| Message ID | CABu31nP=10OdiCX=dOKb1DWu=ksBYQ2TPb-eSCVgUsbqWSu=Tg@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
> The rl78 apparently doesn't know what it wants to do: > > /* NOTE: defined but zero means dwarf2 debugging, but sjlj EH. */ > #define DWARF2_UNWIND_INFO 0 > /*#define DONT_USE_BUILTIN_SETJMP 1*/ > #undef DONT_USE_BUILTIN_SETJMP > #define JMP_BUF_SIZE (8*3+8) > > But I'll leave that to an rl78 maintainer. RL78 has a return address size different than pointer size, so the default GCC code won't work for EH. For similar reasons, GCC's internal setjmp won't work either.
> The PA and SPARC back ends do not define DONT_USE_BUILTIN_SETJMP, so > they also do not have to define JMP_BUF_SIZE. So: > > * config/sparc/sparc.h (JMP_BUF_SIZE): Do not define. > * config/pa/pa.h (JMP_BUF_SIZE): Likewise. > > OK for trunk? OK for the SPARC, thanks. What about the Stormy16 and the picoChip? It seems like a cleanup is possible in this area for them as well.
On Mon, Jun 25, 2012 at 12:31 AM, DJ Delorie <dj@redhat.com> wrote: > >> The rl78 apparently doesn't know what it wants to do: >> >> /* NOTE: defined but zero means dwarf2 debugging, but sjlj EH. */ >> #define DWARF2_UNWIND_INFO 0 >> /*#define DONT_USE_BUILTIN_SETJMP 1*/ >> #undef DONT_USE_BUILTIN_SETJMP >> #define JMP_BUF_SIZE (8*3+8) >> >> But I'll leave that to an rl78 maintainer. > > RL78 has a return address size different than pointer size, so the > default GCC code won't work for EH. For similar reasons, GCC's > internal setjmp won't work either. Right. And rl78 does *not* define DONT_USE_BUILTIN_SETJMP. In other words, your port *does* use the internal setjmp code right now. If that doesn't work for EH, your port has a bug. Ciao! Steven
On Mon, Jun 25, 2012 at 9:13 AM, Eric Botcazou <ebotcazou@libertysurf.fr> wrote: >> The PA and SPARC back ends do not define DONT_USE_BUILTIN_SETJMP, so >> they also do not have to define JMP_BUF_SIZE. So: >> >> * config/sparc/sparc.h (JMP_BUF_SIZE): Do not define. >> * config/pa/pa.h (JMP_BUF_SIZE): Likewise. >> >> OK for trunk? > > OK for the SPARC, thanks. And thanks to you for the ack! :-) > What about the Stormy16 and the picoChip? It seems > like a cleanup is possible in this area for them as well. Right, I didn't look at the details of the uses of DONT_USE_BUILTIN_SETJMP and JMP_BUF_SIZE but it looks like the ones in picochip and stormy16 are redundant too: For picochip, this port defines DONT_USE_BUILTIN_SETJMP but in the .c file (and after all #includes), so it is never exported and not otherwise referenced in picochip.c, hence dead: config/picochip/picochip.c:#undef DONT_USE_BUILTIN_SETJMP config/picochip/picochip.c:#define DONT_USE_BUILTIN_SETJMP 1 stormy16 only undefines DONT_USE_BUILTIN_SETJMP (which is the default anyway) so these two lines are redundant: config/stormy16/stormy16.h:#undef DONT_USE_BUILTIN_SETJMP config/stormy16/stormy16.h:#define JMP_BUF_SIZE 8 I will remove those lines with the same commit. That leaves only rl78 and ia64: $ egrep "DONT_USE_BUILTIN_SETJMP|JMP_BUF_SIZE" config/* config/*/* config/ia64/freebsd.h:#define JMP_BUF_SIZE 76 config/ia64/hpux.h:#define JMP_BUF_SIZE (8 * 76) config/ia64/ia64.h:#define DONT_USE_BUILTIN_SETJMP config/ia64/linux.h:#define JMP_BUF_SIZE 76 config/ia64/vms.h:#define JMP_BUF_SIZE (8 * 76) config/rl78/rl78.h:/*#define DONT_USE_BUILTIN_SETJMP 1*/ config/rl78/rl78.h:#undef DONT_USE_BUILTIN_SETJMP config/rl78/rl78.h:#define JMP_BUF_SIZE (8*3+8) The ia64 ones have no useful comments. The 76 is a magic number and it seems strange to me that the size of JMP_BUF_SIZE depends on the OS (linux and freebsd have 76, hpux has 8*76, and vms copied the hpux example with the comment: "Maybe same as HPUX? Needs to be checked."). And anyway, these macros are only relevant for SJLJ exceptions - who uses that on ia64?? The rl78 one is, I think, a bug in the port. Ciao! Steven
