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Fix stack layout error in MBlaze backend.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122631 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Wesley Peck 2010-12-29 19:46:28 +00:00
parent b2624eda5a
commit b4aec92453
2 changed files with 98 additions and 37 deletions
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114
lib/Target/MBlaze/MBlazeFrameInfo.cpp
View File

@ -11,6 +11,8 @@
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mblaze-frame-info"
#include "MBlazeFrameInfo.h"
#include "MBlazeInstrInfo.h"
#include "MBlazeMachineFunction.h"
@ -24,6 +26,9 @@
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
@ -66,6 +71,23 @@ static void analyzeFrameIndexes(MachineFunction &MF) {
int StackAdjust = 0;
int StackOffset = -28;
// In this loop we are searching frame indexes that corrospond to incoming
// arguments that are already in the stack. We look for instruction sequences
// like the following:
//
// LWI REG, FI1, 0
// ...
// SWI REG, FI2, 0
//
// As long as there are no defs of REG in the ... part, we can eliminate
// the SWI instruction because the value has already been stored to the
// stack by the caller. All we need to do is locate FI at the correct
// stack location according to the calling convensions.
//
// Additionally, if the SWI operation kills the def of REG then we don't
// need the LWI operation so we can erase it as well.
#if 1
for (unsigned i = 0, e = LiveInFI.size(); i < e; ++i) {
for (MachineBasicBlock::iterator I=MIB; I != MIE; ++I) {
if (I->getOpcode() != MBlaze::LWI || I->getNumOperands() != 3 ||
@ -75,60 +97,88 @@ static void analyzeFrameIndexes(MachineFunction &MF) {
unsigned FIReg = I->getOperand(0).getReg();
MachineBasicBlock::iterator SI = I;
for (SI++; SI != MIE; ++SI) {
if (!SI->getOperand(0).isReg()) continue;
if (!SI->getOperand(1).isFI()) continue;
if (SI->getOpcode() != MBlaze::SWI) continue;
if (!SI->getOperand(0).isReg() ||
!SI->getOperand(1).isFI() ||
SI->getOpcode() != MBlaze::SWI) continue;
int FI = SI->getOperand(1).getIndex();
if (SI->getOperand(0).getReg() != FIReg) continue;
if (MFI->isFixedObjectIndex(FI)) continue;
if (MFI->getObjectSize(FI) != 4) continue;
if (SI->getOperand(0).getReg() != FIReg ||
MFI->isFixedObjectIndex(FI) ||
MFI->getObjectSize(FI) != 4) continue;
if (SI->getOperand(0).isDef()) break;
if (SI->getOperand(0).isKill())
if (SI->getOperand(0).isKill()) {
DEBUG(dbgs() << "LWI for FI#" << I->getOperand(1).getIndex()
<< " removed\n");
EraseInstr.push_back(I);
}
EraseInstr.push_back(SI);
DEBUG(dbgs() << "SWI for FI#" << FI << " removed\n");
MBlazeFI->recordLoadArgsFI(FI, StackOffset);
DEBUG(dbgs() << "FI#" << FI << " relocated to " << StackOffset << "\n");
StackOffset -= 4;
StackAdjust += 4;
break;
}
}
}
#endif
for (MachineBasicBlock::iterator I=MBB->begin(), E=MBB->end(); I != E; ++I) {
if (I->getOpcode() != MBlaze::SWI || I->getNumOperands() != 3 ||
!I->getOperand(1).isFI() || !I->getOperand(0).isReg() ||
I->getOperand(1).getIndex() < 0) continue;
// In this loop we are searching for frame indexes that corrospond to
// incoming arguments that are in registers. We look for instruction
// sequences like the following:
//
// ... SWI REG, FI, 0
//
// As long as the ... part does not define REG and if REG is an incoming
// parameter register then we know that, according to ABI convensions, the
// caller has allocated stack space for it already. Instead of allocating
// stack space on our frame, we record the correct location in the callers
// frame.
#if 1
for (MachineRegisterInfo::livein_iterator LI = LII; LI != LIE; ++LI) {
for (MachineBasicBlock::iterator I=MIB; I != MIE; ++I) {
if (I->definesRegister(LI->first))
break;
if (I->getOpcode() != MBlaze::SWI || I->getNumOperands() != 3 ||
!I->getOperand(1).isFI() || !I->getOperand(0).isReg() ||
I->getOperand(1).getIndex() < 0) continue;
unsigned FIReg = 0;
for (MachineRegisterInfo::livein_iterator LI = LII; LI != LIE; ++LI) {
if (I->getOperand(0).getReg() == LI->first) {
FIReg = LI->first;
int FI = I->getOperand(1).getIndex();
MBlazeFI->recordLiveIn(FI);
int FILoc = 0;
switch (LI->first) {
default: llvm_unreachable("invalid incoming parameter!");
case MBlaze::R5: FILoc = -4; break;
case MBlaze::R6: FILoc = -8; break;
case MBlaze::R7: FILoc = -12; break;
case MBlaze::R8: FILoc = -16; break;
case MBlaze::R9: FILoc = -20; break;
case MBlaze::R10: FILoc = -24; break;
}
StackAdjust += 4;
MBlazeFI->recordLoadArgsFI(FI, FILoc);
DEBUG(dbgs() << "FI#" << FI << " relocated to " << FILoc << "\n");
break;
}
}
if (FIReg) {
int FI = I->getOperand(1).getIndex();
MBlazeFI->recordLiveIn(FI);
StackAdjust += 4;
switch (FIReg) {
default: llvm_unreachable("invalid incoming parameter!");
case MBlaze::R5: MBlazeFI->recordLoadArgsFI(FI, -4); break;
case MBlaze::R6: MBlazeFI->recordLoadArgsFI(FI, -8); break;
case MBlaze::R7: MBlazeFI->recordLoadArgsFI(FI, -12); break;
case MBlaze::R8: MBlazeFI->recordLoadArgsFI(FI, -16); break;
case MBlaze::R9: MBlazeFI->recordLoadArgsFI(FI, -20); break;
case MBlaze::R10: MBlazeFI->recordLoadArgsFI(FI, -24); break;
}
}
}
#endif
// Go ahead and erase all of the instructions that we determined were
// no longer needed.
for (int i = 0, e = EraseInstr.size(); i < e; ++i)
MBB->erase(EraseInstr[i]);
DEBUG(dbgs() << "Final stack adjustment: " << StackAdjust << "\n");
MBlazeFI->setStackAdjust(StackAdjust);
}
@ -230,7 +280,10 @@ static void determineFrameLayout(MachineFunction &MF) {
// Get the number of bytes to allocate from the FrameInfo
unsigned FrameSize = MFI->getStackSize();
DEBUG(dbgs() << "Original Frame Size: " << FrameSize << "\n" );
FrameSize -= MBlazeFI->getStackAdjust();
DEBUG(dbgs() << "Adjusted Frame Size: " << FrameSize << "\n" );
// Get the alignments provided by the target, and the maximum alignment
// (if any) of the fixed frame objects.
@ -241,6 +294,7 @@ static void determineFrameLayout(MachineFunction &MF) {
// Make sure the frame is aligned.
FrameSize = (FrameSize + AlignMask) & ~AlignMask;
MFI->setStackSize(FrameSize);
DEBUG(dbgs() << "Aligned Frame Size: " << FrameSize << "\n" );
}
// hasFP - Return true if the specified function should have a dedicated frame

