/*
* dwarf-aux.c : libdw auxiliary interfaces
*
* This program 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 2 of the License, 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; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#include <stdbool.h>
#include "util.h"
#include "debug.h"
#include "dwarf-aux.h"
/**
* cu_find_realpath - Find the realpath of the target file
* @cu_die: A DIE(dwarf information entry) of CU(compilation Unit)
* @fname: The tail filename of the target file
*
* Find the real(long) path of @fname in @cu_die.
*/
const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
{
Dwarf_Files *files;
size_t nfiles, i;
const char *src = NULL;
int ret;
if (!fname)
return NULL;
ret = dwarf_getsrcfiles(cu_die, &files, &nfiles);
if (ret != 0)
return NULL;
for (i = 0; i < nfiles; i++) {
src = dwarf_filesrc(files, i, NULL, NULL);
if (strtailcmp(src, fname) == 0)
break;
}
if (i == nfiles)
return NULL;
return src;
}
/**
* cu_get_comp_dir - Get the path of compilation directory
* @cu_die: a CU DIE
*
* Get the path of compilation directory of given @cu_die.
* Since this depends on DW_AT_comp_dir, older gcc will not
* embedded it. In that case, this returns NULL.
*/
const char *cu_get_comp_dir(Dwarf_Die *cu_die)
{
Dwarf_Attribute attr;
if (dwarf_attr(cu_die, DW_AT_comp_dir, &attr) == NULL)
return NULL;
return dwarf_formstring(&attr);
}
/**
* cu_find_lineinfo - Get a line number and file name for given address
* @cu_die: a CU DIE
* @addr: An address
* @fname: a pointer which returns the file name string
* @lineno: a pointer which returns the line number
*
* Find a line number and file name for @addr in @cu_die.
*/
int cu_find_lineinfo(Dwarf_Die *cu_die, unsigned long addr,
const char **fname, int *lineno)
{
Dwarf_Line *line;
Dwarf_Addr laddr;
line = dwarf_getsrc_die(cu_die, (Dwarf_Addr)addr);
if (line && dwarf_lineaddr(line, &laddr) == 0 &&
addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) {
*fname = dwarf_linesrc(line, NULL, NULL);
if (!*fname)
/* line number is useless without filename */
*lineno = 0;
}
return *lineno ?: -ENOENT;
}
/**
* die_compare_name - Compare diename and tname
* @dw_die: a DIE
* @tname: a string of target name
*
* Compare the name of @dw_die and @tname. Return false if @dw_die has no name.
*/
bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
{
const char *name;
name = dwarf_diename(dw_die);
return name ? (strcmp(tname, name) == 0) : false;
}
/**
* die_get_call_lineno - Get callsite line number of inline-function instance
* @in_die: a DIE of an inlined function instance
*
* Get call-site line number of @in_die. This means from where the inline
* function is called.
*/
int die_get_call_lineno(Dwarf_Die *in_die)
{
Dwarf_Attribute attr;
Dwarf_Word ret;
if (!dwarf_attr(in_die, DW_AT_call_line, &attr))
return -ENOENT;
dwarf_formudata(&attr, &ret);
return (int)ret;
}
/**
* die_get_type - Get type DIE
* @vr_die: a DIE of a variable
* @die_mem: where to store a type DIE
*
* Get a DIE of the type of given variable (@vr_die), and store
* it to die_mem. Return NULL if fails to get a type DIE.
*/
Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
Dwarf_Attribute attr;
if (dwarf_attr_integrate(vr_die, DW_AT_type, &attr) &&
dwarf_formref_die(&attr, die_mem))
return die_mem;
else
return NULL;
}
/* Get a type die, but skip qualifiers */
static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
int tag;
do {
vr_die = die_get_type(vr_die, die_mem);
if (!vr_die)
break;
tag = dwarf_tag(vr_die);
} while (tag == DW_TAG_const_type ||
tag == DW_TAG_restrict_type ||
tag == DW_TAG_volatile_type ||
tag == DW_TAG_shared_type);
return vr_die;
}
/**
* die_get_real_type - Get a type die, but skip qualifiers and typedef
* @vr_die: a DIE of a variable
* @die_mem: where to store a type DIE
*
* Get a DIE of the type of given variable (@vr_die), and store
* it to die_mem. Return NULL if fails to get a type DIE.
* If the type is qualifiers (e.g. const) or typedef, this skips it
* and tries to find real type (structure or basic types, e.g. int).
