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Performance optimisations for fast trace.

Browse source 
Insert static branch prediction predicates in useful places and avoid
unnecessary code in the hottest paths. Bypass unnecessary indirect
calls, in particular to access_mem(), when known to be safe.
This commit is contained in:
Lassi Tuura 2011-04-17 20:33:09 -07:00 committed by Arun Sharma
parent e2962af9d3
commit ae5c1f2adf
10 changed files with 88 additions and 62 deletions
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8
include/libunwind_i.h
View file

@ -301,6 +301,14 @@ struct elf_image
size_t size; /* (file-) size of the image */ size_t size; /* (file-) size of the image */
}; };
/* Provide a place holder for architecture to override for fast access
to memory when known not to need to validate and know the access
will be local to the process. A suitable override will improve
unw_tdep_trace() performance in particular. */
#define ACCESS_MEM_FAST(ret,validate,cur,addr,to) \
do { (ret) = dwarf_get ((cur), DWARF_MEM_LOC ((cur), (addr)), &(to)); } \
while (0)
#include "tdep/libunwind_i.h" #include "tdep/libunwind_i.h"
#ifndef tdep_get_func_addr #ifndef tdep_get_func_addr

8
include/tdep-x86_64/libunwind_i.h
View file

@ -110,10 +110,10 @@ dwarf_get_uc(const struct dwarf_cursor *cursor)
# define DWARF_LOC(r, t) ((dwarf_loc_t) { .val = (r) }) # define DWARF_LOC(r, t) ((dwarf_loc_t) { .val = (r) })
# define DWARF_IS_REG_LOC(l) 0 # define DWARF_IS_REG_LOC(l) 0
# define DWARF_REG_LOC(c,r) (DWARF_LOC((unw_word_t) \ # define DWARF_REG_LOC(c,r) (DWARF_LOC((unw_word_t) \
tdep_uc_addr(dwarf_get_uc(c), (r)), 0)) x86_64_r_uc_addr(dwarf_get_uc(c), (r)), 0))
# define DWARF_MEM_LOC(c,m) DWARF_LOC ((m), 0) # define DWARF_MEM_LOC(c,m) DWARF_LOC ((m), 0)
# define DWARF_FPREG_LOC(c,r) (DWARF_LOC((unw_word_t) \ # define DWARF_FPREG_LOC(c,r) (DWARF_LOC((unw_word_t) \
tdep_uc_addr(dwarf_get_uc(c), (r)), 0)) x86_64_r_uc_addr(dwarf_get_uc(c), (r)), 0))
#else /* !UNW_LOCAL_ONLY */ #else /* !UNW_LOCAL_ONLY */
# define DWARF_LOC_TYPE_FP (1 << 0) # define DWARF_LOC_TYPE_FP (1 << 0)
@ -184,7 +184,6 @@ dwarf_put (struct dwarf_cursor *c, dwarf_loc_t loc, unw_word_t val)
/* Platforms that support UNW_INFO_FORMAT_TABLE need to define /* Platforms that support UNW_INFO_FORMAT_TABLE need to define
tdep_search_unwind_table. */ tdep_search_unwind_table. */
#define tdep_search_unwind_table dwarf_search_unwind_table #define tdep_search_unwind_table dwarf_search_unwind_table
#define tdep_uc_addr UNW_ARCH_OBJ(uc_addr)
#define tdep_get_elf_image UNW_ARCH_OBJ(get_elf_image) #define tdep_get_elf_image UNW_ARCH_OBJ(get_elf_image)
#define tdep_access_reg UNW_OBJ(access_reg) #define tdep_access_reg UNW_OBJ(access_reg)
#define tdep_access_fpreg UNW_OBJ(access_fpreg) #define tdep_access_fpreg UNW_OBJ(access_fpreg)
@ -199,6 +198,7 @@ dwarf_put (struct dwarf_cursor *c, dwarf_loc_t loc, unw_word_t val)
#endif #endif
#define tdep_stash_frame UNW_OBJ(stash_frame) #define tdep_stash_frame UNW_OBJ(stash_frame)
#define tdep_trace UNW_OBJ(tdep_trace) #define tdep_trace UNW_OBJ(tdep_trace)
#define x86_64_r_uc_addr UNW_OBJ(r_uc_addr)
#ifdef UNW_LOCAL_ONLY #ifdef UNW_LOCAL_ONLY
# define tdep_find_proc_info(c,ip,n) \ # define tdep_find_proc_info(c,ip,n) \
@ -226,7 +226,7 @@ extern void tdep_init_mem_validate (void);
extern int tdep_search_unwind_table (unw_addr_space_t as, unw_word_t ip, extern int tdep_search_unwind_table (unw_addr_space_t as, unw_word_t ip,
unw_dyn_info_t *di, unw_proc_info_t *pi, unw_dyn_info_t *di, unw_proc_info_t *pi,
int need_unwind_info, void *arg); int need_unwind_info, void *arg);
extern void *tdep_uc_addr (ucontext_t *uc, int reg); extern void *x86_64_r_uc_addr (ucontext_t *uc, int reg);
extern int tdep_get_elf_image (struct elf_image *ei, pid_t pid, unw_word_t ip, extern int tdep_get_elf_image (struct elf_image *ei, pid_t pid, unw_word_t ip,
unsigned long *segbase, unsigned long *mapoff, unsigned long *segbase, unsigned long *mapoff,
char *path, size_t pathlen); char *path, size_t pathlen);

