diff options
Diffstat (limited to 'tools/perf/util/dwarf-aux.c')
| -rw-r--r-- | tools/perf/util/dwarf-aux.c | 1511 |
1 files changed, 1397 insertions, 114 deletions
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 3e5f5430a28a..9267af204c7d 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -1,26 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * 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 <errno.h> +#include <inttypes.h> #include <stdbool.h> -#include "util.h" +#include <stdlib.h> #include "debug.h" #include "dwarf-aux.h" +#include "dwarf-regs.h" +#include "strbuf.h" +#include "string2.h" /** * cu_find_realpath - Find the realpath of the target file @@ -69,6 +60,51 @@ const char *cu_get_comp_dir(Dwarf_Die *cu_die) 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 @@ -78,22 +114,31 @@ const char *cu_get_comp_dir(Dwarf_Die *cu_die) * * 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) +int cu_find_lineinfo(Dwarf_Die *cu_die, Dwarf_Addr addr, + const char **fname, int *lineno) { Dwarf_Line *line; - Dwarf_Addr laddr; + 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 = dwarf_getsrc_die(cu_die, (Dwarf_Addr)addr); - if (line && dwarf_lineaddr(line, &laddr) == 0 && - addr == (unsigned long)laddr && dwarf_lineno(line, lineno) == 0) { + 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; } - return *lineno ?: -ENOENT; +out: + return (*lineno && *fname) ? *lineno : -ENOENT; } static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data); @@ -130,6 +175,22 @@ int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr, } /** + * 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 @@ -139,11 +200,35 @@ int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr, 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 * @@ -182,7 +267,7 @@ Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) } /* Get a type die, but skip qualifiers */ -static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) +Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) { int tag; @@ -224,26 +309,13 @@ static int die_get_attr_udata(Dwarf_Die *tp_die, unsigned int attr_name, { Dwarf_Attribute attr; - if (dwarf_attr(tp_die, attr_name, &attr) == NULL || + if (dwarf_attr_integrate(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 @@ -263,6 +335,90 @@ bool die_is_signed_type(Dwarf_Die *tp_die) } /** + * 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 @@ -299,9 +455,9 @@ int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs) /* Get the call file index number in CU DIE */ static int die_get_call_fileno(Dwarf_Die *in_die) { - Dwarf_Sword idx; + Dwarf_Word idx; - if (die_get_attr_sdata(in_die, DW_AT_call_file, &idx) == 0) + if (die_get_attr_udata(in_die, DW_AT_call_file, &idx) == 0) return (int)idx; else return -ENOENT; @@ -310,14 +466,29 @@ static int die_get_call_fileno(Dwarf_Die *in_die) /* Get the declared file index number in CU DIE */ static int die_get_decl_fileno(Dwarf_Die *pdie) { - Dwarf_Sword idx; + Dwarf_Word idx; - if (die_get_attr_sdata(pdie, DW_AT_decl_file, &idx) == 0) + 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 @@ -327,18 +498,22 @@ static int die_get_decl_fileno(Dwarf_Die *pdie) */ 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); + 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 @@ -387,11 +562,52 @@ struct __addr_die_search_param { 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)); @@ -407,7 +623,7 @@ static int __die_search_func_cb(Dwarf_Die *fn_die, void *data) * @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. + * 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) @@ -435,15 +651,32 @@ static int __die_find_inline_cb(Dwarf_Die *die_mem, void *data) } /** + * 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 - * @cu_die: a CU DIE which including @addr + * @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. + * 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. + * it down and returns deepest