[PATCH v2 06/17] arm-tdep.c: Use relocation visitor in Thumb 16-bits instruction decoding

Antoine Tremblay
2016-06-09T12:56:49Z

This is the same as the previous patch, but for the 16-bits Thumb
instructions.

gdb/ChangeLog:

* arm-tdep.c (thumb_16bit_insn_reloc_visitor): New.
(thumb_decode_pc_relative_16bit): Add visitor parameter and use
it.
(thumb_16bit_relocate_insn): Add and use visitor parameter.
(thumb_16bit_insn_reloc_visitor): New.
(arm_process_displaced_insn): Pass
thumb_16it_insn_reloc_visitor to thumb_16bit_relocate_insn.
---
gdb/arm-tdep.c | 81 +++++++++++++++++++++++++++++++++++++++++-----------------
1 file changed, 57 insertions(+), 24 deletions(-)

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 6a9d110..0f35eb3 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -4529,6 +4529,21 @@ struct thumb_32bit_insn_reloc_visitor
struct arm_insn_reloc_data *data);
};

+struct thumb_16bit_insn_reloc_visitor
+{
+ int (*alu_reg) (uint16_t insn, struct arm_insn_reloc_data *data);
+ int (*b) (uint16_t insn, struct arm_insn_reloc_data *data);
+ int (*bx_blx_reg) (uint16_t insn, struct arm_insn_reloc_data *data);
+ int (*cbnz_cbz) (uint16_t insn1, struct arm_insn_reloc_data *data);
+ int (*load_literal) (uint16_t insn1, struct arm_insn_reloc_data *data);
+ int (*others) (uint16_t insn, const char *iname,
+ struct arm_insn_reloc_data *data);
+ int (*pc_relative_16bit) (uint16_t insn, struct arm_insn_reloc_data *data,
+ int rd, unsigned int imm);
+ int (*pop_pc_16bit) (uint16_t insn, struct arm_insn_reloc_data *data);
+ int (*svc) (uint16_t insn, struct arm_insn_reloc_data *data);
+};
+
/* Helper for register reads for displaced stepping. In particular, this
returns the PC as it would be seen by the instruction at its original
location. */
@@ -7050,12 +7065,14 @@ thumb_copy_pc_relative_16bit (uint16_t insn, struct arm_insn_reloc_data *data,
}

static int
-thumb_decode_pc_relative_16bit (uint16_t insn, struct arm_insn_reloc_data *data)
+thumb_decode_pc_relative_16bit (uint16_t insn,
+ struct thumb_16bit_insn_reloc_visitor *visitor,
+ struct arm_insn_reloc_data *data)
{
unsigned int rd = bits (insn, 8, 10);
unsigned int imm8 = bits (insn, 0, 7);

- return thumb_copy_pc_relative_16bit (insn, data, rd, imm8);
+ return visitor->pc_relative_16bit (insn, data, rd, imm8);
}

static int
@@ -7320,7 +7337,9 @@ thumb_copy_pop_pc_16bit (uint16_t insn1, struct arm_insn_reloc_data *data)
}

