Make $fp and $ra callee-saved registers and let PrologEpilogInserter handle
saving and restoring them.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131745 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsFrameLowering.cpp b/lib/Target/Mips/MipsFrameLowering.cpp
index 21e3314..819feed 100644
--- a/lib/Target/Mips/MipsFrameLowering.cpp
+++ b/lib/Target/Mips/MipsFrameLowering.cpp
@@ -156,26 +156,6 @@
StackOffset += MFI->getObjectAlignment(CSI[i].getFrameIdx());
}
- // Stack locations for FP and RA. If only one of them is used,
- // the space must be allocated for both, otherwise no space at all.
- if (hasFP(MF) || MFI->adjustsStack()) {
- // FP stack location
- MFI->setObjectOffset(MFI->CreateStackObject(RegSize, RegSize, true),
- StackOffset);
- MipsFI->setFPStackOffset(StackOffset);
- TopCPUSavedRegOff = StackOffset;
- StackOffset += RegSize;
-
- // SP stack location
- MFI->setObjectOffset(MFI->CreateStackObject(RegSize, RegSize, true),
- StackOffset);
- MipsFI->setRAStackOffset(StackOffset);
- StackOffset += RegSize;
-
- if (MFI->adjustsStack())
- TopCPUSavedRegOff += RegSize;
- }
-
StackOffset = ((StackOffset+StackAlign-1)/StackAlign*StackAlign);
// Adjust FPU Callee Saved Registers Area. This Area must be
@@ -267,9 +247,6 @@
// No need to allocate space on the stack.
if (StackSize == 0 && !MFI->adjustsStack()) return;
- int FPOffset = MipsFI->getFPStackOffset();
- int RAOffset = MipsFI->getRAStackOffset();
-
BuildMI(MBB, MBBI, dl, TII.get(Mips::NOREORDER));
// TODO: check need from GP here.
@@ -288,36 +265,11 @@
if (ATUsed)
BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
- // Save the return address only if the function isn't a leaf one.
- // sw $ra, stack_loc($sp)
- if (MFI->adjustsStack()) {
- ATUsed = expandRegLargeImmPair(Mips::SP, RAOffset, NewReg, NewImm, MBB,
- MBBI);
- BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
- .addReg(Mips::RA).addImm(NewImm).addReg(NewReg);
-
- // FIXME: change this when mips goes MC".
- if (ATUsed)
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
- }
-
- // if framepointer enabled, save it and set it
- // to point to the stack pointer
- if (hasFP(MF)) {
- // sw $fp,stack_loc($sp)
- ATUsed = expandRegLargeImmPair(Mips::SP, FPOffset, NewReg, NewImm, MBB,
- MBBI);
- BuildMI(MBB, MBBI, dl, TII.get(Mips::SW))
- .addReg(Mips::FP).addImm(NewImm).addReg(NewReg);
-
- // FIXME: change this when mips goes MC".
- if (ATUsed)
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
-
+ // if framepointer enabled, set it to point to the stack pointer.
+ if (hasFP(MF))
// move $fp, $sp
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::FP)
.addReg(Mips::SP).addReg(Mips::ZERO);
- }
// Restore GP from the saved stack location
if (MipsFI->needGPSaveRestore())
@@ -329,7 +281,6 @@
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
MachineFrameInfo *MFI = MF.getFrameInfo();
- MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
const MipsInstrInfo &TII =
*static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
DebugLoc dl = MBBI->getDebugLoc();
@@ -337,45 +288,16 @@
// Get the number of bytes from FrameInfo
int NumBytes = (int) MFI->getStackSize();
- // Get the FI's where RA and FP are saved.
- int FPOffset = MipsFI->getFPStackOffset();
- int RAOffset = MipsFI->getRAStackOffset();
-
unsigned NewReg = 0;
int NewImm = 0;
bool ATUsed = false;
- // if framepointer enabled, restore it and restore the
- // stack pointer
- if (hasFP(MF)) {
+ // if framepointer enabled, restore the stack pointer.
