xref: /freebsd/contrib/llvm-project/libunwind/src/DwarfInstructions.hpp (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 //===-------------------------- DwarfInstructions.hpp ---------------------===//
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 //  Processor specific interpretation of DWARF unwind info.
9 //
10 //===----------------------------------------------------------------------===//
11 
12 #ifndef __DWARF_INSTRUCTIONS_HPP__
13 #define __DWARF_INSTRUCTIONS_HPP__
14 
15 #include <stdint.h>
16 #include <stdio.h>
17 #include <stdlib.h>
18 
19 #include "dwarf2.h"
20 #include "Registers.hpp"
21 #include "DwarfParser.hpp"
22 #include "config.h"
23 
24 
25 namespace libunwind {
26 
27 
28 /// DwarfInstructions maps abtract DWARF unwind instructions to a particular
29 /// architecture
30 template <typename A, typename R>
31 class DwarfInstructions {
32 public:
33   typedef typename A::pint_t pint_t;
34   typedef typename A::sint_t sint_t;
35 
36   static int stepWithDwarf(A &addressSpace, pint_t pc, pint_t fdeStart,
37                            R &registers, bool &isSignalFrame);
38 
39 private:
40 
41   enum {
42     DW_X86_64_RET_ADDR = 16
43   };
44 
45   enum {
46     DW_X86_RET_ADDR = 8
47   };
48 
49   typedef typename CFI_Parser<A>::RegisterLocation  RegisterLocation;
50   typedef typename CFI_Parser<A>::PrologInfo        PrologInfo;
51   typedef typename CFI_Parser<A>::FDE_Info          FDE_Info;
52   typedef typename CFI_Parser<A>::CIE_Info          CIE_Info;
53 
54   static pint_t evaluateExpression(pint_t expression, A &addressSpace,
55                                    const R &registers,
56                                    pint_t initialStackValue);
57   static pint_t getSavedRegister(A &addressSpace, const R &registers,
58                                  pint_t cfa, const RegisterLocation &savedReg);
59   static double getSavedFloatRegister(A &addressSpace, const R &registers,
60                                   pint_t cfa, const RegisterLocation &savedReg);
61   static v128 getSavedVectorRegister(A &addressSpace, const R &registers,
62                                   pint_t cfa, const RegisterLocation &savedReg);
63 
64   static pint_t getCFA(A &addressSpace, const PrologInfo &prolog,
65                        const R &registers) {
66     if (prolog.cfaRegister != 0)
67       return (pint_t)((sint_t)registers.getRegister((int)prolog.cfaRegister) +
68              prolog.cfaRegisterOffset);
69     if (prolog.cfaExpression != 0)
70       return evaluateExpression((pint_t)prolog.cfaExpression, addressSpace,
71                                 registers, 0);
72     assert(0 && "getCFA(): unknown location");
73     __builtin_unreachable();
74   }
75 };
76 
77 
78 template <typename A, typename R>
79 typename A::pint_t DwarfInstructions<A, R>::getSavedRegister(
80     A &addressSpace, const R &registers, pint_t cfa,
81     const RegisterLocation &savedReg) {
82   switch (savedReg.location) {
83   case CFI_Parser<A>::kRegisterInCFA:
84     return (pint_t)addressSpace.getRegister(cfa + (pint_t)savedReg.value);
85 
86   case CFI_Parser<A>::kRegisterAtExpression:
87     return (pint_t)addressSpace.getRegister(evaluateExpression(
88         (pint_t)savedReg.value, addressSpace, registers, cfa));
89 
90   case CFI_Parser<A>::kRegisterIsExpression:
91     return evaluateExpression((pint_t)savedReg.value, addressSpace,
92                               registers, cfa);
93 
94   case CFI_Parser<A>::kRegisterInRegister:
95     return registers.getRegister((int)savedReg.value);
96 
97   case CFI_Parser<A>::kRegisterUnused:
98   case CFI_Parser<A>::kRegisterOffsetFromCFA:
99     // FIX ME
100     break;
101   }
102   _LIBUNWIND_ABORT("unsupported restore location for register");
103 }
104 
105 template <typename A, typename R>
106 double DwarfInstructions<A, R>::getSavedFloatRegister(
107     A &addressSpace, const R &registers, pint_t cfa,
108     const RegisterLocation &savedReg) {
109   switch (savedReg.location) {
