[Bug target/63223] New: [avr] Make jumptables work with -Wl,--section-start,.text=

[Bug target/63223] New: [avr] Make jumptables work with -Wl,--section-start,.text=

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

            Bug ID: 63223
           Summary: [avr] Make jumptables work with
                    -Wl,--section-start,.text=
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gjl at gcc dot gnu.org

avr-gcc assumes that jumptables in section .progmem.gcc_sw_table are located in
the lower 64k of flash and uses LPM to read from these tables.

This does no more hold if the code is shifted to a higher address by, e.g.
-Wl,--section-start,.text=... which is commonly used with bootloadres.

This PR implements ELPM to access jumptables as needed.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Author: gjl
Date: Thu Sep 11 08:08:17 2014
New Revision: 215152

URL: https://gcc.gnu.org/viewcvs?rev=215152&root=gcc&view=rev
Log:
gcc/
    PR target/63223
    * config/avr/avr.md (*tablejump.3byte-pc): New insn.
    (*tablejump): Restrict to !AVR_HAVE_EIJMP_EICALL.  Add void clobber.
    (casesi): Expand to *tablejump.3byte-pc if AVR_HAVE_EIJMP_EICALL.
libgcc/
    PR target/63223
    * config/avr/libgcc.S (__tablejump2__): Rewrite to use RAMPZ, ELPM
    and R24 as needed.  Make work for all devices and .text locations.
    (__do_global_ctors, __do_global_dtors): Use word addresses.
    (__tablejump__, __tablejump_elpm__): Remove functions.
    * t-avr (LIB1ASMFUNCS): Remove _tablejump, _tablejump_elpm.
    Add _tablejump2.
    (XICALL, XIJMP): New macros.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/avr/avr.md
    trunk/libgcc/ChangeLog
    trunk/libgcc/config/avr/lib1funcs.S
    trunk/libgcc/config/avr/t-avr

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #2 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Author: gjl
Date: Thu Sep 11 08:19:45 2014
New Revision: 215153

URL: https://gcc.gnu.org/viewcvs?rev=215153&root=gcc&view=rev
Log:
gcc/
    Backport from 2014-09-11 trunk r215152.
    PR target/63223
    * config/avr/avr.md (*tablejump.3byte-pc): New insn.
    (*tablejump): Restrict to !AVR_HAVE_EIJMP_EICALL.  Add void clobber.
    (casesi): Expand to *tablejump.3byte-pc if AVR_HAVE_EIJMP_EICALL.
libgcc/
    Backport from 2014-09-11 trunk r215152.
    PR target/63223
    * config/avr/libgcc.S (__tablejump2__): Rewrite to use RAMPZ, ELPM
    and R24 as needed.  Make work for all devices and .text locations.
    (__do_global_ctors, __do_global_dtors): Use word addresses.
    (__tablejump__, __tablejump_elpm__): Remove functions.
    * t-avr (LIB1ASMFUNCS): Remove _tablejump, _tablejump_elpm.
    Add _tablejump2.
    (XICALL, XIJMP): New macros.


Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/config/avr/avr.md
    branches/gcc-4_9-branch/libgcc/ChangeLog
    branches/gcc-4_9-branch/libgcc/config/avr/lib1funcs.S
    branches/gcc-4_9-branch/libgcc/config/avr/t-avr

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

Georg-Johann Lay <gjl at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |4.9.2

--- Comment #3 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Fixed in 4.9.2.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[amylaar at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> changed:

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

--- Comment #4 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> ---
(In reply to Georg-Johann Lay from comment #1)
> Author: gjl
> Date: Thu Sep 11 08:08:17 2014
> New Revision: 215152
> 
> URL: https://gcc.gnu.org/viewcvs?rev=215152&root=gcc&view=rev
> Log:
> gcc/
> 	PR target/63223
> 	* config/avr/avr.md (*tablejump.3byte-pc): New insn.
> 	(*tablejump): Restrict to !AVR_HAVE_EIJMP_EICALL.  Add void clobber.
> 	(casesi): Expand to *tablejump.3byte-pc if AVR_HAVE_EIJMP_EICALL.
> libgcc/
> 	PR target/63223
> 	* config/avr/libgcc.S (__tablejump2__): Rewrite to use RAMPZ, ELPM
> 	and R24 as needed.  Make work for all devices and .text locations.
> 	(__do_global_ctors, __do_global_dtors): Use word addresses.

do_global_dtors is supposed to start at the start and increment from there.
I see it used to be half-way wrong and half-way correct.
(Starting at the start, decrementing for __AVR_HAVE_ELPM__, incrementing
otherwise.)
However, you now made it all the way use an incorrect order - starting at the
end and incrementing from there.
Is there a rationale for this?
>From gcc-bugs-return-464361-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Fri Oct 17 14:51:58 2014
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From: "trippels at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/63576] New: [5 Regression] ICE : in ipa_merge_profiles, at ipa-utils.c:540 during Firefox LTO/PGO build
Date: Fri, 17 Oct 2014 14:51:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idc576

            Bug ID: 63576
           Summary: [5 Regression] ICE : in ipa_merge_profiles, at
                    ipa-utils.c:540 during Firefox LTO/PGO build
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: trippels at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org

