gdbarch: add instruction predicate methods

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.

2014-01-16  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.

1 files changed, 59 insertions, 0 deletions

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);