From 5f54462c6ab4665adec1f3e4591c095d63eae06a Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Fri, 5 Jun 2020 17:36:16 +0100 Subject: [PATCH] libctf, link: redo cu-mapping handling Now a bunch of stuff that doesn't apply to ld or any normal use of libctf, piled into one commit so that it's easier to ignore. The cu-mapping machinery associates incoming compilation unit names with outgoing names of CTF dictionaries that should correspond to them, for non-gdb CTF consumers that would like to group multiple TUs into a single child dict if conflicting types are found in it (the existing use case is one kernel module, one child CTF dict, even if the kernel module is composed of multiple CUs). The upcoming deduplicator needs to track not only the mapping from incoming CU name to outgoing dict name, but the inverse mapping from outgoing dict name to incoming CU name, so it can work over every CTF dict we might see in the output and link into it. So rejig the ctf-link machinery to do that. Simultaneously (because they are closely associated and were written at the same time), we add a new CTF_LINK_EMPTY_CU_MAPPINGS flag to ctf_link, which tells the ctf_link machinery to create empty child dicts for each outgoing CU mapping even if no CUs that correspond to it exist in the link. This is a bit (OK, quite a lot) of a waste of space, but some existing consumers require it. (Nobody else should use it.) Its value is not consecutive with existing CTF_LINK flag values because we're about to add more flags that are conceptually closer to the existing ones than this one is. include/ * ctf-api.h (CTF_LINK_EMPTY_CU_MAPPINGS): New. libctf/ * ctf-impl.h (ctf_file_t): Improve comments. : Split into... : ... this... : ... and this. * ctf-create.c (ctf_serialize): Adjust. * ctf-open.c (ctf_file_close): Likewise. * ctf-link.c (ctf_create_per_cu): Look things up in the in_cu_mapping instead of the cu_mapping. (ctf_link_add_cu_mapping): The deduplicating link will define what happens if many FROMs share a TO. (ctf_link_add_cu_mapping): Create in_cu_mapping and out_cu_mapping. Do not create ctf_link_outputs here any more, or create per-CU dicts here: they are already created when needed. (ctf_link_one_variable): Log a debug message if we skip a variable due to its type being concealed in a CU-mapped link. (This is probably too common a case to make into a warning.) (ctf_link): Create empty per-CU dicts if requested. --- include/ChangeLog | 4 ++ include/ctf-api.h | 6 ++- libctf/ChangeLog | 20 +++++++++ libctf/ctf-create.c | 6 ++- libctf/ctf-impl.h | 21 +++++++-- libctf/ctf-link.c | 107 +++++++++++++++++++++++++++++++++----------- libctf/ctf-open.c | 3 +- 7 files changed, 135 insertions(+), 32 deletions(-) diff --git a/include/ChangeLog b/include/ChangeLog index 6358ec6c78f..60d7b9fd115 100644 --- a/include/ChangeLog +++ b/include/ChangeLog @@ -1,3 +1,7 @@ +2020-07-22 Nick Alcock + + * ctf-api.h (CTF_LINK_EMPTY_CU_MAPPINGS): New. + 2020-07-22 Nick Alcock * ctf-api.h (ECTF_NEEDSBFD): New. diff --git a/include/ctf-api.h b/include/ctf-api.h index 7d3e1c8bfcd..700a2b1ef5d 100644 --- a/include/ctf-api.h +++ b/include/ctf-api.h @@ -78,7 +78,7 @@ typedef struct ctf_link_sym uint32_t st_value; } ctf_link_sym_t; -/* Indication