X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FIR%2FUser.cpp;h=a75abe6938c99f0305ee101f0add5d1e18386934;hb=9443e66cd9fdef72cc7311019b6eb95ba56396db;hp=d65935204771d2bfa7aaf087a8f484b859b31346;hpb=ea423677ca81dbc7db43b040ce02c4aa3ccc119f;p=oota-llvm.git

diff --git a/lib/IR/User.cpp b/lib/IR/User.cpp
index d6593520477..a75abe6938c 100644
--- 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);
@@ -49,9 +57,7 @@ void User::allocHungoffUses(unsigned N, bool IsPhi) {
   Use *Begin = static_cast<Use*>(::operator new(size));
   Use *End = Begin + N;
   (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
-  OperandList = Use::initTags(Begin, End);
-  // Tag this operand list as being a hung off.
-  HasHungOffUses = true;
+  setOperandList(Use::initTags(Begin, End));
 }
 
 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
@@ -63,9 +69,9 @@ void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
   // space to copy the old uses in to the new space.
   assert(NewNumUses > OldNumUses && "realloc must grow num uses");
 
-  Use *OldOps = OperandList;
+  Use *OldOps = getOperandList();
   allocHungoffUses(NewNumUses, IsPhi);
-  Use *NewOps = OperandList;
+  Use *NewOps = getOperandList();
 
   // Now copy from the old operands list to the new one.
   std::copy(OldOps, OldOps + OldNumUses, NewOps);
@@ -81,19 +87,79 @@ void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
   Use::zap(OldOps, OldOps + OldNumUses, true);
 }
 
+
+// This is a private struct used by `User` to track the co-allocated descriptor
+// section.
+struct DescriptorInfo {
+  intptr_t SizeInBytes;
+};
+
+ArrayRef<const uint8_t> User::getDescriptor() const {
+  auto MutableARef = const_cast<User *>(this)->getDescriptor();
+  return {MutableARef.begin(), MutableARef.end()};
+}
+
+MutableArrayRef<uint8_t> User::getDescriptor() {
+  assert(HasDescriptor && "Don't call otherwise!");
+  assert(!HasHungOffUses && "Invariant!");
+
+  auto *DI = reinterpret_cast<DescriptorInfo *>(getIntrusiveOperands()) - 1;
+  assert(DI->SizeInBytes != 0 && "Should not have had a descriptor otherwise!");
+
+  return MutableArrayRef<uint8_t>(
+      reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes, DI->SizeInBytes);
+}
+
 //===----------------------------------------------------------------------===//
 //                         User operator new Implementations
 //===----------------------------------------------------------------------===//
 
-void *User::operator new(size_t s, unsigned Us) {
-  void *Storage = ::operator new(s + sizeof(Use) * Us);
-  Use *Start = static_cast<Use*>(Storage);
+void *User::allocateFixedOperandUser(size_t Size, unsigned Us,
+                                     unsigned DescBytes) {
+  assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
+
+  static_assert(sizeof(DescriptorInfo) % sizeof(void *) == 0, "Required below");
+
+  unsigned DescBytesToAllocate =
+      DescBytes == 0 ? 0 : (DescBytes + sizeof(DescriptorInfo));
+  assert(DescBytesToAllocate % sizeof(void *) == 0 &&
+         "We need this to satisfy alignment constraints for Uses");
+
+  uint8_t *Storage = static_cast<uint8_t *>(
+      ::operator new(Size + sizeof(Use) * Us + DescBytesToAllocate));
+  Use *Start = reinterpret_cast<Use *>(Storage + DescBytesToAllocate);
   Use *End = Start + Us;
   User *Obj = reinterpret_cast<User*>(End);
-  Obj->OperandList = Start;
+  Obj->NumUserOperands = Us;
   Obj->HasHungOffUses = false;
-  Obj->NumOperands = Us;
+  Obj->HasDescriptor = DescBytes != 0;
   Use::initTags(Start, End);
+
+  if (DescBytes != 0) {
+    auto *DescInfo = reinterpret_cast<DescriptorInfo *>(Storage + DescBytes);
+    DescInfo->SizeInBytes = DescBytes;
+  }
+
+  return Obj;
+}
+
+void *User::operator new(size_t Size, unsigned Us) {
+  return allocateFixedOperandUser(Size, Us, 0);
+}
+
+void *User::operator new(size_t Size, unsigned Us, unsigned DescBytes) {
+  return allocateFixedOperandUser(Size, Us, DescBytes);
+}
+
+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;
+  Obj->HasDescriptor = false;
+  *HungOffOperandList = nullptr;
   return Obj;
 }
 
@@ -102,11 +168,30 @@ void *User::operator new(size_t s, unsigned Us) {
 //===----------------------------------------------------------------------===//
 
 void User::operator delete(void *Usr) {
-  User *Start = static_cast<User*>(Usr);
-  Use *Storage = static_cast<Use*>(Usr) - Start->NumOperands;
-  // 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) {
+    assert(!Obj->HasDescriptor && "not supported!");
+
+    Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
+    // drop the hung off uses.
+    Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
+             /* Delete */ true);
+    ::operator delete(HungOffOperandList);
+  } else if (Obj->HasDescriptor) {
+    Use *UseBegin = static_cast<Use *>(Usr) - Obj->NumUserOperands;
+    Use::zap(UseBegin, UseBegin + Obj->NumUserOperands, /* Delete */ false);
+
+    auto *DI = reinterpret_cast<DescriptorInfo *>(UseBegin) - 1;
+    uint8_t *Storage = reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes;
+    ::operator delete(Storage);
+  } else {
+    Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
+    Use::zap(Storage, Storage + Obj->NumUserOperands,
+             /* Delete */ false);
+    ::operator delete(Storage);
+  }
 }
 
 //===----------------------------------------------------------------------===//