diff options
Diffstat (limited to 'tools/perf/util/probe-finder.c')
| -rw-r--r-- | tools/perf/util/probe-finder.c | 677 |
1 files changed, 677 insertions, 0 deletions
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c new file mode 100644 index 00000000000..be997abdf5b --- /dev/null +++ b/tools/perf/util/probe-finder.c @@ -0,0 +1,677 @@ +/* + * probe-finder.c : C expression to kprobe event converter + * + * Written by Masami Hiramatsu <mhiramat@redhat.com> + * + * 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 <sys/utsname.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <errno.h> +#include <stdio.h> +#include <unistd.h> +#include <getopt.h> +#include <stdlib.h> +#include <string.h> +#include <stdarg.h> +#include <ctype.h> + +#include "event.h" +#include "debug.h" +#include "util.h" +#include "probe-finder.h" + + +/* Dwarf_Die Linkage to parent Die */ +struct die_link { + struct die_link *parent; /* Parent die */ + Dwarf_Die die; /* Current die */ +}; + +static Dwarf_Debug __dw_debug; +static Dwarf_Error __dw_error; + +/* + * Generic dwarf analysis helpers + */ + +#define X86_32_MAX_REGS 8 +const char *x86_32_regs_table[X86_32_MAX_REGS] = { + "%ax", + "%cx", + "%dx", + "%bx", + "$stack", /* Stack address instead of %sp */ + "%bp", + "%si", + "%di", +}; + +#define X86_64_MAX_REGS 16 +const char *x86_64_regs_table[X86_64_MAX_REGS] = { + "%ax", + "%dx", + "%cx", + "%bx", + "%si", + "%di", + "%bp", + "%sp", + "%r8", + "%r9", + "%r10", + "%r11", + "%r12", + "%r13", + "%r14", + "%r15", +}; + +/* TODO: switching by dwarf address size */ +#ifdef __x86_64__ +#define ARCH_MAX_REGS X86_64_MAX_REGS +#define arch_regs_table x86_64_regs_table +#else +#define ARCH_MAX_REGS X86_32_MAX_REGS +#define arch_regs_table x86_32_regs_table +#endif + +/* Return architecture dependent register string (for kprobe-tracer) */ +static const char *get_arch_regstr(unsigned int n) +{ + return (n <= ARCH_MAX_REGS) ? arch_regs_table[n] : NULL; +} + +/* + * Compare the tail of two strings. + * Return 0 if whole of either string is same as another's tail part. + */ +static int strtailcmp(const char *s1, const char *s2) +{ + int i1 = strlen(s1); + int i2 = strlen(s2); + while (--i1 > 0 && --i2 > 0) { + if (s1[i1] != s2[i2]) + return s1[i1] - s2[i2]; + } + return 0; +} + +/* Find the fileno of the target file. */ +static Dwarf_Unsigned die_get_fileno(Dwarf_Die cu_die, const char *fname) +{ + Dwarf_Signed cnt, i; + Dwarf_Unsigned found = 0; + char **srcs; + int ret; + + if (!fname) + return 0; + + ret = dwarf_srcfiles(cu_die, &srcs, &cnt, &__dw_error); + if (ret == DW_DLV_OK) { + for (i = 0; i < cnt && !found; i++) { + if (strtailcmp(srcs[i], fname) == 0) + found = i + 1; + dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING); + } + for (; i < cnt; i++) + dwarf_dealloc(__dw_debug, srcs[i], DW_DLA_STRING); + dwarf_dealloc(__dw_debug, srcs, DW_DLA_LIST); + } + if (found) + eprintf("found fno: %d\n", (int)found); + return found; +} + +/* Compare diename and tname */ +static int die_compare_name(Dwarf_Die dw_die, const char *tname) +{ + char *name; + int ret; + ret = dwarf_diename(dw_die, &name, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + ret = strcmp(tname, name); + dwarf_dealloc(__dw_debug, name, DW_DLA_STRING); + } else + ret = -1; + return ret; +} + +/* Check the address is in the subprogram(function). */ +static int die_within_subprogram(Dwarf_Die sp_die, Dwarf_Addr addr, + Dwarf_Signed *offs) +{ + Dwarf_Addr