[Bug c++/60948] New: incorrect debug info for reference type of function parameters

[chihin.ko at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60948

            Bug ID: 60948
           Summary: incorrect debug info for reference type of function
                    parameters
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chihin.ko at oracle dot com

cat t.cc

#include <stdio.h>

int f(int &r) {
   r = r + 1;
   return r;
}

main(void) {

    int j = 99;
    int i = 99;

    printf("i = %d\n",i);
    printf("f(i) = %d\n",f(i));
    printf("i = %d\n",i);

    return 0;
} 

(dbx) stop at 11;run
(2) stop at "calls_with_refs.cc":11
Running: a.out
(process id 14632)
stopped in main at line 11 in file "calls_with_refs.cc"
   11       int i = 99;
(dbx) call f(33)  <== should have errmsg "dbx: The ref (&) parameters to `f'
cannot be literals" 
-------------------------------------------------------------------------
this is due to g++ generate wrong debug info
for function f(int &), there is an extra "const" , f(const int &),
if there is no "const", then call "f" with constant e.g. f(33), is illegal,
if there is "const", then "call f(33)" is legal. 
--------------------------------------------------------------------
There is an extra DW_TAG_const_type for parameter "r" of function "f"
< 2><0x00000482>      DW_TAG_formal_parameter
                        DW_AT_name                  "r"
                        DW_AT_decl_line             0x00000003
                        DW_AT_type                  <0x0000048f>
...
...
< 1><0x0000048f>    DW_TAG_const_type   <== should not have this TAG
                      DW_AT_type                  <0x00000494>