Fix gdb.dwarf2/dwz.exp for thumb mode

  Yao Qi <yao@codesourcery.com> writes:

> -if { $main_length == "" } {
> +set main_label_offset ""
> +set test "p main_label"
> +gdb_test_multiple $test $test {
> +    -re ".* = {.*} $hex <main\\+($decimal)>.*\r\n$gdb_prompt $" {
> +	set main_label_offset $expect_out(1,string)
> +    }
> +}

Here is the V3 of this patch, to address Andreas's comments about
getting the offset of main_label to main.
  

On 09/15/2014 08:25 PM, Yao Qi wrote:
> Subject: [PATCH] Fix gdb.dwarf2/dwz.exp for thumb mode
> 
> We see the fail in gdb.dwarf2/dwz.exp in thumb mode,
> 
> p the_int^M
> $2 = 99^M
> (gdb) FAIL: gdb.dwarf2/dwz.exp: p the_int
> 
> In thumb mode, the lsb of references to 'main' in the assembly
> (produced by dwarf assember) is set, so the generated debug
> information is incorrect.
> 
> in this patch, we add a label main_label inside function main.  Linker
> doesn't set its lsb in thumb mode, and we can get function main's
> address by 'main_label - $main_label_offset'.  This label isn't moved
> out of function main in both gcc and clang.
> 
> gdb/testsuite:
> 
> 2014-09-15  Yao Qi  <yao@codesourcery.com>
> 
> 	* gdb.dwarf2/main.c (main): New lable main_label.
> 	* gdb.dwarf2/dwz.exp: Get the offset of main_label to main.
> 	Return early if $main_label_offset is unknown.  Get address
> 	of main by "main_label - $main_label_offset".

Ping.  https://sourceware.org/ml/gdb-patches/2014-09/msg00497.html
  

On 09/22/2014 09:47 PM, Yao Qi wrote:
> On 09/15/2014 08:25 PM, Yao Qi wrote:
>> Subject: [PATCH] Fix gdb.dwarf2/dwz.exp for thumb mode
>>
>> We see the fail in gdb.dwarf2/dwz.exp in thumb mode,
>>
>> p the_int^M
>> $2 = 99^M
>> (gdb) FAIL: gdb.dwarf2/dwz.exp: p the_int
>>
>> In thumb mode, the lsb of references to 'main' in the assembly
>> (produced by dwarf assember) is set, so the generated debug
>> information is incorrect.
>>
>> in this patch, we add a label main_label inside function main.  Linker
>> doesn't set its lsb in thumb mode, and we can get function main's
>> address by 'main_label - $main_label_offset'.  This label isn't moved
>> out of function main in both gcc and clang.
>>
>> gdb/testsuite:
>>
>> 2014-09-15  Yao Qi  <yao@codesourcery.com>
>>
>> 	* gdb.dwarf2/main.c (main): New lable main_label.
>> 	* gdb.dwarf2/dwz.exp: Get the offset of main_label to main.
>> 	Return early if $main_label_offset is unknown.  Get address
>> 	of main by "main_label - $main_label_offset".
> 
> Ping.  https://sourceware.org/ml/gdb-patches/2014-09/msg00497.html
> 

Ping.
  

Yao Qi <yao@codesourcery.com> writes:

> On 09/22/2014 09:47 PM, Yao Qi wrote:
>> On 09/15/2014 08:25 PM, Yao Qi wrote:
>>> Subject: [PATCH] Fix gdb.dwarf2/dwz.exp for thumb mode
>>>
>>> We see the fail in gdb.dwarf2/dwz.exp in thumb mode,
>>>
>>> p the_int^M
>>> $2 = 99^M
>>> (gdb) FAIL: gdb.dwarf2/dwz.exp: p the_int
>>>
>>> In thumb mode, the lsb of references to 'main' in the assembly
>>> (produced by dwarf assember) is set, so the generated debug
>>> information is incorrect.
>>>
>>> in this patch, we add a label main_label inside function main.  Linker
>>> doesn't set its lsb in thumb mode, and we can get function main's
>>> address by 'main_label - $main_label_offset'.  This label isn't moved
>>> out of function main in both gcc and clang.
>>>
>>> gdb/testsuite:
>>>
>>> 2014-09-15  Yao Qi  <yao@codesourcery.com>
>>>
>>> 	* gdb.dwarf2/main.c (main): New lable main_label.
>>> 	* gdb.dwarf2/dwz.exp: Get the offset of main_label to main.
>>> 	Return early if $main_label_offset is unknown.  Get address
>>> 	of main by "main_label - $main_label_offset".
>> 
>> Ping.  https://sourceware.org/ml/gdb-patches/2014-09/msg00497.html
>> 
>
> Ping.

Ping.
  

