/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/lib/Target/MSP430/MSP430FrameLowering.cpp
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1 | | //===-- MSP430FrameLowering.cpp - MSP430 Frame Information ----------------===// |
2 | | // |
3 | | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | | // See https://llvm.org/LICENSE.txt for license information. |
5 | | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | | // |
7 | | //===----------------------------------------------------------------------===// |
8 | | // |
9 | | // This file contains the MSP430 implementation of TargetFrameLowering class. |
10 | | // |
11 | | //===----------------------------------------------------------------------===// |
12 | | |
13 | | #include "MSP430FrameLowering.h" |
14 | | #include "MSP430InstrInfo.h" |
15 | | #include "MSP430MachineFunctionInfo.h" |
16 | | #include "MSP430Subtarget.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/Target/TargetOptions.h" |
25 | | |
26 | | using namespace llvm; |
27 | | |
28 | 4.65k | bool MSP430FrameLowering::hasFP(const MachineFunction &MF) const { |
29 | 4.65k | const MachineFrameInfo &MFI = MF.getFrameInfo(); |
30 | 4.65k | |
31 | 4.65k | return (MF.getTarget().Options.DisableFramePointerElim(MF) || |
32 | 4.65k | MF.getFrameInfo().hasVarSizedObjects()4.39k || |
33 | 4.65k | MFI.isFrameAddressTaken()4.38k ); |
34 | 4.65k | } |
35 | | |
36 | 497 | bool MSP430FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const { |
37 | 497 | return !MF.getFrameInfo().hasVarSizedObjects(); |
38 | 497 | } |
39 | | |
40 | | void MSP430FrameLowering::emitPrologue(MachineFunction &MF, |
41 | 318 | MachineBasicBlock &MBB) const { |
42 | 318 | assert(&MF.front() == &MBB && "Shrink-wrapping not yet supported"); |
43 | 318 | MachineFrameInfo &MFI = MF.getFrameInfo(); |
44 | 318 | MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>(); |
45 | 318 | const MSP430InstrInfo &TII = |
46 | 318 | *static_cast<const MSP430InstrInfo *>(MF.getSubtarget().getInstrInfo()); |
47 | 318 | |
48 | 318 | MachineBasicBlock::iterator MBBI = MBB.begin(); |
49 | 318 | DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc()315 : DebugLoc()3 ; |
50 | 318 | |
51 | 318 | // Get the number of bytes to allocate from the FrameInfo. |
52 | 318 | uint64_t StackSize = MFI.getStackSize(); |
53 | 318 | |
54 | 318 | uint64_t NumBytes = 0; |
55 | 318 | if (hasFP(MF)) { |
56 | 20 | // Calculate required stack adjustment |
57 | 20 | uint64_t FrameSize = StackSize - 2; |
58 | 20 | NumBytes = FrameSize - MSP430FI->getCalleeSavedFrameSize(); |
59 | 20 | |
60 | 20 | // Get the offset of the stack slot for the EBP register... which is |
61 | 20 | // guaranteed to be the last slot by processFunctionBeforeFrameFinalized. |
62 | 20 | // Update the frame offset adjustment. |
63 | 20 | MFI.setOffsetAdjustment(-NumBytes); |
64 | 20 | |
65 | 20 | // Save FP into the appropriate stack slot... |
66 | 20 | BuildMI(MBB, MBBI, DL, TII.get(MSP430::PUSH16r)) |
67 | 20 | .addReg(MSP430::FP, RegState::Kill); |
68 | 20 | |
69 | 20 | // Update FP with the new base value... |
70 | 20 | BuildMI(MBB, MBBI, DL, TII.get(MSP430::MOV16rr), MSP430::FP) |
71 | 20 | .addReg(MSP430::SP); |
72 | 20 | |