110   case CFI_Parser<A>::kRegisterInCFA:
111     return addressSpace.getDouble(cfa + (pint_t)savedReg.value);
112 
113   case CFI_Parser<A>::kRegisterAtExpression:
114     return addressSpace.getDouble(
115         evaluateExpression((pint_t)savedReg.value, addressSpace,
116                             registers, cfa));
117 
118   case CFI_Parser<A>::kRegisterIsExpression:
119   case CFI_Parser<A>::kRegisterUnused:
120   case CFI_Parser<A>::kRegisterOffsetFromCFA:
121   case CFI_Parser<A>::kRegisterInRegister:
122     // FIX ME
123     break;
124   }
125   _LIBUNWIND_ABORT("unsupported restore location for float register");
126 }
127 
128 template <typename A, typename R>
129 v128 DwarfInstructions<A, R>::getSavedVectorRegister(
130     A &addressSpace, const R &registers, pint_t cfa,
131     const RegisterLocation &savedReg) {
132   switch (savedReg.location) {
133   case CFI_Parser<A>::kRegisterInCFA:
134     return addressSpace.getVector(cfa + (pint_t)savedReg.value);
135 
136   case CFI_Parser<A>::kRegisterAtExpression:
137     return addressSpace.getVector(
138         evaluateExpression((pint_t)savedReg.value, addressSpace,
139                             registers, cfa));
140 
141   case CFI_Parser<A>::kRegisterIsExpression:
142   case CFI_Parser<A>::kRegisterUnused:
143   case CFI_Parser<A>::kRegisterOffsetFromCFA:
144   case CFI_Parser<A>::kRegisterInRegister:
145     // FIX ME
146     break;
147   }
148   _LIBUNWIND_ABORT("unsupported restore location for vector register");
149 }
150 
151 template <typename A, typename R>
152 int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
153                                            pint_t fdeStart, R &registers,
154                                            bool &isSignalFrame) {
155   FDE_Info fdeInfo;
156   CIE_Info cieInfo;
157   if (CFI_Parser<A>::decodeFDE(addressSpace, fdeStart, &fdeInfo,
158                                &cieInfo) == NULL) {
159     PrologInfo prolog;
160     if (CFI_Parser<A>::parseFDEInstructions(addressSpace, fdeInfo, cieInfo, pc,
161                                             R::getArch(), &prolog)) {
162       // get pointer to cfa (architecture specific)
163       pint_t cfa = getCFA(addressSpace, prolog, registers);
164 
165        // restore registers that DWARF says were saved
166       R newRegisters = registers;
167       pint_t returnAddress = 0;
168       const int lastReg = R::lastDwarfRegNum();
169       assert(static_cast<int>(CFI_Parser<A>::kMaxRegisterNumber) >= lastReg &&
170              "register range too large");
171       assert(lastReg >= (int)cieInfo.returnAddressRegister &&
172              "register range does not contain return address register");
173       for (int i = 0; i <= lastReg; ++i) {
174         if (prolog.savedRegisters[i].location !=
175             CFI_Parser<A>::kRegisterUnused) {
176           if (registers.validFloatRegister(i))
177             newRegisters.setFloatRegister(
178                 i, getSavedFloatRegister(addressSpace, registers, cfa,
179                                          prolog.savedRegisters[i]));
180           else if (registers.validVectorRegister(i))
181             newRegisters.setVectorRegister(
182                 i, getSavedVectorRegister(addressSpace, registers, cfa,
183                                           prolog.savedRegisters[i]));
184           else if (i == (int)cieInfo.returnAddressRegister)
185             returnAddress = getSavedRegister(addressSpace, registers, cfa,
186                                              prolog.savedRegisters[i]);
187           else if (registers.validRegister(i))
188             newRegisters.setRegister(
189                 i, getSavedRegister(addressSpace, registers, cfa,
190                                     prolog.savedRegisters[i]));
191           else
192             return UNW_EBADREG;
193         }
194       }
195 
196       // By definition, the CFA is the stack pointer at the call site, so
197       // restoring SP means setting it to CFA.
