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llvm-project/clang/lib/CodeGen/TargetABIInfo.cpp

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//===---- TargetABIInfo.cpp - Encapsulate target ABI details ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// These classes wrap the information about a call or function
// definition used to handle ABI compliancy.
//
//===----------------------------------------------------------------------===//
#include "ABIInfo.h"
#include "CodeGenFunction.h"
#include "clang/AST/RecordLayout.h"
#include "llvm/Type.h"
#include "llvm/ADT/Triple.h"
#include <cstdio>
using namespace clang;
using namespace CodeGen;
ABIInfo::~ABIInfo() {}
void ABIArgInfo::dump() const {
fprintf(stderr, "(ABIArgInfo Kind=");
switch (TheKind) {
case Direct:
fprintf(stderr, "Direct");
break;
case Extend:
fprintf(stderr, "Extend");
break;
case Ignore:
fprintf(stderr, "Ignore");
break;
case Coerce:
fprintf(stderr, "Coerce Type=");
getCoerceToType()->print(llvm::errs());
break;
case Indirect:
fprintf(stderr, "Indirect Align=%d", getIndirectAlign());
break;
case Expand:
fprintf(stderr, "Expand");
break;
}
fprintf(stderr, ")\n");
}
static bool isEmptyRecord(ASTContext &Context, QualType T, bool AllowArrays);
/// isEmptyField - Return true iff a the field is "empty", that is it
/// is an unnamed bit-field or an (array of) empty record(s).
static bool isEmptyField(ASTContext &Context, const FieldDecl *FD,
bool AllowArrays) {
if (FD->isUnnamedBitfield())
return true;
QualType FT = FD->getType();
// Constant arrays of empty records count as empty, strip them off.
if (AllowArrays)
while (const ConstantArrayType *AT = Context.getAsConstantArrayType(FT))
FT = AT->getElementType();
return isEmptyRecord(Context, FT, AllowArrays);
}
/// isEmptyRecord - Return true iff a structure contains only empty
/// fields. Note that a structure with a flexible array member is not
/// considered empty.
static bool isEmptyRecord(ASTContext &Context, QualType T, bool AllowArrays) {
const RecordType *RT = T->getAs<RecordType>();
if (!RT)
return 0;
const RecordDecl *RD = RT->getDecl();
if (RD->hasFlexibleArrayMember())
return false;
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i)
if (!isEmptyField(Context, *i, AllowArrays))
return false;
return true;
}
/// hasNonTrivialDestructorOrCopyConstructor - Determine if a type has either
/// a non-trivial destructor or a non-trivial copy constructor.
static bool hasNonTrivialDestructorOrCopyConstructor(const RecordType *RT) {
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
if (!RD)
return false;
return !RD->hasTrivialDestructor() || !RD->hasTrivialCopyConstructor();
}
/// isRecordWithNonTrivialDestructorOrCopyConstructor - Determine if a type is
/// a record type with either a non-trivial destructor or a non-trivial copy
/// constructor.
static bool isRecordWithNonTrivialDestructorOrCopyConstructor(QualType T) {
const RecordType *RT = T->getAs<RecordType>();
if (!RT)
return false;
return hasNonTrivialDestructorOrCopyConstructor(RT);
}
/// isSingleElementStruct - Determine if a structure is a "single
/// element struct", i.e. it has exactly one non-empty field or
/// exactly one field which is itself a single element
/// struct. Structures with flexible array members are never
/// considered single element structs.
///
/// \return The field declaration for the single non-empty field, if
/// it exists.
static const Type *isSingleElementStruct(QualType T, ASTContext &Context) {
const RecordType *RT = T->getAsStructureType();
if (!RT)
return 0;
const RecordDecl *RD = RT->getDecl();
if (RD->hasFlexibleArrayMember())
return 0;
const Type *Found = 0;
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
const FieldDecl *FD = *i;
QualType FT = FD->getType();
// Ignore empty fields.
if (isEmptyField(Context, FD, true))
continue;
// If we already found an element then this isn't a single-element
// struct.
if (Found)
return 0;
// Treat single element arrays as the element.
while (const ConstantArrayType *AT = Context.getAsConstantArrayType(FT)) {
if (AT->getSize().getZExtValue() != 1)
break;
FT = AT->getElementType();
}
if (!CodeGenFunction::hasAggregateLLVMType(FT)) {
Found = FT.getTypePtr();
} else {
Found = isSingleElementStruct(FT, Context);
if (!Found)
return 0;
}
}
return Found;
}
static bool is32Or64BitBasicType(QualType Ty, ASTContext &Context) {
if (!Ty->getAs<BuiltinType>() && !Ty->isAnyPointerType() &&
!Ty->isAnyComplexType() && !Ty->isEnumeralType() &&
!Ty->isBlockPointerType())
return false;
uint64_t Size = Context.getTypeSize(Ty);
return Size == 32 || Size == 64;
}
static bool areAllFields32Or64BitBasicType(const RecordDecl *RD,
ASTContext &Context) {
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
const FieldDecl *FD = *i;
if (!is32Or64BitBasicType(FD->getType(), Context))
return false;
// FIXME: Reject bit-fields wholesale; there are two problems, we don't know
// how to expand them yet, and the predicate for telling if a bitfield still
// counts as "basic" is more complicated than what we were doing previously.
if (FD->isBitField())
return false;
}
return true;
}
static bool typeContainsSSEVector(const RecordDecl *RD, ASTContext &Context) {
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i) {
const FieldDecl *FD = *i;
if (FD->getType()->isVectorType() &&
Context.getTypeSize(FD->getType()) >= 128)
return true;
if (const RecordType* RT = FD->getType()->getAs<RecordType>())
if (typeContainsSSEVector(RT->getDecl(), Context))
return true;
}
return false;
}
namespace {
/// DefaultABIInfo - The default implementation for ABI specific
/// details. This implementation provides information which results in
/// self-consistent and sensible LLVM IR generation, but does not
/// conform to any particular ABI.
class DefaultABIInfo : public ABIInfo {
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
ABIArgInfo classifyArgumentType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), Context,
VMContext);
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it)
it->info = classifyArgumentType(it->type, Context, VMContext);
}
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
};
/// X86_32ABIInfo - The X86-32 ABI information.
class X86_32ABIInfo : public ABIInfo {
ASTContext &Context;
bool IsDarwinVectorABI;
bool IsSmallStructInRegABI;
static bool isRegisterSize(unsigned Size) {
return (Size == 8 || Size == 16 || Size == 32 || Size == 64);
}
static bool shouldReturnTypeInRegister(QualType Ty, ASTContext &Context);
static unsigned getIndirectArgumentAlignment(QualType Ty,
ASTContext &Context);
public:
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
ABIArgInfo classifyArgumentType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), Context,
VMContext);
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it)
it->info = classifyArgumentType(it->type, Context, VMContext);
}
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
X86_32ABIInfo(ASTContext &Context, bool d, bool p)
: ABIInfo(), Context(Context), IsDarwinVectorABI(d),
IsSmallStructInRegABI(p) {}
};
}
/// shouldReturnTypeInRegister - Determine if the given type should be
/// passed in a register (for the Darwin ABI).
bool X86_32ABIInfo::shouldReturnTypeInRegister(QualType Ty,
ASTContext &Context) {
uint64_t Size = Context.getTypeSize(Ty);
// Type must be register sized.
