Revert "[opaque pointer type] Pass GlobalAlias the actual pointer type rather than...

[oota-llvm.git] / lib / IR / User.cpp

diff --git a/lib/IR/User.cpp b/lib/IR/User.cpp
index 1084a505cfd0352cb389bd2dc283bc1404471b28..522722d701bac5b92c68892a8bad6ec2a1bc7014 100644 (file)
--- a/lib/IR/User.cpp
+++ b/lib/IR/User.cpp
@@ -41,6 +41,14 @@ void User::replaceUsesOfWith(Value *From, Value *To) {
 //===----------------------------------------------------------------------===//
 
 void User::allocHungoffUses(unsigned N, bool IsPhi) {
+  assert(HasHungOffUses && "alloc must have hung off uses");
+
+  static_assert(AlignOf<Use>::Alignment >= AlignOf<Use::UserRef>::Alignment,
+                "Alignment is insufficient for 'hung-off-uses' pieces");
+  static_assert(AlignOf<Use::UserRef>::Alignment >=
+                    AlignOf<BasicBlock *>::Alignment,
+                "Alignment is insufficient for 'hung-off-uses' pieces");
+
   // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
   // the User.
   size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
@@ -50,8 +58,6 @@ void User::allocHungoffUses(unsigned N, bool IsPhi) {
   Use *End = Begin + N;
   (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
   setOperandList(Use::initTags(Begin, End));
-  // Tag this operand list as being a hung off.
-  HasHungOffUses = true;
 }
 
 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
@@ -85,29 +91,49 @@ void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
 //                         User operator new Implementations
 //===----------------------------------------------------------------------===//
 
-void *User::operator new(size_t s, unsigned Us) {
+void *User::operator new(size_t Size, unsigned Us) {
   assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
-  void *Storage = ::operator new(s + sizeof(Use) * Us);
+  void *Storage = ::operator new(Size + sizeof(Use) * Us);
   Use *Start = static_cast<Use*>(Storage);
   Use *End = Start + Us;
   User *Obj = reinterpret_cast<User*>(End);
-  Obj->setOperandList(Start);
-  Obj->HasHungOffUses = false;
   Obj->NumUserOperands = Us;
+  Obj->HasHungOffUses = false;
   Use::initTags(Start, End);
   return Obj;
 }
 
+void *User::operator new(size_t Size) {
+  // Allocate space for a single Use*
+  void *Storage = ::operator new(Size + sizeof(Use *));
+  Use **HungOffOperandList = static_cast<Use **>(Storage);
+  User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1);
+  Obj->NumUserOperands = 0;
+  Obj->HasHungOffUses = true;
+  *HungOffOperandList = nullptr;
+  return Obj;
+}
+
 //===----------------------------------------------------------------------===//
 //                         User operator delete Implementation
 //===----------------------------------------------------------------------===//
 
 void User::operator delete(void *Usr) {
-  User *Start = static_cast<User*>(Usr);
-  Use *Storage = static_cast<Use*>(Usr) - Start->NumUserOperands;
-  // If there were hung-off uses, they will have been freed already and
-  // NumOperands reset to 0, so here we just free the User itself.
-  ::operator delete(Storage);
+  // Hung off uses use a single Use* before the User, while other subclasses
+  // use a Use[] allocated prior to the user.
+  User *Obj = static_cast<User *>(Usr);
+  if (Obj->HasHungOffUses) {
+    Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
+    // drop the hung off uses.
+    Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
+             /* Delete */ true);
+    ::operator delete(HungOffOperandList);
+  } else {
+    Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
+    Use::zap(Storage, Storage + Obj->NumUserOperands,
+             /* Delete */ false);
+    ::operator delete(Storage);
+  }
 }
 
 //===----------------------------------------------------------------------===//