src/hotspot/share/gc/shared/c2/barrierSetC2.hpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */

 #ifndef SHARE_GC_SHARED_C2_BARRIERSETC2_HPP
 #define SHARE_GC_SHARED_C2_BARRIERSETC2_HPP

 #include "memory/allocation.hpp"
 #include "oops/accessDecorators.hpp"
 #include "opto/loopnode.hpp"
 #include "opto/memnode.hpp"
 #include "utilities/globalDefinitions.hpp"

 // This means the access is mismatched. This means the value of an access
 // is not equivalent to the value pointed to by the address.
 const DecoratorSet C2_MISMATCHED             = DECORATOR_LAST << 1;
 // The access may not be aligned to its natural size.
 const DecoratorSet C2_UNALIGNED              = DECORATOR_LAST << 2;
 // The atomic cmpxchg is weak, meaning that spurious false negatives are allowed,
 // but never false positives.
 const DecoratorSet C2_WEAK_CMPXCHG           = DECORATOR_LAST << 3;
 // This denotes that a load has control dependency.
 const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4;
 // This denotes that a load that must be pinned.
 const DecoratorSet C2_PINNED_LOAD            = DECORATOR_LAST << 5;
 // This denotes that the access is produced from the sun.misc.Unsafe intrinsics.
 const DecoratorSet C2_UNSAFE_ACCESS          = DECORATOR_LAST << 6;
 // This denotes that the access mutates state.
 const DecoratorSet C2_WRITE_ACCESS           = DECORATOR_LAST << 7;
 // This denotes that the access reads state.
 const DecoratorSet C2_READ_ACCESS            = DECORATOR_LAST << 8;

 class GraphKit;
 class IdealKit;
 class Node;
 class Type;
 class TypePtr;
 class PhaseMacroExpand;

 // This class wraps a node and a type.
 class C2AccessValue: public StackObj {
 protected:
   Node* _node;
   const Type* _type;

 public:
   C2AccessValue(Node* node, const Type* type) :
     _node(node),
     _type(type) {}

   Node* node() const        { return _node; }
   const Type* type() const  { return _type; }

   void set_node(Node* node) { _node = node; }
 };

 // This class wraps a node and a pointer type.
 class C2AccessValuePtr: public C2AccessValue {
   int _alias_idx;

 public:
   C2AccessValuePtr(Node* node, const TypePtr* type) :
     C2AccessValue(node, reinterpret_cast<const Type*>(type)) {}

   const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); }
   int alias_idx() const       { return _alias_idx; }
 };

 // This class wraps a bunch of context parameters thare are passed around in the
 // BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
 class C2Access: public StackObj {
 protected:
   GraphKit*         _kit;
   DecoratorSet      _decorators;
   BasicType         _type;
   Node*             _base;
   C2AccessValuePtr& _addr;
   Node*             _raw_access;

   void fixup_decorators();
   void* barrier_set_state() const;

 public:
   C2Access(GraphKit* kit, DecoratorSet decorators,
            BasicType type, Node* base, C2AccessValuePtr& addr) :
     _kit(kit),
     _decorators(decorators),
     _type(type),
     _base(base),
     _addr(addr),
     _raw_access(NULL)
   {
     fixup_decorators();
   }

   GraphKit* kit() const           { return _kit; }
   DecoratorSet decorators() const { return _decorators; }
   Node* base() const              { return _base; }
   C2AccessValuePtr& addr() const  { return _addr; }
   BasicType type() const          { return _type; }
   bool is_oop() const             { return _type == T_OBJECT || _type == T_ARRAY; }
   bool is_raw() const             { return (_decorators & AS_RAW) != 0; }
   Node* raw_access() const        { return _raw_access; }

   void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
   virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.

