1 //===- bolt/Rewrite/ExecutableFileMemoryManager.cpp -----------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "bolt/Rewrite/ExecutableFileMemoryManager.h"
10 #include "bolt/Rewrite/RewriteInstance.h"
11 
12 #undef  DEBUG_TYPE
13 #define DEBUG_TYPE "efmm"
14 
15 using namespace llvm;
16 using namespace object;
17 using namespace bolt;
18 
19 namespace llvm {
20 
21 namespace bolt {
22 
23 uint8_t *ExecutableFileMemoryManager::allocateSection(intptr_t Size,
24                                                       unsigned Alignment,
25                                                       unsigned SectionID,
26                                                       StringRef SectionName,
27                                                       bool IsCode,
28                                                       bool IsReadOnly) {
29   // Register a debug section as a note section.
30   if (!ObjectsLoaded && RewriteInstance::isDebugSection(SectionName)) {
31     uint8_t *DataCopy = new uint8_t[Size];
32     BinarySection &Section =
33         BC.registerOrUpdateNoteSection(SectionName, DataCopy, Size, Alignment);
34     Section.setSectionID(SectionID);
35     assert(!Section.isAllocatable() && "note sections cannot be allocatable");
36     return DataCopy;
37   }
38 
39   if (!IsCode && (SectionName == ".strtab" || SectionName == ".symtab" ||
40                   SectionName == "" || SectionName.startswith(".rela.")))
41     return SectionMemoryManager::allocateDataSection(Size, Alignment, SectionID,
42                                                      SectionName, IsReadOnly);
43 
44   uint8_t *Ret;
45   if (IsCode)
46     Ret = SectionMemoryManager::allocateCodeSection(Size, Alignment, SectionID,
47                                                     SectionName);
48   else
49     Ret = SectionMemoryManager::allocateDataSection(Size, Alignment, SectionID,
50                                                     SectionName, IsReadOnly);
51 
52   SmallVector<char, 256> Buf;
53   if (ObjectsLoaded > 0) {
54     if (BC.isELF()) {
55       SectionName = (Twine(SectionName) + ".bolt.extra." + Twine(ObjectsLoaded))
56                         .toStringRef(Buf);
57     } else if (BC.isMachO()) {
58       assert((SectionName == "__text" || SectionName == "__data" ||
59               SectionName == "__fini" || SectionName == "__setup" ||
60               SectionName == "__cstring" || SectionName == "__literal16") &&
61              "Unexpected section in the instrumentation library");
62       // Sections coming from the instrumentation runtime are prefixed with "I".
63       SectionName = ("I" + Twine(SectionName)).toStringRef(Buf);
64     }
65   }
66 
67   BinarySection &Section = BC.registerOrUpdateSection(
68       SectionName, ELF::SHT_PROGBITS,
69       BinarySection::getFlags(IsReadOnly, IsCode, true), Ret, Size, Alignment);
70   Section.setSectionID(SectionID);
71   assert(Section.isAllocatable() &&
72          "verify that allocatable is marked as allocatable");
73 
74   LLVM_DEBUG(
75       dbgs() << "BOLT: allocating "
76              << (IsCode ? "code" : (IsReadOnly ? "read-only data" : "data"))
77              << " section : " << SectionName << " with size " << Size
78              << ", alignment " << Alignment << " at 0x" << Ret
79              << ", ID = " << SectionID << "\n");
80   return Ret;
81 }
82 
83 bool ExecutableFileMemoryManager::finalizeMemory(std::string *ErrMsg) {
84   LLVM_DEBUG(dbgs() << "BOLT: finalizeMemory()\n");
85   ++ObjectsLoaded;
86   return SectionMemoryManager::finalizeMemory(ErrMsg);
87 }
88 
89 ExecutableFileMemoryManager::~ExecutableFileMemoryManager() {}
90 
91 } // namespace bolt
92 
93 } // namespace llvm
94