xref: /llvm-project/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp (revision 13f18e853fcc1ad04d7d06786de0c647e0924aae)
1 //===- PPCRegisterInfo.cpp - PowerPC Register Information -------*- C++ -*-===//
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 PowerPC implementation of the TargetRegisterInfo
11 // class.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #define DEBUG_TYPE "reginfo"
16 #include "PPC.h"
17 #include "PPCInstrBuilder.h"
18 #include "PPCMachineFunctionInfo.h"
19 #include "PPCRegisterInfo.h"
20 #include "PPCFrameInfo.h"
21 #include "PPCSubtarget.h"
22 #include "llvm/CallingConv.h"
23 #include "llvm/Constants.h"
24 #include "llvm/Function.h"
25 #include "llvm/Type.h"
26 #include "llvm/CodeGen/ValueTypes.h"
27 #include "llvm/CodeGen/MachineInstrBuilder.h"
28 #include "llvm/CodeGen/MachineModuleInfo.h"
29 #include "llvm/CodeGen/MachineFunction.h"
30 #include "llvm/CodeGen/MachineFrameInfo.h"
31 #include "llvm/CodeGen/MachineLocation.h"
32 #include "llvm/CodeGen/MachineRegisterInfo.h"
33 #include "llvm/CodeGen/RegisterScavenging.h"
34 #include "llvm/Target/TargetFrameInfo.h"
35 #include "llvm/Target/TargetInstrInfo.h"
36 #include "llvm/Target/TargetMachine.h"
37 #include "llvm/Target/TargetOptions.h"
38 #include "llvm/Support/CommandLine.h"
39 #include "llvm/Support/Debug.h"
40 #include "llvm/Support/MathExtras.h"
41 #include "llvm/ADT/BitVector.h"
42 #include "llvm/ADT/STLExtras.h"
43 #include <cstdlib>
44 using namespace llvm;
45 
46 // FIXME This disables some code that aligns the stack to a boundary
47 // bigger than the default (16 bytes on Darwin) when there is a stack local
48 // of greater alignment.  This does not currently work, because the delta
49 // between old and new stack pointers is added to offsets that reference
50 // incoming parameters after the prolog is generated, and the code that
51 // does that doesn't handle a variable delta.  You don't want to do that
52 // anyway; a better approach is to reserve another register that retains
53 // to the incoming stack pointer, and reference parameters relative to that.
54 #define ALIGN_STACK 0
55 
56 // FIXME (64-bit): Eventually enable by default.
57 cl::opt<bool> EnablePPC32RS("enable-ppc32-regscavenger",
58                             cl::init(false),
59                             cl::desc("Enable PPC32 register scavenger"),
60                             cl::Hidden);
61 cl::opt<bool> EnablePPC64RS("enable-ppc64-regscavenger",
62                             cl::init(false),
63                             cl::desc("Enable PPC64 register scavenger"),
64                             cl::Hidden);
65 #define EnableRegisterScavenging \
66   ((EnablePPC32RS && !Subtarget.isPPC64()) || \
67    (EnablePPC64RS && Subtarget.isPPC64()))
68 
69 // FIXME (64-bit): Should be inlined.
70 bool
71 PPCRegisterInfo::requiresRegisterScavenging(const MachineFunction &) const {
72   return EnableRegisterScavenging;
73 }
74 
75 /// getRegisterNumbering - Given the enum value for some register, e.g.
76 /// PPC::F14, return the number that it corresponds to (e.g. 14).
77 unsigned PPCRegisterInfo::getRegisterNumbering(unsigned RegEnum) {
78   using namespace PPC;
79   switch (RegEnum) {
80   case 0: return 0;
81   case R0 :  case X0 :  case F0 :  case V0 : case CR0:  case CR0LT: return  0;
82   case R1 :  case X1 :  case F1 :  case V1 : case CR1:  case CR0GT: return  1;
83   case R2 :  case X2 :  case F2 :  case V2 : case CR2:  case CR0EQ: return  2;
84   case R3 :  case X3 :  case F3 :  case V3 : case CR3:  case CR0UN: return  3;
85   case R4 :  case X4 :  case F4 :  case V4 : case CR4:  case CR1LT: return  4;
86   case R5 :  case X5 :  case F5 :  case V5 : case CR5:  case CR1GT: return  5;
87   case R6 :  case X6 :  case F6 :  case V6 : case CR6:  case CR1EQ: return  6;
88   case R7 :  case X7 :  case F7 :  case V7 : case CR7:  case CR1UN: return  7;
89   case R8 :  case X8 :  case F8 :  case V8 : case CR2LT: return  8;
90   case R9 :  case X9 :  case F9 :  case V9 : case CR2GT: return  9;
91   case R10:  case X10:  case F10:  case V10: case CR2EQ: return 10;
92   case R11:  case X11:  case F11:  case V11: case CR2UN: return 11;
93   case R12:  case X12:  case F12:  case V12: case CR3LT: return 12;
94   case R13:  case X13:  case F13:  case V13: case CR3GT: return 13;
95   case R14:  case X14:  case F14:  case V14: case CR3EQ: return 14;
96   case R15:  case X15:  case F15:  case V15: case CR3UN: return 15;
97   case R16:  case X16:  case F16:  case V16: case CR4LT: return 16;
98   case R17:  case X17:  case F17:  case V17: case CR4GT: return 17;
99   case R18:  case X18:  case F18:  case V18: case CR4EQ: return 18;
100   case R19:  case X19:  case F19:  case V19: case CR4UN: return 19;
101   case R20:  case X20:  case F20:  case V20: case CR5LT: return 20;
102   case R21:  case X21:  case F21:  case V21: case CR5GT: return 21;
103   case R22:  case X22:  case F22:  case V22: case CR5EQ: return 22;
104   case R23:  case X23:  case F23:  case V23: case CR5UN: return 23;
105   case R24:  case X24:  case F24:  case V24: case CR6LT: return 24;
106   case R25:  case X25:  case F25:  case V25: case CR6GT: return 25;
107   case R26:  case X26:  case F26:  case V26: case CR6EQ: return 26;
108   case R27:  case X27:  case F27:  case V27: case CR6UN: return 27;
109   case R28:  case X28:  case F28:  case V28: case CR7LT: return 28;
110   case R29:  case X29:  case F29:  case V29: case CR7GT: return 29;
111   case R30:  case X30:  case F30:  case V30: case CR7EQ: return 30;
112   case R31:  case X31:  case F31:  case V31: case CR7UN: return 31;
113   default:
114     cerr << "Unhandled reg in PPCRegisterInfo::getRegisterNumbering!\n";
115     abort();
116   }
117 }
118 
119 PPCRegisterInfo::PPCRegisterInfo(const PPCSubtarget &ST,
120                                  const TargetInstrInfo &tii)
121   : PPCGenRegisterInfo(PPC::ADJCALLSTACKDOWN, PPC::ADJCALLSTACKUP),
122     Subtarget(ST), TII(tii) {
123   ImmToIdxMap[PPC::LD]   = PPC::LDX;    ImmToIdxMap[PPC::STD]  = PPC::STDX;
124   ImmToIdxMap[PPC::LBZ]  = PPC::LBZX;   ImmToIdxMap[PPC::STB]  = PPC::STBX;
125   ImmToIdxMap[PPC::LHZ]  = PPC::LHZX;   ImmToIdxMap[PPC::LHA]  = PPC::LHAX;
126   ImmToIdxMap[PPC::LWZ]  = PPC::LWZX;   ImmToIdxMap[PPC::LWA]  = PPC::LWAX;
127   ImmToIdxMap[PPC::LFS]  = PPC::LFSX;   ImmToIdxMap[PPC::LFD]  = PPC::LFDX;
128   ImmToIdxMap[PPC::STH]  = PPC::STHX;   ImmToIdxMap[PPC::STW]  = PPC::STWX;
129   ImmToIdxMap[PPC::STFS] = PPC::STFSX;  ImmToIdxMap[PPC::STFD] = PPC::STFDX;
130   ImmToIdxMap[PPC::ADDI] = PPC::ADD4;
131 
132   // 64-bit
133   ImmToIdxMap[PPC::LHA8] = PPC::LHAX8; ImmToIdxMap[PPC::LBZ8] = PPC::LBZX8;
134   ImmToIdxMap[PPC::LHZ8] = PPC::LHZX8; ImmToIdxMap[PPC::LWZ8] = PPC::LWZX8;
135   ImmToIdxMap[PPC::STB8] = PPC::STBX8; ImmToIdxMap[PPC::STH8] = PPC::STHX8;
136   ImmToIdxMap[PPC::STW8] = PPC::STWX8; ImmToIdxMap[PPC::STDU] = PPC::STDUX;
137   ImmToIdxMap[PPC::ADDI8] = PPC::ADD8; ImmToIdxMap[PPC::STD_32] = PPC::STDX_32;
138 }
139 
140 const unsigned*
141 PPCRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
142   // 32-bit Darwin calling convention.
