[Bug target/18434] [4.0/4.1 Regression] Cannot build gnattools on Tru64 UNIX V5.1B

[ro at techfak dot uni-bielefeld dot de]

------- Additional Comments From ro at techfak dot uni-bielefeld dot de  2005-07-05 17:04 -------
Subject: Re:  [4.0/4.1 Regression] Cannot build gnattools on Tru64 UNIX V5.1B

charlet at gcc dot gnu dot org writes:

> Given your last comment (a variable set to 4), it still looks very much like
> a codegen issue to me, and likely target dependent.
> 
> I guess a next step could be to either look at the ssa transformations performed,
> and/or at the assembly code generated for the elab routine.

I've approached this a bit differently:

* I tried to bootstrap mainline with -O0, but it failed as before and even
  an almost current CVS gdb just SEGVs on the gnatmake binary ;-(

* On the 4.0 branch, a bootstrap with -O0 also failed as before, but at
  least I can debug the gnatmake binary:

  osint__running_programs starts as 0, is later initialized to 2
  (osint__make) in osint__set_program and again overwritten to 4
  (osint__unspecified) in osint___elabb:

Breakpoint 4, osint.set_program (p=16) at /vol/gnu/src/gcc/gcc-4.0-branch-dist/gcc/ada/osint.adb:2274
(gdb) p osint__running_program
$6 = 0
(gdb) where
#0  osint.set_program (p=16) at /vol/gnu/src/gcc/gcc-4.0-branch-dist/gcc/ada/osint.adb:2274
#1  0x00000001201fbf10 in <osint__m___elabb> () at /vol/gnu/src/gcc/gcc-4.0-branch-dist/gcc/ada/osint-m.adb:49
#2  0x00000001200b7750 in adainit () at b_gnatm.c:562
#3  0x00000001200b8aec in main (argc=536854608, argv=0x0, envp=0x0) at b_gnatm.c:733
#4  0x00000001200b617c in __start ()
(gdb) cont
Continuing.
Watchpoint 6: {<data variable, no debug info>} 5369590752

Old value = 0
New value = 2
osint.set_program (p=16) at /vol/gnu/src/gcc/gcc-4.0-branch-dist/gcc/ada/osint.adb:2280
(gdb) cont
Continuing.

Breakpoint 3, <osint___elabb> () at /vol/gnu/src/gcc/gcc-4.0-branch-dist/gcc/ada/osint.adb:45
(gdb) cont
Continuing.
Watchpoint 6: {<data variable, no debug info>} 5369590752

Old value = 2
New value = 4
<osint___elabb> () at /vol/gnu/src/gcc/gcc-4.0-branch-dist/gcc/ada/osint.adb:48
(gdb) where
#0  <osint___elabb> () at /vol/gnu/src/gcc/gcc-4.0-branch-dist/gcc/ada/osint.adb:48
#1  0x00000001200b7cc0 in adainit () at b_gnatm.c:610
#2  0x00000001200b8aec in main (argc=536854608, argv=0x0, envp=0x0) at b_gnatm.c:733
#3  0x00000001200b617c in __start ()

* On the 3.4 branch, osint__running_program is statically initialized to
  osint__unspecified in osint.adb, later reset to osint__make in
  osint__set_program:

Old value = {F = osint__unspecified}
New value = {F = osint__make}
osint__set_program (p=osint__make) at /vol/gnu/src/gcc/gcc-3.4-branch-dist/gcc/ada/osint.adb:2253

Breakpoint 3, osint.set_program (p=osint__make) at /vol/gnu/src/gcc/gcc-3.4-branch-dist/gcc/ada/osint.adb:2247
(gdb) where
#0  osint.set_program (p=osint__make) at /vol/gnu/src/gcc/gcc-3.4-branch-dist/gcc/ada/osint.adb:2247
#1  0x000000012019efe8 in <osint__m___elabb> () at /vol/gnu/src/gcc/gcc-3.4-branch-dist/gcc/ada/osint-m.adb:49
#2  0x00000001200a046c in adainit () at b_gnatm.c:267
#3  0x00000001200a11c0 in main (argc=6, argv=0x11fffc018, envp=0x11fffc050) at b_gnatm.c:389
#4  0x000000012009fc3c in __start ()
$1 = {F = osint__unspecified}
(gdb) cont
Continuing.
Watchpoint 5: osint.running_program

Old value = {F = osint__unspecified}
New value = {F = osint__make}
osint.set_program (p=osint__make) at /vol/gnu/src/gcc/gcc-3.4-branch-dist/gcc/ada/osint.adb:2253

Thus, the way/order of initialization changed between 3.4 and 4.0, causing
the observed failure:

* from osint.adb:

package body Osint is

   Running_Program : Program_Type := Unspecified;
   --  comment required here ???

* from osint-m.adb:

package body Osint.M is
[...]
begin
   Set_Program (Make);
end Osint.M;

* in 3.4:

  osint__running_program = osint__unspecified (4) statically (osint.o)

  osint__running_program = osint__make (2) in osint.set_program, called
  from osint__m___elabb (osint_m.o)

* in 4.0:

  osint__running_program = 0 statically (osint.o)

  osint__running_program = osint__make (2) in osint.set_program, called from
  osint__m___elabb (osint_m.o)

  osint__running_program = osint__unspecified (4) in osint___elabb (osint.o)

Hope this helps to narrow down the root cause.

	Rainer



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18434