*/
Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem)
{
do {
vr_die = __die_get_real_type(vr_die, die_mem);
} while (vr_die && dwarf_tag(vr_die) == DW_TAG_typedef);
return vr_die;
}
/* Get attribute and translate it as a udata */
static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name,
Dwarf_Word *result)
{
Dwarf_Attribute attr;
if (dwarf_attr(tp_die, attr_name, &attr) == NULL ||
dwarf_formudata(&attr, result) != 0)
return -ENOENT;
return 0;
}
/**
* die_is_signed_type - Check whether a type DIE is signed or not
* @tp_die: a DIE of a type
*
* Get the encoding of @tp_die and return true if the encoding
* is signed.
*/
bool die_is_signed_type(Dwarf_Die *tp_die)
{
Dwarf_Word ret;
if (die_get_attr_udata(tp_die, DW_AT_encoding, &ret))
return false;
return (ret == DW_ATE_signed_char || ret == DW_ATE_signed ||
ret == DW_ATE_signed_fixed);
}
/**
* die_get_data_member_location - Get the data-member offset
* @mb_die: a DIE of a member of a data structure
* @offs: The offset of the member in the data structure
*
* Get the offset of @mb_die in the data structure including @mb_die, and
* stores result offset to @offs. If any error occurs this returns errno.
*/
int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs)
{
Dwarf_Attribute attr;
Dwarf_Op *expr;
size_t nexpr;
int ret;
if (dwarf_attr(mb_die, DW_AT_data_member_location, &attr) == NULL)
return -ENOENT;
if (dwarf_formudata(&attr, offs) != 0) {
/* DW_AT_data_member_location should be DW_OP_plus_uconst */
ret = dwarf_getlocation(&attr, &expr, &nexpr);
if (ret < 0 || nexpr == 0)
return -ENOENT;
if (expr[0].atom != DW_OP_plus_uconst || nexpr != 1) {
pr_debug("Unable to get offset:Unexpected OP %x (%zd)\n",
expr[0].atom, nexpr);
return -ENOTSUP;
}
*offs = (Dwarf_Word)expr[0].number;
}
return 0;
}
/**
* die_find_child - Generic DIE search function in DIE tree
* @rt_die: a root DIE
* @callback: a callback function
* @data: a user data passed to the callback function
* @die_mem: a buffer for result DIE
*
* Trace DIE tree from @rt_die and call @callback for each child DIE.
* If @callback returns DIE_FIND_CB_END, this stores the DIE into
* @die_mem and returns it. If @callback returns DIE_FIND_CB_CONTINUE,
* this continues to trace the tree. Optionally, @callback can return
* DIE_FIND_CB_CHILD and DIE_FIND_CB_SIBLING, those means trace only
* the children and trace only the siblings respectively.
* Returns NULL if @callback can't find any appropriate DIE.
*/
Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
int (*callback)(Dwarf_Die *, void *),
void *data, Dwarf_Die *die_mem)
{
Dwarf_Die child_die;
int ret;
ret = dwarf_child(rt_die, die_mem);
if (ret != 0)
return NULL;
do {
ret = callback(die_mem, data);
if (ret == DIE_FIND_CB_END)
return die_mem;
if ((ret & DIE_FIND_CB_CHILD) &&
die_find_child(die_mem, callback, data, &child_die)) {
memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
return die_mem;
}
} while ((ret & DIE_FIND_CB_SIBLING) &&
dwarf_siblingof(die_mem, die_mem) == 0);
return NULL;
}
struct __addr_die_search_param {
Dwarf_Addr addr;
Dwarf_Die *die_mem;
};
/* die_find callback for non-inlined function search */
static int __die_search_func_cb(Dwarf_Die *fn_die, void *data)
{
struct __addr_die_search_param *ad = data;
if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
dwarf_haspc(fn_die, ad->addr)) {
memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
return DWARF_CB_ABORT;
}
return DWARF_CB_OK;
}
/**
* die_find_realfunc - Search a non-inlined function at given address
* @cu_die: a CU DIE which including @addr
* @addr: target address
* @die_mem: a buffer for result DIE
*
* Search a non-inlined function DIE which includes @addr. Stores the
* DIE to @die_mem and returns it if found. Returns NULl if failed.
