From 07bb3c84a2d1eff7f3577cce023dca517aa7c3ed Mon Sep 17 00:00:00 2001
From: Chris Bieneman <beanz@apple.com>
Date: Thu, 2 Jun 2016 22:54:06 +0000
Subject: [obj2yaml] [yaml2obj] Support for MachO nlist and string table

This commit adds round tripping for MachO symbol data. Symbols are entries in the name list, that contain offsets into the string table which is at the end of the __LINKEDIT segment.

llvm-svn: 271604
---
 llvm/tools/yaml2obj/yaml2macho.cpp | 43 +++++++++++++++++++++++++++++++-------
 1 file changed, 36 insertions(+), 7 deletions(-)

(limited to 'llvm/tools/yaml2obj/yaml2macho.cpp')

diff --git a/llvm/tools/yaml2obj/yaml2macho.cpp b/llvm/tools/yaml2obj/yaml2macho.cpp
index b825c9a3494..d65aabc5c86 100644
--- a/llvm/tools/yaml2obj/yaml2macho.cpp
+++ b/llvm/tools/yaml2obj/yaml2macho.cpp
@@ -165,7 +165,7 @@ size_t writeLoadCommandData<MachO::dylinker_command>(MachOYAML::LoadCommand &LC,
 
 template <>
 size_t writeLoadCommandData<MachO::rpath_command>(MachOYAML::LoadCommand &LC,
-                                                     raw_ostream &OS) {
+                                                  raw_ostream &OS) {
   return writePayloadString(LC, OS);
 }
 
@@ -295,23 +295,23 @@ void MachOWriter::writeBindOpcodes(
   }
 }
 
-void MachOWriter::dumpExportEntry(raw_ostream &OS, MachOYAML::ExportEntry &Entry) {
+void MachOWriter::dumpExportEntry(raw_ostream &OS,
+                                  MachOYAML::ExportEntry &Entry) {
   encodeSLEB128(Entry.TerminalSize, OS);
   if (Entry.TerminalSize > 0) {
     encodeSLEB128(Entry.Flags, OS);
-    if ( Entry.Flags & MachO::EXPORT_SYMBOL_FLAGS_REEXPORT ) {
+    if (Entry.Flags & MachO::EXPORT_SYMBOL_FLAGS_REEXPORT) {
       encodeSLEB128(Entry.Other, OS);
       OS << Entry.ImportName;
       OS.write('\0');
-    }
-    else {
+    } else {
       encodeSLEB128(Entry.Address, OS);
       if (Entry.Flags & MachO::EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER)
         encodeSLEB128(Entry.Other, OS);
     }
   }
   OS.write(static_cast<uint8_t>(Entry.Children.size()));
-  for (auto EE : Entry.Children){
+  for (auto EE : Entry.Children) {
     OS << EE.Name;
     OS.write('\0');
     encodeSLEB128(EE.NodeOffset, OS);
@@ -325,6 +325,17 @@ Error MachOWriter::writeExportTrie(raw_ostream &OS) {
   return Error::success();
 }
 
+template <typename NListType>
+void writeNListEntry(MachOYAML::NListEntry &NLE, raw_ostream &OS) {
+  NListType ListEntry;
+  ListEntry.n_strx = NLE.n_strx;
+  ListEntry.n_type = NLE.n_type;
+  ListEntry.n_sect = NLE.n_sect;
+  ListEntry.n_desc = NLE.n_desc;
+  ListEntry.n_value = NLE.n_value;
+  OS.write(reinterpret_cast<const char *>(&ListEntry), sizeof(NListType));
+}
+
 Error MachOWriter::writeLinkEditData(raw_ostream &OS) {
   MachOYAML::LinkEditData &LinkEdit = Obj.LinkEdit;
   MachO::dyld_info_command *DyldInfoOnlyCmd = 0;
@@ -357,9 +368,27 @@ Error MachOWriter::writeLinkEditData(raw_ostream &OS) {
                    LinkEdit.LazyBindOpcodes);
 
   ZeroToOffset(OS, DyldInfoOnlyCmd->export_off);
-  if(auto Err = writeExportTrie(OS))
+  if (auto Err = writeExportTrie(OS))
     return Err;
 
+  ZeroToOffset(OS, SymtabCmd->symoff);
+  
+  for (auto NLE : LinkEdit.NameList) {
+    if (is64Bit)
+      writeNListEntry<MachO::nlist_64>(NLE, OS);
+    else
+      writeNListEntry<MachO::nlist>(NLE, OS);
+  }
+
+  auto currOffset = OS.tell() - fileStart;
+  if (currOffset < SymtabCmd->stroff)
+    Fill(OS, SymtabCmd->stroff - currOffset, 0xDEADBEEFu);
+
+  for (auto Str : LinkEdit.StringTable) {
+    OS.write(Str.data(), Str.size());
+    OS.write('\0');
+  }
+
   // Fill to the end of the string table
   ZeroToOffset(OS, SymtabCmd->stroff + SymtabCmd->strsize);
 
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