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 CLANG_CODEGEN_CGCALL_H 16 #define CLANG_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: 59 struct Writeback { 60 /// The original argument. Note that the argument l-value 61 /// is potentially null. 62 LValue Source; 63 64 /// The temporary alloca. 65 llvm::Value *Temporary; 66 67 /// A value to "use" after the writeback, or null. 68 llvm::Value *ToUse; 69 }; 70 71 struct CallArgCleanup { 72 EHScopeStack::stable_iterator Cleanup; 73 74 /// The "is active" insertion point. This instruction is temporary and 75 /// will be removed after insertion. 76 llvm::Instruction *IsActiveIP; 77 }; 78 79 void add(RValue rvalue, QualType type, bool needscopy = false) { 80 push_back(CallArg(rvalue, type, needscopy)); 81 } 82 addFrom(const CallArgList & other)83 void addFrom(const CallArgList &other) { 84 insert(end(), other.begin(), other.end()); 85 Writebacks.insert(Writebacks.end(), 86 other.Writebacks.begin(), other.Writebacks.end()); 87 } 88 addWriteback(LValue srcLV,llvm::Value * temporary,llvm::Value * toUse)89 void addWriteback(LValue srcLV, llvm::Value *temporary, 90 llvm::Value *toUse) { 91 Writeback writeback; 92 writeback.Source = srcLV; 93 writeback.Temporary = temporary; 94 writeback.ToUse = toUse; 95 Writebacks.push_back(writeback); 96 } 97 hasWritebacks()98 bool hasWritebacks() const { return !Writebacks.empty(); } 99 100 typedef SmallVectorImpl<Writeback>::const_iterator writeback_iterator; writeback_begin()101 writeback_iterator writeback_begin() const { return Writebacks.begin(); } writeback_end()102 writeback_iterator writeback_end() const { return Writebacks.end(); } 103 addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,llvm::Instruction * IsActiveIP)104 void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup, 105 llvm::Instruction *IsActiveIP) { 106 CallArgCleanup ArgCleanup; 107 ArgCleanup.Cleanup = Cleanup; 108 ArgCleanup.IsActiveIP = IsActiveIP; 109 CleanupsToDeactivate.push_back(ArgCleanup); 110 } 111 getCleanupsToDeactivate()112 ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const { 113 return CleanupsToDeactivate; 114 } 115 116 private: 117 SmallVector<Writeback, 1> Writebacks; 118 119 /// Deactivate these cleanups immediately before making the call. This 120 /// is used to cleanup objects that are owned by the callee once the call 121 /// occurs. 122 SmallVector<CallArgCleanup, 1> CleanupsToDeactivate; 123 }; 124 125 /// A class for recording the number of arguments that a function 126 /// signature requires. 127 class RequiredArgs { 128 /// The number of required arguments, or ~0 if the signature does 129 /// not permit optional arguments. 130 unsigned NumRequired; 131 public: 132 enum All_t { All }; 133 RequiredArgs(All_t _)134 RequiredArgs(All_t _) : NumRequired(~0U) {} RequiredArgs(unsigned n)135 explicit RequiredArgs(unsigned n) : NumRequired(n) { 136 assert(n != ~0U); 137 } 138 139 /// Compute the arguments required by the given formal prototype, 140 /// given that there may be some additional, non-formal arguments 141 /// in play. forPrototypePlus(const FunctionProtoType * prototype,unsigned additional)142 static RequiredArgs forPrototypePlus(const FunctionProtoType *prototype, 143 unsigned additional) { 144 if (!prototype->isVariadic()) return All; 145 return RequiredArgs(prototype->getNumArgs() + additional); 146 } 147 forPrototype(const FunctionProtoType * prototype)148 static RequiredArgs forPrototype(const FunctionProtoType *prototype) { 149 return forPrototypePlus(prototype, 0); 150 } 151 forPrototype(CanQual<FunctionProtoType> prototype)152 static RequiredArgs forPrototype(CanQual<FunctionProtoType> prototype) { 153 return forPrototype(prototype.getTypePtr()); 154 } 155 forPrototypePlus(CanQual<FunctionProtoType> prototype,unsigned additional)156 static RequiredArgs forPrototypePlus(CanQual<FunctionProtoType> prototype, 157 unsigned additional) { 158 return forPrototypePlus(prototype.getTypePtr(), additional); 159 } 160 allowsOptionalArgs()161 bool allowsOptionalArgs() const { return NumRequired != ~0U; } getNumRequiredArgs()162 unsigned getNumRequiredArgs() const { 163 assert(allowsOptionalArgs()); 164 return NumRequired; 165 } 166 getOpaqueData()167 unsigned getOpaqueData() const { return NumRequired; } getFromOpaqueData(unsigned value)168 static RequiredArgs getFromOpaqueData(unsigned value) { 169 if (value == ~0U) return All; 170 return RequiredArgs(value); 171 } 172 }; 173 174 /// FunctionArgList - Type for representing both the decl and type 175 /// of parameters to a function. The decl must be either a 176 /// ParmVarDecl or ImplicitParamDecl. 177 class FunctionArgList : public SmallVector<const VarDecl*, 16> { 178 }; 179 180 /// CGFunctionInfo - Class to encapsulate the information about a 181 /// function definition. 182 class CGFunctionInfo : public llvm::FoldingSetNode { 183 struct ArgInfo { 184 CanQualType type; 185 ABIArgInfo info; 186 }; 187 188 /// The LLVM::CallingConv to use for this function (as specified by the 189 /// user). 190 unsigned CallingConvention : 8; 191 192 /// The LLVM::CallingConv to actually use for this function, which may 193 /// depend on the ABI. 194 unsigned EffectiveCallingConvention : 8; 195 196 /// The clang::CallingConv that this was originally created with. 197 unsigned ASTCallingConvention : 8; 198 199 /// Whether this function is noreturn. 200 unsigned NoReturn : 1; 201 202 /// Whether this function is returns-retained. 203 unsigned ReturnsRetained : 1; 204 205 /// How many arguments to pass inreg. 206 unsigned HasRegParm : 1; 207 unsigned RegParm : 4; 208 209 RequiredArgs Required; 210 211 unsigned NumArgs; getArgsBuffer()212 ArgInfo *getArgsBuffer() { 213 return reinterpret_cast<ArgInfo*>(this+1); 214 } getArgsBuffer()215 const ArgInfo *getArgsBuffer() const { 216 return reinterpret_cast<const ArgInfo*>(this + 1); 217 } 218 CGFunctionInfo()219 CGFunctionInfo() : Required(RequiredArgs::All) {} 220 221 public: 222 static CGFunctionInfo *create(unsigned llvmCC, 223 const FunctionType::ExtInfo &extInfo, 224 CanQualType resultType, 225 ArrayRef<CanQualType> argTypes, 226 RequiredArgs required); 227 228 typedef const ArgInfo *const_arg_iterator; 229 typedef ArgInfo *arg_iterator; 230 arg_begin()231 const_arg_iterator arg_begin() const { return getArgsBuffer() + 1; } arg_end()232 const_arg_iterator arg_end() const { return getArgsBuffer() + 1 + NumArgs; } arg_begin()233 arg_iterator arg_begin() { return getArgsBuffer() + 1; } arg_end()234 arg_iterator arg_end() { return getArgsBuffer() + 1 + NumArgs; } 235 arg_size()236 unsigned arg_size() const { return NumArgs; } 237 isVariadic()238 bool isVariadic() const { return Required.allowsOptionalArgs(); } getRequiredArgs()239 RequiredArgs getRequiredArgs() const { return Required; } 240 isNoReturn()241 bool isNoReturn() const { return NoReturn; } 242 243 /// In ARC, whether this function retains its return value. This 244 /// is not always reliable