static int frame_callback(Dwfl_Frame *frame, void *userdata) {
struct stack_context *c = userdata;
Dwarf_Addr pc, pc_adjusted, bias = 0;
_cleanup_free_ Dwarf_Die *scopes = NULL;
const char *fname = NULL, *symbol = NULL;
Dwfl_Module *module;
bool is_activation;
assert(frame);
assert(c);
if (c->n_frame >= FRAMES_MAX)
return DWARF_CB_ABORT;
if (!dwfl_frame_pc(frame, &pc, &is_activation))
return DWARF_CB_ABORT;
pc_adjusted = pc - (is_activation ? 0 : 1);
module = dwfl_addrmodule(c->dwfl, pc_adjusted);
if (module) {
Dwarf_Die *s, *cudie;
int n;
cudie = dwfl_module_addrdie(module, pc_adjusted, &bias);
if (cudie) {
n = dwarf_getscopes(cudie, pc_adjusted - bias, &scopes);
for (s = scopes; s < scopes + n; s++) {
if (IN_SET(dwarf_tag(s), DW_TAG_subprogram, DW_TAG_inlined_subroutine, DW_TAG_entry_point)) {
Dwarf_Attribute *a, space;
a = dwarf_attr_integrate(s, DW_AT_MIPS_linkage_name, &space);
if (!a)
a = dwarf_attr_integrate(s, DW_AT_linkage_name, &space);
if (a)
symbol = dwarf_formstring(a);
if (!symbol)
symbol = dwarf_diename(s);
if (symbol)
break;
}
}
}
if (!symbol)
symbol = dwfl_module_addrname(module, pc_adjusted);
fname = dwfl_module_info(module, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
}
fprintf(c->f, "#%-2u 0x%016" PRIx64 " %s (%s)\n", c->n_frame, (uint64_t) pc, strna(symbol), strna(fname));
c->n_frame ++;
return DWARF_CB_OK;
}
static struct frame* unwind_thread(Dwfl *dwfl, unw_addr_space_t as,
struct UCD_info *ui, int thread_no,
struct expr_context *ctx)
{
info("thread %d:", thread_no);
int i, ret;
unw_cursor_t c, c_cfa;
_UCD_select_thread(ui, thread_no);
ret = unw_init_remote(&c, as, ui);
fail_if(ret < 0, "unw_init_remote");
ret = unw_init_remote(&c_cfa, as, ui);
fail_if(ret < 0, "unw_init_remote");
struct frame *head = NULL, *tail = NULL;
/* infinite loop insurance */
int count = 1000;
while (--count > 0)
{
unw_word_t ip;
ret = unw_get_reg(&c, UNW_REG_IP, &ip);
fail_if(ret < 0, "unw_get_reg");
if (ip == 0)
break;
unw_word_t off;
char funcname[10*1024];
funcname[0] = '\0';
ret = unw_get_proc_name(&c, funcname, sizeof(funcname)-1, &off);
if (ret < 0)
{
warn("unw_get_proc_name failed for IP %lx", (unsigned long)ip);
}
info("\t%llx %s", (unsigned long long)ip, funcname);
/* According to spec[1], CFA is RSP of the previous frame. However,
* libunwind returns CFA = RSP of the current frame. So we need to keep
* track of the previous (i.e. next to be unwound) frame.
*
* [1] System V Application Binary Interface AMD64 Architecture
* Processor Supplement
* http://www.x86-64.org/documentation/abi.pdf
*/
ctx->cfa = 0;
ret = unw_step(&c_cfa);
if (ret > 0)
{
unw_word_t cfa;
ret = unw_get_reg(&c_cfa, UNW_X86_64_CFA, &cfa);
if (ret == 0)
{
ctx->cfa = (Dwarf_Addr)cfa;
}
}
/* find compilation unit owning the IP */
Dwarf_Die *cu = dwfl_addrdie(dwfl, (Dwarf_Addr)ip, &(ctx->bias));
if (!cu)
{
warn("\t\tcannot find CU for ip %lx", (unsigned long)ip);
goto synth_frame;
}
if (!supported_language(cu))
{
warn("\t\tunsupported CU language");
goto synth_frame;
}
/* needed by child_variables */
Dwarf_Files *files;
ret = dwarf_getsrcfiles(cu, &files, NULL);
fail_if(ret == -1, "dwarf_getsrcfiles");
/* dwarf expression evaluation needs register values */
ctx->curs = &c;
ctx->ip = (Dwarf_Addr)ip; /* TODO: subtract 1 as this is return address? */
/* TODO: we have CU - fall back to CU name if subprogram not found */
/* Following code deals with inlined functions, which do not have their
* own stack frame. It is somewhat ugly due to two constraints:
* - we want to produce at least one frame even if analyze_scopes
* fails
* - we may want to further process the frame that is returned the
* last, i.e. the one that belongs to the non-inlined function
*/
Dwarf_Die *scopes;
int nscopes = dwarf_getscopes(cu, (Dwarf_Addr)ip, &scopes);
struct frame *frame = analyze_scopes(&scopes, &nscopes, ctx, files, false);
if (frame == NULL)
{
goto synth_frame;
}
struct frame *last_frame;
while (frame)
{
list_append(head, tail, frame);
last_frame = frame;
frame = analyze_scopes(&scopes, &nscopes, ctx, files, true);
}
frame = last_frame;
/* frame->ip = (uint64_t)ip; */
goto next;
synth_frame:
/* synthesize frame even though we have no other information except
* that it's there */
frame = xalloc(sizeof(*frame));
list_append(head, tail, frame);
/* frame->ip = (uint64_t)ip; */
next:
ret = unw_step(&c);
fail_if(ret < 0, "unw_step");
if (ret == 0)
break;
}
return head;
}
