From 464f4ef2bdb47a44ffa2c4208296da641db7358d Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Tue, 3 May 2011 16:18:28 +0000
Subject: [PATCH] Use llvm.dbg.cu  named metadata to collect compile units.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130756 91177308-0d34-0410-b5e6-96231b3b80d8
---
 docs/SourceLevelDebugging.html | 4 +++-
 lib/Analysis/DIBuilder.cpp     | 4 ++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/docs/SourceLevelDebugging.html b/docs/SourceLevelDebugging.html
index c9ae0202def..4c4439fd59f 100644
--- a/docs/SourceLevelDebugging.html
+++ b/docs/SourceLevelDebugging.html
@@ -342,7 +342,9 @@ height="369">
    that produced it.</p>
 
 <p>Compile unit descriptors provide the root context for objects declared in a
-   specific compilation unit. File descriptors are defined using this context.</p>
+   specific compilation unit. File descriptors are defined using this context.
+   These descriptors are collected by a named metadata 
+   <tt>!llvm.dbg.cu</tt>.
 
 </div>
 
diff --git a/lib/Analysis/DIBuilder.cpp b/lib/Analysis/DIBuilder.cpp
index dc98c9e67a8..1375e497ac6 100644
--- a/lib/Analysis/DIBuilder.cpp
+++ b/lib/Analysis/DIBuilder.cpp
@@ -51,6 +51,10 @@ void DIBuilder::createCompileUnit(unsigned Lang, StringRef Filename,
     ConstantInt::get(Type::getInt32Ty(VMContext), RunTimeVer)
   };
   TheCU = DICompileUnit(MDNode::get(VMContext, Elts));
+
+  // Create a named metadata so that it is easier to find cu in a module.
+  NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu");
+  NMD->addOperand(TheCU);
 }
 
 /// createFile - Create a file descriptor to hold debugging information