Re: [PATCH GCC]Add 'force-dwarf-lexical-blocks' command line option

["Herman, Andrei" <Andrei_Herman at codesourcery dot com>]

Please find attached the fixed patch files for this change:
	1. Add command line option -fforce-dwarf-lexical-blocks.
	2. Support flag_force_dwarf_blocks in C.
	3. Support flag_force_dwarf_blocks in C++.

Attached also are the proposed ChangeLog additions, named according to 
the directory each one belongs to.

All check-c and check-c++ tests have been run for unix target, with and 
without the new option.
The only test that failed with the -fforce-dwarf-lexical-blocks set and 
passed without this flag was:
FAIL: gcc.dg/debug/dwarf2/inline2.c scan-assembler-times \\(DIE 
\\([^\n]*\\) DW_TAG_lexical_block 6
as expected.

Best regards,
Andrei Herman
Mentor Graphics Corporation
Israel branch


On 6/20/2014 12:09 AM, Joseph S. Myers wrote:
> On Sun, 1 Jun 2014, Herman, Andrei wrote:
>
> > +  /* The -fforce-dwarf-lexical-blocks option is only relevant when debug
> > +     info is in DWARF4 format */
> > +  if (flag_force_dwarf_blocks) {
>
> Watch coding style: the opening '{' always goes on the next line.
>
> > +fforce-dwarf-lexical-blocks
> > +C C++ Var(flag_force_dwarf_blocks)
> > +Force generation of lexical blocks in dwarf output
>
> I don't see a good reason for this not to be supported for ObjC and ObjC++
> as well.  Say DWARF, not dwarf.
>
> > +@item -fforce-dwarf-lexical-blocks
> > +Produce debug information (a DW_TAG_lexical_block) for every function
> > +body, loop body, switch body, case statement, if-then and if-else statement,
> > +even if the body is a single statement.  Likewise, a lexical block will be
> > +emitted for the first label of a statement.  This block ends at the end of the
> > +current lexical scope, or when a break, continue, goto or return statement is
> > +encountered at the same lexical scope level.  This option is usefull for
> > +coverage tools that utilize the dwarf debug information.
> > +This option only applies to C/C++ code and is available when using DWARF
> > +Version 4 or higher.
>
> Use @code{} markup for keywords (if, else, break, continue, goto, return).
> "useful" not "usefull".  "DWARF" not "dwarf".
>
> > +/* Create a block_loc struct for a statement list created on behalf of
> > +   flag_force_dwarf_blocks.  We use this for label or forced c99 scopes.  */
> > +
> > +void
> > +push_block_info (tree block, location_t loc, bool is_label)
> > +{
> > +  if (TREE_CODE(block) != STATEMENT_LIST)
>
> Watch coding style: space before '(' in function and macro calls (and
> similar calls such as sizeof) (many places in this patch, not just this
> one).
>
> > +tree
> > +pop_block_info (location_t &loc)
>
> It's not documented in codingconventions.html, but I think it's preferred
> to avoid returning values through reference arguments (see e.g.
> <https://gcc.gnu.org/ml/gcc-patches/2013-11/msg00198.html>).
>
> > +{
> > +  block_loc  tl = NULL;
>
> Excess space between "block_loc" and "tl".
>
> > @@ -4679,7 +4712,7 @@ c_parser_compound_statement_nostart (c_parser *parser)
> >     expressions being rejected later.  */
> >
> > static void
> > -c_parser_label (c_parser *parser)
> > +c_parser_label (c_parser *parser, bool prev_label)
>
> You're adding a new argument - you need to update the comment above this
> function to explain the semantics of this argument.
>
> In general, make sure that new functions have comments above them that
> explain the semantics of the arguments (by name) and any return value.
>
> > +/* If current scope is a label scope, pop it from block info stack
> > +   and close it's compound statement.  */
>
> "its" not "it's".

Attachment: 0001-Add-command-line-option-fforce-dwarf-lexical-blocks.patch
Description: Text document

Attachment: 0002-Support-flag_force_dwarf_blocks-in-C.patch
Description: Text document

Attachment: 0003-Support-flag_force_dwarf_blocks-in-Cplusplus.patch
Description: Text document

Attachment: gcc_c_ChangeLog
Description: Text document

Attachment: gcc_c-family_ChangeLog
Description: Text document

Attachment: gcc_ChangeLog
Description: Text document

Attachment: gcc_cp_ChangeLog
Description: Text document