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f7088df3b1
Joel contacted me offlist with a question about a warning that one of his customers was seeing. The message came from the new linker-debugger interface, which uses SDT probes internally. The warning said: (gdb) run [...] warning: Probes-based dynamic linker interface failed. Reverting to original interface. Argument to arithmetic operation not a number or boolean. This should not have happened in the environment the customer was using (RHEL-6.x), so I found it strange. Another thing caught my attention: the last message, saying "Argument to arithmetic operation not a number or boolean.". Joel kindly investigated the issue further, and found the answer for this. To quote him: (gdb) set lang c (gdb) p 48+$ebp $4 = (void *) 0xffffd0f8 So far so good. But... (gdb) set lang ada (gdb) p 48+$ebp Argument to arithmetic operation not a number or boolean. Ooops! Interestingly, if you revert the order of the operands... (gdb) p $ebp+48 $5 = (access void) 0xffffd0f8 So the problem is doing pointer arithmetics when the language is set to Ada. I remembered that, during the parsing and the evaluation of SDT probe arguments, the code sets the language as current_language, because, at that time, I thought it was not necessary to worry about the language given that the code implements its own parser. I was wrong. So here is a patch to fix that, by setting the language as C, which should guarantee that the maths are done in the right way (TM). It was somewhat hard to find a reproducer for this issue. In the end, what I had to do was to create a testcase that used the %ebp register on some displacement (e.g., "-4(%ebp)"), which finally triggered the bug. I am not sure why I could not trigger it when using other registers, but I did not want to spend too much time investigating this issue, which seemed like an Ada issue. Also, because of this peculiar way to trigger the problem, the testcase only covers x86-like targets (i.e., i*86 and x86_64 with -m32). Joel kindly tested this for me, and it worked. I also ran a full regression test here on my Fedora 20 x86_64, and everything is fine. I will push this patch in a few days if there are no comments. gdb/ChangeLog: 2014-10-14 Sergio Durigan Junior <sergiodj@redhat.com> * stap-probe.c (stap_parse_argument): Initialize expout explicitly using language_c, instead of current_language. gdb/testsuite/ChangeLog: 2014-10-14 Sergio Durigan Junior <sergiodj@redhat.com> * gdb.arch/stap-eval-lang-ada.S: Likewise. * gdb.arch/stap-eval-lang-ada.c: Likewise. * gdb.arch/stap-eval-lang-ada.exp: New file.
1824 lines
50 KiB
C
1824 lines
50 KiB
C
/* SystemTap probe support for GDB.
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Copyright (C) 2012-2014 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "stap-probe.h"
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#include "probe.h"
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#include "vec.h"
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#include "ui-out.h"
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#include "objfiles.h"
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#include "arch-utils.h"
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#include "command.h"
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#include "gdbcmd.h"
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#include "filenames.h"
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#include "value.h"
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#include "ax.h"
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#include "ax-gdb.h"
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#include "complaints.h"
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#include "cli/cli-utils.h"
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#include "linespec.h"
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#include "user-regs.h"
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#include "parser-defs.h"
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#include "language.h"
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#include "elf-bfd.h"
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#include <ctype.h>
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/* The name of the SystemTap section where we will find information about
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the probes. */
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#define STAP_BASE_SECTION_NAME ".stapsdt.base"
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/* Forward declaration. */
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static const struct probe_ops stap_probe_ops;
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/* Should we display debug information for the probe's argument expression
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parsing? */
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static unsigned int stap_expression_debug = 0;
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/* The various possibilities of bitness defined for a probe's argument.
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The relationship is:
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- STAP_ARG_BITNESS_UNDEFINED: The user hasn't specified the bitness.
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- STAP_ARG_BITNESS_8BIT_UNSIGNED: argument string starts with `1@'.
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- STAP_ARG_BITNESS_8BIT_SIGNED: argument string starts with `-1@'.
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- STAP_ARG_BITNESS_16BIT_UNSIGNED: argument string starts with `2@'.
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- STAP_ARG_BITNESS_16BIT_SIGNED: argument string starts with `-2@'.
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- STAP_ARG_BITNESS_32BIT_UNSIGNED: argument string starts with `4@'.
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- STAP_ARG_BITNESS_32BIT_SIGNED: argument string starts with `-4@'.
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- STAP_ARG_BITNESS_64BIT_UNSIGNED: argument string starts with `8@'.
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- STAP_ARG_BITNESS_64BIT_SIGNED: argument string starts with `-8@'. */
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enum stap_arg_bitness
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{
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STAP_ARG_BITNESS_UNDEFINED,
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STAP_ARG_BITNESS_8BIT_UNSIGNED,
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STAP_ARG_BITNESS_8BIT_SIGNED,
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STAP_ARG_BITNESS_16BIT_UNSIGNED,
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STAP_ARG_BITNESS_16BIT_SIGNED,
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STAP_ARG_BITNESS_32BIT_UNSIGNED,
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STAP_ARG_BITNESS_32BIT_SIGNED,
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STAP_ARG_BITNESS_64BIT_UNSIGNED,
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STAP_ARG_BITNESS_64BIT_SIGNED,
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};
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/* The following structure represents a single argument for the probe. */
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struct stap_probe_arg
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{
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/* The bitness of this argument. */
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enum stap_arg_bitness bitness;
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/* The corresponding `struct type *' to the bitness. */
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struct type *atype;
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/* The argument converted to an internal GDB expression. */
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struct expression *aexpr;
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};
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typedef struct stap_probe_arg stap_probe_arg_s;
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DEF_VEC_O (stap_probe_arg_s);
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struct stap_probe
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{
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/* Generic information about the probe. This shall be the first element
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of this struct, in order to maintain binary compatibility with the
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`struct probe' and be able to fully abstract it. */
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struct probe p;
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/* If the probe has a semaphore associated, then this is the value of
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it, relative to SECT_OFF_DATA. */
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CORE_ADDR sem_addr;
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/* One if the arguments have been parsed. */
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unsigned int args_parsed : 1;
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union
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{
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const char *text;
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/* Information about each argument. This is an array of `stap_probe_arg',
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with each entry representing one argument. */
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VEC (stap_probe_arg_s) *vec;
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}
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args_u;
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};
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/* When parsing the arguments, we have to establish different precedences
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for the various kinds of asm operators. This enumeration represents those
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precedences.
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This logic behind this is available at
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<http://sourceware.org/binutils/docs/as/Infix-Ops.html#Infix-Ops>, or using
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the command "info '(as)Infix Ops'". */
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enum stap_operand_prec
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{
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/* Lowest precedence, used for non-recognized operands or for the beginning
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of the parsing process. */
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STAP_OPERAND_PREC_NONE = 0,
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/* Precedence of logical OR. */
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STAP_OPERAND_PREC_LOGICAL_OR,
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/* Precedence of logical AND. */
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STAP_OPERAND_PREC_LOGICAL_AND,
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/* Precedence of additive (plus, minus) and comparative (equal, less,
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greater-than, etc) operands. */
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STAP_OPERAND_PREC_ADD_CMP,
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/* Precedence of bitwise operands (bitwise OR, XOR, bitwise AND,
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logical NOT). */
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STAP_OPERAND_PREC_BITWISE,
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/* Precedence of multiplicative operands (multiplication, division,
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remainder, left shift and right shift). */
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STAP_OPERAND_PREC_MUL
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};
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static void stap_parse_argument_1 (struct stap_parse_info *p, int has_lhs,
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enum stap_operand_prec prec);
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static void stap_parse_argument_conditionally (struct stap_parse_info *p);
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/* Returns 1 if *S is an operator, zero otherwise. */
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static int stap_is_operator (const char *op);
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static void
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show_stapexpressiondebug (struct ui_file *file, int from_tty,
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struct cmd_list_element *c, const char *value)
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{
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fprintf_filtered (file, _("SystemTap Probe expression debugging is %s.\n"),
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value);
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}
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/* Returns the operator precedence level of OP, or STAP_OPERAND_PREC_NONE
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if the operator code was not recognized. */
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static enum stap_operand_prec
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stap_get_operator_prec (enum exp_opcode op)
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{
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switch (op)
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{
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case BINOP_LOGICAL_OR:
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return STAP_OPERAND_PREC_LOGICAL_OR;
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case BINOP_LOGICAL_AND:
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return STAP_OPERAND_PREC_LOGICAL_AND;
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case BINOP_ADD:
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case BINOP_SUB:
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case BINOP_EQUAL:
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case BINOP_NOTEQUAL:
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case BINOP_LESS:
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case BINOP_LEQ:
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case BINOP_GTR:
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case BINOP_GEQ:
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return STAP_OPERAND_PREC_ADD_CMP;
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case BINOP_BITWISE_IOR:
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case BINOP_BITWISE_AND:
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case BINOP_BITWISE_XOR:
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case UNOP_LOGICAL_NOT:
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return STAP_OPERAND_PREC_BITWISE;
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case BINOP_MUL:
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case BINOP_DIV:
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case BINOP_REM:
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case BINOP_LSH:
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case BINOP_RSH:
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return STAP_OPERAND_PREC_MUL;
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default:
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return STAP_OPERAND_PREC_NONE;
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}
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}
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/* Given S, read the operator in it and fills the OP pointer with its code.