one. */ Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, Dwarf_Die *die_mem) @@ -464,6 +697,49 @@ Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, return die_mem; } +static int __die_find_func_rettype_cb(Dwarf_Die *die_mem, void *data) +{ + const char *func_name; + + if (dwarf_tag(die_mem) != DW_TAG_subprogram) + return DIE_FIND_CB_SIBLING; + + func_name = dwarf_diename(die_mem); + if (func_name && !strcmp(func_name, data)) + return DIE_FIND_CB_END; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_find_func_rettype - Search a return type of function + * @cu_die: a CU DIE + * @name: target function name + * @die_mem: a buffer for result DIE + * + * Search a non-inlined function which matches to @name and stores the + * return type of the function to @die_mem and returns it if found. + * Returns NULL if failed. Note that it doesn't needs to find a + * definition of the function, so it doesn't match with address. + * Most likely, it can find a declaration at the top level. Thus the + * callback function continues to sibling entries only. + */ +Dwarf_Die *die_find_func_rettype(Dwarf_Die *cu_die, const char *name, + Dwarf_Die *die_mem) +{ + Dwarf_Die tmp_die; + + cu_die = die_find_child(cu_die, __die_find_func_rettype_cb, + (void *)name, &tmp_die); + if (!cu_die) + return NULL; + + if (die_get_real_type(&tmp_die, die_mem) == NULL) + return NULL; + + return die_mem; +} + struct __instance_walk_param { void *addr; int (*callback)(Dwarf_Die *, void *); @@ -480,6 +756,9 @@ static int __die_walk_instances_cb(Dwarf_Die *inst, void *data) 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; @@ -510,7 +789,7 @@ static int __die_walk_instances_cb(Dwarf_Die *inst, void *data) * @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 + * 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 *), @@ -551,18 +830,17 @@ static int __die_walk_funclines_cb(Dwarf_Die *in_die, void *data) 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) { + 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 (!lw->recursive) - /* Don't need to search recursively */ - return DIE_FIND_CB_SIBLING; if (addr) { - fname = dwarf_decl_file(in_die); + 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) @@ -590,9 +868,9 @@ static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive, int lineno; /* Handle function declaration line */ - fname = dwarf_decl_file(sp_die); + fname = die_get_decl_file(sp_die); if (fname && dwarf_decl_line(sp_die, &lineno) == 0 && - dwarf_entrypc(sp_die, &addr) == 0) { + die_entrypc(sp_die, &addr) == 0) { lw.retval = callback(fname, lineno, addr, data); if (lw.retval != 0) goto done; @@ -606,6 +884,10 @@ 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; @@ -630,15 +912,24 @@ 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; + 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) + if (dwarf_tag(rt_die) != DW_TAG_compile_unit) { cu_die = dwarf_diecu(rt_die, &die_mem, NULL, NULL); - else + 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"); @@ -662,16 +953,36 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data) "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) + 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)) + 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); @@ -686,8 +997,9 @@ int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback, void *data) */ if (rt_die != cu_die) /* - * Don't need walk functions recursively, because nested - * inlined functions don't have lines of the specified 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 { @@ -711,14 +1023,21 @@ struct __find_variable_param { 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)) + 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 @@ -747,10 +1066,16 @@ 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; - + 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; } @@ -770,76 +1095,1034 @@ Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name, } /** - * 