[ARC] Pull the ObjC ARC components that really serve the role of

analyses into LLVM's Analysis library rather than having them in
a Transforms library.

This is motivated by the need to have the core AliasAnalysis
infrastructure be aware of the ObjCARCAliasAnalysis. However, it also
seems like a nice and clean separation. Everything was very easy to move
and this doesn't create much clutter in the analysis library IMO.

Differential Revision: http://reviews.llvm.org/D12133

llvm-svn: 245541

include/llvm/Analysis/ObjCARCAliasAnalysis.h

@@ -1,4 +1,4 @@
-//===- ObjCARCAliasAnalysis.h - ObjC ARC Optimization -*- C++ -*-----------===//
+//===- ObjCARCAliasAnalysis.h - ObjC ARC Alias Analysis ---------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -20,8 +20,8 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARCALIASANALYSIS_H
-#define LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARCALIASANALYSIS_H
+#ifndef LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
+#define LLVM_ANALYSIS_OBJCARCALIASANALYSIS_H
 
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Pass.h"

include/llvm/Analysis/ObjCARCAnalysisUtils.h

@@ -0,0 +1,287 @@
+//===- ObjCARCAnalysisUtils.h - ObjC ARC Analysis Utilities -----*- C++ -*-===//
+//
+//                     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 common analysis utilities 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_ANALYSIS_OBJCARCANALYSISUTILS_H
+#define LLVM_LIB_ANALYSIS_OBJCARCANALYSISUTILS_H
+
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
+#include "llvm/Analysis/Passes.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"
+#include "llvm/Transforms/Utils/Local.h"
+
+namespace llvm {
+class raw_ostream;
+}
+
+namespace llvm {
+namespace objcarc {
+
+/// \brief A handy option to enable/disable all ARC Optimizations.
+extern bool EnableARCOpts;
+
+/// \brief Test if the given module looks interesting to run ARC optimization
+/// on.
+inline bool ModuleHasARC(const Module &M) {
+  return
+    M.getNamedValue("objc_retain") ||
+    M.getNamedValue("objc_release") ||
+    M.getNamedValue("objc_autorelease") ||
+    M.getNamedValue("objc_retainAutoreleasedReturnValue") ||
+    M.getNamedValue("objc_retainBlock") ||
+    M.getNamedValue("objc_autoreleaseReturnValue") ||
+    M.getNamedValue("objc_autoreleasePoolPush") ||
+    M.getNamedValue("objc_loadWeakRetained") ||
+    M.getNamedValue("objc_loadWeak") ||
+    M.getNamedValue("objc_destroyWeak") ||
+    M.getNamedValue("objc_storeWeak") ||
+    M.getNamedValue("objc_initWeak") ||
+    M.getNamedValue("objc_moveWeak") ||
+    M.getNamedValue("objc_copyWeak") ||
+    M.getNamedValue("objc_retainedObject") ||
+    M.getNamedValue("objc_unretainedObject") ||
+    M.getNamedValue("objc_unretainedPointer") ||
+    M.getNamedValue("clang.arc.use");
+}
+
+/// \brief This is a wrapper around getUnderlyingObject which also knows how to
+/// look through objc_retain and objc_autorelease calls, which we know to return
+/// their argument verbatim.
+inline const Value *GetUnderlyingObjCPtr(const Value *V,
+                                                const DataLayout &DL) {
+  for (;;) {
+    V = GetUnderlyingObject(V, DL);
+    if (!IsForwarding(GetBasicARCInstKind(V)))
+      break;
+    V = cast<CallInst>(V)->getArgOperand(0);
+  }
+
+  return V;
+}
+
+/// The RCIdentity root of a value \p V is a dominating value U for which
+/// retaining or releasing U is equivalent to retaining or releasing V. In other
+/// words, ARC operations on \p V are equivalent to ARC operations on \p U.
