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//===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// These classes wrap the information about a call or function
// definition used to handle ABI compliancy.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_LIB_CODEGEN_CGCALL_H
#define LLVM_CLANG_LIB_CODEGEN_CGCALL_H
#include "CGValue.h"
#include "EHScopeStack.h"
#include "clang/AST/ASTFwd.h"
#include "clang/AST/CanonicalType.h"
#include "clang/AST/GlobalDecl.h"
#include "clang/AST/Type.h"
#include "llvm/IR/Value.h"
// FIXME: Restructure so we don't have to expose so much stuff.
#include "ABIInfo.h"
namespace llvm {
class AttributeList;
class Function;
class Type;
class Value;
} // namespace llvm
namespace clang {
class ASTContext;
class Decl;
class FunctionDecl;
class ObjCMethodDecl;
class VarDecl;
namespace CodeGen {
/// Abstract information about a function or function prototype.
class CGCalleeInfo {
/// The function prototype of the callee.
const FunctionProtoType *CalleeProtoTy;
/// The function declaration of the callee.
GlobalDecl CalleeDecl;
public:
explicit CGCalleeInfo() : CalleeProtoTy(nullptr), CalleeDecl() {}
CGCalleeInfo(const FunctionProtoType *calleeProtoTy, GlobalDecl calleeDecl)
: CalleeProtoTy(calleeProtoTy), CalleeDecl(calleeDecl) {}
CGCalleeInfo(const FunctionProtoType *calleeProtoTy)
: CalleeProtoTy(calleeProtoTy), CalleeDecl() {}
CGCalleeInfo(GlobalDecl calleeDecl)
: CalleeProtoTy(nullptr), CalleeDecl(calleeDecl) {}
const FunctionProtoType *getCalleeFunctionProtoType() const {
return CalleeProtoTy;
}
const GlobalDecl getCalleeDecl() const { return CalleeDecl; }
};
/// All available information about a concrete callee.
class CGCallee {
enum class SpecialKind : uintptr_t {
Invalid,
Builtin,
PseudoDestructor,
Virtual,
Last = Virtual
};
struct BuiltinInfoStorage {
const FunctionDecl *Decl;
unsigned ID;
};
struct PseudoDestructorInfoStorage {
const CXXPseudoDestructorExpr *Expr;
};
struct VirtualInfoStorage {
const CallExpr *CE;
GlobalDecl MD;
Address Addr;
llvm::FunctionType *FTy;
};
SpecialKind KindOrFunctionPointer;
union {
CGCalleeInfo AbstractInfo;
BuiltinInfoStorage BuiltinInfo;
PseudoDestructorInfoStorage PseudoDestructorInfo;
VirtualInfoStorage VirtualInfo;
};
explicit CGCallee(SpecialKind kind) : KindOrFunctionPointer(kind) {}
CGCallee(const FunctionDecl *builtinDecl, unsigned builtinID)
: KindOrFunctionPointer(SpecialKind::Builtin) {
BuiltinInfo.Decl = builtinDecl;
BuiltinInfo.ID = builtinID;
}
public:
CGCallee() : KindOrFunctionPointer(SpecialKind::Invalid) {}
/// Construct a callee. Call this constructor directly when this
/// isn't a direct call.
