1 //===-- SparcFrameLowering.cpp - Sparc Frame Information ------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the Sparc implementation of TargetFrameLowering class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "SparcFrameLowering.h"
15 #include "SparcInstrInfo.h"
16 #include "SparcMachineFunctionInfo.h"
17 #include "llvm/CodeGen/MachineFrameInfo.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/CodeGen/MachineInstrBuilder.h"
20 #include "llvm/CodeGen/MachineModuleInfo.h"
21 #include "llvm/CodeGen/MachineRegisterInfo.h"
22 #include "llvm/IR/DataLayout.h"
23 #include "llvm/IR/Function.h"
24 #include "llvm/Support/CommandLine.h"
25 #include "llvm/Target/TargetOptions.h"
26
27 using namespace llvm;
28
emitPrologue(MachineFunction & MF) const29 void SparcFrameLowering::emitPrologue(MachineFunction &MF) const {
30 MachineBasicBlock &MBB = MF.front();
31 MachineFrameInfo *MFI = MF.getFrameInfo();
32 const SparcInstrInfo &TII =
33 *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
34 MachineBasicBlock::iterator MBBI = MBB.begin();
35 DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
36
37 // Get the number of bytes to allocate from the FrameInfo
38 int NumBytes = (int) MFI->getStackSize();
39
40 // Emit the correct save instruction based on the number of bytes in
41 // the frame. Minimum stack frame size according to V8 ABI is:
42 // 16 words for register window spill
43 // 1 word for address of returned aggregate-value
44 // + 6 words for passing parameters on the stack
45 // ----------
46 // 23 words * 4 bytes per word = 92 bytes
47 NumBytes += 92;
48
49 // Round up to next doubleword boundary -- a double-word boundary
50 // is required by the ABI.
51 NumBytes = (NumBytes + 7) & ~7;
52 NumBytes = -NumBytes;
53
54 if (NumBytes >= -4096) {
55 BuildMI(MBB, MBBI, dl, TII.get(SP::SAVEri), SP::O6)
56 .addReg(SP::O6).addImm(NumBytes);
57 } else {
58 // Emit this the hard way. This clobbers G1 which we always know is
59 // available here.
60 unsigned OffHi = (unsigned)NumBytes >> 10U;
61 BuildMI(MBB, MBBI, dl, TII.get(SP::SETHIi), SP::G1).addImm(OffHi);
62 // Emit G1 = G1 + I6
63 BuildMI(MBB, MBBI, dl, TII.get(SP::ORri), SP::G1)
64 .addReg(SP::G1).addImm(NumBytes & ((1 << 10)-1));
65 BuildMI(MBB, MBBI, dl, TII.get(SP::SAVErr), SP::O6)
66 .addReg(SP::O6).addReg(SP::G1);
67 }
68 }
69
70 void SparcFrameLowering::
eliminateCallFramePseudoInstr(MachineFunction & MF,MachineBasicBlock & MBB,MachineBasicBlock::iterator I) const71 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
72 MachineBasicBlock::iterator I) const {
73 MachineInstr &MI = *I;
74 DebugLoc dl = MI.getDebugLoc();
75 int Size = MI.getOperand(0).getImm();
76 if (MI.getOpcode() == SP::ADJCALLSTACKDOWN)
77 Size = -Size;
78 const SparcInstrInfo &TII =
79 *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
80 if (Size)
81 BuildMI(MBB, I, dl, TII.get(SP::ADDri), SP::O6).addReg(SP::O6).addImm(Size);
82 MBB.erase(I);
83 }
84
85
emitEpilogue(MachineFunction & MF,MachineBasicBlock & MBB) const86 void SparcFrameLowering::emitEpilogue(MachineFunction &MF,
87 MachineBasicBlock &MBB) const {
88 MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
89 const SparcInstrInfo &TII =
90 *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
91 DebugLoc dl = MBBI->getDebugLoc();
92 assert(MBBI->getOpcode() == SP::RETL &&
93 "Can only put epilog before 'retl' instruction!");
94 BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0)
95 .addReg(SP::G0);
96 }
97