commit 9d1020648cc58b36ca0c1aa86f3f7749a00ac84e
author Rafael Espindola <rafael.espindola@gmail.com> Tue Dec 16 01:43:41 2014 +0000
committer Rafael Espindola <rafael.espindola@gmail.com> Tue Dec 16 01:43:41 2014 +0000
tree 6fa7979b58d56ea2b2c2fc3d964fb00db9a0d32b
parent a2162b316679aaf5e00661a5cca8c2dd2deef94f

Start adding thin archive support.

This is just sufficient for 'ar t' to work.

llvm-svn: 224307

llvm/lib/Object/Archive.cpp

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index d169dbe..5aada91 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -22,6 +22,7 @@
 using namespace object;
 
 static const char *const Magic = "!<arch>\n";
+static const char *const ThinMagic = "!<thin>\n";
 
 void Archive::anchor() { }
 
@@ -86,7 +87,10 @@
 
   const ArchiveMemberHeader *Header =
       reinterpret_cast<const ArchiveMemberHeader *>(Start);
-  Data = StringRef(Start, sizeof(ArchiveMemberHeader) + Header->getSize());
+  uint64_t Size = sizeof(ArchiveMemberHeader);
+  if (!Parent->IsThin || Header->getName() == "/" || Header->getName() == "//")
+    Size += Header->getSize();
+  Data = StringRef(Start, Size);
 
   // Setup StartOfFile and PaddingBytes.
   StartOfFile = sizeof(ArchiveMemberHeader);
@@ -100,6 +104,12 @@
   }
 }
 
+uint64_t Archive::Child::getSize() const {
+  if (Parent->IsThin)
+    return getHeader()->getSize();
+  return Data.size() - StartOfFile;
+}
+
 Archive::Child Archive::Child::getNext() const {
   size_t SpaceToSkip = Data.size();
   // If it's odd, add 1 to make it even.
@@ -186,9 +196,13 @@
 
 Archive::Archive(MemoryBufferRef Source, std::error_code &ec)
     : Binary(Binary::ID_Archive, Source), SymbolTable(child_end()) {
+  StringRef Buffer = Data.getBuffer();
   // Check for sufficient magic.
-  if (Data.getBufferSize() < 8 ||
-      StringRef(Data.getBufferStart(), 8) != Magic) {
+  if (Buffer.startswith(ThinMagic)) {
+    IsThin = true;
+  } else if (Buffer.startswith(Magic)) {
+    IsThin = false;
+  } else {
     ec = object_error::invalid_file_type;
     return;
   }