*/
Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
Dwarf_Die *die_mem)
{
struct __addr_die_search_param ad;
ad.addr = addr;
ad.die_mem = die_mem;
/* dwarf_getscopes can't find subprogram. */
if (!dwarf_getfuncs(cu_die, __die_search_func_cb, &ad, 0))
return NULL;
else
return die_mem;
}
/* die_find callback for inline function search */
static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data)
{
Dwarf_Addr *addr = data;
if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
dwarf_haspc(die_mem, *addr))
return DIE_FIND_CB_END;
return DIE_FIND_CB_CONTINUE;
}
/**
* die_find_inlinefunc - Search an inlined function at given address
* @cu_die: a CU DIE which including @addr
* @addr: target address
* @die_mem: a buffer for result DIE
*
* Search an inlined function DIE which includes @addr. Stores the
* DIE to @die_mem and returns it if found. Returns NULl if failed.
* If several inlined functions are expanded recursively, this trace
* it and returns deepest one.
*/
Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
Dwarf_Die *die_mem)
{
Dwarf_Die tmp_die;
sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr, &tmp_die);
if (!sp_die)
return NULL;
/* Inlined function could be recursive. Trace it until fail */
while (sp_die) {
memcpy(die_mem, sp_die, sizeof(Dwarf_Die));
sp_die = die_find_child(sp_die, __die_find_inline_cb, &addr,
&tmp_die);
}
return die_mem;
}
/* Line walker internal parameters */
struct __line_walk_param {
const char *fname;
line_walk_callback_t callback;
void *data;
int retval;
};
static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data)
{
struct __line_walk_param *lw = data;
Dwarf_Addr addr;
int lineno;
if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
lineno = die_get_call_lineno(in_die);
if (lineno > 0 && dwarf_entrypc(in_die, &addr) == 0) {
lw->retval = lw->callback(lw->fname, lineno, addr,
lw->data);
if (lw->retval != 0)
return DIE_FIND_CB_END;
}
}
return DIE_FIND_CB_SIBLING;
}
/* Walk on lines of blocks included in given DIE */
static int __die_walk_funclines(Dwarf_Die *sp_die,
line_walk_callback_t callback, void *data)
{
struct __line_walk_param lw = {
.callback = callback,
.data = data,
.retval = 0,
};
Dwarf_Die die_mem;
Dwarf_Addr addr;
int lineno;
/* Handle function declaration line */
lw.fname = dwarf_decl_file(sp_die);
if (lw.fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
dwarf_entrypc(sp_die, &addr) == 0) {
lw.retval = callback(lw.fname, lineno, addr, data);
if (lw.retval != 0)
goto done;
}
die_find_child(sp_die, __die_walk_funclines_cb, &lw, &die_mem);
done:
return lw.retval;
}
static int __die_walk_culines_cb(Dwarf_Die *sp_die, void *data)
{
struct __line_walk_param *lw = data;
lw->retval = __die_walk_funclines(sp_die, lw->callback, lw->data);
if (lw->retval != 0)
return DWARF_CB_ABORT;
return DWARF_CB_OK;
}
/**
* die_walk_lines - Walk on lines inside given DIE
* @rt_die: a root DIE (CU, subprogram or inlined_subroutine)
* @callback: callback routine
* @data: user data
*
* Walk on all lines inside given @rt_die and call @callback on each line.
* If the @rt_die is a function, walk only on the lines inside the function,
* otherwise @rt_die must be a CU DIE.
* Note that this walks not only dwarf line list, but also function entries
* and inline call-site.
*/
int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data)
{
Dwarf_Lines *lines;
Dwarf_Line *line;
Dwarf_Addr addr;
const char *fname;
int lineno, ret = 0;
Dwarf_Die die_mem, *cu_die;
size_t nlines, i;
/* Get the CU die */
if (dwarf_tag(rt_die) != DW_TAG_compile_unit)
cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
else
cu_die = rt_die;
if (!cu_die) {
pr_debug2("Failed to get CU from given DIE.\n");
return -EINVAL;
}
/* Get lines list in the CU */
if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0) {
pr_debug2("Failed to get source lines on this CU.\n");
return -ENOENT;
}
pr_debug2("Get %zd lines from this CU\n", nlines);
/* Walk on the lines on lines list */
for (i = 0; i < nlines; i++) {
line = dwarf_onesrcline(lines, i);
if (line == NULL ||
dwarf_lineno(line, &lineno) != 0 ||
dwarf_lineaddr(line, &addr) != 0) {
pr_debug2("Failed to get line info. "
"Possible error in debuginfo.\n");
continue;
}
/* Filter lines based on address */
if (rt_die != cu_die)
/*
* Address filtering
* The line is included in given function, and
* no inline block includes it.
