/*
* ut_dump_backtrace -- dump stacktrace to error log using libunwind
*/
void
ut_dump_backtrace(void)
{
unw_context_t context;
unw_proc_info_t pip;
pip.unwind_info = NULL;
int ret = unw_getcontext(&context);
if (ret) {
ERR("unw_getcontext: %s [%d]", unw_strerror(ret), ret);
return;
}
unw_cursor_t cursor;
ret = unw_init_local(&cursor, &context);
if (ret) {
ERR("unw_init_local: %s [%d]", unw_strerror(ret), ret);
return;
}
ret = unw_step(&cursor);
char procname[PROCNAMELEN];
unsigned i = 0;
while (ret > 0) {
ret = unw_get_proc_info(&cursor, &pip);
if (ret) {
ERR("unw_get_proc_info: %s [%d]", unw_strerror(ret),
ret);
break;
}
unw_word_t off;
ret = unw_get_proc_name(&cursor, procname, PROCNAMELEN, &off);
if (ret && ret != -UNW_ENOMEM) {
if (ret != -UNW_EUNSPEC) {
ERR("unw_get_proc_name: %s [%d]",
unw_strerror(ret), ret);
}
strcpy(procname, "?");
}
void *ptr = (void *)(pip.start_ip + off);
Dl_info dlinfo;
const char *fname = "?";
if (dladdr(ptr, &dlinfo) && dlinfo.dli_fname &&
*dlinfo.dli_fname)
fname = dlinfo.dli_fname;
ERR("%u: %s (%s%s+0x%lx) [%p]", i++, fname, procname,
ret == -UNW_ENOMEM ? "..." : "", off, ptr);
ret = unw_step(&cursor);
if (ret < 0)
ERR("unw_step: %s [%d]", unw_strerror(ret), ret);
}
}
// Find LSDA and start address for a function at address controlPC
bool FindProcInfo(UIntNative controlPC, UIntNative* startAddress, UIntNative* lsda)
{
#ifndef CAN_LINK_SHARED_LIBUNWIND
return false;
#else // CAN_LINK_SHARED_LIBUNWIND
unw_context_t unwContext;
unw_cursor_t cursor;
REGDISPLAY regDisplay;
memset(®Display, 0, sizeof(REGDISPLAY));
regDisplay.SetIP((PCODE)controlPC);
if (!InitializeUnwindContextAndCursor(®Display, &cursor, &unwContext))
{
return false;
}
unw_proc_info_t procInfo;
int st = unw_get_proc_info(&cursor, &procInfo);
if (st < 0)
{
return false;
}
assert((procInfo.start_ip <= controlPC) && (controlPC < procInfo.end_ip));
*lsda = procInfo.lsda;
*startAddress = procInfo.start_ip;
return true;
#endif // CAN_LINK_SHARED_LIBUNWIND
}
void collectStackRoots(TraceStack *stack) {
unw_cursor_t cursor;
unw_context_t uc;
unw_word_t ip, sp, bp;
// force callee-save registers onto the stack:
// Actually, I feel like this is pretty brittle:
// collectStackRoots itself is allowed to save the callee-save registers
// on its own stack.
jmp_buf registers __attribute__((aligned(sizeof(void*))));
#ifdef VALGRIND
memset(®isters, 0, sizeof(registers));
memset(&cursor, 0, sizeof(cursor));
memset(&uc, 0, sizeof(uc));
memset(&ip, 0, sizeof(ip));
memset(&sp, 0, sizeof(sp));
memset(&bp, 0, sizeof(bp));
#endif
setjmp(registers);
assert(sizeof(registers) % 8 == 0);
//void* stack_bottom = __builtin_frame_address(0);
collectRoots(®isters, ®isters + 1, stack);
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
TraceStackGCVisitor visitor(stack);
int code;
while (true) {
int code = unw_step(&cursor);
assert(code > 0 && "something broke unwinding!");
unw_get_reg(&cursor, UNW_REG_IP, &ip);
unw_get_reg(&cursor, UNW_REG_SP, &sp);
unw_get_reg(&cursor, UNW_TDEP_BP, &bp);
void* cur_sp = (void*)sp;
void* cur_bp = (void*)bp;
//std::string name = g.func_addr_registry.getFuncNameAtAddress((void*)ip, true);
//if (VERBOSITY()) printf("ip = %lx (%s), stack = [%p, %p)\n", (long) ip, name.c_str(), cur_sp, cur_bp);
unw_proc_info_t pip;
unw_get_proc_info(&cursor, &pip);
if (pip.start_ip == (uintptr_t)&__libc_start_main) {
break;
}
if (pip.start_ip == (intptr_t)interpretFunction) {
// TODO Do we still need to crawl the interpreter itself?
gatherInterpreterRootsForFrame(&visitor, cur_bp);
}
collectRoots(cur_sp, (char*)cur_bp, stack);
}
}
PROTECTED unsigned long
_Unwind_GetRegionStart (struct _Unwind_Context *context)
{
unw_proc_info_t pi;
pi.start_ip = 0;
unw_get_proc_info (&context->cursor, &pi);
return pi.start_ip;
}
PROTECTED unsigned long
_Unwind_GetDataRelBase (struct _Unwind_Context *context)
{
unw_proc_info_t pi;
pi.gp = 0;
unw_get_proc_info (&context->cursor, &pi);
return pi.gp;
}
void
jffi_longjmp (jmp_buf env, int val)
{
extern int _jffi_longjmp_cont;
unw_context_t uc;
unw_cursor_t c;
unw_word_t sp, ip, bp = 0;
uintptr_t *wp = (uintptr_t *) env;
int i, setjmp_frame;
if (unw_getcontext (&uc) < 0 || unw_init_local (&c, &uc) < 0) {
debug("failed to get context");
abort ();
}
#ifdef __x86_86__
# define UNW_REG_BP UNW_X86_64_RBP
#else
# define UNW_REG_BP UNW_X86_EBP
#endif
setjmp_frame = 0;
do {
char name[256];
unw_proc_info_t pi;
unw_word_t off;
if (unw_get_reg (&c, UNW_REG_BP, &bp) < 0) {
abort();
}
if (unw_get_reg (&c, UNW_REG_SP, &sp) < 0) {
abort();
}
if (unw_get_reg (&c, UNW_REG_IP, &ip) < 0) {
abort();
}
unw_get_proc_name(&c, name, sizeof(name), &off);
unw_get_proc_info(&c, &pi);
// debug("frame %s ip=%llx sp=%llx bp=%llx wp[RP]=%p wp[SP]=%p, pi.start_ip=%llx, pi.end_ip=%llx",
// name, (long long) ip, (long long) sp, (long long) bp, (void *) wp[JB_RP], (void *) wp[JB_SP],
// pi.start_ip, pi.end_ip);
if (wp[JB_SP] > sp || wp[JB_RP] < pi.start_ip || wp[JB_RP] > pi.end_ip) continue;
/* found the right frame: */
// debug("found frame to jump back to");
assert (UNW_NUM_EH_REGS >= 2);
if (unw_set_reg (&c, UNW_REG_EH + 0, wp[JB_RP]) < 0
|| unw_set_reg (&c, UNW_REG_EH + 1, val) < 0
|| unw_set_reg (&c, UNW_REG_IP, (unw_word_t) (uintptr_t) &_jffi_longjmp_cont))
abort ();
unw_resume (&c);
// should not reach here
abort ();
} while (unw_step (&c) > 0);
// debug("failed to find correct frame to jmp to");
}
//
// Called by personality handler during phase 2 to find the start of the function
//
EXPORT uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context* context)
{
unw_cursor_t* cursor = (unw_cursor_t*)context;
unw_proc_info_t frameInfo;
uintptr_t result = 0;
if ( unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS )
result = frameInfo.start_ip;
DEBUG_PRINT_API("_Unwind_GetRegionStart(context=%p) => 0x%lX\n", context, result);
return result;
}
/// Called by personality handler during phase 2 to find the start of the
/// function.
