blob: 45e3fc55898a7c8394339194d47b3e0dc17c4420 [file] [log] [blame]
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +00001/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ART_COMPILER_GC_MAP_BUILDER_H_
18#define ART_COMPILER_GC_MAP_BUILDER_H_
19
20#include <vector>
21
Vladimir Marko80afd022015-05-19 18:08:00 +010022#include "base/bit_utils.h"
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +000023#include "gc_map.h"
24
25namespace art {
26
27class GcMapBuilder {
28 public:
Vladimir Marko80b96d12015-02-19 15:50:28 +000029 template <typename Alloc>
30 GcMapBuilder(std::vector<uint8_t, Alloc>* table, size_t entries, uint32_t max_native_offset,
Vladimir Marko31806a32014-03-20 15:08:57 +000031 size_t references_width)
32 : entries_(entries), references_width_(entries != 0u ? references_width : 0u),
33 native_offset_width_(entries != 0 && max_native_offset != 0
34 ? sizeof(max_native_offset) - CLZ(max_native_offset) / 8u
35 : 0u),
Vladimir Marko80b96d12015-02-19 15:50:28 +000036 in_use_(entries) {
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +000037 // Resize table and set up header.
38 table->resize((EntryWidth() * entries) + sizeof(uint32_t));
Vladimir Marko80b96d12015-02-19 15:50:28 +000039 table_ = table->data();
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +000040 CHECK_LT(native_offset_width_, 1U << 3);
41 (*table)[0] = native_offset_width_ & 7;
42 CHECK_LT(references_width_, 1U << 13);
43 (*table)[0] |= (references_width_ << 3) & 0xFF;
44 (*table)[1] = (references_width_ >> 5) & 0xFF;
45 CHECK_LT(entries, 1U << 16);
46 (*table)[2] = entries & 0xFF;
47 (*table)[3] = (entries >> 8) & 0xFF;
48 }
49
50 void AddEntry(uint32_t native_offset, const uint8_t* references) {
51 size_t table_index = TableIndex(native_offset);
52 while (in_use_[table_index]) {
53 table_index = (table_index + 1) % entries_;
54 }
55 in_use_[table_index] = true;
56 SetCodeOffset(table_index, native_offset);
57 DCHECK_EQ(native_offset, GetCodeOffset(table_index));
58 SetReferences(table_index, references);
59 }
60
61 private:
62 size_t TableIndex(uint32_t native_offset) {
63 return NativePcOffsetToReferenceMap::Hash(native_offset) % entries_;
64 }
65
66 uint32_t GetCodeOffset(size_t table_index) {
67 uint32_t native_offset = 0;
68 size_t table_offset = (table_index * EntryWidth()) + sizeof(uint32_t);
69 for (size_t i = 0; i < native_offset_width_; i++) {
Vladimir Marko80b96d12015-02-19 15:50:28 +000070 native_offset |= table_[table_offset + i] << (i * 8);
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +000071 }
72 return native_offset;
73 }
74
75 void SetCodeOffset(size_t table_index, uint32_t native_offset) {
76 size_t table_offset = (table_index * EntryWidth()) + sizeof(uint32_t);
77 for (size_t i = 0; i < native_offset_width_; i++) {
Vladimir Marko80b96d12015-02-19 15:50:28 +000078 table_[table_offset + i] = (native_offset >> (i * 8)) & 0xFF;
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +000079 }
80 }
81
82 void SetReferences(size_t table_index, const uint8_t* references) {
83 size_t table_offset = (table_index * EntryWidth()) + sizeof(uint32_t);
Vladimir Marko80b96d12015-02-19 15:50:28 +000084 memcpy(&table_[table_offset + native_offset_width_], references, references_width_);
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +000085 }
86
87 size_t EntryWidth() const {
88 return native_offset_width_ + references_width_;
89 }
90
91 // Number of entries in the table.
92 const size_t entries_;
93 // Number of bytes used to encode the reference bitmap.
94 const size_t references_width_;
95 // Number of bytes used to encode a native offset.
Vladimir Marko31806a32014-03-20 15:08:57 +000096 const size_t native_offset_width_;
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +000097 // Entries that are in use.
98 std::vector<bool> in_use_;
99 // The table we're building.
Vladimir Marko80b96d12015-02-19 15:50:28 +0000100 uint8_t* table_;
Nicolas Geoffray92cf83e2014-03-18 17:59:20 +0000101};
102
103} // namespace art
104
105#endif // ART_COMPILER_GC_MAP_BUILDER_H_