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Speed up bfd_dwarf2_find_line.

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* dwarf2.c (struct dwarf2_debug): Add new fields to support function and variable info hash tables. Add last_comp_unit, info_hash_count, funcinfo_hash_table, varinfo_hash_table, hash_units_head.
  (struct comp_unit): Add prev_unit, cached.
  (struct info_list_node, struct info_hash_entry, struct info_hash_table): New.
  (info_hash_table_newfunc, create_info_hash_table, insert_info_hash_table, lookup_info_hash_table): New functions implementing function and variable info hash tables.
  (scan_unit_for_symbols): Add checks to make sure hash tables are consistent with compilation units.
  (comp_unit_maybe_decode_line_info): New function.
  (comp_unit_find_line): Use comp_unit_maybe_decode_line_info.
  (reverse_funcinfo_list, reverse_varinfo_list, comp_unit_hash_info, info_hash_lookup_funcinfo, info_hash_lookup_varinfo, stash_maybe_update_info_hash_table, stash_verify_info_hash_table, stash_maybe_enable_info_hash_tables, stash_find_line_fast): New functions. Make use of info hash tables to speed up bfd_dwarf2_find_line.
  (find_line): Use hash table for faster lookup if it is turned on.
  Also add code to maintain bi-directional link in comp units.
This commit is contained in:
Nick Clifton 2007-07-26 08:31:03 +00:00
parent 353c55748a
commit bd210d54db
2 changed files with 578 additions and 31 deletions
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25
bfd/ChangeLog
View file

@ -1,3 +1,28 @@
2007-07-26 Doug Kwan <dougkwan@google.com>
Speed up bfd_dwarf2_find_line.
* dwarf2.c (struct dwarf2_debug): Add new fields to support function
and variable info hash tables. Add last_comp_unit, info_hash_count,
funcinfo_hash_table, varinfo_hash_table, hash_units_head.
(struct comp_unit): Add prev_unit, cached.
(struct info_list_node, struct info_hash_entry,
struct info_hash_table): New.
(info_hash_table_newfunc, create_info_hash_table,
insert_info_hash_table, lookup_info_hash_table): New functions
implementing function and variable info hash tables.
(scan_unit_for_symbols): Add checks to make sure hash tables are
consistent with compilation units.
(comp_unit_maybe_decode_line_info): New function.
(comp_unit_find_line): Use comp_unit_maybe_decode_line_info.
(reverse_funcinfo_list, reverse_varinfo_list, comp_unit_hash_info,
info_hash_lookup_funcinfo, info_hash_lookup_varinfo,
stash_maybe_update_info_hash_table, stash_verify_info_hash_table,
stash_maybe_enable_info_hash_tables, stash_find_line_fast): New
functions. Make use of info hash tables to speed up
bfd_dwarf2_find_line.
(find_line): Use hash table for faster lookup if it is turned on.
Also add code to maintain bi-directional link in comp units.
2007-07-25 Michael Snyder <msnyder@access-company.com>
* coffgen.c (_bfd_coff_get_external_symbols): Nothing to be done

584
bfd/dwarf2.c
View file

@ -86,6 +86,9 @@ struct dwarf2_debug
/* A list of all previously read comp_units. */
struct comp_unit *all_comp_units;
/* Last comp unit in list above. */
struct comp_unit *last_comp_unit;
/* The next unread compilation unit within the .debug_info section.
Zero indicates that the .debug_info section has not been loaded
into a buffer yet. */
@ -139,6 +142,27 @@ struct dwarf2_debug
/* Array of loadable sections. */
struct loadable_section *loadable_sections;
/* Number of times find_line is called. This is used in
the heuristic for enabling the info hash tables. */
int info_hash_count;
#define STASH_INFO_HASH_TRIGGER 100
/* Hash table mapping symbol names to function infos. */
struct info_hash_table *funcinfo_hash_table;
/* Hash table mapping symbol names to variable infos. */
struct info_hash_table *varinfo_hash_table;
/* Head of comp_unit list in the last hash table update. */
struct comp_unit *hash_units_head;
/* Status of info hash. */
int info_hash_status;
#define STASH_INFO_HASH_OFF 0
#define STASH_INFO_HASH_ON 1
#define STASH_INFO_HASH_DISABLED 2
};
struct arange
@ -156,6 +180,10 @@ struct comp_unit
/* Chain the previously read compilation units. */
struct comp_unit *next_unit;
/* Likewise, chain the compilation unit read after this one.
