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/GlobalDecl.h" 22 #include "clang/AST/Type.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 AttributeList; 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 44 /// Abstract information about a function or function prototype. 45 class CGCalleeInfo { 46 /// The function prototype of the callee. 47 const FunctionProtoType *CalleeProtoTy; 48 /// The function declaration of the callee. 49 const Decl *CalleeDecl; 50 51 public: CGCalleeInfo()52 explicit CGCalleeInfo() : CalleeProtoTy(nullptr), CalleeDecl(nullptr) {} CGCalleeInfo(const FunctionProtoType * calleeProtoTy,const Decl * calleeDecl)53 CGCalleeInfo(const FunctionProtoType *calleeProtoTy, const Decl *calleeDecl) 54 : CalleeProtoTy(calleeProtoTy), CalleeDecl(calleeDecl) {} CGCalleeInfo(const FunctionProtoType * calleeProtoTy)55 CGCalleeInfo(const FunctionProtoType *calleeProtoTy) 56 : CalleeProtoTy(calleeProtoTy), CalleeDecl(nullptr) {} CGCalleeInfo(const Decl * calleeDecl)57 CGCalleeInfo(const Decl *calleeDecl) 58 : CalleeProtoTy(nullptr), CalleeDecl(calleeDecl) {} 59 getCalleeFunctionProtoType()60 const FunctionProtoType *getCalleeFunctionProtoType() const { 61 return CalleeProtoTy; 62 } getCalleeDecl()63 const Decl *getCalleeDecl() const { return CalleeDecl; } 64 }; 65 66 /// All available information about a concrete callee. 67 class CGCallee { 68 enum class SpecialKind : uintptr_t { 69 Invalid, 70 Builtin, 71 PseudoDestructor, 72 Virtual, 73 74 Last = Virtual 75 }; 76 77 struct BuiltinInfoStorage { 78 const FunctionDecl *Decl; 79 unsigned ID; 80 }; 81 struct PseudoDestructorInfoStorage { 82 const CXXPseudoDestructorExpr *Expr; 83 }; 84 struct VirtualInfoStorage { 85 const CallExpr *CE; 86 GlobalDecl MD; 87 Address Addr; 88 llvm::FunctionType *FTy; 89 }; 90 91 SpecialKind KindOrFunctionPointer; 92 union { 93 CGCalleeInfo AbstractInfo; 94 BuiltinInfoStorage BuiltinInfo; 95 PseudoDestructorInfoStorage PseudoDestructorInfo; 96 VirtualInfoStorage VirtualInfo; 97 }; 98 CGCallee(SpecialKind kind)99 explicit CGCallee(SpecialKind kind) : KindOrFunctionPointer(kind) {} 100 CGCallee(const FunctionDecl * builtinDecl,unsigned builtinID)101 CGCallee(const FunctionDecl *builtinDecl, unsigned builtinID) 102 : KindOrFunctionPointer(SpecialKind::Builtin) { 103 BuiltinInfo.Decl = builtinDecl; 104 BuiltinInfo.ID = builtinID; 105 } 106 107 public: CGCallee()108 CGCallee() : KindOrFunctionPointer(SpecialKind::Invalid) {} 109 110 /// Construct a callee. Call this constructor directly when this 111 /// isn't a direct call. CGCallee(const CGCalleeInfo & abstractInfo,llvm::Value * functionPtr)112 CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr) 113 : KindOrFunctionPointer(SpecialKind(uintptr_t(functionPtr))) { 114 AbstractInfo = abstractInfo; 115 assert(functionPtr && "configuring callee without function pointer"); 116 assert(functionPtr->getType()->isPointerTy()); 117 assert(functionPtr->getType()->getPointerElementType()->isFunctionTy()); 118 } 119 forBuiltin(unsigned builtinID,const FunctionDecl * builtinDecl)120 static CGCallee forBuiltin(unsigned builtinID, 121 const FunctionDecl *builtinDecl) { 122 CGCallee result(SpecialKind::Builtin); 123 result.BuiltinInfo.Decl = builtinDecl; 124 result.BuiltinInfo.ID = builtinID; 125 return result; 126 } 127 forPseudoDestructor(const CXXPseudoDestructorExpr * E)128 static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E) { 129 CGCallee result(SpecialKind::PseudoDestructor); 130 result.PseudoDestructorInfo.Expr = E; 131 return result; 132 } 133 134 static CGCallee forDirect(llvm::Constant *functionPtr, 135 const CGCalleeInfo &abstractInfo = CGCalleeInfo()) { 136 return CGCallee(abstractInfo, functionPtr); 137 } 138 forVirtual(const CallExpr * CE,GlobalDecl MD,Address Addr,llvm::FunctionType * FTy)139 static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr, 140 llvm::FunctionType *FTy) { 141 CGCallee result(SpecialKind::Virtual); 142 result.VirtualInfo.CE = CE; 143 result.VirtualInfo.MD = MD; 144 result.VirtualInfo.Addr = Addr; 145 result.VirtualInfo.FTy = FTy; 146 return result; 147 } 148 isBuiltin()149 bool isBuiltin() const { 150 