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

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//===----- CGCall.h - Encapsulate calling convention 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 "CGCall.h"
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/RecordLayout.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Attributes.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetData.h"
#include "ABIInfo.h"
using namespace clang;
using namespace CodeGen;
/***/
// FIXME: Use iterator and sidestep silly type array creation.
const
CGFunctionInfo &CodeGenTypes::getFunctionInfo(const FunctionNoProtoType *FTNP) {
return getFunctionInfo(FTNP->getResultType(),
llvm::SmallVector<QualType, 16>());
}
const
CGFunctionInfo &CodeGenTypes::getFunctionInfo(const FunctionProtoType *FTP) {
llvm::SmallVector<QualType, 16> ArgTys;
// FIXME: Kill copy.
for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
ArgTys.push_back(FTP->getArgType(i));
return getFunctionInfo(FTP->getResultType(), ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const FunctionDecl *FD) {
const FunctionType *FTy = FD->getType()->getAsFunctionType();
if (const FunctionProtoType *FTP = dyn_cast<FunctionProtoType>(FTy))
return getFunctionInfo(FTP);
return getFunctionInfo(cast<FunctionNoProtoType>(FTy));
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(const ObjCMethodDecl *MD) {
llvm::SmallVector<QualType, 16> ArgTys;
ArgTys.push_back(MD->getSelfDecl()->getType());
ArgTys.push_back(Context.getObjCSelType());
// FIXME: Kill copy?
for (ObjCMethodDecl::param_iterator i = MD->param_begin(),
e = MD->param_end(); i != e; ++i)
ArgTys.push_back((*i)->getType());
return getFunctionInfo(MD->getResultType(), ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy,
const CallArgList &Args) {
// FIXME: Kill copy.
llvm::SmallVector<QualType, 16> ArgTys;
for (CallArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i)
ArgTys.push_back(i->second);
return getFunctionInfo(ResTy, ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy,
const FunctionArgList &Args) {
// FIXME: Kill copy.
llvm::SmallVector<QualType, 16> ArgTys;
for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i)
ArgTys.push_back(i->second);
return getFunctionInfo(ResTy, ArgTys);
}
const CGFunctionInfo &CodeGenTypes::getFunctionInfo(QualType ResTy,
const llvm::SmallVector<QualType, 16> &ArgTys) {
// Lookup or create unique function info.
llvm::FoldingSetNodeID ID;
CGFunctionInfo::Profile(ID, ResTy, ArgTys.begin(), ArgTys.end());
void *InsertPos = 0;
CGFunctionInfo *FI = FunctionInfos.FindNodeOrInsertPos(ID, InsertPos);
if (FI)
return *FI;
// Construct the function info.
FI = new CGFunctionInfo(ResTy, ArgTys);
FunctionInfos.InsertNode(FI, InsertPos);
// Compute ABI information.
getABIInfo().computeInfo(*FI, getContext());
return *FI;
}
/***/
ABIInfo::~ABIInfo() {}
void ABIArgInfo::dump() const {
fprintf(stderr, "(ABIArgInfo Kind=");
switch (TheKind) {
case Direct:
fprintf(stderr, "Direct");
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");
}
/***/
/// isEmptyStruct - Return true iff a structure has no non-empty
/// members. Note that a structure with a flexible array member is not
/// considered empty.
static bool isEmptyStruct(QualType T) {
const RecordType *RT = T->getAsStructureType();
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) {
const FieldDecl *FD = *i;
if (!isEmptyStruct(FD->getType()))
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 FieldDecl *isSingleElementStruct(QualType T) {
const RecordType *RT = T->getAsStructureType();
if (!RT)
return 0;
const RecordDecl *RD = RT->getDecl();
if (RD->hasFlexibleArrayMember())
return 0;
const FieldDecl *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();
if (isEmptyStruct(FT)) {
// Ignore
} else if (Found) {
return 0;
} else if (!CodeGenFunction::hasAggregateLLVMType(FT)) {
Found = FD;
} else {
Found = isSingleElementStruct(FT);
if (!Found)
return 0;
}
}
return Found;
}
static bool is32Or64BitBasicType(QualType Ty, ASTContext &Context) {
if (!Ty->getAsBuiltinType() && !Ty->isPointerType())
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 bitfields 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;
}
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) const;
ABIArgInfo classifyArgumentType(QualType RetTy,
ASTContext &Context) const;
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), Context);
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it)
it->info = classifyArgumentType(it->type, Context);
}
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
};
/// X86_32ABIInfo - The X86-32 ABI information.