_LIBUNWIND_EXPORT uintptr_t
_Unwind_GetRegionStart(struct _Unwind_Context *context) {
unw_cursor_t *cursor = (unw_cursor_t *)context;
unw_proc_info_t frameInfo;
uintptr_t result = 0;
if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS)
result = (uintptr_t)frameInfo.start_ip;
_LIBUNWIND_TRACE_API("_Unwind_GetRegionStart(context=%p) => 0x%" PRIXPTR "\n",
context, result);
return result;
}
//
// Called by personality handler during phase 2 to get LSDA for current frame
//
EXPORT uintptr_t _Unwind_GetLanguageSpecificData(struct _Unwind_Context* context)
{
unw_cursor_t* cursor = (unw_cursor_t*)context;
unw_proc_info_t frameInfo;
uintptr_t result = 0;
if ( unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS )
result = frameInfo.lsda;
DEBUG_PRINT_API("_Unwind_GetLanguageSpecificData(context=%p) => 0x%lX\n", context, result);
if ( result != 0 ) {
if ( *((uint8_t*)result) != 0xFF )
DEBUG_MESSAGE("lsda at 0x%lX does not start with 0xFF\n", result);
}
return result;
}
/// Called by personality handler during phase 2 to get LSDA for current frame.
_LIBUNWIND_EXPORT uintptr_t
_Unwind_GetLanguageSpecificData(struct _Unwind_Context *context) {
unw_cursor_t *cursor = (unw_cursor_t *)context;
unw_proc_info_t frameInfo;
uintptr_t result = 0;
if (unw_get_proc_info(cursor, &frameInfo) == UNW_ESUCCESS)
result = (uintptr_t)frameInfo.lsda;
_LIBUNWIND_TRACE_API("_Unwind_GetLanguageSpecificData(context=%p)"
"=> 0x%" PRIXPTR "\n", context, result);
if (result != 0) {
if (*((uint8_t *)result) != 0xFF)
_LIBUNWIND_DEBUG_LOG("lsda at 0x%" PRIXPTR " does not start with 0xFF\n", result);
}
return result;
}
/// Scans unwind information to find the function that contains the
/// specified code address "pc".
_LIBUNWIND_EXPORT void *_Unwind_FindEnclosingFunction(void *pc) {
_LIBUNWIND_TRACE_API("_Unwind_FindEnclosingFunction(pc=%p)\n", pc);
// This is slow, but works.
// We create an unwind cursor then alter the IP to be pc
unw_cursor_t cursor;
unw_context_t uc;
unw_proc_info_t info;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(long) pc);
if (unw_get_proc_info(&cursor, &info) == UNW_ESUCCESS)
return (void *)(long) info.start_ip;
else
return NULL;
}
void
fill_in_backtrace(FaultData* fdp)
{
unw_context_t uc;
unw_cursor_t c;
int i, boff;
memset(&uc, 0, sizeof(uc));
memset(&c, 0, sizeof(c));
if (unw_getcontext(&uc) < 0) {
abort();
}
if (unw_init_local(&c, &uc) < 0) {
abort();
}
// Skip the signal handler, and the signal trampoline
for (i = 0; i < SKIP_FRAME_COUNT; i++) {
if (unw_step(&c) <= 0) {
break;
}
}
memset(fdp->frame, 0, sizeof(fdp->frame));
fdp->frame_count = 0;
boff = 0;
do {
char fn[256];
unw_word_t off, ip;
Dl_info dli;
unw_proc_info_t pi;
unw_get_reg (&c, UNW_REG_IP, &ip);
fdp->frame[fdp->frame_count].addr = (uintptr_t) ip;
fdp->frame[fdp->frame_count].procname = (uintptr_t) &fdp->backtrace_buf[boff];
unw_get_proc_name(&c, (char *) fdp->frame[fdp->frame_count].procname, sizeof(fdp->backtrace_buf) - boff, &off);
unw_get_proc_info(&c, &pi);
boff += strlen((char *) fdp->frame[fdp->frame_count].procname) + 1;
fdp->frame[fdp->frame_count].libname = (uintptr_t) &fdp->backtrace_buf[boff];
dladdr((void *)(uintptr_t) ip, &dli);
strcpy((char *) (uintptr_t) fdp->frame[fdp->frame_count].libname, dli.dli_fname);
boff += strlen((char *) fdp->frame[fdp->frame_count].libname) + 1;
fdp->frame_count++;
} while (unw_step(&c) > 0);
}
G_GNUC_UNUSED static void
print_ctx (MonoContext *ctx)
{
char name[256];
unw_word_t off, ip, sp;
unw_proc_info_t pi;
int res;
unw_get_proc_name (&ctx->cursor, name, 256, &off);
unw_get_proc_info(&ctx->cursor, &pi);
res = unw_get_reg (&ctx->cursor, UNW_IA64_IP, &ip);
g_assert (res == 0);
res = unw_get_reg (&ctx->cursor, UNW_IA64_SP, &sp);
g_assert (res == 0);
printf ("%s:%lx [%lx-%lx] SP: %lx\n", name, ip - pi.start_ip, pi.start_ip, pi.end_ip, sp);
}
void zmq::print_backtrace (void)
{
static zmq::mutex_t mtx;
mtx.lock ();
Dl_info dl_info;
unw_cursor_t cursor;
unw_context_t ctx;
unsigned frame_n = 0;
unw_getcontext (&ctx);
unw_init_local (&cursor, &ctx);
while (unw_step (&cursor) > 0) {
unw_word_t offset;
unw_proc_info_t p_info;
const char *file_name;
char *demangled_name;
char func_name[256] = "";
void *addr;
int rc;
if (unw_get_proc_info (&cursor, &p_info))
break;
addr = (void *)(p_info.start_ip + offset);
if (dladdr (addr, &dl_info) && dl_info.dli_fname)
file_name = dl_info.dli_fname;
else
file_name = "?";
rc = unw_get_proc_name (&cursor, func_name, 256, &offset);
if (rc == -UNW_ENOINFO)
strcpy(func_name, "?");
demangled_name = abi::__cxa_demangle (func_name, NULL, NULL, &rc);
printf ("#%u %p in %s (%s+0x%lx)\n", frame_n++, addr, file_name,
rc ? func_name : demangled_name, (unsigned long) offset);
free (demangled_name);
}
puts ("");
fflush (stdout);
mtx.unlock ();
}
void unwindExc(Box* exc_obj) {
unw_cursor_t cursor;
unw_context_t uc;
unw_word_t ip, sp;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
int code;
unw_proc_info_t pip;
while (unw_step(&cursor) > 0) {
unw_get_reg(&cursor, UNW_REG_IP, &ip);
unw_get_reg(&cursor, UNW_REG_SP, &sp);
printf("ip = %lx, sp = %lx\n", (long)ip, (long)sp);
code = unw_get_proc_info(&cursor, &pip);
RELEASE_ASSERT(code == 0, "");
// printf("%lx %lx %lx %lx %lx %lx %d %d %p\n", pip.start_ip, pip.end_ip, pip.lsda, pip.handler, pip.gp,
// pip.flags, pip.format, pip.unwind_info_size, pip.unwind_info);
assert((pip.lsda == 0) == (pip.handler == 0));
assert(pip.flags == 0);
if (pip.handler == 0) {
if (VERBOSITY())
printf("Skipping frame without handler\n");
continue;
}
printf("%lx %lx %lx\n", pip.lsda, pip.handler, pip.flags);
// assert(pip.handler == (uintptr_t)__gxx_personality_v0 || pip.handler == (uintptr_t)__py_personality_v0);
// auto handler_fn = (int (*)(int, int, uint64_t, void*, void*))pip.handler;
////handler_fn(1, 1 /* _UA_SEARCH_PHASE */, 0 /* exc_class */, NULL, NULL);
// handler_fn(2, 2 /* _UA_SEARCH_PHASE */, 0 /* exc_class */, NULL, NULL);
unw_set_reg(&cursor, UNW_REG_IP, 1);
// TODO testing:
// unw_resume(&cursor);
}
abort();
}
/// Find dwarf unwind info for an address 'pc' in some function.
