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[AArch64] Refactor AArch64FrameLowering::emitPrologue. NFC.
http://reviews.llvm.org/D18125 Patch by Aditya Kumar. llvm-svn: 263461
This commit is contained in:
Chad Rosier
parent
cca4e6c42d
commit
41407e5c3d
@ -312,41 +312,41 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
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// All of the stack allocation is for locals.
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AFI->setLocalStackSize(NumBytes);
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// Label used to tie together the PROLOG_LABEL and the MachineMoves.
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MCSymbol *FrameLabel = MMI.getContext().createTempSymbol();
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if (!NumBytes)
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return;
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// REDZONE: If the stack size is less than 128 bytes, we don't need
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// to actually allocate.
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if (NumBytes && !canUseRedZone(MF)) {
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if (canUseRedZone(MF))
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++NumRedZoneFunctions;
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else {
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emitFrameOffset(MBB, MBBI, DL, AArch64::SP, AArch64::SP, -NumBytes, TII,
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MachineInstr::FrameSetup);
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// Label used to tie together the PROLOG_LABEL and the MachineMoves.
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MCSymbol *FrameLabel = MMI.getContext().createTempSymbol();
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// Encode the stack size of the leaf function.
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unsigned CFIIndex = MMI.addFrameInst(
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MCCFIInstruction::createDefCfaOffset(FrameLabel, -NumBytes));
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BuildMI(MBB, MBBI, DL, TII->get(TargetOpcode::CFI_INSTRUCTION))
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.addCFIIndex(CFIIndex)
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.setMIFlags(MachineInstr::FrameSetup);
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} else if (NumBytes) {
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++NumRedZoneFunctions;
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}
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return;
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}
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// Only set up FP if we actually need to.
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int FPOffset = 0;
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if (HasFP)
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// Frame pointer is fp = sp - 16.
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FPOffset = AFI->getCalleeSavedStackSize() - 16;
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NumBytes -= AFI->getCalleeSavedStackSize();
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assert(NumBytes >= 0 && "Negative stack allocation size!?");
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// All of the remaining stack allocations are for locals.
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AFI->setLocalStackSize(NumBytes);
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// Move past the saves of the callee-saved registers.
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MachineBasicBlock::iterator End = MBB.end();
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while (MBBI != End && MBBI->getFlag(MachineInstr::FrameSetup))
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++MBBI;
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NumBytes -= AFI->getCalleeSavedStackSize();
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assert(NumBytes >= 0 && "Negative stack allocation size!?");
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if (HasFP) {
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// Only set up FP if we actually need to. Frame pointer is fp = sp - 16.
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int FPOffset = AFI->getCalleeSavedStackSize() - 16;
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// Issue sub fp, sp, FPOffset or
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// mov fp,sp when FPOffset is zero.
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// Note: All stores of callee-saved registers are marked as "FrameSetup".
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@ -355,48 +355,46 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
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MachineInstr::FrameSetup);
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}
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// All of the remaining stack allocations are for locals.
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AFI->setLocalStackSize(NumBytes);
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// Allocate space for the rest of the frame.
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if (NumBytes) {
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const bool NeedsRealignment = RegInfo->needsStackRealignment(MF);
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unsigned scratchSPReg = AArch64::SP;
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const unsigned Alignment = MFI->getMaxAlignment();
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const bool NeedsRealignment = RegInfo->needsStackRealignment(MF);
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unsigned scratchSPReg = AArch64::SP;
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if (NumBytes && NeedsRealignment) {
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scratchSPReg = findScratchNonCalleeSaveRegister(&MBB);
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assert(scratchSPReg != AArch64::NoRegister);
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}
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if (NeedsRealignment) {
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scratchSPReg = findScratchNonCalleeSaveRegister(&MBB);
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assert(scratchSPReg != AArch64::NoRegister);
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}
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// If we're a leaf function, try using the red zone.
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if (NumBytes && !canUseRedZone(MF))
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// FIXME: in the case of dynamic re-alignment, NumBytes doesn't have
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// the correct value here, as NumBytes also includes padding bytes,
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// which shouldn't be counted here.
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emitFrameOffset(MBB, MBBI, DL, scratchSPReg, AArch64::SP, -NumBytes, TII,
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MachineInstr::FrameSetup);
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// If we're a leaf function, try using the red zone.
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if (!canUseRedZone(MF))
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// FIXME: in the case of dynamic re-alignment, NumBytes doesn't have
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// the correct value here, as NumBytes also includes padding bytes,
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// which shouldn't be counted here.
