xref: /freebsd/contrib/llvm-project/libunwind/src/DwarfInstructions.hpp (revision 700637cbb5e582861067a11aaca4d053546871d2)
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 "DwarfParser.hpp"
20 #include "Registers.hpp"
21 #include "config.h"
22 #include "dwarf2.h"
23 #include "libunwind_ext.h"
24 
25 
26 namespace libunwind {
27 
28 
29 /// DwarfInstructions maps abstract DWARF unwind instructions to a particular
30 /// architecture
31 template <typename A, typename R>
32 class DwarfInstructions {
33 public:
34   typedef typename A::pint_t pint_t;
35   typedef typename A::sint_t sint_t;
36 
37   static int stepWithDwarf(A &addressSpace, pint_t pc, pint_t fdeStart,
38                            R &registers, bool &isSignalFrame, bool stage2);
39 
40 private:
41 
42   enum {
43     DW_X86_64_RET_ADDR = 16
44   };
45 
46   enum {
47     DW_X86_RET_ADDR = 8
48   };
49 
50   typedef typename CFI_Parser<A>::RegisterLocation  RegisterLocation;
51   typedef typename CFI_Parser<A>::PrologInfo        PrologInfo;
52   typedef typename CFI_Parser<A>::FDE_Info          FDE_Info;
53   typedef typename CFI_Parser<A>::CIE_Info          CIE_Info;
54 
55   static pint_t evaluateExpression(pint_t expression, A &addressSpace,
56                                    const R &registers,
57                                    pint_t initialStackValue);
58   static pint_t getSavedRegister(A &addressSpace, const R &registers,
59                                  pint_t cfa, const RegisterLocation &savedReg);
60   static double getSavedFloatRegister(A &addressSpace, const R &registers,
61                                   pint_t cfa, const RegisterLocation &savedReg);
62   static v128 getSavedVectorRegister(A &addressSpace, const R &registers,
63                                   pint_t cfa, const RegisterLocation &savedReg);
64 
getCFA(A & addressSpace,const PrologInfo & prolog,const R & registers)65   static pint_t getCFA(A &addressSpace, const PrologInfo &prolog,
66                        const R &registers) {
67     if (prolog.cfaRegister != 0)
68       return (pint_t)((sint_t)registers.getRegister((int)prolog.cfaRegister) +
69              prolog.cfaRegisterOffset);
70     if (prolog.cfaExpression != 0)
71       return evaluateExpression((pint_t)prolog.cfaExpression, addressSpace,
72                                 registers, 0);
73     assert(0 && "getCFA(): unknown location");
74     __builtin_unreachable();
75   }
76 #if defined(_LIBUNWIND_TARGET_AARCH64)
77   static bool isReturnAddressSigned(A &addressSpace, R registers, pint_t cfa,
78                                     PrologInfo &prolog);
79   static bool isReturnAddressSignedWithPC(A &addressSpace, R registers,
80                                           pint_t cfa, PrologInfo &prolog);
81 #endif
82 };
83 
84 template <typename R>
getSparcWCookie(const R & r,int)85 auto getSparcWCookie(const R &r, int) -> decltype(r.getWCookie()) {
86   return r.getWCookie();
87 }
getSparcWCookie(const R &,long)88 template <typename R> uint64_t getSparcWCookie(const R &, long) {
89   return 0;
90 }
91 
92 template <typename A, typename R>
getSavedRegister(A & addressSpace,const R & registers,pint_t cfa,const RegisterLocation & savedReg)93 typename A::pint_t DwarfInstructions<A, R>::getSavedRegister(
94     A &addressSpace, const R &registers, pint_t cfa,
95     const RegisterLocation &savedReg) {
96   switch (savedReg.location) {
97   case CFI_Parser<A>::kRegisterInCFA:
98     return (pint_t)addressSpace.getRegister(cfa + (pint_t)savedReg.value);
99 
100   case CFI_Parser<A>::kRegisterInCFADecrypt: // sparc64 specific
101     return (pint_t)(addressSpace.getP(cfa + (pint_t)savedReg.value) ^
102            getSparcWCookie(registers, 0));
103 
104   case CFI_Parser<A>::kRegisterAtExpression:
105     return (pint_t)addressSpace.getRegister(evaluateExpression(
106         (pint_t)savedReg.value, addressSpace, registers, cfa));
107 
