Re: [PATCH] gdb: reject inserting breakpoints between functions

[Lancelot SIX <lsix@lancelotsix.com>]

Hi,

I have just sent a patch[1] which sits on top of this one.  I do not think
there have been feedbacks on this yet, so I'd like to ping on this one on
behalf on Simon.

For what it is worth, I do agree with the change proposed changes as
it is a pre-requisite for what I am proposing in [1].

Thanks,
Lancelot.

[1] https://sourceware.org/pipermail/gdb-patches/2022-June/190150.html


> diff --git a/gdb/linespec.c b/gdb/linespec.c
> index 9d4707cbb4e7..dd31cf2a9fc4 100644
> --- a/gdb/linespec.c
> +++ b/gdb/linespec.c
> @@ -2133,11 +2140,44 @@ create_sals_line_offset (struct linespec_state *self,
>  	    struct symbol *sym = (blocks[i]
>  				  ? block_containing_function (blocks[i])
>  				  : NULL);
> +	    symtab_and_line *sal = &intermediate_results[i];
> +
> +	    /* Don't consider a match if:
> +
> +	        - the provided line did not give an exact match (so we started
> +	          looking for lines below until we found one with code
> +	          associated to it)
> +	        - the found location is exactly the start of a function
> +	        - the provided line is above the declaration line of the function
> +
> +	       Consider the following source:
> +
> +	       10 } // end of a previous function
> +	       11
> +	       12 int
> +	       13 main (void)
> +	       14 {
> +	       15   int i = 1;
> +	       16
> +	       17   return 0;
> +	       18 }
> +
> +	       The intent of this heuristic is that a breakpoint requested on
> +	       line 11 and 12 will not result on a breakpoint on main, but a
> +	       breakpoint on line 13 will.  A breakpoint requested on the empty
> +	       line 16 will also result in a breakpoint in main, at line 17.  */
> +	    if (!was_exact
> +		&& sym != nullptr
> +		&& sym->aclass () == LOC_BLOCK
> +		&& sal->pc == BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (sym))

The BLOCK_ENTRY_PC and SYMBOL_BLOCK_VALUE macros have been removed.
This should now be:

+		&& sal->pc == sym->value_block ()->entry_pc ()

> +		&& val.line < sym->line ())
> +	      continue;
>  
>  	    if (self->funfirstline)
> -	      skip_prologue_sal (&intermediate_results[i]);
> -	    intermediate_results[i].symbol = sym;
> -	    add_sal_to_sals (self, &values, &intermediate_results[i],
> +	      skip_prologue_sal (sal);
> +
> +	    sal->symbol = sym;
> +	    add_sal_to_sals (self, &values, sal,
>  			     sym ? sym->natural_name () : NULL, 0);
>  	  }
>      }