class X86_32ABIInfo : public ABIInfo {
bool IsDarwin;
public:
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context) const;
ABIArgInfo classifyArgumentType(QualType RetTy,
ASTContext &Context) const;
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), Context);
for (CGFunctionInfo::arg_iterator it = FI.arg_begin(), ie = FI.arg_end();
it != ie; ++it)
it->info = classifyArgumentType(it->type, Context);
}
virtual llvm::Value *EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const;
X86_32ABIInfo(bool d) : ABIInfo(), IsDarwin(d) {}
};
}
ABIArgInfo X86_32ABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context) const {
if (RetTy->isVoidType()) {
return ABIArgInfo::getIgnore();
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
// Outside of Darwin, structs and unions are always indirect.
if (!IsDarwin && !RetTy->isAnyComplexType())
return ABIArgInfo::getIndirect(0);
// Classify "single element" structs as their element type.
const FieldDecl *SeltFD = isSingleElementStruct(RetTy);
if (SeltFD) {
QualType SeltTy = SeltFD->getType()->getDesugaredType();
if (const BuiltinType *BT = SeltTy->getAsBuiltinType()) {
// FIXME: This is gross, it would be nice if we could just
// pass back SeltTy and have clients deal with it. Is it worth
// supporting coerce to both LLVM and clang Types?
if (BT->isIntegerType()) {
uint64_t Size = Context.getTypeSize(SeltTy);
return ABIArgInfo::getCoerce(llvm::IntegerType::get((unsigned) Size));
} else if (BT->getKind() == BuiltinType::Float) {
return ABIArgInfo::getCoerce(llvm::Type::FloatTy);
} else if (BT->getKind() == BuiltinType::Double) {
return ABIArgInfo::getCoerce(llvm::Type::DoubleTy);
}
} 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::Int8Ty);
return ABIArgInfo::getCoerce(PtrTy);
}
}
uint64_t Size = Context.getTypeSize(RetTy);
if (Size == 8) {
return ABIArgInfo::getCoerce(llvm::Type::Int8Ty);
} else if (Size == 16) {
return ABIArgInfo::getCoerce(llvm::Type::Int16Ty);
} else if (Size == 32) {
return ABIArgInfo::getCoerce(llvm::Type::Int32Ty);
} else if (Size == 64) {
return ABIArgInfo::getCoerce(llvm::Type::Int64Ty);
} else {
return ABIArgInfo::getIndirect(0);
}
} else {
return ABIArgInfo::getDirect();
}
}
ABIArgInfo X86_32ABIInfo::classifyArgumentType(QualType Ty,
ASTContext &Context) 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(0);
// Ignore empty structs.
uint64_t Size = Context.getTypeSize(Ty);
if (Ty->isStructureType() && Size == 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(0);
} else {
return ABIArgInfo::getDirect();
}
}
llvm::Value *X86_32ABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
CodeGenFunction &CGF) const {
const llvm::Type *BP = llvm::PointerType::getUnqual(llvm::Type::Int8Ty);
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::Int32Ty, 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;
ABIArgInfo classifyReturnType(QualType RetTy,
ASTContext &Context) const;
ABIArgInfo classifyArgumentType(QualType Ty,
ASTContext &Context,
unsigned &neededInt,
unsigned &neededSSE) const;
public:
virtual void computeInfo(CGFunctionInfo &FI, ASTContext &Context) 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)
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->getAsBuiltinType()) {
BuiltinType::Kind k = BT->getKind();
if (k == BuiltinType::Void) {
Current = NoClass;
} 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).
// FIXME: __int128 is (Integer, Integer).
} else if (const EnumType *ET = Ty->getAsEnumType()) {
// 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->getAsVectorType()) {
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->getAsComplexType()) {
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->getAsRecordType()) {
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;
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 bitfields, 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;
// Bitfields 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) {
uint64_t Offset = OffsetBase + Layout.getFieldOffset(idx);
uint64_t Size =
i->getBitWidth()->getIntegerConstantExprValue(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::Int64Ty) {
// Integer and pointer types will end up in a general purpose
// register.