if (!isRegisterSize(Size))
return false;
if (Ty->isVectorType()) {
// 64- and 128- bit vectors inside structures are not returned in
// registers.
if (Size == 64 || Size == 128)
return false;
return true;
}
// If this is a builtin, pointer, enum, or complex type, it is ok.
if (Ty->getAs<BuiltinType>() || Ty->isAnyPointerType() ||
Ty->isAnyComplexType() || Ty->isEnumeralType() ||
Ty->isBlockPointerType())
return true;
// Arrays are treated like records.
if (const ConstantArrayType *AT = Context.getAsConstantArrayType(Ty))
return shouldReturnTypeInRegister(AT->getElementType(), Context);
// Otherwise, it must be a record type.
const RecordType *RT = Ty->getAs<RecordType>();
if (!RT) return false;
// Structure types are passed in register if all fields would be
// passed in a register.
for (RecordDecl::field_iterator i = RT->getDecl()->field_begin(),
e = RT->getDecl()->field_end(); i != e; ++i) {
const FieldDecl *FD = *i;
// Empty fields are ignored.
if (isEmptyField(Context, FD, true))
continue;
// Check fields recursively.
if (!shouldReturnTypeInRegister(FD->getType(), Context))
return false;
}
return true;
}
ABIArgInfo X86_32ABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (RetTy->isVoidType()) {
return ABIArgInfo::getIgnore();
} else if (const VectorType *VT = RetTy->getAs<VectorType>()) {
// On Darwin, some vectors are returned in registers.
if (IsDarwinVectorABI) {
uint64_t Size = Context.getTypeSize(RetTy);
// 128-bit vectors are a special case; they are returned in
// registers and we need to make sure to pick a type the LLVM
// backend will like.
if (Size == 128)
return ABIArgInfo::getCoerce(llvm::VectorType::get(
llvm::Type::getInt64Ty(VMContext), 2));
// Always return in register if it fits in a general purpose
// register, or if it is 64 bits and has a single element.
if ((Size == 8 || Size == 16 || Size == 32) ||
(Size == 64 && VT->getNumElements() == 1))
return ABIArgInfo::getCoerce(llvm::IntegerType::get(VMContext, Size));
return ABIArgInfo::getIndirect(0);
}
return ABIArgInfo::getDirect();
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
// Structures with flexible arrays are always indirect.
if (const RecordType *RT = RetTy->getAsStructureType())
if (RT->getDecl()->hasFlexibleArrayMember())
return ABIArgInfo::getIndirect(0);
// If specified, structs and unions are always indirect.
if (!IsSmallStructInRegABI && !RetTy->isAnyComplexType())
return ABIArgInfo::getIndirect(0);
// Classify "single element" structs as their element type.
if (const Type *SeltTy = isSingleElementStruct(RetTy, Context)) {
if (const BuiltinType *BT = SeltTy->getAs<BuiltinType>()) {
if (BT->isIntegerType()) {
// We need to use the size of the structure, padding
// bit-fields can adjust that to be larger than the single
// element type.
uint64_t Size = Context.getTypeSize(RetTy);
return ABIArgInfo::getCoerce(
llvm::IntegerType::get(VMContext, (unsigned) Size));
} else if (BT->getKind() == BuiltinType::Float) {
assert(Context.getTypeSize(RetTy) == Context.getTypeSize(SeltTy) &&
"Unexpect single element structure size!");
return ABIArgInfo::getCoerce(llvm::Type::getFloatTy(VMContext));
} else if (BT->getKind() == BuiltinType::Double) {
assert(Context.getTypeSize(RetTy) == Context.getTypeSize(SeltTy) &&
"Unexpect single element structure size!");
return ABIArgInfo::getCoerce(llvm::Type::getDoubleTy(VMContext));
}
} else if (SeltTy->isPointerType()) {
// FIXME: It would be really nice if this could come out as the proper
// pointer type.
llvm::Type *PtrTy =
llvm::PointerType::getUnqual(llvm::Type::getInt8Ty(VMContext));
return ABIArgInfo::getCoerce(PtrTy);
} else if (SeltTy->isVectorType()) {
// 64- and 128-bit vectors are never returned in a
// register when inside a structure.
uint64_t Size = Context.getTypeSize(RetTy);
if (Size == 64 || Size == 128)
return ABIArgInfo::getIndirect(0);
return classifyReturnType(QualType(SeltTy, 0), Context, VMContext);
}
}
// Small structures which are register sized are generally returned
// in a register.
if (X86_32ABIInfo::shouldReturnTypeInRegister(RetTy, Context)) {
uint64_t Size = Context.getTypeSize(RetTy);
return ABIArgInfo::getCoerce(llvm::IntegerType::get(VMContext, Size));
}
return ABIArgInfo::getIndirect(0);
} else {
return (RetTy->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
}
unsigned X86_32ABIInfo::getIndirectArgumentAlignment(QualType Ty,
ASTContext &Context) {
unsigned Align = Context.getTypeAlign(Ty);
if (Align < 128) return 0;
if (const RecordType* RT = Ty->getAs<RecordType>())
if (typeContainsSSEVector(RT->getDecl(), Context))
return 16;
return 0;
}
ABIArgInfo X86_32ABIInfo::classifyArgumentType(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
// FIXME: Set alignment on indirect arguments.
if (CodeGenFunction::hasAggregateLLVMType(Ty)) {
// Structures with flexible arrays are always indirect.
if (const RecordType *RT = Ty->getAsStructureType())
if (RT->getDecl()->hasFlexibleArrayMember())
return ABIArgInfo::getIndirect(getIndirectArgumentAlignment(Ty,
Context));
// Ignore empty structs.
if (Ty->isStructureType() && Context.getTypeSize(Ty) == 0)
return ABIArgInfo::getIgnore();
// Expand structs with size <= 128-bits which consist only of
// basic types (int, long long, float, double, xxx*). This is
// non-recursive and does not ignore empty fields.
if (const RecordType *RT = Ty->getAsStructureType()) {
if (Context.getTypeSize(Ty) <= 4*32 &&
areAllFields32Or64BitBasicType(RT->getDecl(), Context))
return ABIArgInfo::getExpand();
}
return ABIArgInfo::getIndirect(getIndirectArgumentAlignment(Ty, Context));
} else {
return (Ty->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
}
llvm::Value *X86_32ABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const {
const llvm::Type *BP = llvm::PointerType::getUnqual(llvm::Type::getInt8Ty(CGF.getLLVMContext()));
const llvm::Type *BPP = llvm::PointerType::getUnqual(BP);
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *VAListAddrAsBPP = Builder.CreateBitCast(VAListAddr, BPP,
"ap");
llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP, "ap.cur");
llvm::Type *PTy =
llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
llvm::Value *AddrTyped = Builder.CreateBitCast(Addr, PTy);
uint64_t Offset =
llvm::RoundUpToAlignment(CGF.getContext().getTypeSize(Ty) / 8, 4);
llvm::Value *NextAddr =
Builder.CreateGEP(Addr, llvm::ConstantInt::get(
llvm::Type::getInt32Ty(CGF.getLLVMContext()), Offset),
"ap.next");
Builder.CreateStore(NextAddr, VAListAddrAsBPP);
return AddrTyped;
}
namespace {
/// X86_64ABIInfo - The X86_64 ABI information.
class X86_64ABIInfo : public ABIInfo {
enum Class {
Integer = 0,
SSE,
SSEUp,
X87,
X87Up,
ComplexX87,
NoClass,
Memory
};
/// merge - Implement the X86_64 ABI merging algorithm.
