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https://github.com/c64scene-ar/llvm-6502.git
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Added method to get Mips register numbers
Changed the stack frame layout, StackGrowsUp fits better to Mips strange stack. Stack offset calculation bug fixed! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41529 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bruno Cardoso Lopes
parent
a2b1bb5296
commit
51195af45f
@ -41,6 +41,48 @@ MipsRegisterInfo::MipsRegisterInfo(const TargetInstrInfo &tii)
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: MipsGenRegisterInfo(Mips::ADJCALLSTACKDOWN, Mips::ADJCALLSTACKUP),
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TII(tii) {}
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/// getRegisterNumbering - Given the enum value for some register, e.g.
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/// Mips::RA, return the number that it corresponds to (e.g. 31).
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unsigned MipsRegisterInfo::
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getRegisterNumbering(unsigned RegEnum)
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{
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switch (RegEnum) {
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case Mips::ZERO : return 0;
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case Mips::AT : return 1;
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case Mips::V0 : return 2;
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case Mips::V1 : return 3;
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case Mips::A0 : return 4;
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case Mips::A1 : return 5;
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case Mips::A2 : return 6;
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case Mips::A3 : return 7;
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case Mips::T0 : return 8;
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case Mips::T1 : return 9;
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case Mips::T2 : return 10;
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case Mips::T3 : return 11;
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case Mips::T4 : return 12;
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case Mips::T5 : return 13;
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case Mips::T6 : return 14;
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case Mips::T7 : return 15;
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case Mips::T8 : return 16;
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case Mips::T9 : return 17;
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case Mips::S0 : return 18;
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case Mips::S1 : return 19;
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case Mips::S2 : return 20;
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case Mips::S3 : return 21;
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case Mips::S4 : return 22;
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case Mips::S5 : return 23;
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case Mips::S6 : return 24;
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case Mips::S7 : return 25;
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case Mips::K0 : return 26;
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case Mips::K1 : return 27;
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case Mips::GP : return 28;
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case Mips::SP : return 29;
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case Mips::FP : return 30;
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case Mips::RA : return 31;
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default: assert(0 && "Unknown register number!");
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}
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}
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void MipsRegisterInfo::
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storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
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unsigned SrcReg, int FI,
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@ -114,6 +156,12 @@ foldMemoryOperand(MachineInstr* MI, unsigned OpNum, int FI) const
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return NewMI;
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}
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//===----------------------------------------------------------------------===//
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//
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// Callee Saved Registers methods
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//
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//===----------------------------------------------------------------------===//
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/// Mips Callee Saved Registers
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const unsigned* MipsRegisterInfo::
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getCalleeSavedRegs(const MachineFunction *MF) const
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@ -159,49 +207,50 @@ getReservedRegs(const MachineFunction &MF) const
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// Stack Frame Processing methods
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// +----------------------------+
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//
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// Too meet ABI, we construct the frame on the reverse
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// of natural order.
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// The stack is allocated decrementing the stack pointer on
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// the first instruction of a function prologue. Once decremented,
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// all stack referencesare are done thought a positive offset
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// from the stack/frame pointer, so the stack is considering
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// to grow up! Otherwise terrible hacks would have to be made
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// to get this stack ABI compliant :)
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//
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// The LLVM Frame will look like this:
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// The stack frame required by the ABI:
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// Offset
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//
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// As the stack grows down, we start at 0, and the reference
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// is decrement.
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// 0 ----------
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// 4 Args to pass
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// . saved $GP (used in PIC - not supported yet)
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// . Local Area
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// . saved "Callee Saved" Registers
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// . saved FP
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// . saved RA
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// StackSize -----------
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//
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// 0 ----------
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// -4 Args to pass
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// . saved "Callee Saved" Registers
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// . Local Area
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// . saved FP
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// . saved RA
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// -StackSize -----------
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//
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// On the EliminateFrameIndex we just negate the address above
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// and we get the stack frame required by the ABI, which is:
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//
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// sp + stacksize -------------
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// saved $RA (only on non-leaf functions)
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// saved $FP (only with frame pointer)
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// saved "Callee Saved" Registers
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// Local Area
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// saved $GP (used in PIC - not supported yet)
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// Args to pass area
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// sp -------------
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// Offset - offset from sp after stack allocation on function prologue
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//
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// The sp is the stack pointer subtracted/added from the stack size
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// at the Prologue/Epilogue
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//
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// References to the previous stack (to obtain arguments) are done
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// with fixed location stack frames using positive stack offsets.