+///
+/// We use this in the ARC optimizer to make it easier to match up ARC
+/// operations by always mapping ARC operations to RCIdentityRoots instead of
+/// pointers themselves.
+///
+/// The two ways that we see RCIdentical values in ObjC are via:
+///
+///   1. PointerCasts
+///   2. Forwarding Calls that return their argument verbatim.
+///
+/// Thus this function strips off pointer casts and forwarding calls. *NOTE*
+/// This implies that two RCIdentical values must alias.
+inline const Value *GetRCIdentityRoot(const Value *V) {
+  for (;;) {
+    V = V->stripPointerCasts();
+    if (!IsForwarding(GetBasicARCInstKind(V)))
+      break;
+    V = cast<CallInst>(V)->getArgOperand(0);
+  }
+  return V;
+}
+
+/// Helper which calls const Value *GetRCIdentityRoot(const Value *V) and just
+/// casts away the const of the result. For documentation about what an
+/// RCIdentityRoot (and by extension GetRCIdentityRoot is) look at that
+/// function.
+inline Value *GetRCIdentityRoot(Value *V) {
+  return const_cast<Value *>(GetRCIdentityRoot((const Value *)V));
+}
+
+/// \brief Assuming the given instruction is one of the special calls such as
+/// objc_retain or objc_release, return the RCIdentity root of the argument of
+/// the call.
+inline Value *GetArgRCIdentityRoot(Value *Inst) {
+  return GetRCIdentityRoot(cast<CallInst>(Inst)->getArgOperand(0));
+}
+
+inline bool IsNullOrUndef(const Value *V) {
+  return isa<ConstantPointerNull>(V) || isa<UndefValue>(V);
+}
+
+inline bool IsNoopInstruction(const Instruction *I) {
+  return isa<BitCastInst>(I) ||
+    (isa<GetElementPtrInst>(I) &&
+     cast<GetElementPtrInst>(I)->hasAllZeroIndices());
+}
+
+/// \brief Test whether the given value is possible a retainable object pointer.
+inline bool IsPotentialRetainableObjPtr(const Value *Op) {
+  // Pointers to static or stack storage are not valid retainable object
+  // pointers.
+  if (isa<Constant>(Op) || isa<AllocaInst>(Op))
+    return false;
+  // Special arguments can not be a valid retainable object pointer.
+  if (const Argument *Arg = dyn_cast<Argument>(Op))
+    if (Arg->hasByValAttr() ||
+        Arg->hasInAllocaAttr() ||
+        Arg->hasNestAttr() ||
+        Arg->hasStructRetAttr())
+      return false;
+  // Only consider values with pointer types.
+  //
+  // It seemes intuitive to exclude function pointer types as well, since
+  // functions are never retainable object pointers, however clang occasionally
+  // bitcasts retainable object pointers to function-pointer type temporarily.
+  PointerType *Ty = dyn_cast<PointerType>(Op->getType());
+  if (!Ty)
+    return false;
+  // Conservatively assume anything else is a potential retainable object
+  // pointer.
+  return true;
+}
+
+inline bool IsPotentialRetainableObjPtr(const Value *Op,
+                                               AliasAnalysis &AA) {
+  // First make the rudimentary check.
+  if (!IsPotentialRetainableObjPtr(Op))
+    return false;
+
+  // Objects in constant memory are not reference-counted.
+  if (AA.pointsToConstantMemory(Op))
+    return false;
+
+  // Pointers in constant memory are not pointing to reference-counted objects.
+  if (const LoadInst *LI = dyn_cast<LoadInst>(Op))
+    if (AA.pointsToConstantMemory(LI->getPointerOperand()))
+      return false;
+
+  // Otherwise assume the worst.
+  return true;
+}
+
+/// \brief Helper for GetARCInstKind. Determines what kind of construct CS
+/// is.
+inline ARCInstKind GetCallSiteClass(ImmutableCallSite CS) {
