1 //===----------------------------------------------------------------------===//
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 #if defined(_LIBUNWIND_TARGET_AARCH64)
76   static bool getRA_SIGN_STATE(A &addressSpace, R registers, pint_t cfa,
77                                PrologInfo &prolog);
78 #endif
79 };
80 
81 template <typename R>
82 auto getSparcWCookie(const R &r, int) -> decltype(r.getWCookie()) {
83   return r.getWCookie();
84 }
85 template <typename R> uint64_t getSparcWCookie(const R &, long) {
86   return 0;
87 }
88 
89 template <typename A, typename R>
90 typename A::pint_t DwarfInstructions<A, R>::getSavedRegister(
91     A &addressSpace, const R &registers, pint_t cfa,
92     const RegisterLocation &savedReg) {
93   switch (savedReg.location) {
94   case CFI_Parser<A>::kRegisterInCFA:
95     return (pint_t)addressSpace.getRegister(cfa + (pint_t)savedReg.value);
96 
97   case CFI_Parser<A>::kRegisterInCFADecrypt: // sparc64 specific
98     return (pint_t)(addressSpace.getP(cfa + (pint_t)savedReg.value) ^
99            getSparcWCookie(registers, 0));
100 
101   case CFI_Parser<A>::kRegisterAtExpression:
102     return (pint_t)addressSpace.getRegister(evaluateExpression(
103         (pint_t)savedReg.value, addressSpace, registers, cfa));
104 
105   case CFI_Parser<A>::kRegisterIsExpression:
106     return evaluateExpression((pint_t)savedReg.value, addressSpace,
107                               registers, cfa);
108 
109   case CFI_Parser<A>::kRegisterInRegister:
110     return registers.getRegister((int)savedReg.value);
111   case CFI_Parser<A>::kRegisterUndefined:
112     return 0;
113   case CFI_Parser<A>::kRegisterUnused:
114   case CFI_Parser<A>::kRegisterOffsetFromCFA:
115     // FIX ME
116     break;
117   }
118   _LIBUNWIND_ABORT("unsupported restore location for register");
119 }
120 
121 template <typename A, typename R>
122 double DwarfInstructions<A, R>::getSavedFloatRegister(
123     A &addressSpace, const R &registers, pint_t cfa,
124     const RegisterLocation &savedReg) {
125   switch (savedReg.location) {
126   case CFI_Parser<A>::kRegisterInCFA:
127     return addressSpace.getDouble(cfa + (pint_t)savedReg.value);
128 
129   case CFI_Parser<A>::kRegisterAtExpression:
130     return addressSpace.getDouble(
131         evaluateExpression((pint_t)savedReg.value, addressSpace,
132                             registers, cfa));
133   case CFI_Parser<A>::kRegisterUndefined:
134     return 0.0;
135   case CFI_Parser<A>::kRegisterInRegister:
136 #ifndef _LIBUNWIND_TARGET_ARM
137     return registers.getFloatRegister((int)savedReg.value);
138 #endif
139   case CFI_Parser<A>::kRegisterIsExpression:
140   case CFI_Parser<A>::kRegisterUnused:
141   case CFI_Parser<A>::kRegisterOffsetFromCFA:
142   case CFI_Parser<A>::kRegisterInCFADecrypt:
143     // FIX ME
144     break;
145   }
146   _LIBUNWIND_ABORT("unsupported restore location for float register");
147 }
148 
149 template <typename A, typename R>
150 v128 DwarfInstructions<A, R>::getSavedVectorRegister(
151     A &addressSpace, const R &registers, pint_t cfa,
152     const RegisterLocation &savedReg) {
153   switch (savedReg.location) {
154   case CFI_Parser<A>::kRegisterInCFA:
155     return addressSpace.getVector(cfa + (pint_t)savedReg.value);
156 
157   case CFI_Parser<A>::kRegisterAtExpression:
158     return addressSpace.getVector(
159         evaluateExpression((pint_t)savedReg.value, addressSpace,
160                             registers, cfa));
161 
162   case CFI_Parser<A>::kRegisterIsExpression:
163   case CFI_Parser<A>::kRegisterUnused:
164   case CFI_Parser<A>::kRegisterUndefined:
165   case CFI_Parser<A>::kRegisterOffsetFromCFA:
166   case CFI_Parser<A>::kRegisterInRegister:
167   case CFI_Parser<A>::kRegisterInCFADecrypt:
168     // FIX ME
169     break;
170   }
171   _LIBUNWIND_ABORT("unsupported restore location for vector register");
172 }
173 #if defined(_LIBUNWIND_TARGET_AARCH64)
174 template <typename A, typename R>
175 bool DwarfInstructions<A, R>::getRA_SIGN_STATE(A &addressSpace, R registers,
176                                                pint_t cfa, PrologInfo &prolog) {
177   pint_t raSignState;
178   auto regloc = prolog.savedRegisters[UNW_AARCH64_RA_SIGN_STATE];
179   if (regloc.location == CFI_Parser<A>::kRegisterUnused)
180     raSignState = static_cast<pint_t>(regloc.value);
181   else
182     raSignState = getSavedRegister(addressSpace, registers, cfa, regloc);
183 
184   // Only bit[0] is meaningful.
