commit 08248ca9fe11040e9a4126cefebc5023d1d67222
Author: Sergio Durigan Junior <sergiodj@redhat.com>
Date: Sat Dec 28 14:14:11 2013 -0200
Implement SystemTap SDT probe support for AArch64
This commit implements the needed bits for SystemTap SDT probe support
on AArch64 architectures.
First, I started by looking at AArch64 assembly specification and
filling the necessary options on gdbarch's stap machinery in order to
make the generic asm parser (implemented in stap-probe.c) recognize
AArch64's asm.
After my last patch for the SystemTap SDT API, which extends it in order
to accept multiple prefixes and suffixes, this patch became simpler. I
also followed Marcus suggestion and did not shared code between 32- and
64-bit ARM.
Tom asked me in a previous message how I did my tests. I believe I
replied that, but just in case: I ran the tests on
gdb.base/stap-probe.exp by hand. I also managed to run the tests on
real hardware, and they pass without regressions.
2013-12-28 Sergio Durigan Junior <sergiodj@redhat.com>
PR tdep/15653
* NEWS: Mention SystemTap SDT probe support for AArch64 GNU/Linux.
* aarch64-linux-tdep.c: Include necessary headers for parsing of
SystemTap SDT probes.
(aarch64_stap_is_single_operand): New function.
(aarch64_stap_parse_special_token): Likewise.
(aarch64_linux_init_abi): Declare SystemTap SDT probe argument
prefixes and suffixes. Initialize gdbarch with them.
Index: gdb-7.6.1/gdb/NEWS
===================================================================
--- gdb-7.6.1.orig/gdb/NEWS
+++ gdb-7.6.1/gdb/NEWS
@@ -30,6 +30,8 @@ qXfer:libraries-svr4:read's annex
*** Changes in GDB 7.6
+* GDB now supports SystemTap SDT probes on AArch64 GNU/Linux.
+
* Target record has been renamed to record-full.
Record/replay is now enabled with the "record full" command.
This also affects settings that are associated with full record/replay
Index: gdb-7.6.1/gdb/aarch64-linux-tdep.c
===================================================================
--- gdb-7.6.1.orig/gdb/aarch64-linux-tdep.c
+++ gdb-7.6.1/gdb/aarch64-linux-tdep.c
@@ -35,6 +35,12 @@
#include "regcache.h"
#include "regset.h"
+#include "cli/cli-utils.h"
+#include "stap-probe.h"
+#include "parser-defs.h"
+#include "user-regs.h"
+#include <ctype.h>
+
/* The general-purpose regset consists of 31 X registers, plus SP, PC,
and PSTATE registers, as defined in the AArch64 port of the Linux
kernel. */
@@ -268,9 +274,129 @@ aarch64_linux_regset_from_core_section (
return NULL;
}
+/* Implementation of `gdbarch_stap_is_single_operand', as defined in
+ gdbarch.h. */
+
+static int
+aarch64_stap_is_single_operand (struct gdbarch *gdbarch, const char *s)
+{
+ return (*s == '#' || isdigit (*s) /* Literal number. */
+ || *s == '[' /* Register indirection. */
+ || isalpha (*s)); /* Register value. */
+}
+
+/* This routine is used to parse a special token in AArch64's assembly.
+
+ The special tokens parsed by it are:
+
+ - Register displacement (e.g, [fp, #-8])
+
+ It returns one if the special token has been parsed successfully,
+ or zero if the current token is not considered special. */
+
+static int
+aarch64_stap_parse_special_token (struct gdbarch *gdbarch,
+ struct stap_parse_info *p)
+{
+ if (*p->arg == '[')
+ {
+ /* Temporary holder for lookahead. */
+ const char *tmp = p->arg;
+ char *endp;
+ /* Used to save the register name. */
+ const char *start;
+ char *regname;
+ int len;
+ int got_minus = 0;
+ long displacement;
+ struct stoken str;
+
+ ++tmp;
+ start = tmp;
+
+ /* Register name. */
+ while (isalnum (*tmp))
+ ++tmp;
+
+ if (*tmp != ',')
+ return 0;
+
+ len = tmp - start;
+ regname = alloca (len + 2);
+
+ strncpy (regname, start, len);
+ regname[len] = '\0';
+
+ if (user_reg_map_name_to_regnum (gdbarch, regname, len) == -1)
+ error (_("Invalid register name `%s' on expression `%s'."),
+ regname, p->saved_arg);
+
+ ++tmp;
+ tmp = skip_spaces_const (tmp);
+ /* Now we expect a number. It can begin with '#' or simply
+ a digit. */
+ if (*tmp == '#')
+ ++tmp;
+
+ if (*tmp == '-')
+ {
+ ++tmp;
+ got_minus = 1;
+ }
+ else if (*tmp == '+')
+ ++tmp;
+
+ if (!isdigit (*tmp))
+ return 0;
+
+ displacement = strtol (tmp, &endp, 10);
+ tmp = endp;
+
+ /* Skipping last `]'. */
+ if (*tmp++ != ']')
+ return 0;
+
+ /* The displacement. */
+ write_exp_elt_opcode (OP_LONG);
+ write_exp_elt_type (builtin_type (gdbarch)->builtin_long);
+ write_exp_elt_longcst (displacement);
+ write_exp_elt_opcode (OP_LONG);
+ if (got_minus)
+ write_exp_elt_opcode (UNOP_NEG);
+
+ /* The register name. */
+ write_exp_elt_opcode (OP_REGISTER);
+ str.ptr = regname;
+ str.length = len;
+ write_exp_string (str);
+ write_exp_elt_opcode (OP_REGISTER);
+
+ write_exp_elt_opcode (BINOP_ADD);
+
+ /* Casting to the expected type. */
+ write_exp_elt_opcode (UNOP_CAST);
+ write_exp_elt_type (lookup_pointer_type (p->arg_type));
+ write_exp_elt_opcode (UNOP_CAST);
+
+ write_exp_elt_opcode (UNOP_IND);
+
+ p->arg = tmp;
+ }
+ else
+ return 0;
+
+ return 1;
+}
+
static void
aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
+ static const char *const stap_integer_prefixes[] = { "#", "", NULL };
+ static const char *const stap_register_prefixes[] = { "", NULL };
+ static const char *const stap_register_indirection_prefixes[] = { "[",
+ NULL };
+ static const char *const stap_register_indirection_suffixes[] = { "]",
+ NULL };
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
tdep->lowest_pc = 0x8000;
@@ -295,6 +421,17 @@ aarch64_linux_init_abi (struct gdbarch_i
set_gdbarch_regset_from_core_section (gdbarch,
aarch64_linux_regset_from_core_section);
+
+ /* SystemTap related. */
+ set_gdbarch_stap_integer_prefixes (gdbarch, stap_integer_prefixes);
+ set_gdbarch_stap_register_prefixes (gdbarch, stap_register_prefixes);
+ set_gdbarch_stap_register_indirection_prefixes (gdbarch,
+ stap_register_indirection_prefixes);
+ set_gdbarch_stap_register_indirection_suffixes (gdbarch,
+ stap_register_indirection_suffixes);
+ set_gdbarch_stap_is_single_operand (gdbarch, aarch64_stap_is_single_operand);
+ set_gdbarch_stap_parse_special_token (gdbarch,
+ aarch64_stap_parse_special_token);
}
/* Provide a prototype to silence -Wmissing-prototypes. */