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/* C declarator syntax glue.
Copyright (C) 2019-2021 Free Software Foundation, Inc.
This file is part of libctf.
libctf is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING. If not see
<http://www.gnu.org/licenses/>. */
/* CTF Declaration Stack
In order to implement ctf_type_name(), we must convert a type graph back
into a C type declaration. Unfortunately, a type graph represents a storage
class ordering of the type whereas a type declaration must obey the C rules
for operator precedence, and the two orderings are frequently in conflict.
For example, consider these CTF type graphs and their C declarations:
CTF_K_POINTER -> CTF_K_FUNCTION -> CTF_K_INTEGER : int (*)()
CTF_K_POINTER -> CTF_K_ARRAY -> CTF_K_INTEGER : int (*)[]
In each case, parentheses are used to raise operator * to higher lexical
precedence, so the string form of the C declaration cannot be constructed by
walking the type graph links and forming the string from left to right.
The functions in this file build a set of stacks from the type graph nodes
corresponding to the C operator precedence levels in the appropriate order.
The code in ctf_type_name() can then iterate over the levels and nodes in
lexical precedence order and construct the final C declaration string. */
#include <ctf-impl.h>
#include <string.h>
void
ctf_decl_init (ctf_decl_t *cd)
{
int i;
memset (cd, 0, sizeof (ctf_decl_t));
for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++)
cd->cd_order[i] = CTF_PREC_BASE - 1;
cd->cd_qualp = CTF_PREC_BASE;
cd->cd_ordp = CTF_PREC_BASE;
}
void
ctf_decl_fini (ctf_decl_t *cd)
{
ctf_decl_node_t *cdp, *ndp;
int i;
for (i = CTF_PREC_BASE; i < CTF_PREC_MAX; i++)
{
for (cdp = ctf_list_next (&cd->cd_nodes[i]); cdp != NULL; cdp = ndp)
{
ndp = ctf_list_next (cdp);
free (cdp);
}
}
free (cd->cd_buf);
}
void
ctf_decl_push (ctf_decl_t *cd, ctf_dict_t *fp, ctf_id_t type)
{
ctf_decl_node_t *cdp;
ctf_decl_prec_t prec;
uint32_t kind, n = 1;
int is_qual = 0;
const ctf_type_t *tp;
ctf_arinfo_t ar;
if ((tp = ctf_lookup_by_id (&fp, type)) == NULL)
{
cd->cd_err = fp->ctf_errno;
return;
}
switch (kind = LCTF_INFO_KIND (fp, tp->ctt_info))
{
case CTF_K_ARRAY:
(void) ctf_array_info (fp, type, &ar);
ctf_decl_push (cd, fp, ar.ctr_contents);
n = ar.ctr_nelems;
prec = CTF_PREC_ARRAY;
break;
case CTF_K_TYPEDEF:
if (ctf_strptr (fp, tp->ctt_name)[0] == '\0')
{
ctf_decl_push (cd, fp, tp->ctt_type);
return;
}
prec = CTF_PREC_BASE;
break;
case CTF_K_FUNCTION:
ctf_decl_push (cd, fp, tp->ctt_type);
prec = CTF_PREC_FUNCTION;
break;
case CTF_K_POINTER:
ctf_decl_push (cd, fp, tp->ctt_type);
prec = CTF_PREC_POINTER;
break;
case CTF_K_SLICE:
/* Slices themselves have no print representation and should not appear in
the decl stack. */
ctf_decl_push (cd, fp, ctf_type_reference (fp, type));
return;
case CTF_K_VOLATILE:
case CTF_K_CONST:
case CTF_K_RESTRICT:
ctf_decl_push (cd, fp, tp->ctt_type);
prec = cd->cd_qualp;
is_qual++;
break;
default:
prec = CTF_PREC_BASE;
}
if ((cdp = malloc (sizeof (ctf_decl_node_t))) == NULL)
{
cd->cd_err = EAGAIN;
return;
}
cdp->cd_type = type;
cdp->cd_kind = kind;
cdp->cd_n = n;
if (ctf_list_next (&cd->cd_nodes[prec]) == NULL)
cd->cd_order[prec] = cd->cd_ordp++;
/* Reset cd_qualp to the highest precedence level that we've seen so
far that can be qualified (CTF_PREC_BASE or CTF_PREC_POINTER). */
if (prec > cd->cd_qualp && prec < CTF_PREC_ARRAY)
cd->cd_qualp = prec;
/* By convention qualifiers of base types precede the type specifier (e.g.
const int vs. int const) even though the two forms are equivalent. */
if (is_qual && prec == CTF_PREC_BASE)
ctf_list_prepend (&cd->cd_nodes[prec], cdp);
else
ctf_list_append (&cd->cd_nodes[prec], cdp);
}
_libctf_printflike_ (2, 3)
void ctf_decl_sprintf (ctf_decl_t *cd, const char *format, ...)
{
va_list ap;
char *str;
int n;
if (cd->cd_enomem)
return;
va_start (ap, format);
n = vasprintf (&str, format, ap);
va_end (ap);
if (n > 0)
{
char *newbuf;
if ((newbuf = ctf_str_append (cd->cd_buf, str)) != NULL)
cd->cd_buf = newbuf;
}
/* Sticky error condition. */
if (n < 0 || cd->cd_buf == NULL)
{
free (cd->cd_buf);
cd->cd_buf = NULL;
cd->cd_enomem = 1;
}
free (str);
}
char *ctf_decl_buf (ctf_decl_t *cd)
{
char *buf = cd->cd_buf;
cd->cd_buf = NULL;
return buf;
}
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