1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "codegen_arm64.h"
18 
19 #include <inttypes.h>
20 
21 #include <string>
22 
23 #include "dex/compiler_internals.h"
24 #include "dex/quick/mir_to_lir-inl.h"
25 #include "dex/reg_storage_eq.h"
26 
27 namespace art {
28 
29 static constexpr RegStorage core_regs_arr[] =
30     {rs_w0, rs_w1, rs_w2, rs_w3, rs_w4, rs_w5, rs_w6, rs_w7,
31      rs_w8, rs_w9, rs_w10, rs_w11, rs_w12, rs_w13, rs_w14, rs_w15,
32      rs_w16, rs_w17, rs_w18, rs_w19, rs_w20, rs_w21, rs_w22, rs_w23,
33      rs_w24, rs_w25, rs_w26, rs_w27, rs_w28, rs_w29, rs_w30, rs_w31,
34      rs_wzr};
35 static constexpr RegStorage core64_regs_arr[] =
36     {rs_x0, rs_x1, rs_x2, rs_x3, rs_x4, rs_x5, rs_x6, rs_x7,
37      rs_x8, rs_x9, rs_x10, rs_x11, rs_x12, rs_x13, rs_x14, rs_x15,
38      rs_x16, rs_x17, rs_x18, rs_x19, rs_x20, rs_x21, rs_x22, rs_x23,
39      rs_x24, rs_x25, rs_x26, rs_x27, rs_x28, rs_x29, rs_x30, rs_x31,
40      rs_xzr};
41 static constexpr RegStorage sp_regs_arr[] =
42     {rs_f0, rs_f1, rs_f2, rs_f3, rs_f4, rs_f5, rs_f6, rs_f7,
43      rs_f8, rs_f9, rs_f10, rs_f11, rs_f12, rs_f13, rs_f14, rs_f15,
44      rs_f16, rs_f17, rs_f18, rs_f19, rs_f20, rs_f21, rs_f22, rs_f23,
45      rs_f24, rs_f25, rs_f26, rs_f27, rs_f28, rs_f29, rs_f30, rs_f31};
46 static constexpr RegStorage dp_regs_arr[] =
47     {rs_d0, rs_d1, rs_d2, rs_d3, rs_d4, rs_d5, rs_d6, rs_d7,
48      rs_d8, rs_d9, rs_d10, rs_d11, rs_d12, rs_d13, rs_d14, rs_d15,
49      rs_d16, rs_d17, rs_d18, rs_d19, rs_d20, rs_d21, rs_d22, rs_d23,
50      rs_d24, rs_d25, rs_d26, rs_d27, rs_d28, rs_d29, rs_d30, rs_d31};
51 // Note: we are not able to call to C function since rs_xSELF is a special register need to be
52 // preserved but would be scratched by native functions follow aapcs64.
53 static constexpr RegStorage reserved_regs_arr[] =
54     {rs_wSUSPEND, rs_wSELF, rs_wsp, rs_wLR, rs_wzr};
55 static constexpr RegStorage reserved64_regs_arr[] =
56     {rs_xSUSPEND, rs_xSELF, rs_sp, rs_xLR, rs_xzr};
57 static constexpr RegStorage core_temps_arr[] =
58     {rs_w0, rs_w1, rs_w2, rs_w3, rs_w4, rs_w5, rs_w6, rs_w7,
59      rs_w8, rs_w9, rs_w10, rs_w11, rs_w12, rs_w13, rs_w14, rs_w15, rs_w16,
60      rs_w17};
61 static constexpr RegStorage core64_temps_arr[] =
62     {rs_x0, rs_x1, rs_x2, rs_x3, rs_x4, rs_x5, rs_x6, rs_x7,
63      rs_x8, rs_x9, rs_x10, rs_x11, rs_x12, rs_x13, rs_x14, rs_x15, rs_x16,
64      rs_x17};
65 static constexpr RegStorage sp_temps_arr[] =
66     {rs_f0, rs_f1, rs_f2, rs_f3, rs_f4, rs_f5, rs_f6, rs_f7,
67      rs_f16, rs_f17, rs_f18, rs_f19, rs_f20, rs_f21, rs_f22, rs_f23,
68      rs_f24, rs_f25, rs_f26, rs_f27, rs_f28, rs_f29, rs_f30, rs_f31};
69 static constexpr RegStorage dp_temps_arr[] =
70     {rs_d0, rs_d1, rs_d2, rs_d3, rs_d4, rs_d5, rs_d6, rs_d7,
71      rs_d16, rs_d17, rs_d18, rs_d19, rs_d20, rs_d21, rs_d22, rs_d23,
72      rs_d24, rs_d25, rs_d26, rs_d27, rs_d28, rs_d29, rs_d30, rs_d31};
73 
74 static constexpr ArrayRef<const RegStorage> core_regs(core_regs_arr);
75 static constexpr ArrayRef<const RegStorage> core64_regs(core64_regs_arr);
76 static constexpr ArrayRef<const RegStorage> sp_regs(sp_regs_arr);
77 static constexpr ArrayRef<const RegStorage> dp_regs(dp_regs_arr);
78 static constexpr ArrayRef<const RegStorage> reserved_regs(reserved_regs_arr);
79 static constexpr ArrayRef<const RegStorage> reserved64_regs(reserved64_regs_arr);
80 static constexpr ArrayRef<const RegStorage> core_temps(core_temps_arr);
81 static constexpr ArrayRef<const RegStorage> core64_temps(core64_temps_arr);
82 static constexpr ArrayRef<const RegStorage> sp_temps(sp_temps_arr);
83 static constexpr ArrayRef<const RegStorage> dp_temps(dp_temps_arr);
84 
LocCReturn()85 RegLocation Arm64Mir2Lir::LocCReturn() {
86   return arm_loc_c_return;
87 }
88 
LocCReturnRef()89 RegLocation Arm64Mir2Lir::LocCReturnRef() {
90   return arm_loc_c_return_ref;
91 }
92 
LocCReturnWide()93 RegLocation Arm64Mir2Lir::LocCReturnWide() {
94   return arm_loc_c_return_wide;
95 }
96 
LocCReturnFloat()97 RegLocation Arm64Mir2Lir::LocCReturnFloat() {
98   return arm_loc_c_return_float;
99 }
100 
LocCReturnDouble()101 RegLocation Arm64Mir2Lir::LocCReturnDouble() {
102   return arm_loc_c_return_double;
103 }
104 
105 // Return a target-dependent special register.
