diff options
Diffstat (limited to 'gdb/dwarf2loc.c')
| -rw-r--r-- | gdb/dwarf2loc.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c index 980e9ab..1661d9f 100644 --- a/gdb/dwarf2loc.c +++ b/gdb/dwarf2loc.c @@ -399,6 +399,321 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch, } } +/* Convert function entry point exact address ADDR to the function which is + compliant with TAIL_CALL_LIST_COMPLETE condition. Throw + NO_ENTRY_VALUE_ERROR otherwise. */ + +static struct symbol * +func_addr_to_tail_call_list (struct gdbarch *gdbarch, CORE_ADDR addr) +{ + struct symbol *sym = find_pc_function (addr); + struct type *type; + + if (sym == NULL || BLOCK_START (SYMBOL_BLOCK_VALUE (sym)) != addr) + throw_error (NO_ENTRY_VALUE_ERROR, + _("DW_TAG_GNU_call_site resolving failed to find function " + "name for address %s"), + paddress (gdbarch, addr)); + + type = SYMBOL_TYPE (sym); + gdb_assert (TYPE_CODE (type) == TYPE_CODE_FUNC); + gdb_assert (TYPE_SPECIFIC_FIELD (type) == TYPE_SPECIFIC_FUNC); + + return sym; +} + +/* Print user readable form of CALL_SITE->PC to gdb_stdlog. Used only for + ENTRY_VALUES_DEBUG. */ + +static void +tailcall_dump (struct gdbarch *gdbarch, const struct call_site *call_site) +{ + CORE_ADDR addr = call_site->pc; + struct minimal_symbol *msym = lookup_minimal_symbol_by_pc (addr - 1); + + fprintf_unfiltered (gdb_stdlog, " %s(%s)", paddress (gdbarch, addr), + msym == NULL ? "???" : SYMBOL_PRINT_NAME (msym)); + +} + +/* vec.h needs single word type name, typedef it. */ +typedef struct call_site *call_sitep; + +/* Define VEC (call_sitep) functions. */ +DEF_VEC_P (call_sitep); + +/* Intersect RESULTP with CHAIN to keep RESULTP unambiguous, keep in RESULTP + only top callers and bottom callees which are present in both. GDBARCH is + used only for ENTRY_VALUES_DEBUG. RESULTP is NULL after return if there are + no remaining possibilities to provide unambiguous non-trivial result. + RESULTP should point to NULL on the first (initialization) call. Caller is + responsible for xfree of any RESULTP data. */ + +static void +chain_candidate (struct gdbarch *gdbarch, struct call_site_chain **resultp, + VEC (call_sitep) *chain) +{ + struct call_site_chain *result = *resultp; + long length = VEC_length (call_sitep, chain); + int callers, callees, idx; + + if (result == NULL) + { + /* Create the initial chain containing all the passed PCs. */ + + result = xmalloc (sizeof (*result) + sizeof (*result->call_site) + * (length - 1)); + result->length = length; + result->callers = result->callees = length; + memcpy (result->call_site, VEC_address (call_sitep, chain), + sizeof (*result->call_site) * length); + *resultp = result; + + if (entry_values_debug) + { + fprintf_unfiltered (gdb_stdlog, "tailcall: initial:"); + for (idx = 0; idx < length; idx++) + tailcall_dump (gdbarch, result->call_site[idx]); + fputc_unfiltered ('\n', gdb_stdlog); + } + + return; + } + + if (entry_values_debug) + { + fprintf_unfiltered (gdb_stdlog, "tailcall: compare:"); + for (idx = 0; idx < length; idx++) + tailcall_dump (gdbarch, VEC_index (call_sitep, chain, idx)); + fputc_unfiltered ('\n', gdb_stdlog); + } + + /* Intersect callers. */ + + callers = min (result->callers, length); + for (idx = 0; idx < callers; idx++) + if (result->call_site[idx] != VEC_index (call_sitep, chain, idx)) + { + result->callers = idx; + break; + } + + /* Intersect callees. */ + + callees = min (result->callees, length); + for (idx = 0; idx < callees; idx++) + if (result->call_site[result->length - 1 - idx] + != VEC_index (call_sitep, chain, length - 1 - idx)) + { + result->callees = idx; + break; + } + + if (entry_values_debug) + { + fprintf_unfiltered (gdb_stdlog, "tailcall: reduced:"); + for (idx = 0; idx < result->callers; idx++) + tailcall_dump (gdbarch, result->call_site[idx]); + fputs_unfiltered (" |", gdb_stdlog); + for (idx = 0; idx < result->callees; idx++) + tailcall_dump (gdbarch, result->call_site[result->length + - result->callees + idx]); + fputc_unfiltered ('\n', gdb_stdlog); + } + + if (result->callers == 0 && result->callees == 0) + { + /* There are no common callers or callees. It could be also a direct + call (which has length 0) with ambiguous possibility of an indirect + call - CALLERS == CALLEES == 0 is valid during the first allocation + but any subsequence processing of such entry means ambiguity. */ + xfree (result); + *resultp = NULL; + return; + } + + /* See call_site_find_chain_1 why there is no way to reach the bottom callee + PC again. In such case there must be two different code paths to reach + it, therefore some of the former determined intermediate PCs must differ + and the unambiguous chain gets shortened. */ + gdb_assert (result->callers + result->callees < result->length); +} + +/* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the + assumed frames between them use GDBARCH. Use depth first search so we can + keep single CHAIN of call_site's back to CALLER_PC. Function recursion + would have needless GDB stack overhead. Caller is responsible for xfree of + the returned result. Any