108   case CFI_Parser<A>::kRegisterIsExpression:
109     return evaluateExpression((pint_t)savedReg.value, addressSpace,
110                               registers, cfa);
111 
112   case CFI_Parser<A>::kRegisterInRegister:
113     return registers.getRegister((int)savedReg.value);
114 
115   case CFI_Parser<A>::kRegisterUnused:
116   case CFI_Parser<A>::kRegisterOffsetFromCFA:
117     // FIX ME
118     break;
119   }
120   _LIBUNWIND_ABORT("unsupported restore location for register");
121 }
122 
123 template <typename A, typename R>
getSavedFloatRegister(A & addressSpace,const R & registers,pint_t cfa,const RegisterLocation & savedReg)124 double DwarfInstructions<A, R>::getSavedFloatRegister(
125     A &addressSpace, const R &registers, pint_t cfa,
126     const RegisterLocation &savedReg) {
127   switch (savedReg.location) {
128   case CFI_Parser<A>::kRegisterInCFA:
129     return addressSpace.getDouble(cfa + (pint_t)savedReg.value);
130 
131   case CFI_Parser<A>::kRegisterAtExpression:
132     return addressSpace.getDouble(
133         evaluateExpression((pint_t)savedReg.value, addressSpace,
134                             registers, cfa));
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>
getSavedVectorRegister(A & addressSpace,const R & registers,pint_t cfa,const RegisterLocation & savedReg)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>::kRegisterOffsetFromCFA:
165   case CFI_Parser<A>::kRegisterInRegister:
166   case CFI_Parser<A>::kRegisterInCFADecrypt:
167     // FIX ME
168     break;
169   }
170   _LIBUNWIND_ABORT("unsupported restore location for vector register");
171 }
172 #if defined(_LIBUNWIND_TARGET_AARCH64)
173 template <typename A, typename R>
isReturnAddressSigned(A & addressSpace,R registers,pint_t cfa,PrologInfo & prolog)174 bool DwarfInstructions<A, R>::isReturnAddressSigned(A &addressSpace,
175                                                     R registers, pint_t cfa,
176                                                     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 
188 template <typename A, typename R>
isReturnAddressSignedWithPC(A & addressSpace,R registers,pint_t cfa,PrologInfo & prolog)189 bool DwarfInstructions<A, R>::isReturnAddressSignedWithPC(A &addressSpace,
190                                                           R registers,
191                                                           pint_t cfa,
192                                                           PrologInfo &prolog) {
193   pint_t raSignState;
194   auto regloc = prolog.savedRegisters[UNW_AARCH64_RA_SIGN_STATE];
195   if (regloc.location == CFI_Parser<A>::kRegisterUnused)
196     raSignState = static_cast<pint_t>(regloc.value);
197   else
198     raSignState = getSavedRegister(addressSpace, registers, cfa, regloc);
199 
200   // Only bit[1] is meaningful.
201   return raSignState & 0x02;
202 }
203 #endif
204 
205 template <typename A, typename R>
stepWithDwarf(A & addressSpace,pint_t pc,pint_t fdeStart,R & registers,bool & isSignalFrame,bool stage2)206 int DwarfInstructions<A, R>::stepWithDwarf(A &addressSpace, pint_t pc,
207                                            pint_t fdeStart, R &registers,
208                                            bool &isSignalFrame, bool stage2) {
209   FDE_Info fdeInfo;
210   CIE_Info cieInfo;
211   if (CFI_Parser<A>::decodeFDE(addressSpace, fdeStart, &fdeInfo,
212                                &cieInfo) == NULL) {
213     PrologInfo prolog;
214     if (CFI_Parser<A>::parseFDEInstructions(addressSpace, fdeInfo, cieInfo, pc,
215                                             R::getArch(), &prolog)) {
216       // get pointer to cfa (architecture specific)
217       pint_t cfa = getCFA(addressSpace, prolog, registers);
218 
219       (void)stage2;
220       // __unw_step_stage2 is not used for cross unwinding, so we use
221       // __aarch64__ rather than LIBUNWIND_TARGET_AARCH64 to make sure we are
222       // building for AArch64 natively.
