From be9ab2682e3bd88424016121e72c4485964ca90a Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Wed, 22 Jul 2015 19:34:26 +0000
Subject: [PATCH] Fix fetching the symbol table of a thin archive.

We were trying to read it as an external file.

llvm-svn: 242926
---
 llvm/include/llvm/Object/Archive.h   |  2 ++
 llvm/lib/Object/Archive.cpp          | 17 +++++++++++------
 llvm/test/Object/archive-symtab.test | 11 +++++++++++
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/Object/Archive.h b/llvm/include/llvm/Object/Archive.h
index e5d59d8..d7f4655 100644
--- a/llvm/include/llvm/Object/Archive.h
+++ b/llvm/include/llvm/Object/Archive.h
@@ -62,6 +62,8 @@ public:
       return reinterpret_cast<const ArchiveMemberHeader *>(Data.data());
     }
 
+    bool isThinMember() const;
+
   public:
     Child(const Archive *Parent, const char *Start);
 
diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index a1e5eb2..941f72b 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -87,17 +87,17 @@ Archive::Child::Child(const Archive *Parent, const char *Start)
   if (!Start)
     return;
 
-  const ArchiveMemberHeader *Header =
-      reinterpret_cast<const ArchiveMemberHeader *>(Start);
   uint64_t Size = sizeof(ArchiveMemberHeader);
-  if (!Parent->IsThin || Header->getName() == "/" || Header->getName() == "//")
-    Size += Header->getSize();
   Data = StringRef(Start, Size);
+  if (!isThinMember()) {
+    Size += getRawSize();
+    Data = StringRef(Start, Size);
+  }
 
   // Setup StartOfFile and PaddingBytes.
   StartOfFile = sizeof(ArchiveMemberHeader);
   // Don't include attached name.
-  StringRef Name = Header->getName();
+  StringRef Name = getRawName();
   if (Name.startswith("#1/")) {
     uint64_t NameSize;
     if (Name.substr(3).rtrim(" ").getAsInteger(10, NameSize))
@@ -116,8 +116,13 @@ uint64_t Archive::Child::getRawSize() const {
   return getHeader()->getSize();
 }
 
+bool Archive::Child::isThinMember() const {
+  StringRef Name = getHeader()->getName();
+  return Parent->IsThin && Name != "/" && Name != "//";
+}
+
 ErrorOr<StringRef> Archive::Child::getBuffer() const {
-  if (!Parent->IsThin)
+  if (!isThinMember())
     return StringRef(Data.data() + StartOfFile, getSize());
   ErrorOr<StringRef> Name = getName();
   if (std::error_code EC = Name.getError())
diff --git a/llvm/test/Object/archive-symtab.test b/llvm/test/Object/archive-symtab.test
index 6e4c76f..8ba4ba0 100644
--- a/llvm/test/Object/archive-symtab.test
+++ b/llvm/test/Object/archive-symtab.test
@@ -8,6 +8,17 @@ CHECK-NEXT: foo in trivial-object-test2.elf-x86-64
 CHECK-NEXT: main in trivial-object-test2.elf-x86-64
 CHECK-NOT: bar
 
+
+RUN: rm -f %t.a
+RUN: llvm-ar rcT %t.a %p/Inputs/trivial-object-test.elf-x86-64 %p/Inputs/trivial-object-test2.elf-x86-64
+RUN: llvm-nm -M %t.a | FileCheck --check-prefix=THIN %s
+
+THIN: Archive map
+THIN-NEXT: main in {{.*}}/Inputs/trivial-object-test.elf-x86-64
+THIN-NEXT: foo in {{.*}}/Inputs/trivial-object-test2.elf-x86-64
+THIN-NEXT: main in {{.*}}/Inputs/trivial-object-test2.elf-x86-64
+
+
 CHECK: trivial-object-test.elf-x86-64:
 CHECK-NEXT:                  U SomeOtherFunction
 CHECK-NEXT: 0000000000000000 T main
-- 
2.7.4