return KindOrFunctionPointer == SpecialKind::Builtin; 151 } getBuiltinDecl()152 const FunctionDecl *getBuiltinDecl() const { 153 assert(isBuiltin()); 154 return BuiltinInfo.Decl; 155 } getBuiltinID()156 unsigned getBuiltinID() const { 157 assert(isBuiltin()); 158 return BuiltinInfo.ID; 159 } 160 isPseudoDestructor()161 bool isPseudoDestructor() const { 162 return KindOrFunctionPointer == SpecialKind::PseudoDestructor; 163 } getPseudoDestructorExpr()164 const CXXPseudoDestructorExpr *getPseudoDestructorExpr() const { 165 assert(isPseudoDestructor()); 166 return PseudoDestructorInfo.Expr; 167 } 168 isOrdinary()169 bool isOrdinary() const { 170 return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last); 171 } getAbstractInfo()172 CGCalleeInfo getAbstractInfo() const { 173 if (isVirtual()) 174 return VirtualInfo.MD.getDecl(); 175 assert(isOrdinary()); 176 return AbstractInfo; 177 } getFunctionPointer()178 llvm::Value *getFunctionPointer() const { 179 assert(isOrdinary()); 180 return reinterpret_cast<llvm::Value*>(uintptr_t(KindOrFunctionPointer)); 181 } setFunctionPointer(llvm::Value * functionPtr)182 void setFunctionPointer(llvm::Value *functionPtr) { 183 assert(isOrdinary()); 184 KindOrFunctionPointer = SpecialKind(uintptr_t(functionPtr)); 185 } 186 isVirtual()187 bool isVirtual() const { 188 return KindOrFunctionPointer == SpecialKind::Virtual; 189 } getVirtualCallExpr()190 const CallExpr *getVirtualCallExpr() const { 191 assert(isVirtual()); 192 return VirtualInfo.CE; 193 } getVirtualMethodDecl()194 GlobalDecl getVirtualMethodDecl() const { 195 assert(isVirtual()); 196 return VirtualInfo.MD; 197 } getThisAddress()198 Address getThisAddress() const { 199 assert(isVirtual()); 200 return VirtualInfo.Addr; 201 } 202 getFunctionType()203 llvm::FunctionType *getFunctionType() const { 204 if (isVirtual()) 205 return VirtualInfo.FTy; 206 return cast<llvm::FunctionType>( 207 getFunctionPointer()->getType()->getPointerElementType()); 208 } 209 210 /// If this is a delayed callee computation of some sort, prepare 211 /// a concrete callee. 212 CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const; 213 }; 214 215 struct CallArg { 216 private: 217 union { 218 RValue RV; 219 LValue LV; /// The argument is semantically a load from this l-value. 220 }; 221 bool HasLV; 222 223 /// A data-flow flag to make sure getRValue and/or copyInto are not 224 /// called twice for duplicated IR emission. 225 mutable bool IsUsed; 226 227 public: 228 QualType Ty; CallArgCallArg229 CallArg(RValue rv, QualType ty) 230 : RV(rv), HasLV(false), IsUsed(false), Ty(ty) {} CallArgCallArg231 CallArg(LValue lv, QualType ty) 232 : LV(lv), HasLV(true), IsUsed(false), Ty(ty) {} hasLValueCallArg233 bool hasLValue() const { return HasLV; } getTypeCallArg234 QualType getType() const { return Ty; } 235 236 /// \returns an independent RValue. If the CallArg contains an LValue, 237 /// a temporary copy is returned. 238 RValue getRValue(CodeGenFunction &CGF) const; 239 getKnownLValueCallArg240 LValue getKnownLValue() const { 241 assert(HasLV && !IsUsed); 242 return LV; 243 } getKnownRValueCallArg244 RValue getKnownRValue() const { 245 assert(!HasLV && !IsUsed); 246 return RV; 247 } setRValueCallArg248 void setRValue(RValue _RV) { 249 assert(!HasLV); 250 RV = _RV; 251 } 252 isAggregateCallArg253 bool isAggregate() const { return HasLV || RV.isAggregate(); } 254 255 void copyInto(CodeGenFunction &CGF, Address A) const; 256 }; 257 258 /// CallArgList - Type for representing both the value and type of 259 /// arguments in a call. 260 class CallArgList : 261 public SmallVector<CallArg, 8> { 262 public: CallArgList()263 CallArgList() : StackBase(nullptr) {} 264 265 struct Writeback { 266 /// The original argument. Note that the argument l-value 267 /// is potentially null. 268 LValue Source; 269 270 /// The temporary alloca. 271 Address Temporary; 272 273 /// A value to "use" after the writeback, or null. 274 llvm::Value *ToUse; 275 }; 276 277 struct CallArgCleanup { 278 EHScopeStack::stable_iterator Cleanup; 279 280 /// The "is active" insertion point. This instruction is temporary and 281 /// will be removed after insertion. 