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--- Comment #10 from Chad Joan <chadjoan@gmail.com> 2010-12-18 08:28:45 PST ---
So I thought it'd be wise to try it with both the working compiler version and the not working compiler version and see what changed in the linker string. Here it is:

chad@Hugin /mnt/sharedhd/dprojects/dtesting $ dmd trivial.d -L-v 2>
dmd2048.link
GNU ld (GNU Binutils) 2.20.1.20100303
chad@Hugin /mnt/sharedhd/dprojects/dtesting $ dmd trivial.d -L-v 2>
dmd2050.link
GNU ld (GNU Binutils) 2.20.1.20100303
chad@Hugin /mnt/sharedhd/dprojects/dtesting $ diff dmd2048.link dmd2050.link
2c2
< /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/bin/ld
--eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -pie -z now -o
trivial /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/Scrt1.o
/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crti.o
/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtbeginS.o
-L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32
-L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32
-L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32 -L/lib/../lib32
-L/usr/lib/../lib32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2
-L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2
-L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/lib
-L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../.. trivial.o -v
-L/usr/local/share/dcompilers/dmd/linux/bin/../lib -lphobos2 -lpthread -lm
-lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s
--no-as-needed /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtendS.o
/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crtn.o
---
> /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/bin/ld --eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -pie -z now -o trivial /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/Scrt1.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crti.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtbeginS.o -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32 -L/lib/../lib32 -L/usr/lib/../lib32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/lib -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../.. trivial.o -v -L/usr/local/share/dcompilers/dmd/linux/bin/../lib --export-dynamic -lphobos2 -lpthread -lm -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtendS.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crtn.o


Note the that --export-dynamic is only present in the one that segfaults. I'm in a bit of a rush at the moment and I don't remember how to mess with --export-dynamic, so that's all for now.

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--- Comment #11 from Chad Joan <chadjoan@gmail.com> 2010-12-18 08:31:23 PST ---
(In reply to comment #10)
> So I thought it'd be wise to try it with both the working compiler version and the not working compiler version and see what changed in the linker string. Here it is:
> 
> ...

Whoops, diff formatting messed things up on that second line.  Here it is again, minus the angle brackets:

-------------- dmd 2.048 --------------
/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/bin/ld --eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -pie -z now -o trivial /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/Scrt1.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crti.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtbeginS.o -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32 -L/lib/../lib32 -L/usr/lib/../lib32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/lib -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../.. trivial.o -v -L/usr/local/share/dcompilers/dmd/linux/bin/../lib -lphobos2 -lpthread -lm -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtendS.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crtn.o

-------------- dmd 2.050 --------------
/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/bin/ld --eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 -pie -z now -o trivial /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/Scrt1.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crti.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtbeginS.o -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32 -L/lib/../lib32 -L/usr/lib/../lib32 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2 -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../x86_64-pc-linux-gnu/lib -L/usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../.. trivial.o -v -L/usr/local/share/dcompilers/dmd/linux/bin/../lib --export-dynamic -lphobos2 -lpthread -lm -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/32/crtendS.o /usr/lib/gcc/x86_64-pc-linux-gnu/4.3.2/../../../../lib32/crtn.o

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Vladimir <thecybershadow@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |thecybershadow@gmail.com


--- Comment #12 from Vladimir <thecybershadow@gmail.com> 2011-02-20 15:27:04 PST ---
I just thought I'd mention that I had some similar problems with DMD on Gentoo due to bad permissions of certain libraries. Do your programs run under root? If so, check permissions for libphobos and whatever 32-bit libraries your program / libphobos uses (glibc? libstdc++?).

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--- Comment #13 from Chad Joan <chadjoan@gmail.com> 2011-09-19 23:26:19 PDT ---
I have taken another crack at this.

After some compiling of D on a roommate's non-hardened Gentoo system I found that if I recompile my gcc without the hardened useflag and then compile my D programs, the D programs won't segfault.  This round of testing was done with 64-bit DMD.

In short: using hardened GCC will trigger this.