On Mon, Sep 15, 2014 at 8:25 AM, Yao Qi <yao@codesourcery.com> wrote:
> Yao Qi <yao@codesourcery.com> writes:
>
>> -if { $main_length == "" } {
>> +set main_label_offset ""
>> +set test "p main_label"
>> +gdb_test_multiple $test $test {
>> +    -re ".* = {.*} $hex <main\\+($decimal)>.*\r\n$gdb_prompt $" {
>> +     set main_label_offset $expect_out(1,string)
>> +    }
>> +}
>
> Here is the V3 of this patch, to address Andreas's comments about
> getting the offset of main_label to main.
>
> --
> Yao (齐尧)
> From: Yao Qi <yao@codesourcery.com>
> Date: Sat, 13 Sep 2014 14:51:04 +0800
> Subject: [PATCH] Fix gdb.dwarf2/dwz.exp for thumb mode
>
> We see the fail in gdb.dwarf2/dwz.exp in thumb mode,
>
> p the_int^M
> $2 = 99^M
> (gdb) FAIL: gdb.dwarf2/dwz.exp: p the_int
>
> In thumb mode, the lsb of references to 'main' in the assembly
> (produced by dwarf assember) is set, so the generated debug
> information is incorrect.
>
> in this patch, we add a label main_label inside function main.  Linker
> doesn't set its lsb in thumb mode, and we can get function main's
> address by 'main_label - $main_label_offset'.  This label isn't moved
> out of function main in both gcc and clang.
>
> gdb/testsuite:
>
> 2014-09-15  Yao Qi  <yao@codesourcery.com>
>
>         * gdb.dwarf2/main.c (main): New lable main_label.

Typo: label

>         * gdb.dwarf2/dwz.exp: Get the offset of main_label to main.
>         Return early if $main_label_offset is unknown.  Get address
>         of main by "main_label - $main_label_offset".
>
> diff --git a/gdb/testsuite/gdb.dwarf2/dwz.exp b/gdb/testsuite/gdb.dwarf2/dwz.exp
> index 9175f9e..3cf4e4f 100644
> --- a/gdb/testsuite/gdb.dwarf2/dwz.exp
> +++ b/gdb/testsuite/gdb.dwarf2/dwz.exp
> @@ -27,8 +27,9 @@ if  {[gdb_compile ${srcdir}/${subdir}/${srcfile} ${binfile}1.o \
>      return -1
>  }
>
> -# Start GDB and load object file, compute the function length which is
> -# needed in the Dwarf Assembler below.
> +# Start GDB and load object file, compute the function length and the
> +# offset from main to main_label which are needed in the Dwarf Assembler
> +# below.
>  clean_restart ${testfile}1.o
>
>  set main_length ""
> @@ -59,9 +60,17 @@ gdb_test_multiple $test $test {
>      }
>  }
>
> -if { $main_length == "" } {
> +set main_label_offset ""
> +set test "p main_label - main"
> +gdb_test_multiple $test $test {
> +    -re ".* = ($decimal)\r\n$gdb_prompt $" {
> +       set main_label_offset $expect_out(1,string)
> +    }
> +}
> +
> +if { $main_length == "" || $main_label_offset == "" } {
>      # Bail out here, because we can't do the following tests if
> -    # $main_length is unknown.
> +    # $main_length or $main_label_offset is unknown.
>      return -1
>  }
>
> @@ -71,7 +80,7 @@ gdb_exit
>  set asm_file [standard_output_file $srcfile2]
>  Dwarf::assemble $asm_file {
>      declare_labels partial_label int_label int_label2
> -    global main_length
> +    global main_length main_label_offset
>
>      extern main
>
> @@ -79,8 +88,8 @@ Dwarf::assemble $asm_file {
>         partial_label: partial_unit {} {
>             subprogram {
>                 {name main}
> -               {low_pc main addr}
> -               {high_pc "main + $main_length" addr}
> +               {low_pc "main_label - $main_label_offset" addr}
> +               {high_pc "main_label - $main_label_offset + $main_length" addr}
>             }
>         }
>      }
> diff --git a/gdb/testsuite/gdb.dwarf2/main.c b/gdb/testsuite/gdb.dwarf2/main.c
> index 3ddd194..e6d4715 100644
> --- a/gdb/testsuite/gdb.dwarf2/main.c
> +++ b/gdb/testsuite/gdb.dwarf2/main.c
> @@ -20,5 +20,6 @@
>  int
>  main()
>  {
> +  asm ("main_label: .globl main_label");
>    return 0;
>  }

Hi.
I'd like to see comments in the code explaining why main_label exists
(thumb) and why we can't put labels outside the function (clang).

I shouldn't have to grind through commit logs or emails to answer
these questions.