_LIBUNWIND_EXPORT const void *_Unwind_Find_FDE(const void *pc,
struct dwarf_eh_bases *bases) {
// This is slow, but works.
// We create an unwind cursor then alter the IP to be pc
unw_cursor_t cursor;
unw_context_t uc;
unw_proc_info_t info;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(long) pc);
unw_get_proc_info(&cursor, &info);
bases->tbase = (uintptr_t)info.extra;
bases->dbase = 0; // dbase not used on Mac OS X
bases->func = (uintptr_t)info.start_ip;
_LIBUNWIND_TRACE_API("_Unwind_Find_FDE(pc=%p) => %p\n", pc,
(void *)(long) info.unwind_info);
return (void *)(long) info.unwind_info;
}
static std::vector<const LineInfo*> getTracebackEntries() {
std::vector<const LineInfo*> entries;
unw_cursor_t cursor;
unw_context_t uc;
unw_word_t ip, bp;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
int code;
unw_proc_info_t pip;
while (unw_step(&cursor) > 0) {
unw_get_reg(&cursor, UNW_REG_IP, &ip);
const LineInfo* line = getLineInfoFor((uint64_t)ip);
if (line) {
entries.push_back(line);
} else {
unw_get_reg(&cursor, UNW_TDEP_BP, &bp);
unw_proc_info_t pip;
code = unw_get_proc_info(&cursor, &pip);
RELEASE_ASSERT(code == 0, "%d", code);
if (pip.start_ip == (intptr_t)interpretFunction) {
line = getLineInfoForInterpretedFrame((void*)bp);
assert(line);
entries.push_back(line);
}
}
}
std::reverse(entries.begin(), entries.end());
return entries;
}
void
debug_backtrace_capture(struct debug_stack_frame *backtrace,
unsigned start_frame,
unsigned nr_frames)
{
unw_cursor_t cursor;
unw_context_t context;
unw_proc_info_t pip;
unsigned i = 0;
pip.unwind_info = NULL;
unw_getcontext(&context);
unw_init_local(&cursor, &context);
while ((start_frame > 0) && (unw_step(&cursor) > 0))
start_frame--;
while ((i < nr_frames) && (unw_step(&cursor) > 0)) {
unw_word_t ip;
unw_get_reg(&cursor, UNW_REG_IP, &ip);
unw_get_proc_info(&cursor, &pip);
backtrace[i].start_ip = pip.start_ip;
backtrace[i].off = ip - pip.start_ip;
backtrace[i].procname = symbol_name_cached(&cursor, &pip);
i++;
}
while (i < nr_frames) {
backtrace[i].start_ip = 0;
i++;
}
}
int
main(int argc UNUSED, char **argv)
{
unw_addr_space_t as;
struct UCD_info *ui;
unw_cursor_t c;
int ret;
#define TEST_FRAMES 4
#define TEST_NAME_LEN 32
int testcase = 0;
int test_cur = 0;
long test_start_ips[TEST_FRAMES];
char test_names[TEST_FRAMES][TEST_NAME_LEN];
install_sigsegv_handler();
const char *progname = strrchr(argv[0], '/');
if (progname)
progname++;
else
progname = argv[0];
if (!argv[1])
error_msg_and_die("Usage: %s COREDUMP [VADDR:BINARY_FILE]...", progname);
msg_prefix = progname;
as = unw_create_addr_space(&_UCD_accessors, 0);
if (!as)
error_msg_and_die("unw_create_addr_space() failed");
ui = _UCD_create(argv[1]);
if (!ui)
error_msg_and_die("_UCD_create('%s') failed", argv[1]);
ret = unw_init_remote(&c, as, ui);
if (ret < 0)
error_msg_and_die("unw_init_remote() failed: ret=%d\n", ret);
argv += 2;
/* Enable checks for the crasher test program? */
if (*argv && !strcmp(*argv, "-testcase"))
{
testcase = 1;
logmode = LOGMODE_NONE;
argv++;
}
while (*argv)
{
char *colon;
unsigned long vaddr = strtoul(*argv, &colon, 16);
if (*colon != ':')
error_msg_and_die("Bad format: '%s'", *argv);
if (_UCD_add_backing_file_at_vaddr(ui, vaddr, colon + 1) < 0)
error_msg_and_die("Can't add backing file '%s'", colon + 1);
argv++;
}
for (;;)
{
unw_word_t ip;
ret = unw_get_reg(&c, UNW_REG_IP, &ip);
if (ret < 0)
error_msg_and_die("unw_get_reg(UNW_REG_IP) failed: ret=%d\n", ret);
unw_proc_info_t pi;
ret = unw_get_proc_info(&c, &pi);
if (ret < 0)
error_msg_and_die("unw_get_proc_info(ip=0x%lx) failed: ret=%d\n", (long) ip, ret);
if (!testcase)
printf("\tip=0x%08lx proc=%08lx-%08lx handler=0x%08lx lsda=0x%08lx\n",
(long) ip,
(long) pi.start_ip, (long) pi.end_ip,
(long) pi.handler, (long) pi.lsda);
if (testcase && test_cur < TEST_FRAMES)
{
unw_word_t off;
test_start_ips[test_cur] = (long) pi.start_ip;
if (unw_get_proc_name(&c, test_names[test_cur], sizeof(test_names[0]), &off) != 0)
{
test_names[test_cur][0] = '\0';
}
test_cur++;
}
log("step");
ret = unw_step(&c);
log("step done:%d", ret);
if (ret < 0)
error_msg_and_die("FAILURE: unw_step() returned %d", ret);
if (ret == 0)
break;
}
log("stepping ended");
/* Check that the second and third frames are equal, but distinct of the
* others */
if (testcase &&
(test_cur != 4
|| test_start_ips[1] != test_start_ips[2]
|| test_start_ips[0] == test_start_ips[1]
|| test_start_ips[2] == test_start_ips[3]
)
)
{
fprintf(stderr, "FAILURE: start IPs incorrect\n");
return -1;
}
if (testcase &&
( strcmp(test_names[0], "a")
|| strcmp(test_names[1], "b")
|| strcmp(test_names[2], "b")
|| strcmp(test_names[3], "main")
)
)
{
fprintf(stderr, "FAILURE: procedure names are missing/incorrect\n");
return -1;
}
_UCD_destroy(ui);
unw_destroy_addr_space(as);
return 0;
}
PROTECTED _Unwind_Reason_Code
_Unwind_RaiseException (struct _Unwind_Exception *exception_object)
{
uint64_t exception_class = exception_object->exception_class;
_Unwind_Personality_Fn personality;
struct _Unwind_Context context;
_Unwind_Reason_Code reason;
unw_proc_info_t pi;
unw_context_t uc;
unw_word_t ip;
int ret;
if (_Unwind_InitContext (&context, &uc) < 0)
return _URC_FATAL_PHASE1_ERROR;
Debug (1, "(exception_object=%p)\n", exception_object);
/* Phase 1 (search phase) */
while (1)
{
if ((ret = unw_step (&context.cursor)) <= 0)
{
if (ret == 0)
{
Debug (1, "no handler found\n");
return _URC_END_OF_STACK;
}
else
return _URC_FATAL_PHASE1_ERROR;
}
if (unw_get_proc_info (&context.cursor, &pi) < 0)
return _URC_FATAL_PHASE1_ERROR;
personality = (_Unwind_Personality_Fn) (uintptr_t) pi.handler;
if (personality)
{
reason = (*personality) (_U_VERSION, _UA_SEARCH_PHASE,
exception_class, exception_object,
&context);
if (reason != _URC_CONTINUE_UNWIND)
{
if (reason == _URC_HANDLER_FOUND)
break;
else
{
Debug (1, "personality returned %d\n", reason);
return _URC_FATAL_PHASE1_ERROR;
}
}
}
}
/* Exceptions are associated with IP-ranges. If a given exception
is handled at a particular IP, it will _always_ be handled at
that IP. If this weren't true, we'd have to track the tuple
(IP,SP,BSP) to uniquely identify the stack frame that's handling
the exception. */
if (unw_get_reg (&context.cursor, UNW_REG_IP, &ip) < 0)
return _URC_FATAL_PHASE1_ERROR;
exception_object->private_1 = 0; /* clear "stop" pointer */
exception_object->private_2 = ip; /* save frame marker */
Debug (1, "found handler for IP=%lx; entering cleanup phase\n", (long) ip);
/* Reset the cursor to the first frame: */
if (unw_init_local (&context.cursor, &uc) < 0)
return _URC_FATAL_PHASE1_ERROR;
return _Unwind_Phase2 (exception_object, &context);
}
/// Walk every frame and call trace function at each one. If trace function
/// returns anything other than _URC_NO_REASON, then walk is terminated.