if (Ty->isIntegralType() || Ty->isPointerType())
return ABIArgInfo::getDirect();
} else if (CoerceTo == llvm::Type::DoubleTy) {
// 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::classifyReturnType(QualType RetTy,
ASTContext &Context) 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 ABIArgInfo::getIndirect(0);
// 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::Int64Ty; 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::DoubleTy; 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::X86_FP80Ty; 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(llvm::Type::X86_FP80Ty,
llvm::Type::X86_FP80Ty,
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(ResType, llvm::Type::Int64Ty, NULL);
break;
case SSE:
ResType = llvm::StructType::get(ResType, llvm::Type::DoubleTy, 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::DoubleTy, 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(ResType, llvm::Type::DoubleTy, NULL);
break;
}
return getCoerceResult(RetTy, ResType, Context);
}
ABIArgInfo X86_64ABIInfo::classifyArgumentType(QualType Ty, ASTContext &Context,
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 ABIArgInfo::getIndirect(0);
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::Int64Ty;
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::DoubleTy;
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(ResType, llvm::Type::Int64Ty, 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(ResType, llvm::Type::DoubleTy, 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::DoubleTy, 2);
break;
}
return getCoerceResult(Ty, ResType, Context);
}
void X86_64ABIInfo::computeInfo(CGFunctionInfo &FI, ASTContext &Context) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType(), Context);
// Keep track of the number of assigned registers.
unsigned freeIntRegs = 6, freeSSERegs = 8;
// 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, 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 = ABIArgInfo::getIndirect(0);
}
}
}
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::Int32Ty, 15);
overflow_arg_area = CGF.Builder.CreateGEP(overflow_arg_area, Offset);
llvm::Value *AsInt = CGF.Builder.CreatePtrToInt(overflow_arg_area,
llvm::Type::Int64Ty);
llvm::Value *Mask = llvm::ConstantInt::get(llvm::Type::Int64Ty, ~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::Int32Ty,
(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 {
// 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(),
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(llvm::Type::Int32Ty,
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(llvm::Type::Int32Ty,
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(llvm::Type::Int32Ty, 16));
const llvm::Type *DblPtrTy =
llvm::PointerType::getUnqual(llvm::Type::DoubleTy);
const llvm::StructType *ST = llvm::StructType::get(llvm::Type::DoubleTy,
llvm::Type::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(llvm::Type::Int32Ty,
neededInt * 8);
CGF.Builder.CreateStore(CGF.Builder.CreateAdd(gp_offset, Offset),
gp_offset_p);
}
if (neededSSE) {
llvm::Value *Offset = llvm::ConstantInt::get(llvm::Type::Int32Ty,
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;
}
ABIArgInfo DefaultABIInfo::classifyReturnType(QualType RetTy,
ASTContext &Context) const {
if (RetTy->isVoidType()) {
return ABIArgInfo::getIgnore();
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
return ABIArgInfo::getIndirect(0);
} else {
return ABIArgInfo::getDirect();
}
}
ABIArgInfo DefaultABIInfo::classifyArgumentType(QualType Ty,
ASTContext &Context) const {
if (CodeGenFunction::hasAggregateLLVMType(Ty)) {
return ABIArgInfo::getIndirect(0);
} else {
return 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 this in the CodeGenTypes and don't bother
// to free it.
const char *TargetPrefix = getContext().Target.getTargetPrefix();
if (strcmp(TargetPrefix, "x86") == 0) {
bool IsDarwin = strstr(getContext().Target.getTargetTriple(), "darwin");
switch (getContext().Target.getPointerWidth(0)) {
case 32:
return *(TheABIInfo = new X86_32ABIInfo(IsDarwin));
case 64:
return *(TheABIInfo = new X86_64ABIInfo());
}
}
return *(TheABIInfo = new DefaultABIInfo);
}
/***/
CGFunctionInfo::CGFunctionInfo(QualType ResTy,
const llvm::SmallVector<QualType, 16> &ArgTys) {
NumArgs = ArgTys.size();
Args = new ArgInfo[1 + NumArgs];
Args[0].type = ResTy;
for (unsigned i = 0; i < NumArgs; ++i)
Args[1 + i].type = ArgTys[i];
}
/***/
void CodeGenTypes::GetExpandedTypes(QualType Ty,
std::vector<const llvm::Type*> &ArgTys) {
const RecordType *RT = Ty->getAsStructureType();
assert(RT && "Can only expand structure types.");
const RecordDecl *RD = RT->getDecl();
assert(!RD->hasFlexibleArrayMember() &&
"Cannot expand structure with flexible array.");
for (RecordDecl::field_iterator i = RD->field_begin(),
e = RD->field_end(); i != e; ++i) {
const FieldDecl *FD = *i;
assert(!FD->isBitField() &&
"Cannot expand structure with bit-field members.");
QualType FT = FD->getType();
if (CodeGenFunction::hasAggregateLLVMType(FT)) {
GetExpandedTypes(FT, ArgTys);
} else {
ArgTys.push_back(ConvertType(FT));
}
}
}
llvm::Function::arg_iterator
CodeGenFunction::ExpandTypeFromArgs(QualType Ty, LValue LV,
llvm::Function::arg_iterator AI) {
const RecordType *RT = Ty->getAsStructureType();
assert(RT && "Can only expand structure types.");
RecordDecl *RD = RT->getDecl();
assert(LV.isSimple() &&
"Unexpected non-simple lvalue during struct expansion.");
llvm::Value *Addr = LV.getAddress();
for (RecordDecl::field_iterator i = RD->field_begin(),
e = RD->field_end(); i != e; ++i) {
FieldDecl *FD = *i;
QualType FT = FD->getType();
// FIXME: What are the right qualifiers here?