On Jun 25, 2012, at 10:26 AM, Steven Bosscher wrote: > On Mon, Jun 25, 2012 at 9:13 AM, Eric Botcazou <ebotcazou@libertysurf.fr> wrote: >>> The PA and SPARC back ends do not define DONT_USE_BUILTIN_SETJMP, so >>> they also do not have to define JMP_BUF_SIZE. So: >>> >>> * config/sparc/sparc.h (JMP_BUF_SIZE): Do not define. >>> * config/pa/pa.h (JMP_BUF_SIZE): Likewise. >>> >>> OK for trunk? >> >> OK for the SPARC, thanks. > > And thanks to you for the ack! :-) > >> What about the Stormy16 and the picoChip? It seems >> like a cleanup is possible in this area for them as well. > > Right, I didn't look at the details of the uses of > DONT_USE_BUILTIN_SETJMP and JMP_BUF_SIZE but it looks like the ones in > picochip and stormy16 are redundant too: > > For picochip, this port defines DONT_USE_BUILTIN_SETJMP but in the .c > file (and after all #includes), so it is never exported and not > otherwise referenced in picochip.c, hence dead: > config/picochip/picochip.c:#undef DONT_USE_BUILTIN_SETJMP > config/picochip/picochip.c:#define DONT_USE_BUILTIN_SETJMP 1 > > stormy16 only undefines DONT_USE_BUILTIN_SETJMP (which is the default > anyway) so these two lines are redundant: > config/stormy16/stormy16.h:#undef DONT_USE_BUILTIN_SETJMP > config/stormy16/stormy16.h:#define JMP_BUF_SIZE 8 > > I will remove those lines with the same commit. > > That leaves only rl78 and ia64: > $ egrep "DONT_USE_BUILTIN_SETJMP|JMP_BUF_SIZE" config/* config/*/* > config/ia64/freebsd.h:#define JMP_BUF_SIZE 76 > config/ia64/hpux.h:#define JMP_BUF_SIZE (8 * 76) > config/ia64/ia64.h:#define DONT_USE_BUILTIN_SETJMP > config/ia64/linux.h:#define JMP_BUF_SIZE 76 > config/ia64/vms.h:#define JMP_BUF_SIZE (8 * 76) > config/rl78/rl78.h:/*#define DONT_USE_BUILTIN_SETJMP 1*/ > config/rl78/rl78.h:#undef DONT_USE_BUILTIN_SETJMP > config/rl78/rl78.h:#define JMP_BUF_SIZE (8*3+8) > > The ia64 ones have no useful comments. The 76 is a magic number and it > seems strange to me that the size of JMP_BUF_SIZE depends on the OS > (linux and freebsd have 76, hpux has 8*76, and vms copied the hpux > example with the comment: "Maybe same as HPUX? Needs to be > checked."). And anyway, these macros are only relevant for SJLJ > exceptions - who uses that on ia64?? FTR, until recently I think it was not possible to use SJLJ on ia64 due to a typo. On hpux, the definition of jmp_buf is: # define _JBLEN 320 typedef __float80 jmp_buf[_JBLEN/4]; which looks weird... Tristan.
> Right, I didn't look at the details of the uses of > DONT_USE_BUILTIN_SETJMP and JMP_BUF_SIZE but it looks like the ones in > picochip and stormy16 are redundant too: > > For picochip, this port defines DONT_USE_BUILTIN_SETJMP but in the .c > file (and after all #includes), so it is never exported and not > otherwise referenced in picochip.c, hence dead: > config/picochip/picochip.c:#undef DONT_USE_BUILTIN_SETJMP > config/picochip/picochip.c:#define DONT_USE_BUILTIN_SETJMP 1 > > stormy16 only undefines DONT_USE_BUILTIN_SETJMP (which is the default > anyway) so these two lines are redundant: > config/stormy16/stormy16.h:#undef DONT_USE_BUILTIN_SETJMP > config/stormy16/stormy16.h:#define JMP_BUF_SIZE 8 That's my understanding as well. > That leaves only rl78 and ia64: > $ egrep "DONT_USE_BUILTIN_SETJMP|JMP_BUF_SIZE" config/* config/*/* > config/ia64/freebsd.h:#define JMP_BUF_SIZE 76 > config/ia64/hpux.h:#define JMP_BUF_SIZE (8 * 76) > config/ia64/ia64.h:#define DONT_USE_BUILTIN_SETJMP > config/ia64/linux.h:#define JMP_BUF_SIZE 76 > config/ia64/vms.h:#define JMP_BUF_SIZE (8 * 76) > config/rl78/rl78.h:/*#define DONT_USE_BUILTIN_SETJMP 1*/ > config/rl78/rl78.h:#undef DONT_USE_BUILTIN_SETJMP > config/rl78/rl78.h:#define JMP_BUF_SIZE (8*3+8) > > The ia64 ones have no useful comments. The 76 is a magic number and it > seems strange to me that the size of JMP_BUF_SIZE depends on the OS > (linux and freebsd have 76, hpux has 8*76, and vms copied the hpux > example with the comment: "Maybe same as HPUX? Needs to be > checked."). And anyway, these macros are only relevant for SJLJ > exceptions - who uses that on ia64?? It looks like DONT_USE_BUILTIN_SETJMP was invented for the IA-64, probably because of the Register Stack Engine. But SPARC also has register windows, albeit less sophisticated, and can do without it. Morever, the Ada compiler uses __builtin_setjmp/__builtin_longjmp internally on the host (EH is used for error recovery) and is known to work fine on IA-64/Linux, HP-UX and VMS. In the end, it would appear that DONT_USE_BUILTIN_SETJMP was a quick trick to solve specific issues that could very likely have been solved otherwise. We should probably keep it for the sake of IA-64 and get rid of it for all other architectures, documenting that it isn't to be used in normal circumstances.
