// SPDX-License-Identifier: GPL-2.0-or-later
/*
* dwarf-aux.c : libdw auxiliary interfaces
*/
#include <errno.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdlib.h>
#include "debug.h"
#include "dwarf-aux.h"
#include "strbuf.h"
#include "string2.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);
}
/* Unlike dwarf_getsrc_die(), cu_getsrc_die() only returns statement line */
static Dwarf_Line *cu_getsrc_die(Dwarf_Die *cu_die, Dwarf_Addr addr)
{
Dwarf_Addr laddr;
Dwarf_Lines *lines;
Dwarf_Line *line;
size_t nlines, l, u, n;
bool flag;
if (dwarf_getsrclines(cu_die, &lines, &nlines) != 0 ||
nlines == 0)
return NULL;
/* Lines are sorted by address, use binary search */
l = 0; u = nlines - 1;
while (l < u) {
n = u - (u - l) / 2;
line = dwarf_onesrcline(lines, n);
if (!line || dwarf_lineaddr(line, &laddr) != 0)
return NULL;
if (addr < laddr)
u = n - 1;
else
l = n;
}
/* Going backward to find the lowest line */
do {
line = dwarf_onesrcline(lines, --l);
if (!line || dwarf_lineaddr(line, &laddr) != 0)
return NULL;
} while (laddr == addr);
l++;
/* Going forward to find the statement line */
do {
line = dwarf_onesrcline(lines, l++);
if (!line || dwarf_lineaddr(line, &laddr) != 0 ||
dwarf_linebeginstatement(line, &flag) != 0)
return NULL;
if (laddr > addr)
return NULL;
} while (!flag);
return line;
}
/**
* 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, Dwarf_Addr addr,
const char **fname, int *lineno)
{
Dwarf_Line *line;
Dwarf_Die die_mem;
Dwarf_Addr faddr;
if (die_find_realfunc(cu_die, addr, &die_mem)
&& die_entrypc(&die_mem, &faddr) == 0 &&
faddr == addr) {
*fname = die_get_decl_file(&die_mem);
dwarf_decl_line(&die_mem, lineno);
goto out;
}
line = cu_getsrc_die(cu_die, addr);
if (line && dwarf_lineno(line, lineno) == 0) {
*fname = dwarf_linesrc(line, NULL, NULL);
if (!*fname)
/* line number is useless without filename */
*lineno = 0;
}
out:
return (*lineno && *fname) ? *lineno : -ENOENT;
}
static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data);
/**
* cu_walk_functions_at - Walk on function DIEs at given address
* @cu_die: A CU DIE
* @addr: An address
* @callback: A callback which called with found DIEs
* @data: A user data
*
* Walk on function DIEs at given @addr in @cu_die. Passed DIEs
* should be subprogram or inlined-subroutines.
*/
int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
int (*callback)(Dwarf_Die *, void *), void *data)
{
Dwarf_Die die_mem;
Dwarf_Die *sc_die;
int ret = -ENOENT;
/* Inlined function could be recursive. Trace it until fail */
for (sc_die = die_find_realfunc(cu_die, addr, &die_mem);
sc_die != NULL;
sc_die = die_find_child(sc_die, __die_find_inline_cb, &addr,
&die_mem)) {
ret = callback(sc_die, data);
if (ret)
break;
}
return ret;
}
/**
* die_get_linkage_name - Get the linkage name of the object
* @dw_die: A DIE of the object
*
* Get the linkage name attribute of given @dw_die.
* For C++ binary, the linkage name will be the mangled symbol.
*/
const char *die_get_linkage_name(Dwarf_Die *dw_die)
{
Dwarf_Attribute attr;
if (dwarf_attr_integrate(dw_die, DW_AT_linkage_name, &attr) == NULL)
return NULL;
return dwarf_formstring(&attr);
}
/**
* 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_match_name - Match diename/linkage name and glob
* @dw_die: a DIE
* @glob: a string of target glob pattern
*
* Glob matching the name of @dw_die and @glob. Return false if matching fail.
* This also match linkage name.