198       newRegisters.setSP(cfa);
199 
200       isSignalFrame = cieInfo.isSignalFrame;
201 
202 #if defined(_LIBUNWIND_TARGET_AARCH64)
203       // If the target is aarch64 then the return address may have been signed
204       // using the v8.3 pointer authentication extensions. The original
205       // return address needs to be authenticated before the return address is
206       // restored. autia1716 is used instead of autia as autia1716 assembles
207       // to a NOP on pre-v8.3a architectures.
208       if ((R::getArch() == REGISTERS_ARM64) &&
209           prolog.savedRegisters[UNW_ARM64_RA_SIGN_STATE].value) {
210 #if !defined(_LIBUNWIND_IS_NATIVE_ONLY)
211         return UNW_ECROSSRASIGNING;
212 #else
213         register unsigned long long x17 __asm("x17") = returnAddress;
214         register unsigned long long x16 __asm("x16") = cfa;
215 
216         // These are the autia1716/autib1716 instructions. The hint instructions
217         // are used here as gcc does not assemble autia1716/autib1716 for pre
218         // armv8.3a targets.
219         if (cieInfo.addressesSignedWithBKey)
220           asm("hint 0xe" : "+r"(x17) : "r"(x16)); // autib1716
221         else
222           asm("hint 0xc" : "+r"(x17) : "r"(x16)); // autia1716
223         returnAddress = x17;
224 #endif
225       }
226 #endif
227 
228 #if defined(_LIBUNWIND_TARGET_SPARC)
229       if (R::getArch() == REGISTERS_SPARC) {
230         // Skip call site instruction and delay slot
231         returnAddress += 8;
232         // Skip unimp instruction if function returns a struct
233         if ((addressSpace.get32(returnAddress) & 0xC1C00000) == 0)
234           returnAddress += 4;
235       }
236 #endif
237 
238 #if defined(_LIBUNWIND_TARGET_PPC64)
239 #define PPC64_ELFV1_R2_LOAD_INST_ENCODING 0xe8410028u // ld r2,40(r1)
240 #define PPC64_ELFV1_R2_OFFSET 40
241 #define PPC64_ELFV2_R2_LOAD_INST_ENCODING 0xe8410018u // ld r2,24(r1)
242 #define PPC64_ELFV2_R2_OFFSET 24
243       // If the instruction at return address is a TOC (r2) restore,
244       // then r2 was saved and needs to be restored.
245       // ELFv2 ABI specifies that the TOC Pointer must be saved at SP + 24,
246       // while in ELFv1 ABI it is saved at SP + 40.
247       if (R::getArch() == REGISTERS_PPC64 && returnAddress != 0) {
248         pint_t sp = newRegisters.getRegister(UNW_REG_SP);
249         pint_t r2 = 0;
250         switch (addressSpace.get32(returnAddress)) {
251         case PPC64_ELFV1_R2_LOAD_INST_ENCODING:
252           r2 = addressSpace.get64(sp + PPC64_ELFV1_R2_OFFSET);
253           break;
254         case PPC64_ELFV2_R2_LOAD_INST_ENCODING:
255           r2 = addressSpace.get64(sp + PPC64_ELFV2_R2_OFFSET);
256           break;
257         }
258         if (r2)
259           newRegisters.setRegister(UNW_PPC64_R2, r2);
260       }
261 #endif
262 
263       // Return address is address after call site instruction, so setting IP to
264       // that does simualates a return.
265       newRegisters.setIP(returnAddress);
266 
267       // Simulate the step by replacing the register set with the new ones.
268       registers = newRegisters;
269 
270       return UNW_STEP_SUCCESS;
271     }
272   }
273   return UNW_EBADFRAME;
274 }
275 
276 template <typename A, typename R>
277 typename A::pint_t
278 DwarfInstructions<A, R>::evaluateExpression(pint_t expression, A &addressSpace,
279                                             const R &registers,
280                                             pint_t initialStackValue) {
281   const bool log = false;
282   pint_t p = expression;
283   pint_t expressionEnd = expression + 20; // temp, until len read
284   pint_t length = (pint_t)addressSpace.getULEB128(p, expressionEnd);
285   expressionEnd = p + length;
286   if (log)
287     fprintf(stderr, "evaluateExpression(): length=%" PRIu64 "\n",
288             (uint64_t)length);
289   pint_t stack[100];
290   pint_t *sp = stack;
291   *(++sp) = initialStackValue;
292 
293   while (p < expressionEnd) {
294     if (log) {
295       for (pint_t *t = sp; t > stack; --t) {
296         fprintf(stderr, "sp[] = 0x%" PRIx64 "\n", (uint64_t)(*t));
297       }
298     }
299     uint8_t opcode = addressSpace.get8(p++);
300     sint_t svalue, svalue2;
301     pint_t value;
302     uint32_t reg;
303     switch (opcode) {
304     case DW_OP_addr:
305       // push immediate address sized value
306       value = addressSpace.getP(p);
307       p += sizeof(pint_t);
308       *(++sp) = value;
309       if (log)
310         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
311       break;
312 
313     case DW_OP_deref:
314       // pop stack, dereference, push result
315       value = *sp--;
316       *(++sp) = addressSpace.getP(value);
317       if (log)
318         fprintf(stderr, "dereference 0x%" PRIx64 "\n", (uint64_t)value);
319       break;
320 
321     case DW_OP_const1u:
322       // push immediate 1 byte value
323       value = addressSpace.get8(p);
324       p += 1;
325       *(++sp) = value;
326       if (log)
327         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
328       break;
329 
330     case DW_OP_const1s:
331       // push immediate 1 byte signed value
332       svalue = (int8_t) addressSpace.get8(p);
333       p += 1;
334       *(++sp) = (pint_t)svalue;
335       if (log)
336         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
337       break;
338 
339     case DW_OP_const2u:
340       // push immediate 2 byte value
341       value = addressSpace.get16(p);
342       p += 2;
343       *(++sp) = value;
344       if (log)
345         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
346       break;
347 
348     case DW_OP_const2s:
349       // push immediate 2 byte signed value
350       svalue = (int16_t) addressSpace.get16(p);
351       p += 2;
352       *(++sp) = (pint_t)svalue;
353       if (log)
354         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
355       break;
356 
357     case DW_OP_const4u:
358       // push immediate 4 byte value
359       value = addressSpace.get32(p);
360       p += 4;
361       *(++sp) = value;
362       if (log)
363         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
364       break;
365 
366     case DW_OP_const4s:
367       // push immediate 4 byte signed value
368       svalue = (int32_t)addressSpace.get32(p);
369       p += 4;
370       *(++sp) = (pint_t)svalue;
371       if (log)
372         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
373       break;
374 
375     case DW_OP_const8u:
376       // push immediate 8 byte value
377       value = (pint_t)addressSpace.get64(p);
378       p += 8;
379       *(++sp) = value;
380       if (log)
381         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
382       break;
383 
384     case DW_OP_const8s:
385       // push immediate 8 byte signed value
386       value = (pint_t)addressSpace.get64(p);
387       p += 8;
388       *(++sp) = value;
389       if (log)
