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-rw-r--r--gdb/ChangeLog12
-rw-r--r--gdb/gdbarch.c32
-rw-r--r--gdb/gdbarch.h30
-rwxr-xr-xgdb/gdbarch.sh25
-rw-r--r--gdb/i386-tdep.c29
-rw-r--r--gdb/stap-probe.c31
6 files changed, 156 insertions, 3 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a55c12a..d28471e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,17 @@
2019-06-28 Sergio Durigan Junior <sergiodj@redhat.com>
+ PR breakpoints/24541
+ * gdbarch.c: Regenerate.
+ * gdbarch.h: Regenerate.
+ * gdbarch.sh: Add 'stap_adjust_register'.
+ * i386-tdep.c: Include '<unordered_set>'.
+ (i386_stap_adjust_register): New function.
+ (i386_elf_init_abi): Register 'i386_stap_adjust_register'.
+ * stap-probe.c (stap_parse_register_operand): Call
+ 'gdbarch_stap_adjust_register'.
+
+2019-06-28 Sergio Durigan Junior <sergiodj@redhat.com>
+
PR python/24742
https://bugzilla.redhat.com/show_bug.cgi?id=1723564
* python/python.c (do_start_initialization): Use 'xmalloc'
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index a0c169d..cc7d0ac 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -324,6 +324,7 @@ struct gdbarch
const char * stap_gdb_register_suffix;
gdbarch_stap_is_single_operand_ftype *stap_is_single_operand;
gdbarch_stap_parse_special_token_ftype *stap_parse_special_token;
+ gdbarch_stap_adjust_register_ftype *stap_adjust_register;
gdbarch_dtrace_parse_probe_argument_ftype *dtrace_parse_probe_argument;
gdbarch_dtrace_probe_is_enabled_ftype *dtrace_probe_is_enabled;
gdbarch_dtrace_enable_probe_ftype *dtrace_enable_probe;
@@ -687,6 +688,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of stap_gdb_register_suffix, invalid_p == 0 */
/* Skip verify of stap_is_single_operand, has predicate. */
/* Skip verify of stap_parse_special_token, has predicate. */
+ /* Skip verify of stap_adjust_register, has predicate. */
/* Skip verify of dtrace_parse_probe_argument, has predicate. */
/* Skip verify of dtrace_probe_is_enabled, has predicate. */
/* Skip verify of dtrace_enable_probe, has predicate. */
@@ -1397,6 +1399,12 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
"gdbarch_dump: stack_frame_destroyed_p = <%s>\n",
host_address_to_string (gdbarch->stack_frame_destroyed_p));
fprintf_unfiltered (file,
+ "gdbarch_dump: gdbarch_stap_adjust_register_p() = %d\n",
+ gdbarch_stap_adjust_register_p (gdbarch));
+ fprintf_unfiltered (file,
+ "gdbarch_dump: stap_adjust_register = <%s>\n",
+ host_address_to_string (gdbarch->stap_adjust_register));
+ fprintf_unfiltered (file,
"gdbarch_dump: stap_gdb_register_prefix = %s\n",
pstring (gdbarch->stap_gdb_register_prefix));
fprintf_unfiltered (file,
@@ -4516,6 +4524,30 @@ set_gdbarch_stap_parse_special_token (struct gdbarch *gdbarch,
}
int
+gdbarch_stap_adjust_register_p (struct gdbarch *gdbarch)
+{
+ gdb_assert (gdbarch != NULL);
+ return gdbarch->stap_adjust_register != NULL;
+}
+
+void
+gdbarch_stap_adjust_register (struct gdbarch *gdbarch, struct stap_parse_info *p, std::string &regname, int regnum)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->stap_adjust_register != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_stap_adjust_register called\n");
+ gdbarch->stap_adjust_register (gdbarch, p, regname, regnum);
+}
+
+void
+set_gdbarch_stap_adjust_register (struct gdbarch *gdbarch,
+ gdbarch_stap_adjust_register_ftype stap_adjust_register)
+{
+ gdbarch->stap_adjust_register = stap_adjust_register;
+}
+
+int
gdbarch_dtrace_parse_probe_argument_p (struct gdbarch *gdbarch)
{
gdb_assert (gdbarch != NULL);
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 7ebd365a..0857d2f 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -1350,6 +1350,36 @@ typedef int (gdbarch_stap_parse_special_token_ftype) (struct gdbarch *gdbarch, s
extern int gdbarch_stap_parse_special_token (struct gdbarch *gdbarch, struct stap_parse_info *p);
extern void set_gdbarch_stap_parse_special_token (struct gdbarch *gdbarch, gdbarch_stap_parse_special_token_ftype *stap_parse_special_token);
+/* Perform arch-dependent adjustments to a register name.
+
+ In very specific situations, it may be necessary for the register
+ name present in a SystemTap probe's argument to be handled in a
+ special way. For example, on i386, GCC may over-optimize the
+ register allocation and use smaller registers than necessary. In
+ such cases, the client that is reading and evaluating the SystemTap
+ probe (ourselves) will need to actually fetch values from the wider
+ version of the register in question.