*/
bool die_match_name(Dwarf_Die *dw_die, const char *glob)
{
const char *name;
name = dwarf_diename(dw_die);
if (name && strglobmatch(name, glob))
return true;
/* fall back to check linkage name */
name = die_get_linkage_name(dw_die);
if (name && strglobmatch(name, glob))
return true;
return 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_integrate(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_is_func_def - Ensure that this DIE is a subprogram and definition
* @dw_die: a DIE
*
* Ensure that this DIE is a subprogram and NOT a declaration. This
* returns true if @dw_die is a function definition.
**/
bool die_is_func_def(Dwarf_Die *dw_die)
{
Dwarf_Attribute attr;
Dwarf_Addr addr = 0;
if (dwarf_tag(dw_die) != DW_TAG_subprogram)
return false;
if (dwarf_attr(dw_die, DW_AT_declaration, &attr))
return false;
/*
* DW_AT_declaration can be lost from function declaration
* by gcc's bug #97060.
* So we need to check this subprogram DIE has DW_AT_inline
* or an entry address.
*/
if (!dwarf_attr(dw_die, DW_AT_inline, &attr) &&
die_entrypc(dw_die, &addr) < 0)
return false;
return true;
}
/**
* die_entrypc - Returns entry PC (the lowest address) of a DIE
* @dw_die: a DIE
* @addr: where to store entry PC
*
* Since dwarf_entrypc() does not return entry PC if the DIE has only address
* range, we have to use this to retrieve the lowest address from the address
* range attribute.
*/
int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
{
Dwarf_Addr base, end;
Dwarf_Attribute attr;
if (!addr)
return -EINVAL;
if (dwarf_entrypc(dw_die, addr) == 0)
return 0;
/*
* Since the dwarf_ranges() will return 0 if there is no
* DW_AT_ranges attribute, we should check it first.
*/
if (!dwarf_attr(dw_die, DW_AT_ranges, &attr))
return -ENOENT;
return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
}
/**
* die_is_func_instance - Ensure that this DIE is an instance of a subprogram
* @dw_die: a DIE
*
* Ensure that this DIE is an instance (which has an entry address).
* This returns true if @dw_die is a function instance. If not, the @dw_die
* must be a prototype. You can use die_walk_instances() to find actual
* instances.
**/
bool die_is_func_instance(Dwarf_Die *dw_die)
{
Dwarf_Addr tmp;
Dwarf_Attribute attr_mem;
int tag = dwarf_tag(dw_die);
if (tag != DW_TAG_subprogram &&
tag != DW_TAG_inlined_subroutine)
return false;
return dwarf_entrypc(dw_die, &tmp) == 0 ||
dwarf_attr(dw_die, DW_AT_ranges, &attr_mem) != NULL;
}
/**
* 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;
}
/* Get the call file index number in CU DIE */
static int die_get_call_fileno(Dwarf_Die *in_die)
{
Dwarf_Word idx;
if (die_get_attr_udata(in_die, DW_AT_call_file, &idx) == 0)
return (int)idx;
else
return -ENOENT;
}
/* Get the declared file index number in CU DIE */
static int die_get_decl_fileno(Dwarf_Die *pdie)
{
Dwarf_Word idx;
if (die_get_attr_udata(pdie, DW_AT_decl_file, &idx) == 0)
return (int)idx;
else
return -ENOENT;
}
/* Return the file name by index */
static const char *die_get_file_name(Dwarf_Die *dw_die, int idx)
{
Dwarf_Die cu_die;
Dwarf_Files *files;
Dwarf_Attribute attr_mem;
if (idx < 0 || !dwarf_attr_integrate(dw_die, DW_AT_decl_file, &attr_mem) ||
!dwarf_cu_die(attr_mem.cu, &cu_die, NULL, NULL, NULL, NULL, NULL, NULL) ||
dwarf_getsrcfiles(&cu_die, &files, NULL) != 0)
return NULL;
return dwarf_filesrc(files, idx, NULL, NULL);
}
/**
* die_get_call_file - Get callsite file name of inlined function instance
* @in_die: a DIE of an inlined function instance
*
* Get call-site file name of @in_die. This means from which file the inline
* function is called.
*/
const char *die_get_call_file(Dwarf_Die *in_die)
{
return die_get_file_name(in_die, die_get_call_fileno(in_die));
}
/**
* die_get_decl_file - Find the declared file name of this DIE
* @dw_die: a DIE for something declared.
