mirror of
https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123399 91177308-0d34-0410-b5e6-96231b3b80d8
451 lines
16 KiB
C++
451 lines
16 KiB
C++
//=======- MBlazeFrameLowering.cpp - MBlaze 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 MBlaze implementation of TargetFrameLowering class.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "mblaze-frame-lowering"
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#include "MBlazeFrameLowering.h"
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#include "MBlazeInstrInfo.h"
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#include "MBlazeMachineFunction.h"
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#include "InstPrinter/MBlazeInstPrinter.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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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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namespace llvm {
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cl::opt<bool> DisableStackAdjust(
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"disable-mblaze-stack-adjust",
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cl::init(false),
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cl::desc("Disable MBlaze stack layout adjustment."),
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cl::Hidden);
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}
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static void replaceFrameIndexes(MachineFunction &MF,
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SmallVector<std::pair<int,int64_t>, 16> &FR) {
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MachineFrameInfo *MFI = MF.getFrameInfo();
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MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
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const SmallVector<std::pair<int,int64_t>, 16>::iterator FRB = FR.begin();
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const SmallVector<std::pair<int,int64_t>, 16>::iterator FRE = FR.end();
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SmallVector<std::pair<int,int64_t>, 16>::iterator FRI = FRB;
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for (; FRI != FRE; ++FRI) {
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MFI->RemoveStackObject(FRI->first);
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int NFI = MFI->CreateFixedObject(4, FRI->second, true);
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MBlazeFI->recordReplacement(FRI->first, NFI);
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for (MachineFunction::iterator MB=MF.begin(), ME=MF.end(); MB!=ME; ++MB) {
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MachineBasicBlock::iterator MBB = MB->begin();
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const MachineBasicBlock::iterator MBE = MB->end();
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for (; MBB != MBE; ++MBB) {
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MachineInstr::mop_iterator MIB = MBB->operands_begin();
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const MachineInstr::mop_iterator MIE = MBB->operands_end();
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for (MachineInstr::mop_iterator MII = MIB; MII != MIE; ++MII) {
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if (!MII->isFI() || MII->getIndex() != FRI->first) continue;
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DEBUG(dbgs() << "FOUND FI#" << MII->getIndex() << "\n");
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MII->setIndex(NFI);
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}
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}
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}
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}
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}
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//===----------------------------------------------------------------------===//
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//
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// Stack Frame Processing methods
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// +----------------------------+
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//
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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 references are are done through a positive offset
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// from the stack/frame pointer, so the stack is considered
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// to grow up.
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//
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//===----------------------------------------------------------------------===//
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static void analyzeFrameIndexes(MachineFunction &MF) {
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if (DisableStackAdjust) return;
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MachineFrameInfo *MFI = MF.getFrameInfo();
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MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
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const MachineRegisterInfo &MRI = MF.getRegInfo();
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MachineRegisterInfo::livein_iterator LII = MRI.livein_begin();
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MachineRegisterInfo::livein_iterator LIE = MRI.livein_end();
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const SmallVector<int, 16> &LiveInFI = MBlazeFI->getLiveIn();
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SmallVector<MachineInstr*, 16> EraseInstr;
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SmallVector<std::pair<int,int64_t>, 16> FrameRelocate;
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MachineBasicBlock *MBB = MF.getBlockNumbered(0);
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MachineBasicBlock::iterator MIB = MBB->begin();
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MachineBasicBlock::iterator MIE = MBB->end();
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int StackAdjust = 0;
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int StackOffset = -28;
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// In this loop we are searching frame indexes that corrospond to incoming
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// arguments that are already in the stack. We look for instruction sequences
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// like the following:
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//
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// LWI REG, FI1, 0
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// ...
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// SWI REG, FI2, 0
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//
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// As long as there are no defs of REG in the ... part, we can eliminate
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// the SWI instruction because the value has already been stored to the
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// stack by the caller. All we need to do is locate FI at the correct
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// stack location according to the calling convensions.
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//
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// Additionally, if the SWI operation kills the def of REG then we don't
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// need the LWI operation so we can erase it as well.