+  for (ImmutableCallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
+       I != E; ++I)
+    if (IsPotentialRetainableObjPtr(*I))
+      return CS.onlyReadsMemory() ? ARCInstKind::User : ARCInstKind::CallOrUser;
+
+  return CS.onlyReadsMemory() ? ARCInstKind::None : ARCInstKind::Call;
+}
+
+/// \brief Return true if this value refers to a distinct and identifiable
+/// object.
+///
+/// This is similar to AliasAnalysis's isIdentifiedObject, except that it uses
+/// special knowledge of ObjC conventions.
+inline bool IsObjCIdentifiedObject(const Value *V) {
+  // Assume that call results and arguments have their own "provenance".
+  // Constants (including GlobalVariables) and Allocas are never
+  // reference-counted.
+  if (isa<CallInst>(V) || isa<InvokeInst>(V) ||
+      isa<Argument>(V) || isa<Constant>(V) ||
+      isa<AllocaInst>(V))
+    return true;
+
+  if (const LoadInst *LI = dyn_cast<LoadInst>(V)) {
+    const Value *Pointer =
+      GetRCIdentityRoot(LI->getPointerOperand());
+    if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(Pointer)) {
+      // A constant pointer can't be pointing to an object on the heap. It may
+      // be reference-counted, but it won't be deleted.
+      if (GV->isConstant())
+        return true;
+      StringRef Name = GV->getName();
+      // These special variables are known to hold values which are not
+      // reference-counted pointers.
+      if (Name.startswith("\01l_objc_msgSend_fixup_"))
+        return true;
+
+      StringRef Section = GV->getSection();
+      if (Section.find("__message_refs") != StringRef::npos ||
+          Section.find("__objc_classrefs") != StringRef::npos ||
+          Section.find("__objc_superrefs") != StringRef::npos ||
+          Section.find("__objc_methname") != StringRef::npos ||
+          Section.find("__cstring") != StringRef::npos)
+        return true;
+    }
+  }
+
+  return false;
+}
+
+enum class ARCMDKindID {
+  ImpreciseRelease,
+  CopyOnEscape,
+  NoObjCARCExceptions,
+};
+
+/// A cache of MDKinds used by various ARC optimizations.
+class ARCMDKindCache {
+  Module *M;
+
+  /// The Metadata Kind for clang.imprecise_release metadata.
+  llvm::Optional<unsigned> ImpreciseReleaseMDKind;
+
+  /// The Metadata Kind for clang.arc.copy_on_escape metadata.
+  llvm::Optional<unsigned> CopyOnEscapeMDKind;
+
+  /// The Metadata Kind for clang.arc.no_objc_arc_exceptions metadata.
+  llvm::Optional<unsigned> NoObjCARCExceptionsMDKind;
+
+public:
+  void init(Module *Mod) {
+    M = Mod;
+    ImpreciseReleaseMDKind = NoneType::None;
+    CopyOnEscapeMDKind = NoneType::None;
+    NoObjCARCExceptionsMDKind = NoneType::None;
+  }
+
+  unsigned get(ARCMDKindID ID) {
+    switch (ID) {
+    case ARCMDKindID::ImpreciseRelease:
+      if (!ImpreciseReleaseMDKind)
+        ImpreciseReleaseMDKind =
+            M->getContext().getMDKindID("clang.imprecise_release");
+      return *ImpreciseReleaseMDKind;
+    case ARCMDKindID::CopyOnEscape:
+      if (!CopyOnEscapeMDKind)
+        CopyOnEscapeMDKind =
+            M->getContext().getMDKindID("clang.arc.copy_on_escape");
+      return *CopyOnEscapeMDKind;
+    case ARCMDKindID::NoObjCARCExceptions:
+      if (!NoObjCARCExceptionsMDKind)
+        NoObjCARCExceptionsMDKind =
+            M->getContext().getMDKindID("clang.arc.no_objc_arc_exceptions");
+      return *NoObjCARCExceptionsMDKind;
+    }
+    llvm_unreachable("Covered switch isn't covered?!");
+  }
+};
+
+} // end namespace objcarc
+} // end namespace llvm
+
+#endif

include/llvm/Analysis/ObjCARCInstKind.h

@@ -1,4 +1,4 @@
-//===--- ARCInstKind.h - ARC instruction equivalence classes -*- C++ -*----===//
+//===- ObjCARCInstKind.h - ARC instruction equivalence classes --*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,8 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_ARCINSTKIND_H
-#define LLVM_LIB_TRANSFORMS_OBJCARC_ARCINSTKIND_H
+#ifndef LLVM_ANALYSIS_OBJCARCINSTKIND_H
+#define LLVM_ANALYSIS_OBJCARCINSTKIND_H
 
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Function.h"
@@ -98,7 +98,7 @@ ARCInstKind GetFunctionClass(const Function *F);
 /// This is similar to GetARCInstKind except that it only detects objc
 /// runtime calls. This allows it to be faster.
 ///
-static inline ARCInstKind GetBasicARCInstKind(const Value *V) {
+inline ARCInstKind GetBasicARCInstKind(const Value *V) {
   if (const CallInst *CI = dyn_cast<CallInst>(V)) {
     if (const Function *F = CI->getCalledFunction())
       return GetFunctionClass(F);

lib/Analysis/Analysis.cpp

@@ -61,6 +61,7 @@ void llvm::initializeAnalysis(PassRegistry &Registry) {
   initializeMemDerefPrinterPass(Registry);
   initializeMemoryDependenceAnalysisPass(Registry);
   initializeModuleDebugInfoPrinterPass(Registry);
+  initializeObjCARCAliasAnalysisPass(Registry);
   initializePostDominatorTreePass(Registry);
   initializeRegionInfoPassPass(Registry);
   initializeRegionViewerPass(Registry);

lib/Analysis/CMakeLists.txt

@@ -49,6 +49,9 @@ add_llvm_library(LLVMAnalysis
   MemoryLocation.cpp
   ModuleDebugInfoPrinter.cpp
   NoAliasAnalysis.cpp
+  ObjCARCAliasAnalysis.cpp
+  ObjCARCAnalysisUtils.cpp
+  ObjCARCInstKind.cpp
   OrderedBasicBlock.cpp
   PHITransAddr.cpp
   PostDominators.cpp

lib/Analysis/ObjCARCAliasAnalysis.cpp

@@ -20,8 +20,8 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#include "ObjCARC.h"
-#include "ObjCARCAliasAnalysis.h"
+#include "llvm/Analysis/ObjCARCAliasAnalysis.h"
+#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Value.h"

lib/Analysis/ObjCARCAnalysisUtils.cpp

@@ -0,0 +1,28 @@
+//===- ObjCARCAnalysisUtils.cpp -------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements common infrastructure for libLLVMObjCARCOpts.a, which
+// implements several scalar transformations over the LLVM intermediate
+// representation, including the C bindings for that library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
+#include "llvm/Support/CommandLine.h"
+
+using namespace llvm;
+using namespace llvm::objcarc;
+
+/// \brief A handy option to enable/disable all ARC Optimizations.
+bool llvm::objcarc::EnableARCOpts;
+static cl::opt<bool, true>
+EnableARCOptimizations("enable-objc-arc-opts",
+                       cl::desc("enable/disable all ARC Optimizations"),
+                       cl::location(EnableARCOpts),
+                       cl::init(true));

lib/Analysis/ObjCARCInstKind.cpp

@@ -19,7 +19,9 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#include "ObjCARC.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
+#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
+#include "llvm/ADT/StringSwitch.h"
 #include "llvm/IR/Intrinsics.h"
 
 using namespace llvm;

lib/Transforms/ObjCARC/CMakeLists.txt

@@ -3,8 +3,6 @@ add_llvm_library(LLVMObjCARCOpts
   ObjCARCOpts.cpp
   ObjCARCExpand.cpp
   ObjCARCAPElim.cpp
-  ObjCARCAliasAnalysis.cpp
-  ARCInstKind.cpp
   ObjCARCContract.cpp
   DependencyAnalysis.cpp
   ProvenanceAnalysis.cpp

lib/Transforms/ObjCARC/ObjCARC.cpp

@@ -26,14 +26,6 @@ namespace llvm {
 using namespace llvm;
 using namespace llvm::objcarc;
 
