On Tue, 4 Oct 2011, Jan Hubicka wrote:
> > From: Andi Kleen <a...@linux.intel.com>
> >
> > Currently when reading in LTO sections from ld -r files they can
> > get randomly reordered based on hash tables and random IDs.
> > This causes reordering later when the final code is generated and
> > also makes crashes harder to reproduce.
> >
> > This patch maintains explicit lists based on the input order and uses
> > those lists to preserve that order when starting the rest of the
> > LTO passes.
> >
> > This is the first step to working -fno-toplevel-reorder for
> > LTO. But this needs more changes because the LTO partitioner
> > can still reorder.
> >
> > This add two lists: one for the section and another one for
> > the file_decl_datas. This is needed because the sections are
> > walked twice through different data structures.
> >
> > In addition some code becomes slightly cleaner because we don't need
> > to pass state through abstract callbacks anymore, but
> > can just use direct type safe calls.
> >
> > Passes LTO bootstrap and testsuite on x86_64-linux. Ok?
>
> Note that this is also needed to make lto-symtab decisions consistent with
> linker
> decisions. So it makes a lot of sense to me, but I can't approve it.
> I was running into funny cases where things got resolved differently on
> openoffice, so hopefully this will solve it.
Well, I'm not sure we should jump through too much hoops to make
-flto work with -fno-toplevel-reorder. Simply because I think nothing
defines any "toplevel order" for multiple object files. So, I think
both ld and gcc/collect2 need to first document they will never
break toplevel order (what about ld with -ffunction-sections and
-gc-sections? Or -relax?)
Richard.
>
> Honza
> >
> > gcc/lto/:
> >
> > 2011-10-02 Andi Kleen <a...@linux.intel.com>
> >
> > * lto-object.c (lto_obj_add_section_data): Add list.
> > (lto_obj_add_section): Fill in list.
> > (ltoobj_build_section_table): Pass through list.
> > * lto.c (file_data_list): Declare.
> > (create_subid_section_table): Pass arguments directly.
> > Fill in list of file_datas.
> > (lwstate): Delete.
> > (lto_create_files_from_ids): Pass in direct arguments.
> > Don't maintain list.
> > (lto_file_read): Use explicit section and file data lists.
> > (lto_read_all_file_options): Pass in section_list.
> > * lto.h (lto_obj_build_section_table): Add list.
> > (lto_section_slot): Add next.
> > (lto_section_list): Declare.
> >
> > diff --git a/gcc/lto/lto-object.c b/gcc/lto/lto-object.c
> > index 3be58de..daf3bd0 100644
> > --- a/gcc/lto/lto-object.c
> > +++ b/gcc/lto/lto-object.c
> > @@ -204,6 +204,8 @@ struct lto_obj_add_section_data
> > htab_t section_hash_table;
> > /* The offset of this file. */
> > off_t base_offset;
> > + /* List in linker order */
> > + struct lto_section_list *list;
> > };
> >
> > /* This is called for each section in the file. */
> > @@ -218,6 +220,7 @@ lto_obj_add_section (void *data, const char *name,
> > off_t offset,
> > char *new_name;
> > struct lto_section_slot s_slot;
> > void **slot;
> > + struct lto_section_list *list = loasd->list;
> >
> > if (strncmp (name, LTO_SECTION_NAME_PREFIX,
> > strlen (LTO_SECTION_NAME_PREFIX)) != 0)
> > @@ -228,12 +231,21 @@ lto_obj_add_section (void *data, const char *name,
> > off_t offset,
> > slot = htab_find_slot (section_hash_table, &s_slot, INSERT);
> > if (*slot == NULL)
> > {
> > - struct lto_section_slot *new_slot = XNEW (struct lto_section_slot);
> > + struct lto_section_slot *new_slot = XCNEW (struct lto_section_slot);
> >
> > new_slot->name = new_name;