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Return 1 on success, zero if the operator was not recognized. */
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static enum exp_opcode
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stap_get_opcode (const char **s)
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{
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const char c = **s;
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enum exp_opcode op;
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*s += 1;
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switch (c)
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{
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case '*':
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op = BINOP_MUL;
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break;
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case '/':
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op = BINOP_DIV;
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break;
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case '%':
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op = BINOP_REM;
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break;
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case '<':
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op = BINOP_LESS;
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if (**s == '<')
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{
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*s += 1;
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op = BINOP_LSH;
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}
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else if (**s == '=')
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{
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*s += 1;
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op = BINOP_LEQ;
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}
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else if (**s == '>')
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{
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*s += 1;
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op = BINOP_NOTEQUAL;
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}
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break;
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case '>':
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op = BINOP_GTR;
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if (**s == '>')
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{
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*s += 1;
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op = BINOP_RSH;
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}
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else if (**s == '=')
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{
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*s += 1;
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op = BINOP_GEQ;
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}
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break;
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case '|':
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op = BINOP_BITWISE_IOR;
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if (**s == '|')
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{
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*s += 1;
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op = BINOP_LOGICAL_OR;
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}
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break;
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case '&':
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op = BINOP_BITWISE_AND;
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if (**s == '&')
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{
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*s += 1;
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op = BINOP_LOGICAL_AND;
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}
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break;
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case '^':
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op = BINOP_BITWISE_XOR;
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break;
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case '!':
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op = UNOP_LOGICAL_NOT;
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break;
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case '+':
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op = BINOP_ADD;
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break;
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case '-':
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op = BINOP_SUB;
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break;
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case '=':
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gdb_assert (**s == '=');
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op = BINOP_EQUAL;
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break;
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default:
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internal_error (__FILE__, __LINE__,
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_("Invalid opcode in expression `%s' for SystemTap"
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"probe"), *s);
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}
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return op;
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}
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/* Given the bitness of the argument, represented by B, return the
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corresponding `struct type *'. */
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static struct type *
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stap_get_expected_argument_type (struct gdbarch *gdbarch,
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enum stap_arg_bitness b)
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{
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switch (b)
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{
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case STAP_ARG_BITNESS_UNDEFINED:
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if (gdbarch_addr_bit (gdbarch) == 32)
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return builtin_type (gdbarch)->builtin_uint32;
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else
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return builtin_type (gdbarch)->builtin_uint64;
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case STAP_ARG_BITNESS_8BIT_UNSIGNED:
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return builtin_type (gdbarch)->builtin_uint8;
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case STAP_ARG_BITNESS_8BIT_SIGNED:
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return builtin_type (gdbarch)->builtin_int8;
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case STAP_ARG_BITNESS_16BIT_UNSIGNED:
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return builtin_type (gdbarch)->builtin_uint16;
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case STAP_ARG_BITNESS_16BIT_SIGNED:
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return builtin_type (gdbarch)->builtin_int16;
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case STAP_ARG_BITNESS_32BIT_SIGNED:
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return builtin_type (gdbarch)->builtin_int32;
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case STAP_ARG_BITNESS_32BIT_UNSIGNED:
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return builtin_type (gdbarch)->builtin_uint32;
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case STAP_ARG_BITNESS_64BIT_SIGNED:
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return builtin_type (gdbarch)->builtin_int64;
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case STAP_ARG_BITNESS_64BIT_UNSIGNED:
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return builtin_type (gdbarch)->builtin_uint64;
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default:
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internal_error (__FILE__, __LINE__,
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_("Undefined bitness for probe."));
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break;
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}
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}
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/* Helper function to check for a generic list of prefixes. GDBARCH
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is the current gdbarch being used. S is the expression being
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analyzed. If R is not NULL, it will be used to return the found
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prefix. PREFIXES is the list of expected prefixes.
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This function does a case-insensitive match.
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Return 1 if any prefix has been found, zero otherwise. */
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static int
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stap_is_generic_prefix (struct gdbarch *gdbarch, const char *s,
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const char **r, const char *const *prefixes)
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{
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const char *const *p;
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if (prefixes == NULL)
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{
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if (r != NULL)
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*r = "";
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return 1;
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}
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for (p = prefixes; *p != NULL; ++p)
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if (strncasecmp (s, *p, strlen (*p)) == 0)
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{
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if (r != NULL)
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*r = *p;
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return 1;
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}
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return 0;
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}
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/* Return 1 if S points to a register prefix, zero otherwise. For a
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description of the arguments, look at stap_is_generic_prefix. */
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static int
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stap_is_register_prefix (struct gdbarch *gdbarch, const char *s,
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const char **r)
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{
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const char *const *t = gdbarch_stap_register_prefixes (gdbarch);
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return stap_is_generic_prefix (gdbarch, s, r, t);
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}
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/* Return 1 if S points to a register indirection prefix, zero
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otherwise. For a description of the arguments, look at
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stap_is_generic_prefix. */
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static int
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stap_is_register_indirection_prefix (struct gdbarch *gdbarch, const char *s,
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const char **r)
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{
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const char *const *t = gdbarch_stap_register_indirection_prefixes (gdbarch);
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return stap_is_generic_prefix (gdbarch, s, r, t);
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}
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/* Return 1 if S points to an integer prefix, zero otherwise. For a
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description of the arguments, look at stap_is_generic_prefix.
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This function takes care of analyzing whether we are dealing with
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an expected integer prefix, or, if there is no integer prefix to be
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expected, whether we are dealing with a digit. It does a
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case-insensitive match. */
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static int
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stap_is_integer_prefix (struct gdbarch *gdbarch, const char *s,
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const char **r)
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{
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const char *const *t = gdbarch_stap_integer_prefixes (gdbarch);
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const char *const *p;
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if (t == NULL)
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{
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/* A NULL value here means that integers do not have a prefix.