I was pointed in this direction by observing the last line of the output of
compiling with dmd -v:
gcc main.o -o main -m64 -Xlinker
-L/usr/local/share/dcompilers/dmd/linux/bin64/../lib64 -Xlinker
-L/usr/local/share/dcompilers/dmd/linux/bin64/../lib32 -Xlinker
--no-warn-search-mismatch -Xlinker --export-dynamic -lrt -lphobos2 -lpthread
-lm

Notably, it is using gcc for its linking step.

After a bit of browsing in the DMD sources, a workaround presents itself.  DMD
just uses the CC environment variable to determine what to use for linking, so
it is possible to build an isolated non-hardened GCC and then use that to
compile D programs.  It would look like this:
CC=custom-gcc dmd -v main.d -ofmain

At some point I may bisect the older changes in DMD to find out where this regression was introduced.  I can see this ending up in the backend though, so I'm not sure I'll be able to understand the code I end up in.

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--- Comment #14 from Chad Joan <chadjoan@gmail.com> 2011-09-19 23:28:48 PDT ---
(In reply to comment #12)
> I just thought I'd mention that I had some similar problems with DMD on Gentoo due to bad permissions of certain libraries. Do your programs run under root? If so, check permissions for libphobos and whatever 32-bit libraries your program / libphobos uses (glibc? libstdc++?).

I almost forgot to mention this...

My programs still segfault under root.

Permissions are fine.

Everything works if I use a non-hardened GCC.

Thanks for the suggestions!

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Brad Roberts <braddr@puremagic.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|DMD generates programs that |gentoo's 'hardended' gcc
                   |immediately segfault.       |doesn't work with dmd


--- Comment #15 from Brad Roberts <braddr@puremagic.com> 2011-10-23 14:47:31 PDT ---
I recall some changes going in that addressed some hardening issues along the way.  I don't have a gentoo based system to test this on.  Please try the most recent beta to see if the problem still exists.

http://ftp.digitalmars.com/dmd2beta.zip

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--- Comment #16 from Chad Joan <chadjoan@gmail.com> 2011-10-24 01:33:51 PDT ---
I'm afraid it doesn't seem to be working.

It went something like this:

chad@Hugin /mnt/bulk/dprojects/helloD2 $ ls
main.d
chad@Hugin /mnt/bulk/dprojects/helloD2 $ cat main.d
import std.stdio;

void main()
{
        writefln("hello world!");
}
chad@Hugin /mnt/bulk/dprojects/helloD2 $ dmd
DMD64 D Compiler v2.056
Copyright (c) 1999-2011 by Digital Mars written by Walter Bright
Documentation: http://www.digitalmars.com/d/2.0/index.html
Usage:
  dmd files.d ... { -switch }

