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Add CodeGen support for functions that always return arguments via a new parameter attribute 'returned', which is taken advantage of in target-independent tail call opportunity detection and in ARM call lowering (when placed on an integral first parameter). 

llvm-svn: 179925
This commit is contained in:
Stephen Lin 2013-04-20 05:14:40 +00:00
parent ffc445492c
commit b8bd232a3d
20 changed files with 371 additions and 43 deletions
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12
llvm/docs/LangRef.rst
View File

@ -719,7 +719,17 @@ Currently, only the following parameter attributes are defined:
``nest``
This indicates that the pointer parameter can be excised using the
:ref:`trampoline intrinsics <int_trampoline>`. This is not a valid
attribute for return values.
attribute for return values and can only be applied to one parameter.
``returned``
This indicates that the value of the function always returns the value
of the parameter as its return value. This is an optimization hint to
the code generator when generating the caller, allowing tail call
optimization and omission of register saves and restores in some cases;
it is not checked or enforced when generating the callee. The parameter
and the function return type must be valid operands for the
:ref:`bitcast instruction <i_bitcast>`. This is not a valid attribute for
return values and can only be applied to one parameter.
.. _gc:

4
llvm/include/llvm/IR/Argument.h
View File

@ -78,6 +78,10 @@ public:
/// containing function.
bool hasStructRetAttr() const;
/// \brief Return true if this argument has the returned attribute on it in
/// its containing function.
bool hasReturnedAttr() const;
/// \brief Add a Attribute to an argument.
void addAttr(AttributeSet AS);

1
llvm/include/llvm/IR/Attributes.h
View File

@ -87,6 +87,7 @@ public:
OptimizeForSize, ///< opt_size
ReadNone, ///< Function does not access memory
ReadOnly, ///< Function only reads from memory
Returned, ///< Return value is always equal to this argument
ReturnsTwice, ///< Function can return twice
SExt, ///< Sign extended before/after call
StackAlignment, ///< Alignment of stack for function (3 bits)

37
llvm/include/llvm/Target/TargetCallingConv.h
View File

@ -36,10 +36,12 @@ namespace ISD {
static const uint64_t ByValOffs = 4;
static const uint64_t Nest = 1ULL<<5; ///< Nested fn static chain
static const uint64_t NestOffs = 5;
static const uint64_t ByValAlign = 0xFULL << 6; ///< Struct alignment
static const uint64_t ByValAlignOffs = 6;
static const uint64_t Split = 1ULL << 10;
static const uint64_t SplitOffs = 10;
static const uint64_t Returned = 1ULL<<6;
static const uint64_t ReturnedOffs = 6;
static const uint64_t ByValAlign = 0xFULL<<7; ///< Struct alignment
static const uint64_t ByValAlignOffs = 7;
static const uint64_t Split = 1ULL<<11;
static const uint64_t SplitOffs = 11;
static const uint64_t OrigAlign = 0x1FULL<<27;
static const uint64_t OrigAlignOffs = 27;
static const uint64_t ByValSize = 0xffffffffULL << 32; ///< Struct size
@ -51,23 +53,26 @@ namespace ISD {
public:
ArgFlagsTy() : Flags(0) { }
bool isZExt() const { return Flags & ZExt; }
void setZExt() { Flags |= One << ZExtOffs; }
bool isZExt() const { return Flags & ZExt; }
void setZExt() { Flags |= One << ZExtOffs; }
bool isSExt() const { return Flags & SExt; }
void setSExt() { Flags |= One << SExtOffs; }
bool isSExt() const { return Flags & SExt; }
void setSExt() { Flags |= One << SExtOffs; }
bool isInReg() const { return Flags & InReg; }
void setInReg() { Flags |= One << InRegOffs; }
bool isInReg() const { return Flags & InReg; }
void setInReg() { Flags |= One << InRegOffs; }
bool isSRet() const { return Flags & SRet; }
void setSRet() { Flags |= One << SRetOffs; }
bool isSRet() const { return Flags & SRet; }
void setSRet() { Flags |= One << SRetOffs; }
bool isByVal() const { return Flags & ByVal; }
void setByVal() { Flags |= One << ByValOffs; }
bool isByVal() const { return Flags & ByVal; }
void setByVal() { Flags |= One << ByValOffs; }
bool isNest() const { return Flags & Nest; }
void setNest() { Flags |= One << NestOffs; }
bool isNest() const { return Flags & Nest; }
void setNest() { Flags |= One << NestOffs; }
bool isReturned() const { return Flags & Returned; }
void setReturned() { Flags |= One << ReturnedOffs; }
unsigned getByValAlign() const {
return (unsigned)

