1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 * vim: set ts=8 sts=4 et sw=4 tw=99:
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 #ifndef jit_arm_SharedICHelpers_arm_h
8 #define jit_arm_SharedICHelpers_arm_h
9
10 #include "jit/BaselineFrame.h"
11 #include "jit/BaselineIC.h"
12 #include "jit/MacroAssembler.h"
13 #include "jit/SharedICRegisters.h"
14
15 namespace js {
16 namespace jit {
17
18 // Distance from sp to the top Value inside an IC stub (no return address on the stack on ARM).
19 static const size_t ICStackValueOffset = 0;
20
21 inline void
EmitRestoreTailCallReg(MacroAssembler & masm)22 EmitRestoreTailCallReg(MacroAssembler& masm)
23 {
24 // No-op on ARM because link register is always holding the return address.
25 }
26
27 inline void
EmitRepushTailCallReg(MacroAssembler & masm)28 EmitRepushTailCallReg(MacroAssembler& masm)
29 {
30 // No-op on ARM because link register is always holding the return address.
31 }
32
33 inline void
EmitCallIC(CodeOffset * patchOffset,MacroAssembler & masm)34 EmitCallIC(CodeOffset* patchOffset, MacroAssembler& masm)
35 {
36 // Move ICEntry offset into ICStubReg
37 CodeOffset offset = masm.movWithPatch(ImmWord(-1), ICStubReg);
38 *patchOffset = offset;
39
40 // Load stub pointer into ICStubReg
41 masm.loadPtr(Address(ICStubReg, ICEntry::offsetOfFirstStub()), ICStubReg);
42
43 // Load stubcode pointer from BaselineStubEntry.
44 // R2 won't be active when we call ICs, so we can use r0.
45 MOZ_ASSERT(R2 == ValueOperand(r1, r0));
46 masm.loadPtr(Address(ICStubReg, ICStub::offsetOfStubCode()), r0);
47
48 // Call the stubcode via a direct branch-and-link.
49 masm.ma_blx(r0);
50 }
51
52 inline void
53 EmitEnterTypeMonitorIC(MacroAssembler& masm,
54 size_t monitorStubOffset = ICMonitoredStub::offsetOfFirstMonitorStub())
55 {
56 // This is expected to be called from within an IC, when ICStubReg is
57 // properly initialized to point to the stub.
58 masm.loadPtr(Address(ICStubReg, (uint32_t) monitorStubOffset), ICStubReg);
59
60 // Load stubcode pointer from BaselineStubEntry.
61 // R2 won't be active when we call ICs, so we can use r0.
62 MOZ_ASSERT(R2 == ValueOperand(r1, r0));
63 masm.loadPtr(Address(ICStubReg, ICStub::offsetOfStubCode()), r0);
64
65 // Jump to the stubcode.
66 masm.branch(r0);
67 }
68
69 inline void
EmitReturnFromIC(MacroAssembler & masm)70 EmitReturnFromIC(MacroAssembler& masm)
71 {
72 masm.ma_mov(lr, pc);
73 }
74
75 inline void
EmitChangeICReturnAddress(MacroAssembler & masm,Register reg)76 EmitChangeICReturnAddress(MacroAssembler& masm, Register reg)
77 {
78 masm.ma_mov(reg, lr);
79 }
80
81 inline void
EmitBaselineTailCallVM(JitCode * target,MacroAssembler & masm,uint32_t argSize)82 EmitBaselineTailCallVM(JitCode* target, MacroAssembler& masm, uint32_t argSize)
83 {
84 // We assume during this that R0 and R1 have been pushed, and that R2 is
85 // unused.
86 MOZ_ASSERT(R2 == ValueOperand(r1, r0));
87
88 // Compute frame size.
89 masm.movePtr(BaselineFrameReg, r0);
90 masm.ma_add(Imm32(BaselineFrame::FramePointerOffset), r0);
91 masm.ma_sub(BaselineStackReg, r0);
92
93 // Store frame size without VMFunction arguments for GC marking.
