| /* SystemTap probe support for GDB. |
| |
| Copyright (C) 2012-2021 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| 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 3 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, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "stap-probe.h" |
| #include "probe.h" |
| #include "ui-out.h" |
| #include "objfiles.h" |
| #include "arch-utils.h" |
| #include "command.h" |
| #include "gdbcmd.h" |
| #include "filenames.h" |
| #include "value.h" |
| #include "ax.h" |
| #include "ax-gdb.h" |
| #include "complaints.h" |
| #include "cli/cli-utils.h" |
| #include "linespec.h" |
| #include "user-regs.h" |
| #include "parser-defs.h" |
| #include "language.h" |
| #include "elf-bfd.h" |
| #include "expop.h" |
| #include <unordered_map> |
| #include "gdbsupport/hash_enum.h" |
| |
| #include <ctype.h> |
| |
| /* The name of the SystemTap section where we will find information about |
| the probes. */ |
| |
| #define STAP_BASE_SECTION_NAME ".stapsdt.base" |
| |
| /* Should we display debug information for the probe's argument expression |
| parsing? */ |
| |
| static unsigned int stap_expression_debug = 0; |
| |
| /* The various possibilities of bitness defined for a probe's argument. |
| |
| The relationship is: |
| |
| - STAP_ARG_BITNESS_UNDEFINED: The user hasn't specified the bitness. |
| - STAP_ARG_BITNESS_8BIT_UNSIGNED: argument string starts with `1@'. |
| - STAP_ARG_BITNESS_8BIT_SIGNED: argument string starts with `-1@'. |
| - STAP_ARG_BITNESS_16BIT_UNSIGNED: argument string starts with `2@'. |
| - STAP_ARG_BITNESS_16BIT_SIGNED: argument string starts with `-2@'. |
| - STAP_ARG_BITNESS_32BIT_UNSIGNED: argument string starts with `4@'. |
| - STAP_ARG_BITNESS_32BIT_SIGNED: argument string starts with `-4@'. |
| - STAP_ARG_BITNESS_64BIT_UNSIGNED: argument string starts with `8@'. |
| - STAP_ARG_BITNESS_64BIT_SIGNED: argument string starts with `-8@'. */ |
| |
| enum stap_arg_bitness |
| { |
| STAP_ARG_BITNESS_UNDEFINED, |
| STAP_ARG_BITNESS_8BIT_UNSIGNED, |
| STAP_ARG_BITNESS_8BIT_SIGNED, |
| STAP_ARG_BITNESS_16BIT_UNSIGNED, |
| STAP_ARG_BITNESS_16BIT_SIGNED, |
| STAP_ARG_BITNESS_32BIT_UNSIGNED, |
| STAP_ARG_BITNESS_32BIT_SIGNED, |
| STAP_ARG_BITNESS_64BIT_UNSIGNED, |
| STAP_ARG_BITNESS_64BIT_SIGNED, |
| }; |
| |
| /* The following structure represents a single argument for the probe. */ |
| |
| struct stap_probe_arg |
| { |
| /* Constructor for stap_probe_arg. */ |
| stap_probe_arg (enum stap_arg_bitness bitness_, struct type *atype_, |
| expression_up &&aexpr_) |
| : bitness (bitness_), atype (atype_), aexpr (std::move (aexpr_)) |
| {} |
| |
| /* The bitness of this argument. */ |
| enum stap_arg_bitness bitness; |
| |
| /* The corresponding `struct type *' to the bitness. */ |
| struct type *atype; |
| |
| /* The argument converted to an internal GDB expression. */ |
| expression_up aexpr; |
| }; |
| |
| /* Class that implements the static probe methods for "stap" probes. */ |
| |
| class stap_static_probe_ops : public static_probe_ops |
| { |
| public: |
| /* We need a user-provided constructor to placate some compilers. |
| See PR build/24937. */ |
| stap_static_probe_ops () |
| { |
| } |
| |
| /* See probe.h. */ |
| bool is_linespec (const char **linespecp) const override; |
| |
| /* See probe.h. */ |
| void get_probes (std::vector<std::unique_ptr<probe>> *probesp, |
| struct objfile *objfile) const override; |
| |
| /* See probe.h. */ |
| const char *type_name () const override; |
| |
| /* See probe.h. */ |
| std::vector<struct info_probe_column> gen_info_probes_table_header |
| () const override; |
| }; |
| |
| /* SystemTap static_probe_ops. */ |
| |
| const stap_static_probe_ops stap_static_probe_ops {}; |
| |
| class stap_probe : public probe |
| { |
| public: |
| /* Constructor for stap_probe. */ |
| stap_probe (std::string &&name_, std::string &&provider_, CORE_ADDR address_, |
| struct gdbarch *arch_, CORE_ADDR sem_addr, const char *args_text) |
| : probe (std::move (name_), std::move (provider_), address_, arch_), |
| m_sem_addr (sem_addr), |
| m_have_parsed_args (false), m_unparsed_args_text (args_text) |
| {} |
| |
| /* See probe.h. */ |
| CORE_ADDR get_relocated_address (struct objfile *objfile) override; |
| |
| /* See probe.h. */ |
| unsigned get_argument_count (struct gdbarch *gdbarch) override; |
| |
| /* See probe.h. */ |
| bool can_evaluate_arguments () const override; |
| |
| /* See probe.h. */ |
| struct value *evaluate_argument (unsigned n, |
| struct frame_info *frame) override; |
| |
| /* See probe.h. */ |
| void compile_to_ax (struct agent_expr *aexpr, |
| struct axs_value *axs_value, |
| unsigned n) override; |
| |
| /* See probe.h. */ |
| void set_semaphore (struct objfile *objfile, |
| struct gdbarch *gdbarch) override; |
| |
| /* See probe.h. */ |
