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      1 //===--------------------- Unwind_AppleExtras.cpp -------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is dual licensed under the MIT and the University of Illinois Open
      6 // Source Licenses. See LICENSE.TXT for details.
      7 //
      8 //
      9 //===----------------------------------------------------------------------===//
     10 
     11 #include "config.h"
     12 #include "DwarfParser.hpp"
     13 #include "unwind_ext.h"
     14 
     15 
     16 // private keymgr stuff
     17 #define KEYMGR_GCC3_DW2_OBJ_LIST 302
     18 extern "C" {
     19  extern void _keymgr_set_and_unlock_processwide_ptr(int key, void *ptr);
     20  extern void *_keymgr_get_and_lock_processwide_ptr(int key);
     21 }
     22 
     23 // undocumented libgcc "struct object"
     24 struct libgcc_object {
     25   void          *start;
     26   void          *unused1;
     27   void          *unused2;
     28   void          *fde;
     29   unsigned long  encoding;
     30   void          *fde_end;
     31   libgcc_object *next;
     32 };
     33 
     34 // undocumented libgcc "struct km_object_info" referenced by
     35 // KEYMGR_GCC3_DW2_OBJ_LIST
     36 struct libgcc_object_info {
     37   libgcc_object   *seen_objects;
     38   libgcc_object   *unseen_objects;
     39   unsigned         spare[2];
     40 };
     41 
     42 
     43 // static linker symbols to prevent wrong two level namespace for _Unwind symbols
     44 #if defined(__arm__)
     45    #define NOT_HERE_BEFORE_5_0(sym)     \
     46        extern const char sym##_tmp30 __asm("$ld$hide$os3.0$_" #sym ); \
     47        __attribute__((visibility("default"))) const char sym##_tmp30 = 0; \
     48        extern const char sym##_tmp31 __asm("$ld$hide$os3.1$_" #sym ); \
     49           __attribute__((visibility("default"))) const char sym##_tmp31 = 0; \
     50        extern const char sym##_tmp32 __asm("$ld$hide$os3.2$_" #sym );\
     51            __attribute__((visibility("default"))) const char sym##_tmp32 = 0; \
     52        extern const char sym##_tmp40 __asm("$ld$hide$os4.0$_" #sym ); \
     53           __attribute__((visibility("default"))) const char sym##_tmp40 = 0; \
     54        extern const char sym##_tmp41 __asm("$ld$hide$os4.1$_" #sym ); \
     55           __attribute__((visibility("default"))) const char sym##_tmp41 = 0; \
     56        extern const char sym##_tmp42 __asm("$ld$hide$os4.2$_" #sym ); \
     57           __attribute__((visibility("default"))) const char sym##_tmp42 = 0; \
     58        extern const char sym##_tmp43 __asm("$ld$hide$os4.3$_" #sym ); \
     59           __attribute__((visibility("default"))) const char sym##_tmp43 = 0;
     60 #elif defined(__arm64__)
     61   #define NOT_HERE_BEFORE_10_6(sym)
     62   #define NEVER_HERE(sym)
     63 #else
     64   #define NOT_HERE_BEFORE_10_6(sym) \
     65     extern const char sym##_tmp4 __asm("$ld$hide$os10.4$_" #sym ); \
     66           __attribute__((visibility("default"))) const char sym##_tmp4 = 0; \
     67     extern const char sym##_tmp5 __asm("$ld$hide$os10.5$_" #sym ); \
     68           __attribute__((visibility("default"))) const char sym##_tmp5 = 0;
     69   #define NEVER_HERE(sym) \
     70     extern const char sym##_tmp4 __asm("$ld$hide$os10.4$_" #sym ); \
     71           __attribute__((visibility("default"))) const char sym##_tmp4 = 0; \
     72     extern const char sym##_tmp5 __asm("$ld$hide$os10.5$_" #sym ); \
     73           __attribute__((visibility("default"))) const char sym##_tmp5 = 0; \
     74     extern const char sym##_tmp6 __asm("$ld$hide$os10.6$_" #sym ); \
     75           __attribute__((visibility("default"))) const char sym##_tmp6 = 0;
     76 #endif
     77 
     78 
     79 #if _LIBUNWIND_BUILD_ZERO_COST_APIS
     80 
     81 //
     82 // symbols in libSystem.dylib in 10.6 and later, but are in libgcc_s.dylib in
     83 // earlier versions
     84 //
     85 NOT_HERE_BEFORE_10_6(_Unwind_DeleteException)
     86 NOT_HERE_BEFORE_10_6(_Unwind_Find_FDE)
     87 NOT_HERE_BEFORE_10_6(_Unwind_ForcedUnwind)
     88 NOT_HERE_BEFORE_10_6(_Unwind_GetGR)
     89 NOT_HERE_BEFORE_10_6(_Unwind_GetIP)
     90 NOT_HERE_BEFORE_10_6(_Unwind_GetLanguageSpecificData)
     91 NOT_HERE_BEFORE_10_6(_Unwind_GetRegionStart)
     92 NOT_HERE_BEFORE_10_6(_Unwind_RaiseException)
     93 NOT_HERE_BEFORE_10_6(_Unwind_Resume)
     94 NOT_HERE_BEFORE_10_6(_Unwind_SetGR)
