//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mips-lower"
+//#include <algorithm>
#include "MipsISelLowering.h"
#include "MipsMachineFunction.h"
#include "MipsTargetMachine.h"
SDValue MipsTargetLowering::
LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const
{
+ unsigned StackAlignment =
+ getTargetMachine().getFrameLowering()->getStackAlignment();
+ assert(StackAlignment >=
+ cast<ConstantSDNode>(Op.getOperand(2).getNode())->getZExtValue() &&
+ "Cannot lower if the alignment of the allocated space is larger than \
+ that of the stack.");
+
SDValue Chain = Op.getOperand(0);
SDValue Size = Op.getOperand(1);
DebugLoc dl = Op.getDebugLoc();
// The Sub result contains the new stack start address, so it
// must be placed in the stack pointer register.
- Chain = DAG.getCopyToReg(StackPointer.getValue(1), dl, Mips::SP, Sub);
+ Chain = DAG.getCopyToReg(StackPointer.getValue(1), dl, Mips::SP, Sub,
+ SDValue());
+ // Retrieve updated $sp. There is a glue input to prevent instructions that
+ // clobber $sp from being inserted between copytoreg and copyfromreg.
+ SDValue NewSP = DAG.getCopyFromReg(Chain, dl, Mips::SP, MVT::i32,
+ Chain.getValue(1));
+
+ // The stack space reserved by alloca is located right above the argument
+ // area. It is aligned on a boundary that is a multiple of StackAlignment.
+ MachineFunction &MF = DAG.getMachineFunction();
+ MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
+ unsigned SPOffset = (MipsFI->getMaxCallFrameSize() + StackAlignment - 1) /
+ StackAlignment * StackAlignment;
+ SDValue AllocPtr = DAG.getNode(ISD::ADD, dl, MVT::i32, NewSP,
+ DAG.getConstant(SPOffset, MVT::i32));
// This node always has two return values: a new stack pointer
// value and a chain
- SDValue Ops[2] = { Sub, Chain };
+ SDValue Ops[2] = { AllocPtr, NewSP.getValue(1) };
return DAG.getMergeValues(Ops, 2, dl);
}
Mips::D6, Mips::D7
};
+ // ByVal Args
+ if (ArgFlags.isByVal()) {
+ State.HandleByVal(ValNo, ValVT, LocVT, LocInfo,
+ 1 /*MinSize*/, 4 /*MinAlign*/, ArgFlags);
+ unsigned NextReg = (State.getNextStackOffset() + 3) / 4;
+ for (unsigned r = State.getFirstUnallocated(IntRegs, IntRegsSize);
+ r < std::min(IntRegsSize, NextReg); ++r)
+ State.AllocateReg(IntRegs[r]);
+ return false;
+ }
+
// Promote i8 and i16
if (LocVT == MVT::i8 || LocVT == MVT::i16) {
LocVT = MVT::i32;
// Call Calling Convention Implementation
//===----------------------------------------------------------------------===//
+static const unsigned O32IntRegsSize = 4;
+
+static const unsigned O32IntRegs[] = {
+ Mips::A0, Mips::A1, Mips::A2, Mips::A3
+};
+
+// Write ByVal Arg to arg registers and stack.
+static void
+WriteByValArg(SDValue& Chain, DebugLoc dl,
+ SmallVector<std::pair<unsigned, SDValue>, 16>& RegsToPass,
+ SmallVector<SDValue, 8>& MemOpChains, int& LastFI,
+ MachineFrameInfo *MFI, SelectionDAG &DAG, SDValue Arg,
+ const CCValAssign &VA, const ISD::ArgFlagsTy& Flags,
+ MVT PtrType) {
+ unsigned FirstWord = VA.getLocMemOffset() / 4;
+ unsigned NumWords = (Flags.getByValSize() + 3) / 4;
+ unsigned LastWord = FirstWord + NumWords;
+ unsigned CurWord;
+
+ // copy the first 4 words of byval arg to registers A0 - A3
+ for (CurWord = FirstWord; CurWord < std::min(LastWord, O32IntRegsSize);
+ ++CurWord) {
+ SDValue LoadPtr = DAG.getNode(ISD::ADD, dl, MVT::i32, Arg,
+ DAG.getConstant((CurWord - FirstWord) * 4,
+ MVT::i32));
+ SDValue LoadVal = DAG.getLoad(MVT::i32, dl, Chain, LoadPtr,
+ MachinePointerInfo(),
+ false, false, 0);
+ MemOpChains.push_back(LoadVal.getValue(1));
+ unsigned DstReg = O32IntRegs[CurWord];
+ RegsToPass.push_back(std::make_pair(DstReg, LoadVal));
+ }
+
+ // copy remaining part of byval arg to stack.