///
/// Merge an accumulating classification \arg Accum with a field
/// classification \arg Field.
///
/// \param Accum - The accumulating classification. This should
/// always be either NoClass or the result of a previous merge
/// call. In addition, this should never be Memory (the caller
/// should just return Memory for the aggregate).
Class merge(Class Accum, Class Field) const;
/// classify - Determine the x86_64 register classes in which the
/// given type T should be passed.
///
/// \param Lo - The classification for the parts of the type
/// residing in the low word of the containing object.
///
/// \param Hi - The classification for the parts of the type
/// residing in the high word of the containing object.
///
/// \param OffsetBase - The bit offset of this type in the
/// containing object. Some parameters are classified different
/// depending on whether they straddle an eightbyte boundary.
///
/// If a word is unused its result will be NoClass; if a type should
/// be passed in Memory then at least the classification of \arg Lo
/// will be Memory.
///
/// The \arg Lo class will be NoClass iff the argument is ignored.
///
/// If the \arg Lo class is ComplexX87, then the \arg Hi class will
/// also be ComplexX87.
void classify(QualType T, ASTContext &Context, uint64_t OffsetBase,
Class &Lo, Class &Hi) const;
/// getCoerceResult - Given a source type \arg Ty and an LLVM type
/// to coerce to, chose the best way to pass Ty in the same place
/// that \arg CoerceTo would be passed, but while keeping the
/// emitted code as simple as possible.
///
/// FIXME: Note, this should be cleaned up to just take an enumeration of all
/// the ways we might want to pass things, instead of constructing an LLVM
/// type. This makes this code more explicit, and it makes it clearer that we
/// are also doing this for correctness in the case of passing scalar types.
ABIArgInfo getCoerceResult(QualType Ty,
const llvm::Type *CoerceTo,
ASTContext &Context) const;
/// getIndirectResult - Give a source type \arg Ty, return a suitable result
/// such that the argument will be passed in memory.
ABIArgInfo getIndirectResult(QualType Ty,
ASTContext &Context) const;
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
ABIArgInfo classifyArgumentType(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &VMContext,
unsigned &neededInt,
unsigned &neededSSE) const;
public:
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const;
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
};
}
X86_64ABIInfo::Class X86_64ABIInfo::merge(Class Accum,
Class Field) const {
// AMD64-ABI 3.2.3p2: Rule 4. Each field of an object is
// classified recursively so that always two fields are
// considered. The resulting class is calculated according to
// the classes of the fields in the eightbyte:
//
// (a) If both classes are equal, this is the resulting class.
//
// (b) If one of the classes is NO_CLASS, the resulting class is
// the other class.
//
// (c) If one of the classes is MEMORY, the result is the MEMORY
// class.
//
// (d) If one of the classes is INTEGER, the result is the
// INTEGER.
//
// (e) If one of the classes is X87, X87UP, COMPLEX_X87 class,
// MEMORY is used as class.
//
// (f) Otherwise class SSE is used.
// Accum should never be memory (we should have returned) or
// ComplexX87 (because this cannot be passed in a structure).
assert((Accum != Memory && Accum != ComplexX87) &&
"Invalid accumulated classification during merge.");
if (Accum == Field || Field == NoClass)
return Accum;
else if (Field == Memory)
return Memory;
else if (Accum == NoClass)
return Field;
else if (Accum == Integer || Field == Integer)
return Integer;
else if (Field == X87 || Field == X87Up || Field == ComplexX87 ||
Accum == X87 || Accum == X87Up)
return Memory;
else
return SSE;
}
void X86_64ABIInfo::classify(QualType Ty,
ASTContext &Context,
uint64_t OffsetBase,
Class &Lo, Class &Hi) const {
// FIXME: This code can be simplified by introducing a simple value class for
// Class pairs with appropriate constructor methods for the various
// situations.
// FIXME: Some of the split computations are wrong; unaligned vectors
// shouldn't be passed in registers for example, so there is no chance they
// can straddle an eightbyte. Verify & simplify.
Lo = Hi = NoClass;
Class &Current = OffsetBase < 64 ? Lo : Hi;
Current = Memory;
if (const BuiltinType *BT = Ty->getAs<BuiltinType>()) {
BuiltinType::Kind k = BT->getKind();
if (k == BuiltinType::Void) {
Current = NoClass;
} else if (k == BuiltinType::Int128 || k == BuiltinType::UInt128) {
Lo = Integer;
Hi = Integer;
} else if (k >= BuiltinType::Bool && k <= BuiltinType::LongLong) {
Current = Integer;
} else if (k == BuiltinType::Float || k == BuiltinType::Double) {
Current = SSE;
} else if (k == BuiltinType::LongDouble) {
Lo = X87;
Hi = X87Up;
}
// FIXME: _Decimal32 and _Decimal64 are SSE.
// FIXME: _float128 and _Decimal128 are (SSE, SSEUp).
} else if (const EnumType *ET = Ty->getAs<EnumType>()) {
// Classify the underlying integer type.
classify(ET->getDecl()->getIntegerType(), Context, OffsetBase, Lo, Hi);
} else if (Ty->hasPointerRepresentation()) {
Current = Integer;
} else if (const VectorType *VT = Ty->getAs<VectorType>()) {
uint64_t Size = Context.getTypeSize(VT);
if (Size == 32) {
// gcc passes all <4 x char>, <2 x short>, <1 x int>, <1 x
// float> as integer.
Current = Integer;
// If this type crosses an eightbyte boundary, it should be
// split.
uint64_t EB_Real = (OffsetBase) / 64;
uint64_t EB_Imag = (OffsetBase + Size - 1) / 64;
if (EB_Real != EB_Imag)
Hi = Lo;
} else if (Size == 64) {
// gcc passes <1 x double> in memory. :(
if (VT->getElementType()->isSpecificBuiltinType(BuiltinType::Double))
return;
// gcc passes <1 x long long> as INTEGER.
if (VT->getElementType()->isSpecificBuiltinType(BuiltinType::LongLong))
Current = Integer;
else
Current = SSE;
// If this type crosses an eightbyte boundary, it should be
// split.
if (OffsetBase && OffsetBase != 64)
Hi = Lo;
} else if (Size == 128) {
Lo = SSE;
Hi = SSEUp;
}
} else if (const ComplexType *CT = Ty->getAs<ComplexType>()) {
QualType ET = Context.getCanonicalType(CT->getElementType());
uint64_t Size = Context.getTypeSize(Ty);
if (ET->isIntegralType()) {
if (Size <= 64)
Current = Integer;
else if (Size <= 128)
Lo = Hi = Integer;
} else if (ET == Context.FloatTy)
Current = SSE;
else if (ET == Context.DoubleTy)
Lo = Hi = SSE;
else if (ET == Context.LongDoubleTy)
Current = ComplexX87;
// If this complex type crosses an eightbyte boundary then it
// should be split.
uint64_t EB_Real = (OffsetBase) / 64;
uint64_t EB_Imag = (OffsetBase + Context.getTypeSize(ET)) / 64;
if (Hi == NoClass && EB_Real != EB_Imag)
Hi = Lo;
} else if (const ConstantArrayType *AT = Context.getAsConstantArrayType(Ty)) {
// Arrays are treated like structures.
uint64_t Size = Context.getTypeSize(Ty);
// AMD64-ABI 3.2.3p2: Rule 1. If the size of an object is larger
// than two eightbytes, ..., it has class MEMORY.
if (Size > 128)
return;
// AMD64-ABI 3.2.3p2: Rule 1. If ..., or it contains unaligned
// fields, it has class MEMORY.