The comp units are stored in reversed reading order. */
struct comp_unit *prev_unit;
/* Keep the bfd convenient (for memory allocation). */
bfd *abfd;
@ -212,6 +240,9 @@ struct comp_unit
/* Base address for this unit - from DW_AT_low_pc attribute of
DW_TAG_compile_unit DIE */
bfd_vma base_address;
/* TRUE if symbols are cached in hash table for faster lookup by name. */
bfd_boolean cached;
};
/* This data structure holds the information of an abbrev. */
@ -238,6 +269,126 @@ struct attr_abbrev
#define ATTR_ALLOC_CHUNK 4
#endif
/* Variable and function hash tables. This is used to speed up look-up
in lookup_symbol_in_var_table() and lookup_symbol_in_function_table().
In order to share code between variable and function infos, we use
a list of untyped pointer for all variable/function info associated with
a symbol. We waste a bit of memory for list with one node but that
simplifies the code. */
struct info_list_node
{
struct info_list_node *next;
void *info;
};
/* Info hash entry. */
struct info_hash_entry
{
struct bfd_hash_entry root;
struct info_list_node *head;
};
struct info_hash_table
{
struct bfd_hash_table base;
};
/* Function to create a new entry in info hash table. */
static struct bfd_hash_entry *
info_hash_table_newfunc (struct bfd_hash_entry *entry,
struct bfd_hash_table *table,
const char *string)
{
struct info_hash_entry *ret = (struct info_hash_entry *) entry;
/* Allocate the structure if it has not already been allocated by a
derived class. */
if (ret == NULL)
{
ret = bfd_hash_allocate (table, sizeof (* ret));
if (ret == NULL)
return NULL;
}
/* Call the allocation method of the base class. */
ret = ((struct info_hash_entry *)
bfd_hash_newfunc ((struct bfd_hash_entry *) ret, table, string));
/* Initialize the local fields here. */
if (ret)
ret->head = NULL;
return (struct bfd_hash_entry *) ret;
}
/* Function to create a new info hash table. It returns a pointer to the
newly created table or NULL if there is any error. We need abfd
solely for memory allocation. */
static struct info_hash_table *
create_info_hash_table (bfd *abfd)
{
struct info_hash_table *hash_table;
hash_table = bfd_alloc (abfd, sizeof (struct info_hash_table));
if (!hash_table)
return hash_table;
if (!bfd_hash_table_init (&hash_table->base, info_hash_table_newfunc,
sizeof (struct info_hash_entry)))
{
bfd_release (abfd, hash_table);
return NULL;
}
return hash_table;
}
/* Insert an info entry into an info hash table. We do not check of
duplicate entries. Also, the caller need to guarantee that the
right type of info in inserted as info is passed as a void* pointer.
This function returns true if there is no error. */
static bfd_boolean
insert_info_hash_table (struct info_hash_table *hash_table,
const char *key,
void *info,
bfd_boolean copy_p)
{
struct info_hash_entry *entry;
struct info_list_node *node;
entry = (struct info_hash_entry*) bfd_hash_lookup (&hash_table->base,
key, TRUE, copy_p);
if (!entry)
return FALSE;
node = bfd_hash_allocate (&hash_table->base, sizeof (*node));
if (!node)
return FALSE;
node->info = info;
node->next = entry->head;
entry->head = node;
return TRUE;
}
/* Look up an info entry list from an info hash table. Return NULL
if there is none. */
static struct info_list_node *
lookup_info_hash_table (struct info_hash_table *hash_table, const char *key)
{
struct info_hash_entry *entry;
entry = (struct info_hash_entry*) bfd_hash_lookup (&hash_table->base, key,
FALSE, FALSE);
return entry ? entry->head : NULL;
}
/* VERBATIM
The following function up to the END VERBATIM mark are
copied directly from dwarf2read.c. */
@ -1710,6 +1861,7 @@ scan_unit_for_symbols (struct comp_unit *unit)
func->tag = abbrev->tag;
func->prev_func = unit->function_table;
unit->function_table = func;
BFD_ASSERT (!unit->cached);
if (func->tag == DW_TAG_inlined_subroutine)
for (i = nesting_level - 1; i >= 1; i--)
@ -1731,6 +1883,7 @@ scan_unit_for_symbols (struct comp_unit *unit)
var->stack = 1;
var->prev_var = unit->variable_table;
unit->variable_table = var;
BFD_ASSERT (!unit->cached);
}
/* No inline function in scope at this nesting level. */
@ -2125,21 +2278,13 @@ comp_unit_find_nearest_line (struct comp_unit *unit,
return line_p || func_p;
}
/* If UNIT contains SYM at ADDR, set the output parameters to the
values for the line containing SYM. The output parameters,
FILENAME_PTR, and LINENUMBER_PTR, are pointers to the objects to be
filled in.