6
src/mi/backtrace.c
View file

@ -39,7 +39,7 @@ slow_backtrace (void **buffer, int size, unw_context_t *uc)
unw_word_t ip; unw_word_t ip;
int n = 0; int n = 0;
if (unw_init_local (&cursor, uc) < 0) if (unlikely (unw_init_local (&cursor, uc) < 0))
return 0; return 0;
while (unw_step (&cursor) > 0) while (unw_step (&cursor) > 0)
@ -63,10 +63,10 @@ unw_backtrace (void **buffer, int size)
tdep_getcontext_trace (&uc); tdep_getcontext_trace (&uc);
if (unw_init_local (&cursor, &uc) < 0) if (unlikely (unw_init_local (&cursor, &uc) < 0))
return 0; return 0;
if (tdep_trace (&cursor, buffer, &n) < 0) if (unlikely (tdep_trace (&cursor, buffer, &n) < 0))
{ {
unw_getcontext (&uc); unw_getcontext (&uc);
return slow_backtrace (buffer, size, &uc); return slow_backtrace (buffer, size, &uc);

15
src/x86_64/Ginit.c
View file

@ -47,16 +47,6 @@ static struct unw_addr_space local_addr_space;
PROTECTED unw_addr_space_t unw_local_addr_space = &local_addr_space; PROTECTED unw_addr_space_t unw_local_addr_space = &local_addr_space;
# ifdef UNW_LOCAL_ONLY
HIDDEN void *
tdep_uc_addr (ucontext_t *uc, int reg)
{
return x86_64_r_uc_addr (uc, reg);
}
# endif /* UNW_LOCAL_ONLY */
HIDDEN unw_dyn_info_list_t _U_dyn_info_list; HIDDEN unw_dyn_info_list_t _U_dyn_info_list;
/* XXX fix me: there is currently no way to locate the dyn-info list /* XXX fix me: there is currently no way to locate the dyn-info list
@ -168,7 +158,7 @@ static int
access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write, access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write,
void *arg) void *arg)
{ {
if (write) if (unlikely (write))
{ {
Debug (16, "mem[%016lx] <- %lx\n", addr, *val); Debug (16, "mem[%016lx] <- %lx\n", addr, *val);
*(unw_word_t *) addr = *val; *(unw_word_t *) addr = *val;
@ -177,7 +167,8 @@ access_mem (unw_addr_space_t as, unw_word_t addr, unw_word_t *val, int write,
{ {
/* validate address */ /* validate address */
const struct cursor *c = (const struct cursor *)arg; const struct cursor *c = (const struct cursor *)arg;
if (c && c->validate && validate_mem(addr)) if (likely (c != 0) && unlikely (c->validate)
&& unlikely (validate_mem (addr)))
return -1; return -1;
*val = *(unw_word_t *) addr; *val = *(unw_word_t *) addr;
Debug (16, "mem[%016lx] -> %lx\n", addr, *val); Debug (16, "mem[%016lx] -> %lx\n", addr, *val);