16
llvm/include/llvm/Target/TargetLowering.h
View File

@ -1910,16 +1910,18 @@ public:
struct ArgListEntry {
SDValue Node;
Type* Ty;
bool isSExt : 1;
bool isZExt : 1;
bool isInReg : 1;
bool isSRet : 1;
bool isNest : 1;
bool isByVal : 1;
bool isSExt : 1;
bool isZExt : 1;
bool isInReg : 1;
bool isSRet : 1;
bool isNest : 1;
bool isByVal : 1;
bool isReturned : 1;
uint16_t Alignment;
ArgListEntry() : isSExt(false), isZExt(false), isInReg(false),
isSRet(false), isNest(false), isByVal(false), Alignment(0) { }
isSRet(false), isNest(false), isByVal(false), isReturned(false),
Alignment(0) { }
};
typedef std::vector<ArgListEntry> ArgListTy;

1
llvm/lib/AsmParser/LLLexer.cpp
View File

@ -582,6 +582,7 @@ lltok::Kind LLLexer::LexIdentifier() {
KEYWORD(optsize);
KEYWORD(readnone);
KEYWORD(readonly);
KEYWORD(returned);
KEYWORD(returns_twice);
KEYWORD(signext);
KEYWORD(sret);

3
llvm/lib/AsmParser/LLParser.cpp
View File

@ -944,6 +944,7 @@ bool LLParser::ParseFnAttributeValuePairs(AttrBuilder &B,
case lltok::kw_nest:
case lltok::kw_noalias:
case lltok::kw_nocapture:
case lltok::kw_returned:
case lltok::kw_sret:
HaveError |=
Error(Lex.getLoc(),
@ -1156,6 +1157,7 @@ bool LLParser::ParseOptionalParamAttrs(AttrBuilder &B) {
case lltok::kw_nest: B.addAttribute(Attribute::Nest); break;
case lltok::kw_noalias: B.addAttribute(Attribute::NoAlias); break;
case lltok::kw_nocapture: B.addAttribute(Attribute::NoCapture); break;
case lltok::kw_returned: B.addAttribute(Attribute::Returned); break;
case lltok::kw_signext: B.addAttribute(Attribute::SExt); break;
case lltok::kw_sret: B.addAttribute(Attribute::StructRet); break;
case lltok::kw_zeroext: B.addAttribute(Attribute::ZExt); break;
@ -1199,6 +1201,7 @@ bool LLParser::ParseOptionalReturnAttrs(AttrBuilder &B) {
case lltok::kw_byval:
case lltok::kw_nest:
case lltok::kw_nocapture:
case lltok::kw_returned:
case lltok::kw_sret:
HaveError |= Error(Lex.getLoc(), "invalid use of parameter-only attribute");
break;

1
llvm/lib/AsmParser/LLToken.h
View File

@ -114,6 +114,7 @@ namespace lltok {
kw_optsize,
kw_readnone,
kw_readonly,
kw_returned,
kw_returns_twice,
kw_signext,
kw_ssp,

