1 //===----- CGCall.h - Encapsulate calling convention details ----*- 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 // 10 // These classes wrap the information about a call or function 11 // definition used to handle ABI compliancy. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CLANG_LIB_CODEGEN_CGCALL_H 16 #define LLVM_CLANG_LIB_CODEGEN_CGCALL_H 17 18 #include "CGValue.h" 19 #include "EHScopeStack.h" 20 #include "clang/AST/CanonicalType.h" 21 #include "clang/AST/Type.h" 22 #include "llvm/ADT/FoldingSet.h" 23 #include "llvm/IR/Value.h" 24 25 // FIXME: Restructure so we don't have to expose so much stuff. 26 #include "ABIInfo.h" 27 28 namespace llvm { 29 class AttributeSet; 30 class Function; 31 class Type; 32 class Value; 33 } 34 35 namespace clang { 36 class ASTContext; 37 class Decl; 38 class FunctionDecl; 39 class ObjCMethodDecl; 40 class VarDecl; 41 42 namespace CodeGen { 43 typedef SmallVector<llvm::AttributeSet, 8> AttributeListType; 44 45 struct CallArg { 46 RValue RV; 47 QualType Ty; 48 bool NeedsCopy; CallArgCallArg49 CallArg(RValue rv, QualType ty, bool needscopy) 50 : RV(rv), Ty(ty), NeedsCopy(needscopy) 51 { } 52 }; 53 54 /// CallArgList - Type for representing both the value and type of 55 /// arguments in a call. 56 class CallArgList : 57 public SmallVector<CallArg, 16> { 58 public: CallArgList()59 CallArgList() : StackBase(nullptr) {} 60 61 struct Writeback { 62 /// The original argument. Note that the argument l-value 63 /// is potentially null. 64 LValue Source; 65 66 /// The temporary alloca. 67 Address Temporary; 68 69 /// A value to "use" after the writeback, or null. 70 llvm::Value *ToUse; 71 }; 72 73 struct CallArgCleanup { 74 EHScopeStack::stable_iterator Cleanup; 75 76 /// The "is active" insertion point. This instruction is temporary and 77 /// will be removed after insertion. 78 llvm::Instruction *IsActiveIP; 79 }; 80 81 void add(RValue rvalue, QualType type, bool needscopy = false) { 82 push_back(CallArg(rvalue, type, needscopy)); 83 } 84 addFrom(const CallArgList & other)85 void addFrom(const CallArgList &other) { 86 insert(end(), other.begin(), other.end()); 87 Writebacks.insert(Writebacks.end(), 88 other.Writebacks.begin(), other.Writebacks.end()); 89 } 90 addWriteback(LValue srcLV,Address temporary,llvm::Value * toUse)91 void addWriteback(LValue srcLV, Address temporary, 92 llvm::Value *toUse) { 93 Writeback writeback = { srcLV, temporary, toUse }; 94 Writebacks.push_back(writeback); 95 } 96 hasWritebacks()97 bool hasWritebacks() const { return !Writebacks.empty(); } 98 99 typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator> 100 writeback_const_range; 101 writebacks()102 writeback_const_range writebacks() const { 103 return writeback_const_range(Writebacks.begin(), Writebacks.end()); 104 } 105 addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,llvm::Instruction * IsActiveIP)106 void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup, 107 llvm::Instruction *IsActiveIP) { 108 CallArgCleanup ArgCleanup; 109 ArgCleanup.Cleanup = Cleanup; 110 ArgCleanup.IsActiveIP = IsActiveIP; 111 CleanupsToDeactivate.push_back(ArgCleanup); 112 } 113 getCleanupsToDeactivate()114 ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const { 115 return CleanupsToDeactivate; 116 } 117 118 void allocateArgumentMemory(CodeGenFunction &CGF); getStackBase()119 llvm::Instruction *getStackBase() const { return StackBase; } 120 void freeArgumentMemory(CodeGenFunction &CGF) const; 121 122 /// \brief Returns if we're using an inalloca struct to pass arguments in 123 /// memory. isUsingInAlloca()124 bool isUsingInAlloca() const { return StackBase; } 125 126 private: 127 SmallVector<Writeback, 1> Writebacks; 128 129 /// Deactivate these cleanups immediately before making the call. This 130 /// is used to cleanup objects that are owned by the callee once the call 131 /// occurs. 132 SmallVector<CallArgCleanup, 1> CleanupsToDeactivate; 133 134 /// The stacksave call. It dominates all of the argument evaluation. 135 llvm::CallInst *StackBase; 136 137 /// The iterator pointing to the stack restore cleanup. We manually run and 138 /// deactivate this cleanup after the call in the unexceptional case because 139 /// it doesn't run in the normal order. 140 EHScopeStack::stable_iterator StackCleanup; 141 }; 142 143 /// FunctionArgList - Type for representing both the decl and type 144 /// of parameters to a function. The decl must be either a 145 /// ParmVarDecl or ImplicitParamDecl. 146 class FunctionArgList : public SmallVector<const VarDecl*, 16> { 147 }; 148 149 /// ReturnValueSlot - Contains the address where the return value of a 150 /// function can be stored, and whether the address is volatile or not. 151 class ReturnValueSlot { 152 llvm::PointerIntPair<llvm::Value *, 2, unsigned int> Value; 153 CharUnits Alignment; 154 155 // Return value slot flags 156 enum Flags { 157 IS_VOLATILE = 0x1, 158 IS_UNUSED = 0x2, 159 }; 160 161 public: ReturnValueSlot()162 ReturnValueSlot() {} 163 ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false) 164 : Value(Addr.isValid() ? Addr.getPointer() : nullptr, 165 (IsVolatile ? IS_VOLATILE : 0) | (IsUnused ? IS_UNUSED : 0)), 166 Alignment(Addr.isValid() ? Addr.getAlignment() : CharUnits::Zero()) {} 167 isNull()168 bool isNull() const { return !getValue().isValid(); } 169 isVolatile()170 bool isVolatile() const { return Value.getInt() & IS_VOLATILE; } getValue()171 Address getValue() const { return Address(Value.getPointer(), Alignment); } isUnused()172 bool isUnused() const { return Value.getInt() & IS_UNUSED; } 173 }; 174 175 } // end namespace CodeGen 176 } // end namespace clang 177 178 #endif 179