From 6197f101bd0d753866f39268fb1f63e03eadce6f Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Mon, 5 May 2014 21:21:39 +0000
Subject: [PATCH] Simplify replacement map by avoiding duplicate values and
 ensuring the values it does contain are necessary.

Items were being redundantly added to the replacement map (both when the
declaration was created, and then again when its definition was
constructed) which caused extra handling to be required when walking the
map (as elements may've already been replaced due to prior entries). By
avoiding adding the duplicates, the checks in the replacement handling
can be replaced with assertions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208000 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGDebugInfo.cpp | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index f41fac80a2..4d763508ad 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -2093,9 +2093,7 @@ llvm::DIType CGDebugInfo::getOrCreateType(QualType Ty, llvm::DIFile Unit) {
   // types. We should probably just pull that out as a special case for the
   // "else" block below & skip the otherwise needless lookup.
   llvm::DIType TC = getTypeOrNull(Ty);
-  if (TC && TC.isForwardDecl())
-    ReplaceMap.push_back(std::make_pair(TyPtr, static_cast<llvm::Value*>(TC)));
-  else if (ObjCInterfaceDecl* Decl = getObjCInterfaceDecl(Ty)) {
+  if (ObjCInterfaceDecl *Decl = getObjCInterfaceDecl(Ty)) {
     // Interface types may have elements added to them by a
     // subsequent implementation or extension, so we keep them in
     // the ObjCInterfaceCache together with a checksum. Instead of
@@ -3382,21 +3380,17 @@ CGDebugInfo::getOrCreateNameSpace(const NamespaceDecl *NSDecl) {
 void CGDebugInfo::finalize() {
   for (std::vector<std::pair<void *, llvm::WeakVH> >::const_iterator VI
          = ReplaceMap.begin(), VE = ReplaceMap.end(); VI != VE; ++VI) {
-    llvm::DIType Ty, RepTy;
-    // Verify that the debug info still exists.
-    if (llvm::Value *V = VI->second)
-      Ty = llvm::DIType(cast<llvm::MDNode>(V));
+    assert(VI->second);
+    llvm::DIType Ty(cast<llvm::MDNode>(VI->second));
+    assert(Ty.isForwardDecl());
 
     llvm::DenseMap<void *, llvm::WeakVH>::iterator it =
-      TypeCache.find(VI->first);
-    if (it != TypeCache.end()) {
-      // Verify that the debug info still exists.
-      if (llvm::Value *V = it->second)
-        RepTy = llvm::DIType(cast<llvm::MDNode>(V));
-    }
+        TypeCache.find(VI->first);
+    assert(it != TypeCache.end());
+    assert(it->second);
+    llvm::DIType RepTy(cast<llvm::MDNode>(it->second));
 
-    if (Ty && Ty.isForwardDecl() && RepTy)
-      Ty.replaceAllUsesWith(RepTy);
+    Ty.replaceAllUsesWith(RepTy);
   }
 
   // We keep our own list of retained types, because we need to look
-- 
2.50.1