*
* Get declared file name of @dw_die.
* NOTE: Since some version of clang DWARF5 implementation incorrectly uses
* file index 0 for DW_AT_decl_file, die_get_decl_file() will return NULL for
* such cases. Use this function instead.
*/
const char *die_get_decl_file(Dwarf_Die *dw_die)
{
return die_get_file_name(dw_die, die_get_decl_fileno(dw_die));
}
/**
* 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;
};
static int __die_search_func_tail_cb(Dwarf_Die *fn_die, void *data)
{
struct __addr_die_search_param *ad = data;
Dwarf_Addr addr = 0;
if (dwarf_tag(fn_die) == DW_TAG_subprogram &&
!dwarf_highpc(fn_die, &addr) &&
addr == ad->addr) {
memcpy(ad->die_mem, fn_die, sizeof(Dwarf_Die));
return DWARF_CB_ABORT;
}
return DWARF_CB_OK;
}
/**
* die_find_tailfunc - Search for a non-inlined function with tail call at
* given address
* @cu_die: a CU DIE which including @addr
* @addr: target address
* @die_mem: a buffer for result DIE
*
* Search for a non-inlined function DIE with tail call at @addr. Stores the
* DIE to @die_mem and returns it if found. Returns NULL if failed.
*/
Dwarf_Die *die_find_tailfunc(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_tail_cb, &ad, 0))
return NULL;
else
return 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;
/*
* Since a declaration entry doesn't has given pc, this always returns
* function definition entry.
*/
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_top_inlinefunc - Search the top inlined function at given address
* @sp_die: a subprogram 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.
* Even if several inlined functions are expanded recursively, this
* doesn't trace it down, and returns the topmost one.
*/
Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
Dwarf_Die *die_mem)
{
return die_find_child(sp_die, __die_find_inline_cb, &addr, die_mem);
}
/**
* die_find_inlinefunc - Search an inlined function at given address
* @sp_die: a subprogram 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 down 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;
}
struct __instance_walk_param {
void *addr;
int (*callback)(Dwarf_Die *, void *);
void *data;
int retval;
};
static int __die_walk_instances_cb(Dwarf_Die *inst, void *data)
{
struct __instance_walk_param *iwp = data;
Dwarf_Attribute attr_mem;
Dwarf_Die origin_mem;
Dwarf_Attribute *attr;
Dwarf_Die *origin;
int tmp;
if (!die_is_func_instance(inst))
return DIE_FIND_CB_CONTINUE;
attr = dwarf_attr(inst, DW_AT_abstract_origin, &attr_mem);
if (attr == NULL)
return DIE_FIND_CB_CONTINUE;
origin = dwarf_formref_die(attr, &origin_mem);
if (origin == NULL || origin->addr != iwp->addr)
return DIE_FIND_CB_CONTINUE;
/* Ignore redundant instances */
if (dwarf_tag(inst) == DW_TAG_inlined_subroutine) {
dwarf_decl_line(origin, &tmp);
if (die_get_call_lineno(inst) == tmp) {
tmp = die_get_decl_fileno(origin);
if (die_get_call_fileno(inst) == tmp)
return DIE_FIND_CB_CONTINUE;
}
}
iwp->retval = iwp->callback(inst, iwp->data);
return (iwp->retval) ? DIE_FIND_CB_END : DIE_FIND_CB_CONTINUE;
}
/**
* die_walk_instances - Walk on instances of given DIE
* @or_die: an abstract original DIE
* @callback: a callback function which is called with instance DIE
* @data: user data
*
* Walk on the instances of give @in_die. @in_die must be an inlined function
* declaration. This returns the return value of @callback if it returns
* non-zero value, or -ENOENT if there is no instance.
