_ref() + offset));
|
||||
}
|
||||
|
||||
static ObjRef<T> Alloc(Container* container) {
|
||||
return ObjRef<T>(container->Place(sizeof(T)));
|
||||
}
|
||||
};
|
||||
#include "layout.h"
|
||||
|
||||
struct List {
|
||||
static const TypeInfo* GetTypeInfo() {
|
||||
const static TypeInfo result = {
|
||||
NameHash("List"), sizeof(List), nullptr, {0, 8},
|
||||
{}, // implemented interfaces
|
||||
{}, // methods
|
||||
{} // fields
|
||||
};
|
||||
return &result;
|
||||
}
|
||||
|
||||
ObjRef<List> next_;
|
||||
ObjRef<List> prev_;
|
||||
int data_;
|
||||
// Object offsets in the class, needed for CopyTo() operation to update refs and for GC.
|
||||
static constexpr int obj_offsets[] = { 0 /* =offsetof(struct List, next_) */, 8 /* =offsetof(struct List, prev_) */ };
|
||||
};
|
||||
|
||||
constexpr int List::obj_offsets[];
|
||||
|
||||
void UpdateElement(ObjRef<List> element) {
|
||||
element.at<int, offsetof(struct List, data_)>().set
|
||||
(element.at<int, offsetof(struct List, data_)>().get() + 10);
|
||||
|
||||
Reference in New Issue
Block a user