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[PATCH 2/8] Make aarch64_decode_adrp handle both ADR and ADRP instructions
- From: Yao Qi <qiyaoltc at gmail dot com>
- To: gdb-patches at sourceware dot org
- Date: Fri, 18 Sep 2015 13:42:58 +0100
- Subject: [PATCH 2/8] Make aarch64_decode_adrp handle both ADR and ADRP instructions
- Authentication-results: sourceware.org; auth=none
- References: <1442230282-20751-1-git-send-email-pierre dot langlois at arm dot com> <1442580184-22562-1-git-send-email-yao dot qi at linaro dot org>
From: Pierre Langlois <pierre.langlois@arm.com>
We will need to decode both ADR and ADRP instructions in GDBserver.
This patch makes common code handle both cases, even if GDB only needs
to decode the ADRP instruction.
gdb/ChangeLog:
* aarch64-tdep.c (aarch64_analyze_prologue): New is_adrp
variable. Call aarch64_decode_adr instead of
aarch64_decode_adrp.
* arch/aarch64-insn.h (aarch64_decode_adrp): Delete.
(aarch64_decode_adr): New function declaration.
* arch/aarch64-insn.c (aarch64_decode_adrp): Delete.
(aarch64_decode_adr): New function, factored out from
aarch64_decode_adrp to decode both adr and adrp instructions.
---
gdb/aarch64-tdep.c | 4 +++-
gdb/arch/aarch64-insn.c | 29 ++++++++++++++++++++++++-----
gdb/arch/aarch64-insn.h | 3 ++-
3 files changed, 29 insertions(+), 7 deletions(-)
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 92e2404..da61e54 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -551,13 +551,15 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
int is_cbnz;
int is_tbnz;
unsigned bit;
+ int is_adrp;
int32_t offset;
insn = read_memory_unsigned_integer (start, 4, byte_order_for_code);
if (aarch64_decode_add_sub_imm (start, insn, &rd, &rn, &imm))
regs[rd] = pv_add_constant (regs[rn], imm);
- else if (aarch64_decode_adrp (start, insn, &rd))
+ else if (aarch64_decode_adr (start, insn, &is_adrp, &rd, &offset)
+ && is_adrp)
regs[rd] = pv_unknown ();
else if (aarch64_decode_b (start, insn, &is_link, &offset))
{
diff --git a/gdb/arch/aarch64-insn.c b/gdb/arch/aarch64-insn.c
index 3a289a2..13d0013 100644
--- a/gdb/arch/aarch64-insn.c
+++ b/gdb/arch/aarch64-insn.c
@@ -55,25 +55,44 @@ decode_masked_match (uint32_t insn, uint32_t mask, uint32_t pattern)
return (insn & mask) == pattern;
}
-/* Decode an opcode if it represents an ADRP instruction.
+/* Decode an opcode if it represents an ADR or ADRP instruction.
ADDR specifies the address of the opcode.
INSN specifies the opcode to test.
+ IS_ADRP receives the 'op' field from the decoded instruction.
RD receives the 'rd' field from the decoded instruction.
+ OFFSET receives the 'immhi:immlo' field from the decoded instruction.
Return 1 if the opcodes matches and is decoded, otherwise 0. */
int
-aarch64_decode_adrp (CORE_ADDR addr, uint32_t insn, unsigned *rd)
+aarch64_decode_adr (CORE_ADDR addr, uint32_t insn, int *is_adrp,
+ unsigned *rd, int32_t *offset)
{
- if (decode_masked_match (insn, 0x9f000000, 0x90000000))
+ /* adr 0ii1 0000 iiii iiii iiii iiii iiir rrrr */
+ /* adrp 1ii1 0000 iiii iiii iiii iiii iiir rrrr */
+ if (decode_masked_match (insn, 0x1f000000, 0x10000000))
{
+ uint32_t immlo = (insn >> 29) & 0x3;
+ int32_t immhi = extract_signed_bitfield (insn, 19, 5) << 2;
+
+ *is_adrp = (insn >> 31) & 0x1;
*rd = (insn >> 0) & 0x1f;
+ if (*is_adrp)
+ {
+ /* The ADRP instruction has an offset with a -/+ 4GB range,
+ encoded as (immhi:immlo * 4096). */
+ *offset = (immhi | immlo) * 4096;
+ }
+ else
+ *offset = (immhi | immlo);
+
if (aarch64_debug)
{
- debug_printf ("decode: 0x%s 0x%x adrp x%u, #?\n",
- core_addr_to_string_nz (addr), insn, *rd);
+ debug_printf ("decode: 0x%s 0x%x %s x%u, #?\n",
+ core_addr_to_string_nz (addr), insn,
+ *is_adrp ? "adrp" : "adr", *rd);
}
return 1;
}
diff --git a/gdb/arch/aarch64-insn.h b/gdb/arch/aarch64-insn.h
index 7775a34..2facb44 100644
--- a/gdb/arch/aarch64-insn.h
+++ b/gdb/arch/aarch64-insn.h
@@ -21,7 +21,8 @@
extern int aarch64_debug;
-int aarch64_decode_adrp (CORE_ADDR addr, uint32_t insn, unsigned *rd);
+int aarch64_decode_adr (CORE_ADDR addr, uint32_t insn, int *is_adrp,
+ unsigned *rd, int32_t *offset);
int aarch64_decode_b (CORE_ADDR addr, uint32_t insn, int *is_bl,
int32_t *offset);
--
1.9.1