iinc_w instruction and hsdis build instructions ...

Mon Jan 12 14:19:14 UTC 2015

Thank you!
I tried the -Wno-error=unused-but-set-variable workaround and it seems to
have worked after running into another error [1].
I now have hsdis-amd64.so.

Regards,
Kedar
1- make CFLAGS="-Wno-error=unused-but-set-variable"
BINUTILS=binutils-2.23.2 ARCH=amd64 is the command which runs into linking
statically with libbfd.a (/tmp/ccUxTKNw.o: relocation R_X86_64_32 against
`.rodata' can not be used when making a shared object; recompile with
-fPIC). Instead of linking statically I chose to use the shared object, so,
I installed the binutils-dev package that gives the symlink
(/usr/lib/libbfd.so -> libbfd-2.24-system.so) and then used -lbfd like so:
make CFLAGS="-Wno-error=unused-but-set-variable -lbfd"
BINUTILS=binutils-2.23.2 ARCH=amd64. This seems to have fixed the build.
Hopefully I built the right hsdis so :-).

On Mon, Jan 12, 2015 at 12:14 AM, Volker Simonis <volker.simonis at gmail.com>
wrote:

> Hi Kedar,
>
> the hsdis build error is probably because of a new warning in recent
> versions of GCC. See https://gcc.gnu.org/gcc-4.6/porting_to.html
>
> Quoted from there:
>
> New warnings for unused variables and parameters
>
> The behavior of -Wall has changed and now includes the new warning
> flags -Wunused-but-set-variable and (with -Wall -Wextra)
> -Wunused-but-set-parameter. This may result in new warnings in code
> that compiled cleanly with previous versions of GCC.
>
> For example,
>
>   void fn (void)
>   {
>     int foo;
>     foo = bar ();  /* foo is never used.  */
>   }
>
> Gives the following diagnostic:
>
> warning: variable "foo" set but not used [-Wunused-but-set-variable]
>
> Although these warnings will not result in compilation failure, often
> -Wall is used in conjunction with -Werror and as a result, new
> warnings are turned into new errors.
>
> To fix, first see if the unused variable or parameter can be removed
> without changing the result or logic of the surrounding code. If not,
> annotate it with __attribute__((__unused__)).
>
> As a workaround, add -Wno-error=unused-but-set-variable or
> -Wno-error=unused-but-set-parameter.
>
> Regards,
> Volker
>
>
> On Sat, Jan 10, 2015 at 12:50 AM, kedar mhaswade
> <kedar.mhaswade at gmail.com> wrote:
> > Hello JVM developers!
> >   I hope I am posting to the right mailing list, if not, please let me
> know
> > where I should direct these two questions.
> >
> > 1) When generating the bytecode by javac-7 and javac-8, I see iinc_w
> > instruction (and javap shows subtle differences in disassembly on the
> same
> > java class file). I don't find a direct reference to this instruction at:
> > http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-6.html#jvms-6.5.
> >
> > Where should I be looking for the documentation?
> >
> > 2) I want to build hsdis on Ubuntu 14.04. I have tried with a bunch of
> > binutils versions, but it fails rather obscurely [1]. Are there any
> > instructions for a successful build on Ubuntu/Debian?
> >
> > Thanks!
> > -Kedar
> >
> > 1- /bin/bash ./libtool --tag=CC --mode=compile gcc -DHAVE_CONFIG_H -I.
> >
> -I/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd
> > -I. -I.
> >
> -I/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd
> >
> -I/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/../include
> >     -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Werror -fPIC -O -c
> > -o elf64-x86-64.lo
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c
> > libtool: compile:  gcc -DHAVE_CONFIG_H -I.
> >
> -I/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd
> > -I. -I.
> >
> -I/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd
> >
> -I/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/../include
> > -W -Wall -Wstrict-prototypes -Wmissing-prototypes -Werror -fPIC -O -c
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c
> > -o elf64-x86-64.o
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:
> > In function 'elf64_x86_64_relocate_section':
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:2394:16:
> > error: variable 'warned' set but not used
> [-Werror=unused-but-set-variable]
> >     bfd_boolean warned;
> >                 ^
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:2870:29:
> > error: variable 'type2' set but not used
> [-Werror=unused-but-set-variable]
> >      unsigned int val, type, type2;
> >                              ^
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:3116:29:
> > error: variable 'type2' set but not used
> [-Werror=unused-but-set-variable]
> >      unsigned int val, type, type2;
> >                              ^
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:3116:23:
> > error: variable 'type' set but not used [-Werror=unused-but-set-variable]
> >      unsigned int val, type, type2;
> >                        ^
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:3116:18:
> > error: variable 'val' set but not used [-Werror=unused-but-set-variable]
> >      unsigned int val, type, type2;
> >                   ^
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:3147:23:
> > error: variable 'type' set but not used [-Werror=unused-but-set-variable]
> >      unsigned int val, type;
> >                        ^
> >
> /media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/binutils-2.19.1/bfd/elf64-x86-64.c:3147:18:
> > error: variable 'val' set but not used [-Werror=unused-but-set-variable]
> >      unsigned int val, type;
> >                   ^
> > cc1: all warnings being treated as errors
> > make[4]: *** [elf64-x86-64.lo] Error 1
> > make[4]: Leaving directory
> >
> `/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/build/linux-amd64/bfd'
> > make[3]: *** [all-recursive] Error 1
> > make[3]: Leaving directory
> >
> `/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/build/linux-amd64/bfd'
> > make[2]: *** [all] Error 2
> > make[2]: Leaving directory
> >
> `/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/build/linux-amd64/bfd'
> > make[1]: *** [all-bfd] Error 2
> > make[1]: Leaving directory
> >
> `/media/kedar/2tb1/Projects/hsdis/openjdk/hotspot/src/share/tools/hsdis/build/linux-amd64'
> > make: *** [build/linux-amd64/bfd/libbfd.a] Error 2
>