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comparison: js/src/jit/arm/MoveEmitter-arm.cpp
js/src/jit/arm/MoveEmitter-arm.cpp
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| 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 #include "jit/arm/MoveEmitter-arm.h" | |
| 8 | |
| 9 using namespace js; | |
| 10 using namespace js::jit; | |
| 11 | |
| 12 MoveEmitterARM::MoveEmitterARM(MacroAssemblerARMCompat &masm) | |
| 13 : inCycle_(false), | |
| 14 masm(masm), | |
| 15 pushedAtCycle_(-1), | |
| 16 pushedAtSpill_(-1), | |
| 17 spilledReg_(InvalidReg), | |
| 18 spilledFloatReg_(InvalidFloatReg) | |
| 19 { | |
| 20 pushedAtStart_ = masm.framePushed(); | |
| 21 } | |
| 22 | |
| 23 void | |
| 24 MoveEmitterARM::emit(const MoveResolver &moves) | |
| 25 { | |
| 26 if (moves.hasCycles()) { | |
| 27 // Reserve stack for cycle resolution | |
| 28 masm.reserveStack(sizeof(double)); | |
| 29 pushedAtCycle_ = masm.framePushed(); | |
| 30 } | |
| 31 | |
| 32 for (size_t i = 0; i < moves.numMoves(); i++) | |
| 33 emit(moves.getMove(i)); | |
| 34 } | |
| 35 | |
| 36 MoveEmitterARM::~MoveEmitterARM() | |
| 37 { | |
| 38 assertDone(); | |
| 39 } | |
| 40 | |
| 41 Operand | |
| 42 MoveEmitterARM::cycleSlot() const | |
| 43 { | |
| 44 int offset = masm.framePushed() - pushedAtCycle_; | |
| 45 JS_ASSERT(offset < 4096 && offset > -4096); | |
| 46 return Operand(StackPointer, offset); | |
| 47 } | |
| 48 | |
| 49 // THIS IS ALWAYS AN LDRAddr. It should not be wrapped in an operand, methinks | |
| 50 Operand | |
| 51 MoveEmitterARM::spillSlot() const | |
| 52 { | |
| 53 int offset = masm.framePushed() - pushedAtSpill_; | |
| 54 JS_ASSERT(offset < 4096 && offset > -4096); | |
| 55 return Operand(StackPointer, offset); | |
| 56 } | |
| 57 | |
| 58 Operand | |
| 59 MoveEmitterARM::toOperand(const MoveOperand &operand, bool isFloat) const | |
| 60 { | |
| 61 if (operand.isMemoryOrEffectiveAddress()) { | |
| 62 if (operand.base() != StackPointer) { | |
| 63 JS_ASSERT(operand.disp() < 1024 && operand.disp() > -1024); | |
| 64 return Operand(operand.base(), operand.disp()); | |
| 65 } | |
| 66 | |
| 67 JS_ASSERT(operand.disp() >= 0); | |
| 68 | |
| 69 // Otherwise, the stack offset may need to be adjusted. | |
| 70 return Operand(StackPointer, operand.disp() + (masm.framePushed() - pushedAtStart_)); | |
| 71 } | |
| 72 | |
| 73 if (operand.isGeneralReg()) | |
| 74 return Operand(operand.reg()); | |
| 75 | |
| 76 JS_ASSERT(operand.isFloatReg()); | |
| 77 return Operand(operand.floatReg()); | |
| 78 } | |
| 79 | |
| 80 Register | |
| 81 MoveEmitterARM::tempReg() | |
| 82 { | |
| 83 if (spilledReg_ != InvalidReg) | |
| 84 return spilledReg_; | |
| 85 | |
| 86 // For now, just pick r12/ip as the eviction point. This is totally | |
| 87 // random, and if it ends up being bad, we can use actual heuristics later. | |
| 88 // r12 is actually a bad choice. it is the scratch register, which is frequently | |
| 89 // used for address computations, such as those found when we attempt to access | |
| 90 // values more than 4096 off of the stack pointer. | |
| 91 // instead, use lr, the LinkRegister. | |
| 92 spilledReg_ = r14; | |
| 93 if (pushedAtSpill_ == -1) { | |
| 94 masm.Push(spilledReg_); | |
| 95 pushedAtSpill_ = masm.framePushed(); | |
| 96 } else { | |
| 97 masm.ma_str(spilledReg_, spillSlot()); | |
| 98 } | |
| 99 return spilledReg_; | |
| 100 } | |
| 101 | |
| 102 void | |
| 103 MoveEmitterARM::breakCycle(const MoveOperand &from, const MoveOperand &to, MoveOp::Type type) | |
| 104 { | |
| 105 // There is some pattern: | |