of how to share types when linking. */ +/* Flags applying to this specific link. */ /* Share all types that are not in conflict. The default. */ #define CTF_LINK_SHARE_UNCONFLICTED 0x0 @@ -86,6 +86,10 @@ typedef struct ctf_link_sym /* Share only types that are used by multiple inputs. Not implemented yet. */ #define CTF_LINK_SHARE_DUPLICATED 0x1 +/* Create empty outputs for all registered CU mappings even if no types are + emitted into them. */ +#define CTF_LINK_EMPTY_CU_MAPPINGS 0x4 + /* Symbolic names for CTF sections. */ typedef enum ctf_sect_names diff --git a/libctf/ChangeLog b/libctf/ChangeLog index 848bc48b1e8..ba6664fa0ae 100644 --- a/libctf/ChangeLog +++ b/libctf/ChangeLog @@ -1,3 +1,23 @@ +2020-07-22 Nick Alcock + + * ctf-impl.h (ctf_file_t): Improve comments. + : Split into... + : ... this... + : ... and this. + * ctf-create.c (ctf_serialize): Adjust. + * ctf-open.c (ctf_file_close): Likewise. + * ctf-link.c (ctf_create_per_cu): Look things up in the + in_cu_mapping instead of the cu_mapping. + (ctf_link_add_cu_mapping): The deduplicating link will define + what happens if many FROMs share a TO. + (ctf_link_add_cu_mapping): Create in_cu_mapping and + out_cu_mapping. Do not create ctf_link_outputs here any more, or + create per-CU dicts here: they are already created when needed. + (ctf_link_one_variable): Log a debug message if we skip a + variable due to its type being concealed in a CU-mapped link. + (This is probably too common a case to make into a warning.) + (ctf_link): Create empty per-CU dicts if requested. + 2020-07-22 Nick Alcock * ctf-link.c (ctf_link_write): Close the fd. diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c index 85fd060262e..10c6bbf552e 100644 --- a/libctf/ctf-create.c +++ b/libctf/ctf-create.c @@ -538,7 +538,8 @@ ctf_serialize (ctf_file_t *fp) nfp->ctf_errs_warnings = fp->ctf_errs_warnings; nfp->ctf_str_prov_offset = fp->ctf_str_prov_offset; nfp->ctf_syn_ext_strtab = fp->ctf_syn_ext_strtab; - nfp->ctf_link_cu_mapping = fp->ctf_link_cu_mapping; + nfp->ctf_link_in_cu_mapping = fp->ctf_link_in_cu_mapping; + nfp->ctf_link_out_cu_mapping = fp->ctf_link_out_cu_mapping; nfp->ctf_link_type_mapping = fp->ctf_link_type_mapping; nfp->ctf_link_memb_name_changer = fp->ctf_link_memb_name_changer; nfp->ctf_link_memb_name_changer_arg = fp->ctf_link_memb_name_changer_arg; @@ -565,7 +566,8 @@ ctf_serialize (ctf_file_t *fp) fp->ctf_link_inputs = NULL; fp->ctf_link_outputs = NULL; fp->ctf_syn_ext_strtab = NULL; - fp->ctf_link_cu_mapping = NULL; + fp->ctf_link_in_cu_mapping = NULL; + fp->ctf_link_out_cu_mapping = NULL; fp->ctf_link_type_mapping = NULL; fp->ctf_parent_unreffed = 1; diff --git a/libctf/ctf-impl.h b/libctf/ctf-impl.h index cb7de23dbbb..46bceb49861 100644 --- a/libctf/ctf-impl.h +++ b/libctf/ctf-impl.h @@ -311,12 +311,27 @@ struct ctf_file ctf_list_t ctf_errs_warnings; /* CTF errors and warnings. */ ctf_dynhash_t *ctf_link_inputs; /* Inputs to this link. */ ctf_dynhash_t *ctf_link_outputs; /* Additional outputs from this link. */ - ctf_dynhash_t *ctf_link_type_mapping; /* Map input types to output types. */ - ctf_dynhash_t *ctf_link_cu_mapping; /* Map CU names to CTF dict names. */ - /* Allow the caller to Change the name of link archive members. */ + + /* Map input types to output types: populated in each output dict. + Key is a ctf_link_type_key_t: value is a type ID. Used by + nondeduplicating links and ad-hoc ctf_add_type calls only. */ + ctf_dynhash_t *ctf_link_type_mapping; + + /* Map input CU names to output CTF dict names: populated in the top-level + output dict. + + Key and value are dynamically-allocated strings. */ + ctf_dynhash_t *ctf_link_in_cu_mapping; + + /* Map output CTF dict names to input CU names: populated in the top-level + output dict. A hash of string to hash (set) of strings. Key and + individual value members are shared with ctf_link_in_cu_mapping. */ + ctf_dynhash_t *ctf_link_out_cu_mapping; + /* CTF linker flags. */ int ctf_link_flags; + /* Allow the caller to change the name of link archive members. */ ctf_link_memb_name_changer_f *ctf_link_memb_name_changer; void *ctf_link_memb_name_changer_arg; /* Argument for it. */ ctf_dynhash_t *ctf_add_processing; /* Types ctf_add_type is working on now. */ diff --git a/libctf/ctf-link.c b/libctf/ctf-link.c index fa15c9bf9bb..3c96604b36a 100644 --- a/libctf/ctf-link.c +++ b/libctf/ctf-link.c @@ -296,10 +296,12 @@ ctf_create_per_cu (ctf_file_t *fp, const char *filename, const char *cuname) dictionary name. We prefer the filename because this is easier for likely callers to determine. */ - if (fp->ctf_link_cu_mapping) + if (fp->ctf_link_in_cu_mapping) { - if (((ctf_name = ctf_dynhash_lookup (fp->ctf_link_cu_mapping, filename)) == NULL) && - ((ctf_name = ctf_dynhash_lookup (fp->ctf_link_cu_mapping, cuname)) == NULL)) + if (((ctf_name = ctf_dynhash_lookup (fp->ctf_link_in_cu_mapping, + filename)) == NULL) && + ((ctf_name = ctf_dynhash_lookup (fp->ctf_link_in_cu_mapping, + cuname)) == NULL)) ctf_name = filename; } @@ -339,10 +341,7 @@ ctf_create_per_cu (ctf_file_t *fp, const char *filename, const char *cuname) /* Add a mapping directing that the CU named FROM should have its conflicting/non-duplicate types (depending on link mode) go into a container - named TO. Many FROMs can share a TO: in this case, the effect on conflicting - types is not yet defined (but in time an auto-renaming algorithm will be - added: ugly, but there is really no right thing one can do in this - situation). + named TO. Many FROMs can share a TO. We forcibly add a container named TO in every case, even though it may well wind up empty, because clients that use this facility usually expect to find @@ -352,34 +351,63 @@ int ctf_link_add_cu_mapping (ctf_file_t *fp, const char *from, const char *to) { int err; - char *f, *t; + char *f = NULL, *t = NULL; + ctf_dynhash_t *one_out; + + if (fp->ctf_link_in_cu_mapping == NULL) + fp->ctf_link_in_cu_mapping = ctf_dynhash_create (ctf_hash_string, + ctf_hash_eq_string, free, + free); + if (fp->ctf_link_in_cu_mapping == NULL) + goto oom; - if (fp->ctf_link_cu_mapping == NULL) - fp->ctf_link_cu_mapping = ctf_dynhash_create (ctf_hash_string, - ctf_hash_eq_string, free, - free); - if (fp->ctf_link_cu_mapping == NULL) - return ctf_set_errno (fp, ENOMEM); + if (fp->ctf_link_out_cu_mapping == NULL) + fp->ctf_link_out_cu_mapping = ctf_dynhash_create (ctf_hash_string, + ctf_hash_eq_string, free, + (ctf_hash_free_fun) + ctf_dynhash_destroy); + if (fp->ctf_link_out_cu_mapping == NULL) + goto oom; - if (fp->ctf_link_outputs == NULL) - fp->ctf_link_outputs = ctf_dynhash_create (ctf_hash_string, - ctf_hash_eq_string, free, - (ctf_hash_free_fun) - ctf_file_close); + f = strdup (from); + t = strdup (to); + if (!f || !t) + goto oom; - if (fp->ctf_link_outputs == NULL) - return ctf_set_errno (fp, ENOMEM); + /* Track both in a list from FROM to TO and in a list from TO to a list of + FROM. The former is used to create TUs with the mapped-to name at need: + the latter is used in deduplicating links to pull in all input CUs + corresponding to a single output CU. */ + + if ((err = ctf_dynhash_insert (fp->ctf_link_in_cu_mapping, f, t)) < 0) + { + ctf_set_errno (fp, err); + goto oom_noerrno; + } + /* f and t are now owned by the in_cu_mapping: reallocate them. */ f = strdup (from); t = strdup (to); if (!f || !t) goto oom; - if (ctf_create_per_cu (fp, t, t) == NULL) - goto oom_noerrno; /* Errno is set for us. */ + if ((one_out = ctf_dynhash_lookup (fp->ctf_link_out_cu_mapping, t)) == NULL) + { + if ((one_out = ctf_dynhash_create (ctf_hash_string, ctf_hash_eq_string, + free, NULL)) == NULL) + goto oom; + if ((err = ctf_dynhash_insert (fp->ctf_link_out_cu_mapping, + t, one_out)) < 0) + { + ctf_dynhash_destroy (one_out); + ctf_set_errno (fp, err); + goto oom_noerrno; + } + } + else + free (t); - err = ctf_dynhash_insert (fp->ctf_link_cu_mapping, f, t); - if (err) + if (ctf_dynhash_insert (one_out, f, NULL) < 0) { ctf_set_errno (fp, err); goto oom_noerrno; @@ -777,6 +805,8 @@ int ctf_link (ctf_file_t *fp, int flags) { ctf_link_in_member_cb_arg_t arg; + ctf_next_t *i = NULL; + int err; memset (&arg, 0, sizeof (struct ctf_link_in_member_cb_arg)); arg.out_fp = fp; @@ -794,6 +824,33 @@ ctf_link (ctf_file_t *fp, int flags) if (fp->ctf_link_outputs == NULL) return ctf_set_errno (fp, ENOMEM); + /* Create empty CUs if requested. We do not currently claim that multiple + links in succession with CTF_LINK_EMPTY_CU_MAPPINGS set in some calls and + not set in others will do anything especially sensible. */ + + if (fp->ctf_link_out_cu_mapping && (flags & CTF_LINK_EMPTY_CU_MAPPINGS)) + { + void *v; + + while ((err = ctf_dynhash_next (fp->ctf_link_out_cu_mapping, &i, &v, + NULL)) == 0) + { + const char *to = (const char *) v; + if (ctf_create_per_cu (fp, to, to) == NULL) + { + ctf_next_destroy (i); + return -1; /* Errno is set for us. */ + } + } + if (err != ECTF_NEXT_END) + { + ctf_err_warn (fp, 1, "Iteration error creating empty CUs: %s", + ctf_errmsg (err)); + ctf_set_errno (fp, err); + return -1; + } + } + ctf_dynhash_iter (fp->ctf_link_inputs, ctf_link_one_input_archive, &arg); diff --git a/libctf/ctf-open.c b/libctf/ctf-open.c index 87bff2f122d..285e0e0ff71 100644 --- a/libctf/ctf-open.c +++ b/libctf/ctf-open.c @@ -1716,7 +1716,8 @@ ctf_file_close (ctf_file_t *fp) ctf_dynhash_destroy (fp->ctf_link_inputs); ctf_dynhash_destroy (fp->ctf_link_outputs); ctf_dynhash_destroy (fp->ctf_link_type_mapping); - ctf_dynhash_destroy (fp->ctf_link_cu_mapping); + ctf_dynhash_destroy (fp->ctf_link_in_cu_mapping); + ctf_dynhash_destroy (fp->ctf_link_out_cu_mapping); ctf_dynhash_destroy (fp->ctf_add_processing); for (err = ctf_list_next (&fp->ctf_errs_warnings); err != NULL; err = nerr) -- 2.30.2