143   static const unsigned Macho32_CalleeSavedRegs[] = {
144               PPC::R13, PPC::R14, PPC::R15,
145     PPC::R16, PPC::R17, PPC::R18, PPC::R19,
146     PPC::R20, PPC::R21, PPC::R22, PPC::R23,
147     PPC::R24, PPC::R25, PPC::R26, PPC::R27,
148     PPC::R28, PPC::R29, PPC::R30, PPC::R31,
149 
150     PPC::F14, PPC::F15, PPC::F16, PPC::F17,
151     PPC::F18, PPC::F19, PPC::F20, PPC::F21,
152     PPC::F22, PPC::F23, PPC::F24, PPC::F25,
153     PPC::F26, PPC::F27, PPC::F28, PPC::F29,
154     PPC::F30, PPC::F31,
155 
156     PPC::CR2, PPC::CR3, PPC::CR4,
157     PPC::V20, PPC::V21, PPC::V22, PPC::V23,
158     PPC::V24, PPC::V25, PPC::V26, PPC::V27,
159     PPC::V28, PPC::V29, PPC::V30, PPC::V31,
160 
161     PPC::CR2LT, PPC::CR2GT, PPC::CR2EQ, PPC::CR2UN,
162     PPC::CR3LT, PPC::CR3GT, PPC::CR3EQ, PPC::CR3UN,
163     PPC::CR4LT, PPC::CR4GT, PPC::CR4EQ, PPC::CR4UN,
164 
165     PPC::LR,  0
166   };
167 
168   static const unsigned ELF32_CalleeSavedRegs[] = {
169               PPC::R13, PPC::R14, PPC::R15,
170     PPC::R16, PPC::R17, PPC::R18, PPC::R19,
171     PPC::R20, PPC::R21, PPC::R22, PPC::R23,
172     PPC::R24, PPC::R25, PPC::R26, PPC::R27,
173     PPC::R28, PPC::R29, PPC::R30, PPC::R31,
174 
175                                   PPC::F9,
176     PPC::F10, PPC::F11, PPC::F12, PPC::F13,
177     PPC::F14, PPC::F15, PPC::F16, PPC::F17,
178     PPC::F18, PPC::F19, PPC::F20, PPC::F21,
179     PPC::F22, PPC::F23, PPC::F24, PPC::F25,
180     PPC::F26, PPC::F27, PPC::F28, PPC::F29,
181     PPC::F30, PPC::F31,
182 
183     PPC::CR2, PPC::CR3, PPC::CR4,
184     PPC::V20, PPC::V21, PPC::V22, PPC::V23,
185     PPC::V24, PPC::V25, PPC::V26, PPC::V27,
186     PPC::V28, PPC::V29, PPC::V30, PPC::V31,
187 
188     PPC::CR2LT, PPC::CR2GT, PPC::CR2EQ, PPC::CR2UN,
189     PPC::CR3LT, PPC::CR3GT, PPC::CR3EQ, PPC::CR3UN,
190     PPC::CR4LT, PPC::CR4GT, PPC::CR4EQ, PPC::CR4UN,
191 
192     PPC::LR,  0
193   };
194   // 64-bit Darwin calling convention.
195   static const unsigned Macho64_CalleeSavedRegs[] = {
196     PPC::X14, PPC::X15,
197     PPC::X16, PPC::X17, PPC::X18, PPC::X19,
198     PPC::X20, PPC::X21, PPC::X22, PPC::X23,
199     PPC::X24, PPC::X25, PPC::X26, PPC::X27,
200     PPC::X28, PPC::X29, PPC::X30, PPC::X31,
201 
202     PPC::F14, PPC::F15, PPC::F16, PPC::F17,
203     PPC::F18, PPC::F19, PPC::F20, PPC::F21,
204     PPC::F22, PPC::F23, PPC::F24, PPC::F25,
205     PPC::F26, PPC::F27, PPC::F28, PPC::F29,
206     PPC::F30, PPC::F31,
207 
208     PPC::CR2, PPC::CR3, PPC::CR4,
209     PPC::V20, PPC::V21, PPC::V22, PPC::V23,
210     PPC::V24, PPC::V25, PPC::V26, PPC::V27,
211     PPC::V28, PPC::V29, PPC::V30, PPC::V31,
212 
213     PPC::CR2LT, PPC::CR2GT, PPC::CR2EQ, PPC::CR2UN,
214     PPC::CR3LT, PPC::CR3GT, PPC::CR3EQ, PPC::CR3UN,
215     PPC::CR4LT, PPC::CR4GT, PPC::CR4EQ, PPC::CR4UN,
216 
217     PPC::LR8,  0
218   };
219 
220   if (Subtarget.isMachoABI())
221     return Subtarget.isPPC64() ? Macho64_CalleeSavedRegs :
222                                  Macho32_CalleeSavedRegs;
223 
224   // ELF 32.
225   return ELF32_CalleeSavedRegs;
226 }
227 
228 const TargetRegisterClass* const*
229 PPCRegisterInfo::getCalleeSavedRegClasses(const MachineFunction *MF) const {
230   // 32-bit Macho calling convention.
231   static const TargetRegisterClass * const Macho32_CalleeSavedRegClasses[] = {
232                        &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
233     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
234     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
235     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
236     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
237 
238     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
239     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
240     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
241     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
242     &PPC::F8RCRegClass,&PPC::F8RCRegClass,
243 
244     &PPC::CRRCRegClass,&PPC::CRRCRegClass,&PPC::CRRCRegClass,
245 
246     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
247     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
248     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
249 
250     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
251     &PPC::CRBITRCRegClass,
252     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
253     &PPC::CRBITRCRegClass,
254     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
255     &PPC::CRBITRCRegClass,
256 
257     &PPC::GPRCRegClass, 0
258   };
259 
260   static const TargetRegisterClass * const ELF32_CalleeSavedRegClasses[] = {
261                        &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
262     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
263     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
264     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
265     &PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,&PPC::GPRCRegClass,
266 
267                                                              &PPC::F8RCRegClass,
268     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
269     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
270     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
271     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
272     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
273     &PPC::F8RCRegClass,&PPC::F8RCRegClass,
274 
275     &PPC::CRRCRegClass,&PPC::CRRCRegClass,&PPC::CRRCRegClass,
276 
277     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
278     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
279     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
280 
281     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
282     &PPC::CRBITRCRegClass,
283     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
284     &PPC::CRBITRCRegClass,
285     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
286     &PPC::CRBITRCRegClass,
287 
288     &PPC::GPRCRegClass, 0
289   };
290 
291   // 64-bit Macho calling convention.
292   static const TargetRegisterClass * const Macho64_CalleeSavedRegClasses[] = {
293     &PPC::G8RCRegClass,&PPC::G8RCRegClass,
294     &PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,
295     &PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,
296     &PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,
297     &PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,&PPC::G8RCRegClass,
298 
299     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
300     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
301     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
302     &PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,&PPC::F8RCRegClass,
303     &PPC::F8RCRegClass,&PPC::F8RCRegClass,
304 
305     &PPC::CRRCRegClass,&PPC::CRRCRegClass,&PPC::CRRCRegClass,
306 
307     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
308     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
309     &PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,&PPC::VRRCRegClass,
310 
311     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
312     &PPC::CRBITRCRegClass,
313     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
314     &PPC::CRBITRCRegClass,
315     &PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,&PPC::CRBITRCRegClass,
316     &PPC::CRBITRCRegClass,
317 
318     &PPC::G8RCRegClass, 0
319   };
320 
321   if (Subtarget.isMachoABI())
322     return Subtarget.isPPC64() ? Macho64_CalleeSavedRegClasses :
323                                  Macho32_CalleeSavedRegClasses;
324 
325   // ELF 32.
326   return ELF32_CalleeSavedRegClasses;
327 }
328 
329 // needsFP - Return true if the specified function should have a dedicated frame
330 // pointer register.  This is true if the function has variable sized allocas or
331 // if frame pointer elimination is disabled.
332 //
333 static bool needsFP(const MachineFunction &MF) {
334   const MachineFrameInfo *MFI = MF.getFrameInfo();
335   return NoFramePointerElim || MFI->hasVarSizedObjects() ||
336     (PerformTailCallOpt && MF.getInfo<PPCFunctionInfo>()->hasFastCall());
337 }
338 
339 static bool spillsCR(const MachineFunction &MF) {
340   const PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
341   return FuncInfo->isCRSpilled();
342 }
343 
344 BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
345   BitVector Reserved(getNumRegs());
346   Reserved.set(PPC::R0);
347   Reserved.set(PPC::R1);
348   Reserved.set(PPC::LR);
349   Reserved.set(PPC::LR8);
350   Reserved.set(PPC::RM);
351 
352   // In Linux, r2 is reserved for the OS.