|
||
We just check for a digit then. */
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if (r != NULL)
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*r = "";
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return isdigit (*s);
|
||
}
|
||
|
||
for (p = t; *p != NULL; ++p)
|
||
{
|
||
size_t len = strlen (*p);
|
||
|
||
if ((len == 0 && isdigit (*s))
|
||
|| (len > 0 && strncasecmp (s, *p, len) == 0))
|
||
{
|
||
/* Integers may or may not have a prefix. The "len == 0"
|
||
check covers the case when integers do not have a prefix
|
||
(therefore, we just check if we have a digit). The call
|
||
to "strncasecmp" covers the case when they have a
|
||
prefix. */
|
||
if (r != NULL)
|
||
*r = *p;
|
||
|
||
return 1;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Helper function to check for a generic list of suffixes. If we are
|
||
not expecting any suffixes, then it just returns 1. If we are
|
||
expecting at least one suffix, then it returns 1 if a suffix has
|
||
been found, zero otherwise. GDBARCH is the current gdbarch being
|
||
used. S is the expression being analyzed. If R is not NULL, it
|
||
will be used to return the found suffix. SUFFIXES is the list of
|
||
expected suffixes. This function does a case-insensitive
|
||
match. */
|
||
|
||
static int
|
||
stap_generic_check_suffix (struct gdbarch *gdbarch, const char *s,
|
||
const char **r, const char *const *suffixes)
|
||
{
|
||
const char *const *p;
|
||
int found = 0;
|
||
|
||
if (suffixes == NULL)
|
||
{
|
||
if (r != NULL)
|
||
*r = "";
|
||
|
||
return 1;
|
||
}
|
||
|
||
for (p = suffixes; *p != NULL; ++p)
|
||
if (strncasecmp (s, *p, strlen (*p)) == 0)
|
||
{
|
||
if (r != NULL)
|
||
*r = *p;
|
||
|
||
found = 1;
|
||
break;
|
||
}
|
||
|
||
return found;
|
||
}
|
||
|
||
/* Return 1 if S points to an integer suffix, zero otherwise. For a
|
||
description of the arguments, look at
|
||
stap_generic_check_suffix. */
|
||
|
||
static int
|
||
stap_check_integer_suffix (struct gdbarch *gdbarch, const char *s,
|
||
const char **r)
|
||
{
|
||
const char *const *p = gdbarch_stap_integer_suffixes (gdbarch);
|
||
|
||
return stap_generic_check_suffix (gdbarch, s, r, p);
|
||
}
|
||
|
||
/* Return 1 if S points to a register suffix, zero otherwise. For a
|
||
description of the arguments, look at
|
||
stap_generic_check_suffix. */
|
||
|
||
static int
|
||
stap_check_register_suffix (struct gdbarch *gdbarch, const char *s,
|
||
const char **r)
|
||
{
|
||
const char *const *p = gdbarch_stap_register_suffixes (gdbarch);
|
||
|
||
return stap_generic_check_suffix (gdbarch, s, r, p);
|
||
}
|
||
|
||
/* Return 1 if S points to a register indirection suffix, zero
|
||
otherwise. For a description of the arguments, look at
|
||
stap_generic_check_suffix. */
|
||
|
||
static int
|
||
stap_check_register_indirection_suffix (struct gdbarch *gdbarch, const char *s,
|
||
const char **r)
|
||
{
|
||
const char *const *p = gdbarch_stap_register_indirection_suffixes (gdbarch);
|
||
|
||
return stap_generic_check_suffix (gdbarch, s, r, p);
|
||
}
|
||
|
||
/* Function responsible for parsing a register operand according to
|
||
SystemTap parlance. Assuming:
|
||
|
||
RP = register prefix
|
||
RS = register suffix
|
||
RIP = register indirection prefix
|
||
RIS = register indirection suffix
|
||
|
||
Then a register operand can be:
|
||
|
||
[RIP] [RP] REGISTER [RS] [RIS]
|
||
|
||
This function takes care of a register's indirection, displacement and
|
||
direct access. It also takes into consideration the fact that some
|
||
registers are named differently inside and outside GDB, e.g., PPC's
|
||
general-purpose registers are represented by integers in the assembly
|
||
language (e.g., `15' is the 15th general-purpose register), but inside
|
||
GDB they have a prefix (the letter `r') appended. */
|
||
|
||
static void
|
||
stap_parse_register_operand (struct stap_parse_info *p)
|
||
{
|
||
/* Simple flag to indicate whether we have seen a minus signal before
|
||
certain number. */
|
||
int got_minus = 0;
|
||
/* Flags to indicate whether this register access is being displaced and/or
|
||
indirected. */
|
||
int disp_p = 0, indirect_p = 0;
|
||
struct gdbarch *gdbarch = p->gdbarch;
|
||
/* Needed to generate the register name as a part of an expression. */
|
||
struct stoken str;
|
||
/* Variables used to extract the register name from the probe's
|
||
argument. */
|
||
const char *start;
|
||
char *regname;
|
||
int len;
|
||
const char *gdb_reg_prefix = gdbarch_stap_gdb_register_prefix (gdbarch);
|
||
int gdb_reg_prefix_len = gdb_reg_prefix ? strlen (gdb_reg_prefix) : 0;
|
||
const char *gdb_reg_suffix = gdbarch_stap_gdb_register_suffix (gdbarch);
|
||
int gdb_reg_suffix_len = gdb_reg_suffix ? strlen (gdb_reg_suffix) : 0;
|
||
const char *reg_prefix;
|
||
const char *reg_ind_prefix;
|
||
const char *reg_suffix;
|
||
const char *reg_ind_suffix;
|
||
|
||
/* Checking for a displacement argument. */
|
||
if (*p->arg == '+')
|
||
{
|
||
/* If it's a plus sign, we don't need to do anything, just advance the
|
||
pointer. */
|
||
++p->arg;
|
||
}
|
||
|
||
if (*p->arg == '-')
|
||
{
|
||
got_minus = 1;
|
||
++p->arg;
|
||
}
|
||
|
||
if (isdigit (*p->arg))
|
||
{
|
||
/* The value of the displacement. */
|
||
long displacement;
|
||
char *endp;
|
||
|
||
disp_p = 1;
|
||
displacement = strtol (p->arg, &endp, 10);
|
||
p->arg = endp;
|
||
|
||
/* Generating the expression for the displacement. */
|
||
write_exp_elt_opcode (&p->pstate, OP_LONG);
|
||
write_exp_elt_type (&p->pstate, builtin_type (gdbarch)->builtin_long);
|
||
write_exp_elt_longcst (&p->pstate, displacement);
|
||
write_exp_elt_opcode (&p->pstate, OP_LONG);
|
||
if (got_minus)
|
||
write_exp_elt_opcode (&p->pstate, UNOP_NEG);
|
||
}
|
||
|
||
/* Getting rid of register indirection prefix. */
|
||
if (stap_is_register_indirection_prefix (gdbarch, p->arg, ®_ind_prefix))
|
||
{
|
||
indirect_p = 1;
|
||
p->arg += strlen (reg_ind_prefix);
|
||
}
|
||
|
||
if (disp_p && !indirect_p)
|
||
error (_("Invalid register displacement syntax on expression `%s'."),
|
||
p->saved_arg);
|
||
|
||
/* Getting rid of register prefix. */
|
||
if (stap_is_register_prefix (gdbarch, p->arg, ®_prefix))
|
||
p->arg += strlen (reg_prefix);
|
||
|
||
/* Now we should have only the register name. Let's extract it and get
|
||
the associated number. */
|
||
start = p->arg;
|
||
|
||
/* We assume the register name is composed by letters and numbers. */
|
||
while (isalnum (*p->arg))
|
||
++p->arg;
|
||
|
||
len = p->arg - start;
|
||
|
||
regname = alloca (len + gdb_reg_prefix_len + gdb_reg_suffix_len + 1);
|
||
regname[0] = '\0';
|
||
|
||
/* We only add the GDB's register prefix/suffix if we are dealing with
|
||
a numeric register. */
|
||
if (gdb_reg_prefix && isdigit (*start))
|
||
{
|
||
strncpy (regname, gdb_reg_prefix, gdb_reg_prefix_len);
|
||
strncpy (regname + gdb_reg_prefix_len, start, len);
|
||
|
||
if (gdb_reg_suffix)
|
||
strncpy (regname + gdb_reg_prefix_len + len,
|
||
gdb_reg_suffix, gdb_reg_suffix_len);
|
||
|
||
len += gdb_reg_prefix_len + gdb_reg_suffix_len;
|
||
}
|
||
else
|
||
strncpy (regname, start, len);
|
||
|
||
regname[len] = '\0';
|
||
|
||
/* Is this a valid register name? */
|
||
if (user_reg_map_name_to_regnum (gdbarch, regname, len) == -1)
|
||
error (_("Invalid register name `%s' on expression `%s'."),
|
||
regname, p->saved_arg);
|
||
|
||
write_exp_elt_opcode (&p->pstate, OP_REGISTER);
|
||
str.ptr = regname;
|
||
str.length = len;
|
||
write_exp_string (&p->pstate, str);
|
||
write_exp_elt_opcode (&p->pstate, OP_REGISTER);
|
||
|
||
if (indirect_p)
|
||
{
|
||
if (disp_p)
|
||
write_exp_elt_opcode (&p->pstate, BINOP_ADD);
|
||
|
||
/* Casting to the expected type. */
|
||
write_exp_elt_opcode (&p->pstate, UNOP_CAST);
|
||
write_exp_elt_type (&p->pstate, lookup_pointer_type (p->arg_type));
|
||
write_exp_elt_opcode (&p->pstate, UNOP_CAST);
|
||
|
||
write_exp_elt_opcode (&p->pstate, UNOP_IND);
|
||
}
|
||
|
||
/* Getting rid of the register name suffix. */
|
||
if (stap_check_register_suffix (gdbarch, p->arg, ®_suffix))
|
||
p->arg += strlen (reg_suffix);
|
||
else
|
||
error (_("Missing register name suffix on expression `%s'."),
|
||
p->saved_arg);
|
||
|
||
/* Getting rid of the register indirection suffix. */
|
||
if (indirect_p)
|
||
{
|
||
if (stap_check_register_indirection_suffix (gdbarch, p->arg,
|
||
®_ind_suffix))
|
||
p->arg += strlen (reg_ind_suffix);
|
||
else
|
||
error (_("Missing indirection suffix on expression `%s'."),
|
||
p->saved_arg);
|
||
}
|
||
}
|
||
|
||
/* This function is responsible for parsing a single operand.
|
||
|
||
A single operand can be:
|
||
|
||
- an unary operation (e.g., `-5', `~2', or even with subexpressions
|
||
like `-(2 + 1)')
|
||
- a register displacement, which will be treated as a register
|
||
operand (e.g., `-4(%eax)' on x86)
|
||
- a numeric constant, or
|
||
- a register operand (see function `stap_parse_register_operand')
|
||
|
||
The function also calls special-handling functions to deal with
|
||
unrecognized operands, allowing arch-specific parsers to be
|
||
created. */
|
||
|
||
static void
|
||
stap_parse_single_operand (struct stap_parse_info *p)
|
||
{
|
||
struct gdbarch *gdbarch = p->gdbarch;
|
||
const char *int_prefix = NULL;
|
||
|
||
/* We first try to parse this token as a "special token". */
|
||
if (gdbarch_stap_parse_special_token_p (gdbarch))
|
||
if (gdbarch_stap_parse_special_token (gdbarch, p) != 0)
|
||
{
|
||
/* If the return value of the above function is not zero,
|
||
it means it successfully parsed the special token.
