1 files changed, 107 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARC.h b/llvm/lib/Transforms/ObjCARC/ObjCARC.h
new file mode 100644
index 000000000000..d465630800b9
--- /dev/null
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARC.h
@@ -0,0 +1,107 @@
+//===- ObjCARC.h - ObjC ARC Optimization --------------*- C++ -*-----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file defines common definitions/declarations used by the ObjC ARC
+/// Optimizer. ARC stands for Automatic Reference Counting and is a system for
+/// managing reference counts for objects in Objective C.
+///
+/// WARNING: This file knows about certain library functions. It recognizes them
+/// by name, and hardwires knowledge of their semantics.
+///
+/// WARNING: This file knows about how certain Objective-C library functions are
+/// used. Naive LLVM IR transformations which would otherwise be
+/// behavior-preserving may break these assumptions.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H
+#define LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARC_H
+
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/ObjCARC.h"
+
+namespace llvm {
+class raw_ostream;
+}
+
+namespace llvm {
+namespace objcarc {
+
+/// Erase the given instruction.
+///
+/// Many ObjC calls return their argument verbatim,
+/// so if it's such a call and the return value has users, replace them with the
+/// argument value.
+///
+static inline void EraseInstruction(Instruction *CI) {
+  Value *OldArg = cast<CallInst>(CI)->getArgOperand(0);
+
+  bool Unused = CI->use_empty();
+
+  if (!Unused) {
+    // Replace the return value with the argument.
+    assert((IsForwarding(GetBasicARCInstKind(CI)) ||
+            (IsNoopOnNull(GetBasicARCInstKind(CI)) &&
+             IsNullOrUndef(OldArg->stripPointerCasts()))) &&
+           "Can't delete non-forwarding instruction with users!");
+    CI->replaceAllUsesWith(OldArg);
+  }
+
+  CI->eraseFromParent();
+
+  if (Unused)
+    RecursivelyDeleteTriviallyDeadInstructions(OldArg);
+}
+
+/// If Inst is a ReturnRV and its operand is a call or invoke, return the
+/// operand. Otherwise return null.
+static inline const Instruction *getreturnRVOperand(const Instruction &Inst,
+                                                    ARCInstKind Class) {
+  if (Class != ARCInstKind::RetainRV)
+    return nullptr;
+
+  const auto *Opnd = Inst.getOperand(0)->stripPointerCasts();
+  if (const auto *C = dyn_cast<CallInst>(Opnd))
+    return C;
+  return dyn_cast<InvokeInst>(Opnd);
+}
+
+/// Return the list of PHI nodes that are equivalent to PN.
+template<class PHINodeTy, class VectorTy>
+void getEquivalentPHIs(PHINodeTy &PN, VectorTy &PHIList) {
+  auto *BB = PN.getParent();
+  for (auto &P : BB->phis()) {
+    if (&P == &PN) // Do not add PN to the list.
+      continue;
+    unsigned I = 0, E = PN.getNumIncomingValues();
+    for (; I < E; ++I) {
+      auto *BB = PN.getIncomingBlock(I);
+      auto *PNOpnd = PN.getIncomingValue(I)->stripPointerCasts();
+      auto *POpnd = P.getIncomingValueForBlock(BB)->stripPointerCasts();
+      if (PNOpnd != POpnd)
+        break;
+    }
+    if (I == E)
+      PHIList.push_back(&P);
+  }
+}
+
+} // end namespace objcarc
+} // end namespace llvm
+
+#endif