223 #if defined(__aarch64__)
224       if (stage2 && cieInfo.mteTaggedFrame) {
225         pint_t sp = registers.getSP();
226         pint_t p = sp;
227         // AArch64 doesn't require the value of SP to be 16-byte aligned at
228         // all times, only at memory accesses and public interfaces [1]. Thus,
229         // a signal could arrive at a point where SP is not aligned properly.
230         // In that case, the kernel fixes up [2] the signal frame, but we
231         // still have a misaligned SP in the previous frame. If that signal
232         // handler caused stack unwinding, we would have an unaligned SP.
233         // We do not need to fix up the CFA, as that is the SP at a "public
234         // interface".
235         // [1]:
236         // https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#622the-stack
237         // [2]:
238         // https://github.com/torvalds/linux/blob/1930a6e739c4b4a654a69164dbe39e554d228915/arch/arm64/kernel/signal.c#L718
239         p &= ~0xfULL;
240         // CFA is the bottom of the current stack frame.
241         for (; p < cfa; p += 16) {
242           __asm__ __volatile__(".arch armv8.5-a\n"
243                                ".arch_extension memtag\n"
244                                "stg %[Ptr], [%[Ptr]]\n"
245                                :
246                                : [Ptr] "r"(p)
247                                : "memory");
248         }
249       }
250 #endif
251       // restore registers that DWARF says were saved
252       R newRegisters = registers;
253 
254       // Typically, the CFA is the stack pointer at the call site in
255       // the previous frame. However, there are scenarios in which this is not
256       // true. For example, if we switched to a new stack. In that case, the
257       // value of the previous SP might be indicated by a CFI directive.
258       //
259       // We set the SP here to the CFA, allowing for it to be overridden
260       // by a CFI directive later on.
261       newRegisters.setSP(cfa);
262 
263       pint_t returnAddress = 0;
264       constexpr int lastReg = R::lastDwarfRegNum();
265       static_assert(static_cast<int>(CFI_Parser<A>::kMaxRegisterNumber) >=
266                         lastReg,
267                     "register range too large");
268       assert(lastReg >= (int)cieInfo.returnAddressRegister &&
269              "register range does not contain return address register");
270       for (int i = 0; i <= lastReg; ++i) {
271         if (prolog.savedRegisters[i].location !=
272             CFI_Parser<A>::kRegisterUnused) {
273           if (registers.validFloatRegister(i))
274             newRegisters.setFloatRegister(
275                 i, getSavedFloatRegister(addressSpace, registers, cfa,
276                                          prolog.savedRegisters[i]));
277           else if (registers.validVectorRegister(i))
278             newRegisters.setVectorRegister(
279                 i, getSavedVectorRegister(addressSpace, registers, cfa,
280                                           prolog.savedRegisters[i]));
281           else if (i == (int)cieInfo.returnAddressRegister)
282             returnAddress = getSavedRegister(addressSpace, registers, cfa,
283                                              prolog.savedRegisters[i]);
284           else if (registers.validRegister(i))
285             newRegisters.setRegister(
286                 i, getSavedRegister(addressSpace, registers, cfa,
287                                     prolog.savedRegisters[i]));
288           else
289             return UNW_EBADREG;
290         }
291       }
292 
293       isSignalFrame = cieInfo.isSignalFrame;
294 
295 #if defined(_LIBUNWIND_TARGET_AARCH64)
296       // If the target is aarch64 then the return address may have been signed
297       // using the v8.3 pointer authentication extensions. The original
298       // return address needs to be authenticated before the return address is
299       // restored. autia1716 is used instead of autia as autia1716 assembles
300       // to a NOP on pre-v8.3a architectures.
301       if ((R::getArch() == REGISTERS_ARM64) &&
302           isReturnAddressSigned(addressSpace, registers, cfa, prolog) &&
303           returnAddress != 0) {
304 #if !defined(_LIBUNWIND_IS_NATIVE_ONLY)
305         return UNW_ECROSSRASIGNING;
306 #else
307         register unsigned long long x17 __asm("x17") = returnAddress;
308         register unsigned long long x16 __asm("x16") = cfa;
309 
310         // We use the hint versions of the authentication instructions below to
311         // ensure they're assembled by the compiler even for targets with no
312         // FEAT_PAuth/FEAT_PAuth_LR support.
