From 4841121580df86b327013d1fab2a9339be487bce Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Wed, 6 Apr 2011 06:49:59 +0000
Subject: [PATCH] Add an empty key for DebugLoc so that you can store an empty
 DebugLoc in a DenseMap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128994 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/DebugLoc.h | 14 +++++++++++---
 lib/VMCore/DebugLoc.cpp         |  2 +-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/llvm/Support/DebugLoc.h b/include/llvm/Support/DebugLoc.h
index 764591cfede..8d19e300ec2 100644
--- a/include/llvm/Support/DebugLoc.h
+++ b/include/llvm/Support/DebugLoc.h
@@ -27,14 +27,22 @@ namespace llvm {
   class DebugLoc {
     friend struct DenseMapInfo<DebugLoc>;
 
-    /// getTombstoneKey() - A private constructor that returns an unknown that
-    /// is distinguishable from the usual one.
-    static DebugLoc getTombstoneKey() {
+    /// getEmptyKey() - A private constructor that returns an unknown that is
+    /// not equal to the tombstone key or DebugLoc().
+    static DebugLoc getEmptyKey() {
       DebugLoc DL;
       DL.LineCol = -1;
       return DL;
     }
 
+    /// getTombstoneKey() - A private constructor that returns an unknown that
+    /// is not equal to the empty key or DebugLoc().
+    static DebugLoc getTombstoneKey() {
+      DebugLoc DL;
+      DL.LineCol = -2;
+      return DL;
+    }
+
     /// LineCol - This 32-bit value encodes the line and column number for the
     /// location, encoded as 24-bits for line and 8 bits for col.  A value of 0
     /// for either means unknown.
diff --git a/lib/VMCore/DebugLoc.cpp b/lib/VMCore/DebugLoc.cpp
index cb077cb4374..35691627f49 100644
--- a/lib/VMCore/DebugLoc.cpp
+++ b/lib/VMCore/DebugLoc.cpp
@@ -133,7 +133,7 @@ DebugLoc DebugLoc::getFromDILocation(MDNode *N) {
 //===----------------------------------------------------------------------===//
 
 DebugLoc DenseMapInfo<DebugLoc>::getEmptyKey() {
-  return DebugLoc();
+  return DebugLoc::getEmptyKey();
 }
 
 DebugLoc DenseMapInfo<DebugLoc>::getTombstoneKey() {