This is the mail archive of the gdb-patches@sources.redhat.com mailing list for the GDB project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: RFA: dwarf2read.c patch


J. Johnston writes:
 > The following patch fixes a problem on ia64.  In dwarf2read.c,
 > dwarf_decode_lines(), the function check_cu_functions() is called
 > to check for a specific scenario caused by gcc.
 > 
 > The function takes an address and returns an address.  In some
 > cases, it will return the lowpc value of the function rather than
 > the address that was input.
 > 
 > On the ia64, this causes problems because the line table info spit
 > out by the compiler is often specified with relative addresses.
 > As well, ia64 addresses are special as they encode a slot number which goes
 > 0, 1, 2, then skips to the next quadword boundary.  For example,
 > 
 > 0x00, 0x01, 0x02, 0x10, 0x11, 0x12, 0x20, 0x21, 0x22, ...
 > 
 > Addresses such as 0x0e or 0x0f are invalid and cause an error to
 > occur if, say, a breakpoint was attempted to be inserted there.
 > 
 > Now, in dwarf_decode_lines(), if we update the address counter when we call
 > check_cu_functions(), adding relative offsets in subsequent entries often results in
 > invalid addresses.
 > 
 > This patch makes it so the check_cu_functions() call is only used to
 > alter the address passed to record_line(); the calculated address is left untouched
 > so subsequent relative operations result in valid results.
 > 
 > Tested on ia64 and x86.
 > 
 > Ok to commit?
 > 
 > -- Jeff J.
 > 
 > 2003-05-05  Jeff Johnston  <jjohnstn@redhat.com>
 > 
 > 	* dwarf2read.c (dwarf_decode_lines): Only use output of check_cu_functions()
 > 	when calling record_line().  Do not update the current address.

yes, ok.

elena


 > Index: dwarf2read.c
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/dwarf2read.c,v
 > retrieving revision 1.90
 > diff -u -p -r1.90 dwarf2read.c
 > --- dwarf2read.c	15 Apr 2003 23:07:11 -0000	1.90
 > +++ dwarf2read.c	5 May 2003 21:55:26 -0000
 > @@ -4878,8 +4878,8 @@ dwarf_decode_lines (struct line_header *
 >  		* lh->minimum_instruction_length;
 >  	      line += lh->line_base + (adj_opcode % lh->line_range);
 >  	      /* append row to matrix using current values */
 > -	      address = check_cu_functions (address);
 > -	      record_line (current_subfile, line, address);
 > +	      record_line (current_subfile, line, 
 > +	                   check_cu_functions (address));
 >  	      basic_block = 1;
 >  	    }
 >  	  else switch (op_code)
 > @@ -4925,8 +4925,8 @@ dwarf_decode_lines (struct line_header *
 >  		}
 >  	      break;
 >  	    case DW_LNS_copy:
 > -	      address = check_cu_functions (address);
 > -	      record_line (current_subfile, line, address);
 > +	      record_line (current_subfile, line, 
 > +	                   check_cu_functions (address));
 >  	      basic_block = 0;
 >  	      break;
 >  	    case DW_LNS_advance_pc:


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]