313         if (isReturnAddressSignedWithPC(addressSpace, registers, cfa, prolog)) {
314           register unsigned long long x15 __asm("x15") =
315               prolog.ptrAuthDiversifier;
316           if (cieInfo.addressesSignedWithBKey) {
317             asm("hint 0x27\n\t" // pacm
318                 "hint 0xe"
319                 : "+r"(x17)
320                 : "r"(x16), "r"(x15)); // autib1716
321           } else {
322             asm("hint 0x27\n\t" // pacm
323                 "hint 0xc"
324                 : "+r"(x17)
325                 : "r"(x16), "r"(x15)); // autia1716
326           }
327         } else {
328           if (cieInfo.addressesSignedWithBKey)
329             asm("hint 0xe" : "+r"(x17) : "r"(x16)); // autib1716
330           else
331             asm("hint 0xc" : "+r"(x17) : "r"(x16)); // autia1716
332         }
333         returnAddress = x17;
334 #endif
335       }
336 #endif
337 
338 #if defined(_LIBUNWIND_IS_NATIVE_ONLY) && defined(_LIBUNWIND_TARGET_ARM) &&    \
339     defined(__ARM_FEATURE_PAUTH)
340       if ((R::getArch() == REGISTERS_ARM) &&
341           prolog.savedRegisters[UNW_ARM_RA_AUTH_CODE].value) {
342         pint_t pac =
343             getSavedRegister(addressSpace, registers, cfa,
344                              prolog.savedRegisters[UNW_ARM_RA_AUTH_CODE]);
345         __asm__ __volatile__("autg %0, %1, %2"
346                              :
347                              : "r"(pac), "r"(returnAddress), "r"(cfa)
348                              :);
349       }
350 #endif
351 
352 #if defined(_LIBUNWIND_TARGET_SPARC)
353       if (R::getArch() == REGISTERS_SPARC) {
354         // Skip call site instruction and delay slot
355         returnAddress += 8;
356         // Skip unimp instruction if function returns a struct
357         if ((addressSpace.get32(returnAddress) & 0xC1C00000) == 0)
358           returnAddress += 4;
359       }
360 #endif
361 
362 #if defined(_LIBUNWIND_TARGET_SPARC64)
363       // Skip call site instruction and delay slot.
364       if (R::getArch() == REGISTERS_SPARC64)
365         returnAddress += 8;
366 #endif
367 
368 #if defined(_LIBUNWIND_TARGET_PPC64)
369 #define PPC64_ELFV1_R2_LOAD_INST_ENCODING 0xe8410028u // ld r2,40(r1)
370 #define PPC64_ELFV1_R2_OFFSET 40
371 #define PPC64_ELFV2_R2_LOAD_INST_ENCODING 0xe8410018u // ld r2,24(r1)
372 #define PPC64_ELFV2_R2_OFFSET 24
373       // If the instruction at return address is a TOC (r2) restore,
374       // then r2 was saved and needs to be restored.
375       // ELFv2 ABI specifies that the TOC Pointer must be saved at SP + 24,
376       // while in ELFv1 ABI it is saved at SP + 40.
377       if (R::getArch() == REGISTERS_PPC64 && returnAddress != 0) {
378         pint_t sp = newRegisters.getRegister(UNW_REG_SP);
379         pint_t r2 = 0;
380         switch (addressSpace.get32(returnAddress)) {
381         case PPC64_ELFV1_R2_LOAD_INST_ENCODING:
382           r2 = addressSpace.get64(sp + PPC64_ELFV1_R2_OFFSET);
383           break;
384         case PPC64_ELFV2_R2_LOAD_INST_ENCODING:
385           r2 = addressSpace.get64(sp + PPC64_ELFV2_R2_OFFSET);
386           break;
387         }
388         if (r2)
389           newRegisters.setRegister(UNW_PPC64_R2, r2);
390       }
391 #endif
392 
393       // Return address is address after call site instruction, so setting IP to
394       // that does simulates a return.
395       newRegisters.setIP(returnAddress);
396 
397       // Simulate the step by replacing the register set with the new ones.