LValue LV = EmitLValueForField(Addr, FD, false, 0);
if (CodeGenFunction::hasAggregateLLVMType(FT)) {
AI = ExpandTypeFromArgs(FT, LV, AI);
} else {
EmitStoreThroughLValue(RValue::get(AI), LV, FT);
++AI;
}
}
return AI;
}
void
CodeGenFunction::ExpandTypeToArgs(QualType Ty, RValue RV,
llvm::SmallVector<llvm::Value*, 16> &Args) {
const RecordType *RT = Ty->getAsStructureType();
assert(RT && "Can only expand structure types.");
RecordDecl *RD = RT->getDecl();
assert(RV.isAggregate() && "Unexpected rvalue during struct expansion");
llvm::Value *Addr = RV.getAggregateAddr();
for (RecordDecl::field_iterator i = RD->field_begin(),
e = RD->field_end(); i != e; ++i) {
FieldDecl *FD = *i;
QualType FT = FD->getType();
// FIXME: What are the right qualifiers here?
LValue LV = EmitLValueForField(Addr, FD, false, 0);
if (CodeGenFunction::hasAggregateLLVMType(FT)) {
ExpandTypeToArgs(FT, RValue::getAggregate(LV.getAddress()), Args);
} else {
RValue RV = EmitLoadOfLValue(LV, FT);
assert(RV.isScalar() &&
"Unexpected non-scalar rvalue during struct expansion.");
Args.push_back(RV.getScalarVal());
}
}
}
/// CreateCoercedLoad - Create a load from \arg SrcPtr interpreted as
/// a pointer to an object of type \arg Ty.
///
/// This safely handles the case when the src type is smaller than the
/// destination type; in this situation the values of bits which not
/// present in the src are undefined.
static llvm::Value *CreateCoercedLoad(llvm::Value *SrcPtr,
const llvm::Type *Ty,
CodeGenFunction &CGF) {
const llvm::Type *SrcTy =
cast<llvm::PointerType>(SrcPtr->getType())->getElementType();
uint64_t SrcSize = CGF.CGM.getTargetData().getTypePaddedSize(SrcTy);
uint64_t DstSize = CGF.CGM.getTargetData().getTypePaddedSize(Ty);
// If load is legal, just bitcast the src pointer.
if (SrcSize == DstSize) {
llvm::Value *Casted =
CGF.Builder.CreateBitCast(SrcPtr, llvm::PointerType::getUnqual(Ty));
llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted);
// FIXME: Use better alignment / avoid requiring aligned load.
Load->setAlignment(1);
return Load;
} else {
assert(SrcSize < DstSize && "Coercion is losing source bits!");
// Otherwise do coercion through memory. This is stupid, but
// simple.
llvm::Value *Tmp = CGF.CreateTempAlloca(Ty);
llvm::Value *Casted =
CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(SrcTy));
llvm::StoreInst *Store =
CGF.Builder.CreateStore(CGF.Builder.CreateLoad(SrcPtr), Casted);
// FIXME: Use better alignment / avoid requiring aligned store.
Store->setAlignment(1);
return CGF.Builder.CreateLoad(Tmp);
}
}
/// CreateCoercedStore - Create a store to \arg DstPtr from \arg Src,
/// where the source and destination may have different types.
///
/// This safely handles the case when the src type is larger than the
/// destination type; the upper bits of the src will be lost.
static void CreateCoercedStore(llvm::Value *Src,
llvm::Value *DstPtr,
CodeGenFunction &CGF) {
const llvm::Type *SrcTy = Src->getType();
const llvm::Type *DstTy =
cast<llvm::PointerType>(DstPtr->getType())->getElementType();
uint64_t SrcSize = CGF.CGM.getTargetData().getTypePaddedSize(SrcTy);
uint64_t DstSize = CGF.CGM.getTargetData().getTypePaddedSize(DstTy);
// If store is legal, just bitcast the src pointer.
if (SrcSize == DstSize) {
llvm::Value *Casted =
CGF.Builder.CreateBitCast(DstPtr, llvm::PointerType::getUnqual(SrcTy));
// FIXME: Use better alignment / avoid requiring aligned store.