| 106 // (A -> B) | |
| 107 // (B -> A) | |
| 108 // | |
| 109 // This case handles (A -> B), which we reach first. We save B, then allow | |
| 110 // the original move to continue. | |
| 111 switch (type) { | |
| 112 case MoveOp::FLOAT32: | |
| 113 case MoveOp::DOUBLE: | |
| 114 if (to.isMemory()) { | |
| 115 FloatRegister temp = ScratchFloatReg; | |
| 116 masm.ma_vldr(toOperand(to, true), temp); | |
| 117 masm.ma_vstr(temp, cycleSlot()); | |
| 118 } else { | |
| 119 masm.ma_vstr(to.floatReg(), cycleSlot()); | |
| 120 } | |
| 121 break; | |
| 122 case MoveOp::INT32: | |
| 123 case MoveOp::GENERAL: | |
| 124 // an non-vfp value | |
| 125 if (to.isMemory()) { | |
| 126 Register temp = tempReg(); | |
| 127 masm.ma_ldr(toOperand(to, false), temp); | |
| 128 masm.ma_str(temp, cycleSlot()); | |
| 129 } else { | |
| 130 if (to.reg() == spilledReg_) { | |
| 131 // If the destination was spilled, restore it first. | |
| 132 masm.ma_ldr(spillSlot(), spilledReg_); | |
| 133 spilledReg_ = InvalidReg; | |
| 134 } | |
| 135 masm.ma_str(to.reg(), cycleSlot()); | |
| 136 } | |
| 137 break; | |
| 138 default: | |
| 139 MOZ_ASSUME_UNREACHABLE("Unexpected move type"); | |
| 140 } | |
| 141 } | |
| 142 | |
| 143 void | |
| 144 MoveEmitterARM::completeCycle(const MoveOperand &from, const MoveOperand &to, MoveOp::Type type) | |
| 145 { | |
| 146 // There is some pattern: | |
| 147 // (A -> B) | |
| 148 // (B -> A) | |
| 149 // | |
| 150 // This case handles (B -> A), which we reach last. We emit a move from the | |
| 151 // saved value of B, to A. | |
| 152 switch (type) { | |
| 153 case MoveOp::FLOAT32: | |
| 154 case MoveOp::DOUBLE: | |
| 155 if (to.isMemory()) { | |
| 156 FloatRegister temp = ScratchFloatReg; | |
| 157 masm.ma_vldr(cycleSlot(), temp); | |
| 158 masm.ma_vstr(temp, toOperand(to, true)); | |
| 159 } else { | |
| 160 masm.ma_vldr(cycleSlot(), to.floatReg()); | |
| 161 } | |
| 162 break; | |
| 163 case MoveOp::INT32: | |
| 164 case MoveOp::GENERAL: | |
| 165 if (to.isMemory()) { | |
| 166 Register temp = tempReg(); | |
| 167 masm.ma_ldr(cycleSlot(), temp); | |
| 168 masm.ma_str(temp, toOperand(to, false)); | |
| 169 } else { | |
| 170 if (to.reg() == spilledReg_) { | |
| 171 // Make sure we don't re-clobber the spilled register later. | |
| 172 spilledReg_ = InvalidReg; | |
| 173 } | |
| 174 masm.ma_ldr(cycleSlot(), to.reg()); | |
| 175 } | |
| 176 break; | |
| 177 default: | |
| 178 MOZ_ASSUME_UNREACHABLE("Unexpected move type"); | |
| 179 } | |
| 180 } | |
| 181 | |
| 182 void | |
| 183 MoveEmitterARM::emitMove(const MoveOperand &from, const MoveOperand &to) | |
| 184 { | |
| 185 if (to.isGeneralReg() && to.reg() == spilledReg_) { | |
| 186 // If the destination is the spilled register, make sure we | |
| 187 // don't re-clobber its value. | |
| 188 spilledReg_ = InvalidReg; | |
| 189 } | |
| 190 | |
| 191 if (from.isGeneralReg()) { | |
| 192 if (from.reg() == spilledReg_) { | |
| 193 // If the source is a register that has been spilled, make sure | |
| 194 // to load the source back into that register. | |
| 195 masm.ma_ldr(spillSlot(), spilledReg_); | |
| 196 spilledReg_ = InvalidReg; | |
| 197 } | |
| 198 switch (toOperand(to, false).getTag()) { | |
| 199 case Operand::OP2: | |
| 200 // secretly must be a register | |
| 201 masm.ma_mov(from.reg(), to.reg()); | |
| 202 break; | |
| 203 case Operand::MEM: | |
| 204 masm.ma_str(from.reg(), toOperand(to, false)); | |
| 205 break; | |
| 206 default: | |
| 207 MOZ_ASSUME_UNREACHABLE("strange move!"); | |
| 208 } | |
| 209 } else if (to.isGeneralReg()) { | |