| void clear_semaphore (struct objfile *objfile, |
| struct gdbarch *gdbarch) override; |
| |
| /* See probe.h. */ |
| const static_probe_ops *get_static_ops () const override; |
| |
| /* See probe.h. */ |
| std::vector<const char *> gen_info_probes_table_values () const override; |
| |
| /* Return argument N of probe. |
| |
| If the probe's arguments have not been parsed yet, parse them. If |
| there are no arguments, throw an exception (error). Otherwise, |
| return the requested argument. */ |
| struct stap_probe_arg *get_arg_by_number (unsigned n, |
| struct gdbarch *gdbarch) |
| { |
| if (!m_have_parsed_args) |
| this->parse_arguments (gdbarch); |
| |
| gdb_assert (m_have_parsed_args); |
| if (m_parsed_args.empty ()) |
| internal_error (__FILE__, __LINE__, |
| _("Probe '%s' apparently does not have arguments, but \n" |
| "GDB is requesting its argument number %u anyway. " |
| "This should not happen. Please report this bug."), |
| this->get_name ().c_str (), n); |
| |
| if (n > m_parsed_args.size ()) |
| internal_error (__FILE__, __LINE__, |
| _("Probe '%s' has %d arguments, but GDB is requesting\n" |
| "argument %u. This should not happen. Please\n" |
| "report this bug."), |
| this->get_name ().c_str (), |
| (int) m_parsed_args.size (), n); |
| |
| return &m_parsed_args[n]; |
| } |
| |
| /* Function which parses an argument string from the 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. */ |
| void parse_arguments (struct gdbarch *gdbarch); |
| |
| private: |
| /* If the probe has a semaphore associated, then this is the value of |
| it, relative to SECT_OFF_DATA. */ |
| CORE_ADDR m_sem_addr; |
| |
| /* True if the arguments have been parsed. */ |
| bool m_have_parsed_args; |
| |
| /* The text version of the probe's arguments, unparsed. */ |
| const char *m_unparsed_args_text; |
| |
| /* Information about each argument. This is an array of `stap_probe_arg', |
| with each entry representing one argument. This is only valid if |
| M_ARGS_PARSED is true. */ |
| std::vector<struct stap_probe_arg> m_parsed_args; |
| }; |
| |
| /* When parsing the arguments, we have to establish different precedences |
| for the various kinds of asm operators. This enumeration represents those |
| precedences. |
| |
| This logic behind this is available at |
| <http://sourceware.org/binutils/docs/as/Infix-Ops.html#Infix-Ops>, or using |
| the command "info '(as)Infix Ops'". */ |
| |
| enum stap_operand_prec |
| { |
| /* Lowest precedence, used for non-recognized operands or for the beginning |
| of the parsing process. */ |
| STAP_OPERAND_PREC_NONE = 0, |
| |
| /* Precedence of logical OR. */ |
| STAP_OPERAND_PREC_LOGICAL_OR, |
| |
| /* Precedence of logical AND. */ |
| STAP_OPERAND_PREC_LOGICAL_AND, |
| |
| /* Precedence of additive (plus, minus) and comparative (equal, less, |
| greater-than, etc) operands. */ |
| STAP_OPERAND_PREC_ADD_CMP, |
| |
| /* Precedence of bitwise operands (bitwise OR, XOR, bitwise AND, |
| logical NOT). */ |
| STAP_OPERAND_PREC_BITWISE, |
| |
| /* Precedence of multiplicative operands (multiplication, division, |
| remainder, left shift and right shift). */ |
| STAP_OPERAND_PREC_MUL |
| }; |
| |
| static expr::operation_up stap_parse_argument_1 (struct stap_parse_info *p, |
| expr::operation_up &&lhs, |
| enum stap_operand_prec prec) |
| ATTRIBUTE_UNUSED_RESULT; |
| |
| static expr::operation_up stap_parse_argument_conditionally |
| (struct stap_parse_info *p) ATTRIBUTE_UNUSED_RESULT; |
| |
| /* Returns true if *S is an operator, false otherwise. */ |
| |
| static bool stap_is_operator (const char *op); |
| |
| static void |
| show_stapexpressiondebug (struct ui_file *file, int from_tty, |
| struct cmd_list_element *c, const char *value) |
| { |
| fprintf_filtered (file, _("SystemTap Probe expression debugging is %s.\n"), |
| value); |
| } |
| |
| /* Returns the operator precedence level of OP, or STAP_OPERAND_PREC_NONE |
| if the operator code was not recognized. */ |
| |
| static enum stap_operand_prec |
| stap_get_operator_prec (enum exp_opcode op) |
| { |
| switch (op) |
| { |
| case BINOP_LOGICAL_OR: |
| return STAP_OPERAND_PREC_LOGICAL_OR; |
| |
| case BINOP_LOGICAL_AND: |
| return STAP_OPERAND_PREC_LOGICAL_AND; |
| |
| case BINOP_ADD: |
| case BINOP_SUB: |
| case BINOP_EQUAL: |
| case BINOP_NOTEQUAL: |
| case BINOP_LESS: |
| case BINOP_LEQ: |
| case BINOP_GTR: |
| case BINOP_GEQ: |
| return STAP_OPERAND_PREC_ADD_CMP; |
| |
| case BINOP_BITWISE_IOR: |
| case BINOP_BITWISE_AND: |
| case BINOP_BITWISE_XOR: |
| case UNOP_LOGICAL_NOT: |
| return STAP_OPERAND_PREC_BITWISE; |
| |
| case BINOP_MUL: |
| case BINOP_DIV: |
| case BINOP_REM: |
| case BINOP_LSH: |
| case BINOP_RSH: |
| return STAP_OPERAND_PREC_MUL; |
| |
| default: |
| return STAP_OPERAND_PREC_NONE; |
| } |
| } |
| |
| /* Given S, read the operator in it. Return the EXP_OPCODE which |
