[PATCH v10 04/28] gdbarch: add instruction predicate methods

Markus Metzger
2014-01-14T08:05:19Z

Add new methods to gdbarch for analyzing the instruction at a given address.
Implement those methods for i386 and amd64 architectures.

This is needed by "record btrace" to detect function calls in the
execution trace.

2014-01-14 Markus Metzger <markus.t.metzger@intel.com>

* amd64-tdep.c (amd64_classify_insn_at, amd64_insn_is_call)
(amd64_insn_is_ret, amd64_insn_is_jump, amd64_jmp_p): New.
(amd64_init_abi): Add insn_is_call, insn_is_ret, and insn_is_jump
to gdbarch.
* i386-tdep.c (i386_insn_is_call, i386_insn_is_ret)
(i386_insn_is_jump, i386_jmp_p): New.
(i386_gdbarch_init): Add insn_is_call, insn_is_ret, and
insn_is_jump to gdbarch.
* gdbarch.sh (insn_is_call, insn_is_ret, insn_is_jump): New.
* gdbarch.h: Regenerated.
* gdbarch.c: Regenerated.
* arch-utils.h (default_insn_is_call, default_insn_is_ret)
(default_insn_is_jump): New.
* arch-utils.c (default_insn_is_call, default_insn_is_ret)
(default_insn_is_jump): New.

---
gdb/amd64-tdep.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/arch-utils.c | 15 ++++++++++++
gdb/arch-utils.h | 4 ++++
gdb/gdbarch.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/gdbarch.h | 18 ++++++++++++++
gdb/gdbarch.sh | 9 +++++++
gdb/i386-tdep.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++
7 files changed, 244 insertions(+)

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index 2055a3b..72d748e 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -1345,6 +1345,24 @@ amd64_absolute_jmp_p (const struct amd64_insn *details)
return 0;
}

+/* Return non-zero if the instruction DETAILS is a jump, zero otherwise. */
+
+static int
+amd64_jmp_p (const struct amd64_insn *details)
+{
+ const gdb_byte *insn = &details->raw_insn[details->opcode_offset];
+
+ /* jump short, relative. */
+ if (insn[0] == 0xeb)
+ return 1;
+
+ /* jump near, relative. */
+ if (insn[0] == 0xe9)
+ return 1;
+
+ return amd64_absolute_jmp_p (details);
+}
+
static int
amd64_absolute_call_p (const struct amd64_insn *details)
{
@@ -1416,6 +1434,52 @@ amd64_syscall_p (const struct amd64_insn *details, int *lengthp)
return 0;
}

+/* Classify the instruction at ADDR using PRED.
+ Throw an error if the memory can't be read. */
+
+static int
+amd64_classify_insn_at (struct gdbarch *gdbarch, CORE_ADDR addr,
+ int (*pred) (const struct amd64_insn *))
+{
+ struct amd64_insn details;
+ gdb_byte *buf;
+ int len, classification;
+
+ len = gdbarch_max_insn_length (gdbarch);
+ buf = alloca (len);
+
+ read_code (addr, buf, len);
+ amd64_get_insn_details (buf, &details);
+
+ classification = pred (&details);
+
+ return classification;
+}
+
+/* The gdbarch insn_is_call method. */
+
+static int
+amd64_insn_is_call (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ return amd64_classify_insn_at (gdbarch, addr, amd64_call_p);
+}
+
+/* The gdbarch insn_is_ret method. */
+
+static int
+amd64_insn_is_ret (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ return amd64_classify_insn_at (gdbarch, addr, amd64_ret_p);
+}
+
+/* The gdbarch insn_is_jump method. */
+
+static int
+amd64_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ return amd64_classify_insn_at (gdbarch, addr, amd64_jmp_p);
+}
+
/* Fix up the state of registers and memory after having single-stepped
a displaced instruction. */

@@ -2966,6 +3030,9 @@ amd64_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_insn_is_call (gdbarch, amd64_insn_is_call);
+ set_gdbarch_insn_is_ret (gdbarch, amd64_insn_is_ret);
+ set_gdbarch_insn_is_jump (gdbarch, amd64_insn_is_jump);
}
\f

diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index 66cebd7..bff1a10 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -804,6 +804,21 @@ default_return_in_first_hidden_param_p (struct gdbarch *gdbarch,
return language_pass_by_reference (type);
}

+int default_insn_is_call (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ return 0;
+}
+
+int default_insn_is_ret (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ return 0;
+}
+
+int default_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ return 0;
+}
+
/* */