lopc, hipc; + int ret; + + /* TODO: check ranges */ + ret = dwarf_lowpc(sp_die, &lopc, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_NO_ENTRY) + return 0; + ret = dwarf_highpc(sp_die, &hipc, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + if (lopc <= addr && addr < hipc) { + *offs = addr - lopc; + return 1; + } else + return 0; +} + +/* Check the die is inlined function */ +static Dwarf_Bool die_inlined_subprogram(Dwarf_Die dw_die) +{ + /* TODO: check strictly */ + Dwarf_Bool inl; + int ret; + + ret = dwarf_hasattr(dw_die, DW_AT_inline, &inl, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + return inl; +} + +/* Get the offset of abstruct_origin */ +static Dwarf_Off die_get_abstract_origin(Dwarf_Die dw_die) +{ + Dwarf_Attribute attr; + Dwarf_Off cu_offs; + int ret; + + ret = dwarf_attr(dw_die, DW_AT_abstract_origin, &attr, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + ret = dwarf_formref(attr, &cu_offs, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); + return cu_offs; +} + +/* Get entry pc(or low pc, 1st entry of ranges) of the die */ +static Dwarf_Addr die_get_entrypc(Dwarf_Die dw_die) +{ + Dwarf_Attribute attr; + Dwarf_Addr addr; + Dwarf_Off offs; + Dwarf_Ranges *ranges; + Dwarf_Signed cnt; + int ret; + + /* Try to get entry pc */ + ret = dwarf_attr(dw_die, DW_AT_entry_pc, &attr, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + ret = dwarf_formaddr(attr, &addr, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); + return addr; + } + + /* Try to get low pc */ + ret = dwarf_lowpc(dw_die, &addr, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) + return addr; + + /* Try to get ranges */ + ret = dwarf_attr(dw_die, DW_AT_ranges, &attr, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + ret = dwarf_formref(attr, &offs, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + ret = dwarf_get_ranges(__dw_debug, offs, &ranges, &cnt, NULL, + &__dw_error); + DIE_IF(ret != DW_DLV_OK); + addr = ranges[0].dwr_addr1; + dwarf_ranges_dealloc(__dw_debug, ranges, cnt); + return addr; +} + +/* + * Search a Die from Die tree. + * Note: cur_link->die should be deallocated in this function. + */ +static int __search_die_tree(struct die_link *cur_link, + int (*die_cb)(struct die_link *, void *), + void *data) +{ + Dwarf_Die new_die; + struct die_link new_link; + int ret; + + if (!die_cb) + return 0; + + /* Check current die */ + while (!(ret = die_cb(cur_link, data))) { + /* Check child die */ + ret = dwarf_child(cur_link->die, &new_die, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + new_link.parent = cur_link; + new_link.die = new_die; + ret = __search_die_tree(&new_link, die_cb, data); + if (ret) + break; + } + + /* Move to next sibling */ + ret = dwarf_siblingof(__dw_debug, cur_link->die, &new_die, + &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE); + cur_link->die = new_die; + if (ret == DW_DLV_NO_ENTRY) + return 0; + } + dwarf_dealloc(__dw_debug, cur_link->die, DW_DLA_DIE); + return ret; +} + +/* Search a die in its children's die tree */ +static int search_die_from_children(Dwarf_Die parent_die, + int (*die_cb)(struct die_link *, void *), + void *data) +{ + struct die_link new_link; + int ret; + + new_link.parent = NULL; + ret = dwarf_child(parent_die, &new_link.die, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) + return __search_die_tree(&new_link, die_cb, data); + else + return 0; +} + +/* Find a locdesc corresponding to the address */ +static