CGCallee(const CGCalleeInfo &abstractInfo, llvm::Value *functionPtr)
: KindOrFunctionPointer(
SpecialKind(reinterpret_cast<uintptr_t>(functionPtr))) {
AbstractInfo = abstractInfo;
assert(functionPtr && "configuring callee without function pointer");
assert(functionPtr->getType()->isPointerTy());
assert(functionPtr->getType()->getPointerElementType()->isFunctionTy());
}
static CGCallee forBuiltin(unsigned builtinID,
const FunctionDecl *builtinDecl) {
CGCallee result(SpecialKind::Builtin);
result.BuiltinInfo.Decl = builtinDecl;
result.BuiltinInfo.ID = builtinID;
return result;
}
static CGCallee forPseudoDestructor(const CXXPseudoDestructorExpr *E) {
CGCallee result(SpecialKind::PseudoDestructor);
result.PseudoDestructorInfo.Expr = E;
return result;
}
static CGCallee forDirect(llvm::Constant *functionPtr,
const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
return CGCallee(abstractInfo, functionPtr);
}
static CGCallee forDirect(llvm::FunctionCallee functionPtr,
const CGCalleeInfo &abstractInfo = CGCalleeInfo()) {
return CGCallee(abstractInfo, functionPtr.getCallee());
}
static CGCallee forVirtual(const CallExpr *CE, GlobalDecl MD, Address Addr,
llvm::FunctionType *FTy) {
CGCallee result(SpecialKind::Virtual);
result.VirtualInfo.CE = CE;
result.VirtualInfo.MD = MD;
result.VirtualInfo.Addr = Addr;
result.VirtualInfo.FTy = FTy;
return result;
}
bool isBuiltin() const {
return KindOrFunctionPointer == SpecialKind::Builtin;
}
const FunctionDecl *getBuiltinDecl() const {
assert(isBuiltin());
return BuiltinInfo.Decl;
}
unsigned getBuiltinID() const {
assert(isBuiltin());
return BuiltinInfo.ID;
}
bool isPseudoDestructor() const {
return KindOrFunctionPointer == SpecialKind::PseudoDestructor;
}
const CXXPseudoDestructorExpr *getPseudoDestructorExpr() const {
assert(isPseudoDestructor());
return PseudoDestructorInfo.Expr;
}
bool isOrdinary() const {
return uintptr_t(KindOrFunctionPointer) > uintptr_t(SpecialKind::Last);
}
CGCalleeInfo getAbstractInfo() const {
if (isVirtual())
return VirtualInfo.MD;
assert(isOrdinary());
return AbstractInfo;
}
llvm::Value *getFunctionPointer() const {
assert(isOrdinary());
return reinterpret_cast<llvm::Value *>(uintptr_t(KindOrFunctionPointer));
}
void setFunctionPointer(llvm::Value *functionPtr) {
assert(isOrdinary());
KindOrFunctionPointer =
SpecialKind(reinterpret_cast<uintptr_t>(functionPtr));
}
bool isVirtual() const {
return KindOrFunctionPointer == SpecialKind::Virtual;
}
const CallExpr *getVirtualCallExpr() const {
assert(isVirtual());
return VirtualInfo.CE;
}
GlobalDecl getVirtualMethodDecl() const {
assert(isVirtual());
return VirtualInfo.MD;
}
Address getThisAddress() const {
assert(isVirtual());
return VirtualInfo.Addr;
}
llvm::FunctionType *getVirtualFunctionType() const {
assert(isVirtual());
return VirtualInfo.FTy;
}
/// If this is a delayed callee computation of some sort, prepare
/// a concrete callee.
CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const;
};
struct CallArg {
private:
union {
RValue RV;
LValue LV; /// The argument is semantically a load from this l-value.
};
bool HasLV;
/// A data-flow flag to make sure getRValue and/or copyInto are not
/// called twice for duplicated IR emission.
mutable bool IsUsed;
public:
QualType Ty;
CallArg(RValue rv, QualType ty)
: RV(rv), HasLV(false), IsUsed(false), Ty(ty) {}
CallArg(LValue lv, QualType ty)
: LV(lv), HasLV(true), IsUsed(false), Ty(ty) {}
bool hasLValue() const { return HasLV; }
QualType getType() const { return Ty; }
/// \returns an independent RValue. If the CallArg contains an LValue,
/// a temporary copy is returned.
RValue getRValue(CodeGenFunction &CGF) const;
LValue getKnownLValue() const {
assert(HasLV && !IsUsed);
return LV;
}
RValue getKnownRValue() const {
assert(!HasLV && !IsUsed);
return RV;
}
void setRValue(RValue _RV) {
assert(!HasLV);
RV = _RV;
}
bool isAggregate() const { return HasLV || RV.isAggregate(); }
void copyInto(CodeGenFunction &CGF, Address A) const;
};
/// CallArgList - Type for representing both the value and type of
/// arguments in a call.
class CallArgList : public SmallVector<CallArg, 8> {
public:
CallArgList() : StackBase(nullptr) {}
struct Writeback {
/// The original argument. Note that the argument l-value
/// is potentially null.