//
// Only need to check alignment of array base.
if (OffsetBase % Context.getTypeAlign(AT->getElementType()))
return;
// Otherwise implement simplified merge. We could be smarter about
// this, but it isn't worth it and would be harder to verify.
Current = NoClass;
uint64_t EltSize = Context.getTypeSize(AT->getElementType());
uint64_t ArraySize = AT->getSize().getZExtValue();
for (uint64_t i=0, Offset=OffsetBase; i<ArraySize; ++i, Offset += EltSize) {
Class FieldLo, FieldHi;
classify(AT->getElementType(), Context, Offset, FieldLo, FieldHi);
Lo = merge(Lo, FieldLo);
Hi = merge(Hi, FieldHi);
if (Lo == Memory || Hi == Memory)
break;
}
// Do post merger cleanup (see below). Only case we worry about is Memory.
if (Hi == Memory)
Lo = Memory;
assert((Hi != SSEUp || Lo == SSE) && "Invalid SSEUp array classification.");
} else if (const RecordType *RT = Ty->getAs<RecordType>()) {
uint64_t Size = Context.getTypeSize(Ty);
// AMD64-ABI 3.2.3p2: Rule 1. If the size of an object is larger
// than two eightbytes, ..., it has class MEMORY.
if (Size > 128)
return;
// AMD64-ABI 3.2.3p2: Rule 2. If a C++ object has either a non-trivial
// copy constructor or a non-trivial destructor, it is passed by invisible
// reference.
if (hasNonTrivialDestructorOrCopyConstructor(RT))
return;
const RecordDecl *RD = RT->getDecl();
// Assume variable sized types are passed in memory.
if (RD->hasFlexibleArrayMember())
return;
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
// Reset Lo class, this will be recomputed.
Current = NoClass;
unsigned idx = 0;
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i, ++idx) {
uint64_t Offset = OffsetBase + Layout.getFieldOffset(idx);
bool BitField = i->isBitField();
// AMD64-ABI 3.2.3p2: Rule 1. If ..., or it contains unaligned
// fields, it has class MEMORY.
//
// Note, skip this test for bit-fields, see below.
if (!BitField && Offset % Context.getTypeAlign(i->getType())) {
Lo = Memory;
return;
}
// Classify this field.
//
// AMD64-ABI 3.2.3p2: Rule 3. If the size of the aggregate
// exceeds a single eightbyte, each is classified
// separately. Each eightbyte gets initialized to class
// NO_CLASS.
Class FieldLo, FieldHi;
// Bit-fields require special handling, they do not force the
// structure to be passed in memory even if unaligned, and
// therefore they can straddle an eightbyte.
if (BitField) {
// Ignore padding bit-fields.
if (i->isUnnamedBitfield())
continue;
uint64_t Offset = OffsetBase + Layout.getFieldOffset(idx);
uint64_t Size = i->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
uint64_t EB_Lo = Offset / 64;
uint64_t EB_Hi = (Offset + Size - 1) / 64;
FieldLo = FieldHi = NoClass;
if (EB_Lo) {
assert(EB_Hi == EB_Lo && "Invalid classification, type > 16 bytes.");
FieldLo = NoClass;
FieldHi = Integer;
} else {
FieldLo = Integer;
FieldHi = EB_Hi ? Integer : NoClass;
}
} else
classify(i->getType(), Context, Offset, FieldLo, FieldHi);
Lo = merge(Lo, FieldLo);
Hi = merge(Hi, FieldHi);
if (Lo == Memory || Hi == Memory)
break;
}
// AMD64-ABI 3.2.3p2: Rule 5. Then a post merger cleanup is done:
//
// (a) If one of the classes is MEMORY, the whole argument is
// passed in memory.
//
// (b) If SSEUP is not preceeded by SSE, it is converted to SSE.
// The first of these conditions is guaranteed by how we implement
// the merge (just bail).
//
// The second condition occurs in the case of unions; for example
// union { _Complex double; unsigned; }.
if (Hi == Memory)
Lo = Memory;
if (Hi == SSEUp && Lo != SSE)
Hi = SSE;
}
}
ABIArgInfo X86_64ABIInfo::getCoerceResult(QualType Ty,
const llvm::Type *CoerceTo,
ASTContext &Context) const {
if (CoerceTo == llvm::Type::getInt64Ty(CoerceTo->getContext())) {
// Integer and pointer types will end up in a general purpose
// register.
if (Ty->isIntegralType() || Ty->hasPointerRepresentation())
return (Ty->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
} else if (CoerceTo == llvm::Type::getDoubleTy(CoerceTo->getContext())) {
// FIXME: It would probably be better to make CGFunctionInfo only map using
// canonical types than to canonize here.
QualType CTy = Context.getCanonicalType(Ty);
// Float and double end up in a single SSE reg.
if (CTy == Context.FloatTy || CTy == Context.DoubleTy)
return ABIArgInfo::getDirect();
}
return ABIArgInfo::getCoerce(CoerceTo);
}
ABIArgInfo X86_64ABIInfo::getIndirectResult(QualType Ty,
ASTContext &Context) const {
// If this is a scalar LLVM value then assume LLVM will pass it in the right
// place naturally.
if (!CodeGenFunction::hasAggregateLLVMType(Ty))
return (Ty->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
bool ByVal = !isRecordWithNonTrivialDestructorOrCopyConstructor(Ty);
// FIXME: Set alignment correctly.
return ABIArgInfo::getIndirect(0, ByVal);
}
ABIArgInfo X86_64ABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
// AMD64-ABI 3.2.3p4: Rule 1. Classify the return type with the
// classification algorithm.
X86_64ABIInfo::Class Lo, Hi;
classify(RetTy, Context, 0, Lo, Hi);
// Check some invariants.
assert((Hi != Memory || Lo == Memory) && "Invalid memory classification.");
assert((Lo != NoClass || Hi == NoClass) && "Invalid null classification.");
assert((Hi != SSEUp || Lo == SSE) && "Invalid SSEUp classification.");
const llvm::Type *ResType = 0;
switch (Lo) {
case NoClass:
return ABIArgInfo::getIgnore();
case SSEUp:
case X87Up:
assert(0 && "Invalid classification for lo word.");
// AMD64-ABI 3.2.3p4: Rule 2. Types of class memory are returned via
// hidden argument.
case Memory:
return getIndirectResult(RetTy, Context);
// AMD64-ABI 3.2.3p4: Rule 3. If the class is INTEGER, the next
// available register of the sequence %rax, %rdx is used.
case Integer:
ResType = llvm::Type::getInt64Ty(VMContext); break;
// AMD64-ABI 3.2.3p4: Rule 4. If the class is SSE, the next
// available SSE register of the sequence %xmm0, %xmm1 is used.
