[PATCH 1/2] gdb/dwarf: remove line_header::total_length field

[PATCH 1/2] gdb/dwarf: remove line_header::total_length field

[Simon Marchi]

This doesn't have to be a field, it can simply be a local variable in
dwarf_decode_line_header.  Name the local variable "unit_length", since
that's what the field in called in DWARF 4 and 5.  It's always easier to
follow the code with the standard on the side when we use the same
terminology.

Change-Id: I3ad1022afd9410b193ea11b9b5437686c1e4e633
---
 gdb/dwarf2/line-header.c | 6 +++---
 gdb/dwarf2/line-header.h | 1 -
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/gdb/dwarf2/line-header.c b/gdb/dwarf2/line-header.c
index 8f4eb4f124cf..b1dd9afc5f58 100644
--- a/gdb/dwarf2/line-header.c
+++ b/gdb/dwarf2/line-header.c
@@ -289,19 +289,19 @@ dwarf_decode_line_header  (sect_offset sect_off, bool is_dwz,
   line_ptr = section->buffer + to_underlying (sect_off);
 
   /* Read in the header.  */
-  lh->total_length =
+  LONGEST unit_length =
     read_checked_initial_length_and_offset (abfd, line_ptr, cu_header,
 					    &bytes_read, &offset_size);
   line_ptr += bytes_read;
 
   const gdb_byte *start_here = line_ptr;
 
-  if (line_ptr + lh->total_length > (section->buffer + section->size))
+  if (line_ptr + unit_length > (section->buffer + section->size))
     {
       dwarf2_statement_list_fits_in_line_number_section_complaint ();
       return 0;
     }
-  lh->statement_program_end = start_here + lh->total_length;
+  lh->statement_program_end = start_here + unit_length;
   lh->version = read_2_bytes (abfd, line_ptr);
   line_ptr += 2;
   if (lh->version > 5)
diff --git a/gdb/dwarf2/line-header.h b/gdb/dwarf2/line-header.h
index 4adfe91b8ac4..25b9e7c20327 100644
--- a/gdb/dwarf2/line-header.h
+++ b/gdb/dwarf2/line-header.h
@@ -136,7 +136,6 @@ struct line_header
   /* OFFSET is for struct dwz_file associated with dwarf2_per_objfile.  */
   unsigned offset_in_dwz : 1; /* Can't initialize bitfields in-class.  */
 
-  unsigned int total_length {};
   unsigned short version {};
   unsigned int header_length {};
   unsigned char minimum_instruction_length {};
-- 
2.26.2

[PATCH 2/2] gdb/dwarf: remove line_header::header_length field

[Simon Marchi]

This can be a local in dwarf_decode_line_header.

Change-Id: I2ecf4616d1a3197bd1e81ded9f999a2da9a685af
---
 gdb/dwarf2/line-header.c | 6 ++++--
 gdb/dwarf2/line-header.h | 1 -
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/gdb/dwarf2/line-header.c b/gdb/dwarf2/line-header.c
index b1dd9afc5f58..505fd22cd7d9 100644
--- a/gdb/dwarf2/line-header.c
+++ b/gdb/dwarf2/line-header.c
@@ -329,11 +329,13 @@ dwarf_decode_line_header  (sect_offset sect_off, bool is_dwz,
 	  return NULL;
 	}
     }
-  lh->header_length = read_offset (abfd, line_ptr, offset_size);
+
+  LONGEST header_length = read_offset (abfd, line_ptr, offset_size);
   line_ptr += offset_size;
-  lh->statement_program_start = line_ptr + lh->header_length;
+  lh->statement_program_start = line_ptr + header_length;
   lh->minimum_instruction_length = read_1_byte (abfd, line_ptr);
   line_ptr += 1;
+
   if (lh->version >= 4)
     {
       lh->maximum_ops_per_instruction = read_1_byte (abfd, line_ptr);
diff --git a/gdb/dwarf2/line-header.h b/gdb/dwarf2/line-header.h
index 25b9e7c20327..59b317d0d727 100644
--- a/gdb/dwarf2/line-header.h
+++ b/gdb/dwarf2/line-header.h
@@ -137,7 +137,6 @@ struct line_header
   unsigned offset_in_dwz : 1; /* Can't initialize bitfields in-class.  */
 
   unsigned short version {};
-  unsigned int header_length {};
   unsigned char minimum_instruction_length {};
   unsigned char maximum_ops_per_instruction {};
   unsigned char default_is_stmt {};
-- 
2.26.2

Re: [PATCH 1/2] gdb/dwarf: remove line_header::total_length field

[Lancelot SIX]

>    /* Read in the header.  */
> -  lh->total_length =
> +  LONGEST unit_length =
>      read_checked_initial_length_and_offset (abfd, line_ptr, cu_header,
>  					    &bytes_read, &offset_size);

Hi,

Just a styling nit, the line break should be before the "=".

Best,
Lancelot.

Re: [PATCH 1/2] gdb/dwarf: remove line_header::total_length field

[Simon Marchi]

On 2022-04-21 12:46, Lancelot SIX via Gdb-patches wrote:
>>    /* Read in the header.  */
>> -  lh->total_length =
>> +  LONGEST unit_length =
>>      read_checked_initial_length_and_offset (abfd, line_ptr, cu_header,
>>  					    &bytes_read, &offset_size);
> 
> Hi,
> 
> Just a styling nit, the line break should be before the "=".
> 
> Best,
> Lancelot.


Thanks, fixed locally.

Simon

Re: [PATCH 1/2] gdb/dwarf: remove line_header::total_length field

[Tom Tromey]

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon> This doesn't have to be a field, it can simply be a local variable in
Simon> dwarf_decode_line_header.  Name the local variable "unit_length", since
Simon> that's what the field in called in DWARF 4 and 5.  It's always easier to
Simon> follow the code with the standard on the side when we use the same
Simon> terminology.

Seems fine to me.  Thanks.

Tom

Re: [PATCH 2/2] gdb/dwarf: remove line_header::header_length field

[Tom Tromey]

>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:

Simon> This can be a local in dwarf_decode_line_header.

Looks reasonable.

Tom

Re: [PATCH 2/2] gdb/dwarf: remove line_header::header_length field

[Simon Marchi]

On 2022-04-21 14:43, Tom Tromey wrote:
>>>>>> "Simon" == Simon Marchi via Gdb-patches <gdb-patches@sourceware.org> writes:
> 
> Simon> This can be a local in dwarf_decode_line_header.
> 
> Looks reasonable.
> 
> Tom


Thanks, pushed both patches.

Simon