94 masm.ma_sub(r0, Imm32(argSize), r1);
95 masm.store32(r1, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
96
97 // Push frame descriptor and perform the tail call.
98 // ICTailCallReg (lr) already contains the return address (as we keep
99 // it there through the stub calls), but the VMWrapper code being called
100 // expects the return address to also be pushed on the stack.
101 MOZ_ASSERT(ICTailCallReg == lr);
102 masm.makeFrameDescriptor(r0, JitFrame_BaselineJS);
103 masm.push(r0);
104 masm.push(lr);
105 masm.branch(target);
106 }
107
108 inline void
EmitIonTailCallVM(JitCode * target,MacroAssembler & masm,uint32_t stackSize)109 EmitIonTailCallVM(JitCode* target, MacroAssembler& masm, uint32_t stackSize)
110 {
111 // We assume during this that R0 and R1 have been pushed, and that R2 is
112 // unused.
113 MOZ_ASSERT(R2 == ValueOperand(r1, r0));
114
115 masm.loadPtr(Address(sp, stackSize), r0);
116 masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), r0);
117 masm.add32(Imm32(stackSize + JitStubFrameLayout::Size() - sizeof(intptr_t)), r0);
118
119 // Push frame descriptor and perform the tail call.
120 // ICTailCallReg (lr) already contains the return address (as we keep
121 // it there through the stub calls), but the VMWrapper code being called
122 // expects the return address to also be pushed on the stack.
123 MOZ_ASSERT(ICTailCallReg == lr);
124 masm.makeFrameDescriptor(r0, JitFrame_IonJS);
125 masm.push(r0);
126 masm.push(lr);
127 masm.branch(target);
128 }
129
130 inline void
EmitBaselineCreateStubFrameDescriptor(MacroAssembler & masm,Register reg)131 EmitBaselineCreateStubFrameDescriptor(MacroAssembler& masm, Register reg)
132 {
133 // Compute stub frame size. We have to add two pointers: the stub reg and
134 // previous frame pointer pushed by EmitEnterStubFrame.
135 masm.mov(BaselineFrameReg, reg);
136 masm.ma_add(Imm32(sizeof(void*) * 2), reg);
137 masm.ma_sub(BaselineStackReg, reg);
138
139 masm.makeFrameDescriptor(reg, JitFrame_BaselineStub);
140 }
141
142 inline void
EmitBaselineCallVM(JitCode * target,MacroAssembler & masm)143 EmitBaselineCallVM(JitCode* target, MacroAssembler& masm)
144 {
145 EmitBaselineCreateStubFrameDescriptor(masm, r0);
146 masm.push(r0);
147 masm.call(target);
148 }
149
150 inline void
EmitIonCallVM(JitCode * target,size_t stackSlots,MacroAssembler & masm)151 EmitIonCallVM(JitCode* target, size_t stackSlots, MacroAssembler& masm)
152 {
153 uint32_t descriptor = MakeFrameDescriptor(masm.framePushed(), JitFrame_IonStub);
154 masm.Push(Imm32(descriptor));
155 masm.callJit(target);
156
157 // Remove rest of the frame left on the stack. We remove the return address
158 // which is implicitly popped when returning.
159 size_t framePop = sizeof(ExitFrameLayout) - sizeof(void*);
160
161 // Pop arguments from framePushed.
162 masm.implicitPop(stackSlots * sizeof(void*) + framePop);
163 }
164
165 // Size of vales pushed by EmitEnterStubFrame.
166 static const uint32_t STUB_FRAME_SIZE = 4 * sizeof(void*);
167 static const uint32_t STUB_FRAME_SAVED_STUB_OFFSET = sizeof(void*);
168
169 inline void
EmitBaselineEnterStubFrame(MacroAssembler & masm,Register scratch)170 EmitBaselineEnterStubFrame(MacroAssembler& masm, Register scratch)
171 {
172 MOZ_ASSERT(scratch != ICTailCallReg);
173
174 // Compute frame size.
