llvm-ar: Pad the symbol table to 4 bytes.

It looks like ld64 requires it. With this we seem to be able to bootstrap using
llvm-ar+/usr/bin/true instead of ar+ranlib (currently on stage2).

llvm-svn: 241842

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/Object/ArchiveWriter.cpp b/llvm/lib/Object/ArchiveWriter.cpp
index c485b34a081..1148c847549 100644
--- a/llvm/lib/Object/ArchiveWriter.cpp
+++ b/llvm/lib/Object/ArchiveWriter.cpp
@@ -237,8 +237,11 @@ writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
     print32(Out, Kind, StringTable.size()); // byte count of the string table
   Out << StringTable;
 
-  if (Out.tell() % 2)
-    Out << '\0';
+  // ld64 requires the next member header to start at an offset that is
+  // 4 bytes aligned.
+  unsigned Pad = OffsetToAlignment(Out.tell(), 4);
+  while (Pad--)
+    Out.write(uint8_t(0));
 
   // Patch up the size of the symbol table now that we know how big it is.
   unsigned Pos = Out.tell();