CGF.Builder.CreateStore(Src, Casted)->setAlignment(1);
} else {
assert(SrcSize > DstSize && "Coercion is missing bits!");
// Otherwise do coercion through memory. This is stupid, but
// simple.
llvm::Value *Tmp = CGF.CreateTempAlloca(SrcTy);
CGF.Builder.CreateStore(Src, Tmp);
llvm::Value *Casted =
CGF.Builder.CreateBitCast(Tmp, llvm::PointerType::getUnqual(DstTy));
llvm::LoadInst *Load = CGF.Builder.CreateLoad(Casted);
// FIXME: Use better alignment / avoid requiring aligned load.
Load->setAlignment(1);
CGF.Builder.CreateStore(Load, DstPtr);
}
}
/***/
bool CodeGenModule::ReturnTypeUsesSret(const CGFunctionInfo &FI) {
return FI.getReturnInfo().isIndirect();
}
const llvm::FunctionType *
CodeGenTypes::GetFunctionType(const CGFunctionInfo &FI, bool IsVariadic) {
std::vector<const llvm::Type*> ArgTys;
const llvm::Type *ResultType = 0;
QualType RetTy = FI.getReturnType();
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
case ABIArgInfo::Direct:
ResultType = ConvertType(RetTy);
break;
case ABIArgInfo::Indirect: {
assert(!RetAI.getIndirectAlign() && "Align unused on indirect return.");
ResultType = llvm::Type::VoidTy;
const llvm::Type *STy = ConvertType(RetTy);
ArgTys.push_back(llvm::PointerType::get(STy, RetTy.getAddressSpace()));
break;
}
case ABIArgInfo::Ignore:
ResultType = llvm::Type::VoidTy;
break;
case ABIArgInfo::Coerce:
ResultType = RetAI.getCoerceToType();
break;
}
for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
ie = FI.arg_end(); it != ie; ++it) {
const ABIArgInfo &AI = it->info;
switch (AI.getKind()) {
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Coerce:
ArgTys.push_back(AI.getCoerceToType());
break;
case ABIArgInfo::Indirect: {
// indirect arguments are always on the stack, which is addr space #0.
const llvm::Type *LTy = ConvertTypeForMem(it->type);
ArgTys.push_back(llvm::PointerType::getUnqual(LTy));
break;
}
case ABIArgInfo::Direct:
ArgTys.push_back(ConvertType(it->type));
break;
case ABIArgInfo::Expand:
GetExpandedTypes(it->type, ArgTys);
break;
}
}
return llvm::FunctionType::get(ResultType, ArgTys, IsVariadic);
}
void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
const Decl *TargetDecl,
AttributeListType &PAL) {
unsigned FuncAttrs = 0;
unsigned RetAttrs = 0;
if (TargetDecl) {
if (TargetDecl->getAttr<NoThrowAttr>())
FuncAttrs |= llvm::Attribute::NoUnwind;
if (TargetDecl->getAttr<NoReturnAttr>())
FuncAttrs |= llvm::Attribute::NoReturn;
if (TargetDecl->getAttr<PureAttr>())
FuncAttrs |= llvm::Attribute::ReadOnly;
if (TargetDecl->getAttr<ConstAttr>())
FuncAttrs |= llvm::Attribute::ReadNone;
}
QualType RetTy = FI.getReturnType();
unsigned Index = 1;
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Direct:
if (RetTy->isPromotableIntegerType()) {
if (RetTy->isSignedIntegerType()) {
RetAttrs |= llvm::Attribute::SExt;
} else if (RetTy->isUnsignedIntegerType()) {
RetAttrs |= llvm::Attribute::ZExt;
}
}
break;
case ABIArgInfo::Indirect:
PAL.push_back(llvm::AttributeWithIndex::get(Index,
llvm::Attribute::StructRet |
llvm::Attribute::NoAlias));
++Index;
// sret disables readnone and readonly
FuncAttrs &= ~(llvm::Attribute::ReadOnly |
llvm::Attribute::ReadNone);
break;
case ABIArgInfo::Ignore:
case ABIArgInfo::Coerce:
break;
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
}
if (RetAttrs)
PAL.push_back(llvm::AttributeWithIndex::get(0, RetAttrs));
for (CGFunctionInfo::const_arg_iterator it = FI.arg_begin(),
ie = FI.arg_end(); it != ie; ++it) {
QualType ParamType = it->type;
const ABIArgInfo &AI = it->info;
unsigned Attributes = 0;
switch (AI.getKind()) {
case ABIArgInfo::Coerce:
break;
case ABIArgInfo::Indirect:
Attributes |= llvm::Attribute::ByVal;
Attributes |=
llvm::Attribute::constructAlignmentFromInt(AI.getIndirectAlign());
// byval disables readnone and readonly.