175 masm.mov(BaselineFrameReg, scratch);
176 masm.ma_add(Imm32(BaselineFrame::FramePointerOffset), scratch);
177 masm.ma_sub(BaselineStackReg, scratch);
178
179 masm.store32(scratch, Address(BaselineFrameReg, BaselineFrame::reverseOffsetOfFrameSize()));
180
181 // Note: when making changes here, don't forget to update STUB_FRAME_SIZE if
182 // needed.
183
184 // Push frame descriptor and return address.
185 masm.makeFrameDescriptor(scratch, JitFrame_BaselineJS);
186 masm.Push(scratch);
187 masm.Push(ICTailCallReg);
188
189 // Save old frame pointer, stack pointer and stub reg.
190 masm.Push(ICStubReg);
191 masm.Push(BaselineFrameReg);
192 masm.mov(BaselineStackReg, BaselineFrameReg);
193
194 // We pushed 4 words, so the stack is still aligned to 8 bytes.
195 masm.checkStackAlignment();
196 }
197
198 inline void
EmitIonEnterStubFrame(MacroAssembler & masm,Register scratch)199 EmitIonEnterStubFrame(MacroAssembler& masm, Register scratch)
200 {
201 MOZ_ASSERT(ICTailCallReg == lr);
202 masm.Push(ICTailCallReg);
203 masm.Push(ICStubReg);
204 }
205
206 inline void
207 EmitBaselineLeaveStubFrame(MacroAssembler& masm, bool calledIntoIon = false)
208 {
209 ScratchRegisterScope scratch(masm);
210
211 // Ion frames do not save and restore the frame pointer. If we called into
212 // Ion, we have to restore the stack pointer from the frame descriptor. If
213 // we performed a VM call, the descriptor has been popped already so in that
214 // case we use the frame pointer.
215 if (calledIntoIon) {
216 masm.Pop(scratch);
217 masm.rshiftPtr(Imm32(FRAMESIZE_SHIFT), scratch);
218 masm.add32(scratch, BaselineStackReg);
219 } else {
220 masm.mov(BaselineFrameReg, BaselineStackReg);
221 }
222
223 masm.Pop(BaselineFrameReg);
224 masm.Pop(ICStubReg);
225
226 // Load the return address.
227 masm.Pop(ICTailCallReg);
228
229 // Discard the frame descriptor.
230 masm.Pop(scratch);
231 }
232
233 inline void
EmitIonLeaveStubFrame(MacroAssembler & masm)234 EmitIonLeaveStubFrame(MacroAssembler& masm)
235 {
236 masm.Pop(ICStubReg);
237 masm.Pop(ICTailCallReg);
238 }
239
240 inline void
EmitStowICValues(MacroAssembler & masm,int values)241 EmitStowICValues(MacroAssembler& masm, int values)
242 {
243 MOZ_ASSERT(values >= 0 && values <= 2);
244 switch(values) {
245 case 1:
246 // Stow R0.
247 masm.Push(R0);
248 break;
249 case 2:
250 // Stow R0 and R1.
251 masm.Push(R0);
252 masm.Push(R1);
253 break;
254 }
255 }
256
257 inline void
258 EmitUnstowICValues(MacroAssembler& masm, int values, bool discard = false)
259 {
260 MOZ_ASSERT(values >= 0 && values <= 2);
261 switch(values) {
262 case 1:
263 // Unstow R0.
264 if (discard)
265 masm.addPtr(Imm32(sizeof(Value)), BaselineStackReg);
266 else
267 masm.popValue(R0);
268 break;
269 case 2:
270 // Unstow R0 and R1.