26
llvm/lib/CodeGen/Analysis.cpp
View File

@ -261,6 +261,32 @@ static bool sameNoopInput(const Value *V1, const Value *V2,
TLI.getPointerTy().getSizeInBits() ==
cast<IntegerType>(I->getType())->getBitWidth())
NoopInput = Op;
} else if (isa<CallInst>(I)) {
// Look through call
for (User::const_op_iterator i = I->op_begin(),
// Skip Callee
e = I->op_end() - 1;
i != e; ++i) {
unsigned attrInd = i - I->op_begin() + 1;
if (cast<CallInst>(I)->paramHasAttr(attrInd, Attribute::Returned) &&
isNoopBitcast((*i)->getType(), I->getType(), TLI)) {
NoopInput = *i;
break;
}
}
} else if (isa<InvokeInst>(I)) {
// Look through invoke
for (User::const_op_iterator i = I->op_begin(),
// Skip BB, BB, Callee
e = I->op_end() - 3;
i != e; ++i) {
unsigned attrInd = i - I->op_begin() + 1;
if (cast<InvokeInst>(I)->paramHasAttr(attrInd, Attribute::Returned) &&
isNoopBitcast((*i)->getType(), I->getType(), TLI)) {
NoopInput = *i;
break;
}
}
}
}

18
llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
View File

@ -5232,6 +5232,7 @@ void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
Entry.isSRet = true;
Entry.isNest = false;
Entry.isByVal = false;
Entry.isReturned = false;
Entry.Alignment = Align;
Args.push_back(Entry);
RetTy = Type::getVoidTy(FTy->getContext());
@ -5249,13 +5250,14 @@ void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
Entry.Node = ArgNode; Entry.Ty = V->getType();
unsigned attrInd = i - CS.arg_begin() + 1;
Entry.isSExt = CS.paramHasAttr(attrInd, Attribute::SExt);
Entry.isZExt = CS.paramHasAttr(attrInd, Attribute::ZExt);
Entry.isInReg = CS.paramHasAttr(attrInd, Attribute::InReg);
Entry.isSRet = CS.paramHasAttr(attrInd, Attribute::StructRet);
Entry.isNest = CS.paramHasAttr(attrInd, Attribute::Nest);
Entry.isByVal = CS.paramHasAttr(attrInd, Attribute::ByVal);
Entry.Alignment = CS.getParamAlignment(attrInd);
Entry.isSExt = CS.paramHasAttr(attrInd, Attribute::SExt);
Entry.isZExt = CS.paramHasAttr(attrInd, Attribute::ZExt);
Entry.isInReg = CS.paramHasAttr(attrInd, Attribute::InReg);
Entry.isSRet = CS.paramHasAttr(attrInd, Attribute::StructRet);
Entry.isNest = CS.paramHasAttr(attrInd, Attribute::Nest);
Entry.isByVal = CS.paramHasAttr(attrInd, Attribute::ByVal);
Entry.isReturned = CS.paramHasAttr(attrInd, Attribute::Returned);
Entry.Alignment = CS.getParamAlignment(attrInd);
Args.push_back(Entry);
}
@ -6430,6 +6432,8 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
}
if (Args[i].isNest)
Flags.setNest();
if (Args[i].isReturned)
Flags.setReturned();
Flags.setOrigAlign(OriginalAlignment);
MVT PartVT = getRegisterType(CLI.RetTy->getContext(), VT);

3
llvm/lib/IR/Attributes.cpp
View File

@ -195,6 +195,8 @@ std::string Attribute::getAsString(bool InAttrGrp) const {
return "readnone";
if (hasAttribute(Attribute::ReadOnly))
return "readonly";
if (hasAttribute(Attribute::Returned))
return "returned";
if (hasAttribute(Attribute::ReturnsTwice))
return "returns_twice";
if (hasAttribute(Attribute::SExt))
@ -393,6 +395,7 @@ uint64_t AttributeImpl::getAttrMask(Attribute::AttrKind Val) {
case Attribute::SanitizeThread: return 1ULL << 36;
case Attribute::SanitizeMemory: return 1ULL << 37;
case Attribute::NoBuiltin: return 1ULL << 38;
case Attribute::Returned: return 1ULL << 39;
}
llvm_unreachable("Unsupported attribute type");
}