*/
if (!dwarf_haspc(rt_die, addr) ||
die_find_inlinefunc(rt_die, addr, &die_mem))
continue;
/* Get source line */
fname = dwarf_linesrc(line, NULL, NULL);
ret = callback(fname, lineno, addr, data);
if (ret != 0)
return ret;
}
/*
* Dwarf lines doesn't include function declarations and inlined
* subroutines. We have to check functions list or given function.
*/
if (rt_die != cu_die)
ret = __die_walk_funclines(rt_die, callback, data);
else {
struct __line_walk_param param = {
.callback = callback,
.data = data,
.retval = 0,
};
dwarf_getfuncs(cu_die, __die_walk_culines_cb, ¶m, 0);
ret = param.retval;
}
return ret;
}
struct __find_variable_param {
const char *name;
Dwarf_Addr addr;
};
static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data)
{
struct __find_variable_param *fvp = data;
int tag;
tag = dwarf_tag(die_mem);
if ((tag == DW_TAG_formal_parameter ||
tag == DW_TAG_variable) &&
die_compare_name(die_mem, fvp->name))
return DIE_FIND_CB_END;
if (dwarf_haspc(die_mem, fvp->addr))
return DIE_FIND_CB_CONTINUE;
else
return DIE_FIND_CB_SIBLING;
}
/**
* die_find_variable_at - Find a given name variable at given address
* @sp_die: a function DIE
* @name: variable name
* @addr: address
* @die_mem: a buffer for result DIE
*
* Find a variable DIE called @name at @addr in @sp_die.
*/
Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
Dwarf_Addr addr, Dwarf_Die *die_mem)
{
struct __find_variable_param fvp = { .name = name, .addr = addr};
return die_find_child(sp_die, __die_find_variable_cb, (void *)&fvp,
die_mem);
}
static int __die_find_member_cb(Dwarf_Die *die_mem, void *data)
{
const char *name = data;
if ((dwarf_tag(die_mem) == DW_TAG_member) &&
die_compare_name(die_mem, name))
return DIE_FIND_CB_END;
return DIE_FIND_CB_SIBLING;
}
/**
* die_find_member - Find a given name member in a data structure
* @st_die: a data structure type DIE
* @name: member name
* @die_mem: a buffer for result DIE
*
* Find a member DIE called @name in @st_die.
*/
Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
Dwarf_Die *die_mem)
{
return die_find_child(st_die, __die_find_member_cb, (void *)name,
die_mem);
}
/**
* die_get_typename - Get the name of given variable DIE
* @vr_die: a variable DIE
* @buf: a buffer for result type name
* @len: a max-length of @buf
*
* Get the name of @vr_die and stores it to @buf. Return the actual length
* of type name if succeeded. Return -E2BIG if @len is not enough long, and
* Return -ENOENT if failed to find type name.
* Note that the result will stores typedef name if possible, and stores
* "*(function_type)" if the type is a function pointer.
*/
int die_get_typename(Dwarf_Die *vr_die, char *buf, int len)
{
Dwarf_Die type;
int tag, ret, ret2;
const char *tmp = "";
if (__die_get_real_type(vr_die, &type) == NULL)
return -ENOENT;
tag = dwarf_tag(&type);
if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
tmp = "*";
else if (tag == DW_TAG_subroutine_type) {
/* Function pointer */
ret = snprintf(buf, len, "(function_type)");
return (ret >= len) ? -E2BIG : ret;
} else {
if (!dwarf_diename(&type))
return -ENOENT;
if (tag == DW_TAG_union_type)
tmp = "union ";
else if (tag == DW_TAG_structure_type)
tmp = "struct ";
/* Write a base name */
ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type));
return (ret >= len) ? -E2BIG : ret;
}
ret = die_get_typename(&type, buf, len);
if (ret > 0) {
ret2 = snprintf(buf + ret, len - ret, "%s", tmp);
ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
}
return ret;
}
/**
* die_get_varname - Get the name and type of given variable DIE
* @vr_die: a variable DIE
* @buf: a buffer for type and variable name
* @len: the max-length of @buf
*
* Get the name and type of @vr_die and stores it in @buf as "type\tname".
*/
int die_get_varname(Dwarf_Die *vr_die, char *buf, int len)
{
int ret, ret2;
ret = die_get_typename(vr_die, buf, len);
if (ret < 0) {
pr_debug("Failed to get type, make it unknown.\n");
ret = snprintf(buf, len, "(unknown_type)");
}
if (ret > 0) {
ret2 = snprintf(buf + ret, len - ret, "\t%s",
dwarf_diename(vr_die));
ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret;
}
return ret;
}