| represents the operator detected, or throw an error if no operator |
| was found. */ |
| |
| static enum exp_opcode |
| stap_get_opcode (const char **s) |
| { |
| const char c = **s; |
| enum exp_opcode op; |
| |
| *s += 1; |
| |
| switch (c) |
| { |
| case '*': |
| op = BINOP_MUL; |
| break; |
| |
| case '/': |
| op = BINOP_DIV; |
| break; |
| |
| case '%': |
| op = BINOP_REM; |
| break; |
| |
| case '<': |
| op = BINOP_LESS; |
| if (**s == '<') |
| { |
| *s += 1; |
| op = BINOP_LSH; |
| } |
| else if (**s == '=') |
| { |
| *s += 1; |
| op = BINOP_LEQ; |
| } |
| else if (**s == '>') |
| { |
| *s += 1; |
| op = BINOP_NOTEQUAL; |
| } |
| break; |
| |
| case '>': |
| op = BINOP_GTR; |
| if (**s == '>') |
| { |
| *s += 1; |
| op = BINOP_RSH; |
| } |
| else if (**s == '=') |
| { |
| *s += 1; |
| op = BINOP_GEQ; |
| } |
| break; |
| |
| case '|': |
| op = BINOP_BITWISE_IOR; |
| if (**s == '|') |
| { |
| *s += 1; |
| op = BINOP_LOGICAL_OR; |
| } |
| break; |
| |
| case '&': |
| op = BINOP_BITWISE_AND; |
| if (**s == '&') |
| { |
| *s += 1; |
| op = BINOP_LOGICAL_AND; |
| } |
| break; |
| |
| case '^': |
| op = BINOP_BITWISE_XOR; |
| break; |
| |
| case '!': |
| op = UNOP_LOGICAL_NOT; |
| break; |
| |
| case '+': |
| op = BINOP_ADD; |
| break; |
| |
| case '-': |
| op = BINOP_SUB; |
| break; |
| |
| case '=': |
| gdb_assert (**s == '='); |
| op = BINOP_EQUAL; |
| break; |
| |
| default: |
| error (_("Invalid opcode in expression `%s' for SystemTap" |
| "probe"), *s); |
| } |
| |
| return op; |
| } |
| |
| typedef expr::operation_up binop_maker_ftype (expr::operation_up &&, |
| expr::operation_up &&); |
| /* Map from an expression opcode to a function that can create a |
| binary operation of that type. */ |
| static std::unordered_map<exp_opcode, binop_maker_ftype *, |
| gdb::hash_enum<exp_opcode>> stap_maker_map; |
| |
| /* Helper function to create a binary operation. */ |
| static expr::operation_up |
| stap_make_binop (enum exp_opcode opcode, expr::operation_up &&lhs, |
| expr::operation_up &&rhs) |
| { |
| auto iter = stap_maker_map.find (opcode); |
| gdb_assert (iter != stap_maker_map.end ()); |
| return iter->second (std::move (lhs), std::move (rhs)); |
| } |
| |
| /* Given the bitness of the argument, represented by B, return the |
| corresponding `struct type *', or throw an error if B is |
| unknown. */ |
| |
| static struct type * |
| stap_get_expected_argument_type (struct gdbarch *gdbarch, |
| enum stap_arg_bitness b, |
| const char *probe_name) |
| { |
| switch (b) |
| { |
| case STAP_ARG_BITNESS_UNDEFINED: |
| if (gdbarch_addr_bit (gdbarch) == 32) |
| return builtin_type (gdbarch)->builtin_uint32; |
| else |
| return builtin_type (gdbarch)->builtin_uint64; |
| |
| case STAP_ARG_BITNESS_8BIT_UNSIGNED: |
| return builtin_type (gdbarch)->builtin_uint8; |
| |
| case STAP_ARG_BITNESS_8BIT_SIGNED: |
| return builtin_type (gdbarch)->builtin_int8; |
| |
| case STAP_ARG_BITNESS_16BIT_UNSIGNED: |
| return builtin_type (gdbarch)->builtin_uint16; |
| |
| case STAP_ARG_BITNESS_16BIT_SIGNED: |
| return builtin_type (gdbarch)->builtin_int16; |
| |
| case STAP_ARG_BITNESS_32BIT_SIGNED: |
| return builtin_type (gdbarch)->builtin_int32; |
| |
| case STAP_ARG_BITNESS_32BIT_UNSIGNED: |
| return builtin_type (gdbarch)->builtin_uint32; |
| |
| case STAP_ARG_BITNESS_64BIT_SIGNED: |
| return builtin_type (gdbarch)->builtin_int64; |
| |
| case STAP_ARG_BITNESS_64BIT_UNSIGNED: |
| return builtin_type (gdbarch)->builtin_uint64; |
| |
| default: |
| error (_("Undefined bitness for probe '%s'."), probe_name); |
| break; |
| } |
| } |
| |
| /* Helper function to check for a generic list of prefixes. 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 |
| prefix. PREFIXES is the list of expected prefixes. |
| |
| This function does a case-insensitive match. |
| |
| Return true if any prefix has been found, false otherwise. */ |
| |
| static bool |
| stap_is_generic_prefix (struct gdbarch *gdbarch, const char *s, |
| const char **r, const char *const *prefixes) |
| { |
| const char *const *p; |
| |
| if (prefixes == NULL) |
| { |
| if (r != NULL) |
| *r = ""; |
| |
| return true; |
| } |
| |
| for (p = prefixes; *p != NULL; ++p) |
| if (strncasecmp (s, *p, strlen (*p)) == 0) |
| { |
| if (r != NULL) |
| *r = *p; |
| |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Return true if S points to a register prefix, false otherwise. For |
| a description of the arguments, look at stap_is_generic_prefix. */ |
| |
| static bool |
| stap_is_register_prefix (struct gdbarch *gdbarch, const char *s, |
| const char **r) |
| { |
| const char *const *t = gdbarch_stap_register_prefixes (gdbarch); |
| |
| return stap_is_generic_prefix (gdbarch, s, r, t); |
| } |
| |
| /* Return true if S points to a register indirection prefix, false |