case SSE:
ResType = llvm::Type::getDoubleTy(VMContext); break;
// AMD64-ABI 3.2.3p4: Rule 6. If the class is X87, the value is
// returned on the X87 stack in %st0 as 80-bit x87 number.
case X87:
ResType = llvm::Type::getX86_FP80Ty(VMContext); break;
// AMD64-ABI 3.2.3p4: Rule 8. If the class is COMPLEX_X87, the real
// part of the value is returned in %st0 and the imaginary part in
// %st1.
case ComplexX87:
assert(Hi == ComplexX87 && "Unexpected ComplexX87 classification.");
ResType = llvm::StructType::get(VMContext, llvm::Type::getX86_FP80Ty(VMContext),
llvm::Type::getX86_FP80Ty(VMContext),
NULL);
break;
}
switch (Hi) {
// Memory was handled previously and X87 should
// never occur as a hi class.
case Memory:
case X87:
assert(0 && "Invalid classification for hi word.");
case ComplexX87: // Previously handled.
case NoClass: break;
case Integer:
ResType = llvm::StructType::get(VMContext, ResType,
llvm::Type::getInt64Ty(VMContext), NULL);
break;
case SSE:
ResType = llvm::StructType::get(VMContext, ResType,
llvm::Type::getDoubleTy(VMContext), NULL);
break;
// AMD64-ABI 3.2.3p4: Rule 5. If the class is SSEUP, the eightbyte
// is passed in the upper half of the last used SSE register.
//
// SSEUP should always be preceeded by SSE, just widen.
case SSEUp:
assert(Lo == SSE && "Unexpected SSEUp classification.");
ResType = llvm::VectorType::get(llvm::Type::getDoubleTy(VMContext), 2);
break;
// AMD64-ABI 3.2.3p4: Rule 7. If the class is X87UP, the value is
// returned together with the previous X87 value in %st0.
case X87Up:
// If X87Up is preceeded by X87, we don't need to do
// anything. However, in some cases with unions it may not be
// preceeded by X87. In such situations we follow gcc and pass the
// extra bits in an SSE reg.
if (Lo != X87)
ResType = llvm::StructType::get(VMContext, ResType,
llvm::Type::getDoubleTy(VMContext), NULL);
break;
}
return getCoerceResult(RetTy, ResType, Context);
}
ABIArgInfo X86_64ABIInfo::classifyArgumentType(QualType Ty, ASTContext &Context,
llvm::LLVMContext &VMContext,
unsigned &neededInt,
unsigned &neededSSE) const {
X86_64ABIInfo::Class Lo, Hi;
classify(Ty, Context, 0, Lo, Hi);
// Check some invariants.
// FIXME: Enforce these by construction.
assert((Hi != Memory || Lo == Memory) && "Invalid memory classification.");
assert((Lo != NoClass || Hi == NoClass) && "Invalid null classification.");
assert((Hi != SSEUp || Lo == SSE) && "Invalid SSEUp classification.");
neededInt = 0;
neededSSE = 0;
const llvm::Type *ResType = 0;
switch (Lo) {
case NoClass:
return ABIArgInfo::getIgnore();
// AMD64-ABI 3.2.3p3: Rule 1. If the class is MEMORY, pass the argument
// on the stack.
case Memory:
// AMD64-ABI 3.2.3p3: Rule 5. If the class is X87, X87UP or
// COMPLEX_X87, it is passed in memory.
case X87:
case ComplexX87:
return getIndirectResult(Ty, Context);
case SSEUp:
case X87Up:
assert(0 && "Invalid classification for lo word.");
// AMD64-ABI 3.2.3p3: Rule 2. If the class is INTEGER, the next
// available register of the sequence %rdi, %rsi, %rdx, %rcx, %r8
// and %r9 is used.
case Integer:
++neededInt;
ResType = llvm::Type::getInt64Ty(VMContext);
break;
// AMD64-ABI 3.2.3p3: Rule 3. If the class is SSE, the next
// available SSE register is used, the registers are taken in the
// order from %xmm0 to %xmm7.
case SSE:
++neededSSE;
ResType = llvm::Type::getDoubleTy(VMContext);
break;
}
switch (Hi) {
// Memory was handled previously, ComplexX87 and X87 should
// never occur as hi classes, and X87Up must be preceed by X87,
// which is passed in memory.
case Memory:
case X87:
case ComplexX87:
assert(0 && "Invalid classification for hi word.");
break;
case NoClass: break;
case Integer:
ResType = llvm::StructType::get(VMContext, ResType,
llvm::Type::getInt64Ty(VMContext), NULL);
++neededInt;
break;
// X87Up generally doesn't occur here (long double is passed in
// memory), except in situations involving unions.
case X87Up:
case SSE:
ResType = llvm::StructType::get(VMContext, ResType,
llvm::Type::getDoubleTy(VMContext), NULL);
++neededSSE;
break;
// AMD64-ABI 3.2.3p3: Rule 4. If the class is SSEUP, the
// eightbyte is passed in the upper half of the last used SSE
// register.
case SSEUp:
assert(Lo == SSE && "Unexpected SSEUp classification.");
ResType = llvm::VectorType::get(llvm::Type::getDoubleTy(VMContext), 2);
break;
}
return getCoerceResult(Ty, ResType, Context);
}
void X86_64ABIInfo::computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(),
Context, VMContext);
// Keep track of the number of assigned registers.
unsigned freeIntRegs = 6, freeSSERegs = 8;
// If the return value is indirect, then the hidden argument is consuming one
// integer register.
if (FI.getReturnInfo().isIndirect())
--freeIntRegs;
// AMD64-ABI 3.2.3p3: Once arguments are classified, the registers
// get assigned (in left-to-right order) for passing as follows...
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it) {
unsigned neededInt, neededSSE;
it->info = classifyArgumentType(it->type, Context, VMContext,
neededInt, neededSSE);
// AMD64-ABI 3.2.3p3: If there are no registers available for any
// eightbyte of an argument, the whole argument is passed on the
// stack. If registers have already been assigned for some
// eightbytes of such an argument, the assignments get reverted.
if (freeIntRegs >= neededInt && freeSSERegs >= neededSSE) {
freeIntRegs -= neededInt;
freeSSERegs -= neededSSE;
} else {
it->info = getIndirectResult(it->type, Context);
}
}
}
static llvm::Value *EmitVAArgFromMemory(llvm::Value *VAListAddr,
QualType Ty,
CodeGenFunction &CGF) {
llvm::Value *overflow_arg_area_p =
CGF.Builder.CreateStructGEP(VAListAddr, 2, "overflow_arg_area_p");
llvm::Value *overflow_arg_area =
CGF.Builder.CreateLoad(overflow_arg_area_p, "overflow_arg_area");
// AMD64-ABI 3.5.7p5: Step 7. Align l->overflow_arg_area upwards to a 16
// byte boundary if alignment needed by type exceeds 8 byte boundary.
uint64_t Align = CGF.getContext().getTypeAlign(Ty) / 8;
if (Align > 8) {
// Note that we follow the ABI & gcc here, even though the type
// could in theory have an alignment greater than 16. This case
// shouldn't ever matter in practice.