Let me try again then... RL78 is confusing and it took a while to get it to work right. Please don't change it ;-)
> RL78 is confusing and it took a while to get it to work right. Please > don't change it ;-) But we can certainly remove stuff that doesn't do anything; in particular, these 3 lines /*#define DONT_USE_BUILTIN_SETJMP 1*/ #undef DONT_USE_BUILTIN_SETJMP #define JMP_BUF_SIZE (8*3+8) can be proved to be equivalent to the empty set.
> But we can certainly remove stuff that doesn't do anything; in particular, > these 3 lines > > /*#define DONT_USE_BUILTIN_SETJMP 1*/ > #undef DONT_USE_BUILTIN_SETJMP > #define JMP_BUF_SIZE (8*3+8) > > can be proved to be equivalent to the empty set. If you say so, go for it ;-)
On Mon, Jun 25, 2012 at 10:46 AM, Eric Botcazou <ebotcazou@libertysurf.fr> wrote: > It looks like DONT_USE_BUILTIN_SETJMP was invented for the IA-64, probably > because of the Register Stack Engine. But SPARC also has register windows, > albeit less sophisticated, and can do without it. Morever, the Ada compiler > uses __builtin_setjmp/__builtin_longjmp internally on the host (EH is used for > error recovery) and is known to work fine on IA-64/Linux, HP-UX and VMS. > > In the end, it would appear that DONT_USE_BUILTIN_SETJMP was a quick trick to > solve specific issues that could very likely have been solved otherwise. We > should probably keep it for the sake of IA-64 and get rid of it for all other > architectures, documenting that it isn't to be used in normal circumstances. ia64 is now the only remaining architecture that defines DONT_USE_BUILTIN_SETJMP and JMP_BUF_SIZE. If __builtin_setjmp actually does work for ia64, why should we keep DONT_USE_BUILTIN_SETJMP? Could it break user code somehow? Ciao! Steven
On 06/26/2012 01:55 AM, Steven Bosscher wrote: > If __builtin_setjmp actually does work for ia64, why should we keep > DONT_USE_BUILTIN_SETJMP? Could it break user code somehow? It's an ABI change for anyone using --enable-sjlj-exceptions. But I don't know who that would be... r~
On 6/26/2012 11:38 AM, Richard Henderson wrote: > On 06/26/2012 01:55 AM, Steven Bosscher wrote: >> If __builtin_setjmp actually does work for ia64, why should we keep >> DONT_USE_BUILTIN_SETJMP? Could it break user code somehow? > It's an ABI change for anyone using --enable-sjlj-exceptions. > But I don't know who that would be... SJLJ exceptions are forced for hpux10. It might have been a bug to not define DONT_USE_BUILTIN_SETJMP but nobody complained as far as I know. Dave
On Tue, Jun 26, 2012 at 7:09 PM, John David Anglin <dave.anglin@bell.net> wrote: > On 6/26/2012 11:38 AM, Richard Henderson wrote: >> >> On 06/26/2012 01:55 AM, Steven Bosscher wrote: >>> >>> If __builtin_setjmp actually does work for ia64, why should we keep >>> DONT_USE_BUILTIN_SETJMP? Could it break user code somehow? >> >> It's an ABI change for anyone using --enable-sjlj-exceptions. >> But I don't know who that would be... > > SJLJ exceptions are forced for hpux10. It might have been a bug to not > define > DONT_USE_BUILTIN_SETJMP but nobody complained as far as I know. Did hpux10 even ever run on ia64? Ciao! Steven
On 6/26/2012 1:21 PM, Steven Bosscher wrote: > On Tue, Jun 26, 2012 at 7:09 PM, John David Anglin <dave.anglin@bell.net> wrote: >> On 6/26/2012 11:38 AM, Richard Henderson wrote: >>> On 06/26/2012 01:55 AM, Steven Bosscher wrote: >>>> If __builtin_setjmp actually does work for ia64, why should we keep >>>> DONT_USE_BUILTIN_SETJMP? Could it break user code somehow? >>> It's an ABI change for anyone using --enable-sjlj-exceptions. >>> But I don't know who that would be... >> SJLJ exceptions are forced for hpux10. It might have been a bug to not >> define >> DONT_USE_BUILTIN_SETJMP but nobody complained as far as I know. > Did hpux10 even ever run on ia64? Not that I know of. I was just thinking that __builtin_setjmp/__builtin_longjmp might not interwork with the libc versions on hpux10. Dave