TargetReg(SpecialTargetRegister reg)106 RegStorage Arm64Mir2Lir::TargetReg(SpecialTargetRegister reg) {
107   RegStorage res_reg = RegStorage::InvalidReg();
108   switch (reg) {
109     case kSelf: res_reg = rs_wSELF; break;
110     case kSuspend: res_reg = rs_wSUSPEND; break;
111     case kLr: res_reg =  rs_wLR; break;
112     case kPc: res_reg = RegStorage::InvalidReg(); break;
113     case kSp: res_reg =  rs_wsp; break;
114     case kArg0: res_reg = rs_w0; break;
115     case kArg1: res_reg = rs_w1; break;
116     case kArg2: res_reg = rs_w2; break;
117     case kArg3: res_reg = rs_w3; break;
118     case kArg4: res_reg = rs_w4; break;
119     case kArg5: res_reg = rs_w5; break;
120     case kArg6: res_reg = rs_w6; break;
121     case kArg7: res_reg = rs_w7; break;
122     case kFArg0: res_reg = rs_f0; break;
123     case kFArg1: res_reg = rs_f1; break;
124     case kFArg2: res_reg = rs_f2; break;
125     case kFArg3: res_reg = rs_f3; break;
126     case kFArg4: res_reg = rs_f4; break;
127     case kFArg5: res_reg = rs_f5; break;
128     case kFArg6: res_reg = rs_f6; break;
129     case kFArg7: res_reg = rs_f7; break;
130     case kRet0: res_reg = rs_w0; break;
131     case kRet1: res_reg = rs_w1; break;
132     case kInvokeTgt: res_reg = rs_wLR; break;
133     case kHiddenArg: res_reg = rs_wIP1; break;
134     case kHiddenFpArg: res_reg = RegStorage::InvalidReg(); break;
135     case kCount: res_reg = RegStorage::InvalidReg(); break;
136     default: res_reg = RegStorage::InvalidReg();
137   }
138   return res_reg;
139 }
140 
141 /*
142  * Decode the register id. This routine makes assumptions on the encoding made by RegStorage.
143  */
GetRegMaskCommon(const RegStorage & reg) const144 ResourceMask Arm64Mir2Lir::GetRegMaskCommon(const RegStorage& reg) const {
145   // TODO(Arm64): this function depends too much on the internal RegStorage encoding. Refactor.
146 
147   // Check if the shape mask is zero (i.e. invalid).
148   if (UNLIKELY(reg == rs_wzr || reg == rs_xzr)) {
149     // The zero register is not a true register. It is just an immediate zero.
150     return kEncodeNone;
151   }
152 
153   return ResourceMask::Bit(
154       // FP register starts at bit position 32.
155       (reg.IsFloat() ? kArm64FPReg0 : 0) + reg.GetRegNum());
156 }
157 
GetPCUseDefEncoding() const158 ResourceMask Arm64Mir2Lir::GetPCUseDefEncoding() const {
159   // Note: On arm64, we are not able to set pc except branch instructions, which is regarded as a
160   //       kind of barrier. All other instructions only use pc, which has no dependency between any
161   //       of them. So it is fine to just return kEncodeNone here.
162   return kEncodeNone;
163 }
164 
165 // Arm64 specific setup.  TODO: inline?:
SetupTargetResourceMasks(LIR * lir,uint64_t flags,ResourceMask * use_mask,ResourceMask * def_mask)166 void Arm64Mir2Lir::SetupTargetResourceMasks(LIR* lir, uint64_t flags,
167                                             ResourceMask* use_mask, ResourceMask* def_mask) {
168   DCHECK_EQ(cu_->instruction_set, kArm64);
169   DCHECK(!lir->flags.use_def_invalid);
170 
171   // Note: REG_USE_PC is ignored, the reason is the same with what we do in GetPCUseDefEncoding().
172   // These flags are somewhat uncommon - bypass if we can.
173   if ((flags & (REG_DEF_SP | REG_USE_SP | REG_DEF_LR)) != 0) {
174     if (flags & REG_DEF_SP) {
175       def_mask->SetBit(kArm64RegSP);
176     }
177 
178     if (flags & REG_USE_SP) {
179       use_mask->SetBit(kArm64RegSP);
180     }
181 
182     if (flags & REG_DEF_LR) {
183       def_mask->SetBit(kArm64RegLR);
184     }
185   }
186 }
187 
ArmConditionEncoding(ConditionCode ccode)188 ArmConditionCode Arm64Mir2Lir::ArmConditionEncoding(ConditionCode ccode) {
189   ArmConditionCode res;
190   switch (ccode) {
191     case kCondEq: res = kArmCondEq; break;
192     case kCondNe: res = kArmCondNe; break;
193     case kCondCs: res = kArmCondCs; break;
194     case kCondCc: res = kArmCondCc; break;
195     case kCondUlt: res = kArmCondCc; break;
196     case kCondUge: res = kArmCondCs; break;
197     case kCondMi: res = kArmCondMi; break;
198     case kCondPl: res = kArmCondPl; break;
199     case kCondVs: res = kArmCondVs; break;
200     case kCondVc: res = kArmCondVc; break;
201     case kCondHi: res = kArmCondHi; break;
202     case kCondLs: res = kArmCondLs; break;
203     case kCondGe: res = kArmCondGe; break;
204     case kCondLt: res = kArmCondLt; break;
205     case kCondGt: res = kArmCondGt; break;
206     case kCondLe: res = kArmCondLe; break;
207     case kCondAl: res = kArmCondAl; break;
208     case kCondNv: res = kArmCondNv; break;
209     default:
210       LOG(FATAL) << "Bad condition code " << ccode;
211       res = static_cast<ArmConditionCode>(0);  // Quiet gcc
212   }
213   return res;
214 }
215 
216 static const char *shift_names[4] = {
217   "lsl",
218   "lsr",
219   "asr",
220   "ror"
221 };
222 
223 static const char* extend_names[8] = {
224   "uxtb",
225   "uxth",
226   "uxtw",
227   "uxtx",
228   "sxtb",
229   "sxth",
230   "sxtw",
231   "sxtx",
232 };
233 
234 /* Decode and print a register extension (e.g. ", uxtb #1") */
DecodeRegExtendOrShift(int operand,char * buf,size_t buf_size)235 static void DecodeRegExtendOrShift(int operand, char *buf, size_t buf_size) {
236   if ((operand & (1 << 6)) == 0) {
237     const char *shift_name = shift_names[(operand >> 7) & 0x3];
238     int amount = operand & 0x3f;
239     snprintf(buf, buf_size, ", %s #%d", shift_name, amount);
240   } else {
241     const char *extend_name = extend_names[(operand >> 3) & 0x7];
242     int amount = operand & 0x7;
243     if (amount == 0) {
244       snprintf(buf, buf_size, ", %s", extend_name);
245     } else {
246       snprintf(buf, buf_size, ", %s #%d", extend_name, amount);
247     }
248   }
249 }
250 
251 #define BIT_MASK(w) ((UINT64_C(1) << (w)) - UINT64_C(1))
252 
RotateRight(uint64_t value,unsigned rotate,unsigned width)253 static uint64_t RotateRight(uint64_t value, unsigned rotate, unsigned width) {
254   DCHECK_LE(width, 64U);
255   rotate &= 63;
256   value = value & BIT_MASK(width);
257   return ((value & BIT_MASK(rotate)) << (width - rotate)) | (value >> rotate);
258 }
259 
RepeatBitsAcrossReg(bool is_wide,uint64_t value,unsigned width)260 static uint64_t RepeatBitsAcrossReg(bool is_wide, uint64_t value, unsigned width) {
261   unsigned i;
262   unsigned reg_size = (is_wide) ? 64 : 32;
263   uint64_t result = value & BIT_MASK(width);
264   for (i = width; i < reg_size; i *= 2) {
265     result |= (result << i);
266   }
267   DCHECK_EQ(i, reg_size);
268   return result;
269 }
270 
271 /**
272  * @brief Decode an immediate in the form required by logical instructions.
