ELFSectionProgBits.hxx revision e8d2d07e1f060d434a475944e714bf8e00caf754 
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
30template <unsigned Bitwidth>
31template <typename Archiver>
32ELFSectionProgBits<Bitwidth> *
33ELFSectionProgBits<Bitwidth>::read(Archiver &AR,
34                                   ELFObjectTy *owner,
35                                   ELFSectionHeaderTy const *sh) {
36  int machine = owner->getHeader()->getMachine();
37  ELFSectionProgBits *secp = new ELFSectionProgBits(machine);
38  llvm::OwningPtr<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    std::string reltab_name(".rel" + std::string(sh->getName()));
47
48    ELFSectionRelTableTy const *reltab =
49      static_cast<ELFSectionRelTableTy *>(
50        owner->getSectionByName(reltab_name.c_str()));
51
52    if (reltab) {
53      // If we have relocation table, then get the approximation of
54      // maximum numbers of stubs.
55      max_num_stubs = reltab->getMaxNumStubs(owner);
56    }
57
58    // Compute the stub table size
59    size_t stub_table_size = stubs->calcStubTableSize(max_num_stubs);
60
61    // Allocate PROGBITS section with stubs table
62    alloc_size += stub_table_size;
63  }
64
65  // Allocate text section
66  if (!result->chunk.allocate(alloc_size)) {
67    return NULL;
68  }
69
70  if (stubs) {
71    stubs->initStubTable(result->chunk.getBuffer() + section_size,
72                         max_num_stubs);
73  }
74
75  result->sh = sh;
76
77  if (!result->serialize(AR)) {
78    // Unable to read the progbits section.
79    return NULL;
80  }
81
82  return result.take();
83}
84
85#endif // ELF_SECTION_PROGBITS_HXX
86