_LIBUNWIND_EXPORT _Unwind_Reason_Code
_Unwind_Backtrace(_Unwind_Trace_Fn callback, void *ref) {
unw_cursor_t cursor;
unw_context_t uc;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
_LIBUNWIND_TRACE_API("_Unwind_Backtrace(callback=%p)\n", callback);
// walk each frame
while (true) {
_Unwind_Reason_Code result;
// ask libuwind to get next frame (skip over first frame which is
// _Unwind_Backtrace())
if (unw_step(&cursor) <= 0) {
_LIBUNWIND_TRACE_UNWINDING(" _backtrace: ended because cursor reached "
"bottom of stack, returning %d\n",
_URC_END_OF_STACK);
return _URC_END_OF_STACK;
}
#if LIBCXXABI_ARM_EHABI
// Get the information for this frame.
unw_proc_info_t frameInfo;
if (unw_get_proc_info(&cursor, &frameInfo) != UNW_ESUCCESS) {
return _URC_END_OF_STACK;
}
struct _Unwind_Context *context = (struct _Unwind_Context *)&cursor;
const uint32_t* unwindInfo = (uint32_t *) frameInfo.unwind_info;
if ((*unwindInfo & 0x80000000) == 0) {
// 6.2: Generic Model
// EHT entry is a prel31 pointing to the PR, followed by data understood
// only by the personality routine. Since EHABI doesn't guarantee the
// location or availability of the unwind opcodes in the generic model,
// we have to call personality functions with (_US_VIRTUAL_UNWIND_FRAME |
// _US_FORCE_UNWIND) state.
// Create a mock exception object for force unwinding.
_Unwind_Exception ex;
ex.exception_class = 0x434C4E47554E5700; // CLNGUNW\0
ex.pr_cache.fnstart = frameInfo.start_ip;
ex.pr_cache.ehtp = (_Unwind_EHT_Header *) unwindInfo;
ex.pr_cache.additional= frameInfo.flags;
// Get and call the personality function to unwind the frame.
__personality_routine pr = (__personality_routine) readPrel31(unwindInfo);
if (pr(_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND, &ex, context) !=
_URC_CONTINUE_UNWIND) {
return _URC_END_OF_STACK;
}
} else {
size_t off, len;
unwindInfo = decode_eht_entry(unwindInfo, &off, &len);
if (unwindInfo == NULL) {
return _URC_FAILURE;
}
result = _Unwind_VRS_Interpret(context, unwindInfo, off, len);
if (result != _URC_CONTINUE_UNWIND) {
return _URC_END_OF_STACK;
}
}
#endif // LIBCXXABI_ARM_EHABI
// debugging
if (_LIBUNWIND_TRACING_UNWINDING) {
char functionName[512];
unw_proc_info_t frame;
unw_word_t offset;
unw_get_proc_name(&cursor, functionName, 512, &offset);
unw_get_proc_info(&cursor, &frame);
_LIBUNWIND_TRACE_UNWINDING(
" _backtrace: start_ip=0x%llX, func=%s, lsda=0x%llX, context=%p\n",
(long long)frame.start_ip, functionName,
(long long)frame.lsda, &cursor);
}
// call trace function with this frame
result = (*callback)((struct _Unwind_Context *)(&cursor), ref);
if (result != _URC_NO_REASON) {
_LIBUNWIND_TRACE_UNWINDING(" _backtrace: ended because callback "
"returned %d\n",
result);
return result;
}
}
}
// The stack-unwinding loop.
static inline void unwind_loop(ExcInfo* exc_data) {
// NB. https://monoinfinito.wordpress.com/series/exception-handling-in-c/ is a very useful resource
// as are http://www.airs.com/blog/archives/460 and http://www.airs.com/blog/archives/464
unw_cursor_t cursor;
unw_context_t uc; // exists only to initialize cursor
#ifndef NDEBUG
// poison stack memory. have had problems with these structures being insufficiently initialized.
memset(&uc, 0xef, sizeof uc);
memset(&cursor, 0xef, sizeof cursor);
#endif
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
auto unwind_session = getActivePythonUnwindSession();
while (unw_step(&cursor) > 0) {
unw_proc_info_t pip;
static StatCounter frames_unwound("num_frames_unwound_cxx");
frames_unwound.log();
// NB. unw_get_proc_info is slow; a significant chunk of all time spent unwinding is spent here.
check(unw_get_proc_info(&cursor, &pip));
assert((pip.lsda == 0) == (pip.handler == 0));
assert(pip.flags == 0);
if (VERBOSITY("cxx_unwind") >= 4) {
print_frame(&cursor, &pip);
}
// let the PythonUnwindSession know that we're in a new frame,
// giving it a chance to possibly add a traceback entry for
// it.
unwindingThroughFrame(unwind_session, &cursor);
// Skip frames without handlers
if (pip.handler == 0) {
continue;
}
RELEASE_ASSERT(pip.handler == (uintptr_t)__gxx_personality_v0,
"personality function other than __gxx_personality_v0; "
"don't know how to unwind through non-C++ functions");
// Don't call __gxx_personality_v0; we perform dispatch ourselves.
// 1. parse LSDA header
lsda_info_t info;
parse_lsda_header(&pip, &info);
call_site_entry_t entry;
{
// 2. Find our current IP in the call site table.
unw_word_t ip;
unw_get_reg(&cursor, UNW_REG_IP, &ip);
// ip points to the instruction *after* the instruction that caused the error - which is generally (always?)
// a call instruction - UNLESS we're in a signal frame, in which case it points at the instruction that
// caused the error. For now, we assume we're never in a signal frame. So, we decrement it by one.
//
// TODO: double-check that we never hit a signal frame.
--ip;
bool found = find_call_site_entry(&info, (const uint8_t*)ip, &entry);
// If we didn't find an entry, an exception happened somewhere exceptions should never happen; terminate
// immediately.
if (!found) {
panic();
}
}
// 3. Figure out what to do based on the call site entry.
if (!entry.landing_pad) {
// No landing pad means no exception handling or cleanup; keep unwinding!
continue;
}
// After this point we are guaranteed to resume something rather than unwinding further.
if (VERBOSITY("cxx_unwind") >= 4) {
print_lsda(&info);
}
int64_t switch_value = determine_action(&info, &entry);
if (switch_value != CLEANUP_ACTION) {
// we're transfering control to a non-cleanup landing pad.
// i.e. a catch block. thus ends our unwind session.
endPythonUnwindSession(unwind_session);
#if STAT_TIMERS
pyston::StatTimer::finishOverride();
#endif
}
static_assert(THREADING_USE_GIL, "have to make the unwind session usage in this file thread safe!");
// there is a python unwinding implementation detail leaked
// here - that the unwind session can be ended but its
// exception storage is still around.
//
// this manifests itself as this short window here where we've
// (possibly) ended the unwind session above but we still need
// to pass exc_data (which is the exceptionStorage for this
// unwind session) to resume().