273  *
274  * @param is_wide Whether @p value encodes a 64-bit (as opposed to 32-bit) immediate.
275  * @param value The encoded logical immediates that is to be decoded.
276  * @return The decoded logical immediate.
277  * @note This is the inverse of Arm64Mir2Lir::EncodeLogicalImmediate().
278  */
DecodeLogicalImmediate(bool is_wide,int value)279 uint64_t Arm64Mir2Lir::DecodeLogicalImmediate(bool is_wide, int value) {
280   unsigned n     = (value >> 12) & 0x01;
281   unsigned imm_r = (value >>  6) & 0x3f;
282   unsigned imm_s = (value >>  0) & 0x3f;
283 
284   // An integer is constructed from the n, imm_s and imm_r bits according to
285   // the following table:
286   //
287   // N   imms immr  size S             R
288   // 1 ssssss rrrrrr 64  UInt(ssssss) UInt(rrrrrr)
289   // 0 0sssss xrrrrr 32  UInt(sssss)  UInt(rrrrr)
290   // 0 10ssss xxrrrr 16  UInt(ssss)   UInt(rrrr)
291   // 0 110sss xxxrrr 8   UInt(sss)    UInt(rrr)
292   // 0 1110ss xxxxrr 4   UInt(ss)     UInt(rr)
293   // 0 11110s xxxxxr 2   UInt(s)      UInt(r)
294   // (s bits must not be all set)
295   //
296   // A pattern is constructed of size bits, where the least significant S+1
297   // bits are set. The pattern is rotated right by R, and repeated across a
298   // 32 or 64-bit value, depending on destination register width.
299 
300   if (n == 1) {
301     DCHECK_NE(imm_s, 0x3fU);
302     uint64_t bits = BIT_MASK(imm_s + 1);
303     return RotateRight(bits, imm_r, 64);
304   } else {
305     DCHECK_NE((imm_s >> 1), 0x1fU);
306     for (unsigned width = 0x20; width >= 0x2; width >>= 1) {
307       if ((imm_s & width) == 0) {
308         unsigned mask = (unsigned)(width - 1);
309         DCHECK_NE((imm_s & mask), mask);
310         uint64_t bits = BIT_MASK((imm_s & mask) + 1);
311         return RepeatBitsAcrossReg(is_wide, RotateRight(bits, imm_r & mask, width), width);
312       }
313     }
314   }
315   return 0;
316 }
317 
318 /**
319  * @brief Decode an 8-bit single point number encoded with EncodeImmSingle().
320  */
DecodeImmSingle(uint8_t small_float)321 static float DecodeImmSingle(uint8_t small_float) {
322   int mantissa = (small_float & 0x0f) + 0x10;
323   int sign = ((small_float & 0x80) == 0) ? 1 : -1;
324   float signed_mantissa = static_cast<float>(sign*mantissa);
325   int exponent = (((small_float >> 4) & 0x7) + 4) & 0x7;
326   return signed_mantissa*static_cast<float>(1 << exponent)*0.0078125f;
327 }
328 
329 static const char* cc_names[] = {"eq", "ne", "cs", "cc", "mi", "pl", "vs", "vc",
330                                  "hi", "ls", "ge", "lt", "gt", "le", "al", "nv"};
331 /*
332  * Interpret a format string and build a string no longer than size
333  * See format key in assemble_arm64.cc.
334  */
BuildInsnString(const char * fmt,LIR * lir,unsigned char * base_addr)335 std::string Arm64Mir2Lir::BuildInsnString(const char* fmt, LIR* lir, unsigned char* base_addr) {
336   std::string buf;
337   const char* fmt_end = &fmt[strlen(fmt)];
338   char tbuf[256];
339   const char* name;
340   char nc;
341   while (fmt < fmt_end) {
342     int operand;
343     if (*fmt == '!') {
344       fmt++;
345       DCHECK_LT(fmt, fmt_end);
346       nc = *fmt++;
347       if (nc == '!') {
348         strcpy(tbuf, "!");
349       } else {
350          DCHECK_LT(fmt, fmt_end);
351          DCHECK_LT(static_cast<unsigned>(nc-'0'), 4U);
352          operand = lir->operands[nc-'0'];
353          switch (*fmt++) {
354            case 'e':  {
355                // Omit ", uxtw #0" in strings like "add w0, w1, w3, uxtw #0" and
356                // ", uxtx #0" in strings like "add x0, x1, x3, uxtx #0"
357                int omittable = ((IS_WIDE(lir->opcode)) ? EncodeExtend(kA64Uxtw, 0) :
358                                 EncodeExtend(kA64Uxtw, 0));
359                if (LIKELY(operand == omittable)) {
360                  strcpy(tbuf, "");
361                } else {
362                  DecodeRegExtendOrShift(operand, tbuf, arraysize(tbuf));
363                }
364              }
365              break;
366            case 'o':
367              // Omit ", lsl #0"
368              if (LIKELY(operand == EncodeShift(kA64Lsl, 0))) {
369                strcpy(tbuf, "");
370              } else {
371                DecodeRegExtendOrShift(operand, tbuf, arraysize(tbuf));
372              }
373              break;
374            case 'B':
375              switch (operand) {
376                case kSY:
377                  name = "sy";
378                  break;
379                case kST:
380                  name = "st";
381                  break;
382                case kISH:
383                  name = "ish";
384                  break;
385                case kISHST:
386                  name = "ishst";
387                  break;
388                case kNSH:
389                  name = "nsh";
390                  break;
391                case kNSHST:
392                  name = "shst";
393                  break;
394                default:
395                  name = "DecodeError2";
396                  break;
397              }
398              strcpy(tbuf, name);
399              break;
400            case 's':
401              snprintf(tbuf, arraysize(tbuf), "s%d", operand & RegStorage::kRegNumMask);
402              break;
403            case 'S':
404              snprintf(tbuf, arraysize(tbuf), "d%d", operand & RegStorage::kRegNumMask);
405              break;
406            case 'f':
407              snprintf(tbuf, arraysize(tbuf), "%c%d", (IS_FWIDE(lir->opcode)) ? 'd' : 's',
408                       operand & RegStorage::kRegNumMask);
409              break;
410            case 'l': {
411                bool is_wide = IS_WIDE(lir->opcode);
412                uint64_t imm = DecodeLogicalImmediate(is_wide, operand);
413                snprintf(tbuf, arraysize(tbuf), "%" PRId64 " (%#" PRIx64 ")", imm, imm);
414              }
415              break;
416            case 'I':
417              snprintf(tbuf, arraysize(tbuf), "%f", DecodeImmSingle(operand));
418              break;
419            case 'M':
420              if (LIKELY(operand == 0))
421                strcpy(tbuf, "");
422              else
423                snprintf(tbuf, arraysize(tbuf), ", lsl #%d", 16*operand);
424              break;
425            case 'd':
426              snprintf(tbuf, arraysize(tbuf), "%d", operand);
427              break;
428            case 'w':
429              if (LIKELY(operand != rwzr))
430                snprintf(tbuf, arraysize(tbuf), "w%d", operand & RegStorage::kRegNumMask);
431              else
432                strcpy(tbuf, "wzr");
433              break;
434            case 'W':