185   return raSignState & 0x01;
186 }
187 #endif
188 
189 template <typename A, typename R>
190 int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
191                                            pint_t fdeStart, R &registers,
192                                            bool &isSignalFrame) {
193   FDE_Info fdeInfo;
194   CIE_Info cieInfo;
195   if (CFI_Parser<A>::decodeFDE(addressSpace, fdeStart, &fdeInfo,
196                                &cieInfo) == NULL) {
197     PrologInfo prolog;
198     if (CFI_Parser<A>::parseFDEInstructions(addressSpace, fdeInfo, cieInfo, pc,
199                                             R::getArch(), &prolog)) {
200       // get pointer to cfa (architecture specific)
201       pint_t cfa = getCFA(addressSpace, prolog, registers);
202 
203        // restore registers that DWARF says were saved
204       R newRegisters = registers;
205 
206       // Typically, the CFA is the stack pointer at the call site in
207       // the previous frame. However, there are scenarios in which this is not
208       // true. For example, if we switched to a new stack. In that case, the
209       // value of the previous SP might be indicated by a CFI directive.
210       //
211       // We set the SP here to the CFA, allowing for it to be overridden
212       // by a CFI directive later on.
213       newRegisters.setSP(cfa);
214 
215       pint_t returnAddress = 0;
216       const int lastReg = R::lastDwarfRegNum();
217       assert(static_cast<int>(CFI_Parser<A>::kMaxRegisterNumber) >= lastReg &&
218              "register range too large");
219       assert(lastReg >= (int)cieInfo.returnAddressRegister &&
220              "register range does not contain return address register");
221       for (int i = 0; i <= lastReg; ++i) {
222         if (prolog.savedRegisters[i].location !=
223             CFI_Parser<A>::kRegisterUnused) {
224           if (registers.validFloatRegister(i))
225             newRegisters.setFloatRegister(
226                 i, getSavedFloatRegister(addressSpace, registers, cfa,
227                                          prolog.savedRegisters[i]));
228           else if (registers.validVectorRegister(i))
229             newRegisters.setVectorRegister(
230                 i, getSavedVectorRegister(addressSpace, registers, cfa,
231                                           prolog.savedRegisters[i]));
232           else if (i == (int)cieInfo.returnAddressRegister)
233             returnAddress = getSavedRegister(addressSpace, registers, cfa,
234                                              prolog.savedRegisters[i]);
235           else if (registers.validRegister(i))
236             newRegisters.setRegister(
237                 i, getSavedRegister(addressSpace, registers, cfa,
238                                     prolog.savedRegisters[i]));
239           else
240             return UNW_EBADREG;
241         } else if (i == (int)cieInfo.returnAddressRegister) {
242             // Leaf function keeps the return address in register and there is no
243             // explicit intructions how to restore it.
244             returnAddress = registers.getRegister(cieInfo.returnAddressRegister);
245         }
246       }
247 
248       isSignalFrame = cieInfo.isSignalFrame;
249 
250 #if defined(_LIBUNWIND_TARGET_AARCH64)
251       // If the target is aarch64 then the return address may have been signed
252       // using the v8.3 pointer authentication extensions. The original
253       // return address needs to be authenticated before the return address is
254       // restored. autia1716 is used instead of autia as autia1716 assembles
255       // to a NOP on pre-v8.3a architectures.