Return TRUE if UNIT contains SYM, and no errors were encountered;
/* Check to see if line info is already decoded in a comp_unit.
If not, decode it. Returns TRUE if no errors were encountered;
FALSE otherwise. */
static bfd_boolean
comp_unit_find_line (struct comp_unit *unit,
asymbol *sym,
bfd_vma addr,
const char **filename_ptr,
unsigned int *linenumber_ptr,
struct dwarf2_debug *stash)
comp_unit_maybe_decode_line_info (struct comp_unit *unit,
struct dwarf2_debug *stash)
{
if (unit->error)
return FALSE;
@ -2168,14 +2313,131 @@ comp_unit_find_line (struct comp_unit *unit,
}
}
return TRUE;
}
/* If UNIT contains SYM at ADDR, set the output parameters to the
values for the line containing SYM. The output parameters,
FILENAME_PTR, and LINENUMBER_PTR, are pointers to the objects to be
filled in.
Return TRUE if UNIT contains SYM, and no errors were encountered;
FALSE otherwise. */
static bfd_boolean
comp_unit_find_line (struct comp_unit *unit,
asymbol *sym,
bfd_vma addr,
const char **filename_ptr,
unsigned int *linenumber_ptr,
struct dwarf2_debug *stash)
{
if (!comp_unit_maybe_decode_line_info (unit, stash))
return FALSE;
if (sym->flags & BSF_FUNCTION)
return lookup_symbol_in_function_table (unit, sym, addr,
filename_ptr,
linenumber_ptr);
else
return lookup_symbol_in_variable_table (unit, sym, addr,
filename_ptr,
linenumber_ptr);
return lookup_symbol_in_variable_table (unit, sym, addr,
filename_ptr,
linenumber_ptr);
}
static struct funcinfo *
reverse_funcinfo_list (struct funcinfo *head)
{
struct funcinfo *rhead;
struct funcinfo *temp;
for (rhead = NULL; head; head = temp)
{
temp = head->prev_func;
head->prev_func = rhead;
rhead = head;
}
return rhead;
}
static struct varinfo *
reverse_varinfo_list (struct varinfo *head)
{
struct varinfo *rhead;
struct varinfo *temp;
for (rhead = NULL; head; head = temp)
{
temp = head->prev_var;
head->prev_var = rhead;
rhead = head;
}
return rhead;
}
/* Extract all interesting funcinfos and varinfos of a compilation
unit into hash tables for faster lookup. Returns TRUE if no
errors were enountered; FALSE otherwise. */
static bfd_boolean
comp_unit_hash_info (struct dwarf2_debug *stash,
struct comp_unit *unit,
struct info_hash_table *funcinfo_hash_table,
struct info_hash_table *varinfo_hash_table)
{
struct funcinfo* each_func;
struct varinfo* each_var;
bfd_boolean okay = TRUE;
BFD_ASSERT (stash->info_hash_status != STASH_INFO_HASH_DISABLED);
if (!comp_unit_maybe_decode_line_info (unit, stash))
return FALSE;
BFD_ASSERT (!unit->cached);
/* To preserve the original search order, we went to visit the function
infos in the reversed order of the list. However, making the list
bi-directional use quite a bit of extra memory. So we reverse
the list first, traverse the list in the now reversed order and
finally reverse the list again to get back the original order. */
unit->function_table = reverse_funcinfo_list (unit->function_table);
for (each_func = unit->function_table;
each_func && okay;
each_func = each_func->prev_func)
{
/* Skip nameless functions. */
if (each_func->name)
/* There is no need to copy name string into hash table as
name string is either in the dwarf string buffer or
info in the stash. */
okay = insert_info_hash_table (funcinfo_hash_table, each_func->name,
(void*) each_func, FALSE);
}
unit->function_table = reverse_funcinfo_list (unit->function_table);
if (!okay)
return FALSE;
/* We do the same for variable infos. */
unit->variable_table = reverse_varinfo_list (unit->variable_table);
for (each_var = unit->variable_table;
each_var && okay;
each_var = each_var->prev_var)
{
/* Skip stack vars and vars with no files or names. */
if (each_var->stack == 0
&& each_var->file != NULL
&& each_var->name != NULL)
/* There is no need to copy name string into hash table as
name string is either in the dwarf string buffer or
info in the stash. */
okay = insert_info_hash_table (varinfo_hash_table, each_var->name,
(void*) each_var, FALSE);
}
unit->variable_table = reverse_varinfo_list (unit->variable_table);
unit->cached = TRUE;
return okay;
}
/* Locate a section in a BFD containing debugging info. The search starts
@ -2302,6 +2564,231 @@ place_sections (bfd *abfd, struct dwarf2_debug *stash)
return TRUE;
}
/* Look up a funcinfo by name using the given info hash table. If found,
also update the locations pointed to by filename_ptr and linenumber_ptr.