73 | 20 | // Mark the FramePtr as live-in in every block except the entry. |
74 | 20 | for (MachineFunction::iterator I = std::next(MF.begin()), E = MF.end(); |
75 | 22 | I != E; ++I2 ) |
76 | 2 | I->addLiveIn(MSP430::FP); |
77 | 20 | |
78 | 20 | } else |
79 | 298 | NumBytes = StackSize - MSP430FI->getCalleeSavedFrameSize(); |
80 | 318 | |
81 | 318 | // Skip the callee-saved push instructions. |
82 | 400 | while (MBBI != MBB.end() && (MBBI->getOpcode() == MSP430::PUSH16r)397 ) |
83 | 82 | ++MBBI; |
84 | 318 | |
85 | 318 | if (MBBI != MBB.end()) |
86 | 315 | DL = MBBI->getDebugLoc(); |
87 | 318 | |
88 | 318 | if (NumBytes) { // adjust stack pointer: SP -= numbytes |
89 | 85 | // If there is an SUB16ri of SP immediately before this instruction, merge |
90 | 85 | // the two. |
91 | 85 | //NumBytes -= mergeSPUpdates(MBB, MBBI, true); |
92 | 85 | // If there is an ADD16ri or SUB16ri of SP immediately after this |
93 | 85 | // instruction, merge the two instructions. |
94 | 85 | // mergeSPUpdatesDown(MBB, MBBI, &NumBytes); |
95 | 85 | |
96 | 85 | if (NumBytes) { |
97 | 85 | MachineInstr *MI = |
98 | 85 | BuildMI(MBB, MBBI, DL, TII.get(MSP430::SUB16ri), MSP430::SP) |
99 | 85 | .addReg(MSP430::SP).addImm(NumBytes); |
100 | 85 | // The SRW implicit def is dead. |
101 | 85 | MI->getOperand(3).setIsDead(); |
102 | 85 | } |
103 | 85 | } |
104 | 318 | } |
105 | | |
106 | | void MSP430FrameLowering::emitEpilogue(MachineFunction &MF, |
107 | 320 | MachineBasicBlock &MBB) const { |
108 | 320 | const MachineFrameInfo &MFI = MF.getFrameInfo(); |
109 | 320 | MSP430MachineFunctionInfo *MSP430FI = MF.getInfo<MSP430MachineFunctionInfo>(); |
110 | 320 | const MSP430InstrInfo &TII = |
111 | 320 | *static_cast<const MSP430InstrInfo *>(MF.getSubtarget().getInstrInfo()); |
112 | 320 | |
113 | 320 | MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr(); |
114 | 320 | unsigned RetOpcode = MBBI->getOpcode(); |
115 | 320 | DebugLoc DL = MBBI->getDebugLoc(); |
116 | 320 | |
117 | 320 | switch (RetOpcode) { |
118 | 320 | case MSP430::RET: |
119 | 320 | case MSP430::RETI: break; // These are ok |
120 | 320 | default: |
121 | 0 | llvm_unreachable("Can only insert epilog into returning blocks"); |
122 | 320 | } |
123 | 320 | |
124 | 320 | // Get the number of bytes to allocate from the FrameInfo |
125 | 320 | uint64_t StackSize = MFI.getStackSize(); |
126 | 320 | unsigned CSSize = MSP430FI->getCalleeSavedFrameSize(); |
127 | 320 | uint64_t NumBytes = 0; |
128 | 320 | |
129 | 320 | if (hasFP(MF)) { |
130 | 20 | // Calculate required stack adjustment |
131 | 20 | uint64_t FrameSize = StackSize - 2; |
132 | 20 | NumBytes = FrameSize - CSSize; |
133 | 20 | |
134 | 20 | // pop FP. |
135 | 20 | BuildMI(MBB, MBBI, DL, TII.get(MSP430::POP16r), MSP430::FP); |
136 | 20 | } else |
137 | 300 | NumBytes = StackSize - CSSize; |
138 | 320 | |
139 | 320 | // Skip the callee-saved pop instructions. |
140 | 422 | while (MBBI != MBB.begin()) { |
141 | 394 | MachineBasicBlock::iterator PI = std::prev(MBBI); |
142 | 394 | unsigned Opc = PI->getOpcode(); |
143 | 394 | if (Opc != MSP430::POP16r && !PI->isTerminator()292 ) |
144 | 292 | break; |
145 | 102 | --MBBI; |
146 | 102 | } |
147 | 320 | |
