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TargetInfo.cpp
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//===---- TargetInfo.cpp - Encapsulate target 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 "TargetInfo.h"
#include "ABIInfo.h"
#include "CGBlocks.h"
#include "CGCXXABI.h"
#include "CGValue.h"
#include "CodeGenFunction.h"
#include "clang/AST/RecordLayout.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "clang/CodeGen/SwiftCallingConv.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/Twine.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm> // std::sort
using namespace clang;
using namespace CodeGen;
// Helper for coercing an aggregate argument or return value into an integer
// array of the same size (including padding) and alignment. This alternate
// coercion happens only for the RenderScript ABI and can be removed after
// runtimes that rely on it are no longer supported.
//
// RenderScript assumes that the size of the argument / return value in the IR
// is the same as the size of the corresponding qualified type. This helper
// coerces the aggregate type into an array of the same size (including
// padding). This coercion is used in lieu of expansion of struct members or
// other canonical coercions that return a coerced-type of larger size.
//
// Ty - The argument / return value type
// Context - The associated ASTContext
// LLVMContext - The associated LLVMContext
static ABIArgInfo coerceToIntArray(QualType Ty,
ASTContext &Context,
llvm::LLVMContext &LLVMContext) {
// Alignment and Size are measured in bits.
const uint64_t Size = Context.getTypeSize(Ty);
const uint64_t Alignment = Context.getTypeAlign(Ty);
llvm::Type *IntType = llvm::Type::getIntNTy(LLVMContext, Alignment);
const uint64_t NumElements = (Size + Alignment - 1) / Alignment;
return ABIArgInfo::getDirect(llvm::ArrayType::get(IntType, NumElements));
}
static void AssignToArrayRange(CodeGen::CGBuilderTy &Builder,
llvm::Value *Array,
llvm::Value *Value,
unsigned FirstIndex,
unsigned LastIndex) {
// Alternatively, we could emit this as a loop in the source.
for (unsigned I = FirstIndex; I <= LastIndex; ++I) {
llvm::Value *Cell =
Builder.CreateConstInBoundsGEP1_32(Builder.getInt8Ty(), Array, I);
Builder.CreateAlignedStore(Value, Cell, CharUnits::One());
}
}
static bool isAggregateTypeForABI(QualType T) {
return !CodeGenFunction::hasScalarEvaluationKind(T) ||
T->isMemberFunctionPointerType();
}
ABIArgInfo
ABIInfo::getNaturalAlignIndirect(QualType Ty, bool ByRef, bool Realign,
llvm::Type *Padding) const {
return ABIArgInfo::getIndirect(getContext().getTypeAlignInChars(Ty),
ByRef, Realign, Padding);
}
ABIArgInfo
ABIInfo::getNaturalAlignIndirectInReg(QualType Ty, bool Realign) const {
return ABIArgInfo::getIndirectInReg(getContext().getTypeAlignInChars(Ty),
/*ByRef*/ false, Realign);
}
Address ABIInfo::EmitMSVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const {
return Address::invalid();
}
ABIInfo::~ABIInfo() {}
/// Does the given lowering require more than the given number of
/// registers when expanded?
///
/// This is intended to be the basis of a reasonable basic implementation
/// of should{Pass,Return}IndirectlyForSwift.
///
/// For most targets, a limit of four total registers is reasonable; this
/// limits the amount of code required in order to move around the value
/// in case it wasn't produced immediately prior to the call by the caller
/// (or wasn't produced in exactly the right registers) or isn't used
/// immediately within the callee. But some targets may need to further
/// limit the register count due to an inability to support that many
/// return registers.
static bool occupiesMoreThan(CodeGenTypes &cgt,
ArrayRef<llvm::Type*> scalarTypes,
unsigned maxAllRegisters) {
unsigned intCount = 0, fpCount = 0;
for (llvm::Type *type : scalarTypes) {
if (type->isPointerTy()) {
intCount++;
} else if (auto intTy = dyn_cast<llvm::IntegerType>(type)) {
auto ptrWidth = cgt.getTarget().getPointerWidth(0);
intCount += (intTy->getBitWidth() + ptrWidth - 1) / ptrWidth;
} else {
assert(type->isVectorTy() || type->isFloatingPointTy());
fpCount++;
}
}
return (intCount + fpCount > maxAllRegisters);
}
bool SwiftABIInfo::isLegalVectorTypeForSwift(CharUnits vectorSize,
llvm::Type *eltTy,
unsigned numElts) const {
// The default implementation of this assumes that the target guarantees
// 128-bit SIMD support but nothing more.
