From c771017d22ae5f12f5a2e6d0dab6a07001857d7c Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Fri, 25 Nov 2011 10:43:58 +0000 Subject: [PATCH] backport: re PR debug/48190 ([regression?] Huge memory use while compiling qemu-0.4.0) gcc/ Backport from mainline: 2011-03-29 Richard Sandiford PR debug/48190 * dwarf2out.c (dw_loc_list_node): Add resolved_addr and replaced. (cached_dw_loc_list_def): New structure. (cached_dw_loc_list): New typedef. (cached_dw_loc_list_table): New variable. (cached_dw_loc_list_table_hash): New function. (cached_dw_loc_list_table_eq): Likewise. (add_location_or_const_value_attribute): Take a bool cache_p. Cache the list when the parameter is true. (gen_formal_parameter_die): Update caller. (gen_variable_die): Likewise. (dwarf2out_finish): Likewise. (dwarf2out_abstract_function): Nullify cached_dw_loc_list_table while generating debug info for the decl. (dwarf2out_function_decl): Clear cached_dw_loc_list_table. (dwarf2out_init): Initialize cached_dw_loc_list_table. (resolve_addr): Cache the result of resolving a chain of location lists. From: 2010-10-12 Jakub Jelinek * dwarf2out.c (dw_loc_list_node): Add emitted field. (output_loc_list): Return immediately if emitted is set, set it. From-SVN: r181717 --- gcc/ChangeLog | 29 ++++++++++ gcc/dwarf2out.c | 146 +++++++++++++++++++++++++++++++++++++++++------- 2 files changed, 156 insertions(+), 19 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 474517ab507d..8b6423c7e450 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,32 @@ +2011-11-25 Richard Sandiford + + Backport from mainline: + + 2011-03-29 Richard Sandiford + + PR debug/48190 + * dwarf2out.c (dw_loc_list_node): Add resolved_addr and replaced. + (cached_dw_loc_list_def): New structure. + (cached_dw_loc_list): New typedef. + (cached_dw_loc_list_table): New variable. + (cached_dw_loc_list_table_hash): New function. + (cached_dw_loc_list_table_eq): Likewise. + (add_location_or_const_value_attribute): Take a bool cache_p. + Cache the list when the parameter is true. + (gen_formal_parameter_die): Update caller. + (gen_variable_die): Likewise. + (dwarf2out_finish): Likewise. + (dwarf2out_abstract_function): Nullify cached_dw_loc_list_table + while generating debug info for the decl. + (dwarf2out_function_decl): Clear cached_dw_loc_list_table. + (dwarf2out_init): Initialize cached_dw_loc_list_table. + (resolve_addr): Cache the result of resolving a chain of + location lists. + + From: 2010-10-12 Jakub Jelinek + * dwarf2out.c (dw_loc_list_node): Add emitted field. + (output_loc_list): Return immediately if emitted is set, set it. + 2011-11-19 Eric Botcazou PR rtl-optimization/51187 diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c index 3daa315ebbe0..89c14637dca6 100644 --- a/gcc/dwarf2out.c +++ b/gcc/dwarf2out.c @@ -4254,6 +4254,12 @@ typedef struct GTY(()) dw_loc_list_struct { Only on head of list */ const char *section; /* Section this loclist is relative to */ dw_loc_descr_ref expr; + /* True if all addresses in this and subsequent lists are known to be + resolved. */ + bool resolved_addr; + /* True if this list has been replaced by dw_loc_next. */ + bool replaced; + bool emitted; } dw_loc_list_node; #if defined (DWARF2_DEBUGGING_INFO) || defined (DWARF2_UNWIND_INFO) @@ -5757,6 +5763,19 @@ typedef struct var_loc_list_def var_loc_list; /* Table of decl location linked lists. */ static GTY ((param_is (var_loc_list))) htab_t decl_loc_table; +/* A cached location list. */ +struct GTY (()) cached_dw_loc_list_def { + /* The DECL_UID of the decl that this entry describes. */ + unsigned int decl_id; + + /* The cached location list. */ + dw_loc_list_ref loc_list; +}; +typedef struct cached_dw_loc_list_def cached_dw_loc_list; + +/* Table of cached location lists. */ +static GTY ((param_is (cached_dw_loc_list))) htab_t cached_dw_loc_list_table; + /* A pointer to the base of a list of references to DIE's that are uniquely identified by their tag, presence/absence of children DIE's, and list of attribute/value pairs. */ @@ -6110,7 +6129,7 @@ static bool add_const_value_attribute (dw_die_ref, rtx); static void insert_int (HOST_WIDE_INT, unsigned, unsigned char *); static void insert_float (const_rtx, unsigned char *); static rtx rtl_for_decl_location (tree); -static bool add_location_or_const_value_attribute (dw_die_ref, tree, +static bool add_location_or_const_value_attribute (dw_die_ref, tree, bool, enum dwarf_attribute); static bool tree_add_const_value_attribute (dw_die_ref, tree); static bool tree_add_const_value_attribute_for_decl (dw_die_ref, tree); @@ -7729,6 +7748,24 @@ lookup_decl_loc (const_tree decl) htab_find_with_hash (decl_loc_table, decl, DECL_UID (decl)); } +/* Returns a hash value for X (which really is a cached_dw_loc_list_list). */ + +static hashval_t +cached_dw_loc_list_table_hash (const void *x) +{ + return (hashval_t) ((const cached_dw_loc_list *) x)->decl_id; +} + +/* Return nonzero if decl_id of cached_dw_loc_list X is the same as + UID of decl *Y. */ + +static int +cached_dw_loc_list_table_eq (const void *x, const void *y) +{ + return (((const cached_dw_loc_list *) x)->decl_id + == DECL_UID ((const_tree) y)); +} + /* Equate a DIE to a particular declaration. */ static void @@ -10353,6 +10390,10 @@ output_loc_list (dw_loc_list_ref list_head) { dw_loc_list_ref curr = list_head; + if (list_head->emitted) + return; + list_head->emitted = true; + ASM_OUTPUT_LABEL (asm_out_file, list_head->ll_symbol); /* Walk the location list, and output each range + expression. */ @@ -15918,15 +15959,22 @@ fortran_common (tree decl, HOST_WIDE_INT *value) these things can crop up in other ways also.) Note that one type of constant value which can be passed into an inlined function is a constant pointer. This can happen for example if an actual argument in an inlined - function call evaluates to a compile-time constant address. */ + function call evaluates to a compile-time constant address. + + CACHE_P is true if it is worth caching the location list for DECL, + so that future calls can reuse it rather than regenerate it from scratch. + This is true for BLOCK_NONLOCALIZED_VARS in inlined subroutines, + since we will need to refer to them each time the function is inlined. */ static bool -add_location_or_const_value_attribute (dw_die_ref die, tree decl, +add_location_or_const_value_attribute (dw_die_ref die, tree decl, bool cache_p, enum dwarf_attribute attr) { rtx rtl; dw_loc_list_ref list; var_loc_list *loc_list; + cached_dw_loc_list *cache; + void **slot; if (TREE_CODE (decl) == ERROR_MARK) return false; @@ -15962,7 +16010,34 @@ add_location_or_const_value_attribute (dw_die_ref die, tree decl, && add_const_value_attribute (die, rtl)) return true; } - list = loc_list_from_tree (decl, decl_by_reference_p (decl) ? 0 : 2); + /* If this decl is from BLOCK_NONLOCALIZED_VARS, we might need its + list several times. See if we've already cached the contents. */ + list = NULL; + if (loc_list == NULL || cached_dw_loc_list_table == NULL) + cache_p = false; + if (cache_p) + { + cache = (cached_dw_loc_list *) + htab_find_with_hash (cached_dw_loc_list_table, decl, DECL_UID (decl)); + if (cache) + list = cache->loc_list; + } + if (list == NULL) + { + list = loc_list_from_tree (decl, decl_by_reference_p (decl) ? 0 : 2); + /* It is usually worth caching this result if the decl is from + BLOCK_NONLOCALIZED_VARS and if the list has at least two elements. */ + if (cache_p && list && list->dw_loc_next) + { + slot = htab_find_slot_with_hash (cached_dw_loc_list_table, decl, + DECL_UID (decl), INSERT); + cache = (cached_dw_loc_list *) + ggc_alloc_cleared (sizeof (cached_dw_loc_list)); + cache->decl_id = DECL_UID (decl); + cache->loc_list = list; + *slot = cache; + } + } if (list) { add_AT_location_description (die, attr, list); @@ -17530,7 +17605,7 @@ gen_formal_parameter_die (tree node, tree origin, bool emit_name_p, equate_decl_number_to_die (node, parm_die); if (! DECL_ABSTRACT (node_or_origin)) add_location_or_const_value_attribute (parm_die, node_or_origin, - DW_AT_location); + node == NULL, DW_AT_location); break; @@ -17710,6 +17785,7 @@ dwarf2out_abstract_function (tree decl) tree context; int was_abstract; htab_t old_decl_loc_table; + htab_t old_cached_dw_loc_list_table; /* Make sure we have the actual abstract inline, not a clone. */ decl = DECL_ORIGIN (decl); @@ -17723,7 +17799,9 @@ dwarf2out_abstract_function (tree decl) DIE. Be sure to not clobber the outer location table nor use it or we would get locations in abstract instantces. */ old_decl_loc_table = decl_loc_table; + old_cached_dw_loc_list_table = cached_dw_loc_list_table; decl_loc_table = NULL; + cached_dw_loc_list_table = NULL; /* Be sure we've emitted the in-class declaration DIE (if any) first, so we don't get confused by DECL_ABSTRACT. */ @@ -17748,6 +17826,7 @@ dwarf2out_abstract_function (tree decl) current_function_decl = save_fn; decl_loc_table = old_decl_loc_table; + cached_dw_loc_list_table = old_cached_dw_loc_list_table; pop_cfun (); } @@ -18429,9 +18508,8 @@ gen_variable_die (tree decl, tree origin, dw_die_ref context_die) && !TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl_or_origin))) defer_location (decl_or_origin, var_die); else - add_location_or_const_value_attribute (var_die, - decl_or_origin, - DW_AT_location); + add_location_or_const_value_attribute (var_die, decl_or_origin, + decl == NULL, DW_AT_location); add_pubname (decl_or_origin, var_die); } else @@ -20037,6 +20115,7 @@ dwarf2out_function_decl (tree decl) dwarf2out_decl (decl); htab_empty (decl_loc_table); + htab_empty (cached_dw_loc_list_table); } /* Output a marker (i.e. a label) for the beginning of the generated code for @@ -20637,6 +20716,11 @@ dwarf2out_init (const char *filename ATTRIBUTE_UNUSED) decl_loc_table = htab_create_ggc (10, decl_loc_table_hash, decl_loc_table_eq, NULL); + /* Allocate the cached_dw_loc_list_table. */ + cached_dw_loc_list_table + = htab_create_ggc (10, cached_dw_loc_list_table_hash, + cached_dw_loc_list_table_eq, NULL); + /* Allocate the initial hunk of the decl_scope_table. */ decl_scope_table = VEC_alloc (tree, gc, 256); @@ -21261,30 +21345,53 @@ resolve_addr (dw_die_ref die) { dw_die_ref c; dw_attr_ref a; - dw_loc_list_ref *curr; + dw_loc_list_ref *curr, *start, loc; unsigned ix; for (ix = 0; VEC_iterate (dw_attr_node, die->die_attr, ix, a); ix++) switch (AT_class (a)) { case dw_val_class_loc_list: - curr = AT_loc_list_ptr (a); - while (*curr) + start = curr = AT_loc_list_ptr (a); + loc = *curr; + gcc_assert (loc); + /* The same list can be referenced more than once. See if we have + already recorded the result from a previous pass. */ + if (loc->replaced) + *curr = loc->dw_loc_next; + else if (!loc->resolved_addr) { - if (!resolve_addr_in_expr ((*curr)->expr)) + /* As things stand, we do not expect or allow one die to + reference a suffix of another die's location list chain. + References must be identical or completely separate. + There is therefore no need to cache the result of this + pass on any list other than the first; doing so + would lead to unnecessary writes. */ + while (*curr) { - dw_loc_list_ref next = (*curr)->dw_loc_next; - if (next && (*curr)->ll_symbol) + gcc_assert (!(*curr)->replaced && !(*curr)->resolved_addr); + if (!resolve_addr_in_expr ((*curr)->expr)) { - gcc_assert (!next->ll_symbol); - next->ll_symbol = (*curr)->ll_symbol; + dw_loc_list_ref next = (*curr)->dw_loc_next; + if (next && (*curr)->ll_symbol) + { + gcc_assert (!next->ll_symbol); + next->ll_symbol = (*curr)->ll_symbol; + } + *curr = next; } - *curr = next; + else + curr = &(*curr)->dw_loc_next; } + if (loc == *start) + loc->resolved_addr = 1; else - curr = &(*curr)->dw_loc_next; + { + loc->replaced = 1; + loc->dw_loc_next = *start; + } } - if (!AT_loc_list (a)) + if (!*start) { remove_AT (die, a->dw_attr); ix--; @@ -21344,6 +21451,7 @@ dwarf2out_finish (const char *filename) add_location_or_const_value_attribute ( VEC_index (deferred_locations, deferred_locations_list, i)->die, VEC_index (deferred_locations, deferred_locations_list, i)->variable, + false, DW_AT_location); } -- 2.47.2