+ if (CurWord < LastWord) {
+ unsigned SizeInBytes = (LastWord - CurWord) * 4;
+ SDValue Src = DAG.getNode(ISD::ADD, dl, MVT::i32, Arg,
+ DAG.getConstant((CurWord - FirstWord) * 4,
+ MVT::i32));
+ LastFI = MFI->CreateFixedObject(SizeInBytes, CurWord * 4, true);
+ SDValue Dst = DAG.getFrameIndex(LastFI, PtrType);
+ Chain = DAG.getMemcpy(Chain, dl, Dst, Src,
+ DAG.getConstant(SizeInBytes, MVT::i32),
+ /*Align*/4,
+ /*isVolatile=*/false, /*AlwaysInline=*/false,
+ MachinePointerInfo(0), MachinePointerInfo(0));
+ MemOpChains.push_back(Chain);
+ }
+}
+
/// LowerCall - functions arguments are copied from virtual regs to
/// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
/// TODO: isTailCall.
// With EABI is it possible to have 16 args on registers.
SmallVector<std::pair<unsigned, SDValue>, 16> RegsToPass;
SmallVector<SDValue, 8> MemOpChains;
- unsigned NextStackOffset = (Subtarget->isABI_EABI() ? 0 : 16);
MipsFI->setHasCall();
- // Create GP frame object if this is the first call.
- // SPOffset will be updated after call frame size is known.
+ // If this is the first call, create a stack frame object that points to
+ // a location to which .cprestore saves $gp. The offset of this frame object
+ // is set to 0, since we know nothing about the size of the argument area at
+ // this point.
if (IsPIC && !MipsFI->getGPFI())
MipsFI->setGPFI(MFI->CreateFixedObject(4, 0, true));
// Register can't get to this point...
assert(VA.isMemLoc());
- // Create the frame index object for this incoming parameter
- // This guarantees that when allocating Local Area the firsts
- // 16 bytes which are alwayes reserved won't be overwritten
- // if O32 ABI is used. For EABI the first address is zero.
- unsigned ArgSize = VA.getValVT().getSizeInBits()/8;
- NextStackOffset = VA.getLocMemOffset();
- LastFI = MFI->CreateFixedObject(ArgSize, NextStackOffset, true);
- NextStackOffset += ArgSize;
+ // ByVal Arg.
+ ISD::ArgFlagsTy Flags = Outs[i].Flags;
+ if (Flags.isByVal()) {
+ assert(Subtarget->isABI_O32() &&
+ "No support for ByVal args by ABIs other than O32 yet.");
+ assert(Flags.getByValSize() &&
+ "ByVal args of size 0 should have been ignored by front-end.");
+ WriteByValArg(Chain, dl, RegsToPass, MemOpChains, LastFI, MFI, DAG, Arg,
+ VA, Flags, getPointerTy());
+ continue;
+ }
+ // Create the frame index object for this incoming parameter
+ LastFI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8,
+ VA.getLocMemOffset(), true);
SDValue PtrOff = DAG.getFrameIndex(LastFI, getPointerTy());
// emit ISD::STORE whichs stores the
Chain = DAG.getNode(MipsISD::JmpLink, dl, NodeTys, &Ops[0], Ops.size());
InFlag = Chain.getValue(1);
- // Create a stack location to hold GP when PIC is used. This stack
- // location is used on function prologue to save GP and also after all
- // emitted CALL's to restore GP.
if (IsPIC) {
// Function can have an arbitrary number of calls, so
// hold the LastArgStackLoc with the biggest offset.
int MaxCallFrameSize = MipsFI->getMaxCallFrameSize();
+ unsigned NextStackOffset = CCInfo.getNextStackOffset();
+
+ // For O32, a minimum of four words (16 bytes) of argument space is
+ // allocated.