|
||
|
||
If it is NULL, we try to parse it using our method. */
|
||
return;
|
||
}
|
||
|
||
if (*p->arg == '-' || *p->arg == '~' || *p->arg == '+')
|
||
{
|
||
char c = *p->arg;
|
||
/* We use this variable to do a lookahead. */
|
||
const char *tmp = p->arg;
|
||
int has_digit = 0;
|
||
|
||
/* Skipping signal. */
|
||
++tmp;
|
||
|
||
/* This is an unary operation. Here is a list of allowed tokens
|
||
here:
|
||
|
||
- numeric literal;
|
||
- number (from register displacement)
|
||
- subexpression (beginning with `(')
|
||
|
||
We handle the register displacement here, and the other cases
|
||
recursively. */
|
||
if (p->inside_paren_p)
|
||
tmp = skip_spaces_const (tmp);
|
||
|
||
while (isdigit (*tmp))
|
||
{
|
||
/* We skip the digit here because we are only interested in
|
||
knowing what kind of unary operation this is. The digit
|
||
will be handled by one of the functions that will be
|
||
called below ('stap_parse_argument_conditionally' or
|
||
'stap_parse_register_operand'). */
|
||
++tmp;
|
||
has_digit = 1;
|
||
}
|
||
|
||
if (has_digit && stap_is_register_indirection_prefix (gdbarch, tmp,
|
||
NULL))
|
||
{
|
||
/* If we are here, it means it is a displacement. The only
|
||
operations allowed here are `-' and `+'. */
|
||
if (c == '~')
|
||
error (_("Invalid operator `%c' for register displacement "
|
||
"on expression `%s'."), c, p->saved_arg);
|
||
|
||
stap_parse_register_operand (p);
|
||
}
|
||
else
|
||
{
|
||
/* This is not a displacement. We skip the operator, and
|
||
deal with it when the recursion returns. */
|
||
++p->arg;
|
||
stap_parse_argument_conditionally (p);
|
||
if (c == '-')
|
||
write_exp_elt_opcode (&p->pstate, UNOP_NEG);
|
||
else if (c == '~')
|
||
write_exp_elt_opcode (&p->pstate, UNOP_COMPLEMENT);
|
||
}
|
||
}
|
||
else if (isdigit (*p->arg))
|
||
{
|
||
/* A temporary variable, needed for lookahead. */
|
||
const char *tmp = p->arg;
|
||
char *endp;
|
||
long number;
|
||
|
||
/* We can be dealing with a numeric constant, or with a register
|
||
displacement. */
|
||
number = strtol (tmp, &endp, 10);
|
||
tmp = endp;
|
||
|
||
if (p->inside_paren_p)
|
||
tmp = skip_spaces_const (tmp);
|
||
|
||
/* If "stap_is_integer_prefix" returns true, it means we can
|
||
accept integers without a prefix here. But we also need to
|
||
check whether the next token (i.e., "tmp") is not a register
|
||
indirection prefix. */
|
||
if (stap_is_integer_prefix (gdbarch, p->arg, NULL)
|
||
&& !stap_is_register_indirection_prefix (gdbarch, tmp, NULL))
|
||
{
|
||
const char *int_suffix;
|
||
|
||
/* We are dealing with a numeric constant. */
|
||
write_exp_elt_opcode (&p->pstate, OP_LONG);
|
||
write_exp_elt_type (&p->pstate,
|
||
builtin_type (gdbarch)->builtin_long);
|
||
write_exp_elt_longcst (&p->pstate, number);
|
||
write_exp_elt_opcode (&p->pstate, OP_LONG);
|
||
|
||
p->arg = tmp;
|
||
|
||
if (stap_check_integer_suffix (gdbarch, p->arg, &int_suffix))
|
||
p->arg += strlen (int_suffix);
|
||
else
|
||
error (_("Invalid constant suffix on expression `%s'."),
|
||
p->saved_arg);
|
||
}
|
||
else if (stap_is_register_indirection_prefix (gdbarch, tmp, NULL))
|
||
stap_parse_register_operand (p);
|
||
else
|
||
error (_("Unknown numeric token on expression `%s'."),
|
||
p->saved_arg);
|
||
}
|
||
else if (stap_is_integer_prefix (gdbarch, p->arg, &int_prefix))
|
||
{
|
||
/* We are dealing with a numeric constant. */
|
||
long number;
|
||
char *endp;
|
||
const char *int_suffix;
|
||
|
||
p->arg += strlen (int_prefix);
|
||
number = strtol (p->arg, &endp, 10);
|
||
p->arg = endp;
|
||
|
||
write_exp_elt_opcode (&p->pstate, OP_LONG);
|
||
write_exp_elt_type (&p->pstate, builtin_type (gdbarch)->builtin_long);
|
||
write_exp_elt_longcst (&p->pstate, number);
|
||
write_exp_elt_opcode (&p->pstate, OP_LONG);
|
||
|
||
if (stap_check_integer_suffix (gdbarch, p->arg, &int_suffix))
|
||
p->arg += strlen (int_suffix);
|
||
else
|
||
error (_("Invalid constant suffix on expression `%s'."),
|
||
p->saved_arg);
|
||
}
|
||
else if (stap_is_register_prefix (gdbarch, p->arg, NULL)
|
||
|| stap_is_register_indirection_prefix (gdbarch, p->arg, NULL))
|
||
stap_parse_register_operand (p);
|
||
else
|
||
error (_("Operator `%c' not recognized on expression `%s'."),
|
||
*p->arg, p->saved_arg);
|
||
}
|
||
|
||
/* This function parses an argument conditionally, based on single or
|
||
non-single operands. A non-single operand would be a parenthesized
|
||
expression (e.g., `(2 + 1)'), and a single operand is anything that
|
||
starts with `-', `~', `+' (i.e., unary operators), a digit, or
|
||
something recognized by `gdbarch_stap_is_single_operand'. */
|
||
|
||
static void
|
||
stap_parse_argument_conditionally (struct stap_parse_info *p)
|
||
{
|
||
gdb_assert (gdbarch_stap_is_single_operand_p (p->gdbarch));
|
||
|
||
if (*p->arg == '-' || *p->arg == '~' || *p->arg == '+' /* Unary. */
|
||
|| isdigit (*p->arg)
|
||
|| gdbarch_stap_is_single_operand (p->gdbarch, p->arg))
|
||
stap_parse_single_operand (p);
|
||
else if (*p->arg == '(')
|
||
{
|
||
/* We are dealing with a parenthesized operand. It means we
|
||
have to parse it as it was a separate expression, without
|
||
left-side or precedence. */
|
||
++p->arg;
|
||
p->arg = skip_spaces_const (p->arg);
|
||
++p->inside_paren_p;
|
||
|
||
stap_parse_argument_1 (p, 0, STAP_OPERAND_PREC_NONE);
|
||
|
||
--p->inside_paren_p;
|
||
if (*p->arg != ')')
|
||
error (_("Missign close-paren on expression `%s'."),
|
||
p->saved_arg);
|
||
|
||
++p->arg;
|
||
if (p->inside_paren_p)
|
||
p->arg = skip_spaces_const (p->arg);
|
||
}
|
||
else
|
||
error (_("Cannot parse expression `%s'."), p->saved_arg);
|
||
}
|
||
|
||
/* Helper function for `stap_parse_argument'. Please, see its comments to
|
||
better understand what this function does. */
|
||
|
||
static void
|
||
stap_parse_argument_1 (struct stap_parse_info *p, int has_lhs,
|
||
enum stap_operand_prec prec)
|
||
{
|
||
/* This is an operator-precedence parser.
|
||
|
||
We work with left- and right-sides of expressions, and
|
||
parse them depending on the precedence of the operators
|
||
we find. */
|
||
|
||
gdb_assert (p->arg != NULL);
|
||
|
||
if (p->inside_paren_p)
|
||
p->arg = skip_spaces_const (p->arg);
|
||
|
||
if (!has_lhs)
|
||
{
|
||
/* We were called without a left-side, either because this is the
|
||
first call, or because we were called to parse a parenthesized
|
||
expression. It doesn't really matter; we have to parse the
|
||
left-side in order to continue the process. */
|
||
stap_parse_argument_conditionally (p);
|
||
}
|
||
|
||
/* Start to parse the right-side, and to "join" left and right sides
|
||
depending on the operation specified.