On 06/26/2012 10:36 AM, John David Anglin wrote: > I was just thinking that __builtin_setjmp/__builtin_longjmp might not interwork with the > libc versions on hpux10. They don't need to. r~
On Jun 26, 2012, at 1:55 AM, Steven Bosscher wrote: > On Mon, Jun 25, 2012 at 10:46 AM, Eric Botcazou > <ebotcazou@libertysurf.fr> wrote: >> It looks like DONT_USE_BUILTIN_SETJMP was invented for the IA-64, probably >> because of the Register Stack Engine. But SPARC also has register windows, >> albeit less sophisticated, and can do without it. Morever, the Ada compiler >> uses __builtin_setjmp/__builtin_longjmp internally on the host (EH is used for >> error recovery) and is known to work fine on IA-64/Linux, HP-UX and VMS. >> >> In the end, it would appear that DONT_USE_BUILTIN_SETJMP was a quick trick to >> solve specific issues that could very likely have been solved otherwise. We >> should probably keep it for the sake of IA-64 and get rid of it for all other >> architectures, documenting that it isn't to be used in normal circumstances. > > ia64 is now the only remaining architecture that defines > DONT_USE_BUILTIN_SETJMP and JMP_BUF_SIZE. > > If __builtin_setjmp actually does work for ia64, why should we keep > DONT_USE_BUILTIN_SETJMP? Could it break user code somehow? History is not kind: http://gcc.gnu.org/ml/gcc-patches/2002-04/msg00124.html :-) It seems everyone else has seen the error of their ways and fixed it. :-) It got moved to ia64.h, only because a few people mistakingly used it once. Though, history isn't kinda to me either: svn log -c13969 :-( I'd say, remove it, and deprecate the bit and after 2 releases, remove the whole lot. 15 years late... Sorry for the mess.
Index: config/pa/pa.h =================================================================== --- config/pa/pa.h (revision 188917) +++ config/pa/pa.h (working copy) @@ -1508,9 +1508,6 @@ do { \ of the return address. */ \ (GEN_INT (-4)) -/* The number of Pmode words for the setjmp buffer. */ -#define JMP_BUF_SIZE 50 - /* We need a libcall to canonicalize function pointers on TARGET_ELF32. */ #define CANONICALIZE_FUNCPTR_FOR_COMPARE_LIBCALL \ "__canonicalize_funcptr_for_compare" Index: config/sparc/sparc.h =================================================================== --- config/sparc/sparc.h (revision 188917) +++ config/sparc/sparc.h (working copy) @@ -1744,9 +1744,6 @@ extern int sparc_indent_opcode; #define AS_NIAGARA3_FLAG "d" #endif -/* The number of Pmode words for the setjmp buffer. */ -#define JMP_BUF_SIZE 12 - /* We use gcc _mcount for profiling. */ #define NO_PROFILE_COUNTERS 0
Hello, For targets that define DONT_USE_BUILTIN_SETJMP, the JMP_BUF_SIZE macro can be used to set the size of the exception jump buffer. The JMP_BUF_SIZE macro is not used unless DONT_USE_BUILTIN_SETJMP is defined. See gcc/except.c and libgcc/unwind-sjlj.c. The PA and SPARC back ends do not define DONT_USE_BUILTIN_SETJMP, so they also do not have to define JMP_BUF_SIZE. So: * config/sparc/sparc.h (JMP_BUF_SIZE): Do not define. * config/pa/pa.h (JMP_BUF_SIZE): Likewise. OK for trunk? The rl78 apparently doesn't know what it wants to do: /* NOTE: defined but zero means dwarf2 debugging, but sjlj EH. */ #define DWARF2_UNWIND_INFO 0 /*#define DONT_USE_BUILTIN_SETJMP 1*/ #undef DONT_USE_BUILTIN_SETJMP #define JMP_BUF_SIZE (8*3+8) But I'll leave that to an rl78 maintainer. Ciao! Steven