353   if (!Subtarget.isDarwin())
354     Reserved.set(PPC::R2);
355 
356   // On PPC64, r13 is the thread pointer. Never allocate this register. Note
357   // that this is over conservative, as it also prevents allocation of R31 when
358   // the FP is not needed.
359   if (Subtarget.isPPC64()) {
360     Reserved.set(PPC::R13);
361     Reserved.set(PPC::R31);
362 
363     if (!EnableRegisterScavenging)
364       Reserved.set(PPC::R0);    // FIXME (64-bit): Remove
365 
366     Reserved.set(PPC::X0);
367     Reserved.set(PPC::X1);
368     Reserved.set(PPC::X13);
369     Reserved.set(PPC::X31);
370   }
371 
372   if (needsFP(MF))
373     Reserved.set(PPC::R31);
374 
375   return Reserved;
376 }
377 
378 //===----------------------------------------------------------------------===//
379 // Stack Frame Processing methods
380 //===----------------------------------------------------------------------===//
381 
382 // hasFP - Return true if the specified function actually has a dedicated frame
383 // pointer register.  This is true if the function needs a frame pointer and has
384 // a non-zero stack size.
385 bool PPCRegisterInfo::hasFP(const MachineFunction &MF) const {
386   const MachineFrameInfo *MFI = MF.getFrameInfo();
387   return MFI->getStackSize() && needsFP(MF);
388 }
389 
390 /// MustSaveLR - Return true if this function requires that we save the LR
391 /// register onto the stack in the prolog and restore it in the epilog of the
392 /// function.
393 static bool MustSaveLR(const MachineFunction &MF, unsigned LR) {
394   const PPCFunctionInfo *MFI = MF.getInfo<PPCFunctionInfo>();
395 
396   // We need a save/restore of LR if there is any def of LR (which is
397   // defined by calls, including the PIC setup sequence), or if there is
398   // some use of the LR stack slot (e.g. for builtin_return_address).
399   // (LR comes in 32 and 64 bit versions.)
400   MachineRegisterInfo::def_iterator RI = MF.getRegInfo().def_begin(LR);
401   return RI !=MF.getRegInfo().def_end() || MFI->isLRStoreRequired();
402 }
403 
404 
405 
406 void PPCRegisterInfo::
407 eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
408                               MachineBasicBlock::iterator I) const {
409   if (PerformTailCallOpt && I->getOpcode() == PPC::ADJCALLSTACKUP) {
410     // Add (actually subtract) back the amount the callee popped on return.
411     if (int CalleeAmt =  I->getOperand(1).getImm()) {
412       bool is64Bit = Subtarget.isPPC64();
413       CalleeAmt *= -1;
414       unsigned StackReg = is64Bit ? PPC::X1 : PPC::R1;
415       unsigned TmpReg = is64Bit ? PPC::X0 : PPC::R0;
416       unsigned ADDIInstr = is64Bit ? PPC::ADDI8 : PPC::ADDI;
417       unsigned ADDInstr = is64Bit ? PPC::ADD8 : PPC::ADD4;
418       unsigned LISInstr = is64Bit ? PPC::LIS8 : PPC::LIS;
419       unsigned ORIInstr = is64Bit ? PPC::ORI8 : PPC::ORI;
420 
421       if (isInt16(CalleeAmt)) {
422         BuildMI(MBB, I, TII.get(ADDIInstr), StackReg).addReg(StackReg).
423           addImm(CalleeAmt);
424       } else {
425         MachineBasicBlock::iterator MBBI = I;
426         BuildMI(MBB, MBBI, TII.get(LISInstr), TmpReg)
427           .addImm(CalleeAmt >> 16);
428         BuildMI(MBB, MBBI, TII.get(ORIInstr), TmpReg)
429           .addReg(TmpReg, false, false, true)
430           .addImm(CalleeAmt & 0xFFFF);
431         BuildMI(MBB, MBBI, TII.get(ADDInstr))
432           .addReg(StackReg)
433           .addReg(StackReg)
434           .addReg(TmpReg);
435       }
436     }
437   }
438   // Simply discard ADJCALLSTACKDOWN, ADJCALLSTACKUP instructions.
439   MBB.erase(I);
440 }
441 
442 /// findScratchRegister - Find a 'free' PPC register. Try for a call-clobbered
443 /// register first and then a spilled callee-saved register if that fails.
444 static
445 unsigned findScratchRegister(MachineBasicBlock::iterator II, RegScavenger *RS,
446                              const TargetRegisterClass *RC, int SPAdj) {
447   assert(RS && "Register scavenging must be on");
448   unsigned Reg = RS->FindUnusedReg(RC, true);
449   // FIXME: move ARM callee-saved reg scan to target independent code, then
450   // search for already spilled CS register here.
451   if (Reg == 0)
452     Reg = RS->scavengeRegister(RC, II, SPAdj);
453   return Reg;
454 }
455 
456 /// lowerDynamicAlloc - Generate the code for allocating an object in the
457 /// current frame.  The sequence of code with be in the general form
458 ///
459 ///   addi   R0, SP, #frameSize ; get the address of the previous frame
460 ///   stwxu  R0, SP, Rnegsize   ; add and update the SP with the negated size
461 ///   addi   Rnew, SP, #maxCalFrameSize ; get the top of the allocation
462 ///
463 void PPCRegisterInfo::lowerDynamicAlloc(MachineBasicBlock::iterator II,
464                                         int SPAdj, RegScavenger *RS) const {
465   // Get the instruction.
466   MachineInstr &MI = *II;
467   // Get the instruction's basic block.
468   MachineBasicBlock &MBB = *MI.getParent();
469   // Get the basic block's function.
470   MachineFunction &MF = *MBB.getParent();
471   // Get the frame info.
472   MachineFrameInfo *MFI = MF.getFrameInfo();
473   // Determine whether 64-bit pointers are used.
474   bool LP64 = Subtarget.isPPC64();
475 
476   // Get the maximum call stack size.
477   unsigned maxCallFrameSize = MFI->getMaxCallFrameSize();
478   // Get the total frame size.
479   unsigned FrameSize = MFI->getStackSize();
480 
481   // Get stack alignments.
482   unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
483   unsigned MaxAlign = MFI->getMaxAlignment();
484   assert(MaxAlign <= TargetAlign &&
485          "Dynamic alloca with large aligns not supported");
486 
487   // Determine the previous frame's address.  If FrameSize can't be
488   // represented as 16 bits or we need special alignment, then we load the
489   // previous frame's address from 0(SP).  Why not do an addis of the hi?
490   // Because R0 is our only safe tmp register and addi/addis treat R0 as zero.
491   // Constructing the constant and adding would take 3 instructions.
492   // Fortunately, a frame greater than 32K is rare.
493   const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
494   const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
495   const TargetRegisterClass *RC = LP64 ? G8RC : GPRC;
496 
497   // FIXME (64-bit): Use "findScratchRegister"
498   unsigned Reg;
499   if (EnableRegisterScavenging)
500     Reg = findScratchRegister(II, RS, RC, SPAdj);
501   else
502     Reg = PPC::R0;
503 
504   if (MaxAlign < TargetAlign && isInt16(FrameSize)) {
505     BuildMI(MBB, II, TII.get(PPC::ADDI), Reg)
506       .addReg(PPC::R31)
507       .addImm(FrameSize);
508   } else if (LP64) {
509     if (EnableRegisterScavenging) // FIXME (64-bit): Use "true" part.
510       BuildMI(MBB, II, TII.get(PPC::LD), Reg)
511         .addImm(0)
512         .addReg(PPC::X1);
513     else
514       BuildMI(MBB, II, TII.get(PPC::LD), PPC::X0)
515         .addImm(0)
516         .addReg(PPC::X1);
517   } else {
518     BuildMI(MBB, II, TII.get(PPC::LWZ), Reg)
519       .addImm(0)
520       .addReg(PPC::R1);
521   }
522 
523   // Grow the stack and update the stack pointer link, then determine the
524   // address of new allocated space.
525   if (LP64) {
526     if (EnableRegisterScavenging) // FIXME (64-bit): Use "true" part.
527       BuildMI(MBB, II, TII.get(PPC::STDUX))
528         .addReg(Reg, false, false, true)
529         .addReg(PPC::X1)
530         .addReg(MI.getOperand(1).getReg());
531     else
532       BuildMI(MBB, II, TII.get(PPC::STDUX))
533         .addReg(PPC::X0, false, false, true)
534         .addReg(PPC::X1)
535         .addReg(MI.getOperand(1).getReg());
536 
537     if (!MI.getOperand(1).isKill())
538       BuildMI(MBB, II, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
539         .addReg(PPC::X1)
540         .addImm(maxCallFrameSize);
541     else
542       // Implicitly kill the register.
