[Bug debug/45882] New: No debug info for vars depending on unused parameter

[Bug debug/45882] New: No debug info for vars depending on unused parameter

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45882

           Summary: No debug info for vars depending on unused parameter
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jakub@gcc.gnu.org
                CC: aoliva@gcc.gnu.org


On the attached testcase, b, c, d and e vars unnecessarily don't have any
DW_AT_location information in the debug info.

[Bug debug/45882] No debug info for vars depending on unused parameter

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45882

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-16 08:35:41 UTC ---
Author: jakub
Date: Wed Mar 16 08:35:31 2011
New Revision: 171035

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=171035
Log:
    PR debug/45882
    * rtl.def (ENTRY_VALUE): Change format from "e" to "0".
    * rtl.h (ENTRY_VALUE_EXP): Define.
    * rtl.c (rtx_equal_p_cb, rtx_equal_p): Handle ENTRY_VALUE.
    * cselib.c (rtx_equal_for_cselib_p, cselib_hash_rtx): Likewise.
    * print-rtl.c (print_rtx): Likewise.
    * gengtype.c (adjust_field_rtx_def): Likewise.
    * var-tracking.c (vt_add_function_parameter): Adjust
    gen_rtx_ENTRY_VALUE uses, use ENTRY_VALUE_EXP macro.
    * dwarf2out.c (mem_loc_descriptor): Use ENTRY_VALUE_EXP macro.
    * cfgexpand.c (expand_debug_expr): If a SSA_NAME without
    partition is a default definition of a PARM_DECL, use ENTRY_VALUE
    of its DECL_INCOMING_RTL if possible, or its DECL_RTL if set.

    * gcc.dg/guality/pr45882.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/guality/pr45882.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgexpand.c
    trunk/gcc/cselib.c
    trunk/gcc/dwarf2out.c
    trunk/gcc/gengtype.c
    trunk/gcc/print-rtl.c
    trunk/gcc/rtl.c
    trunk/gcc/rtl.def
    trunk/gcc/rtl.h
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/var-tracking.c

[Bug debug/45882] No debug info for vars depending on unused parameter

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45882

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-08 20:43:54 UTC ---
Fixed for 4.7+.

[Bug debug/45882] No debug info for vars depending on unused parameter

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45882

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |steven at gcc dot gnu.org

--- Comment #4 from Steven Bosscher <steven at gcc dot gnu.org> 2013-04-01 16:39:05 UTC ---
Jakub, do you remember what this change was necessary for:

    * rtl.def (ENTRY_VALUE): Change format from "e" to "0".

I'm reviewing the "0" fields and I don't understand why ENTRY_VALUE
has this "0" instead of "e".

Hope you remember :-)

[Bug debug/45882] No debug info for vars depending on unused parameter

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45882

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-01 18:11:07 UTC ---
ENTRY_VALUE's operand is 0, because in most cases you don't want to let the
various RTL passes to see through the ENTRY_VALUE rtl, they should treat the
RTL as a black box, mostly when you want to look at the operand is either for
rtx_equal_p and similar functions, or when creating those or when the debug
info is emitted from it.  If ENTRY_VALUE's operand is e rather than 0, e.g.
various RTL passes would consider the there referenced hard register (or
memory) to be live at that point, or used, etc., but it actually isn't used.