|
||
|
||
This loop shall continue until we run out of characters in the input,
|
||
or until we find a close-parenthesis, which means that we've reached
|
||
the end of a sub-expression. */
|
||
while (*p->arg != '\0' && *p->arg != ')' && !isspace (*p->arg))
|
||
{
|
||
const char *tmp_exp_buf;
|
||
enum exp_opcode opcode;
|
||
enum stap_operand_prec cur_prec;
|
||
|
||
if (!stap_is_operator (p->arg))
|
||
error (_("Invalid operator `%c' on expression `%s'."), *p->arg,
|
||
p->saved_arg);
|
||
|
||
/* We have to save the current value of the expression buffer because
|
||
the `stap_get_opcode' modifies it in order to get the current
|
||
operator. If this operator's precedence is lower than PREC, we
|
||
should return and not advance the expression buffer pointer. */
|
||
tmp_exp_buf = p->arg;
|
||
opcode = stap_get_opcode (&tmp_exp_buf);
|
||
|
||
cur_prec = stap_get_operator_prec (opcode);
|
||
if (cur_prec < prec)
|
||
{
|
||
/* If the precedence of the operator that we are seeing now is
|
||
lower than the precedence of the first operator seen before
|
||
this parsing process began, it means we should stop parsing
|
||
and return. */
|
||
break;
|
||
}
|
||
|
||
p->arg = tmp_exp_buf;
|
||
if (p->inside_paren_p)
|
||
p->arg = skip_spaces_const (p->arg);
|
||
|
||
/* Parse the right-side of the expression. */
|
||
stap_parse_argument_conditionally (p);
|
||
|
||
/* While we still have operators, try to parse another
|
||
right-side, but using the current right-side as a left-side. */
|
||
while (*p->arg != '\0' && stap_is_operator (p->arg))
|
||
{
|
||
enum exp_opcode lookahead_opcode;
|
||
enum stap_operand_prec lookahead_prec;
|
||
|
||
/* Saving the current expression buffer position. The explanation
|
||
is the same as above. */
|
||
tmp_exp_buf = p->arg;
|
||
lookahead_opcode = stap_get_opcode (&tmp_exp_buf);
|
||
lookahead_prec = stap_get_operator_prec (lookahead_opcode);
|
||
|
||
if (lookahead_prec <= prec)
|
||
{
|
||
/* If we are dealing with an operator whose precedence is lower
|
||
than the first one, just abandon the attempt. */
|
||
break;
|
||
}
|
||
|
||
/* Parse the right-side of the expression, but since we already
|
||
have a left-side at this point, set `has_lhs' to 1. */
|
||
stap_parse_argument_1 (p, 1, lookahead_prec);
|
||
}
|
||
|
||
write_exp_elt_opcode (&p->pstate, opcode);
|
||
}
|
||
}
|
||
|
||
/* Parse a probe's argument.
|
||
|
||
Assuming that:
|
||
|
||
LP = literal integer prefix
|
||
LS = literal integer suffix
|
||
|
||
RP = register prefix
|
||
RS = register suffix
|
||
|
||
RIP = register indirection prefix
|
||
RIS = register indirection suffix
|
||
|
||
This routine assumes that arguments' tokens are of the form:
|
||
|
||
- [LP] NUMBER [LS]
|
||
- [RP] REGISTER [RS]
|
||
- [RIP] [RP] REGISTER [RS] [RIS]
|
||
- If we find a number without LP, we try to parse it as a literal integer
|
||
constant (if LP == NULL), or as a register displacement.
|
||
- We count parenthesis, and only skip whitespaces if we are inside them.
|
||
- If we find an operator, we skip it.
|
||
|
||
This function can also call a special function that will try to match
|
||
unknown tokens. It will return 1 if the argument has been parsed
|
||
successfully, or zero otherwise. */
|
||
|
||
static struct expression *
|
||
stap_parse_argument (const char **arg, struct type *atype,
|
||
struct gdbarch *gdbarch)
|
||
{
|
||
struct stap_parse_info p;
|
||
struct cleanup *back_to;
|
||
|
||
/* We need to initialize the expression buffer, in order to begin
|
||
our parsing efforts. We use language_c here because we may need
|
||
to do pointer arithmetics. */
|
||
initialize_expout (&p.pstate, 10, language_def (language_c), gdbarch);
|
||
back_to = make_cleanup (free_current_contents, &p.pstate.expout);
|
||
|
||
p.saved_arg = *arg;
|
||
p.arg = *arg;
|
||
p.arg_type = atype;
|
||
p.gdbarch = gdbarch;
|
||
p.inside_paren_p = 0;
|
||
|
||
stap_parse_argument_1 (&p, 0, STAP_OPERAND_PREC_NONE);
|
||
|
||
discard_cleanups (back_to);
|
||
|
||
gdb_assert (p.inside_paren_p == 0);
|
||
|
||
/* Casting the final expression to the appropriate type. */
|
||
write_exp_elt_opcode (&p.pstate, UNOP_CAST);
|
||
write_exp_elt_type (&p.pstate, atype);
|
||
write_exp_elt_opcode (&p.pstate, UNOP_CAST);
|
||
|
||
reallocate_expout (&p.pstate);
|
||
|
||
p.arg = skip_spaces_const (p.arg);
|
||
*arg = p.arg;
|
||
|
||
/* We can safely return EXPOUT here. */
|
||
return p.pstate.expout;
|
||
}
|
||
|
||
/* Function which parses an argument string from PROBE, correctly splitting
|
||
the arguments and storing their information in properly ways.
|
||
|
||
Consider the following argument string (x86 syntax):
|
||
|
||
`4@%eax 4@$10'
|
||
|
||
We have two arguments, `%eax' and `$10', both with 32-bit unsigned bitness.
|
||
This function basically handles them, properly filling some structures with
|
||
this information. */
|
||
|
||
static void
|
||
stap_parse_probe_arguments (struct stap_probe *probe, struct gdbarch *gdbarch)
|
||
{
|
||
const char *cur;
|
||
|
||
gdb_assert (!probe->args_parsed);
|
||
cur = probe->args_u.text;
|
||
probe->args_parsed = 1;
|
||
probe->args_u.vec = NULL;
|
||
|
||
if (cur == NULL || *cur == '\0' || *cur == ':')
|
||
return;
|
||
|
||
while (*cur != '\0')
|
||
{
|
||
struct stap_probe_arg arg;
|
||
enum stap_arg_bitness b;
|
||
int got_minus = 0;
|
||
struct expression *expr;
|
||
|
||
memset (&arg, 0, sizeof (arg));
|
||
|
||
/* We expect to find something like:
|
||
|
||
N@OP
|
||
|
||
Where `N' can be [+,-][1,2,4,8]. This is not mandatory, so
|
||
we check it here. If we don't find it, go to the next
|
||
state. */
|
||
if ((cur[0] == '-' && isdigit (cur[1]) && cur[2] == '@')
|
||
|| (isdigit (cur[0]) && cur[1] == '@'))
|
||
{
|
||
if (*cur == '-')
|
||
{
|
||
/* Discard the `-'. */
|
||
++cur;
|
||
got_minus = 1;
|
||
}
|
||
|
||
/* Defining the bitness. */
|
||
switch (*cur)
|
||
{
|
||
case '1':
|
||
b = (got_minus ? STAP_ARG_BITNESS_8BIT_SIGNED
|
||
: STAP_ARG_BITNESS_8BIT_UNSIGNED);
|
||
break;
|
||
|
||
case '2':
|
||
b = (got_minus ? STAP_ARG_BITNESS_16BIT_SIGNED
|
||
: STAP_ARG_BITNESS_16BIT_UNSIGNED);
|
||
break;
|
||
|
||
case '4':
|
||
b = (got_minus ? STAP_ARG_BITNESS_32BIT_SIGNED
|
||
: STAP_ARG_BITNESS_32BIT_UNSIGNED);
|
||
break;
|
||
|
||
case '8':
|
||
b = (got_minus ? STAP_ARG_BITNESS_64BIT_SIGNED
|
||
: STAP_ARG_BITNESS_64BIT_UNSIGNED);
|
||
break;
|
||
|
||
default:
|
||
{
|
||
/* We have an error, because we don't expect anything
|
||
except 1, 2, 4 and 8. */
|
||
warning (_("unrecognized bitness %s%c' for probe `%s'"),
|
||
got_minus ? "`-" : "`", *cur, probe->p.name);
|
||
return;
|
||
}
|
||
}
|
||
|
||
arg.bitness = b;
|
||
|
||
/* Discard the number and the `@' sign. */
|
||
cur += 2;
|
||
}
|
||
else
|
||
arg.bitness = STAP_ARG_BITNESS_UNDEFINED;
|
||
|
||
arg.atype = stap_get_expected_argument_type (gdbarch, arg.bitness);
|
||
|
||
expr = stap_parse_argument (&cur, arg.atype, gdbarch);
|
||
|
||
if (stap_expression_debug)
|
||