271 if (discard) {
272 masm.addPtr(Imm32(sizeof(Value) * 2), BaselineStackReg);
273 } else {
274 masm.popValue(R1);
275 masm.popValue(R0);
276 }
277 break;
278 }
279 masm.adjustFrame(-values * sizeof(Value));
280 }
281
282 inline void
EmitCallTypeUpdateIC(MacroAssembler & masm,JitCode * code,uint32_t objectOffset)283 EmitCallTypeUpdateIC(MacroAssembler& masm, JitCode* code, uint32_t objectOffset)
284 {
285 MOZ_ASSERT(R2 == ValueOperand(r1, r0));
286
287 // R0 contains the value that needs to be typechecked. The object we're
288 // updating is a boxed Value on the stack, at offset objectOffset from esp,
289 // excluding the return address.
290
291 // Save the current ICStubReg to stack, as well as the TailCallReg,
292 // since on ARM, the LR is live.
293 masm.push(ICStubReg);
294 masm.push(ICTailCallReg);
295
296 // This is expected to be called from within an IC, when ICStubReg is
297 // properly initialized to point to the stub.
298 masm.loadPtr(Address(ICStubReg, ICUpdatedStub::offsetOfFirstUpdateStub()),
299 ICStubReg);
300
301 // TODO: Change r0 uses below to use masm's configurable scratch register instead.
302
303 // Load stubcode pointer from ICStubReg into ICTailCallReg.
304 masm.loadPtr(Address(ICStubReg, ICStub::offsetOfStubCode()), r0);
305
306 // Call the stubcode.
307 masm.ma_blx(r0);
308
309 // Restore the old stub reg and tailcall reg.
310 masm.pop(ICTailCallReg);
311 masm.pop(ICStubReg);
312
313 // The update IC will store 0 or 1 in R1.scratchReg() reflecting if the
314 // value in R0 type-checked properly or not.
315 Label success;
316 masm.cmp32(R1.scratchReg(), Imm32(1));
317 masm.j(Assembler::Equal, &success);
318
319 // If the IC failed, then call the update fallback function.
320 EmitBaselineEnterStubFrame(masm, R1.scratchReg());
321
322 masm.loadValue(Address(BaselineStackReg, STUB_FRAME_SIZE + objectOffset), R1);
323
324 masm.Push(R0);
325 masm.Push(R1);
326 masm.Push(ICStubReg);
327
328 // Load previous frame pointer, push BaselineFrame*.
329 masm.loadPtr(Address(BaselineFrameReg, 0), R0.scratchReg());
330 masm.pushBaselineFramePtr(R0.scratchReg(), R0.scratchReg());
331
332 EmitBaselineCallVM(code, masm);
333 EmitBaselineLeaveStubFrame(masm);
334
335 // Success at end.
336 masm.bind(&success);
337 }
338
339 template <typename AddrType>
340 inline void
EmitPreBarrier(MacroAssembler & masm,const AddrType & addr,MIRType type)341 EmitPreBarrier(MacroAssembler& masm, const AddrType& addr, MIRType type)
342 {
343 // On ARM, lr is clobbered by patchableCallPreBarrier. Save it first.
344 masm.push(lr);
345 masm.patchableCallPreBarrier(addr, type);
346 masm.pop(lr);
347 }
348
349 inline void
EmitStubGuardFailure(MacroAssembler & masm)350 EmitStubGuardFailure(MacroAssembler& masm)
351 {
352 MOZ_ASSERT(R2 == ValueOperand(r1, r0));
353
354 // NOTE: This routine assumes that the stub guard code left the stack in the
355 // same state it was in when it was entered.
356
357 // BaselineStubEntry points to the current stub.
358
359 // Load next stub into ICStubReg.
360 masm.loadPtr(Address(ICStubReg, ICStub::offsetOfNext()), ICStubReg);
361
362 // Load stubcode pointer from BaselineStubEntry into scratch register.
363 masm.loadPtr(Address(ICStubReg, ICStub::offsetOfStubCode()), r0);
364
365 // Return address is already loaded, just jump to the next stubcode.
366 MOZ_ASSERT(ICTailCallReg == lr);
367 masm.branch(r0);
368 }
369
370
371 } // namespace jit
372 } // namespace js
373
374 #endif /* jit_arm_SharedICHelpers_arm_h */
375