/* -Wmissing-prototypes */
diff --git a/gdb/arch-utils.h b/gdb/arch-utils.h
index 08ad4f9..46d1573 100644
--- a/gdb/arch-utils.h
+++ b/gdb/arch-utils.h
@@ -170,4 +170,8 @@ extern const char *default_auto_wide_charset (void);

extern int default_return_in_first_hidden_param_p (struct gdbarch *,
struct type *);
+
+extern int default_insn_is_call (struct gdbarch *, CORE_ADDR);
+extern int default_insn_is_ret (struct gdbarch *, CORE_ADDR);
+extern int default_insn_is_jump (struct gdbarch *, CORE_ADDR);
#endif
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index 694fc0d..e16b8d0 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -317,6 +317,9 @@ struct gdbarch
gdbarch_core_info_proc_ftype *core_info_proc;
gdbarch_iterate_over_objfiles_in_search_order_ftype *iterate_over_objfiles_in_search_order;
struct ravenscar_arch_ops * ravenscar_ops;
+ gdbarch_insn_is_call_ftype *insn_is_call;
+ gdbarch_insn_is_ret_ftype *insn_is_ret;
+ gdbarch_insn_is_jump_ftype *insn_is_jump;
};

@@ -490,6 +493,9 @@ struct gdbarch startup_gdbarch =
0, /* core_info_proc */
default_iterate_over_objfiles_in_search_order, /* iterate_over_objfiles_in_search_order */
NULL, /* ravenscar_ops */
+ default_insn_is_call, /* insn_is_call */
+ default_insn_is_ret, /* insn_is_ret */
+ default_insn_is_jump, /* insn_is_jump */
/* startup_gdbarch() */
};

@@ -581,6 +587,9 @@ gdbarch_alloc (const struct gdbarch_info *info,
gdbarch->gen_return_address = default_gen_return_address;
gdbarch->iterate_over_objfiles_in_search_order = default_iterate_over_objfiles_in_search_order;
gdbarch->ravenscar_ops = NULL;
+ gdbarch->insn_is_call = default_insn_is_call;
+ gdbarch->insn_is_ret = default_insn_is_ret;
+ gdbarch->insn_is_jump = default_insn_is_jump;
/* gdbarch_alloc() */

return gdbarch;
@@ -795,6 +804,9 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of core_info_proc, has predicate. */
/* Skip verify of iterate_over_objfiles_in_search_order, invalid_p == 0 */
/* Skip verify of ravenscar_ops, invalid_p == 0 */
+ /* Skip verify of insn_is_call, invalid_p == 0 */
+ /* Skip verify of insn_is_ret, invalid_p == 0 */
+ /* Skip verify of insn_is_jump, invalid_p == 0 */
buf = ui_file_xstrdup (log, &length);
make_cleanup (xfree, buf);
if (length > 0)
@@ -1128,6 +1140,15 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
"gdbarch_dump: inner_than = <%s>\n",
host_address_to_string (gdbarch->inner_than));
fprintf_unfiltered (file,
+ "gdbarch_dump: insn_is_call = <%s>\n",
+ host_address_to_string (gdbarch->insn_is_call));
+ fprintf_unfiltered (file,
+ "gdbarch_dump: insn_is_jump = <%s>\n",
+ host_address_to_string (gdbarch->insn_is_jump));
+ fprintf_unfiltered (file,
+ "gdbarch_dump: insn_is_ret = <%s>\n",
+ host_address_to_string (gdbarch->insn_is_ret));
+ fprintf_unfiltered (file,
"gdbarch_dump: int_bit = %s\n",
plongest (gdbarch->int_bit));
fprintf_unfiltered (file,
@@ -4451,6 +4472,57 @@ set_gdbarch_ravenscar_ops (struct gdbarch *gdbarch,
gdbarch->ravenscar_ops = ravenscar_ops;
}

+int
+gdbarch_insn_is_call (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->insn_is_call != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_insn_is_call called\n");
+ return gdbarch->insn_is_call (gdbarch, addr);
+}
+
+void
+set_gdbarch_insn_is_call (struct gdbarch *gdbarch,
+ gdbarch_insn_is_call_ftype insn_is_call)
+{
+ gdbarch->insn_is_call = insn_is_call;
+}
+
+int
+gdbarch_insn_is_ret (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->insn_is_ret != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_insn_is_ret called\n");
+ return gdbarch->insn_is_ret (gdbarch, addr);
+}
+
+void
+set_gdbarch_insn_is_ret (struct gdbarch *gdbarch,
+ gdbarch_insn_is_ret_ftype insn_is_ret)
+{
+ gdbarch->insn_is_ret = insn_is_ret;
+}
+
+int
+gdbarch_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->insn_is_jump != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_insn_is_jump called\n");
+ return gdbarch->insn_is_jump (gdbarch, addr);
+}
+
+void
+set_gdbarch_insn_is_jump (struct gdbarch *gdbarch,
+ gdbarch_insn_is_jump_ftype insn_is_jump)
+{
+ gdbarch->insn_is_jump = insn_is_jump;
+}
+

/* Keep a registry of per-architecture data-pointers required by GDB
modules. */
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index ccb7e96..c4b5bac 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -1267,6 +1267,24 @@ extern void set_gdbarch_iterate_over_objfiles_in_search_order (struct gdbarch *g
extern struct ravenscar_arch_ops * gdbarch_ravenscar_ops (struct gdbarch *gdbarch);
extern void set_gdbarch_ravenscar_ops (struct gdbarch *gdbarch, struct ravenscar_arch_ops * ravenscar_ops);