//
// the only way this could bite us is if we somehow clobber
// the PythonUnwindSession's storage, or cause a GC to occur, before
// transfering control to the landing pad in resume().
//
resume(&cursor, entry.landing_pad, switch_value, exc_data);
}
// Hit end of stack! return & let unwindException determine what to do.
}
void
do_backtrace(void) {
unw_word_t ip, sp, start_ip = 0, off;
int n = 0, ret;
unw_proc_info_t pi;
unw_cursor_t c;
char buf[512];
size_t len;
ret = unw_init_remote(&c, as, ui);
if (ret < 0)
panic ("unw_init_remote() failed: ret=%d\n", ret);
do {
if ((ret = unw_get_reg(&c, UNW_REG_IP, &ip)) < 0
|| (ret = unw_get_reg(&c, UNW_REG_SP, &sp)) < 0)
panic ("unw_get_reg/unw_get_proc_name() failed: ret=%d\n", ret);
if (n == 0)
start_ip = ip;
buf[0] = '\0';
if (print_names)
unw_get_proc_name(&c, buf, sizeof(buf), &off);
if (verbose) {
if (off) {
len = strlen(buf);
if (len >= sizeof(buf) - 32)
len = sizeof(buf) - 32;
sprintf(buf + len, "+0x%lx", (unsigned long) off);
}
printf("%016lx %-32s (sp=%016lx)\n", (long) ip, buf, (long) sp);
}
if ((ret = unw_get_proc_info(&c, &pi)) < 0)
panic ("unw_get_proc_info(ip=0x%lx) failed: ret=%d\n", (long) ip, ret);
else if (verbose)
printf("\tproc=%016lx-%016lx\n\thandler=%lx lsda=%lx",
(long) pi.start_ip, (long) pi.end_ip,
(long) pi.handler, (long) pi.lsda);
if (verbose)
printf("\n");
ret = unw_step(&c);
if (ret < 0) {
unw_get_reg(&c, UNW_REG_IP, &ip);
panic ("FAILURE: unw_step() returned %d for ip=%lx (start ip=%lx)\n",
ret, (long) ip, (long) start_ip);
}
if (++n > 64) {
/* guard against bad unwind info in old libraries... */
panic ("too deeply nested---assuming bogus unwind (start ip=%lx)\n",
(long) start_ip);
break;
}
if (nerrors > nerrors_max) {
panic ("Too many errors (%d)!\n", nerrors);
break;
}
}
while (ret > 0);
if (ret < 0)
panic ("unwind failed with ret=%d\n", ret);
if (verbose)
printf("================\n\n");
}
static _Unwind_Reason_Code
unwind_phase2(unw_context_t *uc, _Unwind_Exception *exception_object) {
unw_cursor_t cursor2;
unw_init_local(&cursor2, uc);
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)\n", exception_object);
// Walk each frame until we reach where search phase said to stop.
while (true) {
// Ask libuwind to get next frame (skip over first which is
// _Unwind_RaiseException).
int stepResult = unw_step(&cursor2);
if (stepResult == 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step() reached "
"bottom => _URC_END_OF_STACK\n",
exception_object);
return _URC_END_OF_STACK;
} else if (stepResult < 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step failed => "
"_URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// Get info about this frame.
unw_word_t sp;
unw_proc_info_t frameInfo;
unw_get_reg(&cursor2, UNW_REG_SP, &sp);
if (unw_get_proc_info(&cursor2, &frameInfo) != UNW_ESUCCESS) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_get_proc_info "
"failed => _URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// When tracing, print state information.
if (_LIBUNWIND_TRACING_UNWINDING) {
char functionName[512];
unw_word_t offset;
if ((unw_get_proc_name(&cursor2, functionName, 512, &offset) !=
UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip))
strcpy(functionName, ".anonymous.");
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2(ex_ojb=%p): start_ip=0x%llX, func=%s, sp=0x%llX, "
"lsda=0x%llX, personality=0x%llX\n",
exception_object, frameInfo.start_ip, functionName, sp,
frameInfo.lsda, frameInfo.handler);
}
// If there is a personality routine, tell it we are unwinding.
if (frameInfo.handler != 0) {
__personality_routine p =
(__personality_routine)(long)(frameInfo.handler);
_Unwind_Action action = _UA_CLEANUP_PHASE;
if (sp == exception_object->private_2) {
// Tell personality this was the frame it marked in phase 1.
action = (_Unwind_Action)(_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME);
}
_Unwind_Reason_Code personalityResult =
(*p)(1, action, exception_object->exception_class, exception_object,
(struct _Unwind_Context *)(&cursor2));
switch (personalityResult) {
case _URC_CONTINUE_UNWIND:
// Continue unwinding
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND\n",
exception_object);
if (sp == exception_object->private_2) {
// Phase 1 said we would stop at this frame, but we did not...
_LIBUNWIND_ABORT("during phase1 personality function said it would "
"stop here, but now in phase2 it did not stop here");
}
break;
case _URC_INSTALL_CONTEXT:
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT\n",
exception_object);
// Personality routine says to transfer control to landing pad.
// We may get control back if landing pad calls _Unwind_Resume().
if (_LIBUNWIND_TRACING_UNWINDING) {
unw_word_t pc;
unw_get_reg(&cursor2, UNW_REG_IP, &pc);
unw_get_reg(&cursor2, UNW_REG_SP, &sp);
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering "
"user code with ip=0x%llX, sp=0x%llX\n",
exception_object, pc, sp);
}
unw_resume(&cursor2);
// unw_resume() only returns if there was an error.
return _URC_FATAL_PHASE2_ERROR;
default:
// Personality routine returned an unknown result code.
_LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d",
personalityResult);
return _URC_FATAL_PHASE2_ERROR;
}
}
}
// Clean up phase did not resume at the frame that the search phase
// said it would...
return _URC_FATAL_PHASE2_ERROR;
}
static _Unwind_Reason_Code
unwind_phase2_forced(unw_context_t *uc,
_Unwind_Exception *exception_object,
_Unwind_Stop_Fn stop, void *stop_parameter) {
unw_cursor_t cursor2;
unw_init_local(&cursor2, uc);
// Walk each frame until we reach where search phase said to stop
while (unw_step(&cursor2) > 0) {
// Update info about this frame.
unw_proc_info_t frameInfo;
if (unw_get_proc_info(&cursor2, &frameInfo) != UNW_ESUCCESS) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): unw_step "
"failed => _URC_END_OF_STACK\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// When tracing, print state information.
if (_LIBUNWIND_TRACING_UNWINDING) {
char functionName[512];
unw_word_t offset;
if ((unw_get_proc_name(&cursor2, functionName, 512, &offset) !=
UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip))
strcpy(functionName, ".anonymous.");
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"start_ip=0x%llX, func=%s, lsda=0x%llX, "
" personality=0x%llX\n",
exception_object, frameInfo.start_ip,
functionName, frameInfo.lsda,
frameInfo.handler);
}
// Call stop function at each frame.
_Unwind_Action action =
(_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE);
_Unwind_Reason_Code stopResult =
(*stop)(1, action, exception_object->exception_class, exception_object,
(struct _Unwind_Context *)(&cursor2), stop_parameter);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2_forced(ex_ojb=%p): stop function returned %d\n",
exception_object, stopResult);
if (stopResult != _URC_NO_REASON) {
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2_forced(ex_ojb=%p): stopped by stop function\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// If there is a personality routine, tell it we are unwinding.
if (frameInfo.handler != 0) {
__personality_routine p =
(__personality_routine)(long)(frameInfo.handler);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2_forced(ex_ojb=%p): calling personality function %p\n",
exception_object, p);
_Unwind_Reason_Code personalityResult =
(*p)(1, action, exception_object->exception_class, exception_object,
(struct _Unwind_Context *)(&cursor2));
switch (personalityResult) {
case _URC_CONTINUE_UNWIND:
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"personality returned _URC_CONTINUE_UNWIND\n",
exception_object);
// Destructors called, continue unwinding
break;
case _URC_INSTALL_CONTEXT:
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"personality returned _URC_INSTALL_CONTEXT\n",
exception_object);
// We may get control back if landing pad calls _Unwind_Resume().
unw_resume(&cursor2);
break;
default:
// Personality routine returned an unknown result code.
