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Implemented functions for emitting prologues and epilogues;

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removed EBP from the list of callee-saved registers (it isn't one).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4929 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Misha Brukman 2002-12-04 23:57:03 +00:00
parent 1f283ef3e5
commit 2adb3959f6
2 changed files with 62 additions and 1 deletions
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55
lib/Target/X86/X86RegisterInfo.cpp
View File

@ -58,7 +58,7 @@ unsigned X86RegisterInfo::getStackPointer() const {
}
const unsigned* X86RegisterInfo::getCalleeSaveRegs() const {
static const unsigned CalleeSaveRegs[] = { X86::ESI, X86::EDI, X86::EBX, X86::EBP,
static const unsigned CalleeSaveRegs[] = { X86::ESI, X86::EDI, X86::EBX,
MRegisterInfo::NoRegister };
return CalleeSaveRegs;
}
@ -69,3 +69,56 @@ const unsigned* X86RegisterInfo::getCallerSaveRegs() const {
MRegisterInfo::NoRegister };
return CallerSaveRegs;
}
MachineBasicBlock::iterator
X86RegisterInfo::emitPrologue(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI,
unsigned numBytes) const
{
MachineInstr *MI;
// PUSH ebp
MI = BuildMI (X86::PUSHr32, 1).addReg(X86::EBP);
MBBI = ++(MBB->insert(MBBI, MI));
// MOV ebp, esp
MI = BuildMI (X86::MOVrr32, 2).addReg(X86::EBP).addReg(X86::ESP);
MBBI = ++(MBB->insert(MBBI, MI));
// adjust stack pointer
MI = BuildMI(X86::SUBri32, 2).addReg(X86::ESP).addZImm(numBytes);
MBBI = ++(MBB->insert(MBBI, MI));
// PUSH all callee-save registers
const unsigned* regs = getCalleeSaveRegs();
while (*regs) {
MI = BuildMI(X86::PUSHr32, 1).addReg(*regs);
MBBI = ++(MBB->insert(MBBI, MI));
++regs;
}
return MBBI;
}
MachineBasicBlock::iterator
X86RegisterInfo::emitEpilogue(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI,
unsigned numBytes) const
{
MachineInstr *MI;
// POP all callee-save registers in REVERSE ORDER
static const unsigned regs[] = { X86::EBX, X86::EDI, X86::ESI,
MRegisterInfo::NoRegister };
unsigned idx = 0;
while (regs[idx]) {
MI = BuildMI(X86::POPr32, 1).addReg(regs[idx++]);
MBBI = ++(MBB->insert(MBBI, MI));
}
// insert LEAVE
MI = BuildMI(X86::LEAVE, 0);
MBBI = ++(MBB->insert(MBBI, MI));
return MBBI;
}

8
lib/Target/X86/X86RegisterInfo.h
View File

@ -35,6 +35,14 @@ struct X86RegisterInfo : public MRegisterInfo {
const unsigned* getCalleeSaveRegs() const;
const unsigned* getCallerSaveRegs() const;
MachineBasicBlock::iterator emitPrologue(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI,
unsigned numBytes) const;
MachineBasicBlock::iterator emitEpilogue(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI,
unsigned numBytes) const;
/// Returns register class appropriate for input SSA register
///
const TargetRegisterClass *getClassForReg(unsigned Reg) const;