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https://github.com/c64scene-ar/llvm-6502.git
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94c5ae0875
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120229 91177308-0d34-0410-b5e6-96231b3b80d8
125 lines
4.4 KiB
C++
125 lines
4.4 KiB
C++
//====- BlackfinFrameInfo.cpp - Blackfin 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 Blackfin implementation of TargetFrameInfo class.
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//
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//===----------------------------------------------------------------------===//
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#include "BlackfinFrameInfo.h"
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#include "BlackfinInstrInfo.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/RegisterScavenging.h"
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#include "llvm/Target/TargetOptions.h"
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using namespace llvm;
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// hasFP - Return true if the specified function should have a dedicated frame
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// pointer register. This is true if the function has variable sized allocas or
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// if frame pointer elimination is disabled.
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bool BlackfinFrameInfo::hasFP(const MachineFunction &MF) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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return DisableFramePointerElim(MF) ||
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MFI->adjustsStack() || MFI->hasVarSizedObjects();
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}
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// Emit a prologue that sets up a stack frame.
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// On function entry, R0-R2 and P0 may hold arguments.
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// R3, P1, and P2 may be used as scratch registers
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void BlackfinFrameInfo::emitPrologue(MachineFunction &MF) const {
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MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
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MachineBasicBlock::iterator MBBI = MBB.begin();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const BlackfinRegisterInfo *RegInfo =
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static_cast<const BlackfinRegisterInfo*>(MF.getTarget().getRegisterInfo());
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const BlackfinInstrInfo &TII =
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*static_cast<const BlackfinInstrInfo*>(MF.getTarget().getInstrInfo());
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DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
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int FrameSize = MFI->getStackSize();
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if (FrameSize%4) {
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FrameSize = (FrameSize+3) & ~3;
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MFI->setStackSize(FrameSize);
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}
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if (!hasFP(MF)) {
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assert(!MFI->adjustsStack() &&
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"FP elimination on a non-leaf function is not supported");
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RegInfo->adjustRegister(MBB, MBBI, dl, BF::SP, BF::P1, -FrameSize);
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return;
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}
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// emit a LINK instruction
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if (FrameSize <= 0x3ffff) {
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BuildMI(MBB, MBBI, dl, TII.get(BF::LINK)).addImm(FrameSize);
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return;
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}
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// Frame is too big, do a manual LINK:
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// [--SP] = RETS;
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// [--SP] = FP;
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// FP = SP;
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// P1 = -FrameSize;
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// SP = SP + P1;
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BuildMI(MBB, MBBI, dl, TII.get(BF::PUSH))
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.addReg(BF::RETS, RegState::Kill);
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BuildMI(MBB, MBBI, dl, TII.get(BF::PUSH))
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.addReg(BF::FP, RegState::Kill);
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BuildMI(MBB, MBBI, dl, TII.get(BF::MOVE), BF::FP)
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.addReg(BF::SP);
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RegInfo->loadConstant(MBB, MBBI, dl, BF::P1, -FrameSize);
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BuildMI(MBB, MBBI, dl, TII.get(BF::ADDpp), BF::SP)
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.addReg(BF::SP, RegState::Kill)
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.addReg(BF::P1, RegState::Kill);
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}
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void BlackfinFrameInfo::emitEpilogue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const BlackfinRegisterInfo *RegInfo =
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static_cast<const BlackfinRegisterInfo*>(MF.getTarget().getRegisterInfo());
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const BlackfinInstrInfo &TII =
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*static_cast<const BlackfinInstrInfo*>(MF.getTarget().getInstrInfo());
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MachineBasicBlock::iterator MBBI = prior(MBB.end());
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DebugLoc dl = MBBI->getDebugLoc();
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int FrameSize = MFI->getStackSize();
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assert(FrameSize%4 == 0 && "Misaligned frame size");
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if (!hasFP(MF)) {
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assert(!MFI->adjustsStack() &&
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"FP elimination on a non-leaf function is not supported");
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RegInfo->adjustRegister(MBB, MBBI, dl, BF::SP, BF::P1, FrameSize);
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return;
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}
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// emit an UNLINK instruction
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BuildMI(MBB, MBBI, dl, TII.get(BF::UNLINK));
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}
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void BlackfinFrameInfo::
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processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
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RegScavenger *RS) const {
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const BlackfinRegisterInfo *RegInfo =
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static_cast<const BlackfinRegisterInfo*>(MF.getTarget().getRegisterInfo());
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const TargetRegisterClass *RC = BF::DPRegisterClass;
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if (RegInfo->requiresRegisterScavenging(MF)) {
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// Reserve a slot close to SP or frame pointer.
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RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
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RC->getAlignment(),
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false));
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}
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}
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