435              if (LIKELY(operand != rwsp))
436                snprintf(tbuf, arraysize(tbuf), "w%d", operand & RegStorage::kRegNumMask);
437              else
438                strcpy(tbuf, "wsp");
439              break;
440            case 'x':
441              if (LIKELY(operand != rxzr))
442                snprintf(tbuf, arraysize(tbuf), "x%d", operand & RegStorage::kRegNumMask);
443              else
444                strcpy(tbuf, "xzr");
445              break;
446            case 'X':
447              if (LIKELY(operand != rsp))
448                snprintf(tbuf, arraysize(tbuf), "x%d", operand & RegStorage::kRegNumMask);
449              else
450                strcpy(tbuf, "sp");
451              break;
452            case 'D':
453              snprintf(tbuf, arraysize(tbuf), "%d", operand*((IS_WIDE(lir->opcode)) ? 8 : 4));
454              break;
455            case 'E':
456              snprintf(tbuf, arraysize(tbuf), "%d", operand*4);
457              break;
458            case 'F':
459              snprintf(tbuf, arraysize(tbuf), "%d", operand*2);
460              break;
461            case 'G':
462              if (LIKELY(operand == 0))
463                strcpy(tbuf, "");
464              else
465                strcpy(tbuf, (IS_WIDE(lir->opcode)) ? ", lsl #3" : ", lsl #2");
466              break;
467            case 'c':
468              strcpy(tbuf, cc_names[operand]);
469              break;
470            case 't':
471              snprintf(tbuf, arraysize(tbuf), "0x%08" PRIxPTR " (L%p)",
472                  reinterpret_cast<uintptr_t>(base_addr) + lir->offset + (operand << 2),
473                  lir->target);
474              break;
475            case 'r': {
476                bool is_wide = IS_WIDE(lir->opcode);
477                if (LIKELY(operand != rwzr && operand != rxzr)) {
478                  snprintf(tbuf, arraysize(tbuf), "%c%d", (is_wide) ? 'x' : 'w',
479                           operand & RegStorage::kRegNumMask);
480                } else {
481                  strcpy(tbuf, (is_wide) ? "xzr" : "wzr");
482                }
483              }
484              break;
485            case 'R': {
486                bool is_wide = IS_WIDE(lir->opcode);
487                if (LIKELY(operand != rwsp && operand != rsp)) {
488                  snprintf(tbuf, arraysize(tbuf), "%c%d", (is_wide) ? 'x' : 'w',
489                           operand & RegStorage::kRegNumMask);
490                } else {
491                  strcpy(tbuf, (is_wide) ? "sp" : "wsp");
492                }
493              }
494              break;
495            case 'p':
496              snprintf(tbuf, arraysize(tbuf), ".+%d (addr %#" PRIxPTR ")", 4*operand,
497                       reinterpret_cast<uintptr_t>(base_addr) + lir->offset + 4*operand);
498              break;
499            case 'T':
500              if (LIKELY(operand == 0))
501                strcpy(tbuf, "");
502              else if (operand == 1)
503                strcpy(tbuf, ", lsl #12");
504              else
505                strcpy(tbuf, ", DecodeError3");
506              break;
507            default:
508              strcpy(tbuf, "DecodeError1");
509              break;
510         }
511         buf += tbuf;
512       }
513     } else {
514        buf += *fmt++;
515     }
516   }
517   return buf;
518 }
519 
DumpResourceMask(LIR * arm_lir,const ResourceMask & mask,const char * prefix)520 void Arm64Mir2Lir::DumpResourceMask(LIR* arm_lir, const ResourceMask& mask, const char* prefix) {
521   char buf[256];
522   buf[0] = 0;
523 
524   if (mask.Equals(kEncodeAll)) {
525     strcpy(buf, "all");
526   } else {
527     char num[8];
528     int i;
529 
530     for (i = 0; i < kArm64RegEnd; i++) {
531       if (mask.HasBit(i)) {
532         snprintf(num, arraysize(num), "%d ", i);
533         strcat(buf, num);
534       }
535     }
536 
537     if (mask.HasBit(ResourceMask::kCCode)) {
538       strcat(buf, "cc ");
539     }
540     if (mask.HasBit(ResourceMask::kFPStatus)) {
541       strcat(buf, "fpcc ");
542     }
543 
544     /* Memory bits */
545     if (arm_lir && (mask.HasBit(ResourceMask::kDalvikReg))) {
546       snprintf(buf + strlen(buf), arraysize(buf) - strlen(buf), "dr%d%s",
547                DECODE_ALIAS_INFO_REG(arm_lir->flags.alias_info),
548                DECODE_ALIAS_INFO_WIDE(arm_lir->flags.alias_info) ? "(+1)" : "");
549     }
550     if (mask.HasBit(ResourceMask::kLiteral)) {
551       strcat(buf, "lit ");
552     }
553 
554     if (mask.HasBit(ResourceMask::kHeapRef)) {
555       strcat(buf, "heap ");
556     }
557     if (mask.HasBit(ResourceMask::kMustNotAlias)) {
558       strcat(buf, "noalias ");
559     }
560   }
561   if (buf[0]) {
562     LOG(INFO) << prefix << ": " << buf;
563   }
564 }
565 
IsUnconditionalBranch(LIR * lir)566 bool Arm64Mir2Lir::IsUnconditionalBranch(LIR* lir) {
567   return (lir->opcode == kA64B1t);
568 }
569 
RegClassForFieldLoadStore(OpSize size,bool is_volatile)570 RegisterClass Arm64Mir2Lir::RegClassForFieldLoadStore(OpSize size, bool is_volatile) {
571   if (UNLIKELY(is_volatile)) {
572     // On arm64, fp register load/store is atomic only for single bytes.
573     if (size != kSignedByte && size != kUnsignedByte) {
574       return (size == kReference) ? kRefReg : kCoreReg;
575     }
576   }
577   return RegClassBySize(size);
578 }
579 
Arm64Mir2Lir(CompilationUnit * cu,MIRGraph * mir_graph,ArenaAllocator * arena)580 Arm64Mir2Lir::Arm64Mir2Lir(CompilationUnit* cu, MIRGraph* mir_graph, ArenaAllocator* arena)
581     : Mir2Lir(cu, mir_graph, arena) {
582   // Sanity check - make sure encoding map lines up.
583   for (int i = 0; i < kA64Last; i++) {
584     if (UNWIDE(Arm64Mir2Lir::EncodingMap[i].opcode) != i) {
585       LOG(FATAL) << "Encoding order for " << Arm64Mir2Lir::EncodingMap[i].name
586                  << " is wrong: expecting " << i << ", seeing "
587                  << static_cast<int>(Arm64Mir2Lir::EncodingMap[i].opcode);
588     }
589   }
590 }
591 
Arm64CodeGenerator(CompilationUnit * const cu,MIRGraph * const mir_graph,ArenaAllocator * const arena)592 Mir2Lir* Arm64CodeGenerator(CompilationUnit* const cu, MIRGraph* const mir_graph,
593                             ArenaAllocator* const arena) {
594   return new Arm64Mir2Lir(cu, mir_graph, arena);
595 }
596 
CompilerInitializeRegAlloc()597 void Arm64Mir2Lir::CompilerInitializeRegAlloc() {
598   reg_pool_ = new (arena_) RegisterPool(this, arena_, core_regs, core64_regs, sp_regs, dp_regs,
599                                         reserved_regs, reserved64_regs, core_temps, core64_temps,
600                                         sp_temps, dp_temps);
601 
602   // Target-specific adjustments.
