From 9085750d3126618ab1b3a4104c34bc504f8b09f4 Mon Sep 17 00:00:00 2001
From: Owen Anderson <resistor@mac.com>
Date: Fri, 21 Aug 2009 19:59:12 +0000
Subject: [PATCH] Try again at privatizing the layout info map, with a
 rewritten patch. This preserves the existing behavior much more closely than
 my previous attempt.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79663 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/TargetData.h |  6 ++-
 lib/Target/TargetData.cpp        | 64 +++++++++-----------------------
 2 files changed, 22 insertions(+), 48 deletions(-)

diff --git a/include/llvm/Target/TargetData.h b/include/llvm/Target/TargetData.h
index 23775be70f9..f8ea64b4ea6 100644
--- a/include/llvm/Target/TargetData.h
+++ b/include/llvm/Target/TargetData.h
@@ -91,6 +91,9 @@ private:
    */
   static const TargetAlignElem InvalidAlignmentElem;
 
+  // Opaque pointer for the StructType -> StructLayout map.
+  mutable void* LayoutMap;
+
   //! Set/initialize target alignments
   void setAlignment(AlignTypeEnum align_type, unsigned char abi_align,
                     unsigned char pref_align, uint32_t bit_width);
@@ -132,7 +135,8 @@ public:
     PointerMemSize(TD.PointerMemSize),
     PointerABIAlign(TD.PointerABIAlign),
     PointerPrefAlign(TD.PointerPrefAlign),
-    Alignments(TD.Alignments)
+    Alignments(TD.Alignments),
+    LayoutMap(0)
   { }
 
   ~TargetData();  // Not virtual, do not subclass this class
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index baef9c8fa74..5bcd6583635 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -172,6 +172,7 @@ const TargetAlignElem TargetData::InvalidAlignmentElem =
 void TargetData::init(const std::string &TargetDescription) {
   std::string temp = TargetDescription;
   
+  LayoutMap = 0;
   LittleEndian = false;
   PointerMemSize = 8;
   PointerABIAlign   = 8;
@@ -317,61 +318,30 @@ unsigned TargetData::getAlignmentInfo(AlignTypeEnum AlignType,
                  : Alignments[BestMatchIdx].PrefAlign;
 }
 
-namespace {
-
-/// LayoutInfo - The lazy cache of structure layout information maintained by
-/// TargetData.  Note that the struct types must have been free'd before
-/// llvm_shutdown is called (and thus this is deallocated) because all the
-/// targets with cached elements should have been destroyed.
-///
-typedef std::pair<const TargetData*,const StructType*> LayoutKey;
-
-struct DenseMapLayoutKeyInfo {
-  static inline LayoutKey getEmptyKey() { return LayoutKey(0, 0); }
-  static inline LayoutKey getTombstoneKey() {
-    return LayoutKey((TargetData*)(intptr_t)-1, 0);
-  }
-  static unsigned getHashValue(const LayoutKey &Val) {
-    return DenseMapInfo<void*>::getHashValue(Val.first) ^
-           DenseMapInfo<void*>::getHashValue(Val.second);
-  }
-  static bool isEqual(const LayoutKey &LHS, const LayoutKey &RHS) {
-    return LHS == RHS;
-  }
-
-  static bool isPod() { return true; }
-};
-
-typedef DenseMap<LayoutKey, StructLayout*, DenseMapLayoutKeyInfo> LayoutInfoTy;
-
-}
-
-static ManagedStatic<LayoutInfoTy> LayoutInfo;
-static ManagedStatic<sys::SmartMutex<true> > LayoutLock;
+typedef DenseMap<const StructType*, StructLayout*>LayoutInfoTy;
 
 TargetData::~TargetData() {
-  if (!LayoutInfo.isConstructed())
+  if (!LayoutMap)
     return;
   
-  sys::SmartScopedLock<true> Lock(*LayoutLock);
   // Remove any layouts for this TD.
-  LayoutInfoTy &TheMap = *LayoutInfo;
+  LayoutInfoTy &TheMap = *static_cast<LayoutInfoTy*>(LayoutMap);
   for (LayoutInfoTy::iterator I = TheMap.begin(), E = TheMap.end(); I != E; ) {
-    if (I->first.first == this) {
-      I->second->~StructLayout();
-      free(I->second);
-      TheMap.erase(I++);
-    } else {
-      ++I;
-    }
+    I->second->~StructLayout();
+    free(I->second);
+    TheMap.erase(I++);
   }
+  
+  delete static_cast<LayoutInfoTy*>(LayoutMap);
 }
 
 const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
-  LayoutInfoTy &TheMap = *LayoutInfo;
+  if (!LayoutMap)
+    LayoutMap = static_cast<void*>(new LayoutInfoTy());
+  
+  LayoutInfoTy &TheMap = *static_cast<LayoutInfoTy*>(LayoutMap);
   
-  sys::SmartScopedLock<true> Lock(*LayoutLock);
-  StructLayout *&SL = TheMap[LayoutKey(this, Ty)];
+  StructLayout *&SL = TheMap[Ty];
   if (SL) return SL;
 
   // Otherwise, create the struct layout.  Because it is variable length, we 
@@ -393,10 +363,10 @@ const StructLayout *TargetData::getStructLayout(const StructType *Ty) const {
 /// removed, this method must be called whenever a StructType is removed to
 /// avoid a dangling pointer in this cache.
 void TargetData::InvalidateStructLayoutInfo(const StructType *Ty) const {
-  if (!LayoutInfo.isConstructed()) return;  // No cache.
+  if (!LayoutMap) return;  // No cache.
   
-  sys::SmartScopedLock<true> Lock(*LayoutLock);
-  LayoutInfoTy::iterator I = LayoutInfo->find(LayoutKey(this, Ty));
+  LayoutInfoTy* LayoutInfo = static_cast<LayoutInfoTy*>(LayoutMap);
+  LayoutInfoTy::iterator I = LayoutInfo->find(Ty);
   if (I == LayoutInfo->end()) return;
   
   I->second->~StructLayout();
-- 
2.34.1