+ if (Subtarget->isABI_O32())
+ NextStackOffset = std::max(NextStackOffset, (unsigned)16);
if (MaxCallFrameSize < (int)NextStackOffset) {
MipsFI->setMaxCallFrameSize(NextStackOffset);
//===----------------------------------------------------------------------===//
// Formal Arguments Calling Convention Implementation
//===----------------------------------------------------------------------===//
+static void ReadByValArg(MachineFunction &MF, SDValue Chain, DebugLoc dl,
+ std::vector<SDValue>& OutChains,
+ SelectionDAG &DAG, unsigned NumWords, SDValue FIN,
+ const CCValAssign &VA, const ISD::ArgFlagsTy& Flags) {
+ unsigned LocMem = VA.getLocMemOffset();
+ unsigned FirstWord = LocMem / 4;
+
+ // copy register A0 - A3 to frame object
+ for (unsigned i = 0; i < NumWords; ++i) {
+ unsigned CurWord = FirstWord + i;
+ if (CurWord >= O32IntRegsSize)
+ break;
+
+ unsigned SrcReg = O32IntRegs[CurWord];
+ unsigned Reg = AddLiveIn(MF, SrcReg, Mips::CPURegsRegisterClass);
+ SDValue StorePtr = DAG.getNode(ISD::ADD, dl, MVT::i32, FIN,
+ DAG.getConstant(i * 4, MVT::i32));
+ SDValue Store = DAG.getStore(Chain, dl, DAG.getRegister(Reg, MVT::i32),
+ StorePtr, MachinePointerInfo(), false,
+ false, 0);
+ OutChains.push_back(Store);
+ }
+}
/// LowerFormalArguments - transform physical registers into virtual registers
/// and generate load operations for arguments places on the stack.
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals)
const {
-
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
// Used with vargs to acumulate store chains.
std::vector<SDValue> OutChains;
- // Keep track of the last register used for arguments
- unsigned ArgRegEnd = 0;
-
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
else
CCInfo.AnalyzeFormalArguments(Ins, CC_Mips);
- unsigned NextStackOffset = (Subtarget->isABI_EABI() ? 0 : 16);
- EVT LastRegArgValVT;
int LastFI = 0;// MipsFI->LastInArgFI is 0 at the entry of this function.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
// Arguments stored on registers
if (VA.isRegLoc()) {
EVT RegVT = VA.getLocVT();
- ArgRegEnd = VA.getLocReg();
- LastRegArgValVT = VA.getValVT();
+ unsigned ArgReg = VA.getLocReg();
TargetRegisterClass *RC = 0;
if (RegVT == MVT::i32)
// Transform the arguments stored on
// physical registers into virtual ones
- unsigned Reg = AddLiveIn(DAG.getMachineFunction(), ArgRegEnd, RC);
+ unsigned Reg = AddLiveIn(DAG.getMachineFunction(), ArgReg, RC);
SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, RegVT);
// If this is an 8 or 16-bit value, it has been passed promoted
// sanity check
assert(VA.isMemLoc());
- // The last argument is not a register anymore
- ArgRegEnd = 0;
+ ISD::ArgFlagsTy Flags = Ins[i].Flags;
+
+ if (Flags.isByVal()) {
+ assert(Subtarget->isABI_O32() &&
+ "No support for ByVal args by ABIs other than O32 yet.");
+ assert(Flags.getByValSize() &&
+ "ByVal args of size 0 should have been ignored by front-end.");
+ unsigned NumWords = (Flags.getByValSize() + 3) / 4;
+ LastFI = MFI->CreateFixedObject(NumWords * 4, VA.getLocMemOffset(),
+ true);
+ SDValue FIN = DAG.getFrameIndex(LastFI, getPointerTy());
+ InVals.push_back(FIN);
+ ReadByValArg(MF, Chain, dl, OutChains, DAG, NumWords, FIN, VA, Flags);
+
+ continue;
+ }
// The stack pointer offset is relative to the caller stack frame.