603   // Alias single precision float registers to corresponding double registers.
604   GrowableArray<RegisterInfo*>::Iterator fp_it(&reg_pool_->sp_regs_);
605   for (RegisterInfo* info = fp_it.Next(); info != nullptr; info = fp_it.Next()) {
606     int fp_reg_num = info->GetReg().GetRegNum();
607     RegStorage dp_reg = RegStorage::FloatSolo64(fp_reg_num);
608     RegisterInfo* dp_reg_info = GetRegInfo(dp_reg);
609     // Double precision register's master storage should refer to itself.
610     DCHECK_EQ(dp_reg_info, dp_reg_info->Master());
611     // Redirect single precision's master storage to master.
612     info->SetMaster(dp_reg_info);
613     // Singles should show a single 32-bit mask bit, at first referring to the low half.
614     DCHECK_EQ(info->StorageMask(), 0x1U);
615   }
616 
617   // Alias 32bit W registers to corresponding 64bit X registers.
618   GrowableArray<RegisterInfo*>::Iterator w_it(&reg_pool_->core_regs_);
619   for (RegisterInfo* info = w_it.Next(); info != nullptr; info = w_it.Next()) {
620     int x_reg_num = info->GetReg().GetRegNum();
621     RegStorage x_reg = RegStorage::Solo64(x_reg_num);
622     RegisterInfo* x_reg_info = GetRegInfo(x_reg);
623     // 64bit X register's master storage should refer to itself.
624     DCHECK_EQ(x_reg_info, x_reg_info->Master());
625     // Redirect 32bit W master storage to 64bit X.
626     info->SetMaster(x_reg_info);
627     // 32bit W should show a single 32-bit mask bit, at first referring to the low half.
628     DCHECK_EQ(info->StorageMask(), 0x1U);
629   }
630 
631   // Don't start allocating temps at r0/s0/d0 or you may clobber return regs in early-exit methods.
632   // TODO: adjust when we roll to hard float calling convention.
633   reg_pool_->next_core_reg_ = 2;
634   reg_pool_->next_sp_reg_ = 0;
635   reg_pool_->next_dp_reg_ = 0;
636 }
637 
638 /*
639  * TUNING: is true leaf?  Can't just use METHOD_IS_LEAF to determine as some
640  * instructions might call out to C/assembly helper functions.  Until
641  * machinery is in place, always spill lr.
642  */
643 
AdjustSpillMask()644 void Arm64Mir2Lir::AdjustSpillMask() {
645   core_spill_mask_ |= (1 << rs_xLR.GetRegNum());
646   num_core_spills_++;
647 }
648 
649 /* Clobber all regs that might be used by an external C call */
ClobberCallerSave()650 void Arm64Mir2Lir::ClobberCallerSave() {
651   Clobber(rs_x0);
652   Clobber(rs_x1);
653   Clobber(rs_x2);
654   Clobber(rs_x3);
655   Clobber(rs_x4);
656   Clobber(rs_x5);
657   Clobber(rs_x6);
658   Clobber(rs_x7);
659   Clobber(rs_x8);
660   Clobber(rs_x9);
661   Clobber(rs_x10);
662   Clobber(rs_x11);
663   Clobber(rs_x12);
664   Clobber(rs_x13);
665   Clobber(rs_x14);
666   Clobber(rs_x15);
667   Clobber(rs_x16);
668   Clobber(rs_x17);
669   Clobber(rs_x30);
670 
671   Clobber(rs_f0);
672   Clobber(rs_f1);
673   Clobber(rs_f2);
674   Clobber(rs_f3);
675   Clobber(rs_f4);
676   Clobber(rs_f5);
677   Clobber(rs_f6);
678   Clobber(rs_f7);
679   Clobber(rs_f16);
680   Clobber(rs_f17);
681   Clobber(rs_f18);
682   Clobber(rs_f19);
683   Clobber(rs_f20);
684   Clobber(rs_f21);
685   Clobber(rs_f22);
686   Clobber(rs_f23);
687   Clobber(rs_f24);
688   Clobber(rs_f25);
689   Clobber(rs_f26);
690   Clobber(rs_f27);
691   Clobber(rs_f28);
692   Clobber(rs_f29);
693   Clobber(rs_f30);
694   Clobber(rs_f31);
695 }
696 
GetReturnWideAlt()697 RegLocation Arm64Mir2Lir::GetReturnWideAlt() {
698   RegLocation res = LocCReturnWide();
699   res.reg.SetReg(rx2);
700   res.reg.SetHighReg(rx3);
701   Clobber(rs_x2);
702   Clobber(rs_x3);
703   MarkInUse(rs_x2);
704   MarkInUse(rs_x3);
705   MarkWide(res.reg);
706   return res;
707 }
708 
GetReturnAlt()709 RegLocation Arm64Mir2Lir::GetReturnAlt() {
710   RegLocation res = LocCReturn();
711   res.reg.SetReg(rx1);
712   Clobber(rs_x1);
713   MarkInUse(rs_x1);
714   return res;
715 }
716 
717 /* To be used when explicitly managing register use */
LockCallTemps()718 void Arm64Mir2Lir::LockCallTemps() {
719   // TODO: needs cleanup.
720   LockTemp(rs_x0);
721   LockTemp(rs_x1);
722   LockTemp(rs_x2);
723   LockTemp(rs_x3);
724   LockTemp(rs_x4);
725   LockTemp(rs_x5);
726   LockTemp(rs_x6);
727   LockTemp(rs_x7);
728   LockTemp(rs_f0);
729   LockTemp(rs_f1);
730   LockTemp(rs_f2);
731   LockTemp(rs_f3);
732   LockTemp(rs_f4);
733   LockTemp(rs_f5);
734   LockTemp(rs_f6);
735   LockTemp(rs_f7);
736 }
737 
738 /* To be used when explicitly managing register use */
FreeCallTemps()739 void Arm64Mir2Lir::FreeCallTemps() {
740   // TODO: needs cleanup.
741   FreeTemp(rs_x0);
742   FreeTemp(rs_x1);
743   FreeTemp(rs_x2);
744   FreeTemp(rs_x3);
745   FreeTemp(rs_x4);
746   FreeTemp(rs_x5);
747   FreeTemp(rs_x6);
748   FreeTemp(rs_x7);
749   FreeTemp(rs_f0);
750   FreeTemp(rs_f1);
751   FreeTemp(rs_f2);
752   FreeTemp(rs_f3);
753   FreeTemp(rs_f4);
754   FreeTemp(rs_f5);
755   FreeTemp(rs_f6);
756   FreeTemp(rs_f7);
757   FreeTemp(TargetReg(kHiddenArg));
758 }
759 
LoadHelper(QuickEntrypointEnum trampoline)760 RegStorage Arm64Mir2Lir::LoadHelper(QuickEntrypointEnum trampoline) {
761   // TODO(Arm64): use LoadWordDisp instead.