| otherwise. For a description of the arguments, look at |
| stap_is_generic_prefix. */ |
| |
| static bool |
| stap_is_register_indirection_prefix (struct gdbarch *gdbarch, const char *s, |
| const char **r) |
| { |
| const char *const *t = gdbarch_stap_register_indirection_prefixes (gdbarch); |
| |
| return stap_is_generic_prefix (gdbarch, s, r, t); |
| } |
| |
| /* Return true if S points to an integer prefix, false otherwise. For |
| a description of the arguments, look at stap_is_generic_prefix. |
| |
| This function takes care of analyzing whether we are dealing with |
| an expected integer prefix, or, if there is no integer prefix to be |
| expected, whether we are dealing with a digit. It does a |
| case-insensitive match. */ |
| |
| static bool |
| stap_is_integer_prefix (struct gdbarch *gdbarch, const char *s, |
| const char **r) |
| { |
| const char *const *t = gdbarch_stap_integer_prefixes (gdbarch); |
| const char *const *p; |
| |
| if (t == NULL) |
| { |
| /* A NULL value here means that integers do not have a prefix. |
| We just check for a digit then. */ |
| if (r != NULL) |
| *r = ""; |
| |
| return isdigit (*s) > 0; |
| } |
| |
| 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 true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /* 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 true if a suffix has |
| been found, false 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 bool |
| stap_generic_check_suffix (struct gdbarch *gdbarch, const char *s, |
| const char **r, const char *const *suffixes) |
| { |
| const char *const *p; |
| bool found = false; |
| |
| if (suffixes == NULL) |
| { |
| if (r != NULL) |
| *r = ""; |
| |
| return true; |
| } |
| |
| for (p = suffixes; *p != NULL; ++p) |
| if (strncasecmp (s, *p, strlen (*p)) == 0) |
| { |
| if (r != NULL) |
| *r = *p; |
| |
| found = true; |
| break; |
| } |
| |
| return found; |
| } |
| |
| /* Return true if S points to an integer suffix, false otherwise. For |
| a description of the arguments, look at |
| stap_generic_check_suffix. */ |
| |
| static bool |
| 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 true if S points to a register suffix, false otherwise. For |
| a description of the arguments, look at |
| stap_generic_check_suffix. */ |
| |
| static bool |
| 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 true if S points to a register indirection suffix, false |
| otherwise. For a description of the arguments, look at |
| stap_generic_check_suffix. */ |
| |
| static bool |
| 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 expr::operation_up |
| stap_parse_register_operand (struct stap_parse_info *p) |
| { |
| /* Simple flag to indicate whether we have seen a minus signal before |
| certain number. */ |
| bool got_minus = false; |
| /* Flag to indicate whether this register access is being |
| indirected. */ |
| bool indirect_p = false; |
| struct gdbarch *gdbarch = p->gdbarch; |
| /* Variables used to extract the register name from the probe's |
| argument. */ |
| const char *start; |
| const char *gdb_reg_prefix = gdbarch_stap_gdb_register_prefix (gdbarch); |
| const char *gdb_reg_suffix = gdbarch_stap_gdb_register_suffix (gdbarch); |
| const char *reg_prefix; |
| const char *reg_ind_prefix; |
| const char *reg_suffix; |
| const char *reg_ind_suffix; |
| |
| using namespace expr; |
| |
| /* 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; |
| } |
| else if (*p->arg == '-') |
| { |
| got_minus = true; |
| ++p->arg; |
| } |
| |
| struct type *long_type = builtin_type (gdbarch)->builtin_long; |
| operation_up disp_op; |
| if (isdigit (*p->arg)) |
| { |
| /* The value of the displacement. */ |
| long displacement; |
| char *endp; |
| |
| displacement = strtol (p->arg, &endp, 10); |
| p->arg = endp; |
| |
| /* Generating the expression for the displacement. */ |
| if (got_minus) |
| displacement = -displacement; |
| disp_op = make_operation<long_const_operation> (long_type, displacement); |
| } |
| |
| /* Getting rid of register indirection prefix. */ |
| if (stap_is_register_indirection_prefix (gdbarch, p->arg, ®_ind_prefix)) |
| { |
| indirect_p = true; |
| p->arg += strlen (reg_ind_prefix); |
| } |
| |
| if (disp_op != nullptr && !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; |
| |
| std::string regname (start, p->arg - start); |
| |
| /* We only add the GDB's register prefix/suffix if we are dealing with |
| a numeric register. */ |
| if (isdigit (*start)) |
| { |
| if (gdb_reg_prefix != NULL) |
| regname = gdb_reg_prefix + regname; |
| |
| if (gdb_reg_suffix != NULL) |
| regname += gdb_reg_suffix; |
| } |
| |
| int regnum = user_reg_map_name_to_regnum (gdbarch, regname.c_str (), |
| regname.size ()); |
| |
| /* Is this a valid register name? */ |
| if (regnum == -1) |
| error (_("Invalid register name `%s' on expression `%s'."), |