543       BuildMI(MBB, II, TII.get(PPC::ADDI8), MI.getOperand(0).getReg())
544         .addReg(PPC::X1)
545         .addImm(maxCallFrameSize)
546         .addReg(MI.getOperand(1).getReg(), false, true, true);
547   } else {
548     BuildMI(MBB, II, TII.get(PPC::STWUX))
549       .addReg(Reg, false, false, true)
550       .addReg(PPC::R1)
551       .addReg(MI.getOperand(1).getReg());
552 
553     if (!MI.getOperand(1).isKill())
554       BuildMI(MBB, II, TII.get(PPC::ADDI), MI.getOperand(0).getReg())
555         .addReg(PPC::R1)
556         .addImm(maxCallFrameSize);
557     else
558       // Implicitly kill the register.
559       BuildMI(MBB, II, TII.get(PPC::ADDI), MI.getOperand(0).getReg())
560         .addReg(PPC::R1)
561         .addImm(maxCallFrameSize)
562         .addReg(MI.getOperand(1).getReg(), false, true, true);
563   }
564 
565   // Discard the DYNALLOC instruction.
566   MBB.erase(II);
567 }
568 
569 /// lowerCRSpilling - Generate the code for spilling a CR register. Instead of
570 /// reserving a whole register (R0), we scrounge for one here. This generates
571 /// code like this:
572 ///
573 ///   mfcr rA                  ; Move the conditional register into GPR rA.
574 ///   rlwinm rA, rA, SB, 0, 31 ; Shift the bits left so they are in CR0's slot.
575 ///   stw rA, FI               ; Store rA to the frame.
576 ///
577 void PPCRegisterInfo::lowerCRSpilling(MachineBasicBlock::iterator II,
578                                       unsigned FrameIndex, int SPAdj,
579                                       RegScavenger *RS) const {
580   // Get the instruction.
581   MachineInstr &MI = *II;       // ; SPILL_CR <SrcReg>, <offset>, <FI>
582   // Get the instruction's basic block.
583   MachineBasicBlock &MBB = *MI.getParent();
584 
585   const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
586   const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
587   const TargetRegisterClass *RC = Subtarget.isPPC64() ? G8RC : GPRC;
588   unsigned Reg = findScratchRegister(II, RS, RC, SPAdj);
589 
590   // We need to store the CR in the low 4-bits of the saved value. First, issue
591   // an MFCR to save all of the CRBits. Add an implicit kill of the CR.
592   if (!MI.getOperand(0).isKill())
593     BuildMI(MBB, II, TII.get(PPC::MFCR), Reg);
594   else
595     // Implicitly kill the CR register.
596     BuildMI(MBB, II, TII.get(PPC::MFCR), Reg)
597       .addReg(MI.getOperand(0).getReg(), false, true, true);
598 
599   // If the saved register wasn't CR0, shift the bits left so that they are in
600   // CR0's slot.
601   unsigned SrcReg = MI.getOperand(0).getReg();
602   if (SrcReg != PPC::CR0)
603     // rlwinm rA, rA, ShiftBits, 0, 31.
604     BuildMI(MBB, II, TII.get(PPC::RLWINM), Reg)
605       .addReg(Reg, false, false, true)
606       .addImm(PPCRegisterInfo::getRegisterNumbering(SrcReg) * 4)
607       .addImm(0)
608       .addImm(31);
609 
610   addFrameReference(BuildMI(MBB, II, TII.get(PPC::STW))
611                     .addReg(Reg, false, false, MI.getOperand(1).getImm()),
612                     FrameIndex);
613 
614   // Discard the pseudo instruction.
615   MBB.erase(II);
616 }
617 
618 void PPCRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
619                                           int SPAdj, RegScavenger *RS) const {
620   assert(SPAdj == 0 && "Unexpected");
621 
622   // Get the instruction.
623   MachineInstr &MI = *II;
624   // Get the instruction's basic block.
625   MachineBasicBlock &MBB = *MI.getParent();
626   // Get the basic block's function.
627   MachineFunction &MF = *MBB.getParent();
628   // Get the frame info.
629   MachineFrameInfo *MFI = MF.getFrameInfo();
630 
631   // Find out which operand is the frame index.
632   unsigned FIOperandNo = 0;
633   while (!MI.getOperand(FIOperandNo).isFI()) {
634     ++FIOperandNo;
635     assert(FIOperandNo != MI.getNumOperands() &&
636            "Instr doesn't have FrameIndex operand!");
637   }
638   // Take into account whether it's an add or mem instruction
639   unsigned OffsetOperandNo = (FIOperandNo == 2) ? 1 : 2;
640   if (MI.getOpcode() == TargetInstrInfo::INLINEASM)
641     OffsetOperandNo = FIOperandNo-1;
642 
643   // Get the frame index.
644   int FrameIndex = MI.getOperand(FIOperandNo).getIndex();
645 
646   // Get the frame pointer save index.  Users of this index are primarily
647   // DYNALLOC instructions.
648   PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
649   int FPSI = FI->getFramePointerSaveIndex();
650   // Get the instruction opcode.
651   unsigned OpC = MI.getOpcode();
652 
653   // Special case for dynamic alloca.
654   if (FPSI && FrameIndex == FPSI &&
655       (OpC == PPC::DYNALLOC || OpC == PPC::DYNALLOC8)) {
656     lowerDynamicAlloc(II, SPAdj, RS);
657     return;
658   }
659 
660   // Special case for pseudo-op SPILL_CR.
661   if (EnableRegisterScavenging) // FIXME (64-bit): Enable by default.
662     if (OpC == PPC::SPILL_CR) {
663       lowerCRSpilling(II, FrameIndex, SPAdj, RS);
664       return;
665     }
666 
667   // Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
668   MI.getOperand(FIOperandNo).ChangeToRegister(hasFP(MF) ? PPC::R31 : PPC::R1,
669                                               false);
670 
671   // Figure out if the offset in the instruction is shifted right two bits. This
672   // is true for instructions like "STD", which the machine implicitly adds two
673   // low zeros to.
674   bool isIXAddr = false;
675   switch (OpC) {
676   case PPC::LWA:
677   case PPC::LD:
678   case PPC::STD:
679   case PPC::STD_32:
680     isIXAddr = true;
681     break;
682   }
683 
684   // Now add the frame object offset to the offset from r1.
685   int Offset = MFI->getObjectOffset(FrameIndex);
686   if (!isIXAddr)
687     Offset += MI.getOperand(OffsetOperandNo).getImm();
688   else
689     Offset += MI.getOperand(OffsetOperandNo).getImm() << 2;
690 
691   // If we're not using a Frame Pointer that has been set to the value of the
692   // SP before having the stack size subtracted from it, then add the stack size
693   // to Offset to get the correct offset.
694   Offset += MFI->getStackSize();
695 
696   // If we can, encode the offset directly into the instruction.  If this is a
697   // normal PPC "ri" instruction, any 16-bit value can be safely encoded.  If
698   // this is a PPC64 "ix" instruction, only a 16-bit value with the low two bits
699   // clear can be encoded.  This is extremely uncommon, because normally you
700   // only "std" to a stack slot that is at least 4-byte aligned, but it can
701   // happen in invalid code.
702   if (isInt16(Offset) && (!isIXAddr || (Offset & 3) == 0)) {
703     if (isIXAddr)
704       Offset >>= 2;    // The actual encoded value has the low two bits zero.
705     MI.getOperand(OffsetOperandNo).ChangeToImmediate(Offset);
706     return;
707   }
708 
709   // The offset doesn't fit into a single register, scavenge one to build the
710   // offset in.
711   // FIXME: figure out what SPAdj is doing here.
712 
713   // FIXME (64-bit): Use "findScratchRegister".
714   unsigned SReg;
715   if (EnableRegisterScavenging)
716     SReg = findScratchRegister(II, RS, &PPC::GPRCRegClass, SPAdj);
717   else
718     SReg = PPC::R0;
719 
720   // Insert a set of rA with the full offset value before the ld, st, or add
721   BuildMI(MBB, II, TII.get(PPC::LIS), SReg)
722     .addImm(Offset >> 16);
723   BuildMI(MBB, II, TII.get(PPC::ORI), SReg)
724     .addReg(SReg, false, false, true)
725     .addImm(Offset);
726 
727   // Convert into indexed form of the instruction:
728   //
729   //   sth 0:rA, 1:imm 2:(rB) ==> sthx 0:rA, 2:rB, 1:r0
730   //   addi 0:rA 1:rB, 2, imm ==> add 0:rA, 1:rB, 2:r0
731   unsigned OperandBase;
732 
733   if (OpC != TargetInstrInfo::INLINEASM) {
734     assert(ImmToIdxMap.count(OpC) &&
735            "No indexed form of load or store available!");
736     unsigned NewOpcode = ImmToIdxMap.find(OpC)->second;
737     MI.setDesc(TII.get(NewOpcode));
738     OperandBase = 1;
739   } else {
740     OperandBase = OffsetOperandNo;
741   }
742 
743   unsigned StackReg = MI.getOperand(FIOperandNo).getReg();
744   MI.getOperand(OperandBase).ChangeToRegister(StackReg, false);
745   MI.getOperand(OperandBase + 1).ChangeToRegister(SReg, false);
746 }
747 
748 /// VRRegNo - Map from a numbered VR register to its enum value.
749 ///
750 static const unsigned short VRRegNo[] = {
751  PPC::V0 , PPC::V1 , PPC::V2 , PPC::V3 , PPC::V4 , PPC::V5 , PPC::V6 , PPC::V7 ,
752  PPC::V8 , PPC::V9 , PPC::V10, PPC::V11, PPC::V12, PPC::V13, PPC::V14, PPC::V15,
753  PPC::V16, PPC::V17, PPC::V18, PPC::V19, PPC::V20, PPC::V21, PPC::V22, PPC::V23,
754  PPC::V24, PPC::V25, PPC::V26, PPC::V27, PPC::V28, PPC::V29, PPC::V30, PPC::V31
755 };
756 
757 /// RemoveVRSaveCode - We have found that this function does not need any code
758 /// to manipulate the VRSAVE register, even though it uses vector registers.
759 /// This can happen when the only registers used are known to be live in or out
760 /// of the function.  Remove all of the VRSAVE related code from the function.
761 static void RemoveVRSaveCode(MachineInstr *MI) {
762   MachineBasicBlock *Entry = MI->getParent();
763   MachineFunction *MF = Entry->getParent();
764 
765   // We know that the MTVRSAVE instruction immediately follows MI.  Remove it.
766   MachineBasicBlock::iterator MBBI = MI;
767   ++MBBI;
768   assert(MBBI != Entry->end() && MBBI->getOpcode() == PPC::MTVRSAVE);
769   MBBI->eraseFromParent();
770 
771   bool RemovedAllMTVRSAVEs = true;
772   // See if we can find and remove the MTVRSAVE instruction from all of the
773   // epilog blocks.
774   for (MachineFunction::iterator I = MF->begin(), E = MF->end(); I != E; ++I) {
775     // If last instruction is a return instruction, add an epilogue
776     if (!I->empty() && I->back().getDesc().isReturn()) {
777       bool FoundIt = false;
778       for (MBBI = I->end(); MBBI != I->begin(); ) {
779         --MBBI;
780         if (MBBI->getOpcode() == PPC::MTVRSAVE) {
781           MBBI->eraseFromParent();  // remove it.
782           FoundIt = true;
783           break;
784         }
785       }
786       RemovedAllMTVRSAVEs &= FoundIt;
787     }
788   }
789 
790   // If we found and removed all MTVRSAVE instructions, remove the read of
791   // VRSAVE as well.
792   if (RemovedAllMTVRSAVEs) {
793     MBBI = MI;
794     assert(MBBI != Entry->begin() && "UPDATE_VRSAVE is first instr in block?");
795     --MBBI;
796     assert(MBBI->getOpcode() == PPC::MFVRSAVE && "VRSAVE instrs wandered?");
797     MBBI->eraseFromParent();
798   }
799 
800   // Finally, nuke the UPDATE_VRSAVE.
801   MI->eraseFromParent();
802 }
803 
804 // HandleVRSaveUpdate - MI is the UPDATE_VRSAVE instruction introduced by the
805 // instruction selector.  Based on the vector registers that have been used,
806 // transform this into the appropriate ORI instruction.
807 static void HandleVRSaveUpdate(MachineInstr *MI, const TargetInstrInfo &TII) {
808   MachineFunction *MF = MI->getParent()->getParent();
809 
810   unsigned UsedRegMask = 0;
811   for (unsigned i = 0; i != 32; ++i)
812     if (MF->getRegInfo().isPhysRegUsed(VRRegNo[i]))
813       UsedRegMask |= 1 << (31-i);
814 
815   // Live in and live out values already must be in the mask, so don't bother
816   // marking them.
817   for (MachineRegisterInfo::livein_iterator
818        I = MF->getRegInfo().livein_begin(),
819        E = MF->getRegInfo().livein_end(); I != E; ++I) {
820     unsigned RegNo = PPCRegisterInfo::getRegisterNumbering(I->first);
821     if (VRRegNo[RegNo] == I->first)        // If this really is a vector reg.
822       UsedRegMask &= ~(1 << (31-RegNo));   // Doesn't need to be marked.
823   }
824   for (MachineRegisterInfo::liveout_iterator
825        I = MF->getRegInfo().liveout_begin(),
826        E = MF->getRegInfo().liveout_end(); I != E; ++I) {
827     unsigned RegNo = PPCRegisterInfo::getRegisterNumbering(*I);
828     if (VRRegNo[RegNo] == *I)              // If this really is a vector reg.
829       UsedRegMask &= ~(1 << (31-RegNo));   // Doesn't need to be marked.
830   }
831 
832   // If no registers are used, turn this into a copy.
833   if (UsedRegMask == 0) {
834     // Remove all VRSAVE code.
835     RemoveVRSaveCode(MI);
836     return;
837   }
838 
839   unsigned SrcReg = MI->getOperand(1).getReg();
840   unsigned DstReg = MI->getOperand(0).getReg();
841 
842   if ((UsedRegMask & 0xFFFF) == UsedRegMask) {
843     if (DstReg != SrcReg)
844       BuildMI(*MI->getParent(), MI, TII.get(PPC::ORI), DstReg)
845         .addReg(SrcReg)
846         .addImm(UsedRegMask);
847     else
848       BuildMI(*MI->getParent(), MI, TII.get(PPC::ORI), DstReg)
849         .addReg(SrcReg, false, false, true)
850         .addImm(UsedRegMask);
851   } else if ((UsedRegMask & 0xFFFF0000) == UsedRegMask) {
852     if (DstReg != SrcReg)
853       BuildMI(*MI->getParent(), MI, TII.get(PPC::ORIS), DstReg)
854         .addReg(SrcReg)
855         .addImm(UsedRegMask >> 16);
856     else
857       BuildMI(*MI->getParent(), MI, TII.get(PPC::ORIS), DstReg)
858         .addReg(SrcReg, false, false, true)
859         .addImm(UsedRegMask >> 16);
860   } else {
861     if (DstReg != SrcReg)
862       BuildMI(*MI->getParent(), MI, TII.get(PPC::ORIS), DstReg)
863         .addReg(SrcReg)
864         .addImm(UsedRegMask >> 16);
865     else
866       BuildMI(*MI->getParent(), MI, TII.get(PPC::ORIS), DstReg)
867         .addReg(SrcReg, false, false, true)
868         .addImm(UsedRegMask >> 16);
869 
870     BuildMI(*MI->getParent(), MI, TII.get(PPC::ORI), DstReg)
871       .addReg(DstReg, false, false, true)
872       .addImm(UsedRegMask & 0xFFFF);
873   }
874 
875   // Remove the old UPDATE_VRSAVE instruction.
876   MI->eraseFromParent();
877 }
878 
879 /// determineFrameLayout - Determine the size of the frame and maximum call
880 /// frame size.
881 void PPCRegisterInfo::determineFrameLayout(MachineFunction &MF) const {
882   MachineFrameInfo *MFI = MF.getFrameInfo();
883 
884   // Get the number of bytes to allocate from the FrameInfo
885   unsigned FrameSize = MFI->getStackSize();
886 
887   // Get the alignments provided by the target, and the maximum alignment
888   // (if any) of the fixed frame objects.
889   unsigned MaxAlign = MFI->getMaxAlignment();
890   unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
891   unsigned AlignMask = TargetAlign - 1;  //
892 
893   // If we are a leaf function, and use up to 224 bytes of stack space,
894   // don't have a frame pointer, calls, or dynamic alloca then we do not need
895   // to adjust the stack pointer (we fit in the Red Zone).
896   if (!DisableRedZone &&
897       FrameSize <= 224 &&                          // Fits in red zone.
898       !MFI->hasVarSizedObjects() &&                // No dynamic alloca.
899       !MFI->hasCalls() &&                          // No calls.
900       (!ALIGN_STACK || MaxAlign <= TargetAlign)) { // No special alignment.
901     // No need for frame
902     MFI->setStackSize(0);
903     return;
904   }
905 
906   // Get the maximum call frame size of all the calls.
907   unsigned maxCallFrameSize = MFI->getMaxCallFrameSize();
908 
909   // Maximum call frame needs to be at least big enough for linkage and 8 args.
910   unsigned minCallFrameSize =
911     PPCFrameInfo::getMinCallFrameSize(Subtarget.isPPC64(),
912                                       Subtarget.isMachoABI());
913   maxCallFrameSize = std::max(maxCallFrameSize, minCallFrameSize);
914 
915   // If we have dynamic alloca then maxCallFrameSize needs to be aligned so
916   // that allocations will be aligned.
917   if (MFI->hasVarSizedObjects())
918     maxCallFrameSize = (maxCallFrameSize + AlignMask) & ~AlignMask;
919 
920   // Update maximum call frame size.
