From: Simon Marchi <simon.marchi@polymtl.ca>
To: Simon Marchi <simon.marchi@ericsson.com>
Cc: gdb-patches@sourceware.org, Tom Tromey <tom@tromey.com>
Subject: Re: [PATCH] compile-loc2c: Fix uninitialized variable error
Date: Sun, 25 Jun 2017 17:24:00 -0000 [thread overview]
Message-ID: <3ec2d2df8170bea2b43c095996ad7278@polymtl.ca> (raw)
In-Reply-To: <1497124148-11187-1-git-send-email-simon.marchi@ericsson.com>
On 2017-06-10 21:49, Simon Marchi wrote:
> Compiling with clang gives this warning/error:
>
> /home/emaisin/src/binutils-gdb/gdb/compile/compile-loc2c.c:731:6:
> error: variable 'uoffset' is uninitialized when used here
> [-Werror,-Wuninitialized]
> uoffset += dwarf2_per_cu_text_offset (per_cu);
> ^~~~~~~
> /home/emaisin/src/binutils-gdb/gdb/compile/compile-loc2c.c:669:23:
> note: initialize the variable 'uoffset' to silence this warning
> uint64_t uoffset, reg;
> ^
> = 0
>
> I am really not sure if what this patch does is good, but it is my best
> guess. DW_OP_addr means that there's an constant address provided by
> the DWARF bytecode that should be pushed on the stack. That address is
> considered skipped by the "op_ptr += addr_size", but it is never read.
> uoffset is indeed read just after, without having been assigned first.
>
> So I think the intent is to read the address, it was just omitted.
>
> gdb/ChangeLog:
>
> * compile/compile-loc2c.c (do_compile_dwarf_expr_to_c): Read
> address when op is DW_OP_addr.
> ---
> gdb/compile/compile-loc2c.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/gdb/compile/compile-loc2c.c b/gdb/compile/compile-loc2c.c
> index a53214f..ead1003 100644
> --- a/gdb/compile/compile-loc2c.c
> +++ b/gdb/compile/compile-loc2c.c
> @@ -722,6 +722,7 @@ do_compile_dwarf_expr_to_c (int indent, string_file
> &stream,
> break;
>
> case DW_OP_addr:
> + uoffset = extract_unsigned_integer (op_ptr, addr_size, byte_order);
> op_ptr += addr_size;
> /* Some versions of GCC emit DW_OP_addr before
> DW_OP_GNU_push_tls_address. In this case the value is an
Hi Tom,
As you are the original author of that code, would it be possible for
you to take a quick look, if you remember any of this :) ?
Thanks,
Simon
next prev parent reply other threads:[~2017-06-25 17:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-10 19:49 Simon Marchi
2017-06-25 17:24 ` Simon Marchi [this message]
2017-07-09 16:44 ` Tom Tromey
2017-07-09 18:28 ` Simon Marchi
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