| regname.c_str (), p->saved_arg); |
| |
| /* Check if there's any special treatment that the arch-specific |
| code would like to perform on the register name. */ |
| if (gdbarch_stap_adjust_register_p (gdbarch)) |
| { |
| std::string newregname |
| = gdbarch_stap_adjust_register (gdbarch, p, regname, regnum); |
| |
| if (regname != newregname) |
| { |
| /* This is just a check we perform to make sure that the |
| arch-dependent code has provided us with a valid |
| register name. */ |
| regnum = user_reg_map_name_to_regnum (gdbarch, newregname.c_str (), |
| newregname.size ()); |
| |
| if (regnum == -1) |
| internal_error (__FILE__, __LINE__, |
| _("Invalid register name '%s' after replacing it" |
| " (previous name was '%s')"), |
| newregname.c_str (), regname.c_str ()); |
| |
| regname = std::move (newregname); |
| } |
| } |
| |
| operation_up reg = make_operation<register_operation> (std::move (regname)); |
| |
| if (indirect_p) |
| { |
| if (disp_op != nullptr) |
| reg = make_operation<add_operation> (std::move (disp_op), |
| std::move (reg)); |
| |
| /* Casting to the expected type. */ |
| struct type *arg_ptr_type = lookup_pointer_type (p->arg_type); |
| reg = make_operation<unop_cast_operation> (std::move (reg), |
| arg_ptr_type); |
| reg = make_operation<unop_ind_operation> (std::move (reg)); |
| } |
| |
| /* 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); |
| } |
| |
| return reg; |
| } |
| |
| /* 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 expr::operation_up |
| stap_parse_single_operand (struct stap_parse_info *p) |
| { |
| struct gdbarch *gdbarch = p->gdbarch; |
| const char *int_prefix = NULL; |
| |
| using namespace expr; |
| |
| /* We first try to parse this token as a "special token". */ |
| if (gdbarch_stap_parse_special_token_p (gdbarch)) |
| { |
| operation_up token = gdbarch_stap_parse_special_token (gdbarch, p); |
| if (token != nullptr) |
| return token; |
| } |
| |
| struct type *long_type = builtin_type (gdbarch)->builtin_long; |
| operation_up result; |
| if (*p->arg == '-' || *p->arg == '~' || *p->arg == '+' || *p->arg == '!') |
| { |
| char c = *p->arg; |
| /* We use this variable to do a lookahead. */ |
| const char *tmp = p->arg; |
| bool has_digit = false; |
| |
| /* 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 (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 = true; |
| } |
| |
| 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 != '-' && c != '+') |
| error (_("Invalid operator `%c' for register displacement " |
| "on expression `%s'."), c, p->saved_arg); |
| |
| result = 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; |
| result = stap_parse_argument_conditionally (p); |
| if (c == '-') |
| result = make_operation<unary_neg_operation> (std::move (result)); |
| else if (c == '~') |
| result = (make_operation<unary_complement_operation> |
| (std::move (result))); |
| else if (c == '!') |
| result = (make_operation<unary_logical_not_operation> |
| (std::move (result))); |
| } |
| } |
| 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 (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. */ |
| result = make_operation<long_const_operation> (long_type, number); |
| |
| 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)) |
| result = 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; |
| |
| result = make_operation<long_const_operation> (long_type, number); |
| |
| 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)) |
| result = stap_parse_register_operand (p); |
| else |
| error (_("Operator `%c' not recognized on expression `%s'."), |
| *p->arg, p->saved_arg); |
| |
| return result; |
| } |
| |
| /* 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 expr::operation_up |
| stap_parse_argument_conditionally (struct stap_parse_info *p) |
| { |
| gdb_assert (gdbarch_stap_is_single_operand_p (p->gdbarch)); |
| |
| expr::operation_up result; |
| if (*p->arg == '-' || *p->arg == '~' || *p->arg == '+' || *p->arg == '!' |
| || isdigit (*p->arg) |
| || gdbarch_stap_is_single_operand (p->gdbarch, p->arg)) |
| result = 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 (p->arg); |
| ++p->inside_paren_p; |
| |
| result = stap_parse_argument_1 (p, {}, STAP_OPERAND_PREC_NONE); |
| |
| p->arg = skip_spaces (p->arg); |
| if (*p->arg != ')') |
| error (_("Missing close-parenthesis on expression `%s'."), |
| p->saved_arg); |
| |
| --p->inside_paren_p; |
| ++p->arg; |
| if (p->inside_paren_p) |
| p->arg = skip_spaces (p->arg); |
| } |
| else |
| error (_("Cannot parse expression `%s'."), p->saved_arg); |
| |
| return result; |
| } |
| |
| /* Helper function for `stap_parse_argument'. Please, see its comments to |
| better understand what this function does. */ |
| |
| static expr::operation_up ATTRIBUTE_UNUSED_RESULT |
| stap_parse_argument_1 (struct stap_parse_info *p, |