% wget trippelsdorf.de/testcase.tar.bz2
 % tar xvjf testcase.tar.bz2
 % g++ -w -march=amdfam10 -flto=4 -fprofile-use -fprofile-correction
-ffunction-sections -fdata-sections -fno-rtti -fno-exceptions -fno-math-errno
-std=gnu++0x -pipe -O3 Unified_cpp_js_src1.ii Unified_cpp_js_src2.ii
Unified_cpp_js_src3.ii
lto1: internal compiler error: in ipa_merge_profiles, at ipa-utils.c:540
0x7f7d55 ipa_merge_profiles(cgraph_node*, cgraph_node*)
        ../../gcc/gcc/ipa-utils.c:540
0xf57883 ipa_icf::sem_function::merge(ipa_icf::sem_item*)
        ../../gcc/gcc/ipa-icf.c:625
0xf5cc86 ipa_icf::sem_item_optimizer::merge_classes(unsigned int)
        ../../gcc/gcc/ipa-icf.c:2241
0xf60bf9 ipa_icf::sem_item_optimizer::execute()
        ../../gcc/gcc/ipa-icf.c:1602
0xf61671 ipa_icf_driver
        ../../gcc/gcc/ipa-icf.c:2319
0xf61671 ipa_icf::pass_ipa_icf::execute(function*)
        ../../gcc/gcc/ipa-icf.c:2366
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions

-fno-ipa-icf "fixes" the issue.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[amylaar at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #5 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> ---
I also observe that the cpi/cpc/brne idiom that is used throughout -
before and after your patch - is nonsentical.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[amylaar at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #6 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> ---
(In reply to Jorn Wolfgang Rennecke from comment #4)
> However, you now made it all the way use an incorrect order - starting at the
> end and incrementing from there.
Oops, I mean decrementing from there.  But the point still stands.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[amylaar at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #7 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> ---
(In reply to Jorn Wolfgang Rennecke from comment #5)
> I also observe that the cpi/cpc/brne idiom that is used throughout -
> before and after your patch - is nonsentical.

Oops, I drew conclusions from the "operation" short description of CPC that are
not borne out by the detailed flag setting description.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #8 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
(In reply to Jorn Wolfgang Rennecke from comment #4)
> (In reply to Georg-Johann Lay from comment #1)
> do_global_dtors is supposed to start at the start and increment from there.
> I see it used to be half-way wrong and half-way correct.
> (Starting at the start, decrementing for __AVR_HAVE_ELPM__, incrementing
> otherwise.)
> However, you now made it all the way use an incorrect order - starting at the
> end and incrementing from there.
> Is there a rationale for this?

The old code was broken as it decremented begainning at the start address.  The
flaw never came apparent for __dtors_start = __dtors_end or with simulators
that terminated in exit.

The new code uses the same traverse direction like __do_global_ctors.

Is the order of .ctors, .dtors defined in any way?  I.e. how do you express
that constructor A must run before constructor B in the C program?  Same for
destructors.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[amylaar at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #9 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> ---
(In reply to Georg-Johann Lay from comment #8)
> (In reply to Jorn Wolfgang Rennecke from comment #4)
> > (In reply to Georg-Johann Lay from comment #1)
> > do_global_dtors is supposed to start at the start and increment from there.
> > I see it used to be half-way wrong and half-way correct.
> > (Starting at the start, decrementing for __AVR_HAVE_ELPM__, incrementing
> > otherwise.)
> > However, you now made it all the way use an incorrect order - starting at the
> > end and incrementing from there.
> > Is there a rationale for this?
> 
> The old code was broken as it decremented begainning at the start address. 
> The flaw never came apparent for __dtors_start = __dtors_end or with
> simulators that terminated in exit.
> 
> The new code uses the same traverse direction like __do_global_ctors.
> 
> Is the order of .ctors, .dtors defined in any way?  I.e. how do you express
> that constructor A must run before constructor B in the C program?  Same for
> destructors.

The C++ standard says that destructors have to run in reverse order of
completion
of constructors.
crtstuff.c:__do_global_ctors_aux starts at the first constructor, and
increments from there;
crtstuff.c:__do_global_dtors_aux starts at the last destructor, and decrements
from there.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[amylaar at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #10 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> ---
Created attachment 33768
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33768&action=edit
patch for dtor direction

I have this patch for fixing the direction of the dtor execution,
but I got stuck trying to write a testcase.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #11 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
(In reply to Jorn Wolfgang Rennecke from comment #10)
> Created attachment 33768 [details]
> patch for dtor direction
> 
> I have this patch for fixing the direction of the dtor execution,
> but I got stuck trying to write a testcase.

That won't work.  I'll install a working implementation soon so you can
proceed.

[Bug target/63223] [avr] Make jumptables work with -Wl,--section-start,.text=

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63223

--- Comment #12 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Author: gjl
Date: Wed Oct 22 10:46:11 2014
New Revision: 216551

URL: https://gcc.gnu.org/viewcvs?rev=216551&root=gcc&view=rev
Log:
    PR target/63223
    * config/avr/lib1funcs.S (__do_global_dtors): Reverse execution
    order to first...last.


Modified:
    branches/gcc-4_9-branch/libgcc/ChangeLog
    branches/gcc-4_9-branch/libgcc/config/avr/lib1funcs.S