dump_raw_expression (expr, gdb_stdlog,
|
||
"before conversion to prefix form");
|
||
|
||
prefixify_expression (expr);
|
||
|
||
if (stap_expression_debug)
|
||
dump_prefix_expression (expr, gdb_stdlog);
|
||
|
||
arg.aexpr = expr;
|
||
|
||
/* Start it over again. */
|
||
cur = skip_spaces_const (cur);
|
||
|
||
VEC_safe_push (stap_probe_arg_s, probe->args_u.vec, &arg);
|
||
}
|
||
}
|
||
|
||
/* Implementation of the get_probe_address method. */
|
||
|
||
static CORE_ADDR
|
||
stap_get_probe_address (struct probe *probe, struct objfile *objfile)
|
||
{
|
||
return probe->address + ANOFFSET (objfile->section_offsets,
|
||
SECT_OFF_DATA (objfile));
|
||
}
|
||
|
||
/* Given PROBE, returns the number of arguments present in that probe's
|
||
argument string. */
|
||
|
||
static unsigned
|
||
stap_get_probe_argument_count (struct probe *probe_generic,
|
||
struct frame_info *frame)
|
||
{
|
||
struct stap_probe *probe = (struct stap_probe *) probe_generic;
|
||
struct gdbarch *gdbarch = get_frame_arch (frame);
|
||
|
||
gdb_assert (probe_generic->pops == &stap_probe_ops);
|
||
|
||
if (!probe->args_parsed)
|
||
{
|
||
if (can_evaluate_probe_arguments (probe_generic))
|
||
stap_parse_probe_arguments (probe, gdbarch);
|
||
else
|
||
{
|
||
static int have_warned_stap_incomplete = 0;
|
||
|
||
if (!have_warned_stap_incomplete)
|
||
{
|
||
warning (_(
|
||
"The SystemTap SDT probe support is not fully implemented on this target;\n"
|
||
"you will not be able to inspect the arguments of the probes.\n"
|
||
"Please report a bug against GDB requesting a port to this target."));
|
||
have_warned_stap_incomplete = 1;
|
||
}
|
||
|
||
/* Marking the arguments as "already parsed". */
|
||
probe->args_u.vec = NULL;
|
||
probe->args_parsed = 1;
|
||
}
|
||
}
|
||
|
||
gdb_assert (probe->args_parsed);
|
||
return VEC_length (stap_probe_arg_s, probe->args_u.vec);
|
||
}
|
||
|
||
/* Return 1 if OP is a valid operator inside a probe argument, or zero
|
||
otherwise. */
|
||
|
||
static int
|
||
stap_is_operator (const char *op)
|
||
{
|
||
int ret = 1;
|
||
|
||
switch (*op)
|
||
{
|
||
case '*':
|
||
case '/':
|
||
case '%':
|
||
case '^':
|
||
case '!':
|
||
case '+':
|
||
case '-':
|
||
case '<':
|
||
case '>':
|
||
case '|':
|
||
case '&':
|
||
break;
|
||
|
||
case '=':
|
||
if (op[1] != '=')
|
||
ret = 0;
|
||
break;
|
||
|
||
default:
|
||
/* We didn't find any operator. */
|
||
ret = 0;
|
||
}
|
||
|
||
return ret;
|
||
}
|
||
|
||
static struct stap_probe_arg *
|
||
stap_get_arg (struct stap_probe *probe, unsigned n, struct gdbarch *gdbarch)
|
||
{
|
||
if (!probe->args_parsed)
|
||
stap_parse_probe_arguments (probe, gdbarch);
|
||
|
||
return VEC_index (stap_probe_arg_s, probe->args_u.vec, n);
|
||
}
|
||
|
||
/* Implement the `can_evaluate_probe_arguments' method of probe_ops. */
|
||
|
||
static int
|
||
stap_can_evaluate_probe_arguments (struct probe *probe_generic)
|
||
{
|
||
struct stap_probe *stap_probe = (struct stap_probe *) probe_generic;
|
||
struct gdbarch *gdbarch = stap_probe->p.arch;
|
||
|
||
/* For SystemTap probes, we have to guarantee that the method
|
||
stap_is_single_operand is defined on gdbarch. If it is not, then it
|
||
means that argument evaluation is not implemented on this target. */
|
||
return gdbarch_stap_is_single_operand_p (gdbarch);
|
||
}
|
||
|
||
/* Evaluate the probe's argument N (indexed from 0), returning a value
|
||
corresponding to it. Assertion is thrown if N does not exist. */
|
||
|
||
static struct value *
|
||
stap_evaluate_probe_argument (struct probe *probe_generic, unsigned n,
|
||
struct frame_info *frame)
|
||
{
|
||
struct stap_probe *stap_probe = (struct stap_probe *) probe_generic;
|
||
struct gdbarch *gdbarch = get_frame_arch (frame);
|
||
struct stap_probe_arg *arg;
|
||
int pos = 0;
|
||
|
||
gdb_assert (probe_generic->pops == &stap_probe_ops);
|
||
|
||
arg = stap_get_arg (stap_probe, n, gdbarch);
|
||
return evaluate_subexp_standard (arg->atype, arg->aexpr, &pos, EVAL_NORMAL);
|
||
}
|
||
|
||
/* Compile the probe's argument N (indexed from 0) to agent expression.
|
||
Assertion is thrown if N does not exist. */
|
||
|
||
static void
|
||
stap_compile_to_ax (struct probe *probe_generic, struct agent_expr *expr,
|
||
struct axs_value *value, unsigned n)
|
||
{
|
||
struct stap_probe *stap_probe = (struct stap_probe *) probe_generic;
|
||
struct stap_probe_arg *arg;
|
||
union exp_element *pc;
|
||
|
||
gdb_assert (probe_generic->pops == &stap_probe_ops);
|
||
|
||
arg = stap_get_arg (stap_probe, n, expr->gdbarch);
|
||
|
||
pc = arg->aexpr->elts;
|
||
gen_expr (arg->aexpr, &pc, expr, value);
|
||
|
||
require_rvalue (expr, value);
|
||
value->type = arg->atype;
|
||
}
|
||
|
||
/* Destroy (free) the data related to PROBE. PROBE memory itself is not feed
|
||
as it is allocated on an obstack. */
|
||
|
||
static void
|
||
stap_probe_destroy (struct probe *probe_generic)
|
||
{
|
||
struct stap_probe *probe = (struct stap_probe *) probe_generic;
|
||
|
||
gdb_assert (probe_generic->pops == &stap_probe_ops);
|
||
|
||
if (probe->args_parsed)
|
||
{
|
||
struct stap_probe_arg *arg;
|
||
int ix;
|
||
|
||
for (ix = 0; VEC_iterate (stap_probe_arg_s, probe->args_u.vec, ix, arg);
|
||
++ix)
|
||
xfree (arg->aexpr);
|
||
VEC_free (stap_probe_arg_s, probe->args_u.vec);
|
||
}
|
||
}
|
||
|
||
|
||
|
||
/* This is called to compute the value of one of the $_probe_arg*
|
||
convenience variables. */
|
||
|
||
static struct value *
|
||
compute_probe_arg (struct gdbarch *arch, struct internalvar *ivar,
|
||
void *data)
|
||
{
|
||
struct frame_info *frame = get_selected_frame (_("No frame selected"));
|
||
CORE_ADDR pc = get_frame_pc (frame);
|
||
int sel = (int) (uintptr_t) data;
|
||
struct bound_probe pc_probe;
|
||
const struct sym_probe_fns *pc_probe_fns;
|
||
unsigned n_args;
|
||
|
||
/* SEL == -1 means "_probe_argc". */
|
||
gdb_assert (sel >= -1);
|
||
|
||
pc_probe = find_probe_by_pc (pc);
|
||
if (pc_probe.probe == NULL)
|
||
error (_("No SystemTap probe at PC %s"), core_addr_to_string (pc));
|
||
|
||
n_args = get_probe_argument_count (pc_probe.probe, frame);
|
||
if (sel == -1)
|
||
return value_from_longest (builtin_type (arch)->builtin_int, n_args);
|
||
|
||
if (sel >= n_args)
|
||
error (_("Invalid probe argument %d -- probe has %u arguments available"),
|
||
sel, n_args);
|
||
|
||
return evaluate_probe_argument (pc_probe.probe, sel, frame);
|
||
}
|
||
|
||
/* This is called to compile one of the $_probe_arg* convenience
|
||
variables into an agent expression. */
|
||
|
||
static void
|
||
compile_probe_arg (struct internalvar *ivar, struct agent_expr *expr,
|
||
struct axs_value *value, void *data)
|
||
{
|
||
CORE_ADDR pc = expr->scope;
|
||
int sel = (int) (uintptr_t) data;
|
||
struct bound_probe pc_probe;
|
||
const struct sym_probe_fns *pc_probe_fns;
|
||
int n_args;
|
||
struct frame_info *frame = get_selected_frame (NULL);
|
||
|
||
/* SEL == -1 means "_probe_argc". */
|
||
gdb_assert (sel >= -1);
|
||
|
||
