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[PATCH v3 2/4] disasm: add struct disasm_insn to describe to-be-disassembled instruction
- From: Markus Metzger <markus dot t dot metzger at intel dot com>
- To: dje at google dot com
- Cc: gdb-patches at sourceware dot org, palves at redhat dot com
- Date: Tue, 27 Oct 2015 10:54:11 +0100
- Subject: [PATCH v3 2/4] disasm: add struct disasm_insn to describe to-be-disassembled instruction
- Authentication-results: sourceware.org; auth=none
- References: <1445939653-15126-1-git-send-email-markus dot t dot metzger at intel dot com>
The "record instruction-history" command prints for each instruction in
addition to the instruction's disassembly:
- the instruction number in the recorded execution trace
- a '?' before the instruction if it was executed speculatively
To allow the "record instruction-history" command to use GDB's disassembly
infrastructure, we extend gdb_pretty_print_insn to optionally print those
additional fields and export the function.
Add a new struct disasm_insn to add additional fields describing the
to-be-disassembled instruction. The additional fields are:
number an optional instruction number, zero if omitted.
is_speculative a predicate saying whether the instruction was
executed speculatively.
If non-zero, the instruction number is printed first. It will also appear
as a new optional field "insn-number" in MI. The field will be present if
insn_num is non-zero.
If is_speculative is set, speculative execution will be indicated by a "?"
following the new instruction number field. Unless the PC is omitted, it
will overwrite the first byte of the PC prefix. It will appear as a new
optional field "is-speculative" in MI. The field will contain "?" and will
be present if is_speculative is set.
The speculative execution indication is guarded by a new flag
DISASSEMBLY_SPECULATION.
Replace the PC parameter of gdb_pretty_print_insn with a pointer to the above
struct. GDB's "disassemble" command does not use the new fields.
2015-10-27 Markus Metzger <markus.t.metzger@intel.com>
gdb/
* disasm.h (DISASSEMBLY_SPECULATION): New.
(struct disasm_insn): New.
(gdb_pretty_print_insn): New.
* disasm.c (gdb_pretty_print_insn): Replace parameter PC with INSN.
Update users. Print instruction number and indicate speculative
execution, if requested.
---
gdb/disasm.c | 49 ++++++++++++++++++++++++++++++++++++++++---------
gdb/disasm.h | 23 +++++++++++++++++++++++
2 files changed, 63 insertions(+), 9 deletions(-)
diff --git a/gdb/disasm.c b/gdb/disasm.c
index 9b36bb6..2fffcdc 100644
--- a/gdb/disasm.c
+++ b/gdb/disasm.c
@@ -170,12 +170,12 @@ compare_lines (const void *mle1p, const void *mle2p)
return val;
}
-/* Prints the instruction at PC into UIOUT and returns the length of the
- printed instruction in bytes. */
+/* See disasm.h. */
-static int
+int
gdb_pretty_print_insn (struct gdbarch *gdbarch, struct ui_out *uiout,
- struct disassemble_info * di, CORE_ADDR pc, int flags,
+ struct disassemble_info * di,
+ const struct disasm_insn *insn, int flags,
struct ui_file *stb)
{
/* parts of the symbolic representation of the address */
@@ -186,10 +186,37 @@ gdb_pretty_print_insn (struct gdbarch *gdbarch, struct ui_out *uiout,
struct cleanup *ui_out_chain;
char *filename = NULL;
char *name = NULL;
+ CORE_ADDR pc;
ui_out_chain = make_cleanup_ui_out_tuple_begin_end (uiout, NULL);
+ pc = insn->addr;
+
+ if (insn->number != 0)
+ {
+ ui_out_field_fmt (uiout, "insn-number", "%u", insn->number);
+ ui_out_text (uiout, "\t");
+ }
- if ((flags & DISASSEMBLY_OMIT_PC) == 0)
+ if ((flags & DISASSEMBLY_SPECULATIVE) != 0)
+ {
+ if (insn->is_speculative)
+ {
+ ui_out_field_string (uiout, "is-speculative", "?");
+
+ /* The speculative execution indication overwrites the first
+ character of the PC prefix.
+ We assume a PC prefix length of 3 characters. */
+ if ((flags & DISASSEMBLY_OMIT_PC) == 0)
+ ui_out_text (uiout, pc_prefix (pc) + 1);
+ else
+ ui_out_text (uiout, " ");
+ }
+ else if ((flags & DISASSEMBLY_OMIT_PC) == 0)
+ ui_out_text (uiout, pc_prefix (pc));
+ else
+ ui_out_text (uiout, " ");
+ }
+ else if ((flags & DISASSEMBLY_OMIT_PC) == 0)
ui_out_text (uiout, pc_prefix (pc));
ui_out_field_core_addr (uiout, "address", gdbarch, pc);
@@ -262,25 +289,29 @@ dump_insns (struct gdbarch *gdbarch, struct ui_out *uiout,
int how_many, int flags, struct ui_file *stb,
CORE_ADDR *end_pc)
{
+ struct disasm_insn insn;
int num_displayed = 0;
- while (low < high && (how_many < 0 || num_displayed < how_many))
+ memset (&insn, 0, sizeof (insn));
+ insn.addr = low;
+
+ while (insn.addr < high && (how_many < 0 || num_displayed < how_many))
{
int size;
- size = gdb_pretty_print_insn (gdbarch, uiout, di, low, flags, stb);
+ size = gdb_pretty_print_insn (gdbarch, uiout, di, &insn, flags, stb);
if (size <= 0)
break;
++num_displayed;
- low += size;
+ insn.addr += size;
/* Allow user to bail out with ^C. */
QUIT;
}
if (end_pc != NULL)
- *end_pc = low;
+ *end_pc = insn.addr;
return num_displayed;
}
diff --git a/gdb/disasm.h b/gdb/disasm.h
index 7e6f1a2..32b64ff 100644
--- a/gdb/disasm.h
+++ b/gdb/disasm.h
@@ -27,11 +27,34 @@
#define DISASSEMBLY_FILENAME (0x1 << 3)
#define DISASSEMBLY_OMIT_PC (0x1 << 4)
#define DISASSEMBLY_SOURCE (0x1 << 5)
+#define DISASSEMBLY_SPECULATIVE (0x1 << 6)
struct gdbarch;
struct ui_out;
struct ui_file;
+/* An instruction to be disassembled. */
+
+struct disasm_insn
+{
+ /* The address of the memory containing the instruction. */
+ CORE_ADDR addr;
+
+ /* An optional instruction number. If non-zero, it is printed first. */
+ unsigned int number;
+
+ /* True if the instruction was executed speculatively. */
+ unsigned int is_speculative:1;
+};
+
+/* Prints the instruction INSN into UIOUT and returns the length of the
+ printed instruction in bytes. */
+
+extern int gdb_pretty_print_insn (struct gdbarch *gdbarch, struct ui_out *uiout,
+ struct disassemble_info * di,
+ const struct disasm_insn *insn, int flags,
+ struct ui_file *stb);
+
/* Return a filled in disassemble_info object for use by gdb. */
extern struct disassemble_info gdb_disassemble_info (struct gdbarch *gdbarch,
--
1.8.3.1