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 + * die_get_typename_from_type - Get the name of given type DIE + * @type_die: a type DIE + * @buf: a strbuf for result type name * - * 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. + * Get the name of @type_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, char *buf, int len) +int die_get_typename_from_type(Dwarf_Die *type_die, struct strbuf *buf) { - Dwarf_Die type; - int tag, ret, ret2; + 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) + tag = dwarf_tag(type_die); + if (tag == DW_TAG_pointer_type) tmp = "*"; + else if (tag == DW_TAG_array_type) + tmp = "[]"; else if (tag == DW_TAG_subroutine_type) { /* Function pointer */ - ret = snprintf(buf, len, "(function_type)"); - return (ret >= len) ? -E2BIG : ret; + return strbuf_add(buf, "(function_type)", 15); } else { - if (!dwarf_diename(&type)) - return -ENOENT; + const char *name = dwarf_diename(type_die); + 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 */ - ret = snprintf(buf, len, "%s%s", tmp, dwarf_diename(&type)); - return (ret >= len) ? -E2BIG : ret; + return strbuf_addf(buf, "%s%s", tmp, name ?: ""); } - 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; + ret = die_get_typename(type_die, buf); + if (ret < 0) { + /* void pointer has no type attribute */ + if (tag == DW_TAG_pointer_type && ret == -ENOENT) + return strbuf_addf(buf, "void*"); + + return ret; } - return ret; + return strbuf_addstr(buf, tmp); +} + +/** + * 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; + + if (__die_get_real_type(vr_die, &type) == NULL) + return -ENOENT; + + return die_get_typename_from_type(&type, buf); } /** * 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 + * @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, char *buf, int len) +int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf) { - int ret, ret2; + int ret; - ret = die_get_typename(vr_die, buf, len); + ret = die_get_typename(vr_die, buf); if (ret < 0) { pr_debug("Failed to get type, make it unknown.\n"); - ret = snprintf(buf, len, "(unknown_type)"); + ret = strbuf_add(buf, "(unknown_type)", 14); + } + + return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die)); +} + +static int reg_from_dwarf_op(Dwarf_Op *op) +{ + switch (op->atom) { + case DW_OP_reg0 ... DW_OP_reg31: + return op->atom - DW_OP_reg0; + case DW_OP_breg0 ... DW_OP_breg31: + return op->atom - DW_OP_breg0; + case DW_OP_regx: + case DW_OP_bregx: + return op->number; + case DW_OP_fbreg: + return DWARF_REG_FB; + default: + break; + } + return -1; +} + +static int offset_from_dwarf_op(Dwarf_Op *op) +{ + switch (op->atom) { + case DW_OP_reg0 ... DW_OP_reg31: + case DW_OP_regx: + return 0; + case DW_OP_breg0 ... DW_OP_breg31: + case DW_OP_fbreg: + return op->number; + case DW_OP_bregx: + return op->number2; + default: + break; + } + return -1; +} + +static bool check_allowed_ops(Dwarf_Op *ops, size_t nops) +{ + /* The first op is checked separately */ + ops++; + nops--; + + /* + * It needs to make sure if the location expression matches to the given + * register and offset exactly. Thus it rejects any complex expressions + * and only allows a few of selected operators that doesn't change the + * location. + */ + while (nops) { + switch (ops->atom) { + case DW_OP_stack_value: + case DW_OP_deref_size: + case DW_OP_deref: + case DW_OP_piece: + break; + default: + return false; + } + ops++; + nops--; + } + return true; +} + +/** + * 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 (ret > 0) { - ret2 = snprintf(buf + ret, len - ret, "\t%s", - dwarf_diename(vr_die)); - ret = (ret2 >= len - ret) ? -E2BIG : ret2 + ret; + + 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; } +/* Interval parameters for __die_find_var_reg_cb() */ +struct find_var_data { + /* Target instruction address */ + Dwarf_Addr pc; + /* Target memory address (for global data) */ + Dwarf_Addr addr; + /* Target register */ + unsigned reg; + /* Access offset, set for global data */ + int offset; + /* True if the current register is the frame base */ + bool is_fbreg; +}; + +/* Max number of registers DW_OP_regN supports */ +#define DWARF_OP_DIRECT_REGS 32 + +static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data, + s64 addr_offset, s64 addr_type, bool is_pointer) +{ + Dwarf_Die type_die; + Dwarf_Word size; + s64 offset = addr_offset - addr_type; + + if (offset == 0) { + /* Update offset relative to the start of the variable */ + data->offset = 0; + return true; + } + + if (offset < 0) + return false; + + if (die_get_real_type(die_mem, &type_die) == NULL) + return false; + + if (is_pointer && dwarf_tag(&type_die) == DW_TAG_pointer_type) { + /* Get the target type of the pointer */ + if (die_get_real_type(&type_die, &type_die) == NULL) + return false; + } + + if (dwarf_aggregate_size(&type_die, &size) < 0) + return false; + + if ((u64)offset >= size) + return false; + + /* Update offset relative to the start of the variable */ + data->offset = offset; + return true; +} + +/** + * is_breg_access_indirect - Check if breg based access implies type + * dereference + * @ops: DWARF operations array + * @nops: Number of operations in @ops + * + * Returns true if the DWARF expression evaluates to the variable's + * value, so the memory access on that register needs type dereference. + * Returns false if the expression evaluates to the variable's address. + * This is called after check_allowed_ops. + */ +static bool is_breg_access_indirect(Dwarf_Op *ops, size_t nops) +{ + /* only the base register */ + if (nops == 1) + return false; + + if (nops == 2 && ops[1].atom == DW_OP_stack_value) + return true; + + if (nops == 3 && (ops[1].atom == DW_OP_deref || + ops[1].atom == DW_OP_deref_size) && + ops[2].atom == DW_OP_stack_value) + return false; + /* unreachable, OP not supported */ + return false; +} + +/* Only checks direct child DIEs in the given scope. */ +static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) +{ + struct find_var_data *data = arg; + int tag = dwarf_tag(die_mem); + ptrdiff_t off = 0; + Dwarf_Attribute attr; + Dwarf_Addr base, start, end; + Dwarf_Op *ops; + size_t nops; + + if (tag != DW_TAG_variable && tag != DW_TAG_formal_parameter) + return DIE_FIND_CB_SIBLING; + + if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL) + return DIE_FIND_CB_SIBLING; + + while ((off = dwarf_getlocations(&attr, off, &base, &start, &end, &ops, &nops)) > 0) { + /* Assuming the location list is sorted by address */ + if (end <= data->pc) + continue; + if (start > data->pc) + break; + + /* Local variables accessed using frame base register */ + if (data->is_fbreg && ops->atom == DW_OP_fbreg && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, ops->number, + is_breg_access_indirect(ops, nops))) + return DIE_FIND_CB_END; + + /* Only match with a simple case */ + if (data->reg < DWARF_OP_DIRECT_REGS) { + /* pointer variables saved in a register 0 to 31 */ + if (ops->atom == (DW_OP_reg0 + data->reg) && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, 0, + /*is_pointer=*/true)) + return DIE_FIND_CB_END; + + /* variables accessed by a register + offset */ + if (ops->atom == (DW_OP_breg0 + data->reg) && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, ops->number, + is_breg_access_indirect(ops, nops))) + return DIE_FIND_CB_END; + } else { + /* pointer variables saved in a register 32 or above */ + if (ops->atom == DW_OP_regx && ops->number == data->reg && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, 0, + /*is_pointer=*/true)) + return DIE_FIND_CB_END; + + /* variables accessed by a register + offset */ + if (ops->atom == DW_OP_bregx && data->reg == ops->number && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, ops->number2, + is_breg_access_indirect(ops, nops))) + return DIE_FIND_CB_END; + } + } + return DIE_FIND_CB_SIBLING; +} + +/** + * die_find_variable_by_reg - Find a variable saved in a register + * @sc_die: a scope DIE + * @pc: the program