7
llvm/lib/IR/Function.cpp
View File

@ -124,6 +124,13 @@ bool Argument::hasStructRetAttr() const {
hasAttribute(1, Attribute::StructRet);
}
/// hasReturnedAttr - Return true if this argument has the returned attribute on
/// it in its containing function.
bool Argument::hasReturnedAttr() const {
return getParent()->getAttributes().
hasAttribute(getArgNo()+1, Attribute::Returned);
}
/// addAttr - Add attributes to an argument.
void Argument::addAttr(AttributeSet AS) {
assert(AS.getNumSlots() <= 1 &&

51
llvm/lib/IR/Verifier.cpp
View File

@ -694,8 +694,9 @@ void Verifier::VerifyParameterAttrs(AttributeSet Attrs, unsigned Idx, Type *Ty,
Assert1(!Attrs.hasAttribute(Idx, Attribute::ByVal) &&
!Attrs.hasAttribute(Idx, Attribute::Nest) &&
!Attrs.hasAttribute(Idx, Attribute::StructRet) &&
!Attrs.hasAttribute(Idx, Attribute::NoCapture),
"Attribute 'byval', 'nest', 'sret', and 'nocapture' "
!Attrs.hasAttribute(Idx, Attribute::NoCapture) &&
!Attrs.hasAttribute(Idx, Attribute::Returned),
"Attribute 'byval', 'nest', 'sret', 'nocapture', and 'returned' "
"do not apply to return values!", V);
// Check for mutually incompatible attributes.
@ -750,6 +751,7 @@ void Verifier::VerifyFunctionAttrs(FunctionType *FT, AttributeSet Attrs,
return;
bool SawNest = false;
bool SawReturned = false;
for (unsigned i = 0, e = Attrs.getNumSlots(); i != e; ++i) {
unsigned Idx = Attrs.getSlotIndex(i);
@ -764,11 +766,22 @@ void Verifier::VerifyFunctionAttrs(FunctionType *FT, AttributeSet Attrs,
VerifyParameterAttrs(Attrs, Idx, Ty, Idx == 0, V);
if (Attrs.hasAttribute(i, Attribute::Nest)) {
if (Idx == 0)
continue;
if (Attrs.hasAttribute(Idx, Attribute::Nest)) {
Assert1(!SawNest, "More than one parameter has attribute nest!", V);
SawNest = true;
}
if (Attrs.hasAttribute(Idx, Attribute::Returned)) {
Assert1(!SawReturned, "More than one parameter has attribute returned!",
V);
Assert1(Ty->canLosslesslyBitCastTo(FT->getReturnType()), "Incompatible "
"argument and return types for 'returned' attribute", V);
SawReturned = true;
}
if (Attrs.hasAttribute(Idx, Attribute::StructRet))
Assert1(Idx == 1, "Attribute sret is not on first parameter!", V);
}
@ -1348,15 +1361,41 @@ void Verifier::VerifyCallSite(CallSite CS) {
// Verify call attributes.
VerifyFunctionAttrs(FTy, Attrs, I);
if (FTy->isVarArg())
if (FTy->isVarArg()) {
// FIXME? is 'nest' even legal here?
bool SawNest = false;
bool SawReturned = false;
for (unsigned Idx = 1; Idx < 1 + FTy->getNumParams(); ++Idx) {
if (Attrs.hasAttribute(Idx, Attribute::Nest))
SawNest = true;
if (Attrs.hasAttribute(Idx, Attribute::Returned))
SawReturned = true;
}
// Check attributes on the varargs part.
for (unsigned Idx = 1 + FTy->getNumParams(); Idx <= CS.arg_size(); ++Idx) {
VerifyParameterAttrs(Attrs, Idx, CS.getArgument(Idx-1)->getType(),
false, I);
Type *Ty = CS.getArgument(Idx-1)->getType();
VerifyParameterAttrs(Attrs, Idx, Ty, false, I);
if (Attrs.hasAttribute(Idx, Attribute::Nest)) {
Assert1(!SawNest, "More than one parameter has attribute nest!", I);
SawNest = true;
}
if (Attrs.hasAttribute(Idx, Attribute::Returned)) {
Assert1(!SawReturned, "More than one parameter has attribute returned!",
I);
Assert1(Ty->canLosslesslyBitCastTo(FTy->getReturnType()),
"Incompatible argument and return types for 'returned' "
"attribute", I);
SawReturned = true;
}
Assert1(!Attrs.hasAttribute(Idx, Attribute::StructRet),
"Attribute 'sret' cannot be used for vararg call arguments!", I);
}
}
// Verify that there's no metadata unless it's a direct call to an intrinsic.
if (CS.getCalledFunction() == 0 ||