2
src/x86_64/Ginit_local.c
View file

@ -43,7 +43,7 @@ unw_init_local (unw_cursor_t *cursor, ucontext_t *uc)
{ {
struct cursor *c = (struct cursor *) cursor; struct cursor *c = (struct cursor *) cursor;
if (tdep_needs_initialization) if (unlikely (tdep_needs_initialization))
tdep_init (); tdep_init ();
Debug (1, "(cursor=%p)\n", c); Debug (1, "(cursor=%p)\n", c);

1
src/x86_64/Gos-freebsd.c
View file

@ -154,6 +154,7 @@ unw_handle_signal_frame (unw_cursor_t *cursor)
HIDDEN void * HIDDEN void *
x86_64_r_uc_addr (ucontext_t *uc, int reg) x86_64_r_uc_addr (ucontext_t *uc, int reg)
{ {
/* NOTE: common_init() in init.h inlines these for fast path access. */
void *addr; void *addr;
switch (reg) switch (reg)

1
src/x86_64/Gos-linux.c
View file

@ -106,6 +106,7 @@ unw_handle_signal_frame (unw_cursor_t *cursor)
HIDDEN void * HIDDEN void *
x86_64_r_uc_addr (ucontext_t *uc, int reg) x86_64_r_uc_addr (ucontext_t *uc, int reg)
{ {
/* NOTE: common_init() in init.h inlines these for fast path access. */
void *addr; void *addr;
switch (reg) switch (reg)