address to find + * @reg: the register number to find + * @poffset: pointer to offset, will be updated for fbreg case + * @is_fbreg: boolean value if the current register is the frame base + * @die_mem: a buffer to save the resulting DIE + * + * Find the variable DIE accessed by the given register. It'll update the @offset + * when the variable is in the stack. + */ +Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg, + int *poffset, bool is_fbreg, + Dwarf_Die *die_mem) +{ + struct find_var_data data = { + .pc = pc, + .reg = reg, + .offset = *poffset, + .is_fbreg = is_fbreg, + }; + Dwarf_Die *result; + + result = die_find_child(sc_die, __die_find_var_reg_cb, &data, die_mem); + if (result) + *poffset = data.offset; + return result; +} + +/* Only checks direct child DIEs in the given scope */ +static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) +{ + struct find_var_data *data = arg; + int tag = dwarf_tag(die_mem); + ptrdiff_t off = 0; + Dwarf_Attribute attr; + Dwarf_Addr base, start, end; + Dwarf_Op *ops; + size_t nops; + + if (tag != DW_TAG_variable) + return DIE_FIND_CB_SIBLING; + + if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL) + return DIE_FIND_CB_SIBLING; + + while ((off = dwarf_getlocations(&attr, off, &base, &start, &end, &ops, &nops)) > 0) { + if (ops->atom != DW_OP_addr) + continue; + + if (check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->addr, ops->number, + /*is_pointer=*/false)) + return DIE_FIND_CB_END; + } + return DIE_FIND_CB_SIBLING; +} + +/** + * die_find_variable_by_addr - Find variable located at given address + * @sc_die: a scope DIE + * @addr: the data address to find + * @die_mem: a buffer to save the resulting DIE + * @offset: the offset in the resulting type + * + * Find the variable DIE located at the given address (in PC-relative mode). + * This is usually for global variables. + */ +Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr addr, + Dwarf_Die *die_mem, int *offset) +{ + struct find_var_data data = { + .addr = addr, + }; + Dwarf_Die *result; + + result = die_find_child(sc_die, __die_find_var_addr_cb, &data, die_mem); + if (result) + *offset = data.offset; + return result; +} + +static int __die_collect_vars_cb(Dwarf_Die *die_mem, void *arg) +{ + struct die_var_type **var_types = arg; + Dwarf_Die type_die; + int tag = dwarf_tag(die_mem); + Dwarf_Attribute attr; + Dwarf_Addr base, start, end; + Dwarf_Op *ops; + size_t nops; + struct die_var_type *vt; + + if (tag != DW_TAG_variable && tag != DW_TAG_formal_parameter) + return DIE_FIND_CB_SIBLING; + + if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL) + return DIE_FIND_CB_SIBLING; + + /* + * Only collect the first location as it can reconstruct the + * remaining state by following the instructions. + * start = 0 means it covers the whole range. + */ + if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0) + return DIE_FIND_CB_SIBLING; + + if (!check_allowed_ops(ops, nops)) + return DIE_FIND_CB_SIBLING; + + if (__die_get_real_type(die_mem, &type_die) == NULL) + return DIE_FIND_CB_SIBLING; + + vt = malloc(sizeof(*vt)); + if (vt == NULL) + return DIE_FIND_CB_END; + + /* Usually a register holds the value of a variable */ + vt->is_reg_var_addr = false; + + if (((ops->atom >= DW_OP_breg0 && ops->atom <= DW_OP_breg31) || + ops->atom == DW_OP_bregx || ops->atom == DW_OP_fbreg) && + !is_breg_access_indirect(ops, nops)) + /* The register contains an address of the variable. */ + vt->is_reg_var_addr = true; + + vt->die_off = dwarf_dieoffset(&type_die); + vt->addr = start; + vt->reg = reg_from_dwarf_op(ops); + vt->offset = offset_from_dwarf_op(ops); + vt->next = *var_types; + *var_types = vt; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_collect_vars - Save all variables and parameters + * @sc_die: a scope DIE + * @var_types: a pointer to save the resulting list + * + * Save all variables and parameters in the @sc_die and save them to @var_types. + * The @var_types is a