> > new_slot->start = loasd->base_offset + offset;
> > new_slot->len = length;
> > *slot = new_slot;
> > +
> > + if (list != NULL)
> > + {
> > + if (!list->first)
> > + list->first = new_slot;
> > + if (list->last)
> > + list->last->next = new_slot;
> > + list->last = new_slot;
> > + }
> > }
> > else
> > {
> > @@ -248,7 +260,7 @@ lto_obj_add_section (void *data, const char *name,
> > off_t offset,
> > the start and size of each section in the .o file. */
> >
> > htab_t
> > -lto_obj_build_section_table (lto_file *lto_file)
> > +lto_obj_build_section_table (lto_file *lto_file, struct lto_section_list
> > *list)
> > {
> > struct lto_simple_object *lo = (struct lto_simple_object *) lto_file;
> > htab_t section_hash_table;
> > @@ -261,6 +273,7 @@ lto_obj_build_section_table (lto_file *lto_file)
> > gcc_assert (lo->sobj_r != NULL && lo->sobj_w == NULL);
> > loasd.section_hash_table = section_hash_table;
> > loasd.base_offset = lo->base.offset;
> > + loasd.list = list;
> > errmsg = simple_object_find_sections (lo->sobj_r, lto_obj_add_section,
> > &loasd, &err);
> > if (errmsg != NULL)
> > diff --git a/gcc/lto/lto.c b/gcc/lto/lto.c
> > index 778e33e..a77eeb4 100644
> > --- a/gcc/lto/lto.c
> > +++ b/gcc/lto/lto.c
> > @@ -1052,6 +1052,12 @@ lto_resolution_read (splay_tree file_ids, FILE
> > *resolution, lto_file *file)
> > }
> > }
> >
> > +/* List of file_decl_datas */
> > +struct file_data_list
> > + {
> > + struct lto_file_decl_data *first, *last;
> > + };
> > +
> > /* Is the name for a id'ed LTO section? */
> >
> > static int
> > @@ -1068,11 +1074,10 @@ lto_section_with_id (const char *name, unsigned
> > HOST_WIDE_INT *id)
> > /* Create file_data of each sub file id */
> >
> > static int
> > -create_subid_section_table (void **slot, void *data)
> > +create_subid_section_table (struct lto_section_slot *ls, splay_tree
> > file_ids,
> > + struct file_data_list *list)
> > {
> > struct lto_section_slot s_slot, *new_slot;
> > - struct lto_section_slot *ls = *(struct lto_section_slot **)slot;
> > - splay_tree file_ids = (splay_tree)data;
> > unsigned HOST_WIDE_INT id;
> > splay_tree_node nd;
> > void **hash_slot;
> > @@ -1095,6 +1100,13 @@ create_subid_section_table (void **slot, void *data)
> > file_data->id = id;
> > file_data->section_hash_table = lto_obj_create_section_hash_table
> > ();;
> > lto_splay_tree_insert (file_ids, id, file_data);
> > +
> > + /* Maintain list in linker order */
> > + if (!list->first)
> > + list->first = file_data;
> > + if (list->last)
> > + list->last->next = file_data;
> > + list->last = file_data;
> > }
> >
> > /* Copy section into sub module hash table */
> > @@ -1129,27 +1141,17 @@ lto_file_finalize (struct lto_file_decl_data
> > *file_data, lto_file *file)
> > lto_free_section_data (file_data, LTO_section_decls, NULL, data, len);
> > }
> >
> > -struct lwstate
> > -{
> > - lto_file *file;
> > - struct lto_file_decl_data **file_data;
> > - int *count;
> > -};
> > -
> > -/* Traverse ids and create a list of file_datas out of it. */
> > +/* Finalize FILE_DATA in FILE and increase COUNT. */
> >
> > -static int lto_create_files_from_ids (splay_tree_node node, void *data)
> > +static int
> > +lto_create_files_from_ids (lto_file *file, struct lto_file_decl_data
> > *file_data,
> > + int *count)
> > {
> > - struct lwstate *lw = (struct lwstate *)data;
> > - struct lto_file_decl_data *file_data = (struct lto_file_decl_data
> > *)node->value;
> > -
> > - lto_file_finalize (file_data, lw->file);
> > + lto_file_finalize (file_data, file);
> > if (cgraph_dump_file)
> > fprintf (cgraph_dump_file, "Creating file %s with sub id "