921   MFI->setMaxCallFrameSize(maxCallFrameSize);
922 
923   // Include call frame size in total.
924   FrameSize += maxCallFrameSize;
925 
926   // Make sure the frame is aligned.
927   FrameSize = (FrameSize + AlignMask) & ~AlignMask;
928 
929   // Update frame info.
930   MFI->setStackSize(FrameSize);
931 }
932 
933 void
934 PPCRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
935                                                       RegScavenger *RS) const {
936   //  Save and clear the LR state.
937   PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
938   unsigned LR = getRARegister();
939   FI->setMustSaveLR(MustSaveLR(MF, LR));
940   MF.getRegInfo().setPhysRegUnused(LR);
941 
942   //  Save R31 if necessary
943   int FPSI = FI->getFramePointerSaveIndex();
944   bool IsPPC64 = Subtarget.isPPC64();
945   bool IsELF32_ABI = Subtarget.isELF32_ABI();
946   bool IsMachoABI  = Subtarget.isMachoABI();
947   MachineFrameInfo *MFI = MF.getFrameInfo();
948 
949   // If the frame pointer save index hasn't been defined yet.
950   if (!FPSI && (NoFramePointerElim || MFI->hasVarSizedObjects()) &&
951       IsELF32_ABI) {
952     // Find out what the fix offset of the frame pointer save area.
953     int FPOffset = PPCFrameInfo::getFramePointerSaveOffset(IsPPC64,
954                                                            IsMachoABI);
955     // Allocate the frame index for frame pointer save area.
956     FPSI = MF.getFrameInfo()->CreateFixedObject(IsPPC64? 8 : 4, FPOffset);
957     // Save the result.
958     FI->setFramePointerSaveIndex(FPSI);
959   }
960 
961   // Reserve stack space to move the linkage area to in case of a tail call.
962   int TCSPDelta = 0;
963   if (PerformTailCallOpt && (TCSPDelta=FI->getTailCallSPDelta()) < 0) {
964     int AddFPOffsetAmount = IsELF32_ABI ? -4 : 0;
965     MF.getFrameInfo()->CreateFixedObject( -1 * TCSPDelta,
966                                           AddFPOffsetAmount + TCSPDelta);
967   }
968   // Reserve a slot closest to SP or frame pointer if we have a dynalloc or
969   // a large stack, which will require scavenging a register to materialize a
970   // large offset.
971   // FIXME: this doesn't actually check stack size, so is a bit pessimistic
972   // FIXME: doesn't detect whether or not we need to spill vXX, which requires
973   //        r0 for now.
974 
975   if (EnableRegisterScavenging) // FIXME (64-bit): Enable.
976     if (needsFP(MF) || spillsCR(MF)) {
977       const TargetRegisterClass *GPRC = &PPC::GPRCRegClass;
978       const TargetRegisterClass *G8RC = &PPC::G8RCRegClass;
979       const TargetRegisterClass *RC = IsPPC64 ? G8RC : GPRC;
980       RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
981                                                          RC->getAlignment()));
982     }
983 }
984 
985 void
986 PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {
987   MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
988   MachineBasicBlock::iterator MBBI = MBB.begin();
989   MachineFrameInfo *MFI = MF.getFrameInfo();
990   MachineModuleInfo *MMI = MFI->getMachineModuleInfo();
991   bool needsFrameMoves = (MMI && MMI->hasDebugInfo()) ||
992        !MF.getFunction()->doesNotThrow() ||
993        UnwindTablesMandatory;
994 
995   // Prepare for frame info.
996   unsigned FrameLabelId = 0;
997 
998   // Scan the prolog, looking for an UPDATE_VRSAVE instruction.  If we find it,
999   // process it.
1000   for (unsigned i = 0; MBBI != MBB.end(); ++i, ++MBBI) {
1001     if (MBBI->getOpcode() == PPC::UPDATE_VRSAVE) {
1002       HandleVRSaveUpdate(MBBI, TII);
1003       break;
1004     }
1005   }
1006 
1007   // Move MBBI back to the beginning of the function.
1008   MBBI = MBB.begin();
1009 
1010   // Work out frame sizes.
1011   determineFrameLayout(MF);
1012   unsigned FrameSize = MFI->getStackSize();
1013 
1014   int NegFrameSize = -FrameSize;
1015 
1016   // Get processor type.
1017   bool IsPPC64 = Subtarget.isPPC64();
1018   // Get operating system
1019   bool IsMachoABI = Subtarget.isMachoABI();
1020   // Check if the link register (LR) must be saved.
1021   PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
1022   bool MustSaveLR = FI->mustSaveLR();
1023   // Do we have a frame pointer for this function?
1024   bool HasFP = hasFP(MF) && FrameSize;
1025 
1026   int LROffset = PPCFrameInfo::getReturnSaveOffset(IsPPC64, IsMachoABI);
1027   int FPOffset = PPCFrameInfo::getFramePointerSaveOffset(IsPPC64, IsMachoABI);
1028 
1029   if (IsPPC64) {
1030     if (MustSaveLR)
1031       BuildMI(MBB, MBBI, TII.get(PPC::MFLR8), PPC::X0);
1032 
1033     if (HasFP)
1034       BuildMI(MBB, MBBI, TII.get(PPC::STD))
1035         .addReg(PPC::X31)
1036         .addImm(FPOffset/4)
1037         .addReg(PPC::X1);
1038 
1039     if (MustSaveLR)
1040       BuildMI(MBB, MBBI, TII.get(PPC::STD))
1041         .addReg(PPC::X0)
1042         .addImm(LROffset / 4)
1043         .addReg(PPC::X1);
1044   } else {
1045     if (MustSaveLR)
1046       BuildMI(MBB, MBBI, TII.get(PPC::MFLR), PPC::R0);
1047 
1048     if (HasFP)
1049       BuildMI(MBB, MBBI, TII.get(PPC::STW))
1050         .addReg(PPC::R31)
1051         .addImm(FPOffset)
1052         .addReg(PPC::R1);
1053 
1054     if (MustSaveLR)
1055       BuildMI(MBB, MBBI, TII.get(PPC::STW))
1056         .addReg(PPC::R0)
1057         .addImm(LROffset)
1058         .addReg(PPC::R1);
1059   }
1060 
1061   // Skip if a leaf routine.
1062   if (!FrameSize) return;
1063 
1064   // Get stack alignments.
1065   unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
1066   unsigned MaxAlign = MFI->getMaxAlignment();
1067 
1068   if (needsFrameMoves) {
1069     // Mark effective beginning of when frame pointer becomes valid.
1070     FrameLabelId = MMI->NextLabelID();
1071     BuildMI(MBB, MBBI, TII.get(PPC::DBG_LABEL)).addImm(FrameLabelId);
1072   }
1073 
1074   // Adjust stack pointer: r1 += NegFrameSize.
1075   // If there is a preferred stack alignment, align R1 now
1076   if (!IsPPC64) {
1077     // PPC32.
1078     if (ALIGN_STACK && MaxAlign > TargetAlign) {
1079       assert(isPowerOf2_32(MaxAlign)&&isInt16(MaxAlign)&&"Invalid alignment!");
1080       assert(isInt16(NegFrameSize) && "Unhandled stack size and alignment!");
1081 
1082       BuildMI(MBB, MBBI, TII.get(PPC::RLWINM), PPC::R0)
1083         .addReg(PPC::R1)
1084         .addImm(0)
1085         .addImm(32 - Log2_32(MaxAlign))
1086         .addImm(31);
1087       BuildMI(MBB, MBBI, TII.get(PPC::SUBFIC) ,PPC::R0)
1088         .addReg(PPC::R0, false, false, true)
1089         .addImm(NegFrameSize);
1090       BuildMI(MBB, MBBI, TII.get(PPC::STWUX))
1091         .addReg(PPC::R1)
1092         .addReg(PPC::R1)
1093         .addReg(PPC::R0);
1094     } else if (isInt16(NegFrameSize)) {
1095       BuildMI(MBB, MBBI, TII.get(PPC::STWU), PPC::R1)
1096         .addReg(PPC::R1)
1097         .addImm(NegFrameSize)
1098         .addReg(PPC::R1);
1099     } else {
1100       BuildMI(MBB, MBBI, TII.get(PPC::LIS), PPC::R0)
1101         .addImm(NegFrameSize >> 16);
1102       BuildMI(MBB, MBBI, TII.get(PPC::ORI), PPC::R0)
1103         .addReg(PPC::R0, false, false, true)
1104         .addImm(NegFrameSize & 0xFFFF);
1105       BuildMI(MBB, MBBI, TII.get(PPC::STWUX))
1106         .addReg(PPC::R1)
1107         .addReg(PPC::R1)
1108         .addReg(PPC::R0);
1109     }
1110   } else {    // PPC64.