This function returns TRUE if a funcinfo that matches the given symbol
and address is found with any error; otherwise it returns FALSE. */
static bfd_boolean
info_hash_lookup_funcinfo (struct info_hash_table *hash_table,
asymbol *sym,
bfd_vma addr,
const char **filename_ptr,
unsigned int *linenumber_ptr)
{
struct funcinfo* each_func;
struct funcinfo* best_fit = NULL;
struct info_list_node *node;
struct arange *arange;
const char *name = bfd_asymbol_name (sym);
asection *sec = bfd_get_section (sym);
for (node = lookup_info_hash_table (hash_table, name);
node;
node = node->next)
{
each_func = node->info;
for (arange = &each_func->arange;
arange;
arange = arange->next)
{
if ((!each_func->sec || each_func->sec == sec)
&& addr >= arange->low
&& addr < arange->high
&& (!best_fit
|| ((arange->high - arange->low)
< (best_fit->arange.high - best_fit->arange.low))))
best_fit = each_func;
}
}
if (best_fit)
{
best_fit->sec = sec;
*filename_ptr = best_fit->file;
*linenumber_ptr = best_fit->line;
return TRUE;
}
return FALSE;
}
/* Look up a varinfo by name using the given info hash table. If found,
also update the locations pointed to by filename_ptr and linenumber_ptr.
This function returns TRUE if a varinfo that matches the given symbol
and address is found with any error; otherwise it returns FALSE. */
static bfd_boolean
info_hash_lookup_varinfo (struct info_hash_table *hash_table,
asymbol *sym,
bfd_vma addr,
const char **filename_ptr,
unsigned int *linenumber_ptr)
{
const char *name = bfd_asymbol_name (sym);
asection *sec = bfd_get_section (sym);
struct varinfo* each;
struct info_list_node *node;
for (node = lookup_info_hash_table (hash_table, name);
node;
node = node->next)
{
each = node->info;
if (each->addr == addr
&& (!each->sec || each->sec == sec))
{
each->sec = sec;
*filename_ptr = each->file;
*linenumber_ptr = each->line;
return TRUE;
}
}
return FALSE;
}
/* Update the funcinfo and varinfo info hash tables if they are
not up to date. Returns TRUE if there is no error; otherwise
returns FALSE and disable the info hash tables. */
static bfd_boolean
stash_maybe_update_info_hash_tables (struct dwarf2_debug *stash)
{
struct comp_unit *each;
/* Exit if hash tables are up-to-date. */
if (stash->all_comp_units == stash->hash_units_head)
return TRUE;
if (stash->hash_units_head)
each = stash->hash_units_head->prev_unit;
else
each = stash->last_comp_unit;
while (each)
{
if (!comp_unit_hash_info (stash, each, stash->funcinfo_hash_table,
stash->varinfo_hash_table))
{
stash->info_hash_status = STASH_INFO_HASH_DISABLED;
return FALSE;
}
each = each->prev_unit;
}
stash->hash_units_head = stash->all_comp_units;
return TRUE;
}
/* Check consistency of info hash tables. This is for debugging only. */
static void ATTRIBUTE_UNUSED
stash_verify_info_hash_table (struct dwarf2_debug *stash)
{
struct comp_unit *each_unit;
struct funcinfo *each_func;
struct varinfo *each_var;
struct info_list_node *node;
bfd_boolean found;
for (each_unit = stash->all_comp_units;
each_unit;
each_unit = each_unit->next_unit)
{
for (each_func = each_unit->function_table;
each_func;
each_func = each_func->prev_func)
{
if (!each_func->name)
continue;
node = lookup_info_hash_table (stash->funcinfo_hash_table,
each_func->name);
BFD_ASSERT (node);
found = FALSE;
while (node && !found)
{
found = node->info == each_func;
node = node->next;
}
BFD_ASSERT (found);
}
for (each_var = each_unit->variable_table;
each_var;
each_var = each_var->prev_var)
{
if (!each_var->name || !each_var->file || each_var->stack)
continue;
node = lookup_info_hash_table (stash->varinfo_hash_table,
each_var->name);
BFD_ASSERT (node);
found = FALSE;
while (node && !found)
{
found = node->info == each_var;
node = node->next;
}
BFD_ASSERT (found);
}
}
}
/* Check to see if we want to enable the info hash tables, which consume
quite a bit of memory. Currently we only check the number times
bfd_dwarf2_find_line is called. In the future, we may also want to