256       if ((R::getArch() == REGISTERS_ARM64) &&
257           getRA_SIGN_STATE(addressSpace, registers, cfa, prolog) &&
258           returnAddress != 0) {
259 #if !defined(_LIBUNWIND_IS_NATIVE_ONLY)
260         return UNW_ECROSSRASIGNING;
261 #else
262         register unsigned long long x17 __asm("x17") = returnAddress;
263         register unsigned long long x16 __asm("x16") = cfa;
264 
265         // These are the autia1716/autib1716 instructions. The hint instructions
266         // are used here as gcc does not assemble autia1716/autib1716 for pre
267         // armv8.3a targets.
268         if (cieInfo.addressesSignedWithBKey)
269           asm("hint 0xe" : "+r"(x17) : "r"(x16)); // autib1716
270         else
271           asm("hint 0xc" : "+r"(x17) : "r"(x16)); // autia1716
272         returnAddress = x17;
273 #endif
274       }
275 #endif
276 
277 #if defined(_LIBUNWIND_IS_NATIVE_ONLY) && defined(_LIBUNWIND_TARGET_ARM) &&    \
278     defined(__ARM_FEATURE_PAUTH)
279       if ((R::getArch() == REGISTERS_ARM) &&
280           prolog.savedRegisters[UNW_ARM_RA_AUTH_CODE].value) {
281         pint_t pac =
282             getSavedRegister(addressSpace, registers, cfa,
283                              prolog.savedRegisters[UNW_ARM_RA_AUTH_CODE]);
284         __asm__ __volatile__("autg %0, %1, %2"
285                              :
286                              : "r"(pac), "r"(returnAddress), "r"(cfa)
287                              :);
288       }
289 #endif
290 
291 #if defined(_LIBUNWIND_TARGET_SPARC)
292       if (R::getArch() == REGISTERS_SPARC) {
293         // Skip call site instruction and delay slot
294         returnAddress += 8;
295         // Skip unimp instruction if function returns a struct
296         if ((addressSpace.get32(returnAddress) & 0xC1C00000) == 0)
297           returnAddress += 4;
298       }
299 #endif
300 
301 #if defined(_LIBUNWIND_TARGET_SPARC64)
302       // Skip call site instruction and delay slot.
303       if (R::getArch() == REGISTERS_SPARC64)
304         returnAddress += 8;
305 #endif
306 
307 #if defined(_LIBUNWIND_TARGET_PPC64)
308 #define PPC64_ELFV1_R2_LOAD_INST_ENCODING 0xe8410028u // ld r2,40(r1)
309 #define PPC64_ELFV1_R2_OFFSET 40
310 #define PPC64_ELFV2_R2_LOAD_INST_ENCODING 0xe8410018u // ld r2,24(r1)
311 #define PPC64_ELFV2_R2_OFFSET 24
312       // If the instruction at return address is a TOC (r2) restore,
313       // then r2 was saved and needs to be restored.
314       // ELFv2 ABI specifies that the TOC Pointer must be saved at SP + 24,
315       // while in ELFv1 ABI it is saved at SP + 40.
316       if (R::getArch() == REGISTERS_PPC64 && returnAddress != 0) {
317         pint_t sp = newRegisters.getRegister(UNW_REG_SP);
318         pint_t r2 = 0;
319         switch (addressSpace.get32(returnAddress)) {
320         case PPC64_ELFV1_R2_LOAD_INST_ENCODING:
321           r2 = addressSpace.get64(sp + PPC64_ELFV1_R2_OFFSET);
322           break;
323         case PPC64_ELFV2_R2_LOAD_INST_ENCODING:
324           r2 = addressSpace.get64(sp + PPC64_ELFV2_R2_OFFSET);
325           break;
326         }
327         if (r2)
328           newRegisters.setRegister(UNW_PPC64_R2, r2);
329       }
330 #endif
331 
332       // Return address is address after call site instruction, so setting IP to
333       // that does simualates a return.
334       newRegisters.setIP(returnAddress);
335 
336       // Simulate the step by replacing the register set with the new ones.