| expr::operation_up &&lhs_in, |
| 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 (p->arg); |
| |
| using namespace expr; |
| operation_up lhs = std::move (lhs_in); |
| if (lhs == nullptr) |
| { |
| /* 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. */ |
| lhs = stap_parse_argument_conditionally (p); |
| } |
| |
| if (p->inside_paren_p) |
| p->arg = skip_spaces (p->arg); |
| |
| /* 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 (p->arg); |
| |
| /* Parse the right-side of the expression. |
| |
| We save whether the right-side is a parenthesized |
| subexpression because, if it is, we will have to finish |
| processing this part of the expression before continuing. */ |
| bool paren_subexp = *p->arg == '('; |
| |
| operation_up rhs = stap_parse_argument_conditionally (p); |
| if (p->inside_paren_p) |
| p->arg = skip_spaces (p->arg); |
| if (paren_subexp) |
| { |
| lhs = stap_make_binop (opcode, std::move (lhs), std::move (rhs)); |
| continue; |
| } |
| |
| /* 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, using the current |
| right-hand-side as the left-hand-side of the new |
| subexpression. */ |
| rhs = stap_parse_argument_1 (p, std::move (rhs), lookahead_prec); |
| if (p->inside_paren_p) |
| p->arg = skip_spaces (p->arg); |
| } |
| |
| lhs = stap_make_binop (opcode, std::move (lhs), std::move (rhs)); |
| } |
| |
| return lhs; |
| } |
| |
| /* 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 the expression_up generated from |
| parsing the argument. */ |
| |
| static expression_up |
| stap_parse_argument (const char **arg, struct type *atype, |
| struct gdbarch *gdbarch) |
| { |
| /* 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. */ |
| struct stap_parse_info p (*arg, atype, language_def (language_c), |
| gdbarch); |
| |
| using namespace expr; |
| operation_up result = stap_parse_argument_1 (&p, {}, STAP_OPERAND_PREC_NONE); |
| |
| gdb_assert (p.inside_paren_p == 0); |
| |
| /* Casting the final expression to the appropriate type. */ |
| result = make_operation<unop_cast_operation> (std::move (result), atype); |
| p.pstate.set_operation (std::move (result)); |
| |
| p.arg = skip_spaces (p.arg); |
| *arg = p.arg; |
| |
| return p.pstate.release (); |
| } |
| |
| /* Implementation of 'parse_arguments' method. */ |
| |
| void |
| stap_probe::parse_arguments (struct gdbarch *gdbarch) |
| { |
| const char *cur; |
| |
| gdb_assert (!m_have_parsed_args); |
| cur = m_unparsed_args_text; |
| m_have_parsed_args = true; |
| |
| if (cur == NULL || *cur == '\0' || *cur == ':') |
| return; |
| |
| while (*cur != '\0') |
| { |
| enum stap_arg_bitness bitness; |
| bool got_minus = false; |
| |
| /* 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 = true; |
| } |
| |
| /* Defining the bitness. */ |
| switch (*cur) |
| { |
| case '1': |
| bitness = (got_minus ? STAP_ARG_BITNESS_8BIT_SIGNED |
| : STAP_ARG_BITNESS_8BIT_UNSIGNED); |
| break; |
| |
| case '2': |
| bitness = (got_minus ? STAP_ARG_BITNESS_16BIT_SIGNED |
| : STAP_ARG_BITNESS_16BIT_UNSIGNED); |
| break; |
| |
| case '4': |
| bitness = (got_minus ? STAP_ARG_BITNESS_32BIT_SIGNED |
| : STAP_ARG_BITNESS_32BIT_UNSIGNED); |
| break; |
| |
| case '8': |
| bitness = (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, |
| this->get_name ().c_str ()); |
| return; |
| } |
| } |
| /* Discard the number and the `@' sign. */ |
| cur += 2; |
| } |
| else |
| bitness = STAP_ARG_BITNESS_UNDEFINED; |
| |
| struct type *atype |
| = stap_get_expected_argument_type (gdbarch, bitness, |
| this->get_name ().c_str ()); |
| |
| expression_up expr = stap_parse_argument (&cur, atype, gdbarch); |
| |
| if (stap_expression_debug) |
| dump_prefix_expression (expr.get (), gdb_stdlog); |
| |
| m_parsed_args.emplace_back (bitness, atype, std::move (expr)); |
| |
| /* Start it over again. */ |
| cur = skip_spaces (cur); |
| } |
| } |
| |
| /* Helper function to relocate an address. */ |
| |
| static CORE_ADDR |
| relocate_address (CORE_ADDR address, struct objfile *objfile) |
| { |
| return address + objfile->data_section_offset (); |
| } |
| |
| /* Implementation of the get_relocated_address method. */ |
| |
| CORE_ADDR |
| stap_probe::get_relocated_address (struct objfile *objfile) |
| { |
| return relocate_address (this->get_address (), objfile); |
| } |
| |
| /* Given PROBE, returns the number of arguments present in that probe's |
| argument string. */ |
| |
| unsigned |
| stap_probe::get_argument_count (struct gdbarch *gdbarch) |
| { |
| if (!m_have_parsed_args) |
| { |
| if (this->can_evaluate_arguments ()) |
| this->parse_arguments (gdbarch); |
| else |
| { |
| static bool have_warned_stap_incomplete = false; |
| |
| 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 = true; |
| } |
| |
| /* Marking the arguments as "already parsed". */ |
| m_have_parsed_args = true; |
| } |
| } |
| |
| gdb_assert (m_have_parsed_args); |
| return m_parsed_args.size (); |
| } |
| |
| /* Return true if OP is a valid operator inside a probe argument, or |
| false otherwise. */ |
| |
| static bool |
| stap_is_operator (const char *op) |
| { |
| bool ret = true; |
| |
| switch (*op) |
| { |
| case '*': |
| case '/': |
| case '%': |
| case '^': |
| case '!': |
| case '+': |
| case '-': |
| case '<': |
| case '>': |
| case '|': |
| case '&': |
| break; |
| |
| case '=': |
| if (op[1] != '=') |
| ret = false; |
| break; |
| |
| default: |
| /* We didn't find any operator. */ |
| ret = false; |
| } |
| |
| return ret; |
| } |
| |
| /* Implement the `can_evaluate_arguments' method. */ |
| |
| bool |
| stap_probe::can_evaluate_arguments () const |
| { |
| struct gdbarch *gdbarch = this->get_gdbarch (); |
| |
| /* 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. */ |
| |
| struct value * |
| stap_probe::evaluate_argument (unsigned n, struct frame_info *frame) |
| { |
| struct stap_probe_arg *arg; |
| struct gdbarch *gdbarch = get_frame_arch (frame); |
| |
| arg = this->get_arg_by_number (n, gdbarch); |
| return evaluate_expression (arg->aexpr.get (), arg->atype); |
| } |
| |
| /* Compile the probe's argument N (indexed from 0) to agent expression. |
| Assertion is thrown if N does not exist. */ |
| |
| void |
| stap_probe::compile_to_ax (struct agent_expr *expr, struct axs_value *value, |
| unsigned n) |
| { |
| struct stap_probe_arg *arg; |
| |
| arg = this->get_arg_by_number (n, expr->gdbarch); |
| |
| arg->aexpr->op->generate_ax (arg->aexpr.get (), expr, value); |
| |
| require_rvalue (expr, value); |
| value->type = arg->atype; |
| } |
| |
| |
| /* 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_probe::set_semaphore' and 'stap_probe::clear_semaphore'. */ |
| |
| 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; |
| |
| /* Swallow errors. */ |
| if (target_read_memory (address, bytes, TYPE_LENGTH (type)) != 0) |
| { |
| warning (_("Could not read the value of a SystemTap semaphore.")); |
| return; |
| } |
| |
| enum bfd_endian byte_order = type_byte_order (type); |
| value = extract_unsigned_integer (bytes, TYPE_LENGTH (type), byte_order); |
| /* Note that we explicitly don't worry about overflow or |
| underflow. */ |
| if (set) |
| ++value; |
| else |
| --value; |
| |
| store_unsigned_integer (bytes, TYPE_LENGTH (type), byte_order, value); |
| |
| if (target_write_memory (address, bytes, TYPE_LENGTH (type)) != 0) |
| warning (_("Could not write the value of a SystemTap semaphore.")); |
| } |
| |
| /* Implementation of the 'set_semaphore' method. |
| |
| SystemTap semaphores act as reference counters, so calls to this |
| function must be paired with calls to 'clear_semaphore'. |
| |
| This function and 'clear_semaphore' race with another tool |
| changing the probes, but that is too rare to care. */ |
| |
| void |
| stap_probe::set_semaphore (struct objfile *objfile, struct gdbarch *gdbarch) |
| { |
| if (m_sem_addr == 0) |
| return; |
| stap_modify_semaphore (relocate_address (m_sem_addr, objfile), 1, gdbarch); |
| } |
| |
| /* Implementation of the 'clear_semaphore' method. */ |
| |
| void |
| stap_probe::clear_semaphore (struct objfile *objfile, struct gdbarch *gdbarch) |
| { |
| if (m_sem_addr == 0) |
| return; |
| stap_modify_semaphore (relocate_address (m_sem_addr, objfile), 0, gdbarch); |
| } |
| |
| /* Implementation of the 'get_static_ops' method. */ |
| |
| const static_probe_ops * |
| stap_probe::get_static_ops () const |
| { |
| return &stap_static_probe_ops; |
| } |
| |
| /* Implementation of the 'gen_info_probes_table_values' method. */ |
| |
| std::vector<const char *> |
| stap_probe::gen_info_probes_table_values () const |
| { |
| const char *val = NULL; |
| |
| if (m_sem_addr != 0) |
| val = print_core_address (this->get_gdbarch (), m_sem_addr); |
| |
| return std::vector<const char *> { val }; |
| } |
| |
| /* 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. */ |
| |
| static void |
| handle_stap_probe (struct objfile *objfile, struct sdt_note *el, |
| std::vector<std::unique_ptr<probe>> *probesp, |
| CORE_ADDR base) |
| { |
| bfd *abfd = objfile->obfd; |
| int size = bfd_get_arch_size (abfd) / 8; |
| struct gdbarch *gdbarch = objfile->arch (); |
| struct type *ptr_type = builtin_type (gdbarch)->builtin_data_ptr; |
| |
| /* Provider and the name of the probe. */ |
| const char *provider = (const char *) &el->data[3 * size]; |
| const char *name = ((const char *) |
| memchr (provider, '\0', |
| (char *) el->data + el->size - provider)); |
| /* Making sure there is a name. */ |
| if (name == NULL) |
| { |
| complaint (_("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 here makes sense. */ |
| return; |
| } |
| else |
| ++name; |
| |
| /* Retrieving the probe's address. */ |