148 | 320 | DL = MBBI->getDebugLoc(); |
149 | 320 | |
150 | 320 | // If there is an ADD16ri or SUB16ri of SP immediately before this |
151 | 320 | // instruction, merge the two instructions. |
152 | 320 | //if (NumBytes || MFI.hasVarSizedObjects()) |
153 | 320 | // mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes); |
154 | 320 | |
155 | 320 | if (MFI.hasVarSizedObjects()) { |
156 | 1 | BuildMI(MBB, MBBI, DL, |
157 | 1 | TII.get(MSP430::MOV16rr), MSP430::SP).addReg(MSP430::FP); |
158 | 1 | if (CSSize) { |
159 | 0 | MachineInstr *MI = |
160 | 0 | BuildMI(MBB, MBBI, DL, |
161 | 0 | TII.get(MSP430::SUB16ri), MSP430::SP) |
162 | 0 | .addReg(MSP430::SP).addImm(CSSize); |
163 | 0 | // The SRW implicit def is dead. |
164 | 0 | MI->getOperand(3).setIsDead(); |
165 | 0 | } |
166 | 319 | } else { |
167 | 319 | // adjust stack pointer back: SP += numbytes |
168 | 319 | if (NumBytes) { |
169 | 85 | MachineInstr *MI = |
170 | 85 | BuildMI(MBB, MBBI, DL, TII.get(MSP430::ADD16ri), MSP430::SP) |
171 | 85 | .addReg(MSP430::SP).addImm(NumBytes); |
172 | 85 | // The SRW implicit def is dead. |
173 | 85 | MI->getOperand(3).setIsDead(); |
174 | 85 | } |
175 | 319 | } |
176 | 320 | } |
177 | | |
178 | | // FIXME: Can we eleminate these in favour of generic code? |
179 | | bool |
180 | | MSP430FrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB, |
181 | | MachineBasicBlock::iterator MI, |
182 | | const std::vector<CalleeSavedInfo> &CSI, |
183 | 23 | const TargetRegisterInfo *TRI) const { |
184 | 23 | if (CSI.empty()) |
185 | 0 | return false; |
186 | 23 | |
187 | 23 | DebugLoc DL; |
188 | 23 | if (MI != MBB.end()) DL = MI->getDebugLoc(); |
189 | 23 | |
190 | 23 | MachineFunction &MF = *MBB.getParent(); |
191 | 23 | const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo(); |
192 | 23 | MSP430MachineFunctionInfo *MFI = MF.getInfo<MSP430MachineFunctionInfo>(); |
193 | 23 | MFI->setCalleeSavedFrameSize(CSI.size() * 2); |
194 | 23 | |
195 | 105 | for (unsigned i = CSI.size(); i != 0; --i82 ) { |
196 | 82 | unsigned Reg = CSI[i-1].getReg(); |
197 | 82 | // Add the callee-saved register as live-in. It's killed at the spill. |
198 | 82 | MBB.addLiveIn(Reg); |
199 | 82 | BuildMI(MBB, MI, DL, TII.get(MSP430::PUSH16r)) |
200 | 82 | .addReg(Reg, RegState::Kill); |
201 | 82 | } |
202 | 23 | return true; |
203 | 23 | } |
204 | | |
205 | | bool |
206 | | MSP430FrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB, |
207 | | MachineBasicBlock::iterator MI, |
208 | | std::vector<CalleeSavedInfo> &CSI, |
209 | 23 | const TargetRegisterInfo *TRI) const { |
210 | 23 | if (CSI.empty()) |
211 | 0 | return false; |
212 | 23 | |
213 | 23 | DebugLoc DL; |
214 | 23 | if (MI != MBB.end()) DL = MI->getDebugLoc(); |
215 | 23 | |
216 | 23 | MachineFunction &MF = *MBB.getParent(); |
217 | 23 | const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo(); |
218 | 23 | |
219 | 105 | for (unsigned i = 0, e = CSI.size(); i != e; ++i82 ) |
220 | 82 | BuildMI(MBB, MI, DL, TII.get(MSP430::POP16r), CSI[i].getReg()); |
221 | 23 | |
222 | 23 | return true; |
223 | 23 | } |
224 | | |
225 | | MachineBasicBlock::iterator MSP430FrameLowering::eliminateCallFramePseudoInstr( |
226 | | MachineFunction &MF, MachineBasicBlock &MBB, |