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for (unsigned i = 0, e = LiveInFI.size(); i < e; ++i) {
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for (MachineBasicBlock::iterator I=MIB; I != MIE; ++I) {
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if (I->getOpcode() != MBlaze::LWI || I->getNumOperands() != 3 ||
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!I->getOperand(1).isFI() || !I->getOperand(0).isReg() ||
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I->getOperand(1).getIndex() != LiveInFI[i]) continue;
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unsigned FIReg = I->getOperand(0).getReg();
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MachineBasicBlock::iterator SI = I;
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for (SI++; SI != MIE; ++SI) {
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if (!SI->getOperand(0).isReg() ||
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!SI->getOperand(1).isFI() ||
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SI->getOpcode() != MBlaze::SWI) continue;
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int FI = SI->getOperand(1).getIndex();
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if (SI->getOperand(0).getReg() != FIReg ||
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MFI->isFixedObjectIndex(FI) ||
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MFI->getObjectSize(FI) != 4) continue;
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if (SI->getOperand(0).isDef()) break;
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if (SI->getOperand(0).isKill()) {
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DEBUG(dbgs() << "LWI for FI#" << I->getOperand(1).getIndex()
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<< " removed\n");
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EraseInstr.push_back(I);
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}
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EraseInstr.push_back(SI);
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DEBUG(dbgs() << "SWI for FI#" << FI << " removed\n");
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FrameRelocate.push_back(std::make_pair(FI,StackOffset));
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DEBUG(dbgs() << "FI#" << FI << " relocated to " << StackOffset << "\n");
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StackOffset -= 4;
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StackAdjust += 4;
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break;
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}
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}
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}
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// In this loop we are searching for frame indexes that corrospond to
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// incoming arguments that are in registers. We look for instruction
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// sequences like the following:
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//
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// ... SWI REG, FI, 0
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//
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// As long as the ... part does not define REG and if REG is an incoming
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// parameter register then we know that, according to ABI convensions, the
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// caller has allocated stack space for it already. Instead of allocating
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// stack space on our frame, we record the correct location in the callers
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// frame.
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for (MachineRegisterInfo::livein_iterator LI = LII; LI != LIE; ++LI) {
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for (MachineBasicBlock::iterator I=MIB; I != MIE; ++I) {
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if (I->definesRegister(LI->first))
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break;
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if (I->getOpcode() != MBlaze::SWI || I->getNumOperands() != 3 ||
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!I->getOperand(1).isFI() || !I->getOperand(0).isReg() ||
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I->getOperand(1).getIndex() < 0) continue;
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if (I->getOperand(0).getReg() == LI->first) {
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int FI = I->getOperand(1).getIndex();
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MBlazeFI->recordLiveIn(FI);
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int FILoc = 0;
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switch (LI->first) {
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default: llvm_unreachable("invalid incoming parameter!");
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case MBlaze::R5: FILoc = -4; break;
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case MBlaze::R6: FILoc = -8; break;
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case MBlaze::R7: FILoc = -12; break;
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case MBlaze::R8: FILoc = -16; break;
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case MBlaze::R9: FILoc = -20; break;
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case MBlaze::R10: FILoc = -24; break;
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}
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StackAdjust += 4;
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FrameRelocate.push_back(std::make_pair(FI,FILoc));
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DEBUG(dbgs() << "FI#" << FI << " relocated to " << FILoc << "\n");
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break;
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}
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}
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}
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// Go ahead and erase all of the instructions that we determined were
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// no longer needed.
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for (int i = 0, e = EraseInstr.size(); i < e; ++i)
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MBB->erase(EraseInstr[i]);
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// Replace all of the frame indexes that we have relocated with new
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// fixed object frame indexes.
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replaceFrameIndexes(MF, FrameRelocate);
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}
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static void interruptFrameLayout(MachineFunction &MF) {
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const Function *F = MF.getFunction();
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llvm::CallingConv::ID CallConv = F->getCallingConv();
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// If this function is not using either the interrupt_handler
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// calling convention or the save_volatiles calling convention
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// then we don't need to do any additional frame layout.