390         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
391       break;
392 
393     case DW_OP_constu:
394       // push immediate ULEB128 value
395       value = (pint_t)addressSpace.getULEB128(p, expressionEnd);
396       *(++sp) = value;
397       if (log)
398         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
399       break;
400 
401     case DW_OP_consts:
402       // push immediate SLEB128 value
403       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
404       *(++sp) = (pint_t)svalue;
405       if (log)
406         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
407       break;
408 
409     case DW_OP_dup:
410       // push top of stack
411       value = *sp;
412       *(++sp) = value;
413       if (log)
414         fprintf(stderr, "duplicate top of stack\n");
415       break;
416 
417     case DW_OP_drop:
418       // pop
419       --sp;
420       if (log)
421         fprintf(stderr, "pop top of stack\n");
422       break;
423 
424     case DW_OP_over:
425       // dup second
426       value = sp[-1];
427       *(++sp) = value;
428       if (log)
429         fprintf(stderr, "duplicate second in stack\n");
430       break;
431 
432     case DW_OP_pick:
433       // pick from
434       reg = addressSpace.get8(p);
435       p += 1;
436       value = sp[-(int)reg];
437       *(++sp) = value;
438       if (log)
439         fprintf(stderr, "duplicate %d in stack\n", reg);
440       break;
441 
442     case DW_OP_swap:
443       // swap top two
444       value = sp[0];
445       sp[0] = sp[-1];
446       sp[-1] = value;
447       if (log)
448         fprintf(stderr, "swap top of stack\n");
449       break;
450 
451     case DW_OP_rot:
452       // rotate top three
453       value = sp[0];
454       sp[0] = sp[-1];
455       sp[-1] = sp[-2];
456       sp[-2] = value;
457       if (log)
458         fprintf(stderr, "rotate top three of stack\n");
459       break;
460 
461     case DW_OP_xderef:
462       // pop stack, dereference, push result
463       value = *sp--;
464       *sp = *((pint_t*)value);
465       if (log)
466         fprintf(stderr, "x-dereference 0x%" PRIx64 "\n", (uint64_t)value);
467       break;
468 
469     case DW_OP_abs:
470       svalue = (sint_t)*sp;
471       if (svalue < 0)
472         *sp = (pint_t)(-svalue);
473       if (log)
474         fprintf(stderr, "abs\n");
475       break;
476 
477     case DW_OP_and:
478       value = *sp--;
479       *sp &= value;
480       if (log)
481         fprintf(stderr, "and\n");
482       break;
483 
484     case DW_OP_div:
485       svalue = (sint_t)(*sp--);
486       svalue2 = (sint_t)*sp;
487       *sp = (pint_t)(svalue2 / svalue);
488       if (log)
489         fprintf(stderr, "div\n");
490       break;
491 
492     case DW_OP_minus:
493       value = *sp--;
494       *sp = *sp - value;
495       if (log)
496         fprintf(stderr, "minus\n");
497       break;
498 
499     case DW_OP_mod:
500       svalue = (sint_t)(*sp--);
501       svalue2 = (sint_t)*sp;
502       *sp = (pint_t)(svalue2 % svalue);
503       if (log)
504         fprintf(stderr, "module\n");
505       break;
506 
507     case DW_OP_mul:
508       svalue = (sint_t)(*sp--);
509       svalue2 = (sint_t)*sp;
510       *sp = (pint_t)(svalue2 * svalue);
511       if (log)
512         fprintf(stderr, "mul\n");
513       break;
514 
515     case DW_OP_neg:
516       *sp = 0 - *sp;
517       if (log)
518         fprintf(stderr, "neg\n");
519       break;
520 
521     case DW_OP_not:
522       svalue = (sint_t)(*sp);
523       *sp = (pint_t)(~svalue);
524       if (log)
525         fprintf(stderr, "not\n");
526       break;
527 
528     case DW_OP_or:
529       value = *sp--;
530       *sp |= value;
531       if (log)
532         fprintf(stderr, "or\n");
533       break;
534 
535     case DW_OP_plus:
536       value = *sp--;
537       *sp += value;
538       if (log)
539         fprintf(stderr, "plus\n");
