-# We want to access the "PC" (Program Counter) register from a struct
-# ucontext. Every system has its own way of doing that. We try all the
-# possibilities we know about. Note REG_PC should come first (REG_RIP
-# is also defined on solaris, but does the wrong thing).
-AC_MSG_CHECKING([how to access the program counter from a struct ucontext])
-pc_fields=" uc_mcontext.gregs[[REG_PC]]" # Solaris x86 (32 + 64 bit)
-pc_fields="$pc_fields uc_mcontext.gregs[[REG_EIP]]" # Linux (i386)
-pc_fields="$pc_fields uc_mcontext.gregs[[REG_RIP]]" # Linux (x86_64)
-pc_fields="$pc_fields uc_mcontext.sc_ip" # Linux (ia64)
-pc_fields="$pc_fields uc_mcontext.uc_regs->gregs[[PT_NIP]]" # Linux (ppc)
-pc_fields="$pc_fields uc_mcontext.gregs[[R15]]" # Linux (arm old [untested])
-pc_fields="$pc_fields uc_mcontext.arm_pc" # Linux (arm new [untested])
-pc_fields="$pc_fields uc_mcontext.mc_eip" # FreeBSD (i386)
-pc_fields="$pc_fields uc_mcontext.mc_rip" # FreeBSD (x86_64 [untested])
-pc_fields="$pc_fields uc_mcontext->ss.eip" # OS X (i386, <=10.4)
-pc_fields="$pc_fields uc_mcontext->__ss.__eip" # OS X (i386, >=10.5)
-pc_fields="$pc_fields uc_mcontext->ss.rip" # OS X (x86_64)
-pc_fields="$pc_fields uc_mcontext->__ss.__rip" # OS X (>=10.5 [untested])
-pc_fields="$pc_fields uc_mcontext->ss.srr0" # OS X (ppc, ppc64 [untested])
-pc_fields="$pc_fields uc_mcontext->__ss.__srr0" # OS X (>=10.5 [untested])
-pc_field_found=false
-for pc_field in $pc_fields; do
- if ! $pc_field_found; then
- AC_TRY_COMPILE([#define _GNU_SOURCE 1
- #include <ucontext.h>],
- [ucontext_t u; return u.$pc_field == 0;],
- AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
- How to access the PC from a struct ucontext)
- AC_MSG_RESULT([$pc_field])
- pc_field_found=true)
- fi
-done
-if ! $pc_field_found; then
- AC_MSG_WARN(Could not find the PC. Will not output failed addresses...)
-fi