FuncAttrs &= ~(llvm::Attribute::ReadOnly |
llvm::Attribute::ReadNone);
break;
case ABIArgInfo::Direct:
if (ParamType->isPromotableIntegerType()) {
if (ParamType->isSignedIntegerType()) {
Attributes |= llvm::Attribute::SExt;
} else if (ParamType->isUnsignedIntegerType()) {
Attributes |= llvm::Attribute::ZExt;
}
}
break;
case ABIArgInfo::Ignore:
// Skip increment, no matching LLVM parameter.
continue;
case ABIArgInfo::Expand: {
std::vector<const llvm::Type*> Tys;
// FIXME: This is rather inefficient. Do we ever actually need
// to do anything here? The result should be just reconstructed
// on the other side, so extension should be a non-issue.
getTypes().GetExpandedTypes(ParamType, Tys);
Index += Tys.size();
continue;
}
}
if (Attributes)
PAL.push_back(llvm::AttributeWithIndex::get(Index, Attributes));
++Index;
}
if (FuncAttrs)
PAL.push_back(llvm::AttributeWithIndex::get(~0, FuncAttrs));
}
void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
llvm::Function *Fn,
const FunctionArgList &Args) {
// FIXME: We no longer need the types from FunctionArgList; lift up
// and simplify.
// Emit allocs for param decls. Give the LLVM Argument nodes names.
llvm::Function::arg_iterator AI = Fn->arg_begin();
// Name the struct return argument.
if (CGM.ReturnTypeUsesSret(FI)) {
AI->setName("agg.result");
++AI;
}
assert(FI.arg_size() == Args.size() &&
"Mismatch between function signature & arguments.");
CGFunctionInfo::const_arg_iterator info_it = FI.arg_begin();
for (FunctionArgList::const_iterator i = Args.begin(), e = Args.end();
i != e; ++i, ++info_it) {
const VarDecl *Arg = i->first;
QualType Ty = info_it->type;
const ABIArgInfo &ArgI = info_it->info;
switch (ArgI.getKind()) {
case ABIArgInfo::Indirect: {
llvm::Value* V = AI;
if (hasAggregateLLVMType(Ty)) {
// Do nothing, aggregates and complex variables are accessed by
// reference.
} else {
// Load scalar value from indirect argument.
V = EmitLoadOfScalar(V, false, Ty);
if (!getContext().typesAreCompatible(Ty, Arg->getType())) {
// This must be a promotion, for something like
// "void a(x) short x; {..."
V = EmitScalarConversion(V, Ty, Arg->getType());
}
}
EmitParmDecl(*Arg, V);
break;
}
case ABIArgInfo::Direct: {
assert(AI != Fn->arg_end() && "Argument mismatch!");
llvm::Value* V = AI;
if (hasAggregateLLVMType(Ty)) {
// Create a temporary alloca to hold the argument; the rest of
// codegen expects to access aggregates & complex values by
// reference.
V = CreateTempAlloca(ConvertTypeForMem(Ty));
Builder.CreateStore(AI, V);
} else {
if (!getContext().typesAreCompatible(Ty, Arg->getType())) {
// This must be a promotion, for something like
// "void a(x) short x; {..."
V = EmitScalarConversion(V, Ty, Arg->getType());
}
}
EmitParmDecl(*Arg, V);
break;
}
case ABIArgInfo::Expand: {
// If this structure was expanded into multiple arguments then
// we need to create a temporary and reconstruct it from the
// arguments.
std::string Name = Arg->getNameAsString();
llvm::Value *Temp = CreateTempAlloca(ConvertTypeForMem(Ty),
(Name + ".addr").c_str());
// FIXME: What are the right qualifiers here?
llvm::Function::arg_iterator End =
ExpandTypeFromArgs(Ty, LValue::MakeAddr(Temp,0), AI);
EmitParmDecl(*Arg, Temp);
// Name the arguments used in expansion and increment AI.
unsigned Index = 0;
for (; AI != End; ++AI, ++Index)
AI->setName(Name + "." + llvm::utostr(Index));
continue;
}
case ABIArgInfo::Ignore:
// Initialize the local variable appropriately.