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emitFrameOffset(MBB, MBBI, DL, scratchSPReg, AArch64::SP, -NumBytes, TII,
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MachineInstr::FrameSetup);
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if (NumBytes && NeedsRealignment) {
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const unsigned NrBitsToZero = countTrailingZeros(Alignment);
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assert(NrBitsToZero > 1);
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assert(scratchSPReg != AArch64::SP);
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if (NeedsRealignment) {
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const unsigned Alignment = MFI->getMaxAlignment();
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const unsigned NrBitsToZero = countTrailingZeros(Alignment);
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assert(NrBitsToZero > 1);
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assert(scratchSPReg != AArch64::SP);
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// SUB X9, SP, NumBytes
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// -- X9 is temporary register, so shouldn't contain any live data here,
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// -- free to use. This is already produced by emitFrameOffset above.
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// AND SP, X9, 0b11111...0000
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// The logical immediates have a non-trivial encoding. The following
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// formula computes the encoded immediate with all ones but
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// NrBitsToZero zero bits as least significant bits.
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uint32_t andMaskEncoded =
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(1 <<12) // = N
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| ((64-NrBitsToZero) << 6) // immr
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| ((64-NrBitsToZero-1) << 0) // imms
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;
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BuildMI(MBB, MBBI, DL, TII->get(AArch64::ANDXri), AArch64::SP)
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.addReg(scratchSPReg, RegState::Kill)
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.addImm(andMaskEncoded);
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AFI->setStackRealigned(true);
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// SUB X9, SP, NumBytes
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// -- X9 is temporary register, so shouldn't contain any live data here,
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// -- free to use. This is already produced by emitFrameOffset above.
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// AND SP, X9, 0b11111...0000
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// The logical immediates have a non-trivial encoding. The following
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// formula computes the encoded immediate with all ones but
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// NrBitsToZero zero bits as least significant bits.
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uint32_t andMaskEncoded = (1 << 12) // = N
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| ((64 - NrBitsToZero) << 6) // immr
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| ((64 - NrBitsToZero - 1) << 0); // imms
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BuildMI(MBB, MBBI, DL, TII->get(AArch64::ANDXri), AArch64::SP)
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.addReg(scratchSPReg, RegState::Kill)
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.addImm(andMaskEncoded);
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AFI->setStackRealigned(true);
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}
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}
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// If we need a base pointer, set it up here. It's whatever the value of the
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@ -28,8 +28,8 @@
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; CHECK: .long 5
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; CHECK-NOT: .long _localgotequiv-(_table+20)
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; CHECK-NEXT: Ltmp1:
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; CHECK-NEXT: .long _localfoo@GOT-Ltmp1
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; CHECK-NEXT: Ltmp0:
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; CHECK-NEXT: .long _localfoo@GOT-Ltmp0
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%struct.data { i32 4, %struct.anon { i32 5,
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i32 trunc (i64 sub (i64 ptrtoint (i32** @localgotequiv to i64),
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i64 ptrtoint (i32* getelementptr inbounds ([4 x %struct.data], [4 x %struct.data]* @table, i32 0, i64 1, i32 1, i32 1) to i64))
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@ -38,8 +38,8 @@
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; CHECK: .long 5
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; CHECK-NOT: _extgotequiv-(_table+32)
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; CHECK-NEXT: Ltmp2:
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; CHECK-NEXT: _extfoo@GOT-Ltmp2
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; CHECK-NEXT: Ltmp1:
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; CHECK-NEXT: _extfoo@GOT-Ltmp1
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%struct.data { i32 4, %struct.anon { i32 5,
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i32 trunc (i64 sub (i64 ptrtoint (i32** @extgotequiv to i64),
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i64 ptrtoint (i32* getelementptr inbounds ([4 x %struct.data], [4 x %struct.data]* @table, i32 0, i64 2, i32 1, i32 1) to i64))
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@ -60,8 +60,8 @@
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; Test multiple uses of GOT equivalents.
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; CHECK-LABEL: _delta
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; CHECK: Ltmp3:
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; CHECK-NEXT: .long _extfoo@GOT-Ltmp3
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; CHECK: Ltmp2:
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; CHECK-NEXT: .long _extfoo@GOT-Ltmp2
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@delta = global i32 trunc (i64 sub (i64 ptrtoint (i32** @extgotequiv to i64),
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i64 ptrtoint (i32* @delta to i64))
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to i32)
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