| 210 JS_ASSERT(from.isMemoryOrEffectiveAddress()); | |
| 211 if (from.isMemory()) | |
| 212 masm.ma_ldr(toOperand(from, false), to.reg()); | |
| 213 else | |
| 214 masm.ma_add(from.base(), Imm32(from.disp()), to.reg()); | |
| 215 } else { | |
| 216 // Memory to memory gpr move. | |
| 217 Register reg = tempReg(); | |
| 218 | |
| 219 JS_ASSERT(from.isMemoryOrEffectiveAddress()); | |
| 220 if (from.isMemory()) | |
| 221 masm.ma_ldr(toOperand(from, false), reg); | |
| 222 else | |
| 223 masm.ma_add(from.base(), Imm32(from.disp()), reg); | |
| 224 JS_ASSERT(to.base() != reg); | |
| 225 masm.ma_str(reg, toOperand(to, false)); | |
| 226 } | |
| 227 } | |
| 228 | |
| 229 void | |
| 230 MoveEmitterARM::emitFloat32Move(const MoveOperand &from, const MoveOperand &to) | |
| 231 { | |
| 232 if (from.isFloatReg()) { | |
| 233 if (to.isFloatReg()) | |
| 234 masm.ma_vmov_f32(from.floatReg(), to.floatReg()); | |
| 235 else | |
| 236 masm.ma_vstr(VFPRegister(from.floatReg()).singleOverlay(), | |
| 237 toOperand(to, true)); | |
| 238 } else if (to.isFloatReg()) { | |
| 239 masm.ma_vldr(toOperand(from, true), | |
| 240 VFPRegister(to.floatReg()).singleOverlay()); | |
| 241 } else { | |
| 242 // Memory to memory move. | |
| 243 JS_ASSERT(from.isMemory()); | |
| 244 FloatRegister reg = ScratchFloatReg; | |
| 245 masm.ma_vldr(toOperand(from, true), | |
| 246 VFPRegister(reg).singleOverlay()); | |
| 247 masm.ma_vstr(VFPRegister(reg).singleOverlay(), | |
| 248 toOperand(to, true)); | |
| 249 } | |
| 250 } | |
| 251 | |
| 252 void | |
| 253 MoveEmitterARM::emitDoubleMove(const MoveOperand &from, const MoveOperand &to) | |
| 254 { | |
| 255 if (from.isFloatReg()) { | |
| 256 if (to.isFloatReg()) | |
| 257 masm.ma_vmov(from.floatReg(), to.floatReg()); | |
| 258 else | |
| 259 masm.ma_vstr(from.floatReg(), toOperand(to, true)); | |
| 260 } else if (to.isFloatReg()) { | |
| 261 masm.ma_vldr(toOperand(from, true), to.floatReg()); | |
| 262 } else { | |
| 263 // Memory to memory move. | |
| 264 JS_ASSERT(from.isMemory()); | |
| 265 FloatRegister reg = ScratchFloatReg; | |
| 266 masm.ma_vldr(toOperand(from, true), reg); | |
| 267 masm.ma_vstr(reg, toOperand(to, true)); | |
| 268 } | |
| 269 } | |
| 270 | |
| 271 void | |
| 272 MoveEmitterARM::emit(const MoveOp &move) | |
| 273 { | |
| 274 const MoveOperand &from = move.from(); | |
| 275 const MoveOperand &to = move.to(); | |
| 276 | |
| 277 if (move.isCycleEnd()) { | |
| 278 JS_ASSERT(inCycle_); | |
| 279 completeCycle(from, to, move.type()); | |
| 280 inCycle_ = false; | |
| 281 return; | |
| 282 } | |
| 283 | |
| 284 if (move.isCycleBegin()) { | |
| 285 JS_ASSERT(!inCycle_); | |
| 286 breakCycle(from, to, move.endCycleType()); | |
| 287 inCycle_ = true; | |
| 288 } | |
| 289 | |
| 290 switch (move.type()) { | |
| 291 case MoveOp::FLOAT32: | |
| 292 emitFloat32Move(from, to); | |
| 293 break; | |
| 294 case MoveOp::DOUBLE: | |
| 295 emitDoubleMove(from, to); | |
| 296 break; | |
| 297 case MoveOp::INT32: | |
| 298 case MoveOp::GENERAL: | |
| 299 emitMove(from, to); | |
| 300 break; | |
| 301 default: | |
| 302 MOZ_ASSUME_UNREACHABLE("Unexpected move type"); | |
| 303 } | |
| 304 } | |
| 305 | |
| 306 void | |
| 307 MoveEmitterARM::assertDone() | |
| 308 { | |
| 309 JS_ASSERT(!inCycle_); | |
| 310 } | |
| 311 | |
| 312 void | |
| 313 MoveEmitterARM::finish() | |
| 314 { | |
| 315 assertDone(); | |
| 316 | |
| 317 if (pushedAtSpill_ != -1 && spilledReg_ != InvalidReg) | |
| 318 masm.ma_ldr(spillSlot(), spilledReg_); | |
| 319 masm.freeStack(masm.framePushed() - pushedAtStart_); | |
| 320 } |
