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Move the code for initializing the global base reg out of

Browse Source 
X86ISelDAGToDAG.cpp and into X86InstrInfo.cpp. This will allow
it to be reused by FastISel.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56494 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2008-09-23 18:22:58 +00:00
parent 3ee8fc9649
commit 8b746969ba
3 changed files with 43 additions and 29 deletions
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38
lib/Target/X86/X86ISelDAGToDAG.cpp
View File

@ -232,8 +232,10 @@ namespace {
return CurDAG->getTargetConstant(Imm, MVT::i32);
}
/// getGlobalBaseReg - insert code into the entry mbb to materialize the PIC
/// base register. Return the virtual register that holds this value.
/// getGlobalBaseReg - Return an SDNode that returns the value of
/// the global base register. Output instructions required to
/// initialize the global base register, if necessary.
///
SDNode *getGlobalBaseReg();
/// getTruncateTo8Bit - return an SDNode that implements a subreg based
@ -1170,36 +1172,14 @@ bool X86DAGToDAGISel::TryFoldLoad(SDValue P, SDValue N,
return false;
}
/// getGlobalBaseReg - Output the instructions required to put the
/// base address to use for accessing globals into a register.
/// getGlobalBaseReg - Return an SDNode that returns the value of
/// the global base register. Output instructions required to
/// initialize the global base register, if necessary.
///
SDNode *X86DAGToDAGISel::getGlobalBaseReg() {
assert(!Subtarget->is64Bit() && "X86-64 PIC uses RIP relative addressing");
if (!GlobalBaseReg) {
// Insert the set of GlobalBaseReg into the first MBB of the function
MachineFunction *MF = BB->getParent();
MachineBasicBlock &FirstMBB = MF->front();
MachineBasicBlock::iterator MBBI = FirstMBB.begin();
MachineRegisterInfo &RegInfo = MF->getRegInfo();
unsigned PC = RegInfo.createVirtualRegister(X86::GR32RegisterClass);
const TargetInstrInfo *TII = TM.getInstrInfo();
// Operand of MovePCtoStack is completely ignored by asm printer. It's
// only used in JIT code emission as displacement to pc.
BuildMI(FirstMBB, MBBI, TII->get(X86::MOVPC32r), PC).addImm(0);
// If we're using vanilla 'GOT' PIC style, we should use relative addressing
// not to pc, but to _GLOBAL_ADDRESS_TABLE_ external
if (TM.getRelocationModel() == Reloc::PIC_ &&
Subtarget->isPICStyleGOT()) {
GlobalBaseReg = RegInfo.createVirtualRegister(X86::GR32RegisterClass);
BuildMI(FirstMBB, MBBI, TII->get(X86::ADD32ri), GlobalBaseReg)
.addReg(PC).addExternalSymbol("_GLOBAL_OFFSET_TABLE_");
} else {
GlobalBaseReg = PC;
}
}
if (!GlobalBaseReg)
GlobalBaseReg = TM.getInstrInfo()->initializeGlobalBaseReg(BB->getParent());
return CurDAG->getRegister(GlobalBaseReg, TLI.getPointerTy()).getNode();
}

29
lib/Target/X86/X86InstrInfo.cpp
View File

@ -2935,3 +2935,32 @@ unsigned X86InstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const {
}
return Size;
}
/// initializeGlobalBaseReg - Output the instructions required to put the
/// base address to use for accessing globals into a register.
///
unsigned X86InstrInfo::initializeGlobalBaseReg(MachineFunction *MF) const {
// Insert the set of GlobalBaseReg into the first MBB of the function
MachineBasicBlock &FirstMBB = MF->front();
MachineBasicBlock::iterator MBBI = FirstMBB.begin();
MachineRegisterInfo &RegInfo = MF->getRegInfo();
unsigned PC = RegInfo.createVirtualRegister(X86::GR32RegisterClass);
const TargetInstrInfo *TII = TM.getInstrInfo();
// Operand of MovePCtoStack is completely ignored by asm printer. It's
// only used in JIT code emission as displacement to pc.
BuildMI(FirstMBB, MBBI, TII->get(X86::MOVPC32r), PC).addImm(0);
// If we're using vanilla 'GOT' PIC style, we should use relative addressing
// not to pc, but to _GLOBAL_ADDRESS_TABLE_ external
if (TM.getRelocationModel() == Reloc::PIC_ &&
TM.getSubtarget<X86Subtarget>().isPICStyleGOT()) {
unsigned GlobalBaseReg =
RegInfo.createVirtualRegister(X86::GR32RegisterClass);
BuildMI(FirstMBB, MBBI, TII->get(X86::ADD32ri), GlobalBaseReg)
.addReg(PC).addExternalSymbol("_GLOBAL_OFFSET_TABLE_");
return GlobalBaseReg;
}
return PC;
}

5
lib/Target/X86/X86InstrInfo.h
View File

@ -414,6 +414,11 @@ public:
///
virtual unsigned GetInstSizeInBytes(const MachineInstr *MI) const;
/// initializeGlobalBaseReg - Output the instructions required to put the
/// base address to use for accessing globals into a register.
///
unsigned initializeGlobalBaseReg(MachineFunction *MF) const;
private:
MachineInstr* foldMemoryOperand(MachineFunction &MF,
MachineInstr* MI,