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https://github.com/c64scene-ar/llvm-6502.git
synced 2025-06-21 18:24:23 +00:00
Rename TargetFrameInfo into TargetFrameLowering. Also, put couple of FIXMEs and fixes here and there.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123170 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov
386
lib/Target/SystemZ/SystemZFrameLowering.cpp
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386
lib/Target/SystemZ/SystemZFrameLowering.cpp
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//=====- SystemZFrameLowering.cpp - SystemZ Frame Information ------*- C++ -*-====//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the SystemZ implementation of TargetFrameLowering class.
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//
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//===----------------------------------------------------------------------===//
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#include "SystemZFrameLowering.h"
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#include "SystemZInstrBuilder.h"
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#include "SystemZInstrInfo.h"
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#include "SystemZMachineFunctionInfo.h"
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#include "llvm/Function.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/CommandLine.h"
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using namespace llvm;
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SystemZFrameLowering::SystemZFrameLowering(const SystemZSubtarget &sti)
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: TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 8, -160), STI(sti) {
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// Fill the spill offsets map
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static const unsigned SpillOffsTab[][2] = {
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{ SystemZ::R2D, 0x10 },
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{ SystemZ::R3D, 0x18 },
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{ SystemZ::R4D, 0x20 },
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{ SystemZ::R5D, 0x28 },
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{ SystemZ::R6D, 0x30 },
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{ SystemZ::R7D, 0x38 },
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{ SystemZ::R8D, 0x40 },
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{ SystemZ::R9D, 0x48 },
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{ SystemZ::R10D, 0x50 },
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{ SystemZ::R11D, 0x58 },
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{ SystemZ::R12D, 0x60 },
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{ SystemZ::R13D, 0x68 },
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{ SystemZ::R14D, 0x70 },
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{ SystemZ::R15D, 0x78 }
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};
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RegSpillOffsets.grow(SystemZ::NUM_TARGET_REGS);
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for (unsigned i = 0, e = array_lengthof(SpillOffsTab); i != e; ++i)
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RegSpillOffsets[SpillOffsTab[i][0]] = SpillOffsTab[i][1];
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}
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/// needsFP - Return true if the specified function should have a dedicated
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/// frame pointer register. This is true if the function has variable sized
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/// allocas or if frame pointer elimination is disabled.
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bool SystemZFrameLowering::hasFP(const MachineFunction &MF) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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return DisableFramePointerElim(MF) || MFI->hasVarSizedObjects();
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}
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/// emitSPUpdate - Emit a series of instructions to increment / decrement the
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/// stack pointer by a constant value.
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static
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void emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
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int64_t NumBytes, const TargetInstrInfo &TII) {
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unsigned Opc; uint64_t Chunk;
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bool isSub = NumBytes < 0;
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uint64_t Offset = isSub ? -NumBytes : NumBytes;
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if (Offset >= (1LL << 15) - 1) {
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Opc = SystemZ::ADD64ri32;
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Chunk = (1LL << 31) - 1;
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} else {
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Opc = SystemZ::ADD64ri16;
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Chunk = (1LL << 15) - 1;
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}
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DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
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while (Offset) {
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uint64_t ThisVal = (Offset > Chunk) ? Chunk : Offset;
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MachineInstr *MI =
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BuildMI(MBB, MBBI, DL, TII.get(Opc), SystemZ::R15D)
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.addReg(SystemZ::R15D).addImm(isSub ? -ThisVal : ThisVal);
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// The PSW implicit def is dead.
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MI->getOperand(3).setIsDead();
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Offset -= ThisVal;
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}
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}
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void SystemZFrameLowering::emitPrologue(MachineFunction &MF) const {
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MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const SystemZInstrInfo &TII =
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*static_cast<const SystemZInstrInfo*>(MF.getTarget().getInstrInfo());
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SystemZMachineFunctionInfo *SystemZMFI =
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MF.getInfo<SystemZMachineFunctionInfo>();
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MachineBasicBlock::iterator MBBI = MBB.begin();
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DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
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// Get the number of bytes to allocate from the FrameInfo.
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// Note that area for callee-saved stuff is already allocated, thus we need to
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// 'undo' the stack movement.
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uint64_t StackSize = MFI->getStackSize();
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StackSize -= SystemZMFI->getCalleeSavedFrameSize();
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uint64_t NumBytes = StackSize - getOffsetOfLocalArea();
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// Skip the callee-saved push instructions.
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while (MBBI != MBB.end() &&
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(MBBI->getOpcode() == SystemZ::MOV64mr ||
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MBBI->getOpcode() == SystemZ::MOV64mrm))
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++MBBI;
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if (MBBI != MBB.end())
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DL = MBBI->getDebugLoc();
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// adjust stack pointer: R15 -= numbytes
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if (StackSize || MFI->hasCalls()) {
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assert(MF.getRegInfo().isPhysRegUsed(SystemZ::R15D) &&
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"Invalid stack frame calculation!");
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emitSPUpdate(MBB, MBBI, -(int64_t)NumBytes, TII);
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}
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if (hasFP(MF)) {
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// Update R11 with the new base value...