if (hasAggregateLLVMType(Ty)) {
EmitParmDecl(*Arg, CreateTempAlloca(ConvertTypeForMem(Ty)));
} else {
EmitParmDecl(*Arg, llvm::UndefValue::get(ConvertType(Arg->getType())));
}
// Skip increment, no matching LLVM parameter.
continue;
case ABIArgInfo::Coerce: {
assert(AI != Fn->arg_end() && "Argument mismatch!");
// FIXME: This is very wasteful; EmitParmDecl is just going to
// drop the result in a new alloca anyway, so we could just
// store into that directly if we broke the abstraction down
// more.
llvm::Value *V = CreateTempAlloca(ConvertTypeForMem(Ty), "coerce");
CreateCoercedStore(AI, V, *this);
// Match to what EmitParmDecl is expecting for this type.
if (!CodeGenFunction::hasAggregateLLVMType(Ty)) {
V = EmitLoadOfScalar(V, false, Ty);
if (!getContext().typesAreCompatible(Ty, Arg->getType())) {
// This must be a promotion, for something like
// "void a(x) short x; {..."
V = EmitScalarConversion(V, Ty, Arg->getType());
}
}
EmitParmDecl(*Arg, V);
break;
}
}
++AI;
}
assert(AI == Fn->arg_end() && "Argument mismatch!");
}
void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI,
llvm::Value *ReturnValue) {
llvm::Value *RV = 0;
// Functions with no result always return void.
if (ReturnValue) {
QualType RetTy = FI.getReturnType();
const ABIArgInfo &RetAI = FI.getReturnInfo();
switch (RetAI.getKind()) {
case ABIArgInfo::Indirect:
if (RetTy->isAnyComplexType()) {
ComplexPairTy RT = LoadComplexFromAddr(ReturnValue, false);
StoreComplexToAddr(RT, CurFn->arg_begin(), false);
} else if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
EmitAggregateCopy(CurFn->arg_begin(), ReturnValue, RetTy);
} else {
EmitStoreOfScalar(Builder.CreateLoad(ReturnValue), CurFn->arg_begin(),
false);
}
break;
case ABIArgInfo::Direct:
// The internal return value temp always will have
// pointer-to-return-type type.
RV = Builder.CreateLoad(ReturnValue);
break;
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Coerce:
RV = CreateCoercedLoad(ReturnValue, RetAI.getCoerceToType(), *this);
break;
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
}
}
if (RV) {
Builder.CreateRet(RV);
} else {
Builder.CreateRetVoid();
}
}
RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
llvm::Value *Callee,
const CallArgList &CallArgs,
const Decl *TargetDecl) {
// FIXME: We no longer need the types from CallArgs; lift up and
// simplify.
llvm::SmallVector<llvm::Value*, 16> Args;
// Handle struct-return functions by passing a pointer to the
// location that we would like to return into.
QualType RetTy = CallInfo.getReturnType();
const ABIArgInfo &RetAI = CallInfo.getReturnInfo();
if (CGM.ReturnTypeUsesSret(CallInfo)) {
// Create a temporary alloca to hold the result of the call. :(
Args.push_back(CreateTempAlloca(ConvertTypeForMem(RetTy)));
}
assert(CallInfo.arg_size() == CallArgs.size() &&
"Mismatch between function signature & arguments.");
CGFunctionInfo::const_arg_iterator info_it = CallInfo.arg_begin();
for (CallArgList::const_iterator I = CallArgs.begin(), E = CallArgs.end();
I != E; ++I, ++info_it) {
const ABIArgInfo &ArgInfo = info_it->info;
RValue RV = I->first;
switch (ArgInfo.getKind()) {
case ABIArgInfo::Indirect:
if (RV.isScalar() || RV.isComplex()) {
// Make a temporary alloca to pass the argument.
Args.push_back(CreateTempAlloca(ConvertTypeForMem(I->second)));
if (RV.isScalar())
EmitStoreOfScalar(RV.getScalarVal(), Args.back(), false);
else
StoreComplexToAddr(RV.getComplexVal(), Args.back(), false);
} else {
Args.push_back(RV.getAggregateAddr());
}
break;
case ABIArgInfo::Direct:
if (RV.isScalar()) {
Args.push_back(RV.getScalarVal());
} else if (RV.isComplex()) {
llvm::Value *Tmp = llvm::UndefValue::get(ConvertType(I->second));
Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().first, 0);
Tmp = Builder.CreateInsertValue(Tmp, RV.getComplexVal().second, 1);
Args.push_back(Tmp);
} else {
Args.push_back(Builder.CreateLoad(RV.getAggregateAddr()));
}
break;
case ABIArgInfo::Ignore:
break;
case ABIArgInfo::Coerce: {
// FIXME: Avoid the conversion through memory if possible.