return (vectorSize.getQuantity() > 8 && vectorSize.getQuantity() <= 16);
}
static CGCXXABI::RecordArgABI getRecordArgABI(const RecordType *RT,
CGCXXABI &CXXABI) {
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
if (!RD)
return CGCXXABI::RAA_Default;
return CXXABI.getRecordArgABI(RD);
}
static CGCXXABI::RecordArgABI getRecordArgABI(QualType T,
CGCXXABI &CXXABI) {
const RecordType *RT = T->getAs<RecordType>();
if (!RT)
return CGCXXABI::RAA_Default;
return getRecordArgABI(RT, CXXABI);
}
/// Pass transparent unions as if they were the type of the first element. Sema
/// should ensure that all elements of the union have the same "machine type".
static QualType useFirstFieldIfTransparentUnion(QualType Ty) {
if (const RecordType *UT = Ty->getAsUnionType()) {
const RecordDecl *UD = UT->getDecl();
if (UD->hasAttr<TransparentUnionAttr>()) {
assert(!UD->field_empty() && "sema created an empty transparent union");
return UD->field_begin()->getType();
}
}
return Ty;
}
CGCXXABI &ABIInfo::getCXXABI() const {
return CGT.getCXXABI();
}
ASTContext &ABIInfo::getContext() const {
return CGT.getContext();
}
llvm::LLVMContext &ABIInfo::getVMContext() const {
return CGT.getLLVMContext();
}
const llvm::DataLayout &ABIInfo::getDataLayout() const {
return CGT.getDataLayout();
}
const TargetInfo &ABIInfo::getTarget() const {
return CGT.getTarget();
}
const CodeGenOptions &ABIInfo::getCodeGenOpts() const {
return CGT.getCodeGenOpts();
}
bool ABIInfo::isAndroid() const { return getTarget().getTriple().isAndroid(); }
bool ABIInfo::isHomogeneousAggregateBaseType(QualType Ty) const {
return false;
}
bool ABIInfo::isHomogeneousAggregateSmallEnough(const Type *Base,
uint64_t Members) const {
return false;
}
bool ABIInfo::shouldSignExtUnsignedType(QualType Ty) const {
return false;
}
LLVM_DUMP_METHOD void ABIArgInfo::dump() const {
raw_ostream &OS = llvm::errs();
OS << "(ABIArgInfo Kind=";
switch (TheKind) {
case Direct:
OS << "Direct Type=";
if (llvm::Type *Ty = getCoerceToType())
Ty->print(OS);
else
OS << "null";
break;
case Extend:
OS << "Extend";
break;
case Ignore:
OS << "Ignore";
break;
case InAlloca:
OS << "InAlloca Offset=" << getInAllocaFieldIndex();
break;
case Indirect:
OS << "Indirect Align=" << getIndirectAlign().getQuantity()
<< " ByVal=" << getIndirectByVal()
<< " Realign=" << getIndirectRealign();
break;
case Expand:
OS << "Expand";
break;
case CoerceAndExpand:
OS << "CoerceAndExpand Type=";
getCoerceAndExpandType()->print(OS);
break;
}
OS << ")\n";
}
// Dynamically round a pointer up to a multiple of the given alignment.
static llvm::Value *emitRoundPointerUpToAlignment(CodeGenFunction &CGF,
llvm::Value *Ptr,
CharUnits Align) {
llvm::Value *PtrAsInt = Ptr;
// OverflowArgArea = (OverflowArgArea + Align - 1) & -Align;
PtrAsInt = CGF.Builder.CreatePtrToInt(PtrAsInt, CGF.IntPtrTy);
PtrAsInt = CGF.Builder.CreateAdd(PtrAsInt,
llvm::ConstantInt::get(CGF.IntPtrTy, Align.getQuantity() - 1));
PtrAsInt = CGF.Builder.CreateAnd(PtrAsInt,
llvm::ConstantInt::get(CGF.IntPtrTy, -Align.getQuantity()));
PtrAsInt = CGF.Builder.CreateIntToPtr(PtrAsInt,
Ptr->getType(),
Ptr->getName() + ".aligned");
return PtrAsInt;
}
/// Emit va_arg for a platform using the common void* representation,
/// where arguments are simply emitted in an array of slots on the stack.
