From 78f28b89e8c7a2c9e262e2819f0da5629f226efc Mon Sep 17 00:00:00 2001 From: Nick Alcock Date: Wed, 27 Jan 2021 19:41:49 +0000 Subject: [PATCH] libctf: rip out dead code handling typedefs with no name There is special code in libctf to handle typedefs with no name, which the code calls "anonymous typedef nodes". These monsters are obviously not something C programs can include: the whole point of a ttypedef is to introduce a new name. Looking back at the history of DWARF in GCC, the only thing (outside C++ anonymous namespaces) which can generate a DW_TAG_typedef without a DW_AT_name is obsolete code to handle the long-removed -feliminate-dwarf2-dups option. Looking at OpenSolaris, typedef nodes with no name couldn't be generated by the DWARF->CTF converter at all (and its deduplicator barfed on them): the only reason for the existence of this code is a special case working around a peculiarity of stabs whereby types could sometimes be referenced before they were introduced. We don't need to carry code in libctf to handle special cases in an obsolete OpenSolaris converter (that yields a format that isn't readable by libctf anyway). So drop it. libctf/ChangeLog 2021-01-27 Nick Alcock * ctf-open.c (init_types): Rip out code to check anonymous typedef nodes. * ctf-create.c (ctf_add_reftype): Likewise. * ctf-lookup.c (refresh_pptrtab): Likewise. --- libctf/ChangeLog | 7 +++++++ libctf/ctf-create.c | 23 ++++++----------------- libctf/ctf-lookup.c | 24 ------------------------ libctf/ctf-open.c | 21 +-------------------- 4 files changed, 14 insertions(+), 61 deletions(-) diff --git a/libctf/ChangeLog b/libctf/ChangeLog index eaecb174be2..9b0dad92b07 100644 --- a/libctf/ChangeLog +++ b/libctf/ChangeLog @@ -1,3 +1,10 @@ +2021-01-27 Nick Alcock + + * ctf-open.c (init_types): Rip out code to check anonymous typedef + nodes. + * ctf-create.c (ctf_add_reftype): Likewise. + * ctf-lookup.c (refresh_pptrtab): Likewise. + 2021-01-27 Nick Alcock * ctf-impl.c (_libctf_nonnull_): Add parameters. diff --git a/libctf/ctf-create.c b/libctf/ctf-create.c index c5f79d167ad..cf473842846 100644 --- a/libctf/ctf-create.c +++ b/libctf/ctf-create.c @@ -1629,29 +1629,18 @@ ctf_add_reftype (ctf_dict_t *fp, uint32_t flag, ctf_id_t ref, uint32_t kind) if (kind != CTF_K_POINTER) return type; - /* If we are adding a pointer, update the ptrtab, both the directly pointed-to - type and (if an anonymous typedef node is being pointed at) the type that - points at too. Note that ctf_typemax is at this point one higher than we - want to check against, because it's just been incremented for the addition - of this type. The pptrtab is lazily-updated as needed, so is not touched - here. */ + /* If we are adding a pointer, update the ptrtab, pointing at this type from + the type it points to. Note that ctf_typemax is at this point one higher + than we want to check against, because it's just been incremented for the + addition of this type. The pptrtab is lazily-updated as needed, so is not + touched here. */ uint32_t type_idx = LCTF_TYPE_TO_INDEX (fp, type); uint32_t ref_idx = LCTF_TYPE_TO_INDEX (fp, ref); if (LCTF_TYPE_ISCHILD (fp, ref) == child && ref_idx < fp->ctf_typemax) - { - fp->ctf_ptrtab[ref_idx] = type_idx; - - ctf_id_t refref_idx = LCTF_TYPE_TO_INDEX (fp, dtd->dtd_data.ctt_type); - - if (tmp == fp - && (LCTF_INFO_KIND (fp, dtd->dtd_data.ctt_info) == CTF_K_TYPEDEF) - && strcmp (ctf_strptr (fp, dtd->dtd_data.ctt_name), "") == 0 - && refref_idx < fp->ctf_typemax) - fp->ctf_ptrtab[refref_idx] = type_idx; - } + fp->ctf_ptrtab[ref_idx] = type_idx; return type; } diff --git a/libctf/ctf-lookup.c b/libctf/ctf-lookup.c index 6d4e085838c..72f6a2a24c7 100644 --- a/libctf/ctf-lookup.c +++ b/libctf/ctf-lookup.c @@ -51,7 +51,6 @@ refresh_pptrtab (ctf_dict_t *fp, ctf_dict_t *pfp) { ctf_id_t type = LCTF_INDEX_TO_TYPE (fp, i, 1); ctf_id_t reffed_type; - int updated; if (ctf_type_kind (fp, type) != CTF_K_POINTER) continue; @@ -65,29 +64,6 @@ refresh_pptrtab (ctf_dict_t *fp, ctf_dict_t *pfp) /* Guard against references to invalid types. No need to consider the CTF dict corrupt in this case: this pointer just can't be a pointer to any type we know about. */ - if (idx <= pfp->ctf_typemax) - { - if (idx >= fp->ctf_pptrtab_len - && grow_pptrtab (fp, pfp->ctf_ptrtab_len) < 0) - return -1; /* errno is set for us. */ - - fp->ctf_pptrtab[idx] = i; - updated = 1; - } - } - if (!updated) - continue; - - /* If we updated the ptrtab entry for this type's referent, and it's an - anonymous typedef node, we also want to chase down its referent and - change that as well. */ - - if ((ctf_type_kind (fp, reffed_type) == CTF_K_TYPEDEF) - && strcmp (ctf_type_name_raw (fp, reffed_type), "") == 0) - { - uint32_t idx; - idx = LCTF_TYPE_TO_INDEX (pfp, ctf_type_reference (fp, reffed_type)); - if (idx <= pfp->ctf_typemax) { if (idx >= fp->ctf_pptrtab_len diff --git a/libctf/ctf-open.c b/libctf/ctf-open.c index a92668fd35f..67d9f84c361 100644 --- a/libctf/ctf-open.c +++ b/libctf/ctf-open.c @@ -683,7 +683,7 @@ init_types (ctf_dict_t *fp, ctf_header_t *cth) unsigned long pop[CTF_K_MAX + 1] = { 0 }; const ctf_type_t *tp; - uint32_t id, dst; + uint32_t id; uint32_t *xp; /* We determine whether the dict is a child or a parent based on the value of @@ -953,25 +953,6 @@ init_types (ctf_dict_t *fp, ctf_header_t *cth) ctf_dprintf ("%u base type names hashed\n", ctf_hash_size (fp->ctf_names.ctn_readonly)); - /* Make an additional pass through the pointer table to find pointers that - point to anonymous typedef nodes. If we find one, modify the pointer table - so that the pointer is also known to point to the node that is referenced - by the anonymous typedef node. */ - - for (id = 1; id <= fp->ctf_typemax; id++) - { - if ((dst = fp->ctf_ptrtab[id]) != 0) - { - tp = LCTF_INDEX_TO_TYPEPTR (fp, id); - - if (LCTF_INFO_KIND (fp, tp->ctt_info) == CTF_K_TYPEDEF - && strcmp (ctf_strptr (fp, tp->ctt_name), "") == 0 - && LCTF_TYPE_ISCHILD (fp, tp->ctt_type) == child - && LCTF_TYPE_TO_INDEX (fp, tp->ctt_type) <= fp->ctf_typemax) - fp->ctf_ptrtab[LCTF_TYPE_TO_INDEX (fp, tp->ctt_type)] = dst; - } - } - return 0; } -- 2.30.2