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"personality returned %d, "
"_URC_FATAL_PHASE2_ERROR\n",
exception_object, personalityResult);
return _URC_FATAL_PHASE2_ERROR;
}
}
}
// Call stop function one last time and tell it we've reached the end
// of the stack.
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): calling stop "
"function with _UA_END_OF_STACK\n",
exception_object);
_Unwind_Action lastAction =
(_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE | _UA_END_OF_STACK);
(*stop)(1, lastAction, exception_object->exception_class, exception_object,
(struct _Unwind_Context *)(&cursor2), stop_parameter);
// Clean up phase did not resume at the frame that the search phase said it
// would.
return _URC_FATAL_PHASE2_ERROR;
}
static _Unwind_Reason_Code
unwind_phase1(unw_context_t *uc, struct _Unwind_Exception *exception_object) {
// EHABI #7.3 discusses preserving the VRS in a "temporary VRS" during
// phase 1 and then restoring it to the "primary VRS" for phase 2. The
// effect is phase 2 doesn't see any of the VRS manipulations from phase 1.
// In this implementation, the phases don't share the VRS backing store.
// Instead, they are passed the original |uc| and they create a new VRS
// from scratch thus achieving the same effect.
unw_cursor_t cursor1;
unw_init_local(&cursor1, uc);
// Walk each frame looking for a place to stop.
for (bool handlerNotFound = true; handlerNotFound;) {
// Ask libuwind to get next frame (skip over first which is
// _Unwind_RaiseException).
int stepResult = unw_step(&cursor1);
if (stepResult == 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step() reached "
"bottom => _URC_END_OF_STACK\n",
exception_object);
return _URC_END_OF_STACK;
} else if (stepResult < 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step failed => "
"_URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE1_ERROR;
}
// See if frame has code to run (has personality routine).
unw_proc_info_t frameInfo;
unw_word_t sp;
if (unw_get_proc_info(&cursor1, &frameInfo) != UNW_ESUCCESS) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_get_proc_info "
"failed => _URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE1_ERROR;
}
// When tracing, print state information.
if (_LIBUNWIND_TRACING_UNWINDING) {
char functionName[512];
unw_word_t offset;
if ((unw_get_proc_name(&cursor1, functionName, 512, &offset) !=
UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip))
strcpy(functionName, ".anonymous.");
unw_word_t pc;
unw_get_reg(&cursor1, UNW_REG_IP, &pc);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): pc=0x%llX, start_ip=0x%lX, func=%s, "
"lsda=0x%llX, personality=0x%llX\n",
exception_object, pc, frameInfo.start_ip, functionName,
frameInfo.lsda, frameInfo.handler);
}
// If there is a personality routine, ask it if it will want to stop at
// this frame.
if (frameInfo.handler != 0) {
__personality_routine p =
(__personality_routine)(long)(frameInfo.handler);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): calling personality function %p\n",
exception_object, p);
struct _Unwind_Context *context = (struct _Unwind_Context *)(&cursor1);
#ifdef __arm__
exception_object->pr_cache.fnstart = frameInfo.start_ip;
exception_object->pr_cache.ehtp = (_Unwind_EHT_Header *)frameInfo.unwind_info;
exception_object->pr_cache.additional = frameInfo.flags;
_Unwind_Reason_Code personalityResult =
(*p)(_US_VIRTUAL_UNWIND_FRAME, exception_object, context);
#else
_Unwind_Reason_Code personalityResult =
(*p)(1, _UA_SEARCH_PHASE, exception_object->exception_class,
exception_object, context);
#endif
switch (personalityResult) {
case _URC_HANDLER_FOUND:
// found a catch clause or locals that need destructing in this frame
// stop search and remember stack pointer at the frame
handlerNotFound = false;
#ifndef __arm__
unw_get_reg(&cursor1, UNW_REG_SP, &sp);
exception_object->private_2 = (uintptr_t)sp;
#else
// p should have initialized barrier_cache. #7.3.5
#endif
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): "
"_URC_HANDLER_FOUND \n",
exception_object);
return _URC_NO_REASON;
case _URC_CONTINUE_UNWIND:
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND\n",
exception_object);
// continue unwinding
break;
#ifdef __arm__
// # 7.3.3
case _URC_FAILURE:
return _URC_FAILURE;
#endif
default:
// something went wrong
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE1_ERROR;
}
}
}
return _URC_NO_REASON;
}
static _Unwind_Reason_Code
unwind_phase2(unw_context_t *uc, struct _Unwind_Exception *exception_object, bool resume) {
// See comment at the start of unwind_phase1 regarding VRS integrity.
unw_cursor_t cursor2;
unw_init_local(&cursor2, uc);
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p)\n", exception_object);
int frame_count = 0;
// Walk each frame until we reach where search phase said to stop.
while (true) {
// Ask libuwind to get next frame (skip over first which is
// _Unwind_RaiseException or _Unwind_Resume).
//
// Resume only ever makes sense for 1 frame.
_Unwind_State state =
resume ? _US_UNWIND_FRAME_RESUME : _US_UNWIND_FRAME_STARTING;
if (resume && frame_count == 1) {
// On a resume, first unwind the _Unwind_Resume() frame. The next frame
// is now the landing pad for the cleanup from a previous execution of
// phase2. To continue unwindingly correctly, replace VRS[15] with the
// IP of the frame that the previous run of phase2 installed the context
// for. After this, continue unwinding as if normal.
//
// See #7.4.6 for details.
unw_set_reg(&cursor2, UNW_REG_IP, exception_object->unwinder_cache.reserved2);
resume = false;
}
int stepResult = unw_step(&cursor2);
if (stepResult == 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step() reached "
"bottom => _URC_END_OF_STACK\n",
exception_object);
return _URC_END_OF_STACK;
} else if (stepResult < 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_step failed => "
"_URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// Get info about this frame.
unw_word_t sp;
unw_proc_info_t frameInfo;
unw_get_reg(&cursor2, UNW_REG_SP, &sp);
if (unw_get_proc_info(&cursor2, &frameInfo) != UNW_ESUCCESS) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): unw_get_proc_info "
"failed => _URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// When tracing, print state information.
if (_LIBUNWIND_TRACING_UNWINDING) {
char functionName[512];
unw_word_t offset;
if ((unw_get_proc_name(&cursor2, functionName, 512, &offset) !=
UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip))
strcpy(functionName, ".anonymous.");
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2(ex_ojb=%p): start_ip=0x%llX, func=%s, sp=0x%llX, "
"lsda=0x%llX, personality=0x%llX\n",
exception_object, frameInfo.start_ip, functionName, sp,
frameInfo.lsda, frameInfo.handler);
}
// If there is a personality routine, tell it we are unwinding.
if (frameInfo.handler != 0) {
__personality_routine p =
(__personality_routine)(long)(frameInfo.handler);
struct _Unwind_Context *context = (struct _Unwind_Context *)(&cursor2);
#ifdef __arm__
exception_object->pr_cache.fnstart = frameInfo.start_ip;
exception_object->pr_cache.ehtp = (_Unwind_EHT_Header *)frameInfo.unwind_info;
exception_object->pr_cache.additional = frameInfo.flags;
_Unwind_Reason_Code personalityResult =
(*p)(state, exception_object, context);
#else
_Unwind_Action action = _UA_CLEANUP_PHASE;
if (sp == exception_object->private_2) {
// Tell personality this was the frame it marked in phase 1.
action = (_Unwind_Action)(_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME);
}
_Unwind_Reason_Code personalityResult =
(*p)(1, action, exception_object->exception_class, exception_object,
context);
#endif
switch (personalityResult) {
case _URC_CONTINUE_UNWIND:
// Continue unwinding
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2(ex_ojb=%p): _URC_CONTINUE_UNWIND\n",
exception_object);
#ifdef __arm__
if (sp == exception_object->barrier_cache.sp) {
#else
if (sp == exception_object->private_2) {
#endif
// Phase 1 said we would stop at this frame, but we did not...