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// with offsets that exceeds the stack size: (stacksize+(4*(num_arg-1))
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//
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// Examples:
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// - reference to the actual stack frame
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// for any local area var there is smt like : FI >= 0, StackOffset: -4
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// sw REGX, 4(REGY)
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// for any local area var there is smt like : FI >= 0, StackOffset: 4
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// sw REGX, 4(SP)
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//
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// - reference to previous stack frame
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// suppose there's a store to the 5th arguments : FI < 0, StackOffset: 16.
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// suppose there's a load to the 5th arguments : FI < 0, StackOffset: 16.
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// The emitted instruction will be something like:
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// sw REGX, 16+StackSize (REGY)
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// lw REGX, 16+StackSize(SP)
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//
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// Since the total stack size is unknown on LowerFORMAL_ARGUMENTS, all
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// stack references (ObjectOffset) created to reference the function
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// arguments, are negative numbers. This way, on eliminateFrameIndex it's
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// possible to detect those references and the offsets are adjusted to
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// their real location.
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//
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//
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//
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//===----------------------------------------------------------------------===//
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@ -252,7 +301,10 @@ eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
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DOUT << "stackSize : " << stackSize << "\n";
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#endif
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int Offset = ( (spOffset >= 0) ? (stackSize + spOffset) : (-spOffset));
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// as explained on LowerFORMAL_ARGUMENTS, detect negative offsets
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// and adjust SPOffsets considering the final stack size.
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int Offset = ((spOffset < 0) ? (stackSize + (-(spOffset+4))) : (spOffset));
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Offset += MI.getOperand(i-1).getImm();
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#ifndef NDEBUG
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DOUT << "Offset : " << Offset << "\n";
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@ -271,50 +323,51 @@ emitPrologue(MachineFunction &MF) const
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MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
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MachineBasicBlock::iterator MBBI = MBB.begin();
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// Replace the dummy '0' SPOffset by the negative offsets, as
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// explained on LowerFORMAL_ARGUMENTS
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MipsFI->adjustLoadArgsFI(MFI);
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MipsFI->adjustStoreVarArgsFI(MFI);
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// Get the number of bytes to allocate from the FrameInfo.
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int NumBytes = (int) MFI->getStackSize();
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#ifndef NDEBUG
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DOUT << "\n<--- EMIT PROLOGUE --->\n";
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DOUT << "Stack size :" << NumBytes << "\n";
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DOUT << "Actual Stack size :" << NumBytes << "\n";
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#endif
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// Don't need to allocate space on the stack.
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// No need to allocate space on the stack.
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if (NumBytes == 0) return;
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int FPOffset, RAOffset;
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// Always allocate space for saved RA and FP,
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// even if FramePointer is not used. When not
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// using FP, the last stack slot becomes empty
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// and RA is saved before it.