LValue Source;
/// The temporary alloca.
Address Temporary;
/// A value to "use" after the writeback, or null.
llvm::Value *ToUse;
};
struct CallArgCleanup {
EHScopeStack::stable_iterator Cleanup;
/// The "is active" insertion point. This instruction is temporary and
/// will be removed after insertion.
llvm::Instruction *IsActiveIP;
};
void add(RValue rvalue, QualType type) { push_back(CallArg(rvalue, type)); }
void addUncopiedAggregate(LValue LV, QualType type) {
push_back(CallArg(LV, type));
}
/// Add all the arguments from another CallArgList to this one. After doing
/// this, the old CallArgList retains its list of arguments, but must not
/// be used to emit a call.
void addFrom(const CallArgList &other) {
insert(end(), other.begin(), other.end());
Writebacks.insert(Writebacks.end(), other.Writebacks.begin(),
other.Writebacks.end());
CleanupsToDeactivate.insert(CleanupsToDeactivate.end(),
other.CleanupsToDeactivate.begin(),
other.CleanupsToDeactivate.end());
assert(!(StackBase && other.StackBase) && "can't merge stackbases");
if (!StackBase)
StackBase = other.StackBase;
}
void addWriteback(LValue srcLV, Address temporary, llvm::Value *toUse) {
Writeback writeback = {srcLV, temporary, toUse};
Writebacks.push_back(writeback);
}
bool hasWritebacks() const { return !Writebacks.empty(); }
typedef llvm::iterator_range<SmallVectorImpl<Writeback>::const_iterator>
writeback_const_range;
writeback_const_range writebacks() const {
return writeback_const_range(Writebacks.begin(), Writebacks.end());
}
void addArgCleanupDeactivation(EHScopeStack::stable_iterator Cleanup,
llvm::Instruction *IsActiveIP) {
CallArgCleanup ArgCleanup;
ArgCleanup.Cleanup = Cleanup;
ArgCleanup.IsActiveIP = IsActiveIP;
CleanupsToDeactivate.push_back(ArgCleanup);
}
ArrayRef<CallArgCleanup> getCleanupsToDeactivate() const {
return CleanupsToDeactivate;
}
void allocateArgumentMemory(CodeGenFunction &CGF);
llvm::Instruction *getStackBase() const { return StackBase; }
void freeArgumentMemory(CodeGenFunction &CGF) const;
/// Returns if we're using an inalloca struct to pass arguments in
/// memory.
bool isUsingInAlloca() const { return StackBase; }
private:
SmallVector<Writeback, 1> Writebacks;
/// Deactivate these cleanups immediately before making the call. This
/// is used to cleanup objects that are owned by the callee once the call
/// occurs.
SmallVector<CallArgCleanup, 1> CleanupsToDeactivate;
/// The stacksave call. It dominates all of the argument evaluation.
llvm::CallInst *StackBase;
};
/// FunctionArgList - Type for representing both the decl and type
/// of parameters to a function. The decl must be either a
/// ParmVarDecl or ImplicitParamDecl.
class FunctionArgList : public SmallVector<const VarDecl *, 16> {};
/// ReturnValueSlot - Contains the address where the return value of a
/// function can be stored, and whether the address is volatile or not.
class ReturnValueSlot {
Address Addr = Address::invalid();
// Return value slot flags
unsigned IsVolatile : 1;
unsigned IsUnused : 1;
unsigned IsExternallyDestructed : 1;
public:
ReturnValueSlot()
: IsVolatile(false), IsUnused(false), IsExternallyDestructed(false) {}
ReturnValueSlot(Address Addr, bool IsVolatile, bool IsUnused = false,
bool IsExternallyDestructed = false)
: Addr(Addr), IsVolatile(IsVolatile), IsUnused(IsUnused),
IsExternallyDestructed(IsExternallyDestructed) {}
bool isNull() const { return !Addr.isValid(); }
bool isVolatile() const { return IsVolatile; }
Address getValue() const { return Addr; }
bool isUnused() const { return IsUnused; }
bool isExternallyDestructed() const { return IsExternallyDestructed; }
};
} // end namespace CodeGen
} // end namespace clang
#endif