1 //===- XCOFFWriter.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 "llvm/Support/Errc.h"
10 #include "XCOFFWriter.h"
11 
12 namespace llvm {
13 namespace objcopy {
14 namespace xcoff {
15 
16 using namespace object;
17 
18 void XCOFFWriter::finalizeHeaders() {
19   // File header.
20   FileSize += sizeof(XCOFFFileHeader32);
21   // Optional file header.
22   FileSize += Obj.FileHeader.AuxHeaderSize;
23   // Section headers.
24   FileSize += sizeof(XCOFFSectionHeader32) * Obj.Sections.size();
25 }
26 
27 void XCOFFWriter::finalizeSections() {
28   for (const Section &Sec : Obj.Sections) {
29     // Section data.
30     FileSize += Sec.Contents.size();
31     // Relocations.
32     FileSize +=
33         Sec.SectionHeader.NumberOfRelocations * sizeof(XCOFFRelocation32);
34   }
35 }
36 
37 void XCOFFWriter::finalizeSymbolStringTable() {
38   assert(Obj.FileHeader.SymbolTableOffset >= FileSize);
39   FileSize = Obj.FileHeader.SymbolTableOffset;
40   // Symbols and auxiliary entries.
41   FileSize +=
42       Obj.FileHeader.NumberOfSymTableEntries * XCOFF::SymbolTableEntrySize;
43   // String table.
44   FileSize += Obj.StringTable.size();
45 }
46 
47 void XCOFFWriter::finalize() {
48   FileSize = 0;
49   finalizeHeaders();
50   finalizeSections();
51   finalizeSymbolStringTable();
52 }
53 
54 void XCOFFWriter::writeHeaders() {
55   // Write the file header.
56   uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart());
57   memcpy(Ptr, &Obj.FileHeader, sizeof(XCOFFFileHeader32));
58   Ptr += sizeof(XCOFFFileHeader32);
59 
60   // Write the optional header.
61   if (Obj.FileHeader.AuxHeaderSize) {
62     memcpy(Ptr, &Obj.OptionalFileHeader, Obj.FileHeader.AuxHeaderSize);
63     Ptr += Obj.FileHeader.AuxHeaderSize;
64   }
65 
66   // Write section headers.
67   for (const Section &Sec : Obj.Sections) {
68     memcpy(Ptr, &Sec.SectionHeader, sizeof(XCOFFSectionHeader32));
69     Ptr += sizeof(XCOFFSectionHeader32);
70   }
71 }
72 
73 void XCOFFWriter::writeSections() {
74   // Write section data.
75   for (const Section &Sec : Obj.Sections) {
76     uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart()) +
77                    Sec.SectionHeader.FileOffsetToRawData;
78     Ptr = std::copy(Sec.Contents.begin(), Sec.Contents.end(), Ptr);
79   }
80 
81   // Write relocations.
82   for (const Section &Sec : Obj.Sections) {
83     uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart()) +
84                    Sec.SectionHeader.FileOffsetToRelocationInfo;
85     for (const XCOFFRelocation32 &Rel : Sec.Relocations) {
86       memcpy(Ptr, &Rel, sizeof(XCOFFRelocation32));
87       Ptr += sizeof(XCOFFRelocation32);
88     }
89   }
90 }
91 
92 void XCOFFWriter::writeSymbolStringTable() {
93   // Write symbols.
94   uint8_t *Ptr = reinterpret_cast<uint8_t *>(Buf->getBufferStart()) +
95                  Obj.FileHeader.SymbolTableOffset;
96   for (const Symbol &Sym : Obj.Symbols) {
97     memcpy(Ptr, &Sym.Sym, XCOFF::SymbolTableEntrySize);
98     Ptr += XCOFF::SymbolTableEntrySize;
99     // Auxiliary symbols.
100     memcpy(Ptr, Sym.AuxSymbolEntries.data(), Sym.AuxSymbolEntries.size());
101     Ptr += Sym.AuxSymbolEntries.size();
102   }
103   // Write the string table.
104   memcpy(Ptr, Obj.StringTable.data(), Obj.StringTable.size());
105   Ptr += Obj.StringTable.size();
106 }
107 
108 Error XCOFFWriter::write() {
109   finalize();
110   Buf = WritableMemoryBuffer::getNewMemBuffer(FileSize);
111   if (!Buf)
112     return createStringError(errc::not_enough_memory,
113                              "failed to allocate memory buffer of " +
114                                  Twine::utohexstr(FileSize) + " bytes");
115 
116   writeHeaders();
117   writeSections();
118   writeSymbolStringTable();
119   Out.write(Buf->getBufferStart(), Buf->getBufferSize());
120   return Error::success();
121 }
122 
123 } // end namespace xcoff
124 } // end namespace objcopy
125 } // end namespace llvm
126