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BuildMI(MBB, MBBI, DL, TII.get(SystemZ::MOV64rr), SystemZ::R11D)
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.addReg(SystemZ::R15D);
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// Mark the FramePtr as live-in in every block except the entry.
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for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
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I != E; ++I)
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I->addLiveIn(SystemZ::R11D);
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}
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}
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void SystemZFrameLowering::emitEpilogue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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MachineBasicBlock::iterator MBBI = prior(MBB.end());
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const SystemZInstrInfo &TII =
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*static_cast<const SystemZInstrInfo*>(MF.getTarget().getInstrInfo());
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SystemZMachineFunctionInfo *SystemZMFI =
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MF.getInfo<SystemZMachineFunctionInfo>();
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unsigned RetOpcode = MBBI->getOpcode();
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switch (RetOpcode) {
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case SystemZ::RET: break; // These are ok
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default:
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assert(0 && "Can only insert epilog into returning blocks");
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}
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// Get the number of bytes to allocate from the FrameInfo
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// Note that area for callee-saved stuff is already allocated, thus we need to
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// 'undo' the stack movement.
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uint64_t StackSize =
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MFI->getStackSize() - SystemZMFI->getCalleeSavedFrameSize();
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uint64_t NumBytes = StackSize - getOffsetOfLocalArea();
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// Skip the final terminator instruction.
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while (MBBI != MBB.begin()) {
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MachineBasicBlock::iterator PI = prior(MBBI);
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--MBBI;
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if (!PI->getDesc().isTerminator())
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break;
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}
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// During callee-saved restores emission stack frame was not yet finialized
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// (and thus - the stack size was unknown). Tune the offset having full stack
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// size in hands.
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if (StackSize || MFI->hasCalls()) {
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assert((MBBI->getOpcode() == SystemZ::MOV64rmm ||
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MBBI->getOpcode() == SystemZ::MOV64rm) &&
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"Expected to see callee-save register restore code");
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assert(MF.getRegInfo().isPhysRegUsed(SystemZ::R15D) &&
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"Invalid stack frame calculation!");
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unsigned i = 0;
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MachineInstr &MI = *MBBI;
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while (!MI.getOperand(i).isImm()) {
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++i;
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assert(i < MI.getNumOperands() && "Unexpected restore code!");
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}
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uint64_t Offset = NumBytes + MI.getOperand(i).getImm();
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// If Offset does not fit into 20-bit signed displacement field we need to
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// emit some additional code...
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if (Offset > 524287) {
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// Fold the displacement into load instruction as much as possible.
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NumBytes = Offset - 524287;
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Offset = 524287;
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emitSPUpdate(MBB, MBBI, NumBytes, TII);
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}
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MI.getOperand(i).ChangeToImmediate(Offset);
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}
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}
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int SystemZFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
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int FI) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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const SystemZMachineFunctionInfo *SystemZMFI =
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MF.getInfo<SystemZMachineFunctionInfo>();
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int Offset = MFI->getObjectOffset(FI) + MFI->getOffsetAdjustment();
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uint64_t StackSize = MFI->getStackSize();
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// Fixed objects are really located in the "previous" frame.
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if (FI < 0)
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StackSize -= SystemZMFI->getCalleeSavedFrameSize();
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Offset += StackSize - getOffsetOfLocalArea();
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// Skip the register save area if we generated the stack frame.
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if (StackSize || MFI->hasCalls())
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Offset -= getOffsetOfLocalArea();
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return Offset;
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}
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bool
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SystemZFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MI,
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const std::vector<CalleeSavedInfo> &CSI,
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const TargetRegisterInfo *TRI) const {
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if (CSI.empty())
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return false;
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DebugLoc DL;
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if (MI != MBB.end()) DL = MI->getDebugLoc();
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MachineFunction &MF = *MBB.getParent();
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const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
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SystemZMachineFunctionInfo *MFI = MF.getInfo<SystemZMachineFunctionInfo>();
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unsigned CalleeFrameSize = 0;
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// Scan the callee-saved and find the bounds of register spill area.
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unsigned LowReg = 0, HighReg = 0, StartOffset = -1U, EndOffset = 0;
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for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
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unsigned Reg = CSI[i].getReg();
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if (!SystemZ::FP64RegClass.contains(Reg)) {
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unsigned Offset = RegSpillOffsets[Reg];
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CalleeFrameSize += 8;
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if (StartOffset > Offset) {
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LowReg = Reg; StartOffset = Offset;
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}
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if (EndOffset < Offset) {
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HighReg = Reg; EndOffset = RegSpillOffsets[Reg];
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}
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}
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}
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// Save information for epilogue inserter.
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MFI->setCalleeSavedFrameSize(CalleeFrameSize);
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MFI->setLowReg(LowReg); MFI->setHighReg(HighReg);
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// Save GPRs
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if (StartOffset) {
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// Build a store instruction. Use STORE MULTIPLE instruction if there are many
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// registers to store, otherwise - just STORE.