-/// \brief A handy option to enable/disable all ARC Optimizations.
-bool llvm::objcarc::EnableARCOpts;
-static cl::opt<bool, true>
-EnableARCOptimizations("enable-objc-arc-opts",
-                       cl::desc("enable/disable all ARC Optimizations"),
-                       cl::location(EnableARCOpts),
-                       cl::init(true));
-
 /// initializeObjCARCOptsPasses - Initialize all passes linked into the
 /// ObjCARCOpts library.
 void llvm::initializeObjCARCOpts(PassRegistry &Registry) {

lib/Transforms/ObjCARC/ObjCARC.h

@@ -26,6 +26,8 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/ObjCARCAnalysisUtils.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/CallSite.h"
@@ -34,7 +36,6 @@
 #include "llvm/Pass.h"
 #include "llvm/Transforms/ObjCARC.h"
 #include "llvm/Transforms/Utils/Local.h"
-#include "ARCInstKind.h"
 
 namespace llvm {
 class raw_ostream;
@@ -43,99 +44,6 @@ class raw_ostream;
 namespace llvm {
 namespace objcarc {
 
-/// \brief A handy option to enable/disable all ARC Optimizations.
-extern bool EnableARCOpts;
-
-/// \brief Test if the given module looks interesting to run ARC optimization
-/// on.
-static inline bool ModuleHasARC(const Module &M) {
-  return
-    M.getNamedValue("objc_retain") ||
-    M.getNamedValue("objc_release") ||
-    M.getNamedValue("objc_autorelease") ||
-    M.getNamedValue("objc_retainAutoreleasedReturnValue") ||
-    M.getNamedValue("objc_retainBlock") ||
-    M.getNamedValue("objc_autoreleaseReturnValue") ||
-    M.getNamedValue("objc_autoreleasePoolPush") ||
-    M.getNamedValue("objc_loadWeakRetained") ||
-    M.getNamedValue("objc_loadWeak") ||
-    M.getNamedValue("objc_destroyWeak") ||
-    M.getNamedValue("objc_storeWeak") ||
-    M.getNamedValue("objc_initWeak") ||
-    M.getNamedValue("objc_moveWeak") ||
-    M.getNamedValue("objc_copyWeak") ||
-    M.getNamedValue("objc_retainedObject") ||
-    M.getNamedValue("objc_unretainedObject") ||
-    M.getNamedValue("objc_unretainedPointer") ||
-    M.getNamedValue("clang.arc.use");
-}
-
-/// \brief This is a wrapper around getUnderlyingObject which also knows how to
-/// look through objc_retain and objc_autorelease calls, which we know to return
-/// their argument verbatim.
-static inline const Value *GetUnderlyingObjCPtr(const Value *V,
-                                                const DataLayout &DL) {
-  for (;;) {
-    V = GetUnderlyingObject(V, DL);
-    if (!IsForwarding(GetBasicARCInstKind(V)))
-      break;
-    V = cast<CallInst>(V)->getArgOperand(0);
-  }
-
-  return V;
-}
-
-/// The RCIdentity root of a value \p V is a dominating value U for which
-/// retaining or releasing U is equivalent to retaining or releasing V. In other
-/// words, ARC operations on \p V are equivalent to ARC operations on \p U.
-///
-/// We use this in the ARC optimizer to make it easier to match up ARC
-/// operations by always mapping ARC operations to RCIdentityRoots instead of
-/// pointers themselves.
-///
-/// The two ways that we see RCIdentical values in ObjC are via:
-///
-///   1. PointerCasts
-///   2. Forwarding Calls that return their argument verbatim.
-///
-/// Thus this function strips off pointer casts and forwarding calls. *NOTE*
-/// This implies that two RCIdentical values must alias.
-static inline const Value *GetRCIdentityRoot(const Value *V) {
-  for (;;) {
-    V = V->stripPointerCasts();
-    if (!IsForwarding(GetBasicARCInstKind(V)))
-      break;
-    V = cast<CallInst>(V)->getArgOperand(0);
-  }
-  return V;
-}
-
-/// Helper which calls const Value *GetRCIdentityRoot(const Value *V) and just
-/// casts away the const of the result. For documentation about what an
-/// RCIdentityRoot (and by extension GetRCIdentityRoot is) look at that
-/// function.
-static inline Value *GetRCIdentityRoot(Value *V) {
-  return const_cast<Value *>(GetRCIdentityRoot((const Value *)V));
-}
-
-/// \brief Assuming the given instruction is one of the special calls such as
-/// objc_retain or objc_release, return the RCIdentity root of the argument of
-/// the call.
-static inline Value *GetArgRCIdentityRoot(Value *Inst) {
-  return GetRCIdentityRoot(cast<CallInst>(Inst)->getArgOperand(0));
-}
-
-static inline bool IsNullOrUndef(const Value *V) {
-  return isa<ConstantPointerNull>(V) || isa<UndefValue>(V);
-}
-
-static inline bool IsNoopInstruction(const Instruction *I) {
-  return isa<BitCastInst>(I) ||
-    (isa<GetElementPtrInst>(I) &&
-     cast<GetElementPtrInst>(I)->hasAllZeroIndices());
-}
-
-
 /// \brief Erase the given instruction.
 ///
 /// Many ObjC calls return their argument verbatim,
@@ -162,152 +70,6 @@ static inline void EraseInstruction(Instruction *CI) {
     RecursivelyDeleteTriviallyDeadInstructions(OldArg);
 }
 
