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



> On May 7, 2014, at 2:32 AM, "Herman, Andrei" <Andrei_Herman@codesourcery.com> wrote:
> 
> 
> Hi,
> 
> Currently GCC only emits DWARF debug information (DW_TAG_lexical_block DIEs)
> for compound statements containing significant local declarations.
> However, code coverage tools that process the DWARF debug information to
> implement block/path coverage need more complete lexical block information. 
> 
> This patch adds the necessary functionality under the control of a new 
> command line argument: -fforce-dwarf-lexical-blocks.
> 
> When this flag is set, a DW_TAG_lexical_block DIE will be emitted 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 labeled
> 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. 
> Consequently, any case in a switch statement that does not flow through to 
> the next case, will have its own dwarf lexical block.
> 
> The complete change proposal contains 4 patches (attached first 3):
> 1. Add command line option -fforce-dwarf-lexical-blocks

This option since it is specific to the c frontend should go into c.opt instead of common.opt. Unless you are going to extend this to Ada, Java and fortran. 

Thanks,
Andrew


> 2. Use of flag_force_dwarf_blocks
> 3. Create label scopes
> 
> A forth patch, extending the proposed functionality to C++ will be submitted in a separate message.
> 
> Attached are the proposed ChangeLog additions, named according to the directory each one belongs to.
> 
> Best regards,
> Andrei Herman
> Mentor Graphics Corporation
> Israel branch 
> 
> <gcc_c_ChangeLog>
> <gcc_c-family_ChangeLog>
> <gcc_ChangeLog>
> <0001-Add-command-line-option-fforce_dwarf_lexical_blocks.patch>
> <0002-Use-flag_force_dwarf_blocks.patch>
> <0003-Create-label-scopes.patch>


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