+ if (hasFP(MF))
// move $sp, $fp
BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::SP)
.addReg(Mips::FP).addReg(Mips::ZERO);
- // lw $fp,stack_loc($sp)
- ATUsed = expandRegLargeImmPair(Mips::SP, FPOffset, NewReg, NewImm, MBB,
- MBBI);
- BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::FP)
- .addImm(NewImm).addReg(NewReg);
-
- // FIXME: change this when mips goes MC".
- if (ATUsed)
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
- }
-
- // Restore the return address only if the function isn't a leaf one.
- // lw $ra, stack_loc($sp)
- if (MFI->adjustsStack()) {
- ATUsed = expandRegLargeImmPair(Mips::SP, RAOffset, NewReg, NewImm, MBB,
- MBBI);
- BuildMI(MBB, MBBI, dl, TII.get(Mips::LW), Mips::RA)
- .addImm(NewImm).addReg(NewReg);
-
- // FIXME: change this when mips goes MC".
- if (ATUsed)
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
- }
-
// adjust stack : insert addi sp, sp, (imm)
if (NumBytes) {
ATUsed = expandRegLargeImmPair(Mips::SP, NumBytes, NewReg, NewImm, MBB,
@@ -390,6 +312,30 @@
}
void MipsFrameLowering::
+processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+ RegScavenger *RS) const {
+ MachineRegisterInfo& MRI = MF.getRegInfo();
+ MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
+
+ // FIXME: remove this code if register allocator can correctly mark
+ // $fp and $ra used or unused.
+
+ // Mark $fp and $ra as used or unused.
+ if (hasFP(MF))
+ MRI.setPhysRegUsed(Mips::FP);
+
+ // The register allocator might determine $ra is used after seeing
+ // instruction "jr $ra", but we do not want PrologEpilogInserter to insert
+ // instructions to save/restore $ra unless there is a function call.
+ // To correct this, $ra is explicitly marked unused if there is no
+ // function call.
+ if (MipsFI->hasCall())
+ MRI.setPhysRegUsed(Mips::RA);
+ else
+ MRI.setPhysRegUnused(Mips::RA);
+}
+
+void MipsFrameLowering::
processFunctionBeforeFrameFinalized(MachineFunction &MF) const {
const MipsRegisterInfo *RegInfo =
static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
diff --git a/lib/Target/Mips/MipsFrameLowering.h b/lib/Target/Mips/MipsFrameLowering.h
index 34647df..f42711d 100644
--- a/lib/Target/Mips/MipsFrameLowering.h
+++ b/lib/Target/Mips/MipsFrameLowering.h
@@ -40,6 +40,8 @@
bool hasFP(const MachineFunction &MF) const;
+ void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+ RegScavenger *RS) const;
void processFunctionBeforeFrameFinalized(MachineFunction &MF) const;
};
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index ea26d57..08da34b 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -1042,6 +1042,7 @@
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
bool IsPIC = getTargetMachine().getRelocationModel() == Reloc::PIC_;
+ MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
// Analyze operands of the call, assigning locations to each operand.
SmallVector<CCValAssign, 16> ArgLocs;
@@ -1066,6 +1067,8 @@
int LastArgStackLoc = 0;
unsigned FirstStackArgLoc = (Subtarget->isABI_EABI() ? 0 : 16);
+ MipsFI->setHasCall();
+
// Walk the register/memloc assignments, inserting copies/loads.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
SDValue Arg = OutVals[i];
@@ -1226,7 +1229,6 @@
// Function can have an arbitrary number of calls, so
// hold the LastArgStackLoc with the biggest offset.