///
/// This version implements the core direct-value passing rules.
///
/// \param SlotSize - The size and alignment of a stack slot.
/// Each argument will be allocated to a multiple of this number of
/// slots, and all the slots will be aligned to this value.
/// \param AllowHigherAlign - The slot alignment is not a cap;
/// an argument type with an alignment greater than the slot size
/// will be emitted on a higher-alignment address, potentially
/// leaving one or more empty slots behind as padding. If this
/// is false, the returned address might be less-aligned than
/// DirectAlign.
static Address emitVoidPtrDirectVAArg(CodeGenFunction &CGF,
Address VAListAddr,
llvm::Type *DirectTy,
CharUnits DirectSize,
CharUnits DirectAlign,
CharUnits SlotSize,
bool AllowHigherAlign) {
// Cast the element type to i8* if necessary. Some platforms define
// va_list as a struct containing an i8* instead of just an i8*.
if (VAListAddr.getElementType() != CGF.Int8PtrTy)
VAListAddr = CGF.Builder.CreateElementBitCast(VAListAddr, CGF.Int8PtrTy);
llvm::Value *Ptr = CGF.Builder.CreateLoad(VAListAddr, "argp.cur");
// If the CC aligns values higher than the slot size, do so if needed.
Address Addr = Address::invalid();
if (AllowHigherAlign && DirectAlign > SlotSize) {
Addr = Address(emitRoundPointerUpToAlignment(CGF, Ptr, DirectAlign),
DirectAlign);
} else {
Addr = Address(Ptr, SlotSize);
}
// Advance the pointer past the argument, then store that back.
CharUnits FullDirectSize = DirectSize.alignTo(SlotSize);
llvm::Value *NextPtr =
CGF.Builder.CreateConstInBoundsByteGEP(Addr.getPointer(), FullDirectSize,
"argp.next");
CGF.Builder.CreateStore(NextPtr, VAListAddr);
// If the argument is smaller than a slot, and this is a big-endian
// target, the argument will be right-adjusted in its slot.
if (DirectSize < SlotSize && CGF.CGM.getDataLayout().isBigEndian() &&
!DirectTy->isStructTy()) {
Addr = CGF.Builder.CreateConstInBoundsByteGEP(Addr, SlotSize - DirectSize);
}
Addr = CGF.Builder.CreateElementBitCast(Addr, DirectTy);
return Addr;
}
/// Emit va_arg for a platform using the common void* representation,
/// where arguments are simply emitted in an array of slots on the stack.
///
/// \param IsIndirect - Values of this type are passed indirectly.
/// \param ValueInfo - The size and alignment of this type, generally
/// computed with getContext().getTypeInfoInChars(ValueTy).
/// \param SlotSizeAndAlign - The size and alignment of a stack slot.
/// Each argument will be allocated to a multiple of this number of
/// slots, and all the slots will be aligned to this value.
/// \param AllowHigherAlign - The slot alignment is not a cap;
/// an argument type with an alignment greater than the slot size
/// will be emitted on a higher-alignment address, potentially
/// leaving one or more empty slots behind as padding.
static Address emitVoidPtrVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType ValueTy, bool IsIndirect,
std::pair<CharUnits, CharUnits> ValueInfo,
CharUnits SlotSizeAndAlign,
bool AllowHigherAlign) {
// The size and alignment of the value that was passed directly.
CharUnits DirectSize, DirectAlign;
if (IsIndirect) {
DirectSize = CGF.getPointerSize();
DirectAlign = CGF.getPointerAlign();
} else {
DirectSize = ValueInfo.first;
DirectAlign = ValueInfo.second;
}
// Cast the address we've calculated to the right type.
llvm::Type *DirectTy = CGF.ConvertTypeForMem(ValueTy);
if (IsIndirect)
DirectTy = DirectTy->getPointerTo(0);
Address Addr = emitVoidPtrDirectVAArg(CGF, VAListAddr, DirectTy,
DirectSize, DirectAlign,
SlotSizeAndAlign,
AllowHigherAlign);
if (IsIndirect) {
Addr = Address(CGF.Builder.CreateLoad(Addr), ValueInfo.second);
}
return Addr;
}
static Address emitMergePHI(CodeGenFunction &CGF,
Address Addr1, llvm::BasicBlock *Block1,
Address Addr2, llvm::BasicBlock *Block2,
const llvm::Twine &Name = "") {
assert(Addr1.getType() == Addr2.getType());
llvm::PHINode *PHI = CGF.Builder.CreatePHI(Addr1.getType(), 2, Name);
PHI->addIncoming(Addr1.getPointer(), Block1);
PHI->addIncoming(Addr2.getPointer(), Block2);
CharUnits Align = std::min(Addr1.getAlignment(), Addr2.getAlignment());
return Address(PHI, Align);
}
TargetCodeGenInfo::~TargetCodeGenInfo() { delete Info; }
// If someone can figure out a general rule for this, that would be great.