+/* Return non-zero if the instruction at ADDR is a call; zero otherwise. */
+
+typedef int (gdbarch_insn_is_call_ftype) (struct gdbarch *gdbarch, CORE_ADDR addr);
+extern int gdbarch_insn_is_call (struct gdbarch *gdbarch, CORE_ADDR addr);
+extern void set_gdbarch_insn_is_call (struct gdbarch *gdbarch, gdbarch_insn_is_call_ftype *insn_is_call);
+
+/* Return non-zero if the instruction at ADDR is a return; zero otherwise. */
+
+typedef int (gdbarch_insn_is_ret_ftype) (struct gdbarch *gdbarch, CORE_ADDR addr);
+extern int gdbarch_insn_is_ret (struct gdbarch *gdbarch, CORE_ADDR addr);
+extern void set_gdbarch_insn_is_ret (struct gdbarch *gdbarch, gdbarch_insn_is_ret_ftype *insn_is_ret);
+
+/* Return non-zero if the instruction at ADDR is a jump; zero otherwise. */
+
+typedef int (gdbarch_insn_is_jump_ftype) (struct gdbarch *gdbarch, CORE_ADDR addr);
+extern int gdbarch_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr);
+extern void set_gdbarch_insn_is_jump (struct gdbarch *gdbarch, gdbarch_insn_is_jump_ftype *insn_is_jump);
+
/* Definition for an unknown syscall, used basically in error-cases. */
#define UNKNOWN_SYSCALL (-1)

diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index ec54d6f..57bf0e7 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -994,6 +994,15 @@ m:void:iterate_over_objfiles_in_search_order:iterate_over_objfiles_in_search_ord

# Ravenscar arch-dependent ops.
v:struct ravenscar_arch_ops *:ravenscar_ops:::NULL:NULL::0:host_address_to_string (gdbarch->ravenscar_ops)
+
+# Return non-zero if the instruction at ADDR is a call; zero otherwise.
+m:int:insn_is_call:CORE_ADDR addr:addr::default_insn_is_call::0
+
+# Return non-zero if the instruction at ADDR is a return; zero otherwise.
+m:int:insn_is_ret:CORE_ADDR addr:addr::default_insn_is_ret::0
+
+# Return non-zero if the instruction at ADDR is a jump; zero otherwise.
+m:int:insn_is_jump:CORE_ADDR addr:addr::default_insn_is_jump::0
EOF
}

diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 4a5f652..57f18cb 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -530,6 +530,22 @@ i386_absolute_jmp_p (const gdb_byte *insn)
return 0;
}

+/* Return non-zero if INSN is a jump, zero otherwise. */
+
+static int
+i386_jmp_p (const gdb_byte *insn)
+{
+ /* jump short, relative. */
+ if (insn[0] == 0xeb)
+ return 1;
+
+ /* jump near, relative. */
+ if (insn[0] == 0xe9)
+ return 1;
+
+ return i386_absolute_jmp_p (insn);
+}
+
static int
i386_absolute_call_p (const gdb_byte *insn)
{
@@ -601,6 +617,45 @@ i386_syscall_p (const gdb_byte *insn, int *lengthp)
return 0;
}

+/* The gdbarch insn_is_call method. */
+
+static int
+i386_insn_is_call (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ gdb_byte buf[I386_MAX_INSN_LEN], *insn;
+
+ read_code (addr, buf, I386_MAX_INSN_LEN);
+ insn = i386_skip_prefixes (buf, I386_MAX_INSN_LEN);
+
+ return i386_call_p (insn);
+}
+
+/* The gdbarch insn_is_ret method. */
+
+static int
+i386_insn_is_ret (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ gdb_byte buf[I386_MAX_INSN_LEN], *insn;
+
+ read_code (addr, buf, I386_MAX_INSN_LEN);
+ insn = i386_skip_prefixes (buf, I386_MAX_INSN_LEN);
+
+ return i386_ret_p (insn);
+}
+
+/* The gdbarch insn_is_jump method. */
+
+static int
+i386_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
+{
+ gdb_byte buf[I386_MAX_INSN_LEN], *insn;
+
+ read_code (addr, buf, I386_MAX_INSN_LEN);
+ insn = i386_skip_prefixes (buf, I386_MAX_INSN_LEN);
+
+ return i386_jmp_p (insn);
+}
+
/* Some kernels may run one past a syscall insn, so we have to cope.
Otherwise this is just simple_displaced_step_copy_insn. */

@@ -8017,6 +8072,10 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)

set_gdbarch_gen_return_address (gdbarch, i386_gen_return_address);

+ set_gdbarch_insn_is_call (gdbarch, i386_insn_is_call);
+ set_gdbarch_insn_is_ret (gdbarch, i386_insn_is_ret);
+ set_gdbarch_insn_is_jump (gdbarch, i386_insn_is_jump);
+
/* Hook in ABI-specific overrides, if they have been registered. */
info.tdep_info = (void *) tdesc_data;
gdbarch_init_osabi (info, gdbarch);
--
1.8.3.1