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if (CallConv != llvm::CallingConv::MBLAZE_INTR &&
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CallConv != llvm::CallingConv::MBLAZE_SVOL)
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return;
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const MachineRegisterInfo &MRI = MF.getRegInfo();
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const MBlazeInstrInfo &TII =
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*static_cast<const MBlazeInstrInfo*>(MF.getTarget().getInstrInfo());
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// Determine if the calling convention is the interrupt_handler
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// calling convention. Some pieces of the prologue and epilogue
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// only need to be emitted if we are lowering and interrupt handler.
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bool isIntr = CallConv == llvm::CallingConv::MBLAZE_INTR;
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// Determine where to put prologue and epilogue additions
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MachineBasicBlock &MENT = MF.front();
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MachineBasicBlock &MEXT = MF.back();
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MachineBasicBlock::iterator MENTI = MENT.begin();
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MachineBasicBlock::iterator MEXTI = prior(MEXT.end());
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DebugLoc ENTDL = MENTI != MENT.end() ? MENTI->getDebugLoc() : DebugLoc();
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DebugLoc EXTDL = MEXTI != MEXT.end() ? MEXTI->getDebugLoc() : DebugLoc();
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// Store the frame indexes generated during prologue additions for use
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// when we are generating the epilogue additions.
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SmallVector<int, 10> VFI;
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// Build the prologue SWI for R3 - R12 if needed. Note that R11 must
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// always have a SWI because it is used when processing RMSR.
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for (unsigned r = MBlaze::R3; r <= MBlaze::R12; ++r) {
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if (!MRI.isPhysRegUsed(r) && !(isIntr && r == MBlaze::R11)) continue;
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int FI = MFI->CreateStackObject(4,4,false,false);
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VFI.push_back(FI);
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BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), r)
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.addFrameIndex(FI).addImm(0);
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}
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// Build the prologue SWI for R17, R18
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int R17FI = MFI->CreateStackObject(4,4,false,false);
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int R18FI = MFI->CreateStackObject(4,4,false,false);
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BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R17)
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.addFrameIndex(R17FI).addImm(0);
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BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R18)
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.addFrameIndex(R18FI).addImm(0);
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// Buid the prologue SWI and the epilogue LWI for RMSR if needed
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if (isIntr) {
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int MSRFI = MFI->CreateStackObject(4,4,false,false);
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BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::MFS), MBlaze::R11)
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.addReg(MBlaze::RMSR);
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BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R11)
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.addFrameIndex(MSRFI).addImm(0);
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BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R11)
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.addFrameIndex(MSRFI).addImm(0);
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BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::MTS), MBlaze::RMSR)
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.addReg(MBlaze::R11);
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}
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// Build the epilogue LWI for R17, R18
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BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R18)
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.addFrameIndex(R18FI).addImm(0);
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BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R17)
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.addFrameIndex(R17FI).addImm(0);
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// Build the epilogue LWI for R3 - R12 if needed
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for (unsigned r = MBlaze::R12, i = VFI.size(); r >= MBlaze::R3; --r) {
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if (!MRI.isPhysRegUsed(r)) continue;
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BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), r)
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.addFrameIndex(VFI[--i]).addImm(0);
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}
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}
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static void determineFrameLayout(MachineFunction &MF) {
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MachineFrameInfo *MFI = MF.getFrameInfo();
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MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
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// Replace the dummy '0' SPOffset by the negative offsets, as explained on
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// LowerFORMAL_ARGUMENTS. Leaving '0' for while is necessary to avoid
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// the approach done by calculateFrameObjectOffsets to the stack frame.
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MBlazeFI->adjustLoadArgsFI(MFI);
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MBlazeFI->adjustStoreVarArgsFI(MFI);
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// Get the number of bytes to allocate from the FrameInfo
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unsigned FrameSize = MFI->getStackSize();
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DEBUG(dbgs() << "Original Frame Size: " << FrameSize << "\n" );
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// Get the alignments provided by the target, and the maximum alignment
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// (if any) of the fixed frame objects.
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// unsigned MaxAlign = MFI->getMaxAlignment();
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unsigned TargetAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
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unsigned AlignMask = TargetAlign - 1;
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// Make sure the frame is aligned.