   MemNode::MemOrd mem_node_mo() const;
   bool needs_cpu_membar() const;

   template <typename T>
   T barrier_set_state_as() const {
     return reinterpret_cast<T>(barrier_set_state());
   }
 };

 // This class wraps a bunch of context parameters thare are passed around in the
 // BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
 class C2AtomicAccess: public C2Access {
   Node* _memory;
   uint  _alias_idx;
   bool  _needs_pinning;

 public:
   C2AtomicAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
                  Node* base, C2AccessValuePtr& addr, uint alias_idx) :
     C2Access(kit, decorators, type, base, addr),
     _memory(NULL),
     _alias_idx(alias_idx),
     _needs_pinning(true) {}

   // Set the memory node based on the current memory slice.
   virtual void set_memory();

   Node* memory() const       { return _memory; }
   uint alias_idx() const     { return _alias_idx; }
   bool needs_pinning() const { return _needs_pinning; }

   void set_needs_pinning(bool value)    { _needs_pinning = value; }
 };

 // This is the top-level class for the backend of the Access API in C2.
 // The top-level class is responsible for performing raw accesses. The
 // various GC barrier sets inherit from the BarrierSetC2 class to sprinkle
 // barriers into the accesses.
 class BarrierSetC2: public CHeapObj<mtGC> {
 protected:
   virtual void resolve_address(C2Access& access) const;
   virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
   virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;

   virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val,
                                                Node* new_val, const Type* val_type) const;
   virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val,
                                                 Node* new_val, const Type* value_type) const;
   virtual Node* atomic_xchg_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const;
   virtual Node* atomic_add_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const;

 public:
   // This is the entry-point for the backend to perform accesses through the Access API.
   virtual Node* store_at(C2Access& access, C2AccessValue& val) const;
   virtual Node* load_at(C2Access& access, const Type* val_type) const;

   virtual Node* atomic_cmpxchg_val_at(C2AtomicAccess& access, Node* expected_val,
                                       Node* new_val, const Type* val_type) const;
   virtual Node* atomic_cmpxchg_bool_at(C2AtomicAccess& access, Node* expected_val,
                                        Node* new_val, const Type* val_type) const;
   virtual Node* atomic_xchg_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const;
   virtual Node* atomic_add_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const;

   virtual void clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const;

   virtual Node* ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const { return NULL; }
   virtual Node* identity_node(PhaseGVN* phase, Node* n) const { return n; }

   // These are general helper methods used by C2
   virtual bool array_copy_requires_gc_barriers(BasicType type) const { return false; }
   virtual void clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const;

   // Support for GC barriers emitted during parsing
   virtual bool has_load_barriers() const { return false; }
   virtual bool is_gc_barrier_node(Node* node) const { return false; }
   virtual Node* step_over_gc_barrier(Node* c) const { return c; }

   // Support for macro expanded GC barriers
   virtual void register_potential_barrier_node(Node* node) const { }
   virtual void unregister_potential_barrier_node(Node* node) const { }
   virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { }
   virtual void enqueue_useful_gc_barrier(Unique_Node_List &worklist, Node* node) const {}
   virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful) const {}
   virtual void add_users_to_worklist(Unique_Node_List* worklist) const {}

   // Allow barrier sets to have shared state that is preserved across a compilation unit.
   // This could for example comprise macro nodes to be expanded during macro expansion.
   virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; }
   // If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
   // expanded later, then now is the time to do so.
   virtual bool expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
   virtual void verify_gc_barriers(bool post_parse) const {}
 };

 #endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP
	/*
	* Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*
	*/

	#ifndef SHARE_GC_SHARED_C2_BARRIERSETC2_HPP
	#define SHARE_GC_SHARED_C2_BARRIERSETC2_HPP

	#include "memory/allocation.hpp"
	#include "oops/accessDecorators.hpp"
	#include "opto/loopnode.hpp"
	#include "opto/memnode.hpp"
	#include "utilities/globalDefinitions.hpp"