_LIBUNWIND_ABORT("during phase1 personality function said it would "
"stop here, but now in phase2 it did not stop here");
}
break;
case _URC_INSTALL_CONTEXT:
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2(ex_ojb=%p): _URC_INSTALL_CONTEXT\n",
exception_object);
// Personality routine says to transfer control to landing pad.
// We may get control back if landing pad calls _Unwind_Resume().
if (_LIBUNWIND_TRACING_UNWINDING) {
unw_word_t pc;
unw_get_reg(&cursor2, UNW_REG_IP, &pc);
unw_get_reg(&cursor2, UNW_REG_SP, &sp);
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2(ex_ojb=%p): re-entering "
"user code with ip=0x%llX, sp=0x%llX\n",
exception_object, pc, sp);
}
#ifdef __arm__
// #7.4.1 says we need to preserve pc for when _Unwind_Resume is called
// back, to find this same frame.
unw_word_t pc;
unw_get_reg(&cursor2, UNW_REG_IP, &pc);
exception_object->unwinder_cache.reserved2 = (uint32_t)pc;
#endif
unw_resume(&cursor2);
// unw_resume() only returns if there was an error.
return _URC_FATAL_PHASE2_ERROR;
#ifdef __arm__
// # 7.4.3
case _URC_FAILURE:
abort();
#endif
default:
// Personality routine returned an unknown result code.
_LIBUNWIND_DEBUG_LOG("personality function returned unknown result %d",
personalityResult);
return _URC_FATAL_PHASE2_ERROR;
}
}
frame_count++;
}
// Clean up phase did not resume at the frame that the search phase
// said it would...
return _URC_FATAL_PHASE2_ERROR;
}
#ifndef __arm__
static _Unwind_Reason_Code
unwind_phase2_forced(unw_context_t *uc,
struct _Unwind_Exception *exception_object,
_Unwind_Stop_Fn stop, void *stop_parameter) {
unw_cursor_t cursor2;
unw_init_local(&cursor2, uc);
// Walk each frame until we reach where search phase said to stop
while (unw_step(&cursor2) > 0) {
// Update info about this frame.
unw_proc_info_t frameInfo;
if (unw_get_proc_info(&cursor2, &frameInfo) != UNW_ESUCCESS) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): unw_step "
"failed => _URC_END_OF_STACK\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// When tracing, print state information.
if (_LIBUNWIND_TRACING_UNWINDING) {
char functionName[512];
unw_word_t offset;
if ((unw_get_proc_name(&cursor2, functionName, 512, &offset) !=
UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip))
strcpy(functionName, ".anonymous.");
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"start_ip=0x%llX, func=%s, lsda=0x%llX, "
" personality=0x%llX\n",
exception_object, frameInfo.start_ip,
functionName, frameInfo.lsda,
frameInfo.handler);
}
// Call stop function at each frame.
_Unwind_Action action =
(_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE);
_Unwind_Reason_Code stopResult =
(*stop)(1, action, exception_object->exception_class, exception_object,
(struct _Unwind_Context *)(&cursor2), stop_parameter);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2_forced(ex_ojb=%p): stop function returned %d\n",
exception_object, stopResult);
if (stopResult != _URC_NO_REASON) {
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2_forced(ex_ojb=%p): stopped by stop function\n",
exception_object);
return _URC_FATAL_PHASE2_ERROR;
}
// If there is a personality routine, tell it we are unwinding.
if (frameInfo.handler != 0) {
__personality_routine p =
(__personality_routine)(long)(frameInfo.handler);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase2_forced(ex_ojb=%p): calling personality function %p\n",
exception_object, p);
_Unwind_Reason_Code personalityResult =
(*p)(1, action, exception_object->exception_class, exception_object,
(struct _Unwind_Context *)(&cursor2));
switch (personalityResult) {
case _URC_CONTINUE_UNWIND:
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"personality returned _URC_CONTINUE_UNWIND\n",
exception_object);
// Destructors called, continue unwinding
break;
case _URC_INSTALL_CONTEXT:
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"personality returned _URC_INSTALL_CONTEXT\n",
exception_object);
// We may get control back if landing pad calls _Unwind_Resume().
unw_resume(&cursor2);
break;
default:
// Personality routine returned an unknown result code.
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): "
"personality returned %d, "
"_URC_FATAL_PHASE2_ERROR\n",
exception_object, personalityResult);
return _URC_FATAL_PHASE2_ERROR;
}
}
}
// Call stop function one last time and tell it we've reached the end
// of the stack.
_LIBUNWIND_TRACE_UNWINDING("unwind_phase2_forced(ex_ojb=%p): calling stop "
"function with _UA_END_OF_STACK\n",
exception_object);
_Unwind_Action lastAction =
(_Unwind_Action)(_UA_FORCE_UNWIND | _UA_CLEANUP_PHASE | _UA_END_OF_STACK);
(*stop)(1, lastAction, exception_object->exception_class, exception_object,
(struct _Unwind_Context *)(&cursor2), stop_parameter);
// Clean up phase did not resume at the frame that the search phase said it
// would.
return _URC_FATAL_PHASE2_ERROR;
}
static void chpl_stack_unwind(void){
// This is just a prototype using libunwind
unw_cursor_t cursor;
unw_context_t uc;
unw_word_t wordValue;
char buffer[128];
unsigned int line;
#ifdef __linux__
unw_proc_info_t info;
// Get the exec path and name for the precise line printing
char process_name[128];
line = readlink("/proc/self/exe", process_name, sizeof(process_name));
// It unlikely to happen but this means that the process name is too big
// for our buffer. In this case, we truncate the name
if(line == sizeof(process_name))
line = sizeof(process_name)-1;
process_name[line] = '\0';
#endif
// Check if we need to print the stack trace (default = yes)
if(! chpl_get_rt_env_bool("UNWIND", true)) {
return;
}
line = 0;
unw_getcontext(&uc);
unw_init_local(&cursor, &uc);
if(chpl_sizeSymTable > 0)
fprintf(stderr,"Stacktrace\n\n");
// This loop does the effective stack unwind, see libunwind documentation
while (unw_step(&cursor) > 0) {
unw_get_proc_name(&cursor, buffer, sizeof(buffer), &wordValue);
// Since this stack trace is printed out a program exit, we do not believe
// it is performance sensitive. Additionally, this initial implementation
// favors simplicity over performance.