// It's probably just doomed to be platform-dependent, though.
unsigned TargetCodeGenInfo::getSizeOfUnwindException() const {
// Verified for:
// x86-64 FreeBSD, Linux, Darwin
// x86-32 FreeBSD, Linux, Darwin
// PowerPC Linux, Darwin
// ARM Darwin (*not* EABI)
// AArch64 Linux
return 32;
}
bool TargetCodeGenInfo::isNoProtoCallVariadic(const CallArgList &args,
const FunctionNoProtoType *fnType) const {
// The following conventions are known to require this to be false:
// x86_stdcall
// MIPS
// For everything else, we just prefer false unless we opt out.
return false;
}
void
TargetCodeGenInfo::getDependentLibraryOption(llvm::StringRef Lib,
llvm::SmallString<24> &Opt) const {
// This assumes the user is passing a library name like "rt" instead of a
// filename like "librt.a/so", and that they don't care whether it's static or
// dynamic.
Opt = "-l";
Opt += Lib;
}
unsigned TargetCodeGenInfo::getOpenCLKernelCallingConv() const {
// OpenCL kernels are called via an explicit runtime API with arguments
// set with clSetKernelArg(), not as normal sub-functions.
// Return SPIR_KERNEL by default as the kernel calling convention to
// ensure the fingerprint is fixed such way that each OpenCL argument
// gets one matching argument in the produced kernel function argument
// list to enable feasible implementation of clSetKernelArg() with
// aggregates etc. In case we would use the default C calling conv here,
// clSetKernelArg() might break depending on the target-specific
// conventions; different targets might split structs passed as values
// to multiple function arguments etc.
return llvm::CallingConv::SPIR_KERNEL;
}
llvm::Constant *TargetCodeGenInfo::getNullPointer(const CodeGen::CodeGenModule &CGM,
llvm::PointerType *T, QualType QT) const {
return llvm::ConstantPointerNull::get(T);
}
LangAS TargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
const VarDecl *D) const {
assert(!CGM.getLangOpts().OpenCL &&
!(CGM.getLangOpts().CUDA && CGM.getLangOpts().CUDAIsDevice) &&
"Address space agnostic languages only");
return D ? D->getType().getAddressSpace() : LangAS::Default;
}
llvm::Value *TargetCodeGenInfo::performAddrSpaceCast(
CodeGen::CodeGenFunction &CGF, llvm::Value *Src, LangAS SrcAddr,
LangAS DestAddr, llvm::Type *DestTy, bool isNonNull) const {
// Since target may map different address spaces in AST to the same address
// space, an address space conversion may end up as a bitcast.
if (auto *C = dyn_cast<llvm::Constant>(Src))
return performAddrSpaceCast(CGF.CGM, C, SrcAddr, DestAddr, DestTy);
return CGF.Builder.CreatePointerBitCastOrAddrSpaceCast(Src, DestTy);
}
llvm::Constant *
TargetCodeGenInfo::performAddrSpaceCast(CodeGenModule &CGM, llvm::Constant *Src,
LangAS SrcAddr, LangAS DestAddr,
llvm::Type *DestTy) const {
// Since target may map different address spaces in AST to the same address
// space, an address space conversion may end up as a bitcast.
return llvm::ConstantExpr::getPointerCast(Src, DestTy);
}
llvm::SyncScope::ID
TargetCodeGenInfo::getLLVMSyncScopeID(SyncScope S, llvm::LLVMContext &C) const {
return C.getOrInsertSyncScopeID(""); /* default sync scope */
}
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.
// Constant arrays of zero length always count as empty.
if (AllowArrays)
while (const ConstantArrayType *AT = Context.getAsConstantArrayType(FT)) {
if (AT->getSize() == 0)
return true;
FT = AT->getElementType();
}
const RecordType *RT = FT->getAs<RecordType>();
if (!RT)
return false;
// C++ record fields are never empty, at least in the Itanium ABI.