540       break;
541 
542     case DW_OP_plus_uconst:
543       // pop stack, add uelb128 constant, push result
544       *sp += static_cast<pint_t>(addressSpace.getULEB128(p, expressionEnd));
545       if (log)
546         fprintf(stderr, "add constant\n");
547       break;
548 
549     case DW_OP_shl:
550       value = *sp--;
551       *sp = *sp << value;
552       if (log)
553         fprintf(stderr, "shift left\n");
554       break;
555 
556     case DW_OP_shr:
557       value = *sp--;
558       *sp = *sp >> value;
559       if (log)
560         fprintf(stderr, "shift left\n");
561       break;
562 
563     case DW_OP_shra:
564       value = *sp--;
565       svalue = (sint_t)*sp;
566       *sp = (pint_t)(svalue >> value);
567       if (log)
568         fprintf(stderr, "shift left arithmetric\n");
569       break;
570 
571     case DW_OP_xor:
572       value = *sp--;
573       *sp ^= value;
574       if (log)
575         fprintf(stderr, "xor\n");
576       break;
577 
578     case DW_OP_skip:
579       svalue = (int16_t) addressSpace.get16(p);
580       p += 2;
581       p = (pint_t)((sint_t)p + svalue);
582       if (log)
583         fprintf(stderr, "skip %" PRIu64 "\n", (uint64_t)svalue);
584       break;
585 
586     case DW_OP_bra:
587       svalue = (int16_t) addressSpace.get16(p);
588       p += 2;
589       if (*sp--)
590         p = (pint_t)((sint_t)p + svalue);
591       if (log)
592         fprintf(stderr, "bra %" PRIu64 "\n", (uint64_t)svalue);
593       break;
594 
595     case DW_OP_eq:
596       value = *sp--;
597       *sp = (*sp == value);
598       if (log)
599         fprintf(stderr, "eq\n");
600       break;
601 
602     case DW_OP_ge:
603       value = *sp--;
604       *sp = (*sp >= value);
605       if (log)
606         fprintf(stderr, "ge\n");
607       break;
608 
609     case DW_OP_gt:
610       value = *sp--;
611       *sp = (*sp > value);
612       if (log)
613         fprintf(stderr, "gt\n");
614       break;
615 
616     case DW_OP_le:
617       value = *sp--;
618       *sp = (*sp <= value);
619       if (log)
620         fprintf(stderr, "le\n");
621       break;
622 
623     case DW_OP_lt:
624       value = *sp--;
625       *sp = (*sp < value);
626       if (log)
627         fprintf(stderr, "lt\n");
628       break;
629 
630     case DW_OP_ne:
631       value = *sp--;
632       *sp = (*sp != value);
633       if (log)
634         fprintf(stderr, "ne\n");
635       break;
636 
637     case DW_OP_lit0:
638     case DW_OP_lit1:
639     case DW_OP_lit2:
640     case DW_OP_lit3:
641     case DW_OP_lit4:
642     case DW_OP_lit5:
643     case DW_OP_lit6:
644     case DW_OP_lit7:
645     case DW_OP_lit8:
646     case DW_OP_lit9:
647     case DW_OP_lit10:
648     case DW_OP_lit11:
649     case DW_OP_lit12:
650     case DW_OP_lit13:
651     case DW_OP_lit14:
652     case DW_OP_lit15:
653     case DW_OP_lit16:
654     case DW_OP_lit17:
655     case DW_OP_lit18:
656     case DW_OP_lit19:
657     case DW_OP_lit20:
658     case DW_OP_lit21:
659     case DW_OP_lit22:
660     case DW_OP_lit23:
661     case DW_OP_lit24:
662     case DW_OP_lit25:
663     case DW_OP_lit26:
664     case DW_OP_lit27:
665     case DW_OP_lit28:
666     case DW_OP_lit29:
667     case DW_OP_lit30:
668     case DW_OP_lit31:
669       value = static_cast<pint_t>(opcode - DW_OP_lit0);
670       *(++sp) = value;
671       if (log)
672         fprintf(stderr, "push literal 0x%" PRIx64 "\n", (uint64_t)value);
673       break;
674 
675     case DW_OP_reg0:
676     case DW_OP_reg1:
677     case DW_OP_reg2:
678     case DW_OP_reg3:
679     case DW_OP_reg4:
680     case DW_OP_reg5:
681     case DW_OP_reg6:
682     case DW_OP_reg7:
683     case DW_OP_reg8:
684     case DW_OP_reg9:
685     case DW_OP_reg10:
686     case DW_OP_reg11:
687     case DW_OP_reg12:
688     case DW_OP_reg13:
689     case DW_OP_reg14:
690     case DW_OP_reg15:
