1 /*
2 * Copyright 2011, 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 ELF_SECTION_PROGBITS_HXX
18 #define ELF_SECTION_PROGBITS_HXX
19
20 #include "ELFTypes.h"
21 #include "StubLayout.h"
22
23 #include <llvm/Support/Format.h>
24 #include <llvm/Support/raw_ostream.h>
25
26 #include "utils/raw_ostream.h"
27
28 #include <string.h>
29
30 template <unsigned Bitwidth>
31 template <typename Archiver>
32 ELFSectionProgBits<Bitwidth> *
read(Archiver & AR,ELFObjectTy * owner,ELFSectionHeaderTy const * sh)33 ELFSectionProgBits<Bitwidth>::read(Archiver &AR,
34 ELFObjectTy *owner,
35 ELFSectionHeaderTy const *sh) {
36 int machine = owner->getHeader()->getMachine();
37 ELFSectionProgBits *secp = new ELFSectionProgBits(machine);
38 std::unique_ptr<ELFSectionProgBits> result(secp);
39 size_t max_num_stubs = 0;
40 // Align section boundary to 4 bytes.
41 size_t section_size = (sh->getSize() + 3) / 4 * 4;
42 size_t alloc_size = section_size;
43 StubLayout *stubs = result->getStubLayout();
44 if (stubs) {
45 // Compute the maximal possible numbers of stubs
46 max_num_stubs = 0;
47 for (const char* prefix : {".rel", ".rela"}) {
48 std::string reltab_name(prefix + std::string(sh->getName()));
49
50 ELFSectionRelTableTy const *reltab =
51 static_cast<ELFSectionRelTableTy *>(
52 owner->getSectionByName(reltab_name.c_str()));
53
54 if (reltab) {
55 // If we have relocation table, then get the approximation of
56 // maximum numbers of stubs.
57 max_num_stubs += reltab->getMaxNumStubs(owner);
58 }
59 }
60
61 // Compute the stub table size
62 size_t stub_table_size = stubs->calcStubTableSize(max_num_stubs);
63
64 // Allocate PROGBITS section with stubs table
65 alloc_size += stub_table_size;
66 }
67
68 // Allocate text section
69 if (!result->chunk.allocate(alloc_size)) {
70 return NULL;
71 }
72
73 if (stubs) {
74 stubs->initStubTable(result->chunk.getBuffer() + section_size,
75 max_num_stubs);
76 }
77
78 result->sh = sh;
79
80 if (!result->serialize(AR)) {
81 // Unable to read the progbits section.
82 return NULL;
83 }
84
85 return result.release();
86 }
87
88 #endif // ELF_SECTION_PROGBITS_HXX
89