- // Since the real stack size is unknown here, a negative SPOffset
- // is used so there's a way to adjust these offsets when the stack
- // size get known (on EliminateFrameIndex). A dummy SPOffset is
- // used instead of a direct negative address (which is recorded to
- // be used on emitPrologue) to avoid mis-calc of the first stack
- // offset on PEI::calculateFrameObjectOffsets.
- unsigned ArgSize = VA.getValVT().getSizeInBits()/8;
- NextStackOffset = VA.getLocMemOffset();
- LastFI = MFI->CreateFixedObject(ArgSize, NextStackOffset, true);
- NextStackOffset += ArgSize;
+ LastFI = MFI->CreateFixedObject(VA.getValVT().getSizeInBits()/8,
+ VA.getLocMemOffset(), true);
// Create load nodes to retrieve arguments from the stack
SDValue FIN = DAG.getFrameIndex(LastFI, getPointerTy());
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Copy, Chain);
}
- // To meet ABI, when VARARGS are passed on registers, the registers
- // must have their values written to the caller stack frame. If the last
- // argument was placed in the stack, there's no need to save any register.
if (isVarArg && Subtarget->isABI_O32()) {
- if (ArgRegEnd) {
- // Last named formal argument is passed in register.
-
- // The last register argument that must be saved is Mips::A3
+ // Record the frame index of the first variable argument
+ // which is a value necessary to VASTART.
+ unsigned NextStackOffset = CCInfo.getNextStackOffset();
+ assert(NextStackOffset % 4 == 0 &&
+ "NextStackOffset must be aligned to 4-byte boundaries.");
+ LastFI = MFI->CreateFixedObject(4, NextStackOffset, true);
+ MipsFI->setVarArgsFrameIndex(LastFI);
+
+ // If NextStackOffset is smaller than o32's 16-byte reserved argument area,
+ // copy the integer registers that have not been used for argument passing
+ // to the caller's stack frame.
+ for (; NextStackOffset < 16; NextStackOffset += 4) {
TargetRegisterClass *RC = Mips::CPURegsRegisterClass;
- if (LastRegArgValVT == MVT::f64)
- ArgRegEnd++;
-
- if (ArgRegEnd < Mips::A3) {
- // Both the last named formal argument and the first variable
- // argument are passed in registers.
- for (++ArgRegEnd; ArgRegEnd <= Mips::A3; ++ArgRegEnd) {
- unsigned Reg = AddLiveIn(DAG.getMachineFunction(), ArgRegEnd, RC);
- SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, MVT::i32);
-
- LastFI = MFI->CreateFixedObject(4, (ArgRegEnd-Mips::A0)*4, true);
- SDValue PtrOff = DAG.getFrameIndex(LastFI, getPointerTy());
- OutChains.push_back(DAG.getStore(Chain, dl, ArgValue, PtrOff,
- MachinePointerInfo(),
- false, false, 0));
-
- // Record the frame index of the first variable argument
- // which is a value necessary to VASTART.
- if (!MipsFI->getVarArgsFrameIndex())
- MipsFI->setVarArgsFrameIndex(LastFI);
- }
- } else {
- // Last named formal argument is in register Mips::A3, and the first
- // variable argument is on stack. Record the frame index of the first
- // variable argument.
- LastFI = MFI->CreateFixedObject(4, 16, true);
- MipsFI->setVarArgsFrameIndex(LastFI);
- }
- } else {
- // Last named formal argument and all the variable arguments are passed
- // on stack. Record the frame index of the first variable argument.
+ unsigned Idx = NextStackOffset / 4;
+ unsigned Reg = AddLiveIn(DAG.getMachineFunction(), O32IntRegs[Idx], RC);
+ SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, MVT::i32);
LastFI = MFI->CreateFixedObject(4, NextStackOffset, true);
- MipsFI->setVarArgsFrameIndex(LastFI);
+ SDValue PtrOff = DAG.getFrameIndex(LastFI, getPointerTy());
+ OutChains.push_back(DAG.getStore(Chain, dl, ArgValue, PtrOff,
+ MachinePointerInfo(),
+ false, false, 0));
}
}
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