  files.d        D source files
  @cmdfile       read arguments from cmdfile
  -c             do not link
  -cov           do code coverage analysis
  -D             generate documentation
  -Dddocdir      write documentation file to docdir directory
  -Dffilename    write documentation file to filename
  -d             allow deprecated features
  -debug         compile in debug code
  -debug=level   compile in debug code <= level
  -debug=ident   compile in debug code identified by ident
  -debuglib=name    set symbolic debug library to name
  -defaultlib=name  set default library to name
  -deps=filename write module dependencies to filename
  -fPIC          generate position independent code
  -g             add symbolic debug info
  -gc            add symbolic debug info, pretend to be C
  -gs            always emit stack frame
  -H             generate 'header' file
  -Hddirectory   write 'header' file to directory
  -Hffilename    write 'header' file to filename
  --help         print help
  -Ipath         where to look for imports
  -ignore        ignore unsupported pragmas
  -inline        do function inlining
  -Jpath         where to look for string imports
  -Llinkerflag   pass linkerflag to link
  -lib           generate library rather than object files
  -man           open web browser on manual page
  -map           generate linker .map file
  -noboundscheck turns off array bounds checking for all functions
  -nofloat       do not emit reference to floating point
  -O             optimize
  -o-            do not write object file
  -odobjdir      write object & library files to directory objdir
  -offilename    name output file to filename
  -op            do not strip paths from source file
  -profile       profile runtime performance of generated code
  -property      enforce property syntax
  -quiet         suppress unnecessary messages
  -release       compile release version
  -run srcfile args...   run resulting program, passing args
  -unittest      compile in unit tests
  -v             verbose
  -version=level compile in version code >= level
  -version=ident compile in version code identified by ident
  -vtls          list all variables going into thread local storage
  -w             enable warnings
  -wi            enable informational warnings
  -X             generate JSON file
  -Xffilename    write JSON file to filename
chad@Hugin /mnt/bulk/dprojects/helloD2 $ dmd main.d -ofmain
/usr/lib/gcc/x86_64-pc-linux-gnu/4.4.5/../../../../x86_64-pc-linux-gnu/bin/ld:
main.o: relocation R_X86_64_32 against `.data' can not be used when making a
shared object; recompile with -fPIC
main.o: could not read symbols: Bad value
collect2: ld returned 1 exit status
--- errorlevel 1
chad@Hugin /mnt/bulk/dprojects/helloD2 $ ls
main.d  main.o
chad@Hugin /mnt/bulk/dprojects/helloD2 $ dmd main.d -ofmain -m32
/usr/lib/gcc/x86_64-pc-linux-gnu/4.4.5/../../../../x86_64-pc-linux-gnu/bin/ld:
warning: creating a DT_TEXTREL in object.
chad@Hugin /mnt/bulk/dprojects/helloD2 $ ls
main  main.d  main.o
chad@Hugin /mnt/bulk/dprojects/helloD2 $ main
main: error while loading shared libraries: cannot make segment writable for
relocation: Permission denied
chad@Hugin /mnt/bulk/dprojects/helloD2 $ sudo paxctl -m main
chad@Hugin /mnt/bulk/dprojects/helloD2 $ main
Segmentation fault
chad@Hugin /mnt/bulk/dprojects/helloD2 $ ls
main  main.d  main.o
chad@Hugin /mnt/bulk/dprojects/helloD2 $


(I don't have any other 2.056 D compilers on my system; so the part where I ran dmd to get the help text should confirm that the correct compiler is in use.)

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--- Comment #17 from Chad Joan <chadjoan@gmail.com> 2011-10-24 01:36:49 PDT ---
Created an attachment (id=1043)
More detailed info of dmd run on hardened gentoo 64-bit.

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--- Comment #18 from Chad Joan <chadjoan@gmail.com> 2011-10-24 01:37:39 PDT ---
Here is the output of dmd -v for both 32-bit (-m32) and 64-bit runs, just
in-case it helps.

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--- Comment #19 from Chad Joan <chadjoan@gmail.com> 2011-12-18 07:42:42 PST ---
Well, I tried bisecting dmd to find which change caused this.  It didn't work because this problem does not care which version of dmd I am using, it cares which RELEASE I am using.

I narrowed it down to the "-L--export-dynamic" flag in $DPATH/linux/bin64/dmd.conf

If I remove that export-dynamic flag AND rebuild druntime/phobos from scratch, everything is fine.

Of course, if I remove -L--export-dynamic AND I do NOT rebuild druntime/phobos
from scratch, I get this:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.5.3/../../../../x86_64-pc-linux-gnu/bin/ld:
main.o: relocation R_X86_64_32 against `.data' can not be used when making a
shared object; recompile with -fPIC
main.o: could not read symbols: Bad value
collect2: ld returned 1 exit status
--- errorlevel 1

I take it this means that the executable and the library must agree on whether or not to use -L--export-dynamic.  I guess it makes sense.

By removing -L--export-dynamic and building dmd/druntime/phobos all from git at v2.057, I was able to get the recent release of dmd to run on my machine without using a special GCC.

Any chance we can remove -L--export-dynamic or fix it so that it does not do this?  (I have no idea how to fix it, but removing it is easy enough!)

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