//
// If it becomes necessary to improve performance, this code could use be
// faster using one of these two strategies:
// 1) Use a hashtable or map to find entries in chpl_funSymTable, or
// 2) Emit chpl_funSymTable in sorted order and use binary search on it
for(int t = 0; t < chpl_sizeSymTable; t+=2 ){
if (!strcmp(chpl_funSymTable[t], buffer)){
#ifdef __linux__
// Maybe we can get a more precise line number
unw_get_proc_info(&cursor, &info);
line = chpl_unwind_getLineNum(process_name,
(void *)(info.start_ip + wordValue));
// We wasn't able to obtain the line number, let's use the procedure
// line number
if(line == 0)
line = chpl_filenumSymTable[t+1];
#else
line = chpl_filenumSymTable[t+1];
#endif
fprintf(stderr,"%s() at %s:%d\n",
chpl_funSymTable[t+1],
chpl_lookupFilename(chpl_filenumSymTable[t]),
line);
break;
}
}
}
}
/* Benefit from maps being sorted by address */
if (addr < mapsList[i].start) {
break;
}
}
return NULL;
}
#ifndef __ANDROID__
size_t arch_unwindStack(pid_t pid, funcs_t * funcs)
{
size_t num_frames = 0, mapsCnt = 0;
procMap_t *mapsList = arch_parsePidMaps(pid, &mapsCnt);
defer {
free(mapsList);
};
unw_addr_space_t as = unw_create_addr_space(&_UPT_accessors, __BYTE_ORDER);
if (!as) {
LOG_E("[pid='%d'] unw_create_addr_space failed", pid);
return num_frames;
}
defer {
unw_destroy_addr_space(as);
};
void *ui = _UPT_create(pid);
if (ui == NULL) {
LOG_E("[pid='%d'] _UPT_create failed", pid);
return num_frames;
}
defer {
_UPT_destroy(ui);
};
unw_cursor_t c;
int ret = unw_init_remote(&c, as, ui);
if (ret < 0) {
LOG_E("[pid='%d'] unw_init_remote failed (%s)", pid, UNW_ER[-ret]);
return num_frames;
}
for (num_frames = 0; unw_step(&c) > 0 && num_frames < _HF_MAX_FUNCS; num_frames++) {
unw_word_t ip;
char *mapName = NULL;
ret = unw_get_reg(&c, UNW_REG_IP, &ip);
if (ret < 0) {
LOG_E("[pid='%d'] [%zd] failed to read IP (%s)", pid, num_frames, UNW_ER[-ret]);
funcs[num_frames].pc = 0;
} else {
funcs[num_frames].pc = (void *)ip;
}
if (mapsCnt > 0 && (mapName = arch_searchMaps(ip, mapsCnt, mapsList)) != NULL) {
memcpy(funcs[num_frames].mapName, mapName, sizeof(funcs[num_frames].mapName));
} else {
strncpy(funcs[num_frames].mapName, "UNKNOWN", sizeof(funcs[num_frames].mapName));
}
}
return num_frames;
}
#else /* !defined(__ANDROID__) */
size_t arch_unwindStack(pid_t pid, funcs_t * funcs)
{
size_t num_frames = 0, mapsCnt = 0;
procMap_t *mapsList = arch_parsePidMaps(pid, &mapsCnt);
defer {
free(mapsList);
}
unw_addr_space_t as = unw_create_addr_space(&_UPT_accessors, __BYTE_ORDER);
if (!as) {
LOG_E("[pid='%d'] unw_create_addr_space failed", pid);
return num_frames;
}
defer {
unw_destroy_addr_space(as);
};
struct UPT_info *ui = (struct UPT_info *)_UPT_create(pid);
if (ui == NULL) {
LOG_E("[pid='%d'] _UPT_create failed", pid);
return num_frames;
}
defer {
_UPT_destroy(ui);
};
unw_cursor_t cursor;
int ret = unw_init_remote(&cursor, as, ui);
if (ret < 0) {
LOG_E("[pid='%d'] unw_init_remote failed (%s)", pid, UNW_ER[-ret]);
return num_frames;
}
do {
char *mapName = NULL;
unw_word_t pc = 0, offset = 0;
char buf[_HF_FUNC_NAME_SZ] = { 0 };
ret = unw_get_reg(&cursor, UNW_REG_IP, &pc);
if (ret < 0) {
LOG_E("[pid='%d'] [%zd] failed to read IP (%s)", pid, num_frames, UNW_ER[-ret]);
// We don't want to try to extract info from an arbitrary IP
// TODO: Maybe abort completely (goto out))
goto skip_frame_info;
}
unw_proc_info_t frameInfo;
ret = unw_get_proc_info(&cursor, &frameInfo);
if (ret < 0) {
LOG_D("[pid='%d'] [%zd] unw_get_proc_info (%s)", pid, num_frames, UNW_ER[-ret]);
// Not safe to keep parsing frameInfo
goto skip_frame_info;
}
ret = unw_get_proc_name(&cursor, buf, sizeof(buf), &offset);
if (ret < 0) {
LOG_D("[pid='%d'] [%zd] unw_get_proc_name() failed (%s)", pid, num_frames,
UNW_ER[-ret]);
buf[0] = '\0';
}
skip_frame_info:
// Compared to bfd, line var plays the role of offset from func_name
// Reports format is adjusted accordingly to reflect in saved file
funcs[num_frames].line = offset;
funcs[num_frames].pc = (void *)pc;
memcpy(funcs[num_frames].func, buf, sizeof(funcs[num_frames].func));
if (mapsCnt > 0 && (mapName = arch_searchMaps(pc, mapsCnt, mapsList)) != NULL) {
memcpy(funcs[num_frames].mapName, mapName, sizeof(funcs[num_frames].mapName));
} else {
strncpy(funcs[num_frames].mapName, "UNKNOWN", sizeof(funcs[num_frames].mapName));
}
num_frames++;
ret = unw_step(&cursor);
} while (ret > 0 && num_frames < _HF_MAX_FUNCS);
return num_frames;
}
static _Unwind_Reason_Code
unwind_phase1(unw_context_t *uc, _Unwind_Exception *exception_object) {
unw_cursor_t cursor1;
unw_init_local(&cursor1, uc);
// Walk each frame looking for a place to stop.
for (bool handlerNotFound = true; handlerNotFound;) {
// Ask libuwind to get next frame (skip over first which is
// _Unwind_RaiseException).
int stepResult = unw_step(&cursor1);
if (stepResult == 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step() reached "
"bottom => _URC_END_OF_STACK\n",
exception_object);
return _URC_END_OF_STACK;
} else if (stepResult < 0) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_step failed => "
"_URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE1_ERROR;
}
// See if frame has code to run (has personality routine).
unw_proc_info_t frameInfo;
unw_word_t sp;
if (unw_get_proc_info(&cursor1, &frameInfo) != UNW_ESUCCESS) {
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): unw_get_proc_info "
"failed => _URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE1_ERROR;
}
// When tracing, print state information.
if (_LIBUNWIND_TRACING_UNWINDING) {
char functionName[512];
unw_word_t offset;
if ((unw_get_proc_name(&cursor1, functionName, 512, &offset) !=
UNW_ESUCCESS) || (frameInfo.start_ip + offset > frameInfo.end_ip))
strcpy(functionName, ".anonymous.");
unw_word_t pc;
unw_get_reg(&cursor1, UNW_REG_IP, &pc);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): pc=0x%llX, start_ip=0x%llX, func=%s, "
"lsda=0x%llX, personality=0x%llX\n",
exception_object, pc, frameInfo.start_ip, functionName,
frameInfo.lsda, frameInfo.handler);
}
// If there is a personality routine, ask it if it will want to stop at
// this frame.
if (frameInfo.handler != 0) {
__personality_routine p =
(__personality_routine)(long)(frameInfo.handler);
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): calling personality function %p\n",
exception_object, p);
_Unwind_Reason_Code personalityResult =
(*p)(1, _UA_SEARCH_PHASE, exception_object->exception_class,
exception_object, (struct _Unwind_Context *)(&cursor1));
switch (personalityResult) {
case _URC_HANDLER_FOUND:
// found a catch clause or locals that need destructing in this frame
// stop search and remember stack pointer at the frame
handlerNotFound = false;
unw_get_reg(&cursor1, UNW_REG_SP, &sp);
exception_object->private_2 = (uintptr_t)sp;
_LIBUNWIND_TRACE_UNWINDING("unwind_phase1(ex_ojb=%p): "
"_URC_HANDLER_FOUND \n",
exception_object);
return _URC_NO_REASON;
case _URC_CONTINUE_UNWIND:
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): _URC_CONTINUE_UNWIND\n",
exception_object);
// continue unwinding
break;
default:
// something went wrong
_LIBUNWIND_TRACE_UNWINDING(
"unwind_phase1(ex_ojb=%p): _URC_FATAL_PHASE1_ERROR\n",
exception_object);
return _URC_FATAL_PHASE1_ERROR;
}
}
}
return _URC_NO_REASON;
}