llvm::Value *SrcPtr;
if (RV.isScalar()) {
SrcPtr = CreateTempAlloca(ConvertTypeForMem(I->second), "coerce");
EmitStoreOfScalar(RV.getScalarVal(), SrcPtr, false);
} else if (RV.isComplex()) {
SrcPtr = CreateTempAlloca(ConvertTypeForMem(I->second), "coerce");
StoreComplexToAddr(RV.getComplexVal(), SrcPtr, false);
} else
SrcPtr = RV.getAggregateAddr();
Args.push_back(CreateCoercedLoad(SrcPtr, ArgInfo.getCoerceToType(),
*this));
break;
}
case ABIArgInfo::Expand:
ExpandTypeToArgs(I->second, RV, Args);
break;
}
}
llvm::BasicBlock *InvokeDest = getInvokeDest();
CodeGen::AttributeListType AttributeList;
CGM.ConstructAttributeList(CallInfo, TargetDecl, AttributeList);
llvm::AttrListPtr Attrs = llvm::AttrListPtr::get(AttributeList.begin(),
AttributeList.end());
llvm::CallSite CS;
if (!InvokeDest || (Attrs.getFnAttributes() & llvm::Attribute::NoUnwind)) {
CS = Builder.CreateCall(Callee, &Args[0], &Args[0]+Args.size());
} else {
llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
CS = Builder.CreateInvoke(Callee, Cont, InvokeDest,
&Args[0], &Args[0]+Args.size());
EmitBlock(Cont);
}
CS.setAttributes(Attrs);
if (const llvm::Function *F = dyn_cast<llvm::Function>(Callee))
CS.setCallingConv(F->getCallingConv());
// If the call doesn't return, finish the basic block and clear the
// insertion point; this allows the rest of IRgen to discard
// unreachable code.
if (CS.doesNotReturn()) {
Builder.CreateUnreachable();
Builder.ClearInsertionPoint();
// FIXME: For now, emit a dummy basic block because expr
// emitters in generally are not ready to handle emitting
// expressions at unreachable points.
EnsureInsertPoint();
// Return a reasonable RValue.
return GetUndefRValue(RetTy);
}
llvm::Instruction *CI = CS.getInstruction();
if (Builder.isNamePreserving() && CI->getType() != llvm::Type::VoidTy)
CI->setName("call");
switch (RetAI.getKind()) {
case ABIArgInfo::Indirect:
if (RetTy->isAnyComplexType())
return RValue::getComplex(LoadComplexFromAddr(Args[0], false));
if (CodeGenFunction::hasAggregateLLVMType(RetTy))
return RValue::getAggregate(Args[0]);
return RValue::get(EmitLoadOfScalar(Args[0], false, RetTy));
case ABIArgInfo::Direct:
if (RetTy->isAnyComplexType()) {
llvm::Value *Real = Builder.CreateExtractValue(CI, 0);
llvm::Value *Imag = Builder.CreateExtractValue(CI, 1);
return RValue::getComplex(std::make_pair(Real, Imag));
}
if (CodeGenFunction::hasAggregateLLVMType(RetTy)) {
llvm::Value *V = CreateTempAlloca(ConvertTypeForMem(RetTy), "agg.tmp");
Builder.CreateStore(CI, V);
return RValue::getAggregate(V);
}
return RValue::get(CI);
case ABIArgInfo::Ignore:
// If we are ignoring an argument that had a result, make sure to
// construct the appropriate return value for our caller.
return GetUndefRValue(RetTy);
case ABIArgInfo::Coerce: {
// FIXME: Avoid the conversion through memory if possible.
llvm::Value *V = CreateTempAlloca(ConvertTypeForMem(RetTy), "coerce");
CreateCoercedStore(CI, V, *this);
if (RetTy->isAnyComplexType())
return RValue::getComplex(LoadComplexFromAddr(V, false));
if (CodeGenFunction::hasAggregateLLVMType(RetTy))
return RValue::getAggregate(V);
return RValue::get(EmitLoadOfScalar(V, false, RetTy));
}
case ABIArgInfo::Expand:
assert(0 && "Invalid ABI kind for return argument");
}
assert(0 && "Unhandled ABIArgInfo::Kind");
return RValue::get(0);
}
/* VarArg handling */
llvm::Value *CodeGenFunction::EmitVAArg(llvm::Value *VAListAddr, QualType Ty) {
return CGM.getTypes().getABIInfo().EmitVAArg(VAListAddr, Ty, *this);
}
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