From 5f54462c6ab4665adec1f3e4591c095d63eae06a Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Fri, 5 Jun 2020 17:36:16 +0100 Subject: 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. --- libctf/ctf-link.c | 107 +++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 82 insertions(+), 25 deletions(-) (limited to 'libctf/ctf-link.c') diff --git a/libctf/ctf-link.c b/libctf/ctf-link.c index fa15c9b..3c96604 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); -- cgit v1.1