1 //===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // These classes wrap the information about a call or function
10 // definition used to handle ABI compliancy.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_LIB_CODEGEN_CGCALL_H
15 #define LLVM_CLANG_LIB_CODEGEN_CGCALL_H
18 #include "EHScopeStack.h"
19 #include "clang/AST/CanonicalType.h"
20 #include "clang/AST/GlobalDecl.h"
21 #include "clang/AST/Type.h"
22 #include "llvm/IR/Value.h"
24 // FIXME: Restructure so we don't have to expose so much stuff.
43 /// Abstract information about a function or function prototype.
45 /// The function prototype of the callee.
46 const FunctionProtoType *CalleeProtoTy;
47 /// The function declaration of the callee.
48 GlobalDecl CalleeDecl;
51 explicit CGCalleeInfo() : CalleeProtoTy(nullptr), CalleeDecl() {}
52 CGCalleeInfo(const FunctionProtoType *calleeProtoTy, GlobalDecl calleeDecl)
53 : CalleeProtoTy(calleeProtoTy), CalleeDecl(calleeDecl) {}
54 CGCalleeInfo(const FunctionProtoType *calleeProtoTy)
55 : CalleeProtoTy(calleeProtoTy), CalleeDecl() {}
56 CGCalleeInfo(GlobalDecl calleeDecl)
57 : CalleeProtoTy(nullptr), CalleeDecl(calleeDecl) {}
59 const FunctionProtoType *getCalleeFunctionProtoType() const {
62 const GlobalDecl getCalleeDecl() const { return CalleeDecl; }
65 /// All available information about a concrete callee.
67 enum class SpecialKind : uintptr_t {
76 struct BuiltinInfoStorage {
77 const FunctionDecl *Decl;
80 struct PseudoDestructorInfoStorage {
81 const CXXPseudoDestructorExpr *Expr;
83 struct VirtualInfoStorage {
87 llvm::FunctionType *FTy;
90 SpecialKind KindOrFunctionPointer;
92 CGCalleeInfo AbstractInfo;
93 BuiltinInfoStorage BuiltinInfo;
94 PseudoDestructorInfoStorage PseudoDestructorInfo;
95 VirtualInfoStorage VirtualInfo;
98 explicit CGCallee(SpecialKind kind) : KindOrFunctionPointer(kind) {}
100 CGCallee(const FunctionDecl *builtinDecl, unsigned builtinID)
101 : KindOrFunctionPointer(SpecialKind::Builtin) {
102 BuiltinInfo.Decl = builtinDecl;
103 BuiltinInfo.ID = builtinID;
107 CGCallee() : KindOrFunctionPointer(SpecialKind::Invalid) {}
109 /// Construct a callee. Call this constructor directly when this
110 /// isn't a direct call.
111 CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr)
112 : KindOrFunctionPointer(SpecialKind(uintptr_t(functionPtr))) {
113 AbstractInfo = abstractInfo;
114 assert(functionPtr && "configuring callee without function pointer");
115 assert(functionPtr->getType()->isPointerTy());
116 assert(functionPtr->getType()->getPointerElementType()->isFunctionTy());
119 static CGCallee forBuiltin(unsigned builtinID,
120 const FunctionDecl *builtinDecl) {
121 CGCallee result(SpecialKind::Builtin);
122 result.BuiltinInfo.Decl = builtinDecl;
123 result.BuiltinInfo.ID = builtinID;
127 static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E) {
128 CGCallee result(SpecialKind::PseudoDestructor);
129 result.PseudoDestructorInfo.Expr = E;
133 static CGCallee forDirect(llvm::Constant *functionPtr,
134 const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
135 return CGCallee(abstractInfo, functionPtr);
139 forDirect(llvm::FunctionCallee functionPtr,
140 const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
141 return CGCallee(abstractInfo, functionPtr.getCallee());
144 static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr,
145 llvm::FunctionType *FTy) {
146 CGCallee result(SpecialKind::Virtual);
147 result.VirtualInfo.CE = CE;
148 result.VirtualInfo.MD = MD;
149 result.VirtualInfo.Addr = Addr;
150 result.VirtualInfo.FTy = FTy;
154 bool isBuiltin() const {
155 return KindOrFunctionPointer == SpecialKind::Builtin;
157 const FunctionDecl *getBuiltinDecl() const {
159 return BuiltinInfo.Decl;
161 unsigned getBuiltinID() const {
163 return BuiltinInfo.ID;
166 bool isPseudoDestructor() const {
167 return KindOrFunctionPointer == SpecialKind::PseudoDestructor;
169 const CXXPseudoDestructorExpr *getPseudoDestructorExpr() const {
170 assert(isPseudoDestructor());
171 return PseudoDestructorInfo.Expr;
174 bool isOrdinary() const {
175 return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last);
177 CGCalleeInfo getAbstractInfo() const {
179 return VirtualInfo.MD;
180 assert(isOrdinary());
183 llvm::Value *getFunctionPointer() const {
184 assert(isOrdinary());
185 return reinterpret_cast<llvm::Value*>(uintptr_t(KindOrFunctionPointer));
187 void setFunctionPointer(llvm::Value *functionPtr) {
188 assert(isOrdinary());
189 KindOrFunctionPointer = SpecialKind(uintptr_t(functionPtr));
192 bool isVirtual() const {
193 return KindOrFunctionPointer == SpecialKind::Virtual;
195 const CallExpr *getVirtualCallExpr() const {
197 return VirtualInfo.CE;
199 GlobalDecl getVirtualMethodDecl() const {
201 return VirtualInfo.MD;
203 Address getThisAddress() const {
205 return VirtualInfo.Addr;
207 llvm::FunctionType *getVirtualFunctionType() const {
209 return VirtualInfo.FTy;
212 /// If this is a delayed callee computation of some sort, prepare
213 /// a concrete callee.