*/
int die_walk_instances(Dwarf_Die *or_die, int (*callback)(Dwarf_Die *, void *),
void *data)
{
Dwarf_Die cu_die;
Dwarf_Die die_mem;
struct __instance_walk_param iwp = {
.addr = or_die->addr,
.callback = callback,
.data = data,
.retval = -ENOENT,
};
if (dwarf_diecu(or_die, &cu_die, NULL, NULL) == NULL)
return -ENOENT;
die_find_child(&cu_die, __die_walk_instances_cb, &iwp, &die_mem);
return iwp.retval;
}
/* Line walker internal parameters */
struct __line_walk_param {
bool recursive;
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 = 0;
const char *fname;
int lineno;
if (dwarf_tag(in_die) == DW_TAG_inlined_subroutine) {
fname = die_get_call_file(in_die);
lineno = die_get_call_lineno(in_die);
if (fname && lineno > 0 && die_entrypc(in_die, &addr) == 0) {
lw->retval = lw->callback(fname, lineno, addr, lw->data);
if (lw->retval != 0)
return DIE_FIND_CB_END;
}
if (!lw->recursive)
return DIE_FIND_CB_SIBLING;
}
if (addr) {
fname = die_get_decl_file(in_die);
if (fname && dwarf_decl_line(in_die, &lineno) == 0) {
lw->retval = lw->callback(fname, lineno, addr, lw->data);
if (lw->retval != 0)
return DIE_FIND_CB_END;
}
}
/* Continue to search nested inlined function call-sites */
return DIE_FIND_CB_CONTINUE;
}
/* Walk on lines of blocks included in given DIE */
static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
line_walk_callback_t callback, void *data)
{
struct __line_walk_param lw = {
.recursive = recursive,
.callback = callback,
.data = data,
.retval = 0,
};
Dwarf_Die die_mem;
Dwarf_Addr addr;
const char *fname;
int lineno;
/* Handle function declaration line */
fname = die_get_decl_file(sp_die);
if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
die_entrypc(sp_die, &addr) == 0) {
lw.retval = callback(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;
/*
* Since inlined function can include another inlined function in
* the same file, we need to walk in it recursively.
*/
lw->retval = __die_walk_funclines(sp_die, true, 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, *decf = NULL, *inf = NULL;
int lineno, ret = 0;
int decl = 0, inl;
Dwarf_Die die_mem, *cu_die;
size_t nlines, i;
bool flag;
/* Get the CU die */
if (dwarf_tag(rt_die) != DW_TAG_compile_unit) {
cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL);
dwarf_decl_line(rt_die, &decl);
decf = die_get_decl_file(rt_die);
if (!decf) {
pr_debug2("Failed to get the declared file name of %s\n",
dwarf_diename(rt_die));
return -EINVAL;
}
} 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;
}
/* Skip end-of-sequence */
if (dwarf_lineendsequence(line, &flag) != 0 || flag)
continue;
/* Skip Non statement line-info */
if (dwarf_linebeginstatement(line, &flag) != 0 || !flag)
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))
continue;
if (die_find_inlinefunc(rt_die, addr, &die_mem)) {
/* Call-site check */
inf = die_get_call_file(&die_mem);
if ((inf && !strcmp(inf, decf)) &&
die_get_call_lineno(&die_mem) == lineno)
goto found;
dwarf_decl_line(&die_mem, &inl);
if (inl != decl ||
decf != die_get_decl_file(&die_mem))
continue;
}
}
found:
/* 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)
/*
* Don't need walk inlined functions recursively, because
* inner inlined functions don't have the lines of the
* specified function.
*/
ret = __die_walk_funclines(rt_die, false, 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;
Dwarf_Attribute attr;
int tag;
tag = dwarf_tag(die_mem);
if ((tag == DW_TAG_formal_parameter ||
tag == DW_TAG_variable) &&
die_compare_name(die_mem, fvp->name) &&
/*
* Does the DIE have location information or const value
* or external instance?
*/
(dwarf_attr(die_mem, DW_AT_external, &attr) ||
dwarf_attr(die_mem, DW_AT_location, &attr) ||
dwarf_attr(die_mem, DW_AT_const_value, &attr)))
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) {
if (die_compare_name(die_mem, name))
return DIE_FIND_CB_END;
else if (!dwarf_diename(die_mem)) { /* Unnamed structure */
Dwarf_Die type_die, tmp_die;
if (die_get_type(die_mem, &type_die) &&
die_find_member(&type_die, name, &tmp_die))
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 strbuf for result type name
*
* Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
* 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, struct strbuf *buf)
{
Dwarf_Die type;
int tag, ret;
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 */
return strbuf_add(buf, "(function_type)", 15);
} else {
const char *name = dwarf_diename(&type);
if (tag == DW_TAG_union_type)
tmp = "union ";
else if (tag == DW_TAG_structure_type)
tmp = "struct ";
else if (tag == DW_TAG_enumeration_type)
tmp = "enum ";
else if (name == NULL)
return -ENOENT;
/* Write a base name */
return strbuf_addf(buf, "%s%s", tmp, name ?: "");
}
ret = die_get_typename(&type, buf);
return ret ? ret : strbuf_addstr(buf, tmp);
}
/**
* die_get_varname - Get the name and type of given variable DIE
* @vr_die: a variable DIE
* @buf: a strbuf for type and variable name
*
* Get the name and type of @vr_die and stores it in @buf as "type\tname".