691     case DW_OP_reg16:
692     case DW_OP_reg17:
693     case DW_OP_reg18:
694     case DW_OP_reg19:
695     case DW_OP_reg20:
696     case DW_OP_reg21:
697     case DW_OP_reg22:
698     case DW_OP_reg23:
699     case DW_OP_reg24:
700     case DW_OP_reg25:
701     case DW_OP_reg26:
702     case DW_OP_reg27:
703     case DW_OP_reg28:
704     case DW_OP_reg29:
705     case DW_OP_reg30:
706     case DW_OP_reg31:
707       reg = static_cast<uint32_t>(opcode - DW_OP_reg0);
708       *(++sp) = registers.getRegister((int)reg);
709       if (log)
710         fprintf(stderr, "push reg %d\n", reg);
711       break;
712 
713     case DW_OP_regx:
714       reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
715       *(++sp) = registers.getRegister((int)reg);
716       if (log)
717         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
718       break;
719 
720     case DW_OP_breg0:
721     case DW_OP_breg1:
722     case DW_OP_breg2:
723     case DW_OP_breg3:
724     case DW_OP_breg4:
725     case DW_OP_breg5:
726     case DW_OP_breg6:
727     case DW_OP_breg7:
728     case DW_OP_breg8:
729     case DW_OP_breg9:
730     case DW_OP_breg10:
731     case DW_OP_breg11:
732     case DW_OP_breg12:
733     case DW_OP_breg13:
734     case DW_OP_breg14:
735     case DW_OP_breg15:
736     case DW_OP_breg16:
737     case DW_OP_breg17:
738     case DW_OP_breg18:
739     case DW_OP_breg19:
740     case DW_OP_breg20:
741     case DW_OP_breg21:
742     case DW_OP_breg22:
743     case DW_OP_breg23:
744     case DW_OP_breg24:
745     case DW_OP_breg25:
746     case DW_OP_breg26:
747     case DW_OP_breg27:
748     case DW_OP_breg28:
749     case DW_OP_breg29:
750     case DW_OP_breg30:
751     case DW_OP_breg31:
752       reg = static_cast<uint32_t>(opcode - DW_OP_breg0);
753       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
754       svalue += static_cast<sint_t>(registers.getRegister((int)reg));
755       *(++sp) = (pint_t)(svalue);
756       if (log)
757         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
758       break;
759 
760     case DW_OP_bregx:
761       reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
762       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
763       svalue += static_cast<sint_t>(registers.getRegister((int)reg));
764       *(++sp) = (pint_t)(svalue);
765       if (log)
766         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
767       break;
768 
769     case DW_OP_fbreg:
770       _LIBUNWIND_ABORT("DW_OP_fbreg not implemented");
771       break;
772 
773     case DW_OP_piece:
774       _LIBUNWIND_ABORT("DW_OP_piece not implemented");
775       break;
776 
777     case DW_OP_deref_size:
778       // pop stack, dereference, push result
779       value = *sp--;
780       switch (addressSpace.get8(p++)) {
781       case 1:
782         value = addressSpace.get8(value);
783         break;
784       case 2:
785         value = addressSpace.get16(value);
786         break;
787       case 4:
788         value = addressSpace.get32(value);
789         break;
790       case 8:
791         value = (pint_t)addressSpace.get64(value);
792         break;
793       default:
794         _LIBUNWIND_ABORT("DW_OP_deref_size with bad size");
795       }
796       *(++sp) = value;
797       if (log)
798         fprintf(stderr, "sized dereference 0x%" PRIx64 "\n", (uint64_t)value);
799       break;
800 
801     case DW_OP_xderef_size:
802     case DW_OP_nop:
803     case DW_OP_push_object_addres:
804     case DW_OP_call2:
805     case DW_OP_call4:
806     case DW_OP_call_ref:
807     default:
808       _LIBUNWIND_ABORT("DWARF opcode not implemented");
809     }
810 
811   }
812   if (log)
813     fprintf(stderr, "expression evaluates to 0x%" PRIx64 "\n", (uint64_t)*sp);
814   return *sp;
815 }
816 
817 
818 
819 } // namespace libunwind
820 
821 #endif // __DWARF_INSTRUCTIONS_HPP__
822