49
src/x86_64/Gtrace.c
View file

@ -92,7 +92,7 @@ trace_cache_buckets (void)
unw_tdep_frame_t *frames = mempool_alloc(&trace_frame_pool); unw_tdep_frame_t *frames = mempool_alloc(&trace_frame_pool);
size_t i; size_t i;
if (likely (frames != 0)) if (likely(frames != 0))
for (i = 0; i < (1u << HASH_LOW_BITS); ++i) for (i = 0; i < (1u << HASH_LOW_BITS); ++i)
frames[i] = empty_frame; frames[i] = empty_frame;
@ -142,7 +142,7 @@ trace_cache_expand (unw_trace_cache_t *cache)
old_size = (1u << cache->log_frame_vecs); old_size = (1u << cache->log_frame_vecs);
new_size = cache->log_frame_vecs + 2; new_size = cache->log_frame_vecs + 2;
for (i = old_size; i < (1u << new_size); ++i) for (i = old_size; i < (1u << new_size); ++i)
if (unlikely (! (cache->frames[i] = trace_cache_buckets()))) if (unlikely(! (cache->frames[i] = trace_cache_buckets())))
{ {
Debug(5, "failed to expand cache to 2^%lu hash bucket sets\n", new_size); Debug(5, "failed to expand cache to 2^%lu hash bucket sets\n", new_size);
for (j = old_size; j < i; ++j) for (j = old_size; j < i; ++j)
@ -237,10 +237,10 @@ trace_init_addr (unw_tdep_frame_t *f,
d->loc[UNW_X86_64_RSP] = DWARF_REG_LOC (d, UNW_X86_64_RSP); d->loc[UNW_X86_64_RSP] = DWARF_REG_LOC (d, UNW_X86_64_RSP);
c->frame_info = *f; c->frame_info = *f;
if (dwarf_put (d, d->loc[UNW_X86_64_RIP], rip) >= 0 if (likely(dwarf_put (d, d->loc[UNW_X86_64_RIP], rip) >= 0)
&& dwarf_put (d, d->loc[UNW_X86_64_RBP], rbp) >= 0 && likely(dwarf_put (d, d->loc[UNW_X86_64_RBP], rbp) >= 0)
&& dwarf_put (d, d->loc[UNW_X86_64_RSP], rsp) >= 0 && likely(dwarf_put (d, d->loc[UNW_X86_64_RSP], rsp) >= 0)
&& (ret = unw_step (cursor)) >= 0) && likely((ret = unw_step (cursor)) >= 0))
*f = c->frame_info; *f = c->frame_info;
/* If unw_step() stopped voluntarily, remember that, even if it /* If unw_step() stopped voluntarily, remember that, even if it
@ -290,14 +290,14 @@ trace_lookup (unw_cursor_t *cursor,
addr = frame->virtual_address; addr = frame->virtual_address;
/* Return if we found the address. */ /* Return if we found the address. */
if (addr == rip) if (likely(addr == rip))
{ {
Debug (4, "found address after %ld steps\n", i); Debug (4, "found address after %ld steps\n", i);
return frame; return frame;
} }
/* If slot is empty, reuse it. */ /* If slot is empty, reuse it. */
if (! addr) if (likely(! addr))
break; break;
/* Linear probe to next slot candidate, step = 1. */ /* Linear probe to next slot candidate, step = 1. */
@ -310,9 +310,9 @@ trace_lookup (unw_cursor_t *cursor,
it's free or collides. Note that hash expansion drops previous it's free or collides. Note that hash expansion drops previous
contents; further lookups will refill the hash. */ contents; further lookups will refill the hash. */
Debug (4, "updating slot %lu after %ld steps, replacing 0x%lx\n", slot, i, addr); Debug (4, "updating slot %lu after %ld steps, replacing 0x%lx\n", slot, i, addr);
if (unlikely (addr || cache->used >= cache_size / 2)) if (unlikely(addr || cache->used >= cache_size / 2))
{ {
if (unlikely (trace_cache_expand (cache) < 0)) if (unlikely(trace_cache_expand (cache) < 0))
return 0; return 0;
cache_size = 1u << (HASH_LOW_BITS + cache->log_frame_vecs); cache_size = 1u << (HASH_LOW_BITS + cache->log_frame_vecs);
@ -404,7 +404,7 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
int ret; int ret;
/* Check input parametres. */ /* Check input parametres. */
if (! cursor || ! buffer || ! size || (maxdepth = *size) <= 0) if (unlikely(! cursor || ! buffer || ! size || (maxdepth = *size) <= 0))
return -UNW_EINVAL; return -UNW_EINVAL;
Debug (1, "begin ip 0x%lx cfa 0x%lx\n", d->ip, d->cfa); Debug (1, "begin ip 0x%lx cfa 0x%lx\n", d->ip, d->cfa);
@ -415,7 +415,7 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
/* Determine initial register values. */ /* Determine initial register values. */