398       registers = newRegisters;
399 
400       return UNW_STEP_SUCCESS;
401     }
402   }
403   return UNW_EBADFRAME;
404 }
405 
406 template <typename A, typename R>
407 typename A::pint_t
evaluateExpression(pint_t expression,A & addressSpace,const R & registers,pint_t initialStackValue)408 DwarfInstructions<A, R>::evaluateExpression(pint_t expression, A &addressSpace,
409                                             const R &registers,
410                                             pint_t initialStackValue) {
411   const bool log = false;
412   pint_t p = expression;
413   pint_t expressionEnd = expression + 20; // temp, until len read
414   pint_t length = (pint_t)addressSpace.getULEB128(p, expressionEnd);
415   expressionEnd = p + length;
416   if (log)
417     fprintf(stderr, "evaluateExpression(): length=%" PRIu64 "\n",
418             (uint64_t)length);
419   pint_t stack[100];
420   pint_t *sp = stack;
421   *(++sp) = initialStackValue;
422 
423   while (p < expressionEnd) {
424     if (log) {
425       for (pint_t *t = sp; t > stack; --t) {
426         fprintf(stderr, "sp[] = 0x%" PRIx64 "\n", (uint64_t)(*t));
427       }
428     }
429     uint8_t opcode = addressSpace.get8(p++);
430     sint_t svalue, svalue2;
431     pint_t value;
432     uint32_t reg;
433     switch (opcode) {
434     case DW_OP_addr:
435       // push immediate address sized value
436       value = addressSpace.getP(p);
437       p += sizeof(pint_t);
438       *(++sp) = value;
439       if (log)
440         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
441       break;
442 
443     case DW_OP_deref:
444       // pop stack, dereference, push result
445       value = *sp--;
446       *(++sp) = addressSpace.getP(value);
447       if (log)
448         fprintf(stderr, "dereference 0x%" PRIx64 "\n", (uint64_t)value);
449       break;
450 
451     case DW_OP_const1u:
452       // push immediate 1 byte value
453       value = addressSpace.get8(p);
454       p += 1;
455       *(++sp) = value;
456       if (log)
457         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
458       break;
459 
460     case DW_OP_const1s:
461       // push immediate 1 byte signed value
462       svalue = (int8_t) addressSpace.get8(p);
463       p += 1;
464       *(++sp) = (pint_t)svalue;
465       if (log)
466         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
467       break;
468 
469     case DW_OP_const2u:
470       // push immediate 2 byte value
471       value = addressSpace.get16(p);
472       p += 2;
473       *(++sp) = value;
474       if (log)
475         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
476       break;
477 
478     case DW_OP_const2s:
479       // push immediate 2 byte signed value
480       svalue = (int16_t) addressSpace.get16(p);
481       p += 2;
482       *(++sp) = (pint_t)svalue;
483       if (log)
484         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
485       break;
486 
487     case DW_OP_const4u:
488       // push immediate 4 byte value
489       value = addressSpace.get32(p);
490       p += 4;
491       *(++sp) = value;
492       if (log)
493         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
494       break;
495 
496     case DW_OP_const4s:
497       // push immediate 4 byte signed value
498       svalue = (int32_t)addressSpace.get32(p);
499       p += 4;
500       *(++sp) = (pint_t)svalue;
501       if (log)
502         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
503       break;
504 
505     case DW_OP_const8u:
506       // push immediate 8 byte value
507       value = (pint_t)addressSpace.get64(p);
508       p += 8;
509       *(++sp) = value;
510       if (log)
511         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
512       break;
513 
514     case DW_OP_const8s:
515       // push immediate 8 byte signed value
516       value = (pint_t)addressSpace.get64(p);
517       p += 8;
518       *(++sp) = value;