214 CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const;
221 LValue LV; /// The argument is semantically a load from this l-value.
225 /// A data-flow flag to make sure getRValue and/or copyInto are not
226 /// called twice for duplicated IR emission.
231 CallArg(RValue rv, QualType ty)
232 : RV(rv), HasLV(false), IsUsed(false), Ty(ty) {}
233 CallArg(LValue lv, QualType ty)
234 : LV(lv), HasLV(true), IsUsed(false), Ty(ty) {}
235 bool hasLValue() const { return HasLV; }
236 QualType getType() const { return Ty; }
238 /// \returns an independent RValue. If the CallArg contains an LValue,
239 /// a temporary copy is returned.
240 RValue getRValue(CodeGenFunction &CGF) const;
242 LValue getKnownLValue() const {
243 assert(HasLV && !IsUsed);
246 RValue getKnownRValue() const {
247 assert(!HasLV && !IsUsed);
250 void setRValue(RValue _RV) {
255 bool isAggregate() const { return HasLV || RV.isAggregate(); }
257 void copyInto(CodeGenFunction &CGF, Address A) const;
260 /// CallArgList - Type for representing both the value and type of
261 /// arguments in a call.
263 public SmallVector<CallArg, 8> {
265 CallArgList() : StackBase(nullptr) {}
268 /// The original argument. Note that the argument l-value
269 /// is potentially null.
272 /// The temporary alloca.
275 /// A value to "use" after the writeback, or null.
279 struct CallArgCleanup {
280 EHScopeStack::stable_iterator Cleanup;
282 /// The "is active" insertion point. This instruction is temporary and
283 /// will be removed after insertion.
284 llvm::Instruction *IsActiveIP;
287 void add(RValue rvalue, QualType type) { push_back(CallArg(rvalue, type)); }
289 void addUncopiedAggregate(LValue LV, QualType type) {
290 push_back(CallArg(LV, type));
293 /// Add all the arguments from another CallArgList to this one. After doing
294 /// this, the old CallArgList retains its list of arguments, but must not
295 /// be used to emit a call.
296 void addFrom(const CallArgList &other) {
297 insert(end(), other.begin(), other.end());
298 Writebacks.insert(Writebacks.end(),
299 other.Writebacks.begin(), other.Writebacks.end());
300 CleanupsToDeactivate.insert(CleanupsToDeactivate.end(),
301 other.CleanupsToDeactivate.begin(),
302 other.CleanupsToDeactivate.end());
303 assert(!(StackBase && other.StackBase) && "can't merge stackbases");
305 StackBase = other.StackBase;
308 void addWriteback(LValue srcLV, Address temporary,
309 llvm::Value *toUse) {
310 Writeback writeback = { srcLV, temporary, toUse };
311 Writebacks.push_back(writeback);
314 bool hasWritebacks() const { return !Writebacks.empty(); }
316 typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
317 writeback_const_range;
319 writeback_const_range writebacks() const {
320 return writeback_const_range(Writebacks.begin(), Writebacks.end());
323 void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,
324 llvm::Instruction *IsActiveIP) {
325 CallArgCleanup ArgCleanup;
326 ArgCleanup.Cleanup = Cleanup;
327 ArgCleanup.IsActiveIP = IsActiveIP;
328 CleanupsToDeactivate.push_back(ArgCleanup);
331 ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const {
332 return CleanupsToDeactivate;
335 void allocateArgumentMemory(CodeGenFunction &CGF);
336 llvm::Instruction *getStackBase() const { return StackBase; }
337 void freeArgumentMemory(CodeGenFunction &CGF) const;
339 /// Returns if we're using an inalloca struct to pass arguments in
341 bool isUsingInAlloca() const { return StackBase; }
344 SmallVector<Writeback, 1> Writebacks;
346 /// Deactivate these cleanups immediately before making the call. This
347 /// is used to cleanup objects that are owned by the callee once the call
349 SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
351 /// The stacksave call. It dominates all of the argument evaluation.
352 llvm::CallInst *StackBase;
355 /// FunctionArgList - Type for representing both the decl and type
356 /// of parameters to a function. The decl must be either a
357 /// ParmVarDecl or ImplicitParamDecl.
358 class FunctionArgList : public SmallVector<const VarDecl*, 16> {
361 /// ReturnValueSlot - Contains the address where the return value of a
362 /// function can be stored, and whether the address is volatile or not.
363 class ReturnValueSlot {
364 llvm::PointerIntPair<llvm::Value *, 2, unsigned int> Value;
367 // Return value slot flags
375 ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false)
376 : Value(Addr.isValid() ? Addr.getPointer() : nullptr,
377 (IsVolatile ? IS_VOLATILE : 0) | (IsUnused ? IS_UNUSED : 0)),
378 Alignment(Addr.isValid() ? Addr.getAlignment() : CharUnits::Zero()) {}
380 bool isNull() const { return !getValue().isValid(); }
382 bool isVolatile() const { return Value.getInt() & IS_VOLATILE; }
383 Address getValue() const { return Address(Value.getPointer(), Alignment); }
384 bool isUnused() const { return Value.getInt() & IS_UNUSED; }
387 } // end namespace CodeGen
388 } // end namespace clang