multiple location in C++ constructors

Denis PILAT denis.pilat@st.com
Tue Oct 14 15:13:00 GMT 2008


We (at ST) have a compiler that generates DW_AT_MIPS_linkage_name 
attributes for constructors.
Unfortunately, that prevents breakpoint in constructor to have multiple 
locations since the gdb heuristics eliminates one location in the 
expand_line_sal_maybe() function of breakpoint.c: see bellow, we go thru 
the remove_sal () line.

(from breakpoint.c)
struct symtabs_and_lines
expand_line_sal_maybe (struct symtab_and_line sal)
...
	  if (find_pc_partial_function (pc, &this_function, 
					&func_addr, &func_end))
	    {
	      if (this_function && 
		  strcmp (this_function, original_function) != 0)
		{
		  remove_sal (&expanded, i);
		  --i;
		}
	      else if (func_addr == pc)	    
...



If present into dwarf2 debug information, the find_pc_partial_function() 
returns the DW_AT_MIPS_linkage_name in this_function, which is alway 
different from the original_function. Therefore there is always only one 
location for constructor breakpoints since the DW_AT_MIPS_linkage_name 
is filled with the mangled function name.


My question is:
Is the GDB heuristic to find multiple location for breakpoint wrong ?
Or is the DW_AT_MIPS_linkage_name attribute for constructors useless in 
debug informations ?

Thanks for your feedback
Denis



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