src/cpu_dep.c

   1 /*
   2 Copyright (C) 2001-2007, The Perl Foundation.
   3 $Id$
   4
   5 =head1 NAME
   6
   7 src/cpu_dep.c - CPU-dependent functions
   8
   9 =head1 DESCRIPTION
  10
  11 These functions are called while stackwalking during dead object
  12 destruction. They implement conditional CPU-specific behaviour related
  13 to register windowing.
  14
  15 Register windowing is a technique which avoids having to empty registers
  16 by moving a virtual window up/down the register stack restricting the
  17 number of registers which are visible.
  18
  19 Remember you read something about it in F<docs/infant.dev>?
  20
  21 =head2 Functions
  22
  23 */
  24
  25 #include "parrot/parrot.h"
  26
  27 /* HEADERIZER HFILE: include/parrot/dod.h */
  28
  29 /* HEADERIZER BEGIN: static */
  30
  31 static void trace_system_stack( PARROT_INTERP )
  32         __attribute__nonnull__(1);
  33
  34 /* HEADERIZER END: static */
  35
  36 #ifdef __ia64__
  37
  38 #  include <ucontext.h>
  39 extern void *flush_reg_store(void);
  40 #  define BACKING_STORE_BASE 0x80000fff80000000
  41
  42 #endif
  43
  44 /*
  45
  46 FUNCDOC: trace_system_areas
  47
  48 Traces the system stack and any additional CPU-specific areas.
  49
  50 */
  51
  52 void
  53 trace_system_areas(PARROT_INTERP)
  54 {
  55 #if defined(__sparc) /* Flush register windows */
  56     static union {
  57         unsigned int insns[4];
  58         double align_hack[2];
  59     } u = { {
  60 #  ifdef __sparcv9
  61                             0x81580000, /* flushw */
  62 #  else
  63                             0x91d02003, /* ta ST_FLUSH_WINDOWS */
  64 #  endif
  65                             0x81c3e008, /* retl */
  66                             0x01000000  /* nop */
  67     } };
  68
  69     static void (*fn_ptr)(void) = (void (*)(void))&u.align_hack[0];
  70     fn_ptr();
  71
  72 #elif defined(__ia64__)
  73
  74     struct ucontext ucp;
  75     void *current_regstore_top;
  76
  77     getcontext(&ucp);
  78     current_regstore_top = flush_reg_store();
  79
  80     trace_mem_block(interp, 0x80000fff80000000,
  81             (size_t)current_regstore_top);
  82 #else
  83
  84 #  ifdef PARROT_HAS_HEADER_SETJMP
  85     Parrot_jump_buff env;
  86
  87     /* Zero the Parrot_jump_buff, otherwise you will trace stale objects */
  88     memset(&env, 0, sizeof (env));
  89
  90     /* this should put registers in env, which then get marked in
  91      * trace_system_stack below
  92      */
  93     setjmp(env);
  94 #  endif
  95
  96 #endif
  97
  98
  99     trace_system_stack(interp);
 100 }
 101
 102 /*
 103
 104 FUNCDOC: trace_system_stack
 105
 106 Traces the memory block starting at C<< interp->lo_var_ptr >>.
 107
 108 */
 109
 110 static void
 111 trace_system_stack(PARROT_INTERP)
 112 {
 113     const size_t lo_var_ptr = (size_t)interp->lo_var_ptr;
 114
 115     trace_mem_block(interp, (size_t)lo_var_ptr,
 116             (size_t)&lo_var_ptr);
 117 }
 118
 119 /*
 120
 121 =head1 SEE ALSO
 122
 123 F<src/dod.c>, F<include/parrot/dod.h> and F<docs/infant.dev>.
 124
 125 */
 126
 127
 128 /*
 129  * Local variables:
 130  *   c-file-style: "parrot"
 131  * End:
 132  * vim: expandtab shiftwidth=4:
 133  */