1111     if (ALIGN_STACK && MaxAlign > TargetAlign) {
1112       assert(isPowerOf2_32(MaxAlign)&&isInt16(MaxAlign)&&"Invalid alignment!");
1113       assert(isInt16(NegFrameSize) && "Unhandled stack size and alignment!");
1114 
1115       BuildMI(MBB, MBBI, TII.get(PPC::RLDICL), PPC::X0)
1116         .addReg(PPC::X1)
1117         .addImm(0)
1118         .addImm(64 - Log2_32(MaxAlign));
1119       BuildMI(MBB, MBBI, TII.get(PPC::SUBFIC8), PPC::X0)
1120         .addReg(PPC::X0)
1121         .addImm(NegFrameSize);
1122       BuildMI(MBB, MBBI, TII.get(PPC::STDUX))
1123         .addReg(PPC::X1)
1124         .addReg(PPC::X1)
1125         .addReg(PPC::X0);
1126     } else if (isInt16(NegFrameSize)) {
1127       BuildMI(MBB, MBBI, TII.get(PPC::STDU), PPC::X1)
1128         .addReg(PPC::X1)
1129         .addImm(NegFrameSize / 4)
1130         .addReg(PPC::X1);
1131     } else {
1132       BuildMI(MBB, MBBI, TII.get(PPC::LIS8), PPC::X0)
1133         .addImm(NegFrameSize >> 16);
1134       BuildMI(MBB, MBBI, TII.get(PPC::ORI8), PPC::X0)
1135         .addReg(PPC::X0, false, false, true)
1136         .addImm(NegFrameSize & 0xFFFF);
1137       BuildMI(MBB, MBBI, TII.get(PPC::STDUX))
1138         .addReg(PPC::X1)
1139         .addReg(PPC::X1)
1140         .addReg(PPC::X0);
1141     }
1142   }
1143 
1144   if (needsFrameMoves) {
1145     std::vector<MachineMove> &Moves = MMI->getFrameMoves();
1146 
1147     if (NegFrameSize) {
1148       // Show update of SP.
1149       MachineLocation SPDst(MachineLocation::VirtualFP);
1150       MachineLocation SPSrc(MachineLocation::VirtualFP, NegFrameSize);
1151       Moves.push_back(MachineMove(FrameLabelId, SPDst, SPSrc));
1152     } else {
1153       MachineLocation SP(IsPPC64 ? PPC::X31 : PPC::R31);
1154       Moves.push_back(MachineMove(FrameLabelId, SP, SP));
1155     }
1156 
1157     if (HasFP) {
1158       MachineLocation FPDst(MachineLocation::VirtualFP, FPOffset);
1159       MachineLocation FPSrc(IsPPC64 ? PPC::X31 : PPC::R31);
1160       Moves.push_back(MachineMove(FrameLabelId, FPDst, FPSrc));
1161     }
1162 
1163     // Add callee saved registers to move list.
1164     const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
1165     for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
1166       int Offset = MFI->getObjectOffset(CSI[I].getFrameIdx());
1167       unsigned Reg = CSI[I].getReg();
1168       if (Reg == PPC::LR || Reg == PPC::LR8 || Reg == PPC::RM) continue;
1169       MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
1170       MachineLocation CSSrc(Reg);
1171       Moves.push_back(MachineMove(FrameLabelId, CSDst, CSSrc));
1172     }
1173 
1174     MachineLocation LRDst(MachineLocation::VirtualFP, LROffset);
1175     MachineLocation LRSrc(IsPPC64 ? PPC::LR8 : PPC::LR);
1176     Moves.push_back(MachineMove(FrameLabelId, LRDst, LRSrc));
1177 
1178     // Mark effective beginning of when frame pointer is ready.
1179     unsigned ReadyLabelId = MMI->NextLabelID();
1180     BuildMI(MBB, MBBI, TII.get(PPC::DBG_LABEL)).addImm(ReadyLabelId);
1181 
1182     MachineLocation FPDst(HasFP ? (IsPPC64 ? PPC::X31 : PPC::R31) :
1183                                   (IsPPC64 ? PPC::X1 : PPC::R1));
1184     MachineLocation FPSrc(MachineLocation::VirtualFP);
1185     Moves.push_back(MachineMove(ReadyLabelId, FPDst, FPSrc));
1186   }
1187 
1188   // If there is a frame pointer, copy R1 into R31
1189   if (HasFP) {
1190     if (!IsPPC64) {
1191       BuildMI(MBB, MBBI, TII.get(PPC::OR), PPC::R31)
1192         .addReg(PPC::R1)
1193         .addReg(PPC::R1);
1194     } else {
1195       BuildMI(MBB, MBBI, TII.get(PPC::OR8), PPC::X31)
1196         .addReg(PPC::X1)
1197         .addReg(PPC::X1);
1198     }
1199   }
1200 }
1201 
1202 void PPCRegisterInfo::emitEpilogue(MachineFunction &MF,
1203                                    MachineBasicBlock &MBB) const {
1204   MachineBasicBlock::iterator MBBI = prior(MBB.end());
1205   unsigned RetOpcode = MBBI->getOpcode();
1206 
1207   assert( (RetOpcode == PPC::BLR ||
1208            RetOpcode == PPC::TCRETURNri ||
1209            RetOpcode == PPC::TCRETURNdi ||
1210            RetOpcode == PPC::TCRETURNai ||
1211            RetOpcode == PPC::TCRETURNri8 ||
1212            RetOpcode == PPC::TCRETURNdi8 ||
1213            RetOpcode == PPC::TCRETURNai8) &&
1214          "Can only insert epilog into returning blocks");
1215 
1216   // Get alignment info so we know how to restore r1
1217   const MachineFrameInfo *MFI = MF.getFrameInfo();
1218   unsigned TargetAlign = MF.getTarget().getFrameInfo()->getStackAlignment();
1219   unsigned MaxAlign = MFI->getMaxAlignment();
1220 
1221   // Get the number of bytes allocated from the FrameInfo.
1222   int FrameSize = MFI->getStackSize();
1223 
1224   // Get processor type.
1225   bool IsPPC64 = Subtarget.isPPC64();
1226   // Get operating system
1227   bool IsMachoABI = Subtarget.isMachoABI();
1228   // Check if the link register (LR) has been saved.
1229   PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
1230   bool MustSaveLR = FI->mustSaveLR();
1231   // Do we have a frame pointer for this function?
1232   bool HasFP = hasFP(MF) && FrameSize;
1233 
1234   int LROffset = PPCFrameInfo::getReturnSaveOffset(IsPPC64, IsMachoABI);
1235   int FPOffset = PPCFrameInfo::getFramePointerSaveOffset(IsPPC64, IsMachoABI);
1236 
1237   bool UsesTCRet =  RetOpcode == PPC::TCRETURNri ||
1238     RetOpcode == PPC::TCRETURNdi ||
1239     RetOpcode == PPC::TCRETURNai ||
1240     RetOpcode == PPC::TCRETURNri8 ||
1241     RetOpcode == PPC::TCRETURNdi8 ||
1242     RetOpcode == PPC::TCRETURNai8;
1243 
1244   if (UsesTCRet) {
1245     int MaxTCRetDelta = FI->getTailCallSPDelta();
1246     MachineOperand &StackAdjust = MBBI->getOperand(1);
1247     assert(StackAdjust.isImm() && "Expecting immediate value.");
1248     // Adjust stack pointer.
1249     int StackAdj = StackAdjust.getImm();
1250     int Delta = StackAdj - MaxTCRetDelta;
1251     assert((Delta >= 0) && "Delta must be positive");
1252     if (MaxTCRetDelta>0)
1253       FrameSize += (StackAdj +Delta);
1254     else
1255       FrameSize += StackAdj;
1256   }
1257 
1258   if (FrameSize) {
1259     // The loaded (or persistent) stack pointer value is offset by the 'stwu'
1260     // on entry to the function.  Add this offset back now.
1261     if (!IsPPC64) {
1262       // If this function contained a fastcc call and PerformTailCallOpt is
1263       // enabled (=> hasFastCall()==true) the fastcc call might contain a tail
1264       // call which invalidates the stack pointer value in SP(0). So we use the
1265       // value of R31 in this case.