-/// \brief Test whether the given value is possible a retainable object pointer.
-static inline bool IsPotentialRetainableObjPtr(const Value *Op) {
-  // Pointers to static or stack storage are not valid retainable object
-  // pointers.
-  if (isa<Constant>(Op) || isa<AllocaInst>(Op))
-    return false;
-  // Special arguments can not be a valid retainable object pointer.
-  if (const Argument *Arg = dyn_cast<Argument>(Op))
-    if (Arg->hasByValAttr() ||
-        Arg->hasInAllocaAttr() ||
-        Arg->hasNestAttr() ||
-        Arg->hasStructRetAttr())
-      return false;
-  // Only consider values with pointer types.
-  //
-  // It seemes intuitive to exclude function pointer types as well, since
-  // functions are never retainable object pointers, however clang occasionally
-  // bitcasts retainable object pointers to function-pointer type temporarily.
-  PointerType *Ty = dyn_cast<PointerType>(Op->getType());
-  if (!Ty)
-    return false;
-  // Conservatively assume anything else is a potential retainable object
-  // pointer.
-  return true;
-}
-
-static inline bool IsPotentialRetainableObjPtr(const Value *Op,
-                                               AliasAnalysis &AA) {
-  // First make the rudimentary check.
-  if (!IsPotentialRetainableObjPtr(Op))
-    return false;
-
-  // Objects in constant memory are not reference-counted.
-  if (AA.pointsToConstantMemory(Op))
-    return false;
-
-  // Pointers in constant memory are not pointing to reference-counted objects.
-  if (const LoadInst *LI = dyn_cast<LoadInst>(Op))
-    if (AA.pointsToConstantMemory(LI->getPointerOperand()))
-      return false;
-
-  // Otherwise assume the worst.
-  return true;
-}
-
-/// \brief Helper for GetARCInstKind. Determines what kind of construct CS
-/// is.
-static inline ARCInstKind GetCallSiteClass(ImmutableCallSite CS) {
-  for (ImmutableCallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
-       I != E; ++I)
-    if (IsPotentialRetainableObjPtr(*I))
-      return CS.onlyReadsMemory() ? ARCInstKind::User : ARCInstKind::CallOrUser;
-
-  return CS.onlyReadsMemory() ? ARCInstKind::None : ARCInstKind::Call;
-}
-
-/// \brief Return true if this value refers to a distinct and identifiable
-/// object.
-///
-/// This is similar to AliasAnalysis's isIdentifiedObject, except that it uses
-/// special knowledge of ObjC conventions.
-static inline bool IsObjCIdentifiedObject(const Value *V) {
-  // Assume that call results and arguments have their own "provenance".
-  // Constants (including GlobalVariables) and Allocas are never
-  // reference-counted.
-  if (isa<CallInst>(V) || isa<InvokeInst>(V) ||
-      isa<Argument>(V) || isa<Constant>(V) ||
-      isa<AllocaInst>(V))
-    return true;
-
-  if (const LoadInst *LI = dyn_cast<LoadInst>(V)) {
-    const Value *Pointer =
-      GetRCIdentityRoot(LI->getPointerOperand());
-    if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(Pointer)) {
-      // A constant pointer can't be pointing to an object on the heap. It may
-      // be reference-counted, but it won't be deleted.