6
llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
View File

@ -74,6 +74,12 @@ ARMBaseRegisterInfo::getCallPreservedMask(CallingConv::ID) const {
? CSR_iOS_RegMask : CSR_AAPCS_RegMask;
}
const uint32_t*
ARMBaseRegisterInfo::getThisReturnPreservedMask(CallingConv::ID) const {
return (STI.isTargetIOS() && !STI.isAAPCS_ABI())
? CSR_iOS_ThisReturn_RegMask : CSR_AAPCS_ThisReturn_RegMask;
}
const uint32_t*
ARMBaseRegisterInfo::getNoPreservedMask() const {
return CSR_NoRegs_RegMask;

1
llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
View File

@ -96,6 +96,7 @@ public:
/// Code Generation virtual methods...
const uint16_t *getCalleeSavedRegs(const MachineFunction *MF = 0) const;
const uint32_t *getCallPreservedMask(CallingConv::ID) const;
const uint32_t *getThisReturnPreservedMask(CallingConv::ID) const;
const uint32_t *getNoPreservedMask() const;
BitVector getReservedRegs(const MachineFunction &MF) const;

11
llvm/lib/Target/ARM/ARMCallingConv.td
View File

@ -195,10 +195,21 @@ def CSR_NoRegs : CalleeSavedRegs<(add)>;
def CSR_AAPCS : CalleeSavedRegs<(add LR, R11, R10, R9, R8, R7, R6, R5, R4,
(sequence "D%u", 15, 8))>;
// Constructors and destructors return 'this' in the ARM C++ ABI; since 'this'
// and the pointer return value are both passed in R0 in these cases, this can
// be partially modelled by treating R0 as a callee-saved register
// Only the resulting RegMask is used; the SaveList is ignored
def CSR_AAPCS_ThisReturn : CalleeSavedRegs<(add LR, R11, R10, R9, R8, R7, R6,
R5, R4, (sequence "D%u", 15, 8),
R0)>;
// iOS ABI deviates from ARM standard ABI. R9 is not a callee-saved register.
// Also save R7-R4 first to match the stack frame fixed spill areas.
def CSR_iOS : CalleeSavedRegs<(add LR, R7, R6, R5, R4, (sub CSR_AAPCS, R9))>;
def CSR_iOS_ThisReturn : CalleeSavedRegs<(add LR, R7, R6, R5, R4,
(sub CSR_AAPCS_ThisReturn, R9))>;
// GHC set of callee saved regs is empty as all those regs are
// used for passing STG regs around
// add is a workaround for not being able to compile empty list:

33
llvm/lib/Target/ARM/ARMISelLowering.cpp
View File

@ -1238,7 +1238,8 @@ ARMTargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
SmallVectorImpl<SDValue> &InVals,
bool isThisReturn, SDValue ThisVal) const {
// Assign locations to each value returned by this call.
SmallVector<CCValAssign, 16> RVLocs;
@ -1252,6 +1253,14 @@ ARMTargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
for (unsigned i = 0; i != RVLocs.size(); ++i) {
CCValAssign VA = RVLocs[i];
// Pass 'this' value directly from the argument to return value, to avoid
// reg unit interference
if (i == 0 && isThisReturn) {
assert(!VA.needsCustom() && VA.getLocVT() == MVT::i32);
InVals.push_back(ThisVal);
continue;
}
SDValue Val;
if (VA.needsCustom()) {
// Handle f64 or half of a v2f64.
@ -1364,7 +1373,8 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
MachineFunction &MF = DAG.getMachineFunction();
bool IsStructRet = (Outs.empty()) ? false : Outs[0].Flags.isSRet();
bool IsSibCall = false;
bool IsThisReturn = false;
bool IsSibCall = false;
// Disable tail calls if they're not supported.
if (!EnableARMTailCalls && !Subtarget->supportsTailCall())
isTailCall = false;
@ -1460,6 +1470,11 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
StackPtr, MemOpChains, Flags);
}
} else if (VA.isRegLoc()) {
if (realArgIdx == 0 && Flags.isReturned() && VA.getLocVT() == MVT::i32) {
assert(!Ins.empty() && Ins[0].VT == Outs[0].VT &&
"unexpected use of 'returned'");
IsThisReturn = true;
}
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
} else if (isByVal) {
assert(VA.isMemLoc());
@ -1680,8 +1695,15 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
RegsToPass[i].second.getValueType()));
// Add a register mask operand representing the call-preserved registers.
const uint32_t *Mask;
const TargetRegisterInfo *TRI = getTargetMachine().getRegisterInfo();
const uint32_t *Mask = TRI->getCallPreservedMask(CallConv);
const ARMBaseRegisterInfo *ARI = static_cast<const ARMBaseRegisterInfo*>(TRI);
if (IsThisReturn)
// For 'this' returns, use the R0-preserving mask
Mask = ARI->getThisReturnPreservedMask(CallConv);
else
Mask = ARI->getCallPreservedMask(CallConv);
assert(Mask && "Missing call preserved mask for calling convention");
Ops.push_back(DAG.getRegisterMask(Mask));
@ -1703,8 +1725,9 @@ ARMTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
// Handle result values, copying them out of physregs into vregs that we
// return.
return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins,
dl, DAG, InVals);
return LowerCallResult(Chain, InFlag, CallConv, isVarArg, Ins, dl, DAG,
InVals, IsThisReturn,
IsThisReturn ? OutVals[0] : SDValue());
}
/// HandleByVal - Every parameter *after* a byval parameter is passed

3
llvm/lib/Target/ARM/ARMISelLowering.h
View File

@ -464,7 +464,8 @@ namespace llvm {
CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const;
SmallVectorImpl<SDValue> &InVals,
bool isThisReturn, SDValue ThisVal) const;
virtual SDValue
LowerFormalArguments(SDValue Chain,