     95 NOT_HERE_BEFORE_10_6(_Unwind_SetIP)
     96 NOT_HERE_BEFORE_10_6(_Unwind_Backtrace)
     97 NOT_HERE_BEFORE_10_6(_Unwind_FindEnclosingFunction)
     98 NOT_HERE_BEFORE_10_6(_Unwind_GetCFA)
     99 NOT_HERE_BEFORE_10_6(_Unwind_GetDataRelBase)
    100 NOT_HERE_BEFORE_10_6(_Unwind_GetTextRelBase)
    101 NOT_HERE_BEFORE_10_6(_Unwind_Resume_or_Rethrow)
    102 NOT_HERE_BEFORE_10_6(_Unwind_GetIPInfo)
    103 NOT_HERE_BEFORE_10_6(__register_frame)
    104 NOT_HERE_BEFORE_10_6(__deregister_frame)
    105 
    106 //
    107 // symbols in libSystem.dylib for compatibility, but we don't want any new code
    108 // using them
    109 //
    110 NEVER_HERE(__register_frame_info_bases)
    111 NEVER_HERE(__register_frame_info)
    112 NEVER_HERE(__register_frame_info_table_bases)
    113 NEVER_HERE(__register_frame_info_table)
    114 NEVER_HERE(__register_frame_table)
    115 NEVER_HERE(__deregister_frame_info)
    116 NEVER_HERE(__deregister_frame_info_bases)
    117 
    118 #endif // _LIBUNWIND_BUILD_ZERO_COST_APIS
    119 
    120 
    121 
    122 
    123 #if _LIBUNWIND_BUILD_SJLJ_APIS
    124 //
    125 // symbols in libSystem.dylib in iOS 5.0 and later, but are in libgcc_s.dylib in
    126 // earlier versions
    127 //
    128 NOT_HERE_BEFORE_5_0(_Unwind_GetLanguageSpecificData)
    129 NOT_HERE_BEFORE_5_0(_Unwind_GetRegionStart)
    130 NOT_HERE_BEFORE_5_0(_Unwind_GetIP)
    131 NOT_HERE_BEFORE_5_0(_Unwind_SetGR)
    132 NOT_HERE_BEFORE_5_0(_Unwind_SetIP)
    133 NOT_HERE_BEFORE_5_0(_Unwind_DeleteException)
    134 NOT_HERE_BEFORE_5_0(_Unwind_SjLj_Register)
    135 NOT_HERE_BEFORE_5_0(_Unwind_GetGR)
    136 NOT_HERE_BEFORE_5_0(_Unwind_GetIPInfo)
    137 NOT_HERE_BEFORE_5_0(_Unwind_GetCFA)
    138 NOT_HERE_BEFORE_5_0(_Unwind_SjLj_Resume)
    139 NOT_HERE_BEFORE_5_0(_Unwind_SjLj_RaiseException)
    140 NOT_HERE_BEFORE_5_0(_Unwind_SjLj_Resume_or_Rethrow)
    141 NOT_HERE_BEFORE_5_0(_Unwind_SjLj_Unregister)
    142 
    143 #endif // _LIBUNWIND_BUILD_SJLJ_APIS
    144 
    145 
    146 namespace libunwind {
    147 
    148 _LIBUNWIND_HIDDEN
    149 bool checkKeyMgrRegisteredFDEs(uintptr_t pc, void *&fde) {
    150 #if __MAC_OS_X_VERSION_MIN_REQUIRED
    151   // lastly check for old style keymgr registration of dynamically generated
    152   // FDEs acquire exclusive access to libgcc_object_info
    153   libgcc_object_info *head = (libgcc_object_info *)
    154                 _keymgr_get_and_lock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST);
    155   if (head != NULL) {
    156     // look at each FDE in keymgr
    157     for (libgcc_object *ob = head->unseen_objects; ob != NULL; ob = ob->next) {
    158       CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
    159       CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
    160       const char *msg = CFI_Parser<LocalAddressSpace>::decodeFDE(
    161                                       LocalAddressSpace::sThisAddressSpace,
    162                                       (uintptr_t)ob->fde, &fdeInfo, &cieInfo);
    163       if (msg == NULL) {
    164         // Check if this FDE is for a function that includes the pc
    165         if ((fdeInfo.pcStart <= pc) && (pc < fdeInfo.pcEnd)) {
    166           fde = (void*)fdeInfo.pcStart;
    167           _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST,
    168                                                  head);
    169           return true;
    170         }
    171       }
    172     }
    173   }
    174   // release libgcc_object_info
    175   _keymgr_set_and_unlock_processwide_ptr(KEYMGR_GCC3_DW2_OBJ_LIST, head);
    176 #else
    177   (void)pc;
    178   (void)fde;
    179 #endif
    180   return false;
    181 }
    182 
    183 }
    184 
    185 
    186 #if !defined(FOR_DYLD) && _LIBUNWIND_BUILD_SJLJ_APIS
    187 
    188 #include <System/pthread_machdep.h>
    189 
    190 // Accessors to get get/set linked list of frames for sjlj based execeptions.
    191 _LIBUNWIND_HIDDEN
    192 struct _Unwind_FunctionContext *__Unwind_SjLj_GetTopOfFunctionStack() {
    193   return (struct _Unwind_FunctionContext *)
    194     _pthread_getspecific_direct(__PTK_LIBC_DYLD_Unwind_SjLj_Key);
    195 }
    196 
    197 _LIBUNWIND_HIDDEN
    198 void __Unwind_SjLj_SetTopOfFunctionStack(struct _Unwind_FunctionContext *fc) {
    199   _pthread_setspecific_direct(__PTK_LIBC_DYLD_Unwind_SjLj_Key, fc);
    200 }
    201 #endif
    202 
    203 
    204 
    205 
    206