//
// FIXME: We should use a predicate for whether this behavior is true in the
// current ABI.
if (isa<CXXRecordDecl>(RT->getDecl()))
return false;
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 false;
const RecordDecl *RD = RT->getDecl();
if (RD->hasFlexibleArrayMember())
return false;
// If this is a C++ record, check the bases first.
if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD))
for (const auto &I : CXXRD->bases())
if (!isEmptyRecord(Context, I.getType(), true))
return false;
for (const auto *I : RD->fields())
if (!isEmptyField(Context, I, AllowArrays))
return false;
return true;
}
/// 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->getAs<RecordType>();
if (!RT)
return nullptr;
const RecordDecl *RD = RT->getDecl();
if (RD->hasFlexibleArrayMember())
return nullptr;
const Type *Found = nullptr;
// If this is a C++ record, check the bases first.
if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD)) {
for (const auto &I : CXXRD->bases()) {
// Ignore empty records.
if (isEmptyRecord(Context, I.getType(), true))
continue;
// If we already found an element then this isn't a single-element struct.
if (Found)
return nullptr;
// If this is non-empty and not a single element struct, the composite
// cannot be a single element struct.
Found = isSingleElementStruct(I.getType(), Context);
if (!Found)
return nullptr;
}
}
// Check for single element.
for (const auto *FD : RD->fields()) {
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 nullptr;
// Treat single element arrays as the element.
while (const ConstantArrayType *AT = Context.getAsConstantArrayType(FT)) {
if (AT->getSize().getZExtValue() != 1)
break;
FT = AT->getElementType();
}
if (!isAggregateTypeForABI(FT)) {
Found = FT.getTypePtr();
} else {
Found = isSingleElementStruct(FT, Context);
if (!Found)
return nullptr;
}
}
// We don't consider a struct a single-element struct if it has
// padding beyond the element type.
if (Found && Context.getTypeSize(Found) != Context.getTypeSize(T))
return nullptr;
return Found;
}
namespace {
Address EmitVAArgInstr(CodeGenFunction &CGF, Address VAListAddr, QualType Ty,
const ABIArgInfo &AI) {
// This default implementation defers to the llvm backend's va_arg
// instruction. It can handle only passing arguments directly
// (typically only handled in the backend for primitive types), or
// aggregates passed indirectly by pointer (NOTE: if the "byval"
// flag has ABI impact in the callee, this implementation cannot
// work.)
// Only a few cases are covered here at the moment -- those needed
// by the default abi.
llvm::Value *Val;
if (AI.isIndirect()) {
assert(!AI.getPaddingType() &&
"Unexpected PaddingType seen in arginfo in generic VAArg emitter!");
assert(
!AI.getIndirectRealign() &&
"Unexpected IndirectRealign seen in arginfo in generic VAArg emitter!");
auto TyInfo = CGF.getContext().getTypeInfoInChars(Ty);
CharUnits TyAlignForABI = TyInfo.second;
llvm::Type *BaseTy =
llvm::PointerType::getUnqual(CGF.ConvertTypeForMem(Ty));
llvm::Value *Addr =
CGF.Builder.CreateVAArg(VAListAddr.getPointer(), BaseTy);
return Address(Addr, TyAlignForABI);
} else {
assert((AI.isDirect() || AI.isExtend()) &&
"Unexpected ArgInfo Kind in generic VAArg emitter!");
assert(!AI.getInReg() &&
"Unexpected InReg seen in arginfo in generic VAArg emitter!");
assert(!AI.getPaddingType() &&
"Unexpected PaddingType seen in arginfo in generic VAArg emitter!");
assert(!AI.getDirectOffset() &&
"Unexpected DirectOffset seen in arginfo in generic VAArg emitter!");
assert(!AI.getCoerceToType() &&
"Unexpected CoerceToType seen in arginfo in generic VAArg emitter!");
Address Temp = CGF.CreateMemTemp(Ty, "varet");
Val = CGF.Builder.CreateVAArg(VAListAddr.getPointer(), CGF.ConvertType(Ty));
CGF.Builder.CreateStore(Val, Temp);
return Temp;
}
}
/// 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 {
public:
DefaultABIInfo(CodeGen::CodeGenTypes &CGT) : ABIInfo(CGT) {}
ABIArgInfo classifyReturnType(QualType RetTy) const;
ABIArgInfo classifyArgumentType(QualType RetTy) const;
void computeInfo(CGFunctionInfo &FI) const override {
if (!getCXXABI().classifyReturnType(FI))
FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
for (auto &I : FI.arguments())
I.info = classifyArgumentType(I.type);
}
Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const override {
return EmitVAArgInstr(CGF, VAListAddr, Ty, classifyArgumentType(Ty));
}
};
class DefaultTargetCodeGenInfo : public TargetCodeGenInfo {
public:
DefaultTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
: TargetCodeGenInfo(new DefaultABIInfo(CGT)) {}
};
ABIArgInfo DefaultABIInfo::classifyArgumentType(QualType Ty) const {
Ty = useFirstFieldIfTransparentUnion(Ty);
if (isAggregateTypeForABI(Ty)) {
// Records with non-trivial destructors/copy-constructors should not be
// passed by value.