unreliability results in thrown + NO_ENTRY_VALUE_ERROR. */ + +static struct call_site_chain * +call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc, + CORE_ADDR callee_pc) +{ + struct func_type *func_specific; + struct obstack addr_obstack; + struct cleanup *back_to_retval, *back_to_workdata; + struct call_site_chain *retval = NULL; + struct call_site *call_site; + + /* Mark CALL_SITEs so we do not visit the same ones twice. */ + htab_t addr_hash; + + /* CHAIN contains only the intermediate CALL_SITEs. Neither CALLER_PC's + call_site nor any possible call_site at CALLEE_PC's function is there. + Any CALL_SITE in CHAIN will be iterated to its siblings - via + TAIL_CALL_NEXT. This is inappropriate for CALLER_PC's call_site. */ + VEC (call_sitep) *chain = NULL; + + /* We are not interested in the specific PC inside the callee function. */ + callee_pc = get_pc_function_start (callee_pc); + if (callee_pc == 0) + throw_error (NO_ENTRY_VALUE_ERROR, _("Unable to find function for PC %s"), + paddress (gdbarch, callee_pc)); + + back_to_retval = make_cleanup (free_current_contents, &retval); + + obstack_init (&addr_obstack); + back_to_workdata = make_cleanup_obstack_free (&addr_obstack); + addr_hash = htab_create_alloc_ex (64, core_addr_hash, core_addr_eq, NULL, + &addr_obstack, hashtab_obstack_allocate, + NULL); + make_cleanup_htab_delete (addr_hash); + + make_cleanup (VEC_cleanup (call_sitep), &chain); + + /* Do not push CALL_SITE to CHAIN. Push there only the first tail call site + at the target's function. All the possible tail call sites in the + target's function will get iterated as already pushed into CHAIN via their + TAIL_CALL_NEXT. */ + call_site = call_site_for_pc (gdbarch, caller_pc); + + while (call_site) + { + CORE_ADDR target_func_addr; + struct call_site *target_call_site; + + /* CALLER_FRAME with registers is not available for tail-call jumped + frames. */ + target_func_addr = call_site_to_target_addr (gdbarch, call_site, NULL); + + if (target_func_addr == callee_pc) + { + chain_candidate (gdbarch, &retval, chain); + if (retval == NULL) + break; + + /* There is no way to reach CALLEE_PC again as we would prevent + entering it twice as being already marked in ADDR_HASH. */ + target_call_site = NULL; + } + else + { + struct symbol *target_func; + + target_func = func_addr_to_tail_call_list (gdbarch, target_func_addr); + target_call_site = TYPE_TAIL_CALL_LIST (SYMBOL_TYPE (target_func)); + } + + do + { + /* Attempt to visit TARGET_CALL_SITE. */ + + if (target_call_site) + { + void **slot; + + slot = htab_find_slot (addr_hash, &target_call_site->pc, INSERT); + if (*slot == NULL) + { + /* Successfully entered TARGET_CALL_SITE. */ + + *slot = &target_call_site->pc; + VEC_safe_push (call_sitep, chain, target_call_site); + break; + } + } + + /* Backtrack (without revisiting the originating call_site). Try the + callers's sibling; if there isn't any try the callers's callers's + sibling etc. */ + + target_call_site = NULL; + while (!VEC_empty (call_sitep, chain)) + { + call_site = VEC_pop (call_sitep, chain); + + gdb_assert (htab_find_slot (addr_hash, &call_site->pc, + NO_INSERT) != NULL); + htab_remove_elt (addr_hash, &call_site->pc); + + target_call_site = call_site->tail_call_next; + if (target_call_site) + break; + } + } + while (target_call_site); + + if (VEC_empty (call_sitep, chain)) + call_site = NULL; + else + call_site = VEC_last (call_sitep, chain); + } + + if (retval == NULL) + { + struct minimal_symbol *msym_caller, *msym_callee; + + msym_caller = lookup_minimal_symbol_by_pc (caller_pc); + msym_callee = lookup_minimal_symbol_by_pc (callee_pc); + throw_error (NO_ENTRY_VALUE_ERROR, + _("There are no unambiguously determinable intermediate " + "callers or callees between caller function \"%s\" at %s " + "and callee function \"%s\" at %s"), + (msym_caller == NULL + ? "???" : SYMBOL_PRINT_NAME (msym_caller)), + paddress (gdbarch, caller_pc), + (msym_callee == NULL + ? "???" : SYMBOL_PRINT_NAME (msym_callee)), + paddress (gdbarch, callee_pc)); + } + + do_cleanups (back_to_workdata); + discard_cleanups (back_to_retval); + return retval; +} + +/* Create and return call_site_chain for CALLER_PC and CALLEE_PC. All the + assumed frames between them use GDBARCH. If valid call_site_chain cannot be + constructed return NULL. Caller is responsible for xfree of the returned + result. */ + +struct call_site_chain * +call_site_find_chain (struct gdbarch *gdbarch, CORE_ADDR caller_pc, + CORE_ADDR callee_pc) +{ + volatile struct gdb_exception e; + struct call_site_chain *retval = NULL; + + TRY_CATCH (e, RETURN_MASK_ERROR) + { + retval = call_site_find_chain_1 (gdbarch, caller_pc, callee_pc); + } + if (e.reason < 0) + { + if (e.error == NO_ENTRY_VALUE_ERROR) + { + if (entry_values_debug) + exception_print (gdb_stdout, e); + + return NULL; + } + else + throw_exception (e); + } + return retval; +} + /* Fetch call_site_parameter from caller matching the parameters. FRAME is for callee. See DWARF_REG and FB_OFFSET description at struct dwarf_expr_context_funcs->push_dwarf_reg_entry_value. |