	// This means the access is mismatched. This means the value of an access
	// is not equivalent to the value pointed to by the address.
	const DecoratorSet C2_MISMATCHED = DECORATOR_LAST << 1;
	// The access may not be aligned to its natural size.
	const DecoratorSet C2_UNALIGNED = DECORATOR_LAST << 2;
	// The atomic cmpxchg is weak, meaning that spurious false negatives are allowed,
	// but never false positives.
	const DecoratorSet C2_WEAK_CMPXCHG = DECORATOR_LAST << 3;
	// This denotes that a load has control dependency.
	const DecoratorSet C2_CONTROL_DEPENDENT_LOAD = DECORATOR_LAST << 4;
	// This denotes that a load that must be pinned.
	const DecoratorSet C2_PINNED_LOAD = DECORATOR_LAST << 5;
	// This denotes that the access is produced from the sun.misc.Unsafe intrinsics.
	const DecoratorSet C2_UNSAFE_ACCESS = DECORATOR_LAST << 6;
	// This denotes that the access mutates state.
	const DecoratorSet C2_WRITE_ACCESS = DECORATOR_LAST << 7;
	// This denotes that the access reads state.
	const DecoratorSet C2_READ_ACCESS = DECORATOR_LAST << 8;

	class GraphKit;
	class IdealKit;
	class Node;
	class Type;
	class TypePtr;
	class PhaseMacroExpand;

	// This class wraps a node and a type.
	class C2AccessValue: public StackObj {
	protected:
	Node* _node;
	const Type* _type;

	public:
	C2AccessValue(Node* node, const Type* type) :
	_node(node),
	_type(type) {}

	Node* node() const { return _node; }
	const Type* type() const { return _type; }

	void set_node(Node* node) { _node = node; }
	};

	// This class wraps a node and a pointer type.
	class C2AccessValuePtr: public C2AccessValue {
	int _alias_idx;

	public:
	C2AccessValuePtr(Node* node, const TypePtr* type) :
	C2AccessValue(node, reinterpret_cast<const Type*>(type)) {}

	const TypePtr* type() const { return reinterpret_cast<const TypePtr*>(_type); }
	int alias_idx() const { return _alias_idx; }
	};

	// This class wraps a bunch of context parameters thare are passed around in the
	// BarrierSetC2 backend hierarchy, for loads and stores, to reduce boiler plate.
	class C2Access: public StackObj {
	protected:
	GraphKit* _kit;
	DecoratorSet _decorators;
	BasicType _type;
	Node* _base;
	C2AccessValuePtr& _addr;
	Node* _raw_access;

	void fixup_decorators();
	void* barrier_set_state() const;

	public:
	C2Access(GraphKit* kit, DecoratorSet decorators,
	BasicType type, Node* base, C2AccessValuePtr& addr) :
	_kit(kit),
	_decorators(decorators),
	_type(type),
	_base(base),
	_addr(addr),
	_raw_access(NULL)
	{
	fixup_decorators();
	}

	GraphKit* kit() const { return _kit; }
	DecoratorSet decorators() const { return _decorators; }
	Node* base() const { return _base; }
	C2AccessValuePtr& addr() const { return _addr; }
	BasicType type() const { return _type; }
	bool is_oop() const { return _type == T_OBJECT \|\| _type == T_ARRAY; }
	bool is_raw() const { return (_decorators & AS_RAW) != 0; }
	Node* raw_access() const { return _raw_access; }

	void set_raw_access(Node* raw_access) { _raw_access = raw_access; }
	virtual void set_memory() {} // no-op for normal accesses, but not for atomic accesses.

	MemNode::MemOrd mem_node_mo() const;
	bool needs_cpu_membar() const;

	template <typename T>
	T barrier_set_state_as() const {
	return reinterpret_cast<T>(barrier_set_state());
	}
	};

	// This class wraps a bunch of context parameters thare are passed around in the
	// BarrierSetC2 backend hierarchy, for atomic accesses, to reduce boiler plate.
	class C2AtomicAccess: public C2Access {
	Node* _memory;
	uint _alias_idx;
	bool _needs_pinning;

	public:
	C2AtomicAccess(GraphKit* kit, DecoratorSet decorators, BasicType type,
	Node* base, C2AccessValuePtr& addr, uint alias_idx) :
	C2Access(kit, decorators, type, base, addr),
	_memory(NULL),
	_alias_idx(alias_idx),
	_needs_pinning(true) {}