// overflow_arg_area = (overflow_arg_area + 15) & ~15;
llvm::Value *Offset =
llvm::ConstantInt::get(llvm::Type::getInt32Ty(CGF.getLLVMContext()), 15);
overflow_arg_area = CGF.Builder.CreateGEP(overflow_arg_area, Offset);
llvm::Value *AsInt = CGF.Builder.CreatePtrToInt(overflow_arg_area,
llvm::Type::getInt64Ty(CGF.getLLVMContext()));
llvm::Value *Mask = llvm::ConstantInt::get(
llvm::Type::getInt64Ty(CGF.getLLVMContext()), ~15LL);
overflow_arg_area =
CGF.Builder.CreateIntToPtr(CGF.Builder.CreateAnd(AsInt, Mask),
overflow_arg_area->getType(),
"overflow_arg_area.align");
}
// AMD64-ABI 3.5.7p5: Step 8. Fetch type from l->overflow_arg_area.
const llvm::Type *LTy = CGF.ConvertTypeForMem(Ty);
llvm::Value *Res =
CGF.Builder.CreateBitCast(overflow_arg_area,
llvm::PointerType::getUnqual(LTy));
// AMD64-ABI 3.5.7p5: Step 9. Set l->overflow_arg_area to:
// l->overflow_arg_area + sizeof(type).
// AMD64-ABI 3.5.7p5: Step 10. Align l->overflow_arg_area upwards to
// an 8 byte boundary.
uint64_t SizeInBytes = (CGF.getContext().getTypeSize(Ty) + 7) / 8;
llvm::Value *Offset =
llvm::ConstantInt::get(llvm::Type::getInt32Ty(CGF.getLLVMContext()),
(SizeInBytes + 7) & ~7);
overflow_arg_area = CGF.Builder.CreateGEP(overflow_arg_area, Offset,
"overflow_arg_area.next");
CGF.Builder.CreateStore(overflow_arg_area, overflow_arg_area_p);
// AMD64-ABI 3.5.7p5: Step 11. Return the fetched type.
return Res;
}
llvm::Value *X86_64ABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const {
llvm::LLVMContext &VMContext = CGF.getLLVMContext();
const llvm::Type *i32Ty = llvm::Type::getInt32Ty(VMContext);
const llvm::Type *DoubleTy = llvm::Type::getDoubleTy(VMContext);
// Assume that va_list type is correct; should be pointer to LLVM type:
// struct {
// i32 gp_offset;
// i32 fp_offset;
// i8* overflow_arg_area;
// i8* reg_save_area;
// };
unsigned neededInt, neededSSE;
ABIArgInfo AI = classifyArgumentType(Ty, CGF.getContext(), VMContext,
neededInt, neededSSE);
// AMD64-ABI 3.5.7p5: Step 1. Determine whether type may be passed
// in the registers. If not go to step 7.
if (!neededInt && !neededSSE)
return EmitVAArgFromMemory(VAListAddr, Ty, CGF);
// AMD64-ABI 3.5.7p5: Step 2. Compute num_gp to hold the number of
// general purpose registers needed to pass type and num_fp to hold
// the number of floating point registers needed.
// AMD64-ABI 3.5.7p5: Step 3. Verify whether arguments fit into
// registers. In the case: l->gp_offset > 48 - num_gp * 8 or
// l->fp_offset > 304 - num_fp * 16 go to step 7.
//
// NOTE: 304 is a typo, there are (6 * 8 + 8 * 16) = 176 bytes of
// register save space).
llvm::Value *InRegs = 0;
llvm::Value *gp_offset_p = 0, *gp_offset = 0;
llvm::Value *fp_offset_p = 0, *fp_offset = 0;
if (neededInt) {
gp_offset_p = CGF.Builder.CreateStructGEP(VAListAddr, 0, "gp_offset_p");
gp_offset = CGF.Builder.CreateLoad(gp_offset_p, "gp_offset");
InRegs =
CGF.Builder.CreateICmpULE(gp_offset,
llvm::ConstantInt::get(i32Ty,
48 - neededInt * 8),
"fits_in_gp");
}
if (neededSSE) {
fp_offset_p = CGF.Builder.CreateStructGEP(VAListAddr, 1, "fp_offset_p");
fp_offset = CGF.Builder.CreateLoad(fp_offset_p, "fp_offset");
llvm::Value *FitsInFP =
CGF.Builder.CreateICmpULE(fp_offset,
llvm::ConstantInt::get(i32Ty,
176 - neededSSE * 16),
"fits_in_fp");
InRegs = InRegs ? CGF.Builder.CreateAnd(InRegs, FitsInFP) : FitsInFP;
}
llvm::BasicBlock *InRegBlock = CGF.createBasicBlock("vaarg.in_reg");
llvm::BasicBlock *InMemBlock = CGF.createBasicBlock("vaarg.in_mem");
llvm::BasicBlock *ContBlock = CGF.createBasicBlock("vaarg.end");
CGF.Builder.CreateCondBr(InRegs, InRegBlock, InMemBlock);
// Emit code to load the value if it was passed in registers.
CGF.EmitBlock(InRegBlock);
// AMD64-ABI 3.5.7p5: Step 4. Fetch type from l->reg_save_area with
// an offset of l->gp_offset and/or l->fp_offset. This may require
// copying to a temporary location in case the parameter is passed
// in different register classes or requires an alignment greater
// than 8 for general purpose registers and 16 for XMM registers.
//
// FIXME: This really results in shameful code when we end up needing to
// collect arguments from different places; often what should result in a
// simple assembling of a structure from scattered addresses has many more
// loads than necessary. Can we clean this up?
const llvm::Type *LTy = CGF.ConvertTypeForMem(Ty);
llvm::Value *RegAddr =
CGF.Builder.CreateLoad(CGF.Builder.CreateStructGEP(VAListAddr, 3),
"reg_save_area");
if (neededInt && neededSSE) {
// FIXME: Cleanup.
assert(AI.isCoerce() && "Unexpected ABI info for mixed regs");
const llvm::StructType *ST = cast<llvm::StructType>(AI.getCoerceToType());
llvm::Value *Tmp = CGF.CreateTempAlloca(ST);
assert(ST->getNumElements() == 2 && "Unexpected ABI info for mixed regs");
const llvm::Type *TyLo = ST->getElementType(0);
const llvm::Type *TyHi = ST->getElementType(1);
assert((TyLo->isFloatingPoint() ^ TyHi->isFloatingPoint()) &&
"Unexpected ABI info for mixed regs");
const llvm::Type *PTyLo = llvm::PointerType::getUnqual(TyLo);
const llvm::Type *PTyHi = llvm::PointerType::getUnqual(TyHi);
llvm::Value *GPAddr = CGF.Builder.CreateGEP(RegAddr, gp_offset);
llvm::Value *FPAddr = CGF.Builder.CreateGEP(RegAddr, fp_offset);
llvm::Value *RegLoAddr = TyLo->isFloatingPoint() ? FPAddr : GPAddr;
llvm::Value *RegHiAddr = TyLo->isFloatingPoint() ? GPAddr : FPAddr;
llvm::Value *V =
CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegLoAddr, PTyLo));
CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 0));
V = CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegHiAddr, PTyHi));
CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 1));
RegAddr = CGF.Builder.CreateBitCast(Tmp,
llvm::PointerType::getUnqual(LTy));
} else if (neededInt) {
RegAddr = CGF.Builder.CreateGEP(RegAddr, gp_offset);
RegAddr = CGF.Builder.CreateBitCast(RegAddr,
llvm::PointerType::getUnqual(LTy));
} else {
if (neededSSE == 1) {
RegAddr = CGF.Builder.CreateGEP(RegAddr, fp_offset);
RegAddr = CGF.Builder.CreateBitCast(RegAddr,
llvm::PointerType::getUnqual(LTy));
} else {
assert(neededSSE == 2 && "Invalid number of needed registers!");
// SSE registers are spaced 16 bytes apart in the register save
// area, we need to collect the two eightbytes together.
