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ARM: lower tail calls correctly when using GHC calling convention.

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Patch by Ben Gamari.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223055 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tim Northover 2014-12-01 17:46:39 +00:00
parent c9605b6067
commit f7f88095a3
3 changed files with 76 additions and 38 deletions
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91
lib/Target/ARM/ARMFrameLowering.cpp
View File

@ -612,12 +612,60 @@ void ARMFrameLowering::emitPrologue(MachineFunction &MF) const {
AFI->setShouldRestoreSPFromFP(true);
}
void ARMFrameLowering::emitEpilogue(MachineFunction &MF,
// Resolve TCReturn pseudo-instruction
void ARMFrameLowering::fixTCReturn(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
assert(MBBI->isReturn() && "Can only insert epilog into returning blocks");
unsigned RetOpcode = MBBI->getOpcode();
DebugLoc dl = MBBI->getDebugLoc();
const ARMBaseInstrInfo &TII =
*static_cast<const ARMBaseInstrInfo *>(MF.getSubtarget().getInstrInfo());
if (!(RetOpcode == ARM::TCRETURNdi || RetOpcode == ARM::TCRETURNri))
return;
// Tail call return: adjust the stack pointer and jump to callee.
MBBI = MBB.getLastNonDebugInstr();
MachineOperand &JumpTarget = MBBI->getOperand(0);
// Jump to label or value in register.
if (RetOpcode == ARM::TCRETURNdi) {
unsigned TCOpcode = STI.isThumb() ?
(STI.isTargetMachO() ? ARM::tTAILJMPd : ARM::tTAILJMPdND) :
ARM::TAILJMPd;
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(TCOpcode));
if (JumpTarget.isGlobal())
MIB.addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
JumpTarget.getTargetFlags());
else {
assert(JumpTarget.isSymbol());
MIB.addExternalSymbol(JumpTarget.getSymbolName(),
JumpTarget.getTargetFlags());
}
// Add the default predicate in Thumb mode.
if (STI.isThumb()) MIB.addImm(ARMCC::AL).addReg(0);
} else if (RetOpcode == ARM::TCRETURNri) {
BuildMI(MBB, MBBI, dl,
TII.get(STI.isThumb() ? ARM::tTAILJMPr : ARM::TAILJMPr)).
addReg(JumpTarget.getReg(), RegState::Kill);
}
MachineInstr *NewMI = std::prev(MBBI);
for (unsigned i = 1, e = MBBI->getNumOperands(); i != e; ++i)
NewMI->addOperand(MBBI->getOperand(i));
// Delete the pseudo instruction TCRETURN.
MBB.erase(MBBI);
MBBI = NewMI;
}
void ARMFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
assert(MBBI->isReturn() && "Can only insert epilog into returning blocks");
DebugLoc dl = MBBI->getDebugLoc();
MachineFrameInfo *MFI = MF.getFrameInfo();
ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo();
@ -637,8 +685,10 @@ void ARMFrameLowering::emitEpilogue(MachineFunction &MF,
// All calls are tail calls in GHC calling conv, and functions have no
// prologue/epilogue.
if (MF.getFunction()->getCallingConv() == CallingConv::GHC)
if (MF.getFunction()->getCallingConv() == CallingConv::GHC) {
fixTCReturn(MF, MBB);
return;
}
if (!AFI->hasStackFrame()) {
if (NumBytes - ArgRegsSaveSize != 0)
@ -717,42 +767,7 @@ void ARMFrameLowering::emitEpilogue(MachineFunction &MF,
if (AFI->getGPRCalleeSavedArea1Size()) MBBI++;
}
if (RetOpcode == ARM::TCRETURNdi || RetOpcode == ARM::TCRETURNri) {
// Tail call return: adjust the stack pointer and jump to callee.
MBBI = MBB.getLastNonDebugInstr();
MachineOperand &JumpTarget = MBBI->getOperand(0);
// Jump to label or value in register.
if (RetOpcode == ARM::TCRETURNdi) {
unsigned TCOpcode = STI.isThumb() ?
(STI.isTargetMachO() ? ARM::tTAILJMPd : ARM::tTAILJMPdND) :
ARM::TAILJMPd;
MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl, TII.get(TCOpcode));
if (JumpTarget.isGlobal())
MIB.addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset(),
JumpTarget.getTargetFlags());
else {
assert(JumpTarget.isSymbol());
MIB.addExternalSymbol(JumpTarget.getSymbolName(),
JumpTarget.getTargetFlags());
}
// Add the default predicate in Thumb mode.
if (STI.isThumb()) MIB.addImm(ARMCC::AL).addReg(0);
} else if (RetOpcode == ARM::TCRETURNri) {
BuildMI(MBB, MBBI, dl,
TII.get(STI.isThumb() ? ARM::tTAILJMPr : ARM::TAILJMPr)).
addReg(JumpTarget.getReg(), RegState::Kill);
}
MachineInstr *NewMI = std::prev(MBBI);
for (unsigned i = 1, e = MBBI->getNumOperands(); i != e; ++i)
NewMI->addOperand(MBBI->getOperand(i));
// Delete the pseudo instruction TCRETURN.
MBB.erase(MBBI);
MBBI = NewMI;
}
fixTCReturn(MF, MBB);
if (ArgRegsSaveSize)
emitSPUpdate(isARM, MBB, MBBI, dl, TII, ArgRegsSaveSize);

2
lib/Target/ARM/ARMFrameLowering.h
View File

@ -31,6 +31,8 @@ public:
void emitPrologue(MachineFunction &MF) const override;
void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
void fixTCReturn(MachineFunction &MF, MachineBasicBlock &MBB) const;
bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI,

21
test/CodeGen/ARM/ghc-tcreturn-lowered.ll Normal file
View File

@ -0,0 +1,21 @@
; RUN: llc -mtriple=thumbv7-eabi -o - %s | FileCheck %s
declare cc 10 void @g()
define cc 10 void @test_direct_tail() {
; CHECK-LABEL: test_direct_tail:
; CHECK: b g
tail call cc10 void @g()
ret void
}
@ind_func = global void()* zeroinitializer
define cc 10 void @test_indirect_tail() {
; CHECK-LABEL: test_indirect_tail:
; CHECK: bx {{r[0-9]+}}
%func = load void()** @ind_func
tail call cc10 void()* %func()
ret void
}