take the number of symbols into account. */
static void
stash_maybe_enable_info_hash_tables (bfd *abfd, struct dwarf2_debug *stash)
{
BFD_ASSERT (stash->info_hash_status == STASH_INFO_HASH_OFF);
if (stash->info_hash_count++ < STASH_INFO_HASH_TRIGGER)
return;
/* FIXME: Maybe we should check the reduce_memory_overheads
and optimize fields in the bfd_link_info structure ? */
/* Create hash tables. */
stash->funcinfo_hash_table = create_info_hash_table (abfd);
stash->varinfo_hash_table = create_info_hash_table (abfd);
if (!stash->funcinfo_hash_table || !stash->varinfo_hash_table)
{
/* Turn off info hashes if any allocation above fails. */
stash->info_hash_status = STASH_INFO_HASH_DISABLED;
return;
}
/* We need a forced update so that the info hash tables will
be created even though there is no compilation unit. That
happens if STASH_INFO_HASH_TRIGGER is 0. */
stash_maybe_update_info_hash_tables (stash);
stash->info_hash_status = STASH_INFO_HASH_ON;
}
/* Find the file and line associated with a symbol and address using the
info hash tables of a stash. If there is a match, the function returns
TRUE and update the locations pointed to by filename_ptr and linenumber_ptr;
otherwise it returns FALSE. */
static bfd_boolean
stash_find_line_fast (struct dwarf2_debug *stash,
asymbol *sym,
bfd_vma addr,
const char **filename_ptr,
unsigned int *linenumber_ptr)
{
BFD_ASSERT (stash->info_hash_status == STASH_INFO_HASH_ON);
if (sym->flags & BSF_FUNCTION)
return info_hash_lookup_funcinfo (stash->funcinfo_hash_table, sym, addr,
filename_ptr, linenumber_ptr);
return info_hash_lookup_varinfo (stash->varinfo_hash_table, sym, addr,
filename_ptr, linenumber_ptr);
}
/* Find the source code location of SYMBOL. If SYMBOL is NULL
then find the nearest source code location corresponding to
the address SECTION + OFFSET.
@ -2468,23 +2955,53 @@ find_line (bfd *abfd,
stash->inliner_chain = NULL;
/* Check the previously read comp. units first. */
for (each = stash->all_comp_units; each; each = each->next_unit)
if (do_line)
{
if (do_line)
found = (((symbol->flags & BSF_FUNCTION) == 0
|| comp_unit_contains_address (each, addr))
&& comp_unit_find_line (each, symbol, addr,
filename_ptr, linenumber_ptr,
stash));
/* The info hash tables use quite a bit of memory. We may not want to
always use them. We use some heuristics to decide if and when to
turn it on. */
if (stash->info_hash_status == STASH_INFO_HASH_OFF)
stash_maybe_enable_info_hash_tables (abfd, stash);
/* Keep info hash table up to date if they are available. Note that we
may disable the hash tables if there is any error duing update. */
if (stash->info_hash_status == STASH_INFO_HASH_ON)
stash_maybe_update_info_hash_tables (stash);
if (stash->info_hash_status == STASH_INFO_HASH_ON)
{
found = stash_find_line_fast (stash, symbol, addr, filename_ptr,
linenumber_ptr);
if (found)
goto done;
}
else
found = (comp_unit_contains_address (each, addr)
&& comp_unit_find_nearest_line (each, addr,
filename_ptr,
functionname_ptr,
linenumber_ptr,
stash));
if (found)
goto done;
{
/* Check the previously read comp. units first. */
for (each = stash->all_comp_units; each; each = each->next_unit)
if ((symbol->flags & BSF_FUNCTION) == 0
|| comp_unit_contains_address (each, addr))
{
found = comp_unit_find_line (each, symbol, addr, filename_ptr,
linenumber_ptr, stash);
if (found)
goto done;
}
}
}
else
{
for (each = stash->all_comp_units; each; each = each->next_unit)
{
found = (comp_unit_contains_address (each, addr)
&& comp_unit_find_nearest_line (each, addr,
filename_ptr,
functionname_ptr,
linenumber_ptr,
stash));
if (found)
goto done;
}
}
/* The DWARF2 spec says that the initial length field, and the
@ -2551,6 +3068,11 @@ find_line (bfd *abfd,
if (each)
{
if (stash->all_comp_units)
stash->all_comp_units->prev_unit = each;
else
stash->last_comp_unit = each;
each->next_unit = stash->all_comp_units;
stash->all_comp_units = each;