762   //   e.g. LoadWordDisp(rs_rA64_SELF, offset.Int32Value(), rs_rA64_LR);
763   LoadBaseDisp(rs_xSELF, GetThreadOffset<8>(trampoline).Int32Value(), rs_xLR, k64, kNotVolatile);
764   return rs_xLR;
765 }
766 
CheckSuspendUsingLoad()767 LIR* Arm64Mir2Lir::CheckSuspendUsingLoad() {
768   RegStorage tmp = rs_x0;
769   LoadWordDisp(rs_xSELF, Thread::ThreadSuspendTriggerOffset<8>().Int32Value(), tmp);
770   LIR* load2 = LoadWordDisp(tmp, 0, tmp);
771   return load2;
772 }
773 
GetTargetInstFlags(int opcode)774 uint64_t Arm64Mir2Lir::GetTargetInstFlags(int opcode) {
775   DCHECK(!IsPseudoLirOp(opcode));
776   return Arm64Mir2Lir::EncodingMap[UNWIDE(opcode)].flags;
777 }
778 
GetTargetInstName(int opcode)779 const char* Arm64Mir2Lir::GetTargetInstName(int opcode) {
780   DCHECK(!IsPseudoLirOp(opcode));
781   return Arm64Mir2Lir::EncodingMap[UNWIDE(opcode)].name;
782 }
783 
GetTargetInstFmt(int opcode)784 const char* Arm64Mir2Lir::GetTargetInstFmt(int opcode) {
785   DCHECK(!IsPseudoLirOp(opcode));
786   return Arm64Mir2Lir::EncodingMap[UNWIDE(opcode)].fmt;
787 }
788 
GetNextReg(bool is_double_or_float,bool is_wide,bool is_ref)789 RegStorage Arm64Mir2Lir::InToRegStorageArm64Mapper::GetNextReg(bool is_double_or_float,
790                                                                bool is_wide,
791                                                                bool is_ref) {
792   const RegStorage coreArgMappingToPhysicalReg[] =
793       {rs_x1, rs_x2, rs_x3, rs_x4, rs_x5, rs_x6, rs_x7};
794   const int coreArgMappingToPhysicalRegSize =
795       sizeof(coreArgMappingToPhysicalReg) / sizeof(RegStorage);
796   const RegStorage fpArgMappingToPhysicalReg[] =
797       {rs_f0, rs_f1, rs_f2, rs_f3, rs_f4, rs_f5, rs_f6, rs_f7};
798   const int fpArgMappingToPhysicalRegSize =
799       sizeof(fpArgMappingToPhysicalReg) / sizeof(RegStorage);
800 
801   RegStorage result = RegStorage::InvalidReg();
802   if (is_double_or_float) {
803     if (cur_fp_reg_ < fpArgMappingToPhysicalRegSize) {
804       DCHECK(!is_ref);
805       result = fpArgMappingToPhysicalReg[cur_fp_reg_++];
806       if (result.Valid()) {
807         // TODO: switching between widths remains a bit ugly.  Better way?
808         int res_reg = result.GetReg();
809         result = is_wide ? RegStorage::FloatSolo64(res_reg) : RegStorage::FloatSolo32(res_reg);
810       }
811     }
812   } else {
813     if (cur_core_reg_ < coreArgMappingToPhysicalRegSize) {
814       result = coreArgMappingToPhysicalReg[cur_core_reg_++];
815       if (result.Valid()) {
816         // TODO: switching between widths remains a bit ugly.  Better way?
817         int res_reg = result.GetReg();
818         DCHECK(!(is_wide && is_ref));
819         result = (is_wide || is_ref) ? RegStorage::Solo64(res_reg) : RegStorage::Solo32(res_reg);
820       }
821     }
822   }
823   return result;
824 }
825 
Get(int in_position)826 RegStorage Arm64Mir2Lir::InToRegStorageMapping::Get(int in_position) {
827   DCHECK(IsInitialized());
828   auto res = mapping_.find(in_position);
829   return res != mapping_.end() ? res->second : RegStorage::InvalidReg();
830 }
831 
Initialize(RegLocation * arg_locs,int count,InToRegStorageMapper * mapper)832 void Arm64Mir2Lir::InToRegStorageMapping::Initialize(RegLocation* arg_locs, int count,
833                                                      InToRegStorageMapper* mapper) {
834   DCHECK(mapper != nullptr);
835   max_mapped_in_ = -1;
836   is_there_stack_mapped_ = false;
837   for (int in_position = 0; in_position < count; in_position++) {
838      RegStorage reg = mapper->GetNextReg(arg_locs[in_position].fp,
839                                          arg_locs[in_position].wide,
840                                          arg_locs[in_position].ref);
841      if (reg.Valid()) {
842        mapping_[in_position] = reg;
843        if (arg_locs[in_position].wide) {
844          // We covered 2 args, so skip the next one
845          in_position++;
846        }
847        max_mapped_in_ = std::max(max_mapped_in_, in_position);
848      } else {
849        is_there_stack_mapped_ = true;
850      }
851   }
852   initialized_ = true;
853 }
854 
855 
856 // Deprecate.  Use the new mechanism.
857 // TODO(Arm64): reuse info in QuickArgumentVisitor?
GetArgPhysicalReg(RegLocation * loc,int * num_gpr_used,int * num_fpr_used,OpSize * op_size)858 static RegStorage GetArgPhysicalReg(RegLocation* loc, int* num_gpr_used, int* num_fpr_used,
859                                     OpSize* op_size) {
860   if (loc->fp) {
861     int n = *num_fpr_used;
862     if (n < 8) {
863       *num_fpr_used = n + 1;
864       RegStorage::RegStorageKind reg_kind;
865       if (loc->wide) {
866         *op_size = kDouble;
867         reg_kind = RegStorage::k64BitSolo;
868       } else {
869         *op_size = kSingle;
870         reg_kind = RegStorage::k32BitSolo;
871       }
872       return RegStorage(RegStorage::kValid | reg_kind | RegStorage::kFloatingPoint | n);
873     }
874   } else {
875     int n = *num_gpr_used;
876     if (n < 8) {
877       *num_gpr_used = n + 1;
878       if (loc->wide || loc->ref) {
879         *op_size = k64;
880         return RegStorage::Solo64(n);
881       } else {
882         *op_size = k32;
883         return RegStorage::Solo32(n);
884       }
885     }
886   }
887   *op_size = kWord;
888   return RegStorage::InvalidReg();
889 }
890 
GetArgMappingToPhysicalReg(int arg_num)891 RegStorage Arm64Mir2Lir::GetArgMappingToPhysicalReg(int arg_num) {
892   if (!in_to_reg_storage_mapping_.IsInitialized()) {
893     int start_vreg = cu_->num_dalvik_registers - cu_->num_ins;
894     RegLocation* arg_locs = &mir_graph_->reg_location_[start_vreg];
895 
896     InToRegStorageArm64Mapper mapper;
897     in_to_reg_storage_mapping_.Initialize(arg_locs, cu_->num_ins, &mapper);
898   }
899   return in_to_reg_storage_mapping_.Get(arg_num);
900 }
901 
902 
903 /*
904  * If there are any ins passed in registers that have not been promoted
905  * to a callee-save register, flush them to the frame.  Perform initial
906  * assignment of promoted arguments.
907  *
908  * ArgLocs is an array of location records describing the incoming arguments
909  * with one location record per word of argument.