int attr_get_locdesc(Dwarf_Attribute attr, Dwarf_Locdesc *desc, + Dwarf_Addr addr) +{ + Dwarf_Signed lcnt; + Dwarf_Locdesc **llbuf; + int ret, i; + + ret = dwarf_loclist_n(attr, &llbuf, &lcnt, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + ret = DW_DLV_NO_ENTRY; + for (i = 0; i < lcnt; ++i) { + if (llbuf[i]->ld_lopc <= addr && + llbuf[i]->ld_hipc > addr) { + memcpy(desc, llbuf[i], sizeof(Dwarf_Locdesc)); + desc->ld_s = + malloc(sizeof(Dwarf_Loc) * llbuf[i]->ld_cents); + DIE_IF(desc->ld_s == NULL); + memcpy(desc->ld_s, llbuf[i]->ld_s, + sizeof(Dwarf_Loc) * llbuf[i]->ld_cents); + ret = DW_DLV_OK; + break; + } + dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK); + dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC); + } + /* Releasing loop */ + for (; i < lcnt; ++i) { + dwarf_dealloc(__dw_debug, llbuf[i]->ld_s, DW_DLA_LOC_BLOCK); + dwarf_dealloc(__dw_debug, llbuf[i], DW_DLA_LOCDESC); + } + dwarf_dealloc(__dw_debug, llbuf, DW_DLA_LIST); + return ret; +} + +/* + * Probe finder related functions + */ + +/* Show a location */ +static void show_location(Dwarf_Loc *loc, struct probe_finder *pf) +{ + Dwarf_Small op; + Dwarf_Unsigned regn; + Dwarf_Signed offs; + int deref = 0, ret; + const char *regs; + + op = loc->lr_atom; + + /* If this is based on frame buffer, set the offset */ + if (op == DW_OP_fbreg) { + deref = 1; + offs = (Dwarf_Signed)loc->lr_number; + op = pf->fbloc.ld_s[0].lr_atom; + loc = &pf->fbloc.ld_s[0]; + } else + offs = 0; + + if (op >= DW_OP_breg0 && op <= DW_OP_breg31) { + regn = op - DW_OP_breg0; + offs += (Dwarf_Signed)loc->lr_number; + deref = 1; + } else if (op >= DW_OP_reg0 && op <= DW_OP_reg31) { + regn = op - DW_OP_reg0; + } else if (op == DW_OP_bregx) { + regn = loc->lr_number; + offs += (Dwarf_Signed)loc->lr_number2; + deref = 1; + } else if (op == DW_OP_regx) { + regn = loc->lr_number; + } else + die("Dwarf_OP %d is not supported.\n", op); + + regs = get_arch_regstr(regn); + if (!regs) + die("%lld exceeds max register number.\n", regn); + + if (deref) + ret = snprintf(pf->buf, pf->len, + " %s=%+lld(%s)", pf->var, offs, regs); + else + ret = snprintf(pf->buf, pf->len, " %s=%s", pf->var, regs); + DIE_IF(ret < 0); + DIE_IF(ret >= pf->len); +} + +/* Show a variables in kprobe event format */ +static void show_variable(Dwarf_Die vr_die, struct probe_finder *pf) +{ + Dwarf_Attribute attr; + Dwarf_Locdesc ld; + int ret; + + ret = dwarf_attr(vr_die, DW_AT_location, &attr, &__dw_error); + if (ret != DW_DLV_OK) + goto error; + ret = attr_get_locdesc(attr, &ld, (pf->addr - pf->cu_base)); + if (ret != DW_DLV_OK) + goto error; + /* TODO? */ + DIE_IF(ld.ld_cents != 1); + show_location(&ld.ld_s[0], pf); + free(ld.ld_s); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); + return ; +error: + die("Failed to find the location of %s at this address.\n" + " Perhaps, it has been optimized out.\n", pf->var); +} + +static int variable_callback(struct die_link *dlink, void *data) +{ + struct probe_finder *pf = (struct probe_finder *)data; + Dwarf_Half tag; + int ret; + + ret = dwarf_tag(dlink->die, &tag, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if ((tag == DW_TAG_formal_parameter || + tag == DW_TAG_variable) && + (die_compare_name(dlink->die, pf->var) == 0)) { + show_variable(dlink->die, pf); + return 1; + } + /* TODO: Support struct members and arrays */ + return 0; +} + +/* Find a variable in a subprogram die */ +static void find_variable(Dwarf_Die sp_die, struct probe_finder *pf) +{ + int ret; + + if (!is_c_varname(pf->var)) { + /* Output raw parameters */ + ret = snprintf(pf->buf, pf->len, " %s", pf->var); + DIE_IF(ret < 0); + DIE_IF(ret >= pf->len); + return ; + } + + eprintf("Searching '%s' variable in context.