519       if (log)
520         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
521       break;
522 
523     case DW_OP_constu:
524       // push immediate ULEB128 value
525       value = (pint_t)addressSpace.getULEB128(p, expressionEnd);
526       *(++sp) = value;
527       if (log)
528         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)value);
529       break;
530 
531     case DW_OP_consts:
532       // push immediate SLEB128 value
533       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
534       *(++sp) = (pint_t)svalue;
535       if (log)
536         fprintf(stderr, "push 0x%" PRIx64 "\n", (uint64_t)svalue);
537       break;
538 
539     case DW_OP_dup:
540       // push top of stack
541       value = *sp;
542       *(++sp) = value;
543       if (log)
544         fprintf(stderr, "duplicate top of stack\n");
545       break;
546 
547     case DW_OP_drop:
548       // pop
549       --sp;
550       if (log)
551         fprintf(stderr, "pop top of stack\n");
552       break;
553 
554     case DW_OP_over:
555       // dup second
556       value = sp[-1];
557       *(++sp) = value;
558       if (log)
559         fprintf(stderr, "duplicate second in stack\n");
560       break;
561 
562     case DW_OP_pick:
563       // pick from
564       reg = addressSpace.get8(p);
565       p += 1;
566       value = sp[-(int)reg];
567       *(++sp) = value;
568       if (log)
569         fprintf(stderr, "duplicate %d in stack\n", reg);
570       break;
571 
572     case DW_OP_swap:
573       // swap top two
574       value = sp[0];
575       sp[0] = sp[-1];
576       sp[-1] = value;
577       if (log)
578         fprintf(stderr, "swap top of stack\n");
579       break;
580 
581     case DW_OP_rot:
582       // rotate top three
583       value = sp[0];
584       sp[0] = sp[-1];
585       sp[-1] = sp[-2];
586       sp[-2] = value;
587       if (log)
588         fprintf(stderr, "rotate top three of stack\n");
589       break;
590 
591     case DW_OP_xderef:
592       // pop stack, dereference, push result
593       value = *sp--;
594       *sp = *((pint_t*)value);
595       if (log)
596         fprintf(stderr, "x-dereference 0x%" PRIx64 "\n", (uint64_t)value);
597       break;
598 
599     case DW_OP_abs:
600       svalue = (sint_t)*sp;
601       if (svalue < 0)
602         *sp = (pint_t)(-svalue);
603       if (log)
604         fprintf(stderr, "abs\n");
605       break;
606 
607     case DW_OP_and:
608       value = *sp--;
609       *sp &= value;
610       if (log)
611         fprintf(stderr, "and\n");
612       break;
613 
614     case DW_OP_div:
615       svalue = (sint_t)(*sp--);
616       svalue2 = (sint_t)*sp;
617       *sp = (pint_t)(svalue2 / svalue);
618       if (log)
619         fprintf(stderr, "div\n");
620       break;
621 
622     case DW_OP_minus:
623       value = *sp--;
624       *sp = *sp - value;
625       if (log)
626         fprintf(stderr, "minus\n");
627       break;
628 
629     case DW_OP_mod:
630       svalue = (sint_t)(*sp--);
631       svalue2 = (sint_t)*sp;
632       *sp = (pint_t)(svalue2 % svalue);
633       if (log)
634         fprintf(stderr, "module\n");
635       break;
636 
637     case DW_OP_mul:
638       svalue = (sint_t)(*sp--);
639       svalue2 = (sint_t)*sp;
640       *sp = (pint_t)(svalue2 * svalue);
641       if (log)
642         fprintf(stderr, "mul\n");
643       break;
644 
645     case DW_OP_neg:
646       *sp = 0 - *sp;
647       if (log)
648         fprintf(stderr, "neg\n");
649       break;
650 
651     case DW_OP_not:
652       svalue = (sint_t)(*sp);
653       *sp = (pint_t)(~svalue);
654       if (log)
655         fprintf(stderr, "not\n");
656       break;
657 
658     case DW_OP_or:
659       value = *sp--;
660       *sp |= value;
661       if (log)
662         fprintf(stderr, "or\n");
663       break;
664 
665     case DW_OP_plus:
666       value = *sp--;
667       *sp += value;