if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI()))
return getNaturalAlignIndirect(Ty, RAA == CGCXXABI::RAA_DirectInMemory);
return getNaturalAlignIndirect(Ty);
}
// Treat an enum type as its underlying type.
if (const EnumType *EnumTy = Ty->getAs<EnumType>())
Ty = EnumTy->getDecl()->getIntegerType();
return (Ty->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
ABIArgInfo DefaultABIInfo::classifyReturnType(QualType RetTy) const {
if (RetTy->isVoidType())
return ABIArgInfo::getIgnore();
if (isAggregateTypeForABI(RetTy))
return getNaturalAlignIndirect(RetTy);
// Treat an enum type as its underlying type.
if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
RetTy = EnumTy->getDecl()->getIntegerType();
return (RetTy->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
//===----------------------------------------------------------------------===//
// WebAssembly ABI Implementation
//
// This is a very simple ABI that relies a lot on DefaultABIInfo.
//===----------------------------------------------------------------------===//
class WebAssemblyABIInfo final : public DefaultABIInfo {
public:
explicit WebAssemblyABIInfo(CodeGen::CodeGenTypes &CGT)
: DefaultABIInfo(CGT) {}
private:
ABIArgInfo classifyReturnType(QualType RetTy) const;
ABIArgInfo classifyArgumentType(QualType Ty) const;
// DefaultABIInfo's classifyReturnType and classifyArgumentType are
// non-virtual, but computeInfo and EmitVAArg are virtual, so we
// overload them.
void computeInfo(CGFunctionInfo &FI) const override {
if (!getCXXABI().classifyReturnType(FI))
FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
for (auto &Arg : FI.arguments())
Arg.info = classifyArgumentType(Arg.type);
}
Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const override;
};
class WebAssemblyTargetCodeGenInfo final : public TargetCodeGenInfo {
public:
explicit WebAssemblyTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
: TargetCodeGenInfo(new WebAssemblyABIInfo(CGT)) {}
};
/// \brief Classify argument of given type \p Ty.
ABIArgInfo WebAssemblyABIInfo::classifyArgumentType(QualType Ty) const {
Ty = useFirstFieldIfTransparentUnion(Ty);
if (isAggregateTypeForABI(Ty)) {
// Records with non-trivial destructors/copy-constructors should not be
// passed by value.
if (auto RAA = getRecordArgABI(Ty, getCXXABI()))
return getNaturalAlignIndirect(Ty, RAA == CGCXXABI::RAA_DirectInMemory);
// Ignore empty structs/unions.
if (isEmptyRecord(getContext(), Ty, true))
return ABIArgInfo::getIgnore();
// Lower single-element structs to just pass a regular value. TODO: We
// could do reasonable-size multiple-element structs too, using getExpand(),
// though watch out for things like bitfields.
if (const Type *SeltTy = isSingleElementStruct(Ty, getContext()))
return ABIArgInfo::getDirect(CGT.ConvertType(QualType(SeltTy, 0)));
}
// Otherwise just do the default thing.
return DefaultABIInfo::classifyArgumentType(Ty);
}
ABIArgInfo WebAssemblyABIInfo::classifyReturnType(QualType RetTy) const {
if (isAggregateTypeForABI(RetTy)) {
// Records with non-trivial destructors/copy-constructors should not be
// returned by value.
if (!getRecordArgABI(RetTy, getCXXABI())) {
// Ignore empty structs/unions.