910  */
FlushIns(RegLocation * ArgLocs,RegLocation rl_method)911 void Arm64Mir2Lir::FlushIns(RegLocation* ArgLocs, RegLocation rl_method) {
912   int num_gpr_used = 1;
913   int num_fpr_used = 0;
914 
915   /*
916    * Dummy up a RegLocation for the incoming StackReference<mirror::ArtMethod>
917    * It will attempt to keep kArg0 live (or copy it to home location
918    * if promoted).
919    */
920   RegLocation rl_src = rl_method;
921   rl_src.location = kLocPhysReg;
922   rl_src.reg = TargetReg(kArg0, kRef);
923   rl_src.home = false;
924   MarkLive(rl_src);
925   StoreValue(rl_method, rl_src);
926   // If Method* has been promoted, explicitly flush
927   if (rl_method.location == kLocPhysReg) {
928     StoreRefDisp(TargetPtrReg(kSp), 0, rl_src.reg, kNotVolatile);
929   }
930 
931   if (cu_->num_ins == 0) {
932     return;
933   }
934 
935   // Handle dalvik registers.
936   ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
937   int start_vreg = cu_->num_dalvik_registers - cu_->num_ins;
938   for (int i = 0; i < cu_->num_ins; i++) {
939     RegLocation* t_loc = &ArgLocs[i];
940     OpSize op_size;
941     RegStorage reg = GetArgPhysicalReg(t_loc, &num_gpr_used, &num_fpr_used, &op_size);
942 
943     if (reg.Valid()) {
944       // If arriving in register.
945 
946       // We have already updated the arg location with promoted info
947       // so we can be based on it.
948       if (t_loc->location == kLocPhysReg) {
949         // Just copy it.
950         OpRegCopy(t_loc->reg, reg);
951       } else {
952         // Needs flush.
953         if (t_loc->ref) {
954           StoreRefDisp(TargetPtrReg(kSp), SRegOffset(start_vreg + i), reg, kNotVolatile);
955         } else {
956           StoreBaseDisp(TargetPtrReg(kSp), SRegOffset(start_vreg + i), reg, t_loc->wide ? k64 : k32,
957               kNotVolatile);
958         }
959       }
960     } else {
961       // If arriving in frame & promoted.
962       if (t_loc->location == kLocPhysReg) {
963         if (t_loc->ref) {
964           LoadRefDisp(TargetPtrReg(kSp), SRegOffset(start_vreg + i), t_loc->reg, kNotVolatile);
965         } else {
966           LoadBaseDisp(TargetPtrReg(kSp), SRegOffset(start_vreg + i), t_loc->reg,
967                        t_loc->wide ? k64 : k32, kNotVolatile);
968         }
969       }
970     }
971     if (t_loc->wide) {
972       // Increment i to skip the next one.
973       i++;
974     }
975     //      if ((v_map->core_location == kLocPhysReg) && !t_loc->fp) {
976     //        OpRegCopy(RegStorage::Solo32(v_map->core_reg), reg);
977     //      } else if ((v_map->fp_location == kLocPhysReg) && t_loc->fp) {
978     //        OpRegCopy(RegStorage::Solo32(v_map->fp_reg), reg);
979     //      } else {
980     //        StoreBaseDisp(TargetReg(kSp), SRegOffset(start_vreg + i), reg, op_size, kNotVolatile);
981     //        if (reg.Is64Bit()) {
982     //          if (SRegOffset(start_vreg + i) + 4 != SRegOffset(start_vreg + i + 1)) {
983     //            LOG(FATAL) << "64 bit value stored in non-consecutive 4 bytes slots";
984     //          }
985     //          i += 1;
986     //        }
987     //      }
988     //    } else {
989     //      // If arriving in frame & promoted
990     //      if (v_map->core_location == kLocPhysReg) {
991     //        LoadWordDisp(TargetReg(kSp), SRegOffset(start_vreg + i),
992     //                     RegStorage::Solo32(v_map->core_reg));
993     //      }
994     //      if (v_map->fp_location == kLocPhysReg) {
995     //        LoadWordDisp(TargetReg(kSp), SRegOffset(start_vreg + i), RegStorage::Solo32(v_map->fp_reg));
996     //      }
997   }
998 }
999 
1000 /*
1001  * Load up to 5 arguments, the first three of which will be in
1002  * kArg1 .. kArg3.  On entry kArg0 contains the current method pointer,
1003  * and as part of the load sequence, it must be replaced with
1004  * the target method pointer.
1005  */
GenDalvikArgsNoRange(CallInfo * info,int call_state,LIR ** pcrLabel,NextCallInsn next_call_insn,const MethodReference & target_method,uint32_t vtable_idx,uintptr_t direct_code,uintptr_t direct_method,InvokeType type,bool skip_this)1006 int Arm64Mir2Lir::GenDalvikArgsNoRange(CallInfo* info,
1007                                        int call_state, LIR** pcrLabel, NextCallInsn next_call_insn,
1008                                        const MethodReference& target_method,
1009                                        uint32_t vtable_idx, uintptr_t direct_code,
1010                                        uintptr_t direct_method, InvokeType type, bool skip_this) {
1011   return GenDalvikArgsRange(info,
1012                        call_state, pcrLabel, next_call_insn,
1013                        target_method,
1014                        vtable_idx, direct_code,
1015                        direct_method, type, skip_this);
1016 }
1017 
1018 /*
1019  * May have 0+ arguments (also used for jumbo).  Note that
1020  * source virtual registers may be in physical registers, so may
1021  * need to be flushed to home location before copying.  This
1022  * applies to arg3 and above (see below).
1023  *
1024  * FIXME: update comments.
1025  *
1026  * Two general strategies:
1027  *    If < 20 arguments
1028  *       Pass args 3-18 using vldm/vstm block copy
1029  *       Pass arg0, arg1 & arg2 in kArg1-kArg3
1030  *    If 20+ arguments
1031  *       Pass args arg19+ using memcpy block copy
1032  *       Pass arg0, arg1 & arg2 in kArg1-kArg3
1033  *
1034  */
GenDalvikArgsRange(CallInfo * info,int call_state,LIR ** pcrLabel,NextCallInsn next_call_insn,const MethodReference & target_method,uint32_t vtable_idx,uintptr_t direct_code,uintptr_t direct_method,InvokeType type,bool skip_this)1035 int Arm64Mir2Lir::GenDalvikArgsRange(CallInfo* info, int call_state,
1036                                      LIR** pcrLabel, NextCallInsn next_call_insn,
1037                                      const MethodReference& target_method,
1038                                      uint32_t vtable_idx, uintptr_t direct_code,
1039                                      uintptr_t direct_method, InvokeType type, bool skip_this) {
1040   /* If no arguments, just return */
1041   if (info->num_arg_words == 0)
1042     return call_state;
1043 
1044   const int start_index = skip_this ? 1 : 0;
1045 
1046   InToRegStorageArm64Mapper mapper;
1047   InToRegStorageMapping in_to_reg_storage_mapping;
1048   in_to_reg_storage_mapping.Initialize(info->args, info->num_arg_words, &mapper);
1049   const int last_mapped_in = in_to_reg_storage_mapping.GetMaxMappedIn();
1050   int regs_left_to_pass_via_stack = info->num_arg_words - (last_mapped_in + 1);
1051 
1052   // First of all, check whether it makes sense to use bulk copying.