91
llvm/test/CodeGen/ARM/this-return.ll Normal file
View File

@ -0,0 +1,91 @@
; RUN: llc < %s -mtriple=armv6-linux-gnueabi -arm-tail-calls | FileCheck %s -check-prefix=CHECKELF
; RUN: llc < %s -mtriple=thumbv7-apple-ios -arm-tail-calls | FileCheck %s -check-prefix=CHECKT2D
%struct.A = type { i8 }
%struct.B = type { i32 }
%struct.C = type { %struct.B }
%struct.D = type { %struct.B }
declare %struct.A* @A_ctor_base(%struct.A* returned)
declare %struct.B* @B_ctor_base(%struct.B* returned, i32)
declare %struct.B* @B_ctor_complete(%struct.B* returned, i32)
declare %struct.A* @A_ctor_base_nothisret(%struct.A*)
declare %struct.B* @B_ctor_base_nothisret(%struct.B*, i32)
declare %struct.B* @B_ctor_complete_nothisret(%struct.B*, i32)
define %struct.C* @C_ctor_base(%struct.C* returned %this, i32 %x) {
entry:
; CHECKELF: C_ctor_base:
; CHECKELF-NOT: mov {{r[0-9]+}}, r0
; CHECKELF: bl A_ctor_base
; CHECKELF-NOT: mov r0, {{r[0-9]+}}
; CHECKELF: b B_ctor_base
; CHECKT2D: C_ctor_base:
; CHECKT2D-NOT: mov {{r[0-9]+}}, r0
; CHECKT2D: blx _A_ctor_base
; CHECKT2D-NOT: mov r0, {{r[0-9]+}}
; CHECKT2D: b.w _B_ctor_base
%0 = bitcast %struct.C* %this to %struct.A*
%call = tail call %struct.A* @A_ctor_base(%struct.A* %0)
%1 = getelementptr inbounds %struct.C* %this, i32 0, i32 0
%call2 = tail call %struct.B* @B_ctor_base(%struct.B* %1, i32 %x)
ret %struct.C* %this
}
define %struct.C* @C_ctor_base_nothisret(%struct.C* %this, i32 %x) {
entry:
; CHECKELF: C_ctor_base_nothisret:
; CHECKELF: mov [[SAVETHIS:r[0-9]+]], r0
; CHECKELF: bl A_ctor_base_nothisret
; CHECKELF: mov r0, [[SAVETHIS]]
; CHECKELF-NOT: b B_ctor_base_nothisret
; CHECKT2D: C_ctor_base_nothisret:
; CHECKT2D: mov [[SAVETHIS:r[0-9]+]], r0
; CHECKT2D: blx _A_ctor_base_nothisret
; CHECKT2D: mov r0, [[SAVETHIS]]
; CHECKT2D-NOT: b.w _B_ctor_base_nothisret
%0 = bitcast %struct.C* %this to %struct.A*
%call = tail call %struct.A* @A_ctor_base_nothisret(%struct.A* %0)
%1 = getelementptr inbounds %struct.C* %this, i32 0, i32 0
%call2 = tail call %struct.B* @B_ctor_base_nothisret(%struct.B* %1, i32 %x)
ret %struct.C* %this
}
define %struct.C* @C_ctor_complete(%struct.C* %this, i32 %x) {
entry:
; CHECKELF: C_ctor_complete:
; CHECKELF: b C_ctor_base
; CHECKT2D: C_ctor_complete:
; CHECKT2D: b.w _C_ctor_base
%call = tail call %struct.C* @C_ctor_base(%struct.C* %this, i32 %x)
ret %struct.C* %this
}
define %struct.C* @C_ctor_complete_nothisret(%struct.C* %this, i32 %x) {
entry:
; CHECKELF: C_ctor_complete_nothisret:
; CHECKELF-NOT: b C_ctor_base_nothisret
; CHECKT2D: C_ctor_complete_nothisret:
; CHECKT2D-NOT: b.w _C_ctor_base_nothisret
%call = tail call %struct.C* @C_ctor_base_nothisret(%struct.C* %this, i32 %x)
ret %struct.C* %this
}
define %struct.D* @D_ctor_base(%struct.D* %this, i32 %x) {
entry:
; CHECKELF: D_ctor_base:
; CHECKELF-NOT: mov {{r[0-9]+}}, r0
; CHECKELF: bl B_ctor_complete
; CHECKELF-NOT: mov r0, {{r[0-9]+}}
; CHECKELF: b B_ctor_complete
; CHECKT2D: D_ctor_base:
; CHECKT2D-NOT: mov {{r[0-9]+}}, r0
; CHECKT2D: blx _B_ctor_complete
; CHECKT2D-NOT: mov r0, {{r[0-9]+}}
; CHECKT2D: b.w _B_ctor_complete
%b = getelementptr inbounds %struct.D* %this, i32 0, i32 0
%call = tail call %struct.B* @B_ctor_complete(%struct.B* %b, i32 %x)
%call2 = tail call %struct.B* @B_ctor_complete(%struct.B* %b, i32 %x)
ret %struct.D* %this
}