| CORE_ADDR address = extract_typed_address (&el->data[0], ptr_type); |
| |
| /* Link-time sh_addr of `.stapsdt.base' section. */ |
| CORE_ADDR base_ref = extract_typed_address (&el->data[size], ptr_type); |
| |
| /* Semaphore address. */ |
| CORE_ADDR sem_addr = extract_typed_address (&el->data[2 * size], ptr_type); |
| |
| address += base - base_ref; |
| if (sem_addr != 0) |
| sem_addr += base - base_ref; |
| |
| /* Arguments. We can only extract the argument format if there is a valid |
| name for this probe. */ |
| const char *probe_args = ((const char*) |
| memchr (name, '\0', |
| (char *) el->data + el->size - name)); |
| |
| if (probe_args != NULL) |
| ++probe_args; |
| |
| if (probe_args == NULL |
| || (memchr (probe_args, '\0', (char *) el->data + el->size - name) |
| != el->data + el->size - 1)) |
| { |
| complaint (_("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. */ |
| return; |
| } |
| |
| stap_probe *ret = new stap_probe (std::string (name), std::string (provider), |
| address, gdbarch, sem_addr, probe_args); |
| |
| /* Successfully created probe. */ |
| probesp->emplace_back (ret); |
| } |
| |
| /* 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; |
| |
| for (asection *sect : gdb_bfd_sections (obfd)) |
| if ((sect->flags & (SEC_DATA | SEC_ALLOC | SEC_HAS_CONTENTS)) |
| && sect->name && !strcmp (sect->name, STAP_BASE_SECTION_NAME)) |
| ret = sect; |
| |
| if (ret == NULL) |
| { |
| complaint (_("could not obtain base address for " |
| "SystemTap section on objfile `%s'."), |
| bfd_get_filename (obfd)); |
| return 0; |
| } |
| |
| if (base != NULL) |
| *base = ret->vma; |
| |
| return 1; |
| } |
| |
| /* Implementation of the 'is_linespec' method. */ |
| |
| bool |
| stap_static_probe_ops::is_linespec (const char **linespecp) const |
| { |
| static const char *const keywords[] = { "-pstap", "-probe-stap", NULL }; |
| |
| return probe_is_linespec_by_keyword (linespecp, keywords); |
| } |
| |
| /* Implementation of the 'get_probes' method. */ |
| |
| void |
| stap_static_probe_ops::get_probes |
| (std::vector<std::unique_ptr<probe>> *probesp, |
| struct objfile *objfile) const |
| { |
| /* 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 = probesp->size (); |
| |
| 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 == probesp->size ()) |
| { |
| /* If we are here, it means we have failed to parse every known |
| probe. */ |
| complaint (_("could not parse SystemTap probe(s) from inferior")); |
| return; |
| } |
| } |
| |
| /* Implementation of the type_name method. */ |
| |
| const char * |
| stap_static_probe_ops::type_name () const |
| { |
| return "stap"; |
| } |
| |
| /* Implementation of the 'gen_info_probes_table_header' method. */ |
| |
| std::vector<struct info_probe_column> |
| stap_static_probe_ops::gen_info_probes_table_header () const |
| { |
| struct info_probe_column stap_probe_column; |
| |
| stap_probe_column.field_name = "semaphore"; |
| stap_probe_column.print_name = _("Semaphore"); |
| |
| return std::vector<struct info_probe_column> { stap_probe_column }; |
| } |
| |
| /* Implementation of the `info probes stap' command. */ |
| |
| static void |
| info_probes_stap_command (const char *arg, int from_tty) |
| { |
| info_probes_for_spops (arg, from_tty, &stap_static_probe_ops); |
| } |
| |
| void _initialize_stap_probe (); |
| void |
| _initialize_stap_probe () |
| { |
| all_static_probe_ops.push_back (&stap_static_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); |
| |
| 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 ()); |
| |
| |
| using namespace expr; |
| stap_maker_map[BINOP_ADD] = make_operation<add_operation>; |
| stap_maker_map[BINOP_BITWISE_AND] = make_operation<bitwise_and_operation>; |
| stap_maker_map[BINOP_BITWISE_IOR] = make_operation<bitwise_ior_operation>; |
| stap_maker_map[BINOP_BITWISE_XOR] = make_operation<bitwise_xor_operation>; |
| stap_maker_map[BINOP_DIV] = make_operation<div_operation>; |
| stap_maker_map[BINOP_EQUAL] = make_operation<equal_operation>; |
| stap_maker_map[BINOP_GEQ] = make_operation<geq_operation>; |
| stap_maker_map[BINOP_GTR] = make_operation<gtr_operation>; |
| stap_maker_map[BINOP_LEQ] = make_operation<leq_operation>; |
| stap_maker_map[BINOP_LESS] = make_operation<less_operation>; |
| stap_maker_map[BINOP_LOGICAL_AND] = make_operation<logical_and_operation>; |
| stap_maker_map[BINOP_LOGICAL_OR] = make_operation<logical_or_operation>; |
| stap_maker_map[BINOP_LSH] = make_operation<lsh_operation>; |
| stap_maker_map[BINOP_MUL] = make_operation<mul_operation>; |
| stap_maker_map[BINOP_NOTEQUAL] = make_operation<notequal_operation>; |
| stap_maker_map[BINOP_REM] = make_operation<rem_operation>; |
| stap_maker_map[BINOP_RSH] = make_operation<rsh_operation>; |
| stap_maker_map[BINOP_SUB] = make_operation<sub_operation>; |
| } |