1 files changed, 128 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Transforms/ObjCARC/ObjCARCExpand.cpp b/contrib/llvm/lib/Transforms/ObjCARC/ObjCARCExpand.cpp
new file mode 100644
index 0000000..39bf8f3
--- /dev/null
+++ b/contrib/llvm/lib/Transforms/ObjCARC/ObjCARCExpand.cpp
@@ -0,0 +1,128 @@
+//===- ObjCARCExpand.cpp - ObjC ARC Optimization --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file defines ObjC ARC optimizations. ARC stands for Automatic
+/// Reference Counting and is a system for managing reference counts for objects
+/// in Objective C.
+///
+/// This specific file deals with early optimizations which perform certain
+/// cleanup operations.
+///
+/// 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.
+///
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "objc-arc-expand"
+
+#include "ObjCARC.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Pass.h"
+#include "llvm/PassAnalysisSupport.h"
+#include "llvm/PassRegistry.h"
+#include "llvm/PassSupport.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+  class Module;
+}
+
+using namespace llvm;
+using namespace llvm::objcarc;
+
+namespace {
+  /// \brief Early ARC transformations.
+  class ObjCARCExpand : public FunctionPass {
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+    virtual bool doInitialization(Module &M);
+    virtual bool runOnFunction(Function &F);
+
+    /// A flag indicating whether this optimization pass should run.
+    bool Run;
+
+  public:
+    static char ID;
+    ObjCARCExpand() : FunctionPass(ID) {
+      initializeObjCARCExpandPass(*PassRegistry::getPassRegistry());
+    }
+  };
+}
+
+char ObjCARCExpand::ID = 0;
+INITIALIZE_PASS(ObjCARCExpand,
+                "objc-arc-expand", "ObjC ARC expansion", false, false)
+
+Pass *llvm::createObjCARCExpandPass() {
+  return new ObjCARCExpand();
+}
+
+void ObjCARCExpand::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.setPreservesCFG();
+}
+
+bool ObjCARCExpand::doInitialization(Module &M) {
+  Run = ModuleHasARC(M);
+  return false;
+}
+
+bool ObjCARCExpand::runOnFunction(Function &F) {
+  if (!EnableARCOpts)
+    return false;
+
+  // If nothing in the Module uses ARC, don't do anything.
+  if (!Run)
+    return false;
+
+  bool Changed = false;
+
+  DEBUG(dbgs() << "ObjCARCExpand: Visiting Function: " << F.getName() << "\n");
+
+  for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ++I) {
+    Instruction *Inst = &*I;
+
+    DEBUG(dbgs() << "ObjCARCExpand: Visiting: " << *Inst << "\n");
+
+    switch (GetBasicInstructionClass(Inst)) {
+    case IC_Retain:
+    case IC_RetainRV:
+    case IC_Autorelease:
+    case IC_AutoreleaseRV:
+    case IC_FusedRetainAutorelease:
+    case IC_FusedRetainAutoreleaseRV: {
+      // These calls return their argument verbatim, as a low-level
+      // optimization. However, this makes high-level optimizations
+      // harder. Undo any uses of this optimization that the front-end
+      // emitted here. We'll redo them in the contract pass.
+      Changed = true;
+      Value *Value = cast<CallInst>(Inst)->getArgOperand(0);
+      DEBUG(dbgs() << "ObjCARCExpand: Old = " << *Inst << "\n"
+                      "               New = " << *Value << "\n");
+      Inst->replaceAllUsesWith(Value);
+      break;
+    }
+    default:
+      break;
+    }
+  }
+
+  DEBUG(dbgs() << "ObjCARCExpand: Finished List.\n\n");
+
+  return Changed;
+}