	// Set the memory node based on the current memory slice.
	virtual void set_memory();

	Node* memory() const { return _memory; }
	uint alias_idx() const { return _alias_idx; }
	bool needs_pinning() const { return _needs_pinning; }

	void set_needs_pinning(bool value) { _needs_pinning = value; }
	};

	// This is the top-level class for the backend of the Access API in C2.
	// The top-level class is responsible for performing raw accesses. The
	// various GC barrier sets inherit from the BarrierSetC2 class to sprinkle
	// barriers into the accesses.
	class BarrierSetC2: public CHeapObj<mtGC> {
	protected:
	virtual void resolve_address(C2Access& access) const;
	virtual Node* store_at_resolved(C2Access& access, C2AccessValue& val) const;
	virtual Node* load_at_resolved(C2Access& access, const Type* val_type) const;

	virtual Node* atomic_cmpxchg_val_at_resolved(C2AtomicAccess& access, Node* expected_val,
	Node* new_val, const Type* val_type) const;
	virtual Node* atomic_cmpxchg_bool_at_resolved(C2AtomicAccess& access, Node* expected_val,
	Node* new_val, const Type* value_type) const;
	virtual Node* atomic_xchg_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const;
	virtual Node* atomic_add_at_resolved(C2AtomicAccess& access, Node* new_val, const Type* val_type) const;

	public:
	// This is the entry-point for the backend to perform accesses through the Access API.
	virtual Node* store_at(C2Access& access, C2AccessValue& val) const;
	virtual Node* load_at(C2Access& access, const Type* val_type) const;

	virtual Node* atomic_cmpxchg_val_at(C2AtomicAccess& access, Node* expected_val,
	Node* new_val, const Type* val_type) const;
	virtual Node* atomic_cmpxchg_bool_at(C2AtomicAccess& access, Node* expected_val,
	Node* new_val, const Type* val_type) const;
	virtual Node* atomic_xchg_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const;
	virtual Node* atomic_add_at(C2AtomicAccess& access, Node* new_val, const Type* value_type) const;

	virtual void clone(GraphKit* kit, Node* src, Node* dst, Node* size, bool is_array) const;

	virtual Node* ideal_node(PhaseGVN* phase, Node* n, bool can_reshape) const { return NULL; }
	virtual Node* identity_node(PhaseGVN* phase, Node* n) const { return n; }

	// These are general helper methods used by C2
	virtual bool array_copy_requires_gc_barriers(BasicType type) const { return false; }
	virtual void clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const;

	// Support for GC barriers emitted during parsing
	virtual bool has_load_barriers() const { return false; }
	virtual bool is_gc_barrier_node(Node* node) const { return false; }
	virtual Node* step_over_gc_barrier(Node* c) const { return c; }

	// Support for macro expanded GC barriers
	virtual void register_potential_barrier_node(Node* node) const { }
	virtual void unregister_potential_barrier_node(Node* node) const { }
	virtual void eliminate_gc_barrier(PhaseMacroExpand* macro, Node* node) const { }
	virtual void enqueue_useful_gc_barrier(Unique_Node_List &worklist, Node* node) const {}
	virtual void eliminate_useless_gc_barriers(Unique_Node_List &useful) const {}
	virtual void add_users_to_worklist(Unique_Node_List* worklist) const {}

	// Allow barrier sets to have shared state that is preserved across a compilation unit.
	// This could for example comprise macro nodes to be expanded during macro expansion.
	virtual void* create_barrier_state(Arena* comp_arena) const { return NULL; }
	// If the BarrierSetC2 state has kept macro nodes in its compilation unit state to be
	// expanded later, then now is the time to do so.
	virtual bool expand_macro_nodes(PhaseMacroExpand* macro) const { return false; }
	virtual void verify_gc_barriers(bool post_parse) const {}
	};

	#endif // SHARE_GC_SHARED_C2_BARRIERSETC2_HPP