*/
int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
{
int ret;
ret = die_get_typename(vr_die, buf);
if (ret < 0) {
pr_debug("Failed to get type, make it unknown.\n");
ret = strbuf_add(buf, "(unknown_type)", 14);
}
return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die));
}
#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT
/**
* die_get_var_innermost_scope - Get innermost scope range of given variable DIE
* @sp_die: a subprogram DIE
* @vr_die: a variable DIE
* @buf: a strbuf for variable byte offset range
*
* Get the innermost scope range of @vr_die and stores it in @buf as
* "@<function_name+[NN-NN,NN-NN]>".
*/
static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
struct strbuf *buf)
{
Dwarf_Die *scopes;
int count;
size_t offset = 0;
Dwarf_Addr base;
Dwarf_Addr start, end;
Dwarf_Addr entry;
int ret;
bool first = true;
const char *name;
ret = die_entrypc(sp_die, &entry);
if (ret)
return ret;
name = dwarf_diename(sp_die);
if (!name)
return -ENOENT;
count = dwarf_getscopes_die(vr_die, &scopes);
/* (*SCOPES)[1] is the DIE for the scope containing that scope */
if (count <= 1) {
ret = -EINVAL;
goto out;
}
while ((offset = dwarf_ranges(&scopes[1], offset, &base,
&start, &end)) > 0) {
start -= entry;
end -= entry;
if (first) {
ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
name, start, end);
first = false;
} else {
ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
start, end);
}
if (ret < 0)
goto out;
}
if (!first)
ret = strbuf_add(buf, "]>", 2);
out:
free(scopes);
return ret;
}
/**
* die_get_var_range - Get byte offset range of given variable DIE
* @sp_die: a subprogram DIE
* @vr_die: a variable DIE
* @buf: a strbuf for type and variable name and byte offset range
*
* Get the byte offset range of @vr_die and stores it in @buf as
* "@<function_name+[NN-NN,NN-NN]>".
*/
int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
{
int ret = 0;
Dwarf_Addr base;
Dwarf_Addr start, end;
Dwarf_Addr entry;
Dwarf_Op *op;
size_t nops;
size_t offset = 0;
Dwarf_Attribute attr;
bool first = true;
const char *name;
ret = die_entrypc(sp_die, &entry);
if (ret)
return ret;
name = dwarf_diename(sp_die);
if (!name)
return -ENOENT;
if (dwarf_attr(vr_die, DW_AT_location, &attr) == NULL)
return -EINVAL;
while ((offset = dwarf_getlocations(&attr, offset, &base,
&start, &end, &op, &nops)) > 0) {
if (start == 0) {
/* Single Location Descriptions */
ret = die_get_var_innermost_scope(sp_die, vr_die, buf);
goto out;
}
/* Location Lists */
start -= entry;
end -= entry;
if (first) {
ret = strbuf_addf(buf, "@<%s+[%" PRIu64 "-%" PRIu64,
name, start, end);
first = false;
} else {
ret = strbuf_addf(buf, ",%" PRIu64 "-%" PRIu64,
start, end);
}
if (ret < 0)
goto out;
}
if (!first)
ret = strbuf_add(buf, "]>", 2);
out:
return ret;
}
#else
int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
Dwarf_Die *vr_die __maybe_unused,
struct strbuf *buf __maybe_unused)
{
return -ENOTSUP;
}
#endif
/*
* die_has_loclist - Check if DW_AT_location of @vr_die is a location list
* @vr_die: a variable DIE
*/
static bool die_has_loclist(Dwarf_Die *vr_die)
{
Dwarf_Attribute loc;
int tag = dwarf_tag(vr_die);
if (tag != DW_TAG_formal_parameter &&
tag != DW_TAG_variable)
return false;
return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
dwarf_whatform(&loc) == DW_FORM_sec_offset);
}
/*
* die_is_optimized_target - Check if target program is compiled with
* optimization
* @cu_die: a CU DIE
*
* For any object in given CU whose DW_AT_location is a location list,
* target program is compiled with optimization. This is applicable to
* clang as well.
