[Bug debug/42657] New: Missing debug info for a variable

[Bug debug/42657] New: Missing debug info for a variable

[jakub at gcc dot gnu dot org]

At -g -O2 var1 has a location attribute, but var2 does not.

extern unsigned int extfn (char *x);

static inline int
foo (const char *x, int y)
{
  int a = 0;
  a = extfn (y ? __builtin_strdup (x) : (char *) x);
  const char *var1 = x;
  int var2 = a;
  __asm__ volatile ("/* %0 %1 */" : : "r" (var1), "r" (var2));
  return a;
}

int
bar (const char *x)
{
  return foo (x, 1);
}

int
baz (const char *x)
{
  return foo (x, 0);
}

although obviously there is a register in which var2 is present (the one passed
to the inline asm.
The debug stmt is reset during inlining:
./cc1 -O2 -g rh552376.i -fdump-ipa-all -quiet; grep var rh552376.i.04[12]*
rh552376.i.041i.cp:  # DEBUG var1 => x_4(D)
rh552376.i.041i.cp:  # DEBUG var2 => a_9
rh552376.i.042i.inline:  # DEBUG var1 => x_4(D)
rh552376.i.042i.inline:  # DEBUG var2 => a_9
rh552376.i.042i.inline:  # DEBUG var1 => x_4(D)
rh552376.i.042i.inline:  # DEBUG var2 => a_9
rh552376.i.042i.inline:  # DEBUG var1 => x_1(D)
rh552376.i.042i.inline:  # DEBUG var2 => NULL
rh552376.i.042i.inline:  # DEBUG var1 => x_1(D)
rh552376.i.042i.inline:  # DEBUG var2 => NULL


-- 
           Summary: Missing debug info for a variable
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42657

[Bug debug/42657] Missing debug info for a variable

[jakub at gcc dot gnu dot org]

------- Comment #1 from jakub at gcc dot gnu dot org  2010-01-08 10:47 -------
Created an attachment (id=19506)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19506&action=view)
gcc45-pr42657.patch

Inliner fix I'm bootstrapping/regtesting ATM.  Unfortunately this isn't enough
to fix the testcase.
While the debug stmts/insns are preserved until var-tracking - in compgotos we
have:
(debug_insn 13 10 14 2 rh552376.i:7 (var_location:SI a (reg:SI 0 ax [orig:58
D.2702 ] [58])) -1 (nil))

(debug_insn 14 13 15 2 rh552376.i:8 (var_location:DI var1 (reg/v/f:DI 3 bx
[orig:61 x ] [61])) -1 (nil))

(debug_insn 15 14 16 2 rh552376.i:9 (var_location:SI var2 (reg:SI 0 ax [orig:58
D.2702 ] [58])) -1 (nil))

(insn:TI 16 15 27 2 rh552376.i:10 (parallel [
            (asm_operands/v ("/* %0 %1 */") ("") 0 [
                    (reg/v/f:DI 3 bx [orig:61 x ] [61])
                    (reg:SI 0 ax [orig:58 D.2702 ] [58])
                ]
                 [
                    (asm_input:DI ("r") (null):0)
                    (asm_input:SI ("r") (null):0)
                ]
                 [] rh552376.i:24)
            (clobber (reg:QI 18 fpsr))
            (clobber (reg:QI 17 flags))
        ]) -1 (expr_list:REG_DEAD (reg/v/f:DI 3 bx [orig:61 x ] [61])
        (expr_list:REG_UNUSED (reg:QI 18 fpsr)
            (expr_list:REG_UNUSED (reg:QI 17 flags)
                (nil)))))
var-tracking only gives location for x and var1 and not a and var2:
(note/c 44 10 43 2 (var_location x (expr_list:REG_DEP_TRUE (reg/v/f:DI 3 bx
[orig:61 x ] [61])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note/c 43 44 45 2 (var_location x (expr_list:REG_DEP_TRUE (reg/v/f:DI 3 bx
[orig:61 x ] [61])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note 45 43 46 2 (var_location a (expr_list:REG_DEP_TRUE (reg:SI 0 ax [orig:58
D.2702 ] [58])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note 46 45 48 2 (var_location var1 (expr_list:REG_DEP_TRUE (reg/v/f:DI 3 bx
[orig:61 x ] [61])
    (const_int 0 [0x0]))) NOTE_INSN_VAR_LOCATION)

(note 48 46 47 2 (var_location var2 (nil)) NOTE_INSN_VAR_LOCATION)

(note 47 48 16 2 (var_location a (nil)) NOTE_INSN_VAR_LOCATION)

(insn:TI 16 47 27 2 rh552376.i:10 (parallel [
            (asm_operands/v ("/* %0 %1 */") ("") 0 [
                    (reg/v/f:DI 3 bx [orig:61 x ] [61])
                    (reg:SI 0 ax [orig:58 D.2702 ] [58])
                ]
The patch actually makes things worse in this testcase, but only in the
vartrack phase - that's because compared to without the patch var-tracking now
adds both the note 48 and note 47, before that there was neither of these
notes.
Which means that not only it doesn't know where var2 lives (it didn't know it
before either), but doesn't know where a lives either, eventhough the a in %eax
was correct.
So we need to also fix var-tracking...


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42657

[Bug debug/42657] Missing debug info for a variable

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42657

[Bug debug/42657] Missing debug info for a variable

[jakub at gcc dot gnu dot org]

------- Comment #2 from jakub at gcc dot gnu dot org  2010-01-11 12:18 -------
http://gcc.gnu.org/ml/gcc-patches/2010-01/msg00430.html
http://gcc.gnu.org/ml/gcc-patches/2010-01/msg00431.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42657

[Bug debug/42657] Missing debug info for a variable

[jakub at gcc dot gnu dot org]

------- Comment #3 from jakub at gcc dot gnu dot org  2010-01-14 22:39 -------
Subject: Bug 42657

Author: jakub
Date: Thu Jan 14 22:38:29 2010
New Revision: 155917

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=155917
Log:
        PR debug/42657
        * tree-inline.c (copy_debug_stmt): Don't reset debug stmt just
        because its first operand is a non-localized variable.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-inline.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42657

[Bug debug/42657] Missing debug info for a variable

[jakub at gcc dot gnu dot org]

------- Comment #4 from jakub at gcc dot gnu dot org  2010-01-14 23:21 -------
Fixed.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42657