337       registers = newRegisters;
338 
339       return UNW_STEP_SUCCESS;
340     }
341   }
342   return UNW_EBADFRAME;
343 }
344 
345 template <typename A, typename R>
346 typename A::pint_t
347 DwarfInstructions<A, R>::evaluateExpression(pint_t expression, A &addressSpace,
348                                             const R &registers,
349                                             pint_t initialStackValue) {
350   const bool log = false;
351   pint_t p = expression;
352   pint_t expressionEnd = expression + 20; // temp, until len read
353   pint_t length = (pint_t)addressSpace.getULEB128(p, expressionEnd);
354   expressionEnd = p + length;
355   if (log)
356     fprintf(stderr, "evaluateExpression(): length=%" PRIu64 "\n",
357             (uint64_t)length);
358   pint_t stack[100];
359   pint_t *sp = stack;
360   *(++sp) = initialStackValue;
361 
362   while (p < expressionEnd) {
363     if (log) {
364       for (pint_t *t = sp; t > stack; --t) {
365         fprintf(stderr, "sp[] = 0x%" PRIx64 "\n", (uint64_t)(*t));
366       }
367     }
368     uint8_t opcode = addressSpace.get8(p++);
369     sint_t svalue, svalue2;
370     pint_t value;
371     uint32_t reg;
372     switch (opcode) {
373     case DW_OP_addr:
374       // push immediate address sized value
375       value = addressSpace.getP(p);
376       p += sizeof(pint_t);
377       *(++sp) = value;
378       if (log)
379         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
380       break;
381 
382     case DW_OP_deref:
383       // pop stack, dereference, push result
384       value = *sp--;
385       *(++sp) = addressSpace.getP(value);
386       if (log)
387         fprintf(stderr, "dereference 0x%" PRIx64 "\n", (uint64_t)value);
388       break;
389 
390     case DW_OP_const1u:
391       // push immediate 1 byte value
392       value = addressSpace.get8(p);
393       p += 1;
394       *(++sp) = value;
395       if (log)
396         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
397       break;
398 
399     case DW_OP_const1s:
400       // push immediate 1 byte signed value
401       svalue = (int8_t) addressSpace.get8(p);
402       p += 1;
403       *(++sp) = (pint_t)svalue;
404       if (log)
405         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
406       break;
407 
408     case DW_OP_const2u:
409       // push immediate 2 byte value
410       value = addressSpace.get16(p);
411       p += 2;
412       *(++sp) = value;
413       if (log)
414         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
415       break;
416 
417     case DW_OP_const2s:
418       // push immediate 2 byte signed value
419       svalue = (int16_t) addressSpace.get16(p);
420       p += 2;
421       *(++sp) = (pint_t)svalue;
422       if (log)
423         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
424       break;
425 
426     case DW_OP_const4u:
427       // push immediate 4 byte value
428       value = addressSpace.get32(p);
429       p += 4;
430       *(++sp) = value;
431       if (log)
432         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
433       break;
434 
435     case DW_OP_const4s:
436       // push immediate 4 byte signed value
437       svalue = (int32_t)addressSpace.get32(p);
438       p += 4;
439       *(++sp) = (pint_t)svalue;
440       if (log)
441         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
442       break;
443 
444     case DW_OP_const8u:
445       // push immediate 8 byte value
446       value = (pint_t)addressSpace.get64(p);
447       p += 8;
448       *(++sp) = value;
449       if (log)
450         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
451       break;
452 
453     case DW_OP_const8s:
454       // push immediate 8 byte signed value
455       value = (pint_t)addressSpace.get64(p);
456       p += 8;
457       *(++sp) = value;
458       if (log)
459         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
460       break;
461 
462     case DW_OP_constu:
463       // push immediate ULEB128 value
464       value = (pint_t)addressSpace.getULEB128(p, expressionEnd);
465       *(++sp) = value;
466       if (log)
467         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
468       break;
469 
470     case DW_OP_consts:
471       // push immediate SLEB128 value
472       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
473       *(++sp) = (pint_t)svalue;
474       if (log)
475         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
476       break;
477 
478     case DW_OP_dup:
479       // push top of stack
480       value = *sp;
481       *(++sp) = value;
482       if (log)
483         fprintf(stderr, "duplicate top of stack\n");
484       break;
485 
486     case DW_OP_drop:
487       // pop
488       --sp;
489       if (log)
490         fprintf(stderr, "pop top of stack\n");
491       break;
492 
493     case DW_OP_over:
494       // dup second
495       value = sp[-1];
496       *(++sp) = value;
497       if (log)
498         fprintf(stderr, "duplicate second in stack\n");
499       break;
500 
501     case DW_OP_pick:
502       // pick from
503       reg = addressSpace.get8(p);
504       p += 1;
505       value = sp[-(int)reg];
506       *(++sp) = value;
507       if (log)
508         fprintf(stderr, "duplicate %d in stack\n", reg);
509       break;
510 
511     case DW_OP_swap:
512       // swap top two
513       value = sp[0];
514       sp[0] = sp[-1];
515       sp[-1] = value;
516       if (log)
517         fprintf(stderr, "swap top of stack\n");
518       break;
519 
520     case DW_OP_rot:
521       // rotate top three
522       value = sp[0];
523       sp[0] = sp[-1];
524       sp[-1] = sp[-2];
525       sp[-2] = value;
526       if (log)
527         fprintf(stderr, "rotate top three of stack\n");
528       break;
529 
530     case DW_OP_xderef:
531       // pop stack, dereference, push result
532       value = *sp--;
533       *sp = *((pint_t*)value);
534       if (log)
535         fprintf(stderr, "x-dereference 0x%" PRIx64 "\n", (uint64_t)value);
536       break;
537 
538     case DW_OP_abs:
539       svalue = (sint_t)*sp;
540       if (svalue < 0)
541         *sp = (pint_t)(-svalue);
542       if (log)
543         fprintf(stderr, "abs\n");
544       break;
545 
546     case DW_OP_and:
547       value = *sp--;
548       *sp &= value;
549       if (log)
550         fprintf(stderr, "and\n");
551       break;
552 
553     case DW_OP_div:
554       svalue = (sint_t)(*sp--);
555       svalue2 = (sint_t)*sp;
556       *sp = (pint_t)(svalue2 / svalue);
557       if (log)
558         fprintf(stderr, "div\n");
559       break;
560 
561     case DW_OP_minus:
562       value = *sp--;
563       *sp = *sp - value;
564       if (log)
565         fprintf(stderr, "minus\n");
566       break;
567 
568     case DW_OP_mod:
569       svalue = (sint_t)(*sp--);
570       svalue2 = (sint_t)*sp;
571       *sp = (pint_t)(svalue2 % svalue);
572       if (log)
573         fprintf(stderr, "module\n");
574       break;
575 
576     case DW_OP_mul:
577       svalue = (sint_t)(*sp--);
578       svalue2 = (sint_t)*sp;
579       *sp = (pint_t)(svalue2 * svalue);
580       if (log)
581         fprintf(stderr, "mul\n");
582       break;
583 
584     case DW_OP_neg:
585       *sp = 0 - *sp;
586       if (log)
587         fprintf(stderr, "neg\n");
588       break;
589 
590     case DW_OP_not:
591       svalue = (sint_t)(*sp);
592       *sp = (pint_t)(~svalue);
593       if (log)
594         fprintf(stderr, "not\n");
595       break;
596 
597     case DW_OP_or:
598       value = *sp--;
599       *sp |= value;
600       if (log)
601         fprintf(stderr, "or\n");
602       break;
603 
604     case DW_OP_plus:
605       value = *sp--;
606       *sp += value;
607       if (log)
608         fprintf(stderr, "plus\n");
609       break;
610 
611     case DW_OP_plus_uconst:
612       // pop stack, add uelb128 constant, push result
613       *sp += static_cast<pint_t>(addressSpace.getULEB128(p, expressionEnd));
614       if (log)
615         fprintf(stderr, "add constant\n");
616       break;
617 
618     case DW_OP_shl:
619       value = *sp--;
620       *sp = *sp << value;
621       if (log)
622         fprintf(stderr, "shift left\n");
623       break;
624 
625     case DW_OP_shr:
626       value = *sp--;
627       *sp = *sp >> value;
628       if (log)
629         fprintf(stderr, "shift left\n");
630       break;
631 
632     case DW_OP_shra:
633       value = *sp--;
634       svalue = (sint_t)*sp;
635       *sp = (pint_t)(svalue >> value);
636       if (log)
637         fprintf(stderr, "shift left arithmetric\n");
638       break;
639 
640     case DW_OP_xor:
641       value = *sp--;
642       *sp ^= value;
643       if (log)
644         fprintf(stderr, "xor\n");
645       break;
646 
647     case DW_OP_skip:
648       svalue = (int16_t) addressSpace.get16(p);
649       p += 2;
650       p = (pint_t)((sint_t)p + svalue);
651       if (log)
652         fprintf(stderr, "skip %" PRIu64 "\n", (uint64_t)svalue);
653       break;
654 
655     case DW_OP_bra:
656       svalue = (int16_t) addressSpace.get16(p);
657       p += 2;
658       if (*sp--)
659         p = (pint_t)((sint_t)p + svalue);
660       if (log)
661         fprintf(stderr, "bra %" PRIu64 "\n", (uint64_t)svalue);
662       break;
663 
664     case DW_OP_eq:
665       value = *sp--;
666       *sp = (*sp == value);
667       if (log)
668         fprintf(stderr, "eq\n");
669       break;
670 
671     case DW_OP_ge:
672       value = *sp--;
673       *sp = (*sp >= value);
674       if (log)
675         fprintf(stderr, "ge\n");
676       break;
677 
678     case DW_OP_gt:
679       value = *sp--;
680       *sp = (*sp > value);
681       if (log)
682         fprintf(stderr, "gt\n");
683       break;
684 
685     case DW_OP_le:
686       value = *sp--;
687       *sp = (*sp <= value);
688       if (log)
689         fprintf(stderr, "le\n");
690       break;
691 
692     case DW_OP_lt:
693       value = *sp--;
694       *sp = (*sp < value);
695       if (log)
696         fprintf(stderr, "lt\n");
697       break;
698 
699     case DW_OP_ne:
700       value = *sp--;
701       *sp = (*sp != value);
702       if (log)
703         fprintf(stderr, "ne\n");
704       break;
705 
706     case DW_OP_lit0:
707     case DW_OP_lit1:
708     case DW_OP_lit2:
709     case DW_OP_lit3:
710     case DW_OP_lit4:
711     case DW_OP_lit5:
712     case DW_OP_lit6:
713     case DW_OP_lit7:
714     case DW_OP_lit8:
715     case DW_OP_lit9:
716     case DW_OP_lit10:
717     case DW_OP_lit11:
718     case DW_OP_lit12:
719     case DW_OP_lit13:
720     case DW_OP_lit14:
721     case DW_OP_lit15:
722     case DW_OP_lit16:
723     case DW_OP_lit17:
724     case DW_OP_lit18:
725     case DW_OP_lit19:
726     case DW_OP_lit20:
727     case DW_OP_lit21:
728     case DW_OP_lit22:
729     case DW_OP_lit23:
730     case DW_OP_lit24:
731     case DW_OP_lit25:
732     case DW_OP_lit26:
733     case DW_OP_lit27:
734     case DW_OP_lit28:
735     case DW_OP_lit29:
736     case DW_OP_lit30:
737     case DW_OP_lit31:
738       value = static_cast<pint_t>(opcode - DW_OP_lit0);
739       *(++sp) = value;
740       if (log)
741         fprintf(stderr, "push literal 0x%" PRIx64 "\n", (uint64_t)value);
742       break;
743 
744     case DW_OP_reg0:
745     case DW_OP_reg1:
746     case DW_OP_reg2:
747     case DW_OP_reg3:
748     case DW_OP_reg4:
749     case DW_OP_reg5:
750     case DW_OP_reg6:
751     case DW_OP_reg7:
752     case DW_OP_reg8:
753     case DW_OP_reg9:
754     case DW_OP_reg10:
755     case DW_OP_reg11:
756     case DW_OP_reg12:
757     case DW_OP_reg13:
758     case DW_OP_reg14:
759     case DW_OP_reg15:
760     case DW_OP_reg16:
761     case DW_OP_reg17:
762     case DW_OP_reg18:
763     case DW_OP_reg19:
764     case DW_OP_reg20:
765     case DW_OP_reg21:
766     case DW_OP_reg22:
767     case DW_OP_reg23:
768     case DW_OP_reg24:
769     case DW_OP_reg25:
770     case DW_OP_reg26:
771     case DW_OP_reg27:
772     case DW_OP_reg28:
773     case DW_OP_reg29:
774     case DW_OP_reg30:
775     case DW_OP_reg31:
776       reg = static_cast<uint32_t>(opcode - DW_OP_reg0);
777       *(++sp) = registers.getRegister((int)reg);
778       if (log)
779         fprintf(stderr, "push reg %d\n", reg);
780       break;
781 
782     case DW_OP_regx:
783       reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
784       *(++sp) = registers.getRegister((int)reg);
785       if (log)
786         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
787       break;
788 
789     case DW_OP_breg0:
790     case DW_OP_breg1:
791     case DW_OP_breg2:
792     case DW_OP_breg3:
793     case DW_OP_breg4:
794     case DW_OP_breg5:
795     case DW_OP_breg6:
796     case DW_OP_breg7:
797     case DW_OP_breg8:
798     case DW_OP_breg9:
799     case DW_OP_breg10:
800     case DW_OP_breg11:
801     case DW_OP_breg12:
802     case DW_OP_breg13:
803     case DW_OP_breg14:
804     case DW_OP_breg15:
805     case DW_OP_breg16:
806     case DW_OP_breg17:
807     case DW_OP_breg18:
808     case DW_OP_breg19:
809     case DW_OP_breg20:
810     case DW_OP_breg21:
811     case DW_OP_breg22:
812     case DW_OP_breg23:
813     case DW_OP_breg24:
814     case DW_OP_breg25:
815     case DW_OP_breg26:
816     case DW_OP_breg27:
817     case DW_OP_breg28:
818     case DW_OP_breg29:
819     case DW_OP_breg30:
820     case DW_OP_breg31:
821       reg = static_cast<uint32_t>(opcode - DW_OP_breg0);
822       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
823       svalue += static_cast<sint_t>(registers.getRegister((int)reg));
824       *(++sp) = (pint_t)(svalue);
825       if (log)
826         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
827       break;
828 
829     case DW_OP_bregx:
830       reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
831       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
832       svalue += static_cast<sint_t>(registers.getRegister((int)reg));
833       *(++sp) = (pint_t)(svalue);
834       if (log)
835         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
836       break;
837 
838     case DW_OP_fbreg:
839       _LIBUNWIND_ABORT("DW_OP_fbreg not implemented");
840       break;
841 
842     case DW_OP_piece:
843       _LIBUNWIND_ABORT("DW_OP_piece not implemented");
844       break;
845 
846     case DW_OP_deref_size:
847       // pop stack, dereference, push result
848       value = *sp--;
849       switch (addressSpace.get8(p++)) {
850       case 1:
851         value = addressSpace.get8(value);
852         break;
853       case 2:
854         value = addressSpace.get16(value);
855         break;
856       case 4:
857         value = addressSpace.get32(value);
858         break;
859       case 8:
860         value = (pint_t)addressSpace.get64(value);
861         break;
862       default:
863         _LIBUNWIND_ABORT("DW_OP_deref_size with bad size");
864       }
865       *(++sp) = value;
866       if (log)
867         fprintf(stderr, "sized dereference 0x%" PRIx64 "\n", (uint64_t)value);
868       break;
869 
870     case DW_OP_xderef_size:
871     case DW_OP_nop:
872     case DW_OP_push_object_addres:
873     case DW_OP_call2:
874     case DW_OP_call4:
875     case DW_OP_call_ref:
876     default:
877       _LIBUNWIND_ABORT("DWARF opcode not implemented");
878     }
879 
880   }
881   if (log)
882     fprintf(stderr, "expression evaluates to 0x%" PRIx64 "\n", (uint64_t)*sp);
883   return *sp;
884 }
885 
886 
887 
888 } // namespace libunwind
889 
890 #endif // __DWARF_INSTRUCTIONS_HPP__
891