21
lib/Target/MBlaze/MBlazeRegisterInfo.cpp
View File

@ -12,7 +12,7 @@
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mblaze-reg-info"
#define DEBUG_TYPE "mblaze-frame-info"
#include "MBlaze.h"
#include "MBlazeSubtarget.h"
@ -277,25 +277,32 @@ eliminateFrameIndex(MachineBasicBlock::iterator II, int SPAdj,
unsigned oi = i == 2 ? 1 : 2;
DEBUG(errs() << "\nFunction : " << MF.getFunction()->getName() << "\n";
errs() << "<--------->\n" << MI);
DEBUG(dbgs() << "\nFunction : " << MF.getFunction()->getName() << "\n";
dbgs() << "<--------->\n" << MI);
int FrameIndex = MI.getOperand(i).getIndex();
int stackSize = MF.getFrameInfo()->getStackSize();
int spOffset = MF.getFrameInfo()->getObjectOffset(FrameIndex);
DEBUG(errs() << "FrameIndex : " << FrameIndex << "\n"
DEBUG(dbgs() << "FrameIndex : " << FrameIndex << "\n"
<< "spOffset : " << spOffset << "\n"
<< "stackSize : " << stackSize << "\n");
<< "stackSize : " << stackSize << "\n"
<< "isFixed : " << MFI->isFixedObjectIndex(FrameIndex) << "\n"
<< "isLiveIn : " << MBlazeFI->isLiveIn(FrameIndex) << "\n"
<< "isSpill : " << MFI->isSpillSlotObjectIndex(FrameIndex)
<< "\n" );
// as explained on LowerFormalArguments, detect negative offsets
// and adjust SPOffsets considering the final stack size.
int Offset = (spOffset < 0) ? (stackSize - spOffset) : spOffset;
Offset += MI.getOperand(oi).getImm();
if (!MFI->isFixedObjectIndex(FrameIndex) && !MBlazeFI->isLiveIn(FrameIndex) && spOffset >= 0)
if (!MFI->isFixedObjectIndex(FrameIndex) &&
!MFI->isSpillSlotObjectIndex(FrameIndex) &&
!MBlazeFI->isLiveIn(FrameIndex) &&
spOffset >= 0)
Offset -= MBlazeFI->getStackAdjust();
DEBUG(errs() << "Offset : " << Offset << "\n" << "<--------->\n");
DEBUG(dbgs() << "Offset : " << Offset << "\n" << "<--------->\n");
MI.getOperand(oi).ChangeToImmediate(Offset);
MI.getOperand(i).ChangeToRegister(getFrameRegister(MF), false);