\n", pf->var); + /* Search child die for local variables and parameters. */ + ret = search_die_from_children(sp_die, variable_callback, pf); + if (!ret) + die("Failed to find '%s' in this function.\n", pf->var); +} + +/* Get a frame base on the address */ +static void get_current_frame_base(Dwarf_Die sp_die, struct probe_finder *pf) +{ + Dwarf_Attribute attr; + int ret; + + ret = dwarf_attr(sp_die, DW_AT_frame_base, &attr, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + ret = attr_get_locdesc(attr, &pf->fbloc, (pf->addr - pf->cu_base)); + DIE_IF(ret != DW_DLV_OK); + dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR); +} + +static void free_current_frame_base(struct probe_finder *pf) +{ + free(pf->fbloc.ld_s); + memset(&pf->fbloc, 0, sizeof(Dwarf_Locdesc)); +} + +/* Show a probe point to output buffer */ +static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs, + struct probe_finder *pf) +{ + struct probe_point *pp = pf->pp; + char *name; + char tmp[MAX_PROBE_BUFFER]; + int ret, i, len; + + /* Output name of probe point */ + ret = dwarf_diename(sp_die, &name, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_OK) { + ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name, + (unsigned int)offs); + dwarf_dealloc(__dw_debug, name, DW_DLA_STRING); + } else { + /* This function has no name. */ + ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%llx", pf->addr); + } + DIE_IF(ret < 0); + DIE_IF(ret >= MAX_PROBE_BUFFER); + len = ret; + + /* Find each argument */ + get_current_frame_base(sp_die, pf); + for (i = 0; i < pp->nr_args; i++) { + pf->var = pp->args[i]; + pf->buf = &tmp[len]; + pf->len = MAX_PROBE_BUFFER - len; + find_variable(sp_die, pf); + len += strlen(pf->buf); + } + free_current_frame_base(pf); + + pp->probes[pp->found] = strdup(tmp); + pp->found++; +} + +static int probeaddr_callback(struct die_link *dlink, void *data) +{ + struct probe_finder *pf = (struct probe_finder *)data; + Dwarf_Half tag; + Dwarf_Signed offs; + int ret; + + ret = dwarf_tag(dlink->die, &tag, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + /* Check the address is in this subprogram */ + if (tag == DW_TAG_subprogram && + die_within_subprogram(dlink->die, pf->addr, &offs)) { + show_probepoint(dlink->die, offs, pf); + return 1; + } + return 0; +} + +/* Find probe point from its line number */ +static void find_by_line(Dwarf_Die cu_die, struct probe_finder *pf) +{ + struct probe_point *pp = pf->pp; + Dwarf_Signed cnt, i; + Dwarf_Line *lines; + Dwarf_Unsigned lineno = 0; + Dwarf_Addr addr; + Dwarf_Unsigned fno; + int ret; + + ret = dwarf_srclines(cu_die, &lines, &cnt, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + + for (i = 0; i < cnt; i++) { + ret = dwarf_line_srcfileno(lines[i], &fno, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + if (fno != pf->fno) + continue; + + ret = dwarf_lineno(lines[i], &lineno, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + if (lineno != (Dwarf_Unsigned)pp->line) + continue; + + ret = dwarf_lineaddr(lines[i], &addr, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + eprintf("Probe point found: 0x%llx\n", addr); + pf->addr = addr; + /* Search a real subprogram including this line, */ + ret = search_die_from_children(cu_die, probeaddr_callback, pf); + if (ret == 0) + die("Probe point is not found in subprograms.