From aaf98ead114bcd51cd2479badfe28b8d0e4895c2 Mon Sep 17 00:00:00 2001
From: "Michael J. Spencer" <bigcheesegs@gmail.com>
Date: Tue, 25 Oct 2011 22:30:42 +0000
Subject: [PATCH] Object/Archive: Add BSD style long file name support and skip
 internal members.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142981 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Object/Archive.h |  2 +-
 lib/Object/Archive.cpp        | 55 ++++++++++++++++++++++++++++++-----
 2 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/include/llvm/Object/Archive.h b/include/llvm/Object/Archive.h
index 4f081206c5b..d72037020ae 100644
--- a/include/llvm/Object/Archive.h
+++ b/include/llvm/Object/Archive.h
@@ -71,7 +71,7 @@ public:
 
   Archive(MemoryBuffer *source, error_code &ec);
 
-  child_iterator begin_children() const;
+  child_iterator begin_children(bool skip_internal = true) const;
   child_iterator end_children() const;
 
   // Cast methods.
diff --git a/lib/Object/Archive.cpp b/lib/Object/Archive.cpp
index e2eaff53c1f..348b7536e80 100644
--- a/lib/Object/Archive.cpp
+++ b/lib/Object/Archive.cpp
@@ -32,7 +32,11 @@ struct ArchiveMemberHeader {
 
   ///! Get the name without looking up long names.
   StringRef getName() const {
-    char EndCond = Name[0] == '/' ? ' ' : '/';
+    char EndCond;
+    if (Name[0] == '/' || Name[0] == '#')
+      EndCond = ' ';
+    else
+      EndCond = '/';
     StringRef::size_type end = StringRef(Name, sizeof(Name)).find(EndCond);
     if (end == StringRef::npos)
       end = sizeof(Name);
@@ -53,6 +57,21 @@ const ArchiveMemberHeader *ToHeader(const char *base) {
 }
 }
 
+static bool isInternalMember(const ArchiveMemberHeader &amh) {
+  const char *internals[] = {
+    "/",
+    "//",
+    "#_LLVM_SYM_TAB_#"
+    };
+
+  StringRef name = amh.getName();
+  for (std::size_t i = 0; i < sizeof(internals) / sizeof(*internals); ++i) {
+    if (name == internals[i])
+      return true;
+  }
+  return false;
+}
+
 Archive::Child Archive::Child::getNext() const {
   size_t SpaceToSkip = sizeof(ArchiveMemberHeader) +
     ToHeader(Data.data())->getSize();
@@ -101,6 +120,11 @@ error_code Archive::Child::getName(StringRef &Result) const {
       return object_error::parse_failed;
     Result = addr;
     return object_error::success;
+  } else if (name.startswith("#1/")) {
+    APInt name_size;
+    name.substr(3).getAsInteger(10, name_size);
+    Result = Data.substr(0, name_size.getZExtValue());
+    return object_error::success;
   }
   // It's a simple name.
   if (name[name.size() - 1] == '/')
@@ -111,14 +135,27 @@ error_code Archive::Child::getName(StringRef &Result) const {
 }
 
 uint64_t Archive::Child::getSize() const {
-  return ToHeader(Data.data())->getSize();
+  uint64_t size = ToHeader(Data.data())->getSize();
+  // Don't include attached name.
+  StringRef name =  ToHeader(Data.data())->getName();
+  if (name.startswith("#1/")) {
+    APInt name_size;
+    name.substr(3).getAsInteger(10, name_size);
+    size -= name_size.getZExtValue();
+  }
+  return size;
 }
 
 MemoryBuffer *Archive::Child::getBuffer() const {
   StringRef name;
   if (getName(name)) return NULL;
-  return MemoryBuffer::getMemBuffer(Data.substr(sizeof(ArchiveMemberHeader),
-                                                getSize()),
+  int size = sizeof(ArchiveMemberHeader);
+  if (name.startswith("#1/")) {
+    APInt name_size;
+    name.substr(3).getAsInteger(10, name_size);
+    size += name_size.getZExtValue();
+  }
+  return MemoryBuffer::getMemBuffer(Data.substr(size, getSize()),
                                     name,
                                     false);
 }
@@ -144,7 +181,7 @@ Archive::Archive(MemoryBuffer *source, error_code &ec)
   }
 
   // Get the string table. It's the 3rd member.
-  child_iterator StrTable = begin_children();
+  child_iterator StrTable = begin_children(false);
   child_iterator e = end_children();
   for (int i = 0; StrTable != e && i < 2; ++StrTable, ++i) {}
 
@@ -156,11 +193,15 @@ Archive::Archive(MemoryBuffer *source, error_code &ec)
   ec = object_error::success;
 }
 
-Archive::child_iterator Archive::begin_children() const {
+Archive::child_iterator Archive::begin_children(bool skip_internal) const {
   const char *Loc = Data->getBufferStart() + Magic.size();
   size_t Size = sizeof(ArchiveMemberHeader) +
     ToHeader(Loc)->getSize();
-  return Child(this, StringRef(Loc, Size));
+  Child c(this, StringRef(Loc, Size));
+  // Skip internals at the beginning of an archive.
+  if (skip_internal && isInternalMember(*ToHeader(Loc)))
+    return c.getNext();
+  return c;
 }
 
 Archive::child_iterator Archive::end_children() const {
-- 
2.34.1