singly-linked list containing type and location info. + * Actual type can be retrieved using dwarf_offdie() with 'die_off' later. + * + * Callers should free @var_types. + */ +void die_collect_vars(Dwarf_Die *sc_die, struct die_var_type **var_types) +{ + Dwarf_Die die_mem; + + die_find_child(sc_die, __die_collect_vars_cb, (void *)var_types, &die_mem); +} + +static int __die_collect_global_vars_cb(Dwarf_Die *die_mem, void *arg) +{ + struct die_var_type **var_types = arg; + Dwarf_Die type_die; + int tag = dwarf_tag(die_mem); + Dwarf_Attribute attr; + Dwarf_Addr base, start, end; + Dwarf_Op *ops; + size_t nops; + struct die_var_type *vt; + + if (tag != DW_TAG_variable) + return DIE_FIND_CB_SIBLING; + + if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL) + return DIE_FIND_CB_SIBLING; + + /* Only collect the location with an absolute address. */ + if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0) + return DIE_FIND_CB_SIBLING; + + if (ops->atom != DW_OP_addr) + return DIE_FIND_CB_SIBLING; + + if (!check_allowed_ops(ops, nops)) + return DIE_FIND_CB_SIBLING; + + if (die_get_real_type(die_mem, &type_die) == NULL) + return DIE_FIND_CB_SIBLING; + + vt = malloc(sizeof(*vt)); + if (vt == NULL) + return DIE_FIND_CB_END; + + vt->die_off = dwarf_dieoffset(&type_die); + vt->addr = ops->number; + vt->reg = -1; + vt->offset = 0; + vt->next = *var_types; + *var_types = vt; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_collect_global_vars - Save all global variables + * @cu_die: a CU DIE + * @var_types: a pointer to save the resulting list + * + * Save all global variables in the @cu_die and save them to @var_types. + * The @var_types is a singly-linked list containing type and location info. + * Actual type can be retrieved using dwarf_offdie() with 'die_off' later. + * + * Callers should free @var_types. + */ +void die_collect_global_vars(Dwarf_Die *cu_die, struct die_var_type **var_types) +{ + Dwarf_Die die_mem; + + die_find_child(cu_die, __die_collect_global_vars_cb, (void *)var_types, &die_mem); +} + +/** + * die_get_cfa - Get frame base information + * @dwarf: a Dwarf info + * @pc: program address + * @preg: pointer for saved register + * @poffset: pointer for saved offset + * + * This function gets register and offset for CFA (Canonical Frame Address) + * by searching the CIE/FDE info. The CFA usually points to the start address + * of the current stack frame and local variables can be located using an offset + * from the CFA. The @preg and @poffset will be updated if it returns 0. + */ +int die_get_cfa(Dwarf *dwarf, u64 pc, int *preg, int *poffset) +{ + Dwarf_CFI *cfi; + Dwarf_Frame *frame = NULL; + Dwarf_Op *ops = NULL; + size_t nops; + + cfi = dwarf_getcfi(dwarf); + if (cfi == NULL) + return -1; + + if (!dwarf_cfi_addrframe(cfi, pc, &frame) && + !dwarf_frame_cfa(frame, &ops, &nops) && + check_allowed_ops(ops, nops)) { + *preg = reg_from_dwarf_op(ops); + *poffset = offset_from_dwarf_op(ops); + return 0; + } + return -1; +} + +/* + * 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; +} + +/* Internal parameters for __die_find_scope_cb() */ +struct find_scope_data { + /* Target instruction address */ + Dwarf_Addr pc; + /* Number of scopes found [output] */ + int nr; + /* Array of scopes found, 0 for the outermost one. [output] */ + Dwarf_Die *scopes; +}; + +static int __die_find_scope_cb(Dwarf_Die *die_mem, void *arg) +{ + struct find_scope_data *data = arg; + int tag = dwarf_tag(die_mem); + + if (dwarf_haspc(die_mem, data->pc)) { + Dwarf_Die *tmp; + + tmp = realloc(data->scopes, (data->nr + 1) * sizeof(*tmp)); + if (tmp == NULL) + return DIE_FIND_CB_END; + + memcpy(tmp + data->nr, die_mem, sizeof(*die_mem)); + data->scopes = tmp; + data->nr++; + return DIE_FIND_CB_CHILD; + } + + /* + * If the DIE doesn't have the PC, we still need to check its children + * and siblings if it's a container like a namespace. + */ + if (tag == DW_TAG_namespace) + return