1266       if (FI->hasFastCall() && isInt16(FrameSize)) {
1267         assert(hasFP(MF) && "Expecting a valid the frame pointer.");
1268         BuildMI(MBB, MBBI, TII.get(PPC::ADDI), PPC::R1)
1269           .addReg(PPC::R31).addImm(FrameSize);
1270       } else if(FI->hasFastCall()) {
1271         BuildMI(MBB, MBBI, TII.get(PPC::LIS), PPC::R0)
1272           .addImm(FrameSize >> 16);
1273         BuildMI(MBB, MBBI, TII.get(PPC::ORI), PPC::R0)
1274           .addReg(PPC::R0, false, false, true)
1275           .addImm(FrameSize & 0xFFFF);
1276         BuildMI(MBB, MBBI, TII.get(PPC::ADD4))
1277           .addReg(PPC::R1)
1278           .addReg(PPC::R31)
1279           .addReg(PPC::R0);
1280       } else if (isInt16(FrameSize) &&
1281                  (!ALIGN_STACK || TargetAlign >= MaxAlign) &&
1282                  !MFI->hasVarSizedObjects()) {
1283         BuildMI(MBB, MBBI, TII.get(PPC::ADDI), PPC::R1)
1284           .addReg(PPC::R1).addImm(FrameSize);
1285       } else {
1286         BuildMI(MBB, MBBI, TII.get(PPC::LWZ),PPC::R1).addImm(0).addReg(PPC::R1);
1287       }
1288     } else {
1289       if (FI->hasFastCall() && isInt16(FrameSize)) {
1290         assert(hasFP(MF) && "Expecting a valid the frame pointer.");
1291         BuildMI(MBB, MBBI, TII.get(PPC::ADDI8), PPC::X1)
1292           .addReg(PPC::X31).addImm(FrameSize);
1293       } else if(FI->hasFastCall()) {
1294         BuildMI(MBB, MBBI, TII.get(PPC::LIS8), PPC::X0)
1295           .addImm(FrameSize >> 16);
1296         BuildMI(MBB, MBBI, TII.get(PPC::ORI8), PPC::X0)
1297           .addReg(PPC::X0, false, false, true)
1298           .addImm(FrameSize & 0xFFFF);
1299         BuildMI(MBB, MBBI, TII.get(PPC::ADD8))
1300           .addReg(PPC::X1)
1301           .addReg(PPC::X31)
1302           .addReg(PPC::X0);
1303       } else if (isInt16(FrameSize) && TargetAlign >= MaxAlign &&
1304             !MFI->hasVarSizedObjects()) {
1305         BuildMI(MBB, MBBI, TII.get(PPC::ADDI8), PPC::X1)
1306            .addReg(PPC::X1).addImm(FrameSize);
1307       } else {
1308         BuildMI(MBB, MBBI, TII.get(PPC::LD), PPC::X1).addImm(0).addReg(PPC::X1);
1309       }
1310     }
1311   }
1312 
1313   if (IsPPC64) {
1314     if (MustSaveLR)
1315       BuildMI(MBB, MBBI, TII.get(PPC::LD), PPC::X0)
1316         .addImm(LROffset/4).addReg(PPC::X1);
1317 
1318     if (HasFP)
1319       BuildMI(MBB, MBBI, TII.get(PPC::LD), PPC::X31)
1320         .addImm(FPOffset/4).addReg(PPC::X1);
1321 
1322     if (MustSaveLR)
1323       BuildMI(MBB, MBBI, TII.get(PPC::MTLR8)).addReg(PPC::X0);
1324   } else {
1325     if (MustSaveLR)
1326       BuildMI(MBB, MBBI, TII.get(PPC::LWZ), PPC::R0)
1327           .addImm(LROffset).addReg(PPC::R1);
1328 
1329     if (HasFP)
1330       BuildMI(MBB, MBBI, TII.get(PPC::LWZ), PPC::R31)
1331           .addImm(FPOffset).addReg(PPC::R1);
1332 
1333     if (MustSaveLR)
1334       BuildMI(MBB, MBBI, TII.get(PPC::MTLR)).addReg(PPC::R0);
1335   }
1336 
1337   // Callee pop calling convention. Pop parameter/linkage area. Used for tail
1338   // call optimization
1339   if (PerformTailCallOpt && RetOpcode == PPC::BLR &&
1340       MF.getFunction()->getCallingConv() == CallingConv::Fast) {
1341      PPCFunctionInfo *FI = MF.getInfo<PPCFunctionInfo>();
1342      unsigned CallerAllocatedAmt = FI->getMinReservedArea();
1343      unsigned StackReg = IsPPC64 ? PPC::X1 : PPC::R1;
1344      unsigned FPReg = IsPPC64 ? PPC::X31 : PPC::R31;
1345      unsigned TmpReg = IsPPC64 ? PPC::X0 : PPC::R0;
1346      unsigned ADDIInstr = IsPPC64 ? PPC::ADDI8 : PPC::ADDI;
1347      unsigned ADDInstr = IsPPC64 ? PPC::ADD8 : PPC::ADD4;
1348      unsigned LISInstr = IsPPC64 ? PPC::LIS8 : PPC::LIS;
1349      unsigned ORIInstr = IsPPC64 ? PPC::ORI8 : PPC::ORI;
1350 
1351      if (CallerAllocatedAmt && isInt16(CallerAllocatedAmt)) {
1352        BuildMI(MBB, MBBI, TII.get(ADDIInstr), StackReg)
1353          .addReg(StackReg).addImm(CallerAllocatedAmt);
1354      } else {
1355         BuildMI(MBB, MBBI, TII.get(LISInstr), TmpReg)
1356           .addImm(CallerAllocatedAmt >> 16);
1357         BuildMI(MBB, MBBI, TII.get(ORIInstr), TmpReg)
1358           .addReg(TmpReg, false, false, true)
1359           .addImm(CallerAllocatedAmt & 0xFFFF);
1360         BuildMI(MBB, MBBI, TII.get(ADDInstr))
1361           .addReg(StackReg)
1362           .addReg(FPReg)
1363           .addReg(TmpReg);
1364      }
1365   } else if (RetOpcode == PPC::TCRETURNdi) {
1366     MBBI = prior(MBB.end());
1367     MachineOperand &JumpTarget = MBBI->getOperand(0);
1368     BuildMI(MBB, MBBI, TII.get(PPC::TAILB)).
1369       addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset());
1370   } else if (RetOpcode == PPC::TCRETURNri) {
1371     MBBI = prior(MBB.end());
1372     MachineOperand &JumpTarget = MBBI->getOperand(0);
1373     assert(JumpTarget.isReg() && "Expecting register operand.");
1374     BuildMI(MBB, MBBI, TII.get(PPC::TAILBCTR));
1375   } else if (RetOpcode == PPC::TCRETURNai) {
1376     MBBI = prior(MBB.end());
1377     MachineOperand &JumpTarget = MBBI->getOperand(0);
1378     BuildMI(MBB, MBBI, TII.get(PPC::TAILBA)).addImm(JumpTarget.getImm());
1379   } else if (RetOpcode == PPC::TCRETURNdi8) {
1380     MBBI = prior(MBB.end());
1381     MachineOperand &JumpTarget = MBBI->getOperand(0);
1382     BuildMI(MBB, MBBI, TII.get(PPC::TAILB8)).
1383       addGlobalAddress(JumpTarget.getGlobal(), JumpTarget.getOffset());
1384   } else if (RetOpcode == PPC::TCRETURNri8) {
1385     MBBI = prior(MBB.end());
1386     MachineOperand &JumpTarget = MBBI->getOperand(0);
1387     assert(JumpTarget.isReg() && "Expecting register operand.");
1388     BuildMI(MBB, MBBI, TII.get(PPC::TAILBCTR8));
1389   } else if (RetOpcode == PPC::TCRETURNai8) {
1390     MBBI = prior(MBB.end());
1391     MachineOperand &JumpTarget = MBBI->getOperand(0);
1392     BuildMI(MBB, MBBI, TII.get(PPC::TAILBA8)).addImm(JumpTarget.getImm());
1393   }
1394 }
1395 
1396 unsigned PPCRegisterInfo::getRARegister() const {
1397   return !Subtarget.isPPC64() ? PPC::LR : PPC::LR8;
1398 }
1399 
1400 unsigned PPCRegisterInfo::getFrameRegister(MachineFunction &MF) const {
1401   if (!Subtarget.isPPC64())
1402     return hasFP(MF) ? PPC::R31 : PPC::R1;
1403   else
1404     return hasFP(MF) ? PPC::X31 : PPC::X1;
1405 }
1406 
1407 void PPCRegisterInfo::getInitialFrameState(std::vector<MachineMove> &Moves)
1408                                                                          const {
1409   // Initial state of the frame pointer is R1.
1410   MachineLocation Dst(MachineLocation::VirtualFP);
1411   MachineLocation Src(PPC::R1, 0);
1412   Moves.push_back(MachineMove(0, Dst, Src));
1413 }
1414 
1415 unsigned PPCRegisterInfo::getEHExceptionRegister() const {
1416   return !Subtarget.isPPC64() ? PPC::R3 : PPC::X3;
1417 }
1418 
1419 unsigned PPCRegisterInfo::getEHHandlerRegister() const {
1420   return !Subtarget.isPPC64() ? PPC::R4 : PPC::X4;
1421 }
1422 
1423 int PPCRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
1424   // FIXME: Most probably dwarf numbers differs for Linux and Darwin
1425   return PPCGenRegisterInfo::getDwarfRegNumFull(RegNum, 0);
1426 }
1427 
1428 #include "PPCGenRegisterInfo.inc"
1429 
1430