llvm::Value *RegAddrLo = CGF.Builder.CreateGEP(RegAddr, fp_offset);
llvm::Value *RegAddrHi =
CGF.Builder.CreateGEP(RegAddrLo,
llvm::ConstantInt::get(i32Ty, 16));
const llvm::Type *DblPtrTy =
llvm::PointerType::getUnqual(DoubleTy);
const llvm::StructType *ST = llvm::StructType::get(VMContext, DoubleTy,
DoubleTy, NULL);
llvm::Value *V, *Tmp = CGF.CreateTempAlloca(ST);
V = CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegAddrLo,
DblPtrTy));
CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 0));
V = CGF.Builder.CreateLoad(CGF.Builder.CreateBitCast(RegAddrHi,
DblPtrTy));
CGF.Builder.CreateStore(V, CGF.Builder.CreateStructGEP(Tmp, 1));
RegAddr = CGF.Builder.CreateBitCast(Tmp,
llvm::PointerType::getUnqual(LTy));
}
}
// AMD64-ABI 3.5.7p5: Step 5. Set:
// l->gp_offset = l->gp_offset + num_gp * 8
// l->fp_offset = l->fp_offset + num_fp * 16.
if (neededInt) {
llvm::Value *Offset = llvm::ConstantInt::get(i32Ty, neededInt * 8);
CGF.Builder.CreateStore(CGF.Builder.CreateAdd(gp_offset, Offset),
gp_offset_p);
}
if (neededSSE) {
llvm::Value *Offset = llvm::ConstantInt::get(i32Ty, neededSSE * 16);
CGF.Builder.CreateStore(CGF.Builder.CreateAdd(fp_offset, Offset),
fp_offset_p);
}
CGF.EmitBranch(ContBlock);
// Emit code to load the value if it was passed in memory.
CGF.EmitBlock(InMemBlock);
llvm::Value *MemAddr = EmitVAArgFromMemory(VAListAddr, Ty, CGF);
// Return the appropriate result.
CGF.EmitBlock(ContBlock);
llvm::PHINode *ResAddr = CGF.Builder.CreatePHI(RegAddr->getType(),
"vaarg.addr");
ResAddr->reserveOperandSpace(2);
ResAddr->addIncoming(RegAddr, InRegBlock);
ResAddr->addIncoming(MemAddr, InMemBlock);
return ResAddr;
}
// PIC16 ABI Implementation
namespace {
class PIC16ABIInfo : public ABIInfo {
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
ABIArgInfo classifyArgumentType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), Context,
VMContext);
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it)
it->info = classifyArgumentType(it->type, Context, VMContext);
}
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
};
}
ABIArgInfo PIC16ABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (RetTy->isVoidType()) {
return ABIArgInfo::getIgnore();
} else {
return ABIArgInfo::getDirect();
}
}
ABIArgInfo PIC16ABIInfo::classifyArgumentType(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
return ABIArgInfo::getDirect();
}
llvm::Value *PIC16ABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const {
return 0;
}
// ARM ABI Implementation
namespace {
class ARMABIInfo : public ABIInfo {
public:
enum ABIKind {
APCS = 0,
AAPCS = 1,
AAPCS_VFP
};
private:
ABIKind Kind;
public:
ARMABIInfo(ABIKind _Kind) : Kind(_Kind) {}
private:
ABIKind getABIKind() const { return Kind; }
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMCOntext) const;
ABIArgInfo classifyArgumentType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const;
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const;
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
};
}
void ARMABIInfo::computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), Context,
VMContext);
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it) {
it->info = classifyArgumentType(it->type, Context, VMContext);
}
// ARM always overrides the calling convention.
switch (getABIKind()) {
case APCS:
FI.setEffectiveCallingConvention(llvm::CallingConv::ARM_APCS);
break;
case AAPCS:
FI.setEffectiveCallingConvention(llvm::CallingConv::ARM_AAPCS);
break;
case AAPCS_VFP:
FI.setEffectiveCallingConvention(llvm::CallingConv::ARM_AAPCS_VFP);
break;
}
}
ABIArgInfo ARMABIInfo::classifyArgumentType(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (!CodeGenFunction::hasAggregateLLVMType(Ty))
return (Ty->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
// Ignore empty records.
if (isEmptyRecord(Context, Ty, true))
return ABIArgInfo::getIgnore();
// FIXME: This is kind of nasty... but there isn't much choice because the ARM
// backend doesn't support byval.
// FIXME: This doesn't handle alignment > 64 bits.
const llvm::Type* ElemTy;
unsigned SizeRegs;
if (Context.getTypeAlign(Ty) > 32) {
ElemTy = llvm::Type::getInt64Ty(VMContext);
SizeRegs = (Context.getTypeSize(Ty) + 63) / 64;
} else {
ElemTy = llvm::Type::getInt32Ty(VMContext);
SizeRegs = (Context.getTypeSize(Ty) + 31) / 32;
}
std::vector<const llvm::Type*> LLVMFields;
LLVMFields.push_back(llvm::ArrayType::get(ElemTy, SizeRegs));
const llvm::Type* STy = llvm::StructType::get(VMContext, LLVMFields, true);
return ABIArgInfo::getCoerce(STy);
}
static bool isIntegerLikeType(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &VMContext) {
// APCS, C Language Calling Conventions, Non-Simple Return Values: A structure
// is called integer-like if its size is less than or equal to one word, and
// the offset of each of its addressable sub-fields is zero.
uint64_t Size = Context.getTypeSize(Ty);
// Check that the type fits in a word.
if (Size > 32)
return false;
// FIXME: Handle vector types!
if (Ty->isVectorType())
return false;
// Float types are never treated as "integer like".
if (Ty->isRealFloatingType())
return false;
// If this is a builtin or pointer type then it is ok.
if (Ty->getAs<BuiltinType>() || Ty->isPointerType())
return true;
// Complex types "should" be ok by the definition above, but they are not.
if (Ty->isAnyComplexType())
return false;
// Single element and zero sized arrays should be allowed, by the definition
// above, but they are not.
