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Re: [PATCH] gdb/riscv: Write 4-byte nop to dummy code region before inferior calls
- From: Pedro Alves <palves at redhat dot com>
- To: Andrew Burgess <andrew dot burgess at embecosm dot com>, gdb-patches at sourceware dot org
- Cc: Jim Wilson <jimw at sifive dot com>, Palmer Dabbelt <palmer at sifive dot com>, John Baldwin <jhb at freebsd dot org>
- Date: Fri, 19 Jul 2019 16:22:34 +0100
- Subject: Re: [PATCH] gdb/riscv: Write 4-byte nop to dummy code region before inferior calls
- References: <20190719105707.26806-1-andrew.burgess@embecosm.com>
Hi Andrew,
Just pointing out a few minor typos that jumped out at me when
I skimmed this.
On 7/19/19 11:57 AM, Andrew Burgess wrote:
> When making inferior function calls GDB sets up a dummy code region on
> the stack, and places a breakpoint within that region. If the random
> stack contents appear to be a compressed instruction then GDB will
> place a compressed instruction, which can cause problems if the target
"place a compressed breakpoint" I gather.
> doesn't support compressed instructions.
> index 7f3a1f6cbc3..817e76a423d 100644
> --- a/gdb/riscv-tdep.c
> +++ b/gdb/riscv-tdep.c
> @@ -1621,11 +1621,44 @@ riscv_push_dummy_code (struct gdbarch *gdbarch, CORE_ADDR sp,
> struct type *value_type, CORE_ADDR *real_pc,
> CORE_ADDR *bp_addr, struct regcache *regcache)
> {
> + /* A nop instruction is 'add x0, x0, 0'. */
> + static gdb_byte nop_insn[] = { 0x13, 0x00, 0x00, 0x00 };
static const
> +# Figure out where the breakpoint will be placed taking account for
> +# stack alignment, and alloction of the dummy code area.
Typo: "alloction".
Thanks,
Pedro Alves