if (isEmptyRecord(getContext(), RetTy, true))
return ABIArgInfo::getIgnore();
// Lower single-element structs to just return a regular value. TODO: We
// could do reasonable-size multiple-element structs too, using
// ABIArgInfo::getDirect().
if (const Type *SeltTy = isSingleElementStruct(RetTy, getContext()))
return ABIArgInfo::getDirect(CGT.ConvertType(QualType(SeltTy, 0)));
}
}
// Otherwise just do the default thing.
return DefaultABIInfo::classifyReturnType(RetTy);
}
Address WebAssemblyABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const {
return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*Indirect=*/ false,
getContext().getTypeInfoInChars(Ty),
CharUnits::fromQuantity(4),
/*AllowHigherAlign=*/ true);
}
//===----------------------------------------------------------------------===//
// le32/PNaCl bitcode ABI Implementation
//
// This is a simplified version of the x86_32 ABI. Arguments and return values
// are always passed on the stack.
//===----------------------------------------------------------------------===//
class PNaClABIInfo : public ABIInfo {
public:
PNaClABIInfo(CodeGen::CodeGenTypes &CGT) : ABIInfo(CGT) {}
ABIArgInfo classifyReturnType(QualType RetTy) const;
ABIArgInfo classifyArgumentType(QualType RetTy) const;
void computeInfo(CGFunctionInfo &FI) const override;
Address EmitVAArg(CodeGenFunction &CGF,
Address VAListAddr, QualType Ty) const override;
};
class PNaClTargetCodeGenInfo : public TargetCodeGenInfo {
public:
PNaClTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
: TargetCodeGenInfo(new PNaClABIInfo(CGT)) {}
};
void PNaClABIInfo::computeInfo(CGFunctionInfo &FI) const {
if (!getCXXABI().classifyReturnType(FI))
FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
for (auto &I : FI.arguments())
I.info = classifyArgumentType(I.type);
}
Address PNaClABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
QualType Ty) const {
// The PNaCL ABI is a bit odd, in that varargs don't use normal
// function classification. Structs get passed directly for varargs
// functions, through a rewriting transform in
// pnacl-llvm/lib/Transforms/NaCl/ExpandVarArgs.cpp, which allows
// this target to actually support a va_arg instructions with an
// aggregate type, unlike other targets.
return EmitVAArgInstr(CGF, VAListAddr, Ty, ABIArgInfo::getDirect());
}
/// \brief Classify argument of given type \p Ty.
ABIArgInfo PNaClABIInfo::classifyArgumentType(QualType Ty) const {
if (isAggregateTypeForABI(Ty)) {
if (CGCXXABI::RecordArgABI RAA = getRecordArgABI(Ty, getCXXABI()))
return getNaturalAlignIndirect(Ty, RAA == CGCXXABI::RAA_DirectInMemory);
return getNaturalAlignIndirect(Ty);
} else if (const EnumType *EnumTy = Ty->getAs<EnumType>()) {
// Treat an enum type as its underlying type.
Ty = EnumTy->getDecl()->getIntegerType();
} else if (Ty->isFloatingType()) {
// Floating-point types don't go inreg.
return ABIArgInfo::getDirect();
}
return (Ty->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
ABIArgInfo PNaClABIInfo::classifyReturnType(QualType RetTy) const {
if (RetTy->isVoidType())
return ABIArgInfo::getIgnore();
// In the PNaCl ABI we always return records/structures on the stack.
if (isAggregateTypeForABI(RetTy))
return getNaturalAlignIndirect(RetTy);
// Treat an enum type as its underlying type.
if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
RetTy = EnumTy->getDecl()->getIntegerType();
return (RetTy->isPromotableIntegerType() ?
