lib/Transforms/ObjCARC/ARCRuntimeEntryPoints.h

   1 //===- ARCRuntimeEntryPoints.h - ObjC ARC Optimization --*- C++ -*---------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 /// \file
  10 /// This file contains a class ARCRuntimeEntryPoints for use in
  11 /// creating/managing references to entry points to the arc objective c runtime.
  12 ///
  13 /// WARNING: This file knows about certain library functions. It recognizes them
  14 /// by name, and hardwires knowledge of their semantics.
  15 ///
  16 /// WARNING: This file knows about how certain Objective-C library functions are
  17 /// used. Naive LLVM IR transformations which would otherwise be
  18 /// behavior-preserving may break these assumptions.
  19 ///
  20 //===----------------------------------------------------------------------===//
  21
  22 #ifndef LLVM_LIB_TRANSFORMS_OBJCARC_ARCRUNTIMEENTRYPOINTS_H
  23 #define LLVM_LIB_TRANSFORMS_OBJCARC_ARCRUNTIMEENTRYPOINTS_H
  24
  25 #include "ObjCARC.h"
  26
  27 namespace llvm {
  28 namespace objcarc {
  29
  30 enum class ARCRuntimeEntryPointKind {
  31   AutoreleaseRV,
  32   Release,
  33   Retain,
  34   RetainBlock,
  35   Autorelease,
  36   StoreStrong,
  37   RetainRV,
  38   RetainAutorelease,
  39   RetainAutoreleaseRV,
  40 };
  41
  42 /// Declarations for ObjC runtime functions and constants. These are initialized
  43 /// lazily to avoid cluttering up the Module with unused declarations.
  44 class ARCRuntimeEntryPoints {
  45 public:
  46   ARCRuntimeEntryPoints() : TheModule(nullptr),
  47                             AutoreleaseRV(nullptr),
  48                             Release(nullptr),
  49                             Retain(nullptr),
  50                             RetainBlock(nullptr),
  51                             Autorelease(nullptr),
  52                             StoreStrong(nullptr),
  53                             RetainRV(nullptr),
  54                             RetainAutorelease(nullptr),
  55                             RetainAutoreleaseRV(nullptr) { }
  56
  57   void init(Module *M) {
  58     TheModule = M;
  59     AutoreleaseRV = nullptr;
  60     Release = nullptr;
  61     Retain = nullptr;
  62     RetainBlock = nullptr;
  63     Autorelease = nullptr;
  64     StoreStrong = nullptr;
  65     RetainRV = nullptr;
  66     RetainAutorelease = nullptr;
  67     RetainAutoreleaseRV = nullptr;
  68   }
  69
  70   Constant *get(ARCRuntimeEntryPointKind kind) {
  71     assert(TheModule != nullptr && "Not initialized.");
  72
  73     switch (kind) {
  74     case ARCRuntimeEntryPointKind::AutoreleaseRV:
  75       return getI8XRetI8XEntryPoint(AutoreleaseRV,
  76                                     "objc_autoreleaseReturnValue", true);
  77     case ARCRuntimeEntryPointKind::Release:
  78       return getVoidRetI8XEntryPoint(Release, "objc_release");
  79     case ARCRuntimeEntryPointKind::Retain:
  80       return getI8XRetI8XEntryPoint(Retain, "objc_retain", true);
  81     case ARCRuntimeEntryPointKind::RetainBlock:
  82       return getI8XRetI8XEntryPoint(RetainBlock, "objc_retainBlock", false);
  83     case ARCRuntimeEntryPointKind::Autorelease:
  84       return getI8XRetI8XEntryPoint(Autorelease, "objc_autorelease", true);
  85     case ARCRuntimeEntryPointKind::StoreStrong:
  86       return getI8XRetI8XXI8XEntryPoint(StoreStrong, "objc_storeStrong");
  87     case ARCRuntimeEntryPointKind::RetainRV:
  88       return getI8XRetI8XEntryPoint(RetainRV,
  89                                     "objc_retainAutoreleasedReturnValue", true);
  90     case ARCRuntimeEntryPointKind::RetainAutorelease:
  91       return getI8XRetI8XEntryPoint(RetainAutorelease, "objc_retainAutorelease",
  92                                     true);
  93     case ARCRuntimeEntryPointKind::RetainAutoreleaseRV:
  94       return getI8XRetI8XEntryPoint(RetainAutoreleaseRV,
  95                                     "objc_retainAutoreleaseReturnValue", true);
  96     }
  97
  98     llvm_unreachable("Switch should be a covered switch.");
  99   }
 100
 101 private:
 102   /// Cached reference to the module which we will insert declarations into.