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// Allocate space for saved RA and FP when needed
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if ((hasFP(MF)) && (MFI->hasCalls())) {
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FPOffset = NumBytes+4;
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RAOffset = (NumBytes+8);
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FPOffset = NumBytes;
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RAOffset = (NumBytes+4);
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NumBytes += 8;
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} else if ((!hasFP(MF)) && (MFI->hasCalls())) {
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FPOffset = 0;
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RAOffset = NumBytes+4;
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RAOffset = NumBytes;
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NumBytes += 4;
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} else if ((hasFP(MF)) && (!MFI->hasCalls())) {
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FPOffset = NumBytes+4;
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FPOffset = NumBytes;
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RAOffset = 0;
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NumBytes += 4;
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}
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MFI->setObjectOffset(MFI->CreateStackObject(4,4), -FPOffset);
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MFI->setObjectOffset(MFI->CreateStackObject(4,4), -RAOffset);
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MFI->setObjectOffset(MFI->CreateStackObject(4,4), FPOffset);
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MFI->setObjectOffset(MFI->CreateStackObject(4,4), RAOffset);
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MipsFI->setFPStackOffset(FPOffset);
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MipsFI->setRAStackOffset(RAOffset);
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#ifndef NDEBUG
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DOUT << "FPOffset :" << FPOffset << "\n";
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DOUT << "RAOffset :" << RAOffset << "\n";
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#endif
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// Align stack.
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NumBytes += 12;
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unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
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NumBytes = ((NumBytes+Align-1)/Align*Align);
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#ifndef NDEBUG
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DOUT << "FPOffset :" << FPOffset << "\n";
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DOUT << "RAOffset :" << RAOffset << "\n";
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DOUT << "New stack size :" << NumBytes << "\n\n";
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#endif
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@ -359,13 +412,6 @@ emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const
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int FPOffset = MipsFI->getFPStackOffset();
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int RAOffset = MipsFI->getRAStackOffset();
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#ifndef NDEBUG
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DOUT << "\n<--- EMIT EPILOGUE --->" << "\n";
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DOUT << "Stack size :" << NumBytes << "\n";
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DOUT << "FPOffset :" << FPOffset << "\n";
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DOUT << "RAOffset :" << RAOffset << "\n\n";
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#endif
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// if framepointer enabled, restore it and restore the
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// stack pointer
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if (hasFP(MF)) {
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@ -27,6 +27,10 @@ struct MipsRegisterInfo : public MipsGenRegisterInfo {
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MipsRegisterInfo(const TargetInstrInfo &tii);
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/// getRegisterNumbering - Given the enum value for some register, e.g.
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/// Mips::RA, return the number that it corresponds to (e.g. 31).
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static unsigned getRegisterNumbering(unsigned RegEnum);
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/// Code Generation virtual methods...
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void storeRegToStackSlot(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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@ -62,6 +66,7 @@ struct MipsRegisterInfo : public MipsGenRegisterInfo {
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MachineBasicBlock &MBB,
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MachineBasicBlock::iterator I) const;
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/// Stack Frame Processing Methods
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void eliminateFrameIndex(MachineBasicBlock::iterator II,
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int SPAdj, RegScavenger *RS = NULL) const;
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@ -70,11 +75,11 @@ struct MipsRegisterInfo : public MipsGenRegisterInfo {
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void emitPrologue(MachineFunction &MF) const;
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void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const;
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// Debug information queries.
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/// Debug information queries.
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unsigned getRARegister() const;
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unsigned getFrameRegister(MachineFunction &MF) const;
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// Exception handling queries.
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/// Exception handling queries.
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unsigned getEHExceptionRegister() const;
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unsigned getEHHandlerRegister() const;
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};
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@ -31,13 +31,14 @@ createTargetAsmInfo() const
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}
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// DataLayout --> Big-endian, 32-bit pointer/ABI/alignment
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//
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// FrameInfo --> StackGrowsDown, 8 bytes aligned,
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// LOA : 0
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// The stack is always 8 byte aligned
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// On function prologue, the stack is created by decrementing
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// its pointer. Once decremented, all references are done with positive
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// offset from the stack/frame pointer, so StackGrowsUp is used.
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MipsTargetMachine::
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MipsTargetMachine(const Module &M, const std::string &FS):
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Subtarget(*this, M, FS), DataLayout("E-p:32:32:32"),
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InstrInfo(*this), FrameInfo(TargetFrameInfo::StackGrowsDown, 8, 0),
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InstrInfo(*this), FrameInfo(TargetFrameInfo::StackGrowsUp, 8, 0),
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TLInfo(*this) {}
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// return 0 and must specify -march to gen MIPS code.
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