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MachineInstrBuilder MIB =
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BuildMI(MBB, MI, DL, TII.get((LowReg == HighReg ?
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SystemZ::MOV64mr : SystemZ::MOV64mrm)));
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// Add store operands.
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MIB.addReg(SystemZ::R15D).addImm(StartOffset);
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if (LowReg == HighReg)
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MIB.addReg(0);
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MIB.addReg(LowReg, RegState::Kill);
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if (LowReg != HighReg)
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MIB.addReg(HighReg, RegState::Kill);
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// Do a second scan adding regs as being killed by instruction
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for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
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unsigned Reg = CSI[i].getReg();
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// Add the callee-saved register as live-in. It's killed at the spill.
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MBB.addLiveIn(Reg);
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if (Reg != LowReg && Reg != HighReg)
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MIB.addReg(Reg, RegState::ImplicitKill);
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}
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}
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// Save FPRs
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for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
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unsigned Reg = CSI[i].getReg();
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if (SystemZ::FP64RegClass.contains(Reg)) {
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MBB.addLiveIn(Reg);
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TII.storeRegToStackSlot(MBB, MI, Reg, true, CSI[i].getFrameIdx(),
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&SystemZ::FP64RegClass, TRI);
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}
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}
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return true;
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}
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bool
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SystemZFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MI,
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const std::vector<CalleeSavedInfo> &CSI,
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const TargetRegisterInfo *TRI) const {
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if (CSI.empty())
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return false;
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DebugLoc DL;
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if (MI != MBB.end()) DL = MI->getDebugLoc();
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MachineFunction &MF = *MBB.getParent();
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const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
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SystemZMachineFunctionInfo *MFI = MF.getInfo<SystemZMachineFunctionInfo>();
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// Restore FP registers
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for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
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unsigned Reg = CSI[i].getReg();
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if (SystemZ::FP64RegClass.contains(Reg))
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TII.loadRegFromStackSlot(MBB, MI, Reg, CSI[i].getFrameIdx(),
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&SystemZ::FP64RegClass, TRI);
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}
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// Restore GP registers
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unsigned LowReg = MFI->getLowReg(), HighReg = MFI->getHighReg();
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unsigned StartOffset = RegSpillOffsets[LowReg];
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if (StartOffset) {
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// Build a load instruction. Use LOAD MULTIPLE instruction if there are many
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// registers to load, otherwise - just LOAD.
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MachineInstrBuilder MIB =
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BuildMI(MBB, MI, DL, TII.get((LowReg == HighReg ?
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SystemZ::MOV64rm : SystemZ::MOV64rmm)));
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// Add store operands.
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MIB.addReg(LowReg, RegState::Define);
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if (LowReg != HighReg)
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MIB.addReg(HighReg, RegState::Define);
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MIB.addReg(hasFP(MF) ? SystemZ::R11D : SystemZ::R15D);
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MIB.addImm(StartOffset);
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if (LowReg == HighReg)
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MIB.addReg(0);
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// Do a second scan adding regs as being defined by instruction
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for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
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unsigned Reg = CSI[i].getReg();
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if (Reg != LowReg && Reg != HighReg)
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MIB.addReg(Reg, RegState::ImplicitDefine);
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}
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}
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return true;
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}
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void
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SystemZFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
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RegScavenger *RS) const {
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// Determine whether R15/R14 will ever be clobbered inside the function. And
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// if yes - mark it as 'callee' saved.
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MachineFrameInfo *FFI = MF.getFrameInfo();
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MachineRegisterInfo &MRI = MF.getRegInfo();
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// Check whether high FPRs are ever used, if yes - we need to save R15 as
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// well.
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static const unsigned HighFPRs[] = {
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SystemZ::F8L, SystemZ::F9L, SystemZ::F10L, SystemZ::F11L,
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SystemZ::F12L, SystemZ::F13L, SystemZ::F14L, SystemZ::F15L,
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SystemZ::F8S, SystemZ::F9S, SystemZ::F10S, SystemZ::F11S,
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SystemZ::F12S, SystemZ::F13S, SystemZ::F14S, SystemZ::F15S,
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};
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bool HighFPRsUsed = false;
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for (unsigned i = 0, e = array_lengthof(HighFPRs); i != e; ++i)
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HighFPRsUsed |= MRI.isPhysRegUsed(HighFPRs[i]);
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if (FFI->hasCalls())
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/* FIXME: function is varargs */
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/* FIXME: function grabs RA */
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/* FIXME: function calls eh_return */
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MRI.setPhysRegUsed(SystemZ::R14D);
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if (HighFPRsUsed ||
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FFI->hasCalls() ||
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FFI->getObjectIndexEnd() != 0 || // Contains automatic variables
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FFI->hasVarSizedObjects() // Function calls dynamic alloca's
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/* FIXME: function is varargs */)
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MRI.setPhysRegUsed(SystemZ::R15D);
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}
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