// 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 "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); } /** * 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; } 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 attiribute 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(tp_die, attr_name, &attr) == NULL || dwarf_formudata(&attr, result) != 0) return -ENOENT; return 0; } /* Get attribute and translate it as a sdata */ static int die_get_attr_sdata(Dwarf_Die *tp_die, unsigned int attr_name, Dwarf_Sword *result) { Dwarf_Attribute attr; if (dwarf_attr(tp_die, attr_name, &attr) == NULL || dwarf_formsdata(&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; return (dwarf_tag(dw_die) == DW_TAG_subprogram && dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL); } /** * 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, you need to * call die_walk_instances() to find actual instances. **/ bool die_is_func_instance(Dwarf_Die *dw_die) { Dwarf_Addr tmp; /* Actually gcc optimizes non-inline as like as inlined */ return !dwarf_func_inline(dw_die) && dwarf_entrypc(dw_die, &tmp) == 0; } /** * 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_Sword idx; if (die_get_attr_sdata(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_Sword idx; if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0) return (int)idx; else return -ENOENT; } /** * 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) { Dwarf_Die cu_die; Dwarf_Files *files; int idx; idx = die_get_call_fileno(in_die); if (idx < 0 || !dwarf_diecu(in_die, &cu_die, NULL, NULL) || dwarf_getsrcfiles(&cu_die, &files, NULL) != 0) return NULL; return dwarf_filesrc(files, idx, NULL, NULL); } /** * 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; 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 * declartion. 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 && dwarf_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) /* Don't need to search recursively */ return DIE_FIND_CB_SIBLING; if (addr) { fname = dwarf_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 = dwarf_decl_file(sp_die); if (fname && dwarf_decl_line(sp_die, &lineno) == 0 && dwarf_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; 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; int lineno, ret = 0; int decl = 0, inl; 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); dwarf_decl_line(rt_die, &decl); decf = dwarf_decl_file(rt_die); } 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)) continue; if (die_find_inlinefunc(rt_die, addr, &die_mem)) { dwarf_decl_line(&die_mem, &inl); if (inl != decl || decf != dwarf_decl_file(&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) /* * Don't need walk functions recursively, because nested * inlined functions don't have lines of the specified DIE. */ 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 external instance? */ (dwarf_attr(die_mem, DW_AT_external, &attr) || dwarf_attr(die_mem, DW_AT_location, &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 { if (!dwarf_diename(&type)) return -ENOENT; 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 "; /* Write a base name */ return strbuf_addf(buf, "%s%s", tmp, dwarf_diename(&type)); } 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 = dwarf_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 = dwarf_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; }