// Otherwise, it must be a record type.
const RecordType *RT = Ty->getAs<RecordType>();
if (!RT) return false;
// Ignore records with flexible arrays.
const RecordDecl *RD = RT->getDecl();
if (RD->hasFlexibleArrayMember())
return false;
// Check that all sub-fields are at offset 0, and are themselves "integer
// like".
const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
bool HadField = false;
unsigned idx = 0;
for (RecordDecl::field_iterator i = RD->field_begin(), e = RD->field_end();
i != e; ++i, ++idx) {
const FieldDecl *FD = *i;
// Check if this field is at offset 0.
uint64_t Offset = Layout.getFieldOffset(idx);
if (Offset != 0) {
// Allow padding bit-fields, but only if they are all at the end of the
// structure (despite the wording above, this matches gcc).
if (FD->isBitField() &&
!FD->getBitWidth()->EvaluateAsInt(Context).getZExtValue()) {
for (; i != e; ++i)
if (!i->isBitField() ||
i->getBitWidth()->EvaluateAsInt(Context).getZExtValue())
return false;
// All remaining fields are padding, allow this.
return true;
}
return false;
}
if (!isIntegerLikeType(FD->getType(), Context, VMContext))
return false;
// Only allow at most one field in a structure. Again this doesn't match the
// wording above, but follows gcc.
if (!RD->isUnion()) {
if (HadField)
return false;
HadField = true;
}
}
return true;
}
ABIArgInfo ARMABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (RetTy->isVoidType())
return ABIArgInfo::getIgnore();
if (!CodeGenFunction::hasAggregateLLVMType(RetTy))
return (RetTy->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
// Are we following APCS?
if (getABIKind() == APCS) {
if (isEmptyRecord(Context, RetTy, false))
return ABIArgInfo::getIgnore();
// Integer like structures are returned in r0.
if (isIntegerLikeType(RetTy, Context, VMContext)) {
// Return in the smallest viable integer type.
uint64_t Size = Context.getTypeSize(RetTy);
if (Size <= 8)
return ABIArgInfo::getCoerce(llvm::Type::getInt8Ty(VMContext));
if (Size <= 16)
return ABIArgInfo::getCoerce(llvm::Type::getInt16Ty(VMContext));
return ABIArgInfo::getCoerce(llvm::Type::getInt32Ty(VMContext));
}
// Otherwise return in memory.
return ABIArgInfo::getIndirect(0);
}
// Otherwise this is an AAPCS variant.
if (isEmptyRecord(Context, RetTy, true))
return ABIArgInfo::getIgnore();
// Aggregates <= 4 bytes are returned in r0; other aggregates
// are returned indirectly.
uint64_t Size = Context.getTypeSize(RetTy);
if (Size <= 32) {
// Return in the smallest viable integer type.
if (Size <= 8)
return ABIArgInfo::getCoerce(llvm::Type::getInt8Ty(VMContext));
if (Size <= 16)
return ABIArgInfo::getCoerce(llvm::Type::getInt16Ty(VMContext));
return ABIArgInfo::getCoerce(llvm::Type::getInt32Ty(VMContext));
}
return ABIArgInfo::getIndirect(0);
}
llvm::Value *ARMABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const {
// FIXME: Need to handle alignment
const llvm::Type *BP =
llvm::PointerType::getUnqual(llvm::Type::getInt8Ty(CGF.getLLVMContext()));
const llvm::Type *BPP = llvm::PointerType::getUnqual(BP);
CGBuilderTy &Builder = CGF.Builder;
llvm::Value *VAListAddrAsBPP = Builder.CreateBitCast(VAListAddr, BPP,
"ap");
llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP, "ap.cur");
llvm::Type *PTy =
llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
llvm::Value *AddrTyped = Builder.CreateBitCast(Addr, PTy);
uint64_t Offset =
llvm::RoundUpToAlignment(CGF.getContext().getTypeSize(Ty) / 8, 4);
llvm::Value *NextAddr =
Builder.CreateGEP(Addr, llvm::ConstantInt::get(
llvm::Type::getInt32Ty(CGF.getLLVMContext()), Offset),
"ap.next");
Builder.CreateStore(NextAddr, VAListAddrAsBPP);
return AddrTyped;
}
ABIArgInfo DefaultABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (RetTy->isVoidType()) {
return ABIArgInfo::getIgnore();
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
return ABIArgInfo::getIndirect(0);
} else {
return (RetTy->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
}
// SystemZ ABI Implementation
namespace {
class SystemZABIInfo : public ABIInfo {
bool isPromotableIntegerType(QualType Ty) const;
ABIArgInfo classifyReturnType(QualType RetTy, ASTContext &Context,
llvm::LLVMContext &VMContext) const;
ABIArgInfo classifyArgumentType(QualType RetTy, ASTContext &Context,
llvm::LLVMContext &VMContext) const;
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context,
llvm::LLVMContext &VMContext) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(),
Context, VMContext);
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it)
it->info = classifyArgumentType(it->type, Context, VMContext);
}
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
};
}
bool SystemZABIInfo::isPromotableIntegerType(QualType Ty) const {
// SystemZ ABI requires all 8, 16 and 32 bit quantities to be extended.
if (const BuiltinType *BT = Ty->getAs<BuiltinType>())
switch (BT->getKind()) {
case BuiltinType::Bool:
case BuiltinType::Char_S:
case BuiltinType::Char_U:
case BuiltinType::SChar:
case BuiltinType::UChar:
case BuiltinType::Short:
case BuiltinType::UShort:
case BuiltinType::Int:
case BuiltinType::UInt:
return true;
default:
return false;
}
return false;
}
llvm::Value *SystemZABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const {
// FIXME: Implement
return 0;
}
ABIArgInfo SystemZABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (RetTy->isVoidType()) {
return ABIArgInfo::getIgnore();
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
return ABIArgInfo::getIndirect(0);
} else {
return (isPromotableIntegerType(RetTy) ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
}
ABIArgInfo SystemZABIInfo::classifyArgumentType(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (CodeGenFunction::hasAggregateLLVMType(Ty)) {
return ABIArgInfo::getIndirect(0);
} else {
return (isPromotableIntegerType(Ty) ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
}
ABIArgInfo DefaultABIInfo::classifyArgumentType(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &VMContext) const {
if (CodeGenFunction::hasAggregateLLVMType(Ty)) {
return ABIArgInfo::getIndirect(0);
} else {
return (Ty->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
}
llvm::Value *DefaultABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const {
return 0;
}
const ABIInfo &CodeGenTypes::getABIInfo() const {
if (TheABIInfo)
return *TheABIInfo;
// For now we just cache the ABIInfo in CodeGenTypes and don't free it.
const llvm::Triple &Triple(getContext().Target.getTriple());
switch (Triple.getArch()) {
default:
return *(TheABIInfo = new DefaultABIInfo);
case llvm::Triple::arm:
case llvm::Triple::thumb:
// FIXME: We want to know the float calling convention as well.
if (strcmp(getContext().Target.getABI(), "apcs-gnu") == 0)
return *(TheABIInfo = new ARMABIInfo(ARMABIInfo::APCS));
return *(TheABIInfo = new ARMABIInfo(ARMABIInfo::AAPCS));
case llvm::Triple::pic16:
return *(TheABIInfo = new PIC16ABIInfo());
case llvm::Triple::systemz:
return *(TheABIInfo = new SystemZABIInfo());
case llvm::Triple::x86:
if (Triple.getOS() == llvm::Triple::Darwin)
return *(TheABIInfo = new X86_32ABIInfo(Context, true, true));
switch (Triple.getOS()) {
case llvm::Triple::Cygwin:
case llvm::Triple::DragonFly:
case llvm::Triple::MinGW32:
case llvm::Triple::MinGW64:
case llvm::Triple::FreeBSD:
case llvm::Triple::OpenBSD:
return *(TheABIInfo = new X86_32ABIInfo(Context, false, true));
default:
return *(TheABIInfo = new X86_32ABIInfo(Context, false, false));
}
case llvm::Triple::x86_64:
return *(TheABIInfo = new X86_64ABIInfo());
}
}
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