1053   // Bulk copying is done only for the range case.
1054   // TODO: make a constant instead of 2
1055   if (info->is_range && regs_left_to_pass_via_stack >= 2) {
1056     // Scan the rest of the args - if in phys_reg flush to memory
1057     for (int next_arg = last_mapped_in + 1; next_arg < info->num_arg_words;) {
1058       RegLocation loc = info->args[next_arg];
1059       if (loc.wide) {
1060         loc = UpdateLocWide(loc);
1061         if (loc.location == kLocPhysReg) {
1062           ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
1063           StoreBaseDisp(TargetPtrReg(kSp), SRegOffset(loc.s_reg_low), loc.reg, k64, kNotVolatile);
1064         }
1065         next_arg += 2;
1066       } else {
1067         loc = UpdateLoc(loc);
1068         if (loc.location == kLocPhysReg) {
1069           ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
1070           if (loc.ref) {
1071             StoreRefDisp(TargetPtrReg(kSp), SRegOffset(loc.s_reg_low), loc.reg, kNotVolatile);
1072           } else {
1073             StoreBaseDisp(TargetPtrReg(kSp), SRegOffset(loc.s_reg_low), loc.reg, k32,
1074                           kNotVolatile);
1075           }
1076         }
1077         next_arg++;
1078       }
1079     }
1080 
1081     // Logic below assumes that Method pointer is at offset zero from SP.
1082     DCHECK_EQ(VRegOffset(static_cast<int>(kVRegMethodPtrBaseReg)), 0);
1083 
1084     // The rest can be copied together
1085     int start_offset = SRegOffset(info->args[last_mapped_in + 1].s_reg_low);
1086     int outs_offset = StackVisitor::GetOutVROffset(last_mapped_in + 1,
1087                                                    cu_->instruction_set);
1088 
1089     int current_src_offset = start_offset;
1090     int current_dest_offset = outs_offset;
1091 
1092     // Only davik regs are accessed in this loop; no next_call_insn() calls.
1093     ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
1094     while (regs_left_to_pass_via_stack > 0) {
1095       /*
1096        * TODO: Improve by adding block copy for large number of arguments.  This
1097        * should be done, if possible, as a target-depending helper.  For now, just
1098        * copy a Dalvik vreg at a time.
1099        */
1100       // Moving 32-bits via general purpose register.
1101       size_t bytes_to_move = sizeof(uint32_t);
1102 
1103       // Instead of allocating a new temp, simply reuse one of the registers being used
1104       // for argument passing.
1105       RegStorage temp = TargetReg(kArg3, kNotWide);
1106 
1107       // Now load the argument VR and store to the outs.
1108       Load32Disp(TargetPtrReg(kSp), current_src_offset, temp);
1109       Store32Disp(TargetPtrReg(kSp), current_dest_offset, temp);
1110 
1111       current_src_offset += bytes_to_move;
1112       current_dest_offset += bytes_to_move;
1113       regs_left_to_pass_via_stack -= (bytes_to_move >> 2);
1114     }
1115     DCHECK_EQ(regs_left_to_pass_via_stack, 0);
1116   }
1117 
1118   // Now handle rest not registers if they are
1119   if (in_to_reg_storage_mapping.IsThereStackMapped()) {
1120     RegStorage regWide = TargetReg(kArg3, kWide);
1121     for (int i = start_index; i <= last_mapped_in + regs_left_to_pass_via_stack; i++) {
1122       RegLocation rl_arg = info->args[i];
1123       rl_arg = UpdateRawLoc(rl_arg);
1124       RegStorage reg = in_to_reg_storage_mapping.Get(i);
1125       if (!reg.Valid()) {
1126         int out_offset = StackVisitor::GetOutVROffset(i, cu_->instruction_set);
1127 
1128         {
1129           ScopedMemRefType mem_ref_type(this, ResourceMask::kDalvikReg);
1130           if (rl_arg.wide) {
1131             if (rl_arg.location == kLocPhysReg) {
1132               StoreBaseDisp(TargetPtrReg(kSp), out_offset, rl_arg.reg, k64, kNotVolatile);
1133             } else {
1134               LoadValueDirectWideFixed(rl_arg, regWide);
1135               StoreBaseDisp(TargetPtrReg(kSp), out_offset, regWide, k64, kNotVolatile);
1136             }
1137           } else {
1138             if (rl_arg.location == kLocPhysReg) {
1139               if (rl_arg.ref) {
1140                 StoreRefDisp(TargetPtrReg(kSp), out_offset, rl_arg.reg, kNotVolatile);
1141               } else {
1142                 StoreBaseDisp(TargetPtrReg(kSp), out_offset, rl_arg.reg, k32, kNotVolatile);
1143               }
1144             } else {
1145               if (rl_arg.ref) {
1146                 RegStorage regSingle = TargetReg(kArg2, kRef);
1147                 LoadValueDirectFixed(rl_arg, regSingle);
1148                 StoreRefDisp(TargetPtrReg(kSp), out_offset, regSingle, kNotVolatile);
1149               } else {
1150                 RegStorage regSingle = TargetReg(kArg2, kNotWide);
1151                 LoadValueDirectFixed(rl_arg, regSingle);
1152                 StoreBaseDisp(TargetPtrReg(kSp), out_offset, regSingle, k32, kNotVolatile);
1153               }
1154             }
1155           }
1156         }
1157         call_state = next_call_insn(cu_, info, call_state, target_method,
1158                                     vtable_idx, direct_code, direct_method, type);
1159       }
1160       if (rl_arg.wide) {
1161         i++;
1162       }
1163     }
1164   }
1165 
1166   // Finish with mapped registers
1167   for (int i = start_index; i <= last_mapped_in; i++) {
1168     RegLocation rl_arg = info->args[i];
1169     rl_arg = UpdateRawLoc(rl_arg);
1170     RegStorage reg = in_to_reg_storage_mapping.Get(i);
1171     if (reg.Valid()) {
1172       if (rl_arg.wide) {
1173         LoadValueDirectWideFixed(rl_arg, reg);
1174       } else {
1175         LoadValueDirectFixed(rl_arg, reg);
1176       }
1177       call_state = next_call_insn(cu_, info, call_state, target_method, vtable_idx,
1178                                   direct_code, direct_method, type);
1179     }
1180     if (rl_arg.wide) {
1181       i++;
1182     }
1183   }
1184 
1185   call_state = next_call_insn(cu_, info, call_state, target_method, vtable_idx,
1186                            direct_code, direct_method, type);
1187   if (pcrLabel) {
1188     if (!cu_->compiler_driver->GetCompilerOptions().GetImplicitNullChecks()) {
1189       *pcrLabel = GenExplicitNullCheck(TargetReg(kArg1, kRef), info->opt_flags);
1190     } else {
1191       *pcrLabel = nullptr;
1192       // In lieu of generating a check for kArg1 being null, we need to
1193       // perform a load when doing implicit checks.
1194       RegStorage tmp = AllocTemp();
1195       Load32Disp(TargetReg(kArg1, kRef), 0, tmp);
1196       MarkPossibleNullPointerException(info->opt_flags);
1197       FreeTemp(tmp);
1198     }
1199   }
1200   return call_state;
1201 }
1202 
1203 }  // namespace art
1204