668       if (log)
669         fprintf(stderr, "plus\n");
670       break;
671 
672     case DW_OP_plus_uconst:
673       // pop stack, add uelb128 constant, push result
674       *sp += static_cast<pint_t>(addressSpace.getULEB128(p, expressionEnd));
675       if (log)
676         fprintf(stderr, "add constant\n");
677       break;
678 
679     case DW_OP_shl:
680       value = *sp--;
681       *sp = *sp << value;
682       if (log)
683         fprintf(stderr, "shift left\n");
684       break;
685 
686     case DW_OP_shr:
687       value = *sp--;
688       *sp = *sp >> value;
689       if (log)
690         fprintf(stderr, "shift left\n");
691       break;
692 
693     case DW_OP_shra:
694       value = *sp--;
695       svalue = (sint_t)*sp;
696       *sp = (pint_t)(svalue >> value);
697       if (log)
698         fprintf(stderr, "shift left arithmetic\n");
699       break;
700 
701     case DW_OP_xor:
702       value = *sp--;
703       *sp ^= value;
704       if (log)
705         fprintf(stderr, "xor\n");
706       break;
707 
708     case DW_OP_skip:
709       svalue = (int16_t) addressSpace.get16(p);
710       p += 2;
711       p = (pint_t)((sint_t)p + svalue);
712       if (log)
713         fprintf(stderr, "skip %" PRIu64 "\n", (uint64_t)svalue);
714       break;
715 
716     case DW_OP_bra:
717       svalue = (int16_t) addressSpace.get16(p);
718       p += 2;
719       if (*sp--)
720         p = (pint_t)((sint_t)p + svalue);
721       if (log)
722         fprintf(stderr, "bra %" PRIu64 "\n", (uint64_t)svalue);
723       break;
724 
725     case DW_OP_eq:
726       value = *sp--;
727       *sp = (*sp == value);
728       if (log)
729         fprintf(stderr, "eq\n");
730       break;
731 
732     case DW_OP_ge:
733       value = *sp--;
734       *sp = (*sp >= value);
735       if (log)
736         fprintf(stderr, "ge\n");
737       break;
738 
739     case DW_OP_gt:
740       value = *sp--;
741       *sp = (*sp > value);
742       if (log)
743         fprintf(stderr, "gt\n");
744       break;
745 
746     case DW_OP_le:
747       value = *sp--;
748       *sp = (*sp <= value);
749       if (log)
750         fprintf(stderr, "le\n");
751       break;
752 
753     case DW_OP_lt:
754       value = *sp--;
755       *sp = (*sp < value);
756       if (log)
757         fprintf(stderr, "lt\n");
758       break;
759 
760     case DW_OP_ne:
761       value = *sp--;
762       *sp = (*sp != value);
763       if (log)
764         fprintf(stderr, "ne\n");
765       break;
766 
767     case DW_OP_lit0:
768     case DW_OP_lit1:
769     case DW_OP_lit2:
770     case DW_OP_lit3:
771     case DW_OP_lit4:
772     case DW_OP_lit5:
773     case DW_OP_lit6:
774     case DW_OP_lit7:
775     case DW_OP_lit8:
776     case DW_OP_lit9:
777     case DW_OP_lit10:
778     case DW_OP_lit11:
779     case DW_OP_lit12:
780     case DW_OP_lit13:
781     case DW_OP_lit14:
782     case DW_OP_lit15:
783     case DW_OP_lit16:
784     case DW_OP_lit17:
785     case DW_OP_lit18:
786     case DW_OP_lit19:
787     case DW_OP_lit20:
788     case DW_OP_lit21:
789     case DW_OP_lit22:
790     case DW_OP_lit23:
791     case DW_OP_lit24:
792     case DW_OP_lit25:
793     case DW_OP_lit26:
794     case DW_OP_lit27:
795     case DW_OP_lit28:
796     case DW_OP_lit29:
797     case DW_OP_lit30:
798     case DW_OP_lit31:
799       value = static_cast<pint_t>(opcode - DW_OP_lit0);
800       *(++sp) = value;
801       if (log)
802         fprintf(stderr, "push literal 0x%" PRIx64 "\n", (uint64_t)value);
803       break;
804 
805     case DW_OP_reg0:
806     case DW_OP_reg1:
807     case DW_OP_reg2:
808     case DW_OP_reg3:
809     case DW_OP_reg4:
810     case DW_OP_reg5:
811     case DW_OP_reg6:
812     case DW_OP_reg7:
813     case DW_OP_reg8:
814     case DW_OP_reg9:
815     case DW_OP_reg10:
816     case DW_OP_reg11:
817     case DW_OP_reg12:
818     case DW_OP_reg13:
819     case DW_OP_reg14:
820     case DW_OP_reg15:
821     case DW_OP_reg16:
822     case DW_OP_reg17:
823     case DW_OP_reg18:
824     case DW_OP_reg19:
825     case DW_OP_reg20:
826     case DW_OP_reg21:
827     case DW_OP_reg22:
828     case DW_OP_reg23:
829     case DW_OP_reg24:
830     case DW_OP_reg25:
831     case DW_OP_reg26:
832     case DW_OP_reg27:
833     case DW_OP_reg28:
834     case DW_OP_reg29:
835     case DW_OP_reg30:
836     case DW_OP_reg31:
837       reg = static_cast<uint32_t>(opcode - DW_OP_reg0);
838       *(++sp) = registers.getRegister((int)reg);
839       if (log)
840         fprintf(stderr, "push reg %d\n", reg);
841       break;
842 
843     case DW_OP_regx:
844       reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
845       *(++sp) = registers.getRegister((int)reg);
846       if (log)
847         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
848       break;
849 
850     case DW_OP_breg0:
851     case DW_OP_breg1:
852     case DW_OP_breg2:
853     case DW_OP_breg3:
854     case DW_OP_breg4:
855     case DW_OP_breg5:
856     case DW_OP_breg6:
857     case DW_OP_breg7:
858     case DW_OP_breg8:
859     case DW_OP_breg9:
860     case DW_OP_breg10:
861     case DW_OP_breg11:
862     case DW_OP_breg12:
863     case DW_OP_breg13:
864     case DW_OP_breg14:
865     case DW_OP_breg15:
866     case DW_OP_breg16:
867     case DW_OP_breg17:
868     case DW_OP_breg18:
869     case DW_OP_breg19:
870     case DW_OP_breg20:
871     case DW_OP_breg21:
872     case DW_OP_breg22:
873     case DW_OP_breg23:
874     case DW_OP_breg24:
875     case DW_OP_breg25:
876     case DW_OP_breg26:
877     case DW_OP_breg27:
878     case DW_OP_breg28:
879     case DW_OP_breg29:
880     case DW_OP_breg30:
881     case DW_OP_breg31:
882       reg = static_cast<uint32_t>(opcode - DW_OP_breg0);
883       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
884       svalue += static_cast<sint_t>(registers.getRegister((int)reg));
885       *(++sp) = (pint_t)(svalue);
886       if (log)
887         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
888       break;
889 
890     case DW_OP_bregx:
891       reg = static_cast<uint32_t>(addressSpace.getULEB128(p, expressionEnd));
892       svalue = (sint_t)addressSpace.getSLEB128(p, expressionEnd);
893       svalue += static_cast<sint_t>(registers.getRegister((int)reg));
894       *(++sp) = (pint_t)(svalue);
895       if (log)
896         fprintf(stderr, "push reg %d + 0x%" PRIx64 "\n", reg, (uint64_t)svalue);
897       break;
898 
899     case DW_OP_fbreg:
900       _LIBUNWIND_ABORT("DW_OP_fbreg not implemented");
901       break;
902 
903     case DW_OP_piece:
904       _LIBUNWIND_ABORT("DW_OP_piece not implemented");
905       break;
906 
907     case DW_OP_deref_size:
908       // pop stack, dereference, push result
909       value = *sp--;
910       switch (addressSpace.get8(p++)) {
911       case 1:
912         value = addressSpace.get8(value);
913         break;
914       case 2:
915         value = addressSpace.get16(value);
916         break;
917       case 4:
918         value = addressSpace.get32(value);
919         break;
920       case 8:
921         value = (pint_t)addressSpace.get64(value);
922         break;
923       default:
924         _LIBUNWIND_ABORT("DW_OP_deref_size with bad size");
925       }
926       *(++sp) = value;
927       if (log)
928         fprintf(stderr, "sized dereference 0x%" PRIx64 "\n", (uint64_t)value);
929       break;
930 
931     case DW_OP_xderef_size:
932     case DW_OP_nop:
933     case DW_OP_push_object_addres:
934     case DW_OP_call2:
935     case DW_OP_call4:
936     case DW_OP_call_ref:
937     default:
938       _LIBUNWIND_ABORT("DWARF opcode not implemented");
939     }
940 
941   }
942   if (log)
943     fprintf(stderr, "expression evaluates to 0x%" PRIx64 "\n", (uint64_t)*sp);
944   return *sp;
945 }
946 
947 
948 
949 } // namespace libunwind
950 
951 #endif // __DWARF_INSTRUCTIONS_HPP__
952