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
/// IsX86_MMXType - Return true if this is an MMX type.
bool IsX86_MMXType(llvm::Type *IRType) {
// Return true if the type is an MMX type <2 x i32>, <4 x i16>, or <8 x i8>.
return IRType->isVectorTy() && IRType->getPrimitiveSizeInBits() == 64 &&
cast<llvm::VectorType>(IRType)->getElementType()->isIntegerTy() &&
IRType->getScalarSizeInBits() != 64;
}
static llvm::Type* X86AdjustInlineAsmType(CodeGen::CodeGenFunction &CGF,
StringRef Constraint,
llvm::Type* Ty) {
bool IsMMXCons = llvm::StringSwitch<bool>(Constraint)
.Cases("y", "&y", "^Ym", true)
.Default(false);
if (IsMMXCons && Ty->isVectorTy()) {
if (cast<llvm::VectorType>(Ty)->getBitWidth() != 64) {
// Invalid MMX constraint
return nullptr;
}
return llvm::Type::getX86_MMXTy(CGF.getLLVMContext());
}
// No operation needed
return Ty;
}
/// Returns true if this type can be passed in SSE registers with the
/// X86_VectorCall calling convention. Shared between x86_32 and x86_64.
static bool isX86VectorTypeForVectorCall(ASTContext &Context, QualType Ty) {
if (const BuiltinType *BT = Ty->getAs<BuiltinType>()) {
if (BT->isFloatingPoint() && BT->getKind() != BuiltinType::Half) {
if (BT->getKind() == BuiltinType::LongDouble) {
if (&Context.getTargetInfo().getLongDoubleFormat() ==
&llvm::APFloat::x87DoubleExtended())
return false;
}
return true;
}
} else if (const VectorType *VT = Ty->getAs<VectorType>()) {
// vectorcall can pass XMM, YMM, and ZMM vectors. We don't pass SSE1 MMX
// registers specially.
unsigned VecSize = Context.getTypeSize(VT);
if (VecSize == 128 || VecSize == 256 || VecSize == 512)
return true;
}
return false;
}
/// Returns true if this aggregate is small enough to be passed in SSE registers
/// in the X86_VectorCall calling convention. Shared between x86_32 and x86_64.
static bool isX86VectorCallAggregateSmallEnough(uint64_t NumMembers) {
return NumMembers <= 4;
}
/// Returns a Homogeneous Vector Aggregate ABIArgInfo, used in X86.
static ABIArgInfo getDirectX86Hva(llvm::Type* T = nullptr) {
auto AI = ABIArgInfo::getDirect(T);
AI.setInReg(true);
AI.setCanBeFlattened(false);
return AI;
}
//===----------------------------------------------------------------------===//
// X86-32 ABI Implementation
//===----------------------------------------------------------------------===//
/// \brief Similar to llvm::CCState, but for Clang.
struct CCState {
CCState(unsigned CC) : CC(CC), FreeRegs(0), FreeSSERegs(0) {}
unsigned CC;
unsigned FreeRegs;
unsigned FreeSSERegs;
};
enum {
// Vectorcall only allows the first 6 parameters to be passed in registers.
VectorcallMaxParamNumAsReg = 6
};
/// X86_32ABIInfo - The X86-32 ABI information.
class X86_32ABIInfo : public SwiftABIInfo {
enum Class {
Integer,
Float
};
static const unsigned MinABIStackAlignInBytes = 4;
bool IsDarwinVectorABI;
bool IsRetSmallStructInRegABI;
bool IsWin32StructABI;
bool IsSoftFloatABI;
bool IsMCUABI;
unsigned DefaultNumRegisterParameters;
static bool isRegisterSize(unsigned Size) {
return (Size == 8 || Size == 16 || Size == 32 || Size == 64);
}
bool isHomogeneousAggregateBaseType(QualType Ty) const override {
// FIXME: Assumes vectorcall is in use.
return isX86VectorTypeForVectorCall(getContext(), Ty);
}
bool isHomogeneousAggregateSmallEnough(const Type *Ty,
uint64_t NumMembers) const override {
// FIXME: Assumes vectorcall is in use.
return isX86VectorCallAggregateSmallEnough(NumMembers);
}
bool shouldReturnTypeInRegister(QualType Ty, 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, bool ByVal, CCState &State) const;
ABIArgInfo getIndirectReturnResult(QualType Ty, CCState &State) const;
/// \brief Return the alignment to use for the given type on the stack.
unsigned getTypeStackAlignInBytes(QualType Ty, unsigned Align) const;
Class classify(QualType Ty) const;
ABIArgInfo classifyReturnType(QualType RetTy, CCState &State) const;
ABIArgInfo classifyArgumentType(QualType RetTy, CCState &State) const;
/// \brief Updates the number of available free registers, returns
/// true if any registers were allocated.
bool updateFreeRegs(QualType Ty, CCState &State) const;
bool shouldAggregateUseDirect(QualType Ty, CCState &State, bool &InReg,
bool &NeedsPadding) const;