rip = d->ip; rip = d->ip;
rsp = cfa = d->cfa; rsp = cfa = d->cfa;
if ((ret = dwarf_get (d, d->loc[UNW_X86_64_RBP], &rbp)) < 0) if (unlikely((ret = dwarf_get (d, d->loc[UNW_X86_64_RBP], &rbp)) < 0))
{ {
Debug (1, "returning %d, rbp value not found\n", ret); Debug (1, "returning %d, rbp value not found\n", ret);
*size = 0; *size = 0;
@ -424,7 +424,7 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
} }
/* Get frame cache. */ /* Get frame cache. */
if (! (cache = trace_cache_get())) if (unlikely(! (cache = trace_cache_get())))
{ {
Debug (1, "returning %d, cannot get trace cache\n", -UNW_ENOMEM); Debug (1, "returning %d, cannot get trace cache\n", -UNW_ENOMEM);
*size = 0; *size = 0;
@ -450,7 +450,7 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
unw_tdep_frame_t *f = trace_lookup (cursor, cache, cfa, rip, rbp, rsp); unw_tdep_frame_t *f = trace_lookup (cursor, cache, cfa, rip, rbp, rsp);
/* If we don't have information for this frame, give up. */ /* If we don't have information for this frame, give up. */
if (! f) if (unlikely(! f))
{ {
ret = -UNW_ENOINFO; ret = -UNW_ENOINFO;
break; break;
@ -481,9 +481,9 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
case UNW_X86_64_FRAME_STANDARD: case UNW_X86_64_FRAME_STANDARD:
/* Advance standard traceable frame. */ /* Advance standard traceable frame. */
cfa = (f->cfa_reg_rsp ? rsp : rbp) + f->cfa_reg_offset; cfa = (f->cfa_reg_rsp ? rsp : rbp) + f->cfa_reg_offset;
ret = dwarf_get (d, DWARF_MEM_LOC (d, cfa - 8), &rip); ACCESS_MEM_FAST(ret, c->validate, d, cfa - 8, rip);
if (ret >= 0 && f->rbp_cfa_offset != -1) if (likely(ret >= 0) && likely(f->rbp_cfa_offset != -1))
ret = dwarf_get (d, DWARF_MEM_LOC (d, cfa + f->rbp_cfa_offset), &rbp); ACCESS_MEM_FAST(ret, c->validate, d, cfa + f->rbp_cfa_offset, rbp);
/* Don't bother reading RSP from DWARF, CFA becomes new RSP. */ /* Don't bother reading RSP from DWARF, CFA becomes new RSP. */
rsp = cfa; rsp = cfa;
@ -497,13 +497,12 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
registers (ucontext) among other things. We know the info registers (ucontext) among other things. We know the info
is stored at some unknown constant offset off inner frame's is stored at some unknown constant offset off inner frame's
CFA. We determine the actual offset from DWARF unwind info. */ CFA. We determine the actual offset from DWARF unwind info. */
d->use_prev_instr = 0;
cfa = cfa + f->cfa_reg_offset; cfa = cfa + f->cfa_reg_offset;
ret = dwarf_get (d, DWARF_MEM_LOC (d, cfa + f->rbp_cfa_offset + dRIP), &rip); ACCESS_MEM_FAST(ret, c->validate, d, cfa + f->rbp_cfa_offset + dRIP, rip);
if (ret >= 0) if (likely(ret >= 0))
ret = dwarf_get (d, DWARF_MEM_LOC (d, cfa + f->rbp_cfa_offset), &rbp); ACCESS_MEM_FAST(ret, c->validate, d, cfa + f->rbp_cfa_offset, rbp);
if (ret >= 0) if (likely(ret >= 0))
ret = dwarf_get (d, DWARF_MEM_LOC (d, cfa + f->rsp_cfa_offset), &rsp); ACCESS_MEM_FAST(ret, c->validate, d, cfa + f->rsp_cfa_offset, rsp);
/* Resume stack at signal restoration point. The stack is not /* Resume stack at signal restoration point. The stack is not
necessarily continuous here, especially with sigaltstack(). */ necessarily continuous here, especially with sigaltstack(). */
@ -524,8 +523,8 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *size)
Debug (4, "new cfa 0x%lx rip 0x%lx rsp 0x%lx rbp 0x%lx\n", Debug (4, "new cfa 0x%lx rip 0x%lx rsp 0x%lx rbp 0x%lx\n",
cfa, rip, rsp, rbp); cfa, rip, rsp, rbp);
/* If we failed on ended up somewhere bogus, stop. */ /* If we failed or ended up somewhere bogus, stop. */
if (ret < 0 || rip < 0x4000) if (unlikely(ret < 0 || rip < 0x4000))
break; break;
/* Record this address in stack trace. We skipped the first address. */ /* Record this address in stack trace. We skipped the first address. */