-      if (GV->isConstant())
-        return true;
-      StringRef Name = GV->getName();
-      // These special variables are known to hold values which are not
-      // reference-counted pointers.
-      if (Name.startswith("\01l_objc_msgSend_fixup_"))
-        return true;
-
-      StringRef Section = GV->getSection();
-      if (Section.find("__message_refs") != StringRef::npos ||
-          Section.find("__objc_classrefs") != StringRef::npos ||
-          Section.find("__objc_superrefs") != StringRef::npos ||
-          Section.find("__objc_methname") != StringRef::npos ||
-          Section.find("__cstring") != StringRef::npos)
-        return true;
-    }
-  }
-
-  return false;
-}
-
-enum class ARCMDKindID {
-  ImpreciseRelease,
-  CopyOnEscape,
-  NoObjCARCExceptions,
-};
-
-/// A cache of MDKinds used by various ARC optimizations.
-class ARCMDKindCache {
-  Module *M;
-
-  /// The Metadata Kind for clang.imprecise_release metadata.
-  llvm::Optional<unsigned> ImpreciseReleaseMDKind;
-
-  /// The Metadata Kind for clang.arc.copy_on_escape metadata.
-  llvm::Optional<unsigned> CopyOnEscapeMDKind;
-
-  /// The Metadata Kind for clang.arc.no_objc_arc_exceptions metadata.
-  llvm::Optional<unsigned> NoObjCARCExceptionsMDKind;
-
-public:
-  void init(Module *Mod) {
-    M = Mod;
-    ImpreciseReleaseMDKind = NoneType::None;
-    CopyOnEscapeMDKind = NoneType::None;
-    NoObjCARCExceptionsMDKind = NoneType::None;
-  }
-
-  unsigned get(ARCMDKindID ID) {
-    switch (ID) {
-    case ARCMDKindID::ImpreciseRelease:
-      if (!ImpreciseReleaseMDKind)
-        ImpreciseReleaseMDKind =
-            M->getContext().getMDKindID("clang.imprecise_release");
-      return *ImpreciseReleaseMDKind;
-    case ARCMDKindID::CopyOnEscape:
-      if (!CopyOnEscapeMDKind)
-        CopyOnEscapeMDKind =
-            M->getContext().getMDKindID("clang.arc.copy_on_escape");
-      return *CopyOnEscapeMDKind;
-    case ARCMDKindID::NoObjCARCExceptions:
-      if (!NoObjCARCExceptionsMDKind)
-        NoObjCARCExceptionsMDKind =
-            M->getContext().getMDKindID("clang.arc.no_objc_arc_exceptions");
-      return *NoObjCARCExceptionsMDKind;
-    }
-    llvm_unreachable("Covered switch isn't covered?!");
-  }
-};
-
 } // end namespace objcarc
 } // end namespace llvm
 

lib/Transforms/ObjCARC/ObjCARCOpts.cpp

@@ -28,7 +28,6 @@
 #include "ARCRuntimeEntryPoints.h"
 #include "BlotMapVector.h"
 #include "DependencyAnalysis.h"
-#include "ObjCARCAliasAnalysis.h"
 #include "ProvenanceAnalysis.h"
 #include "PtrState.h"
 #include "llvm/ADT/DenseMap.h"
@@ -36,6 +35,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/ObjCARCAliasAnalysis.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/LLVMContext.h"

lib/Transforms/ObjCARC/PtrState.h

@@ -17,8 +17,8 @@
 #ifndef LLVM_LIB_TRANSFORMS_OBJCARC_PTRSTATE_H
 #define LLVM_LIB_TRANSFORMS_OBJCARC_PTRSTATE_H
 
-#include "ARCInstKind.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Analysis/ObjCARCInstKind.h"
 #include "llvm/IR/Instruction.h"
 #include "llvm/IR/Value.h"
 #include "llvm/Support/raw_ostream.h"