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14 | pmbaty | 1 | //===-------- llvm/GlobalIFunc.h - GlobalIFunc class ------------*- C++ -*-===// |
2 | // |
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3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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4 | // See https://llvm.org/LICENSE.txt for license information. |
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5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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6 | // |
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7 | //===----------------------------------------------------------------------===// |
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8 | /// |
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9 | /// \file |
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10 | /// This file contains the declaration of the GlobalIFunc class, which |
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11 | /// represents a single indirect function in the IR. Indirect function uses |
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12 | /// ELF symbol type extension to mark that the address of a declaration should |
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13 | /// be resolved at runtime by calling a resolver function. |
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14 | /// |
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15 | //===----------------------------------------------------------------------===// |
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16 | |||
17 | #ifndef LLVM_IR_GLOBALIFUNC_H |
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18 | #define LLVM_IR_GLOBALIFUNC_H |
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19 | |||
20 | #include "llvm/ADT/ilist_node.h" |
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21 | #include "llvm/IR/Constant.h" |
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22 | #include "llvm/IR/GlobalObject.h" |
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23 | #include "llvm/IR/OperandTraits.h" |
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24 | #include "llvm/IR/Value.h" |
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25 | |||
26 | namespace llvm { |
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27 | |||
28 | class Twine; |
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29 | class Module; |
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30 | |||
31 | // Traits class for using GlobalIFunc in symbol table in Module. |
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32 | template <typename ValueSubClass> class SymbolTableListTraits; |
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33 | |||
34 | class GlobalIFunc final : public GlobalObject, public ilist_node<GlobalIFunc> { |
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35 | friend class SymbolTableListTraits<GlobalIFunc>; |
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36 | |||
37 | GlobalIFunc(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage, |
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38 | const Twine &Name, Constant *Resolver, Module *Parent); |
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39 | |||
40 | public: |
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41 | GlobalIFunc(const GlobalIFunc &) = delete; |
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42 | GlobalIFunc &operator=(const GlobalIFunc &) = delete; |
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43 | |||
44 | /// If a parent module is specified, the ifunc is automatically inserted into |
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45 | /// the end of the specified module's ifunc list. |
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46 | static GlobalIFunc *create(Type *Ty, unsigned AddressSpace, |
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47 | LinkageTypes Linkage, const Twine &Name, |
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48 | Constant *Resolver, Module *Parent); |
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49 | |||
50 | // allocate space for exactly one operand |
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51 | void *operator new(size_t S) { return User::operator new(S, 1); } |
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52 | void operator delete(void *Ptr) { User::operator delete(Ptr); } |
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53 | |||
54 | /// Provide fast operand accessors |
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55 | DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant); |
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56 | |||
57 | void copyAttributesFrom(const GlobalIFunc *Src) { |
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58 | GlobalObject::copyAttributesFrom(Src); |
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59 | } |
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60 | |||
61 | /// This method unlinks 'this' from the containing module, but does not |
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62 | /// delete it. |
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63 | void removeFromParent(); |
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64 | |||
65 | /// This method unlinks 'this' from the containing module and deletes it. |
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66 | void eraseFromParent(); |
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67 | |||
68 | /// These methods retrieve and set ifunc resolver function. |
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69 | void setResolver(Constant *Resolver) { Op<0>().set(Resolver); } |
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70 | const Constant *getResolver() const { |
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71 | return static_cast<Constant *>(Op<0>().get()); |
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72 | } |
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73 | Constant *getResolver() { return static_cast<Constant *>(Op<0>().get()); } |
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74 | |||
75 | // Return the resolver function after peeling off potential ConstantExpr |
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76 | // indirection. |
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77 | const Function *getResolverFunction() const; |
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78 | Function *getResolverFunction() { |
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79 | return const_cast<Function *>( |
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80 | static_cast<const GlobalIFunc *>(this)->getResolverFunction()); |
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81 | } |
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82 | |||
83 | static FunctionType *getResolverFunctionType(Type *IFuncValTy) { |
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84 | return FunctionType::get(IFuncValTy->getPointerTo(), false); |
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85 | } |
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86 | |||
87 | static bool isValidLinkage(LinkageTypes L) { |
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88 | return isExternalLinkage(L) || isLocalLinkage(L) || isWeakLinkage(L) || |
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89 | isLinkOnceLinkage(L); |
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90 | } |
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91 | |||
92 | // Methods for support type inquiry through isa, cast, and dyn_cast: |
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93 | static bool classof(const Value *V) { |
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94 | return V->getValueID() == Value::GlobalIFuncVal; |
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95 | } |
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96 | |||
97 | // Apply specific operation to all resolver-related values. If resolver target |
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98 | // is already a global object, then apply the operation to it directly. If |
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99 | // target is a GlobalExpr or a GlobalAlias, evaluate it to its base object and |
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100 | // apply the operation for the base object and all aliases along the path. |
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101 | void applyAlongResolverPath(function_ref<void(const GlobalValue &)> Op) const; |
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102 | }; |
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103 | |||
104 | template <> |
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105 | struct OperandTraits<GlobalIFunc> |
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106 | : public FixedNumOperandTraits<GlobalIFunc, 1> {}; |
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107 | |||
108 | DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GlobalIFunc, Constant) |
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109 | |||
110 | } // end namespace llvm |
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111 | |||
112 | #endif // LLVM_IR_GLOBALIFUNC_H |