static int
-thumb_16bit_relocate_insn (uint16_t insn1, struct arm_insn_reloc_data *data)
+thumb_16bit_relocate_insn (uint16_t insn1,
+ struct thumb_16bit_insn_reloc_visitor *visitor,
+ struct arm_insn_reloc_data *data)
{
unsigned short op_bit_12_15 = bits (insn1, 12, 15);
unsigned short op_bit_10_11 = bits (insn1, 10, 11);
@@ -7331,79 +7350,79 @@ thumb_16bit_relocate_insn (uint16_t insn1, struct arm_insn_reloc_data *data)
{
/* Shift (imme), add, subtract, move and compare. */
case 0: case 1: case 2: case 3:
- err = thumb_copy_unmodified_16bit (insn1, "shift/add/sub/mov/cmp", data);
+ err = visitor->others (insn1, "shift/add/sub/mov/cmp", data);
break;
case 4:
switch (op_bit_10_11)
{
case 0: /* Data-processing */
- err = thumb_copy_unmodified_16bit (insn1, "data-processing", data);
+ err = visitor->others (insn1, "data-processing", data);
break;
case 1: /* Special data instructions and branch and exchange. */
{
unsigned short op = bits (insn1, 7, 9);
if (op == 6 || op == 7) /* BX or BLX */
- err = thumb_copy_bx_blx_reg (insn1, data);
+ err = visitor->bx_blx_reg (insn1, data);
else if (bits (insn1, 6, 7) != 0) /* ADD/MOV/CMP high registers. */
- err = thumb_copy_alu_reg (insn1, data);
+ err = visitor->alu_reg (insn1, data);
else
- err = thumb_copy_unmodified_16bit (insn1, "special data", data);
+ err = visitor->others (insn1, "special data", data);
}
break;
default: /* LDR (literal) */
- err = thumb_copy_16bit_ldr_literal (insn1, data);
+ err = visitor->load_literal (insn1, data);
}
break;
case 5: case 6: case 7: case 8: case 9: /* Load/Store single data item */
- err = thumb_copy_unmodified_16bit (insn1, "ldr/str", data);
+ err = visitor->others (insn1, "ldr/str", data);
break;
case 10:
if (op_bit_10_11 < 2) /* Generate PC-relative address */
- err = thumb_decode_pc_relative_16bit (insn1, data);
+ err = thumb_decode_pc_relative_16bit (insn1, visitor, data);
else /* Generate SP-relative address */
- err = thumb_copy_unmodified_16bit (insn1, "sp-relative", data);
+ err = visitor->others (insn1, "sp-relative", data);
break;
case 11: /* Misc 16-bit instructions */
{
switch (bits (insn1, 8, 11))
{
case 1: case 3: case 9: case 11: /* CBNZ, CBZ */
- err = thumb_copy_cbnz_cbz (insn1, data);
+ err = visitor->cbnz_cbz (insn1, data);
break;
case 12: case 13: /* POP */
if (bit (insn1, 8)) /* PC is in register list. */
- err = thumb_copy_pop_pc_16bit (insn1, data);
+ err = visitor->pop_pc_16bit (insn1, data);
else
- err = thumb_copy_unmodified_16bit (insn1, "pop", data);
+ err = visitor->others (insn1, "pop", data);
break;
case 15: /* If-Then, and hints */
if (bits (insn1, 0, 3))
/* If-Then makes up to four following instructions conditional.
IT instruction itself is not conditional, so handle it as a
common unmodified instruction. */
- err = thumb_copy_unmodified_16bit (insn1, "If-Then", data);
+ err = visitor->others (insn1, "If-Then", data);
else
- err = thumb_copy_unmodified_16bit (insn1, "hints", data);
+ err = visitor->others (insn1, "hints", data);
break;
default:
- err = thumb_copy_unmodified_16bit (insn1, "misc", data);
+ err = visitor->others (insn1, "misc", data);
}
}
break;
case 12:
if (op_bit_10_11 < 2) /* Store multiple registers */
- err = thumb_copy_unmodified_16bit (insn1, "stm", data);
+ err = visitor->others (insn1, "stm", data);
else /* Load multiple registers */
- err = thumb_copy_unmodified_16bit (insn1, "ldm", data);
+ err = visitor->others (insn1, "ldm", data);
break;
case 13: /* Conditional branch and supervisor call */
if (bits (insn1, 9, 11) != 7) /* conditional branch */
- err = thumb_copy_b (insn1, data);
+ err = visitor->b (insn1, data);
else
- err = thumb_copy_svc (insn1, data);
+ err = visitor->svc (insn1, data);
break;
case 14: /* Unconditional branch */
- err = thumb_copy_b (insn1, data);
+ err = visitor->b (insn1, data);
break;
default:
err = 1;
@@ -7663,6 +7682,19 @@ static struct thumb_32bit_insn_reloc_visitor thumb_32bit_insn_reloc_visitor =
thumb_32bit_copy_undef,
};

+static struct thumb_16bit_insn_reloc_visitor thumb_16bit_insn_reloc_visitor =
+{
+ thumb_copy_alu_reg,
+ thumb_copy_b,
+ thumb_copy_bx_blx_reg,
+ thumb_copy_cbnz_cbz,
+ thumb_copy_16bit_ldr_literal,
+ thumb_copy_unmodified_16bit,
+ thumb_copy_pc_relative_16bit,
+ thumb_copy_pop_pc_16bit,
+ thumb_copy_svc,
+};
+
void
arm_process_displaced_insn (struct gdbarch *gdbarch, CORE_ADDR from,
CORE_ADDR to, struct regcache *regs,
@@ -7722,7 +7754,8 @@ arm_process_displaced_insn (struct gdbarch *gdbarch, CORE_ADDR from,
&reloc_data);
}
else
- err = thumb_16bit_relocate_insn (insn1, &reloc_data);
+ err = thumb_16bit_relocate_insn (insn1, &thumb_16bit_insn_reloc_visitor,
+ &reloc_data);
}

if (err)
--
2.8.1