From 4b83cb5390c7c66a74bc39a9ec85d804695b14c3 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Tue, 14 Jul 2015 22:18:43 +0000
Subject: Add support for reading members out of thin archives.

For now the Archive owns the buffers of the thin archive members.
This makes for a simple API, but all the buffers are destructed
only when the archive is destructed. This should be fine since we
close the files after mmap so we should not hit an open file
limit.

llvm-svn: 242215
---
 llvm/lib/Object/Archive.cpp | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

(limited to 'llvm/lib/Object')

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index c29e63941f2..d4821196a6c 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
 
 using namespace llvm;
 using namespace object;
@@ -115,6 +116,23 @@ uint64_t Archive::Child::getRawSize() const {
   return getHeader()->getSize();
 }
 
+ErrorOr<StringRef> Archive::Child::getBuffer() const {
+  if (!Parent->IsThin)
+    return StringRef(Data.data() + StartOfFile, getSize());
+  ErrorOr<StringRef> Name = getName();
+  if (std::error_code EC = Name.getError())
+    return EC;
+  SmallString<128> FullName =
+      Parent->getMemoryBufferRef().getBufferIdentifier();
+  sys::path::remove_filename(FullName);
+  sys::path::append(FullName, *Name);
+  ErrorOr<std::unique_ptr<MemoryBuffer>> Buf = MemoryBuffer::getFile(FullName);
+  if (std::error_code EC = Buf.getError())
+    return EC;
+  Parent->ThinBuffers.push_back(std::move(*Buf));
+  return Parent->ThinBuffers.back()->getBuffer();
+}
+
 Archive::Child Archive::Child::getNext() const {
   size_t SpaceToSkip = Data.size();
   // If it's odd, add 1 to make it even.
@@ -186,7 +204,10 @@ ErrorOr<MemoryBufferRef> Archive::Child::getMemoryBufferRef() const {
   if (std::error_code EC = NameOrErr.getError())
     return EC;
   StringRef Name = NameOrErr.get();
-  return MemoryBufferRef(getBuffer(), Name);
+  ErrorOr<StringRef> Buf = getBuffer();
+  if (std::error_code EC = Buf.getError())
+    return EC;
+  return MemoryBufferRef(*Buf, Name);
 }
 
 ErrorOr<std::unique_ptr<Binary>>
-- 
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