*/
bool die_is_optimized_target(Dwarf_Die *cu_die)
{
Dwarf_Die tmp_die;
if (die_has_loclist(cu_die))
return true;
if (!dwarf_child(cu_die, &tmp_die) &&
die_is_optimized_target(&tmp_die))
return true;
if (!dwarf_siblingof(cu_die, &tmp_die) &&
die_is_optimized_target(&tmp_die))
return true;
return false;
}
/*
* die_search_idx - Search index of given line address
* @lines: Line records of single CU
* @nr_lines: Number of @lines
* @addr: address we are looking for
* @idx: index to be set by this function (return value)
*
* Search for @addr by looping over every lines of CU. If address
* matches, set index of that line in @idx. Note that single source
* line can have multiple line records. i.e. single source line can
* have multiple index.
*/
static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
Dwarf_Addr addr, unsigned long *idx)
{
unsigned long i;
Dwarf_Addr tmp;
for (i = 0; i < nr_lines; i++) {
if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
return false;
if (tmp == addr) {
*idx = i;
return true;
}
}
return false;
}
/*
* die_get_postprologue_addr - Search next address after function prologue
* @entrypc_idx: entrypc index
* @lines: Line records of single CU
* @nr_lines: Number of @lines
* @hignpc: high PC address of function
* @postprologue_addr: Next address after function prologue (return value)
*
* Look for prologue-end marker. If there is no explicit marker, return
* address of next line record or next source line.
*/
static bool die_get_postprologue_addr(unsigned long entrypc_idx,
Dwarf_Lines *lines,
unsigned long nr_lines,
Dwarf_Addr highpc,
Dwarf_Addr *postprologue_addr)
{
unsigned long i;
int entrypc_lno, lno;
Dwarf_Line *line;
Dwarf_Addr addr;
bool p_end;
/* entrypc_lno is actual source line number */
line = dwarf_onesrcline(lines, entrypc_idx);
if (dwarf_lineno(line, &entrypc_lno))
return false;
for (i = entrypc_idx; i < nr_lines; i++) {
line = dwarf_onesrcline(lines, i);
if (dwarf_lineaddr(line, &addr) ||
dwarf_lineno(line, &lno) ||
dwarf_lineprologueend(line, &p_end))
return false;
/* highpc is exclusive. [entrypc,highpc) */
if (addr >= highpc)
break;
/* clang supports prologue-end marker */
if (p_end)
break;
/* Actual next line in source */
if (lno != entrypc_lno)
break;
/*
* Single source line can have multiple line records.
* For Example,
* void foo() { printf("hello\n"); }
* contains two line records. One points to declaration and
* other points to printf() line. Variable 'lno' won't get
* incremented in this case but 'i' will.
*/
if (i != entrypc_idx)
break;
}
dwarf_lineaddr(line, postprologue_addr);
if (*postprologue_addr >= highpc)
dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
postprologue_addr);
return true;
}
/*
* die_skip_prologue - Use next address after prologue as probe location
* @sp_die: a subprogram DIE
* @cu_die: a CU DIE
* @entrypc: entrypc of the function
*
* Function prologue prepares stack and registers before executing function
* logic. When target program is compiled without optimization, function
* parameter information is only valid after prologue. When we probe entrypc
* of the function, and try to record function parameter, it contains
* garbage value.
*/
void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
Dwarf_Addr *entrypc)
{
size_t nr_lines = 0;
unsigned long entrypc_idx = 0;
Dwarf_Lines *lines = NULL;
Dwarf_Addr postprologue_addr;
Dwarf_Addr highpc;
if (dwarf_highpc(sp_die, &highpc))
return;
if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
return;
if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
return;
if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
highpc, &postprologue_addr))
return;
*entrypc = postprologue_addr;
}