+
+ To illustrate the example, consider the following probe argument
+ (i386):
+
+ 4@%ax
+
+ This argument says that its value can be found at the %ax register,
+ which is a 16-bit register. However, the argument's prefix says
+ that its type is "uint32_t", which is 32-bit in size. Therefore, in
+ this case, GDB should actually fetch the probe's value from register
+ %eax, not %ax. In this scenario, this function would actually
+ replace the register name from %ax to %eax.
+
+ The rationale for this can be found at PR breakpoints/24541. */
+
+extern int gdbarch_stap_adjust_register_p (struct gdbarch *gdbarch);
+
+typedef void (gdbarch_stap_adjust_register_ftype) (struct gdbarch *gdbarch, struct stap_parse_info *p, std::string &regname, int regnum);
+extern void gdbarch_stap_adjust_register (struct gdbarch *gdbarch, struct stap_parse_info *p, std::string &regname, int regnum);
+extern void set_gdbarch_stap_adjust_register (struct gdbarch *gdbarch, gdbarch_stap_adjust_register_ftype *stap_adjust_register);
+
/* DTrace related functions.
The expression to compute the NARTGth+1 argument to a DTrace USDT probe.
NARG must be >= 0. */
diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 59493d8..f3d1bf4 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -1030,6 +1030,31 @@ M;int;stap_is_single_operand;const char *s;s
# parser), and should advance the buffer pointer (p->arg).
M;int;stap_parse_special_token;struct stap_parse_info *p;p
+# Perform arch-dependent adjustments to a register name.
+#
+# In very specific situations, it may be necessary for the register
+# name present in a SystemTap probe's argument to be handled in a
+# special way. For example, on i386, GCC may over-optimize the
+# register allocation and use smaller registers than necessary. In
+# such cases, the client that is reading and evaluating the SystemTap
+# probe (ourselves) will need to actually fetch values from the wider
+# version of the register in question.
+#
+# To illustrate the example, consider the following probe argument
+# (i386):
+#
+# 4@%ax
+#
+# This argument says that its value can be found at the %ax register,
+# which is a 16-bit register. However, the argument's prefix says
+# that its type is "uint32_t", which is 32-bit in size. Therefore, in
+# this case, GDB should actually fetch the probe's value from register
+# %eax, not %ax. In this scenario, this function would actually
+# replace the register name from %ax to %eax.
+#
+# The rationale for this can be found at PR breakpoints/24541.
+M;void;stap_adjust_register;struct stap_parse_info *p, std::string \&regname, int regnum;p, regname, regnum
+
# DTrace related functions.
# The expression to compute the NARTGth+1 argument to a DTrace USDT probe.
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index c542edf..00c1f8d 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -64,6 +64,7 @@
#include "parser-defs.h"
#include <ctype.h>
#include <algorithm>
+#include <unordered_set>
/* Register names. */
@@ -4385,6 +4386,32 @@ i386_stap_parse_special_token (struct gdbarch *gdbarch,
return 0;
}
+/* Implementation of 'gdbarch_stap_adjust_register', as defined in
+ gdbarch.h. */
+
+static void
+i386_stap_adjust_register (struct gdbarch *gdbarch, struct stap_parse_info *p,
+ std::string &regname, int regnum)
+{
+ static const std::unordered_set<std::string> reg_assoc
+ = { "ax", "bx", "cx", "dx",
+ "si", "di", "bp", "sp" };
+
+ if (register_size (gdbarch, regnum) >= TYPE_LENGTH (p->arg_type))
+ {
+ /* If we're dealing with a register whose size is greater or
+ equal than the size specified by the "[-]N@" prefix, then we
+ don't need to do anything. */
+ return;
+ }
+
+ if (reg_assoc.find (regname) != reg_assoc.end ())
+ {
+ /* Use the extended version of the register. */
+ regname = "e" + regname;
+ }
+}
+
/* gdbarch gnu_triplet_regexp method. Both arches are acceptable as GDB always
@@ -4433,6 +4460,8 @@ i386_elf_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
i386_stap_is_single_operand);
set_gdbarch_stap_parse_special_token (gdbarch,
i386_stap_parse_special_token);
+ set_gdbarch_stap_adjust_register (gdbarch,
+ i386_stap_adjust_register);
set_gdbarch_in_indirect_branch_thunk (gdbarch,
i386_in_indirect_branch_thunk);
diff --git a/gdb/stap-probe.c b/gdb/stap-probe.c
index e5a901b..aa1c814 100644
--- a/gdb/stap-probe.c
+++ b/gdb/stap-probe.c
@@ -762,13 +762,38 @@ stap_parse_register_operand (struct stap_parse_info *p)
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 (user_reg_map_name_to_regnum (gdbarch,
- regname.c_str (),
- regname.size ()) == -1)
+ 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 oldregname = regname;
+
+ gdbarch_stap_adjust_register (gdbarch, p, regname, regnum);
+
+ if (regname != oldregname)
+ {
+ /* 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, regname.c_str (),
+ regname.size ());
+
+ if (regnum == -1)
+ internal_error (__FILE__, __LINE__,
+ _("Invalid register name '%s' after replacing it"
+ " (previous name was '%s')"),
+ regname.c_str (), oldregname.c_str ());
+ }
+ }
+
write_exp_elt_opcode (&p->pstate, OP_REGISTER);
str.ptr = regname.c_str ();
str.length = regname.size ();
generated by cgit v1.1 at 2024-11-03 19:13:01 +0000