DIE_FIND_CB_CONTINUE; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_get_scopes - Return a list of scopes including the address + * @cu_die: a compile unit DIE + * @pc: the address to find + * @scopes: the array of DIEs for scopes (result) + * + * This function does the same as the dwarf_getscopes() but doesn't follow + * the origins of inlined functions. It returns the number of scopes saved + * in the @scopes argument. The outer scope will be saved first (index 0) and + * the last one is the innermost scope at the @pc. + */ +int die_get_scopes(Dwarf_Die *cu_die, Dwarf_Addr pc, Dwarf_Die **scopes) +{ + struct find_scope_data data = { + .pc = pc, + }; + Dwarf_Die die_mem; + + die_find_child(cu_die, __die_find_scope_cb, &data, &die_mem); + + *scopes = data.scopes; + return data.nr; +} + +static int __die_find_member_offset_cb(Dwarf_Die *die_mem, void *arg) +{ + Dwarf_Die type_die; + Dwarf_Word size, loc; + Dwarf_Word offset = (long)arg; + int tag = dwarf_tag(die_mem); + + if (tag != DW_TAG_member) + return DIE_FIND_CB_SIBLING; + + /* Unions might not have location */ + if (die_get_data_member_location(die_mem, &loc) < 0) { + Dwarf_Attribute attr; + + if (dwarf_attr_integrate(die_mem, DW_AT_data_bit_offset, &attr) && + dwarf_formudata(&attr, &loc) == 0) + loc /= 8; + else + loc = 0; + } + + if (offset == loc) + return DIE_FIND_CB_END; + + if (die_get_real_type(die_mem, &type_die) == NULL) { + // TODO: add a pr_debug_dtp() later for this unlikely failure + return DIE_FIND_CB_SIBLING; + } + + if (dwarf_aggregate_size(&type_die, &size) < 0) + size = 0; + + if (loc < offset && offset < (loc + size)) + return DIE_FIND_CB_END; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_get_member_type - Return type info of struct member + * @type_die: a type DIE + * @offset: offset in the type + * @die_mem: a buffer to save the resulting DIE + * + * This function returns a type of a member in @type_die where it's located at + * @offset if it's a struct. For now, it just returns the first matching + * member in a union. For other types, it'd return the given type directly + * if it's within the size of the type or NULL otherwise. + */ +Dwarf_Die *die_get_member_type(Dwarf_Die *type_die, int offset, + Dwarf_Die *die_mem) +{ + Dwarf_Die *member; + Dwarf_Die mb_type; + int tag; + + tag = dwarf_tag(type_die); + /* If it's not a compound type, return the type directly */ + if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) { + Dwarf_Word size; + + if (dwarf_aggregate_size(type_die, &size) < 0) + size = 0; + + if ((unsigned)offset >= size) + return NULL; + + *die_mem = *type_die; + return die_mem; + } + + mb_type = *type_die; + /* TODO: Handle union types better? */ + while (tag == DW_TAG_structure_type || tag == DW_TAG_union_type) { + member = die_find_child(&mb_type, __die_find_member_offset_cb, + (void *)(long)offset, die_mem); + if (member == NULL) + return NULL; + + if (die_get_real_type(member, &mb_type) == NULL) + return NULL; + + tag = dwarf_tag(&mb_type); + + if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type) { + Dwarf_Word loc; + + /* Update offset for the start of the member struct */ + if (die_get_data_member_location(member, &loc) == 0) + offset -= loc; + } + } + *die_mem = mb_type; + return die_mem; +} + +/** + * die_deref_ptr_type - Return type info for pointer access + * @ptr_die: a pointer type DIE + * @offset: access offset for the pointer + * @die_mem: a buffer to save the resulting DIE + * + * This function follows the pointer in @ptr_die with given @offset + * and saves the resulting type in @die_mem. If the pointer points + * a struct type, actual member at the offset would be returned. + */ +Dwarf_Die *die_deref_ptr_type(Dwarf_Die *ptr_die, int offset, + Dwarf_Die *die_mem) +{ + Dwarf_Die type_die; + + if (dwarf_tag(ptr_die) != DW_TAG_pointer_type) + return NULL; + + if (die_get_real_type(ptr_die, &type_die) == NULL) + return NULL; + + return die_get_member_type(&type_die, offset, die_mem); +} |