282 llvm::Instruction *IsActiveIP; 283 }; 284 add(RValue rvalue,QualType type)285 void add(RValue rvalue, QualType type) { push_back(CallArg(rvalue, type)); } 286 addUncopiedAggregate(LValue LV,QualType type)287 void addUncopiedAggregate(LValue LV, QualType type) { 288 push_back(CallArg(LV, type)); 289 } 290 291 /// Add all the arguments from another CallArgList to this one. After doing 292 /// this, the old CallArgList retains its list of arguments, but must not 293 /// be used to emit a call. addFrom(const CallArgList & other)294 void addFrom(const CallArgList &other) { 295 insert(end(), other.begin(), other.end()); 296 Writebacks.insert(Writebacks.end(), 297 other.Writebacks.begin(), other.Writebacks.end()); 298 CleanupsToDeactivate.insert(CleanupsToDeactivate.end(), 299 other.CleanupsToDeactivate.begin(), 300 other.CleanupsToDeactivate.end()); 301 assert(!(StackBase && other.StackBase) && "can't merge stackbases"); 302 if (!StackBase) 303 StackBase = other.StackBase; 304 } 305 addWriteback(LValue srcLV,Address temporary,llvm::Value * toUse)306 void addWriteback(LValue srcLV, Address temporary, 307 llvm::Value *toUse) { 308 Writeback writeback = { srcLV, temporary, toUse }; 309 Writebacks.push_back(writeback); 310 } 311 hasWritebacks()312 bool hasWritebacks() const { return !Writebacks.empty(); } 313 314 typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator> 315 writeback_const_range; 316 writebacks()317 writeback_const_range writebacks() const { 318 return writeback_const_range(Writebacks.begin(), Writebacks.end()); 319 } 320 addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,llvm::Instruction * IsActiveIP)321 void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup, 322 llvm::Instruction *IsActiveIP) { 323 CallArgCleanup ArgCleanup; 324 ArgCleanup.Cleanup = Cleanup; 325 ArgCleanup.IsActiveIP = IsActiveIP; 326 CleanupsToDeactivate.push_back(ArgCleanup); 327 } 328 getCleanupsToDeactivate()329 ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const { 330 return CleanupsToDeactivate; 331 } 332 333 void allocateArgumentMemory(CodeGenFunction &CGF); getStackBase()334 llvm::Instruction *getStackBase() const { return StackBase; } 335 void freeArgumentMemory(CodeGenFunction &CGF) const; 336 337 /// Returns if we're using an inalloca struct to pass arguments in 338 /// memory. isUsingInAlloca()339 bool isUsingInAlloca() const { return StackBase; } 340 341 private: 342 SmallVector<Writeback, 1> Writebacks; 343 344 /// Deactivate these cleanups immediately before making the call. This 345 /// is used to cleanup objects that are owned by the callee once the call 346 /// occurs. 347 SmallVector<CallArgCleanup, 1> CleanupsToDeactivate; 348 349 /// The stacksave call. It dominates all of the argument evaluation. 350 llvm::CallInst *StackBase; 351 }; 352 353 /// FunctionArgList - Type for representing both the decl and type 354 /// of parameters to a function. The decl must be either a 355 /// ParmVarDecl or ImplicitParamDecl. 356 class FunctionArgList : public SmallVector<const VarDecl*, 16> { 357 }; 358 359 /// ReturnValueSlot - Contains the address where the return value of a 360 /// function can be stored, and whether the address is volatile or not. 361 class ReturnValueSlot { 362 llvm::PointerIntPair<llvm::Value *, 2, unsigned int> Value; 363 CharUnits Alignment; 364 365 // Return value slot flags 366 enum Flags { 367 IS_VOLATILE = 0x1, 368 IS_UNUSED = 0x2, 369 }; 370 371 public: ReturnValueSlot()372 ReturnValueSlot() {} 373 ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false) 374 : Value(Addr.isValid() ? Addr.getPointer() : nullptr, 375 (IsVolatile ? IS_VOLATILE : 0) | (IsUnused ? IS_UNUSED : 0)), 376 Alignment(Addr.isValid() ? Addr.getAlignment() : CharUnits::Zero()) {} 377 isNull()378 bool isNull() const { return !getValue().isValid(); } 379 isVolatile()380 bool isVolatile() const { return Value.getInt() & IS_VOLATILE; } getValue()381 Address getValue() const { return Address(Value.getPointer(), Alignment); } isUnused()382 bool isUnused() const { return Value.getInt() & IS_UNUSED; } 383 }; 384 385 } // end namespace CodeGen 386 } // end namespace clang 387 388 #endif 389