 103   Module *TheModule;
 104
 105   /// Declaration for ObjC runtime function objc_autoreleaseReturnValue.
 106   Constant *AutoreleaseRV;
 107   /// Declaration for ObjC runtime function objc_release.
 108   Constant *Release;
 109   /// Declaration for ObjC runtime function objc_retain.
 110   Constant *Retain;
 111   /// Declaration for ObjC runtime function objc_retainBlock.
 112   Constant *RetainBlock;
 113   /// Declaration for ObjC runtime function objc_autorelease.
 114   Constant *Autorelease;
 115   /// Declaration for objc_storeStrong().
 116   Constant *StoreStrong;
 117   /// Declaration for objc_retainAutoreleasedReturnValue().
 118   Constant *RetainRV;
 119   /// Declaration for objc_retainAutorelease().
 120   Constant *RetainAutorelease;
 121   /// Declaration for objc_retainAutoreleaseReturnValue().
 122   Constant *RetainAutoreleaseRV;
 123
 124   Constant *getVoidRetI8XEntryPoint(Constant *&Decl, StringRef Name) {
 125     if (Decl)
 126       return Decl;
 127
 128     LLVMContext &C = TheModule->getContext();
 129     Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
 130     AttributeList Attr = AttributeList().addAttribute(
 131         C, AttributeList::FunctionIndex, Attribute::NoUnwind);
 132     FunctionType *Fty = FunctionType::get(Type::getVoidTy(C), Params,
 133                                           /*isVarArg=*/false);
 134     return Decl = TheModule->getOrInsertFunction(Name, Fty, Attr);
 135   }
 136
 137   Constant *getI8XRetI8XEntryPoint(Constant *&Decl, StringRef Name,
 138                                    bool NoUnwind = false) {
 139     if (Decl)
 140       return Decl;
 141
 142     LLVMContext &C = TheModule->getContext();
 143     Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
 144     Type *Params[] = { I8X };
 145     FunctionType *Fty = FunctionType::get(I8X, Params, /*isVarArg=*/false);
 146     AttributeList Attr = AttributeList();
 147
 148     if (NoUnwind)
 149       Attr = Attr.addAttribute(C, AttributeList::FunctionIndex,
 150                                Attribute::NoUnwind);
 151
 152     return Decl = TheModule->getOrInsertFunction(Name, Fty, Attr);
 153   }
 154
 155   Constant *getI8XRetI8XXI8XEntryPoint(Constant *&Decl, StringRef Name) {
 156     if (Decl)
 157       return Decl;
 158
 159     LLVMContext &C = TheModule->getContext();
 160     Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
 161     Type *I8XX = PointerType::getUnqual(I8X);
 162     Type *Params[] = { I8XX, I8X };
 163
 164     AttributeList Attr = AttributeList().addAttribute(
 165         C, AttributeList::FunctionIndex, Attribute::NoUnwind);
 166     Attr = Attr.addParamAttribute(C, 0, Attribute::NoCapture);
 167
 168     FunctionType *Fty = FunctionType::get(Type::getVoidTy(C), Params,
 169                                           /*isVarArg=*/false);
 170
 171     return Decl = TheModule->getOrInsertFunction(Name, Fty, Attr);
 172   }
 173
 174 }; // class ARCRuntimeEntryPoints
 175
 176 } // namespace objcarc
 177 } // namespace llvm
 178
 179 #endif