76 FreeBlock* link() const { return _link; }
77 void set_link(FreeBlock* link) { _link = link; }
78 };
79
80 class CodeHeap : public CHeapObj<mtCode> {
81 friend class VMStructs;
82 private:
83 VirtualSpace _memory; // the memory holding the blocks
84 VirtualSpace _segmap; // the memory holding the segment map
85
86 size_t _number_of_committed_segments;
87 size_t _number_of_reserved_segments;
88 size_t _segment_size;
89 int _log2_segment_size;
90
91 size_t _next_segment;
92
93 FreeBlock* _freelist;
94 size_t _freelist_segments; // No. of segments in freelist
95
96 // Helper functions
97 size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
98 size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
99
100 size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; }
101 HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
102
103 void mark_segmap_as_free(size_t beg, size_t end);
104 void mark_segmap_as_used(size_t beg, size_t end);
105
106 // Freelist management helpers
107 FreeBlock* following_block(FreeBlock *b);
108 void insert_after(FreeBlock* a, FreeBlock* b);
109 void merge_right (FreeBlock* a);
110
111 // Toplevel freelist management
112 void add_to_freelist(HeapBlock *b);
113 FreeBlock* search_freelist(size_t length, bool is_critical);
114
115 // Iteration helpers
116 void* next_free(HeapBlock* b) const;
117 HeapBlock* first_block() const;
118 HeapBlock* next_block(HeapBlock* b) const;
119 HeapBlock* block_start(void* p) const;
120
121 // to perform additional actions on creation of executable code
122 void on_code_mapping(char* base, size_t size);
123
124 public:
125 CodeHeap();
126
127 // Heap extents
128 bool reserve(size_t reserved_size, size_t committed_size, size_t segment_size);
129 void release(); // releases all allocated memory
130 bool expand_by(size_t size); // expands commited memory by size
131 void shrink_by(size_t size); // shrinks commited memory by size
132 void clear(); // clears all heap contents
133
134 // Memory allocation
135 void* allocate (size_t size, bool is_critical); // allocates a block of size or returns NULL
136 void deallocate(void* p); // deallocates a block
137
138 // Attributes
139 char* low_boundary() const { return _memory.low_boundary (); }
140 char* high() const { return _memory.high(); }
141 char* high_boundary() const { return _memory.high_boundary(); }
142
143 bool contains(const void* p) const { return low_boundary() <= p && p < high(); }
144 void* find_start(void* p) const; // returns the block containing p or NULL
145 size_t alignment_unit() const; // alignment of any block
146 size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit
147 static size_t header_size(); // returns the header size for each heap block
148
149 // Iteration
150
151 // returns the first block or NULL
152 void* first() const { return next_free(first_block()); }
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76 FreeBlock* link() const { return _link; }
77 void set_link(FreeBlock* link) { _link = link; }
78 };
79
80 class CodeHeap : public CHeapObj<mtCode> {
81 friend class VMStructs;
82 private:
83 VirtualSpace _memory; // the memory holding the blocks
84 VirtualSpace _segmap; // the memory holding the segment map
85
86 size_t _number_of_committed_segments;
87 size_t _number_of_reserved_segments;
88 size_t _segment_size;
89 int _log2_segment_size;
90
91 size_t _next_segment;
92
93 FreeBlock* _freelist;
94 size_t _freelist_segments; // No. of segments in freelist
95
96 enum { free_sentinel = 0xFF };
97
98 // Helper functions
99 size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
100 size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
101
102 size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; }
103 bool is_segment_unused(int val) const { return val == free_sentinel; }
104 HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
105
106 void mark_segmap_as_free(size_t beg, size_t end);
107 void mark_segmap_as_used(size_t beg, size_t end);
108
109 // Freelist management helpers
110 FreeBlock* following_block(FreeBlock* b);
111 void insert_after(FreeBlock* a, FreeBlock* b);
112 bool merge_right (FreeBlock* a);
113
114 // Toplevel freelist management
115 void add_to_freelist(HeapBlock* b);
116 FreeBlock* search_freelist(size_t length, bool is_critical);
117
118 // Iteration helpers
119 void* next_free(HeapBlock* b) const;
120 HeapBlock* first_block() const;
121 HeapBlock* next_block(HeapBlock* b) const;
122 HeapBlock* block_start(void* p) const;
123
124 // to perform additional actions on creation of executable code
125 void on_code_mapping(char* base, size_t size);
126 void clear(); // clears all heap contents
127
128
129 public:
130 CodeHeap();
131
132 // Heap extents
133 bool reserve(size_t reserved_size, size_t committed_size, size_t segment_size);
134 bool expand_by(size_t size); // expands committed memory by size
135
136 // Memory allocation
137 void* allocate (size_t size, bool is_critical); // allocates a block of size or returns NULL
138 void deallocate(void* p); // deallocates a block
139
140 // Attributes
141 char* low_boundary() const { return _memory.low_boundary (); }
142 char* high() const { return _memory.high(); }
143 char* high_boundary() const { return _memory.high_boundary(); }
144
145 bool contains(const void* p) const { return low_boundary() <= p && p < high(); }
146 void* find_start(void* p) const; // returns the block containing p or NULL
147 size_t alignment_unit() const; // alignment of any block
148 size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit
149 static size_t header_size(); // returns the header size for each heap block
150
151 // Iteration
152
153 // returns the first block or NULL
154 void* first() const { return next_free(first_block()); }
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