227 | 204 | MachineBasicBlock::iterator I) const { |
228 | 204 | const MSP430InstrInfo &TII = |
229 | 204 | *static_cast<const MSP430InstrInfo *>(MF.getSubtarget().getInstrInfo()); |
230 | 204 | unsigned StackAlign = getStackAlignment(); |
231 | 204 | |
232 | 204 | if (!hasReservedCallFrame(MF)) { |
233 | 4 | // If the stack pointer can be changed after prologue, turn the |
234 | 4 | // adjcallstackup instruction into a 'sub SP, <amt>' and the |
235 | 4 | // adjcallstackdown instruction into 'add SP, <amt>' |
236 | 4 | // TODO: consider using push / pop instead of sub + store / add |
237 | 4 | MachineInstr &Old = *I; |
238 | 4 | uint64_t Amount = TII.getFrameSize(Old); |
239 | 4 | if (Amount != 0) { |
240 | 0 | // We need to keep the stack aligned properly. To do this, we round the |
241 | 0 | // amount of space needed for the outgoing arguments up to the next |
242 | 0 | // alignment boundary. |
243 | 0 | Amount = (Amount+StackAlign-1)/StackAlign*StackAlign; |
244 | 0 |
|
245 | 0 | MachineInstr *New = nullptr; |
246 | 0 | if (Old.getOpcode() == TII.getCallFrameSetupOpcode()) { |
247 | 0 | New = |
248 | 0 | BuildMI(MF, Old.getDebugLoc(), TII.get(MSP430::SUB16ri), MSP430::SP) |
249 | 0 | .addReg(MSP430::SP) |
250 | 0 | .addImm(Amount); |
251 | 0 | } else { |
252 | 0 | assert(Old.getOpcode() == TII.getCallFrameDestroyOpcode()); |
253 | 0 | // factor out the amount the callee already popped. |
254 | 0 | Amount -= TII.getFramePoppedByCallee(Old); |
255 | 0 | if (Amount) |
256 | 0 | New = BuildMI(MF, Old.getDebugLoc(), TII.get(MSP430::ADD16ri), |
257 | 0 | MSP430::SP) |
258 | 0 | .addReg(MSP430::SP) |
259 | 0 | .addImm(Amount); |
260 | 0 | } |
261 | 0 |
|
262 | 0 | if (New) { |
263 | 0 | // The SRW implicit def is dead. |
264 | 0 | New->getOperand(3).setIsDead(); |
265 | 0 |
|
266 | 0 | // Replace the pseudo instruction with a new instruction... |
267 | 0 | MBB.insert(I, New); |
268 | 0 | } |
269 | 0 | } |
270 | 200 | } else if (I->getOpcode() == TII.getCallFrameDestroyOpcode()) { |
271 | 100 | // If we are performing frame pointer elimination and if the callee pops |
272 | 100 | // something off the stack pointer, add it back. |
273 | 100 | if (uint64_t CalleeAmt = TII.getFramePoppedByCallee(*I)) { |
274 | 0 | MachineInstr &Old = *I; |
275 | 0 | MachineInstr *New = |
276 | 0 | BuildMI(MF, Old.getDebugLoc(), TII.get(MSP430::SUB16ri), MSP430::SP) |
277 | 0 | .addReg(MSP430::SP) |
278 | 0 | .addImm(CalleeAmt); |
279 | 0 | // The SRW implicit def is dead. |
280 | 0 | New->getOperand(3).setIsDead(); |
281 | 0 |
|
282 | 0 | MBB.insert(I, New); |
283 | 0 | } |
284 | 100 | } |
285 | 204 | |
286 | 204 | return MBB.erase(I); |
287 | 204 | } |
288 | | |
289 | | void |
290 | | MSP430FrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF, |
291 | 318 | RegScavenger *) const { |
292 | 318 | // Create a frame entry for the FP register that must be saved. |
293 | 318 | if (hasFP(MF)) { |
294 | 20 | int FrameIdx = MF.getFrameInfo().CreateFixedObject(2, -4, true); |
295 | 20 | (void)FrameIdx; |
296 | 20 | assert(FrameIdx == MF.getFrameInfo().getObjectIndexBegin() && |
297 | 20 | "Slot for FP register must be last in order to be found!"); |
298 | 20 | } |
299 | 318 | } |