pc_probe = find_probe_by_pc (pc);
|
||
if (pc_probe.probe == NULL)
|
||
error (_("No SystemTap probe at PC %s"), core_addr_to_string (pc));
|
||
|
||
n_args = get_probe_argument_count (pc_probe.probe, frame);
|
||
|
||
if (sel == -1)
|
||
{
|
||
value->kind = axs_rvalue;
|
||
value->type = builtin_type (expr->gdbarch)->builtin_int;
|
||
ax_const_l (expr, n_args);
|
||
return;
|
||
}
|
||
|
||
gdb_assert (sel >= 0);
|
||
if (sel >= n_args)
|
||
error (_("Invalid probe argument %d -- probe has %d arguments available"),
|
||
sel, n_args);
|
||
|
||
pc_probe.probe->pops->compile_to_ax (pc_probe.probe, expr, value, sel);
|
||
}
|
||
|
||
|
||
|
||
/* Set or clear a SystemTap semaphore. ADDRESS is the semaphore's
|
||
address. SET is zero if the semaphore should be cleared, or one
|
||
if it should be set. This is a helper function for `stap_semaphore_down'
|
||
and `stap_semaphore_up'. */
|
||
|
||
static void
|
||
stap_modify_semaphore (CORE_ADDR address, int set, struct gdbarch *gdbarch)
|
||
{
|
||
gdb_byte bytes[sizeof (LONGEST)];
|
||
/* The ABI specifies "unsigned short". */
|
||
struct type *type = builtin_type (gdbarch)->builtin_unsigned_short;
|
||
ULONGEST value;
|
||
|
||
if (address == 0)
|
||
return;
|
||
|
||
/* Swallow errors. */
|
||
if (target_read_memory (address, bytes, TYPE_LENGTH (type)) != 0)
|
||
{
|
||
warning (_("Could not read the value of a SystemTap semaphore."));
|
||
return;
|
||
}
|
||
|
||
value = extract_unsigned_integer (bytes, TYPE_LENGTH (type),
|
||
gdbarch_byte_order (gdbarch));
|
||
/* Note that we explicitly don't worry about overflow or
|
||
underflow. */
|
||
if (set)
|
||
++value;
|
||
else
|
||
--value;
|
||
|
||
store_unsigned_integer (bytes, TYPE_LENGTH (type),
|
||
gdbarch_byte_order (gdbarch), value);
|
||
|
||
if (target_write_memory (address, bytes, TYPE_LENGTH (type)) != 0)
|
||
warning (_("Could not write the value of a SystemTap semaphore."));
|
||
}
|
||
|
||
/* Set a SystemTap semaphore. SEM is the semaphore's address. Semaphores
|
||
act as reference counters, so calls to this function must be paired with
|
||
calls to `stap_semaphore_down'.
|
||
|
||
This function and `stap_semaphore_down' race with another tool changing
|
||
the probes, but that is too rare to care. */
|
||
|
||
static void
|
||
stap_set_semaphore (struct probe *probe_generic, struct objfile *objfile,
|
||
struct gdbarch *gdbarch)
|
||
{
|
||
struct stap_probe *probe = (struct stap_probe *) probe_generic;
|
||
CORE_ADDR addr;
|
||
|
||
gdb_assert (probe_generic->pops == &stap_probe_ops);
|
||
|
||
addr = (probe->sem_addr
|
||
+ ANOFFSET (objfile->section_offsets, SECT_OFF_DATA (objfile)));
|
||
stap_modify_semaphore (addr, 1, gdbarch);
|
||
}
|
||
|
||
/* Clear a SystemTap semaphore. SEM is the semaphore's address. */
|
||
|
||
static void
|
||
stap_clear_semaphore (struct probe *probe_generic, struct objfile *objfile,
|
||
struct gdbarch *gdbarch)
|
||
{
|
||
struct stap_probe *probe = (struct stap_probe *) probe_generic;
|
||
CORE_ADDR addr;
|
||
|
||
gdb_assert (probe_generic->pops == &stap_probe_ops);
|
||
|
||
addr = (probe->sem_addr
|
||
+ ANOFFSET (objfile->section_offsets, SECT_OFF_DATA (objfile)));
|
||
stap_modify_semaphore (addr, 0, gdbarch);
|
||
}
|
||
|
||
/* Implementation of `$_probe_arg*' set of variables. */
|
||
|
||
static const struct internalvar_funcs probe_funcs =
|
||
{
|
||
compute_probe_arg,
|
||
compile_probe_arg,
|
||
NULL
|
||
};
|
||
|
||
/* Helper function that parses the information contained in a
|
||
SystemTap's probe. Basically, the information consists in:
|
||
|
||
- Probe's PC address;
|
||
- Link-time section address of `.stapsdt.base' section;
|
||
- Link-time address of the semaphore variable, or ZERO if the
|
||
probe doesn't have an associated semaphore;
|
||
- Probe's provider name;
|
||
- Probe's name;
|
||
- Probe's argument format
|
||
|
||
This function returns 1 if the handling was successful, and zero
|
||
otherwise. */
|
||
|
||
static void
|
||
handle_stap_probe (struct objfile *objfile, struct sdt_note *el,
|
||
VEC (probe_p) **probesp, CORE_ADDR base)
|
||
{
|
||
bfd *abfd = objfile->obfd;
|
||
int size = bfd_get_arch_size (abfd) / 8;
|
||
struct gdbarch *gdbarch = get_objfile_arch (objfile);
|
||
struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr;
|
||
CORE_ADDR base_ref;
|
||
const char *probe_args = NULL;
|
||
struct stap_probe *ret;
|
||
|
||
ret = obstack_alloc (&objfile->per_bfd->storage_obstack, sizeof (*ret));
|
||
ret->p.pops = &stap_probe_ops;
|
||
ret->p.arch = gdbarch;
|
||
|
||
/* Provider and the name of the probe. */
|
||
ret->p.provider = (char *) &el->data[3 * size];
|
||
ret->p.name = memchr (ret->p.provider, '\0',
|
||
(char *) el->data + el->size - ret->p.provider);
|
||
/* Making sure there is a name. */
|
||
if (ret->p.name == NULL)
|
||
{
|
||
complaint (&symfile_complaints, _("corrupt probe name when "
|
||
"reading `%s'"),
|
||
objfile_name (objfile));
|
||
|
||
/* There is no way to use a probe without a name or a provider, so
|
||
returning zero here makes sense. */
|
||
return;
|
||
}
|
||
else
|
||
++ret->p.name;
|
||
|
||
/* Retrieving the probe's address. */
|
||
ret->p.address = extract_typed_address (&el->data[0], ptr_type);
|
||
|
||
/* Link-time sh_addr of `.stapsdt.base' section. */
|
||
base_ref = extract_typed_address (&el->data[size], ptr_type);
|
||
|
||
/* Semaphore address. */
|
||
ret->sem_addr = extract_typed_address (&el->data[2 * size], ptr_type);
|
||
|
||
ret->p.address += base - base_ref;
|
||
if (ret->sem_addr != 0)
|
||
ret->sem_addr += base - base_ref;
|
||
|
||
/* Arguments. We can only extract the argument format if there is a valid
|
||
name for this probe. */
|
||
probe_args = memchr (ret->p.name, '\0',
|
||
(char *) el->data + el->size - ret->p.name);
|
||
|
||
if (probe_args != NULL)
|
||
++probe_args;
|
||
|
||
if (probe_args == NULL
|
||
|| (memchr (probe_args, '\0', (char *) el->data + el->size - ret->p.name)
|
||
!= el->data + el->size - 1))
|
||
{
|
||
complaint (&symfile_complaints, _("corrupt probe argument when "
|
||
"reading `%s'"),
|
||
objfile_name (objfile));
|
||
/* If the argument string is NULL, it means some problem happened with
|
||
it. So we return 0. */
|
||
return;
|
||
}
|
||
|
||
ret->args_parsed = 0;
|
||
ret->args_u.text = (void *) probe_args;
|
||
|
||
/* Successfully created probe. */
|
||
VEC_safe_push (probe_p, *probesp, (struct probe *) ret);
|
||
}
|
||
|
||
/* Helper function which tries to find the base address of the SystemTap
|
||
base section named STAP_BASE_SECTION_NAME. */
|
||
|
||
static void
|
||
get_stap_base_address_1 (bfd *abfd, asection *sect, void *obj)
|
||
{
|
||
asection **ret = obj;
|
||
|
||
if ((sect->flags & (SEC_DATA | SEC_ALLOC | SEC_HAS_CONTENTS))
|
||
&& sect->name && !strcmp (sect->name, STAP_BASE_SECTION_NAME))
|
||
*ret = sect;
|
||
}
|
||
|
||
/* Helper function which iterates over every section in the BFD file,
|
||
trying to find the base address of the SystemTap base section.