48
src/x86_64/init.h
View file

@ -27,28 +27,42 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include "unwind_i.h" #include "unwind_i.h"
/* Avoid a trip to x86_64_r_uc_addr() for purely local initialisation. */
#if defined UNW_LOCAL_ONLY && defined __linux
# define REG_INIT_LOC(c, rlc, ruc) \
DWARF_LOC ((unw_word_t) &c->uc->uc_mcontext.gregs[REG_ ## ruc], 0)
#elif defined UNW_LOCAL_ONLY && defined __FreeBSD__
# define REG_INIT_LOC(c, rlc, ruc) \
DWARF_LOC ((unw_word_t) &c->uc->uc_mcontext.mc_ ## rlc, 0)
#else
# define REG_INIT_LOC(c, rlc, ruc) \
DWARF_REG_LOC (&c->dwarf, UNW_X86_64_ ## ruc)
#endif
static inline int static inline int
common_init (struct cursor *c, unsigned use_prev_instr) common_init (struct cursor *c, unsigned use_prev_instr)
{ {
int ret; int ret;
c->dwarf.loc[RAX] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RAX); c->dwarf.loc[RAX] = REG_INIT_LOC(c, rax, RAX);
c->dwarf.loc[RDX] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RDX); c->dwarf.loc[RDX] = REG_INIT_LOC(c, rdx, RDX);
c->dwarf.loc[RCX] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RCX); c->dwarf.loc[RCX] = REG_INIT_LOC(c, rcx, RCX);
c->dwarf.loc[RBX] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RBX); c->dwarf.loc[RBX] = REG_INIT_LOC(c, rbx, RBX);
c->dwarf.loc[RSI] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RSI); c->dwarf.loc[RSI] = REG_INIT_LOC(c, rsi, RSI);
c->dwarf.loc[RDI] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RDI); c->dwarf.loc[RDI] = REG_INIT_LOC(c, rdi, RDI);
c->dwarf.loc[RBP] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RBP); c->dwarf.loc[RBP] = REG_INIT_LOC(c, rbp, RBP);
c->dwarf.loc[RSP] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RSP); c->dwarf.loc[RSP] = REG_INIT_LOC(c, rsp, RSP);
c->dwarf.loc[R8] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R8); c->dwarf.loc[R8] = REG_INIT_LOC(c, r8, R8);
c->dwarf.loc[R9] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R9); c->dwarf.loc[R9] = REG_INIT_LOC(c, r9, R9);
c->dwarf.loc[R10] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R10); c->dwarf.loc[R10] = REG_INIT_LOC(c, r10, R10);
c->dwarf.loc[R11] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R11); c->dwarf.loc[R11] = REG_INIT_LOC(c, r11, R11);
c->dwarf.loc[R12] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R12); c->dwarf.loc[R12] = REG_INIT_LOC(c, r12, R12);
c->dwarf.loc[R13] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R13); c->dwarf.loc[R13] = REG_INIT_LOC(c, r13, R13);
c->dwarf.loc[R14] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R14); c->dwarf.loc[R14] = REG_INIT_LOC(c, r14, R14);
c->dwarf.loc[R15] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_R15); c->dwarf.loc[R15] = REG_INIT_LOC(c, r15, R15);
c->dwarf.loc[RIP] = DWARF_REG_LOC (&c->dwarf, UNW_X86_64_RIP); c->dwarf.loc[RIP] = REG_INIT_LOC(c, rip, RIP);
ret = dwarf_get (&c->dwarf, c->dwarf.loc[RIP], &c->dwarf.ip); ret = dwarf_get (&c->dwarf, c->dwarf.loc[RIP], &c->dwarf.ip);
if (ret < 0) if (ret < 0)

12
src/x86_64/unwind_i.h
View file

@ -65,6 +65,18 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#define x86_64_r_uc_addr UNW_OBJ(r_uc_addr) #define x86_64_r_uc_addr UNW_OBJ(r_uc_addr)
#define x86_64_sigreturn UNW_OBJ(sigreturn) #define x86_64_sigreturn UNW_OBJ(sigreturn)
/* By-pass calls to access_mem() when known to be safe. */
#ifdef UNW_LOCAL_ONLY
# undef ACCESS_MEM_FAST
# define ACCESS_MEM_FAST(ret,validate,cur,addr,to) \
do { \
if (unlikely(validate)) \
(ret) = dwarf_get ((cur), DWARF_MEM_LOC ((cur), (addr)), &(to)); \
else \
(ret) = 0, (to) = *(unw_word_t *)(addr); \
} while (0)
#endif
extern void x86_64_local_addr_space_init (void); extern void x86_64_local_addr_space_init (void);
extern int x86_64_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, extern int x86_64_local_resume (unw_addr_space_t as, unw_cursor_t *cursor,
void *arg); void *arg);