for call sites. isReturnsRetained()245 bool isReturnsRetained() const { return ReturnsRetained; } 246 247 /// getASTCallingConvention() - Return the AST-specified calling 248 /// convention. getASTCallingConvention()249 CallingConv getASTCallingConvention() const { 250 return CallingConv(ASTCallingConvention); 251 } 252 253 /// getCallingConvention - Return the user specified calling 254 /// convention, which has been translated into an LLVM CC. getCallingConvention()255 unsigned getCallingConvention() const { return CallingConvention; } 256 257 /// getEffectiveCallingConvention - Return the actual calling convention to 258 /// use, which may depend on the ABI. getEffectiveCallingConvention()259 unsigned getEffectiveCallingConvention() const { 260 return EffectiveCallingConvention; 261 } setEffectiveCallingConvention(unsigned Value)262 void setEffectiveCallingConvention(unsigned Value) { 263 EffectiveCallingConvention = Value; 264 } 265 getHasRegParm()266 bool getHasRegParm() const { return HasRegParm; } getRegParm()267 unsigned getRegParm() const { return RegParm; } 268 getExtInfo()269 FunctionType::ExtInfo getExtInfo() const { 270 return FunctionType::ExtInfo(isNoReturn(), 271 getHasRegParm(), getRegParm(), 272 getASTCallingConvention(), 273 isReturnsRetained()); 274 } 275 getReturnType()276 CanQualType getReturnType() const { return getArgsBuffer()[0].type; } 277 getReturnInfo()278 ABIArgInfo &getReturnInfo() { return getArgsBuffer()[0].info; } getReturnInfo()279 const ABIArgInfo &getReturnInfo() const { return getArgsBuffer()[0].info; } 280 Profile(llvm::FoldingSetNodeID & ID)281 void Profile(llvm::FoldingSetNodeID &ID) { 282 ID.AddInteger(getASTCallingConvention()); 283 ID.AddBoolean(NoReturn); 284 ID.AddBoolean(ReturnsRetained); 285 ID.AddBoolean(HasRegParm); 286 ID.AddInteger(RegParm); 287 ID.AddInteger(Required.getOpaqueData()); 288 getReturnType().Profile(ID); 289 for (arg_iterator it = arg_begin(), ie = arg_end(); it != ie; ++it) 290 it->type.Profile(ID); 291 } Profile(llvm::FoldingSetNodeID & ID,const FunctionType::ExtInfo & info,RequiredArgs required,CanQualType resultType,ArrayRef<CanQualType> argTypes)292 static void Profile(llvm::FoldingSetNodeID &ID, 293 const FunctionType::ExtInfo &info, 294 RequiredArgs required, 295 CanQualType resultType, 296 ArrayRef<CanQualType> argTypes) { 297 ID.AddInteger(info.getCC()); 298 ID.AddBoolean(info.getNoReturn()); 299 ID.AddBoolean(info.getProducesResult()); 300 ID.AddBoolean(info.getHasRegParm()); 301 ID.AddInteger(info.getRegParm()); 302 ID.AddInteger(required.getOpaqueData()); 303 resultType.Profile(ID); 304 for (ArrayRef<CanQualType>::iterator 305 i = argTypes.begin(), e = argTypes.end(); i != e; ++i) { 306 i->Profile(ID); 307 } 308 } 309 }; 310 311 /// ReturnValueSlot - Contains the address where the return value of a 312 /// function can be stored, and whether the address is volatile or not. 313 class ReturnValueSlot { 314 llvm::PointerIntPair<llvm::Value *, 1, bool> Value; 315 316 public: ReturnValueSlot()317 ReturnValueSlot() {} ReturnValueSlot(llvm::Value * Value,bool IsVolatile)318 ReturnValueSlot(llvm::Value *Value, bool IsVolatile) 319 : Value(Value, IsVolatile) {} 320 isNull()321 bool isNull() const { return !getValue(); } 322 isVolatile()323 bool isVolatile() const { return Value.getInt(); } getValue()324 llvm::Value *getValue() const { return Value.getPointer(); } 325 }; 326 327 } // end namespace CodeGen 328 } // end namespace clang 329 330 #endif 331