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FrameSize = (FrameSize + AlignMask) & ~AlignMask;
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MFI->setStackSize(FrameSize);
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DEBUG(dbgs() << "Aligned Frame Size: " << FrameSize << "\n" );
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}
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int MBlazeFrameLowering::getFrameIndexOffset(const MachineFunction &MF, int FI)
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const {
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const MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
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if (MBlazeFI->hasReplacement(FI))
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FI = MBlazeFI->getReplacement(FI);
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return TargetFrameLowering::getFrameIndexOffset(MF,FI);
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}
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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 MBlazeFrameLowering::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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void MBlazeFrameLowering::emitPrologue(MachineFunction &MF) const {
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MachineBasicBlock &MBB = MF.front();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const MBlazeInstrInfo &TII =
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*static_cast<const MBlazeInstrInfo*>(MF.getTarget().getInstrInfo());
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MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
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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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llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
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bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
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// Determine the correct frame layout
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determineFrameLayout(MF);
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// Get the number of bytes to allocate from the FrameInfo.
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unsigned StackSize = MFI->getStackSize();
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// No need to allocate space on the stack.
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if (StackSize == 0 && !MFI->adjustsStack() && !requiresRA) return;
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int FPOffset = MBlazeFI->getFPStackOffset();
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int RAOffset = MBlazeFI->getRAStackOffset();
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// Adjust stack : addi R1, R1, -imm
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BuildMI(MBB, MBBI, DL, TII.get(MBlaze::ADDIK), MBlaze::R1)
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.addReg(MBlaze::R1).addImm(-StackSize);
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// swi R15, R1, stack_loc
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if (MFI->adjustsStack() || requiresRA) {
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BuildMI(MBB, MBBI, DL, TII.get(MBlaze::SWI))
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.addReg(MBlaze::R15).addReg(MBlaze::R1).addImm(RAOffset);
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}
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if (hasFP(MF)) {
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// swi R19, R1, stack_loc
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BuildMI(MBB, MBBI, DL, TII.get(MBlaze::SWI))
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.addReg(MBlaze::R19).addReg(MBlaze::R1).addImm(FPOffset);
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// add R19, R1, R0
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BuildMI(MBB, MBBI, DL, TII.get(MBlaze::ADD), MBlaze::R19)
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.addReg(MBlaze::R1).addReg(MBlaze::R0);
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}
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}
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void MBlazeFrameLowering::emitEpilogue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
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const MBlazeInstrInfo &TII =
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*static_cast<const MBlazeInstrInfo*>(MF.getTarget().getInstrInfo());
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DebugLoc dl = MBBI->getDebugLoc();
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llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
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bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
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// Get the FI's where RA and FP are saved.
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int FPOffset = MBlazeFI->getFPStackOffset();
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int RAOffset = MBlazeFI->getRAStackOffset();
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if (hasFP(MF)) {
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// add R1, R19, R0
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BuildMI(MBB, MBBI, dl, TII.get(MBlaze::ADD), MBlaze::R1)
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.addReg(MBlaze::R19).addReg(MBlaze::R0);
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// lwi R19, R1, stack_loc
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BuildMI(MBB, MBBI, dl, TII.get(MBlaze::LWI), MBlaze::R19)
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.addReg(MBlaze::R1).addImm(FPOffset);
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}
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// lwi R15, R1, stack_loc
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if (MFI->adjustsStack() || requiresRA) {
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BuildMI(MBB, MBBI, dl, TII.get(MBlaze::LWI), MBlaze::R15)
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.addReg(MBlaze::R1).addImm(RAOffset);
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}
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// Get the number of bytes from FrameInfo
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int StackSize = (int) MFI->getStackSize();
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// addi R1, R1, imm
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if (StackSize) {
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BuildMI(MBB, MBBI, dl, TII.get(MBlaze::ADDIK), MBlaze::R1)
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.addReg(MBlaze::R1).addImm(StackSize);
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}
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}
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void MBlazeFrameLowering::
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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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MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
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llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
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|
bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
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|
|
|
if (MFI->adjustsStack() || requiresRA) {
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|
MBlazeFI->setRAStackOffset(0);
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|
MFI->CreateFixedObject(4,0,true);
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|
}
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|
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if (hasFP(MF)) {
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|
MBlazeFI->setFPStackOffset(4);
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|
MFI->CreateFixedObject(4,4,true);
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}
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|
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interruptFrameLayout(MF);
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|
analyzeFrameIndexes(MF);
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|
}
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