89
llvm/test/CodeGen/X86/this-return-64.ll Normal file
View File

@ -0,0 +1,89 @@
; RUN: llc < %s -mtriple=x86_64-pc-win32 | FileCheck %s
%struct.A = type { i8 }
%struct.B = type { i32 }
%struct.C = type { %struct.B }
%struct.D = type { %struct.B }
%struct.E = type { %struct.B }
declare %struct.A* @A_ctor(%struct.A* returned)
declare %struct.B* @B_ctor(%struct.B* returned, i32)
declare %struct.A* @A_ctor_nothisret(%struct.A*)
declare %struct.B* @B_ctor_nothisret(%struct.B*, i32)
define %struct.C* @C_ctor(%struct.C* %this, i32 %y) {
entry:
; CHECK: C_ctor:
; CHECK: jmp B_ctor # TAILCALL
%0 = getelementptr inbounds %struct.C* %this, i64 0, i32 0
%call = tail call %struct.B* @B_ctor(%struct.B* %0, i32 %y)
ret %struct.C* %this
}
define %struct.C* @C_ctor_nothisret(%struct.C* %this, i32 %y) {
entry:
; CHECK: C_ctor_nothisret:
; CHECK-NOT: jmp B_ctor_nothisret
%0 = getelementptr inbounds %struct.C* %this, i64 0, i32 0
%call = tail call %struct.B* @B_ctor_nothisret(%struct.B* %0, i32 %y)
ret %struct.C* %this
}
define %struct.D* @D_ctor(%struct.D* %this, i32 %y) {
entry:
; CHECK: D_ctor:
; CHECK: movq %rcx, [[SAVETHIS:%r[0-9a-z]+]]
; CHECK: callq A_ctor
; CHECK: movq [[SAVETHIS]], %rcx
; CHECK: jmp B_ctor # TAILCALL
%0 = bitcast %struct.D* %this to %struct.A*
%call = tail call %struct.A* @A_ctor(%struct.A* %0)
%1 = getelementptr inbounds %struct.D* %this, i64 0, i32 0
%call2 = tail call %struct.B* @B_ctor(%struct.B* %1, i32 %y)
; (this next line would never be generated by Clang, actually)
%2 = bitcast %struct.A* %call to %struct.D*
ret %struct.D* %2
}
define %struct.D* @D_ctor_nothisret(%struct.D* %this, i32 %y) {
entry:
; CHECK: D_ctor_nothisret:
; CHECK: movq %rcx, [[SAVETHIS:%r[0-9a-z]+]]
; CHECK: callq A_ctor_nothisret
; CHECK: movq [[SAVETHIS]], %rcx
; CHECK-NOT: jmp B_ctor_nothisret
%0 = bitcast %struct.D* %this to %struct.A*
%call = tail call %struct.A* @A_ctor_nothisret(%struct.A* %0)
%1 = getelementptr inbounds %struct.D* %this, i64 0, i32 0
%call2 = tail call %struct.B* @B_ctor_nothisret(%struct.B* %1, i32 %y)
; (this next line would never be generated by Clang, actually)
%2 = bitcast %struct.A* %call to %struct.D*
ret %struct.D* %2
}
define %struct.E* @E_ctor(%struct.E* %this, i32 %x) {
entry:
; CHECK: E_ctor:
; CHECK: movq %rcx, [[SAVETHIS:%r[0-9a-z]+]]
; CHECK: callq B_ctor
; CHECK: movq [[SAVETHIS]], %rcx
; CHECK: jmp B_ctor # TAILCALL
%b = getelementptr inbounds %struct.E* %this, i64 0, i32 0
%call = tail call %struct.B* @B_ctor(%struct.B* %b, i32 %x)
%call4 = tail call %struct.B* @B_ctor(%struct.B* %b, i32 %x)
ret %struct.E* %this
}
define %struct.E* @E_ctor_nothisret(%struct.E* %this, i32 %x) {
entry:
; CHECK: E_ctor_nothisret:
; CHECK: movq %rcx, [[SAVETHIS:%r[0-9a-z]+]]
; CHECK: callq B_ctor_nothisret
; CHECK: movq [[SAVETHIS]], %rcx
; CHECK-NOT: jmp B_ctor_nothisret
%b = getelementptr inbounds %struct.E* %this, i64 0, i32 0
%call = tail call %struct.B* @B_ctor_nothisret(%struct.B* %b, i32 %x)
%call4 = tail call %struct.B* @B_ctor_nothisret(%struct.B* %b, i32 %x)
ret %struct.E* %this
}