int FI;
- MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
if (LastArgStackLoc >= MipsFI->getGPStackOffset()) {
LastArgStackLoc = (!LastArgStackLoc) ? (16) : (LastArgStackLoc+4);
// Create the frame index only once. SPOffset here can be anything
diff --git a/lib/Target/Mips/MipsMachineFunction.h b/lib/Target/Mips/MipsMachineFunction.h
index 3256193..c4d2cfe 100644
--- a/lib/Target/Mips/MipsMachineFunction.h
+++ b/lib/Target/Mips/MipsMachineFunction.h
@@ -27,14 +27,6 @@
class MipsFunctionInfo : public MachineFunctionInfo {
private:
- /// Holds for each function where on the stack the Frame Pointer must be
- /// saved. This is used on Prologue and Epilogue to emit FP save/restore
- int FPStackOffset;
-
- /// Holds for each function where on the stack the Return Address must be
- /// saved. This is used on Prologue and Epilogue to emit RA save/restore
- int RAStackOffset;
-
/// At each function entry, two special bitmask directives must be emitted
/// to help debugging, for CPU and FPU callee saved registers. Both need
/// the negative offset from the final stack size and its higher registers
@@ -94,19 +86,13 @@
bool HasCall; // True if function has a function call.
public:
MipsFunctionInfo(MachineFunction& MF)
- : FPStackOffset(0), RAStackOffset(0), CPUTopSavedRegOff(0),
+ : CPUTopSavedRegOff(0),
FPUTopSavedRegOff(0), GPHolder(-1,-1), HasLoadArgs(false),
HasStoreVarArgs(false), SRetReturnReg(0), GlobalBaseReg(0),
VarArgsFrameIndex(0), InArgFIRange(std::make_pair(-1, 0)),
OutArgFIRange(std::make_pair(-1, 0)), GPFI(0), HasCall(false)
{}
- int getFPStackOffset() const { return FPStackOffset; }
- void setFPStackOffset(int Off) { FPStackOffset = Off; }
-
- int getRAStackOffset() const { return RAStackOffset; }
- void setRAStackOffset(int Off) { RAStackOffset = Off; }
-
int getCPUTopSavedRegOff() const { return CPUTopSavedRegOff; }
void setCPUTopSavedRegOff(int Off) { CPUTopSavedRegOff = Off; }
diff --git a/lib/Target/Mips/MipsRegisterInfo.cpp b/lib/Target/Mips/MipsRegisterInfo.cpp
index 5a71745..eb11550 100644
--- a/lib/Target/Mips/MipsRegisterInfo.cpp
+++ b/lib/Target/Mips/MipsRegisterInfo.cpp
@@ -99,20 +99,20 @@
// Mips callee-save register range is $16-$23, $f20-$f30
static const unsigned SingleFloatOnlyCalleeSavedRegs[] = {
Mips::S0, Mips::S1, Mips::S2, Mips::S3,
- Mips::S4, Mips::S5, Mips::S6, Mips::S7,
+ Mips::S4, Mips::S5, Mips::S6, Mips::S7, Mips::FP, Mips::RA,
Mips::F20, Mips::F21, Mips::F22, Mips::F23, Mips::F24, Mips::F25,
Mips::F26, Mips::F27, Mips::F28, Mips::F29, Mips::F30, 0
};
static const unsigned BitMode32CalleeSavedRegs[] = {
Mips::S0, Mips::S1, Mips::S2, Mips::S3,
- Mips::S4, Mips::S5, Mips::S6, Mips::S7,
+ Mips::S4, Mips::S5, Mips::S6, Mips::S7, Mips::FP, Mips::RA,
Mips::F20, Mips::F22, Mips::F24, Mips::F26, Mips::F28, Mips::F30, 0
};
static const unsigned Mips32CalleeSavedRegs[] = {
Mips::S0, Mips::S1, Mips::S2, Mips::S3,
- Mips::S4, Mips::S5, Mips::S6, Mips::S7,
+ Mips::S4, Mips::S5, Mips::S6, Mips::S7, Mips::FP, Mips::RA,
Mips::D10, Mips::D11, Mips::D12, Mips::D13, Mips::D14, Mips::D15, 0
};