|
||
Returns 1 if found (setting BASE to the proper value), zero otherwise. */
|
||
|
||
static int
|
||
get_stap_base_address (bfd *obfd, bfd_vma *base)
|
||
{
|
||
asection *ret = NULL;
|
||
|
||
bfd_map_over_sections (obfd, get_stap_base_address_1, (void *) &ret);
|
||
|
||
if (ret == NULL)
|
||
{
|
||
complaint (&symfile_complaints, _("could not obtain base address for "
|
||
"SystemTap section on objfile `%s'."),
|
||
obfd->filename);
|
||
return 0;
|
||
}
|
||
|
||
if (base != NULL)
|
||
*base = ret->vma;
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Helper function for `elf_get_probes', which gathers information about all
|
||
SystemTap probes from OBJFILE. */
|
||
|
||
static void
|
||
stap_get_probes (VEC (probe_p) **probesp, struct objfile *objfile)
|
||
{
|
||
/* If we are here, then this is the first time we are parsing the
|
||
SystemTap probe's information. We basically have to count how many
|
||
probes the objfile has, and then fill in the necessary information
|
||
for each one. */
|
||
bfd *obfd = objfile->obfd;
|
||
bfd_vma base;
|
||
struct sdt_note *iter;
|
||
unsigned save_probesp_len = VEC_length (probe_p, *probesp);
|
||
|
||
if (objfile->separate_debug_objfile_backlink != NULL)
|
||
{
|
||
/* This is a .debug file, not the objfile itself. */
|
||
return;
|
||
}
|
||
|
||
if (elf_tdata (obfd)->sdt_note_head == NULL)
|
||
{
|
||
/* There isn't any probe here. */
|
||
return;
|
||
}
|
||
|
||
if (!get_stap_base_address (obfd, &base))
|
||
{
|
||
/* There was an error finding the base address for the section.
|
||
Just return NULL. */
|
||
return;
|
||
}
|
||
|
||
/* Parsing each probe's information. */
|
||
for (iter = elf_tdata (obfd)->sdt_note_head;
|
||
iter != NULL;
|
||
iter = iter->next)
|
||
{
|
||
/* We first have to handle all the information about the
|
||
probe which is present in the section. */
|
||
handle_stap_probe (objfile, iter, probesp, base);
|
||
}
|
||
|
||
if (save_probesp_len == VEC_length (probe_p, *probesp))
|
||
{
|
||
/* If we are here, it means we have failed to parse every known
|
||
probe. */
|
||
complaint (&symfile_complaints, _("could not parse SystemTap probe(s) "
|
||
"from inferior"));
|
||
return;
|
||
}
|
||
}
|
||
|
||
static int
|
||
stap_probe_is_linespec (const char **linespecp)
|
||
{
|
||
static const char *const keywords[] = { "-pstap", "-probe-stap", NULL };
|
||
|
||
return probe_is_linespec_by_keyword (linespecp, keywords);
|
||
}
|
||
|
||
static void
|
||
stap_gen_info_probes_table_header (VEC (info_probe_column_s) **heads)
|
||
{
|
||
info_probe_column_s stap_probe_column;
|
||
|
||
stap_probe_column.field_name = "semaphore";
|
||
stap_probe_column.print_name = _("Semaphore");
|
||
|
||
VEC_safe_push (info_probe_column_s, *heads, &stap_probe_column);
|
||
}
|
||
|
||
static void
|
||
stap_gen_info_probes_table_values (struct probe *probe_generic,
|
||
VEC (const_char_ptr) **ret)
|
||
{
|
||
struct stap_probe *probe = (struct stap_probe *) probe_generic;
|
||
struct gdbarch *gdbarch;
|
||
const char *val = NULL;
|
||
|
||
gdb_assert (probe_generic->pops == &stap_probe_ops);
|
||
|
||
gdbarch = probe->p.arch;
|
||
|
||
if (probe->sem_addr != 0)
|
||
val = print_core_address (gdbarch, probe->sem_addr);
|
||
|
||
VEC_safe_push (const_char_ptr, *ret, val);
|
||
}
|
||
|
||
/* SystemTap probe_ops. */
|
||
|
||
static const struct probe_ops stap_probe_ops =
|
||
{
|
||
stap_probe_is_linespec,
|
||
stap_get_probes,
|
||
stap_get_probe_address,
|
||
stap_get_probe_argument_count,
|
||
stap_can_evaluate_probe_arguments,
|
||
stap_evaluate_probe_argument,
|
||
stap_compile_to_ax,
|
||
stap_set_semaphore,
|
||
stap_clear_semaphore,
|
||
stap_probe_destroy,
|
||
stap_gen_info_probes_table_header,
|
||
stap_gen_info_probes_table_values,
|
||
};
|
||
|
||
/* Implementation of the `info probes stap' command. */
|
||
|
||
static void
|
||
info_probes_stap_command (char *arg, int from_tty)
|
||
{
|
||
info_probes_for_ops (arg, from_tty, &stap_probe_ops);
|
||
}
|
||
|
||
void _initialize_stap_probe (void);
|
||
|
||
void
|
||
_initialize_stap_probe (void)
|
||
{
|
||
VEC_safe_push (probe_ops_cp, all_probe_ops, &stap_probe_ops);
|
||
|
||
add_setshow_zuinteger_cmd ("stap-expression", class_maintenance,
|
||
&stap_expression_debug,
|
||
_("Set SystemTap expression debugging."),
|
||
_("Show SystemTap expression debugging."),
|
||
_("When non-zero, the internal representation "
|
||
"of SystemTap expressions will be printed."),
|
||
NULL,
|
||
show_stapexpressiondebug,
|
||
&setdebuglist, &showdebuglist);
|
||
|
||
create_internalvar_type_lazy ("_probe_argc", &probe_funcs,
|
||
(void *) (uintptr_t) -1);
|
||
create_internalvar_type_lazy ("_probe_arg0", &probe_funcs,
|
||
(void *) (uintptr_t) 0);
|
||
create_internalvar_type_lazy ("_probe_arg1", &probe_funcs,
|
||
(void *) (uintptr_t) 1);
|
||
create_internalvar_type_lazy ("_probe_arg2", &probe_funcs,
|
||
(void *) (uintptr_t) 2);
|
||
create_internalvar_type_lazy ("_probe_arg3", &probe_funcs,
|
||
(void *) (uintptr_t) 3);
|
||
create_internalvar_type_lazy ("_probe_arg4", &probe_funcs,
|
||
(void *) (uintptr_t) 4);
|
||
create_internalvar_type_lazy ("_probe_arg5", &probe_funcs,
|
||
(void *) (uintptr_t) 5);
|
||
create_internalvar_type_lazy ("_probe_arg6", &probe_funcs,
|
||
(void *) (uintptr_t) 6);
|
||
create_internalvar_type_lazy ("_probe_arg7", &probe_funcs,
|
||
(void *) (uintptr_t) 7);
|
||
create_internalvar_type_lazy ("_probe_arg8", &probe_funcs,
|
||
(void *) (uintptr_t) 8);
|
||
create_internalvar_type_lazy ("_probe_arg9", &probe_funcs,
|
||
(void *) (uintptr_t) 9);
|
||
create_internalvar_type_lazy ("_probe_arg10", &probe_funcs,
|
||
(void *) (uintptr_t) 10);
|
||
create_internalvar_type_lazy ("_probe_arg11", &probe_funcs,
|
||
(void *) (uintptr_t) 11);
|
||
|
||
add_cmd ("stap", class_info, info_probes_stap_command,
|
||
_("\
|
||
Show information about SystemTap static probes.\n\
|
||
Usage: info probes stap [PROVIDER [NAME [OBJECT]]]\n\
|
||
Each argument is a regular expression, used to select probes.\n\
|
||
PROVIDER matches probe provider names.\n\
|
||
NAME matches the probe names.\n\
|
||
OBJECT matches the executable or shared library name."),
|
||
info_probes_cmdlist_get ());
|
||
|
||
}
|