\n"); + /* Continuing, because target line might be inlined. */ + } + dwarf_srclines_dealloc(__dw_debug, lines, cnt); +} + +/* Search function from function name */ +static int probefunc_callback(struct die_link *dlink, void *data) +{ + struct probe_finder *pf = (struct probe_finder *)data; + struct probe_point *pp = pf->pp; + struct die_link *lk; + Dwarf_Signed offs; + Dwarf_Half tag; + int ret; + + ret = dwarf_tag(dlink->die, &tag, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (tag == DW_TAG_subprogram) { + if (die_compare_name(dlink->die, pp->function) == 0) { + if (die_inlined_subprogram(dlink->die)) { + /* Inlined function, save it. */ + ret = dwarf_die_CU_offset(dlink->die, + &pf->inl_offs, + &__dw_error); + DIE_IF(ret != DW_DLV_OK); + eprintf("inline definition offset %lld\n", + pf->inl_offs); + return 0; + } + /* Get probe address */ + pf->addr = die_get_entrypc(dlink->die); + pf->addr += pp->offset; + /* TODO: Check the address in this function */ + show_probepoint(dlink->die, pp->offset, pf); + /* Continue to search */ + } + } else if (tag == DW_TAG_inlined_subroutine && pf->inl_offs) { + if (die_get_abstract_origin(dlink->die) == pf->inl_offs) { + /* Get probe address */ + pf->addr = die_get_entrypc(dlink->die); + pf->addr += pp->offset; + eprintf("found inline addr: 0x%llx\n", pf->addr); + /* Inlined function. Get a real subprogram */ + for (lk = dlink->parent; lk != NULL; lk = lk->parent) { + tag = 0; + dwarf_tag(lk->die, &tag, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (tag == DW_TAG_subprogram && + !die_inlined_subprogram(lk->die)) + goto found; + } + die("Failed to find real subprogram.\n"); +found: + /* Get offset from subprogram */ + ret = die_within_subprogram(lk->die, pf->addr, &offs); + DIE_IF(!ret); + show_probepoint(lk->die, offs, pf); + /* Continue to search */ + } + } + return 0; +} + +static void find_by_func(Dwarf_Die cu_die, struct probe_finder *pf) +{ + search_die_from_children(cu_die, probefunc_callback, pf); +} + +/* Find a probe point */ +int find_probepoint(int fd, struct probe_point *pp) +{ + Dwarf_Half addr_size = 0; + Dwarf_Unsigned next_cuh = 0; + Dwarf_Die cu_die = 0; + int cu_number = 0, ret; + struct probe_finder pf = {.pp = pp}; + + ret = dwarf_init(fd, DW_DLC_READ, 0, 0, &__dw_debug, &__dw_error); + if (ret != DW_DLV_OK) + die("Failed to call dwarf_init(). Maybe, not a dwarf file.\n"); + + pp->found = 0; + while (++cu_number) { + /* Search CU (Compilation Unit) */ + ret = dwarf_next_cu_header(__dw_debug, NULL, NULL, NULL, + &addr_size, &next_cuh, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_NO_ENTRY) + break; + + /* Get the DIE(Debugging Information Entry) of this CU */ + ret = dwarf_siblingof(__dw_debug, 0, &cu_die, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + + /* Check if target file is included. */ + if (pp->file) + pf.fno = die_get_fileno(cu_die, pp->file); + + if (!pp->file || pf.fno) { + /* Save CU base address (for frame_base) */ + ret = dwarf_lowpc(cu_die, &pf.cu_base, &__dw_error); + DIE_IF(ret == DW_DLV_ERROR); + if (ret == DW_DLV_NO_ENTRY) + pf.cu_base = 0; + if (pp->line) + find_by_line(cu_die, &pf); + if (pp->function) + find_by_func(cu_die, &pf); + } + dwarf_dealloc(__dw_debug, cu_die, DW_DLA_DIE); + } + ret = dwarf_finish(__dw_debug, &__dw_error); + DIE_IF(ret != DW_DLV_OK); + + return pp->found; +} + |