> > HOST_WIDE_INT_PRINT_HEX "\n",
> > file_data->file_name, file_data->id);
> > - file_data->next = *lw->file_data;
> > - *lw->file_data = file_data;
> > - (*lw->count)++;
> > + (*count)++;
> > return 0;
> > }
> >
> > @@ -1166,29 +1168,31 @@ lto_file_read (lto_file *file, FILE
> > *resolution_file, int *count)
> > struct lto_file_decl_data *file_data = NULL;
> > splay_tree file_ids;
> > htab_t section_hash_table;
> > - struct lwstate state;
> > -
> > - section_hash_table = lto_obj_build_section_table (file);
> > + struct lto_section_slot *section;
> > + struct file_data_list file_list;
> > + struct lto_section_list section_list;
> > +
> > + memset (§ion_list, 0, sizeof (struct lto_section_list));
> > + section_hash_table = lto_obj_build_section_table (file, §ion_list);
> >
> > /* Find all sub modules in the object and put their sections into new
> > hash
> > tables in a splay tree. */
> > file_ids = lto_splay_tree_new ();
> > - htab_traverse (section_hash_table, create_subid_section_table, file_ids);
> > -
> > + memset (&file_list, 0, sizeof (struct file_data_list));
> > + for (section = section_list.first; section != NULL; section =
> > section->next)
> > + create_subid_section_table (section, file_ids, &file_list);
> > +
> > /* Add resolutions to file ids */
> > lto_resolution_read (file_ids, resolution_file, file);
> >
> > - /* Finalize each lto file for each submodule in the merged object
> > - and create list for returning. */
> > - state.file = file;
> > - state.file_data = &file_data;
> > - state.count = count;
> > - splay_tree_foreach (file_ids, lto_create_files_from_ids, &state);
> > -
> > + /* Finalize each lto file for each submodule in the merged object */
> > + for (file_data = file_list.first; file_data != NULL; file_data =
> > file_data->next)
> > + lto_create_files_from_ids (file, file_data, count);
> > +
> > splay_tree_delete (file_ids);
> > htab_delete (section_hash_table);
> >
> > - return file_data;
> > + return file_list.first;
> > }
> >
> > #if HAVE_MMAP_FILE && HAVE_SYSCONF && defined _SC_PAGE_SIZE
> > @@ -2427,7 +2431,7 @@ lto_read_all_file_options (void)
> >
> > file_data = XCNEW (struct lto_file_decl_data);
> > file_data->file_name = file->filename;
> > - file_data->section_hash_table = lto_obj_build_section_table (file);
> > + file_data->section_hash_table = lto_obj_build_section_table (file,
> > NULL);
> >
> > lto_read_file_options (file_data);
> >
> > diff --git a/gcc/lto/lto.h b/gcc/lto/lto.h
> > index 8110ace..43fcca6 100644
> > --- a/gcc/lto/lto.h
> > +++ b/gcc/lto/lto.h
> > @@ -43,7 +43,8 @@ extern void lto_read_all_file_options (void);
> > /* In lto-elf.c or lto-coff.c */
> > extern lto_file *lto_obj_file_open (const char *filename, bool writable);
> > extern void lto_obj_file_close (lto_file *file);
> > -extern htab_t lto_obj_build_section_table (lto_file *file);
> > +struct lto_section_list;
> > +extern htab_t lto_obj_build_section_table (lto_file *file, struct
> > lto_section_list *list);
> > extern htab_t lto_obj_create_section_hash_table (void);
> > extern void lto_obj_begin_section (const char *name);
> > extern void lto_obj_append_data (const void *data, size_t len, void
> > *block);
> > @@ -58,6 +59,13 @@ struct lto_section_slot
> > const char *name;
> > intptr_t start;
> > size_t len;
> > + struct lto_section_slot *next;
> > +};
> > +
> > +/* A list of section slots */
> > +struct lto_section_list
> > +{
> > + struct lto_section_slot *first, *last;
> > };
> >
> > int64_t lto_parse_hex (const char *p);
>
>
--
Richard Guenther <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer
