[M3devel] PPC_DARWIN problems, at least config/5.2.6, maybe all moot

Jay jayk123 at hotmail.com
Tue Dec 25 21:32:15 CET 2007


1)

The documentation says -fPIC is the default, so I removed it.
But it matters. It doesn't matter for gcc building C.
It matters for m3cg building Modula-3.

It is the difference between, pic:

jbook:/dev2/j/m3 jay$ cat Hello.m3 
MODULE Hello EXPORTS Main;

IMPORT IO;
BEGIN
IO.Put("Hello\n");
END Hello.

jbook:/dev2/j/m3 jay$ cat PPC_DARWIN/Hello.ms
...
        bl L_IO__Put$stub
...
.data
.picsymbol_stub
L_IO__Put$stub:
        .indirect_symbol _IO__Put
        mflr r0
        bcl 20,31,L0$_IO__Put
L0$_IO__Put:
        mflr r11
        addis r11,r11,ha16(L_IO__Put$lazy_ptr-L0$_IO__Put)
        mtlr r0
        lwz r12,lo16(L_IO__Put$lazy_ptr-L0$_IO__Put)(r11)
        mtctr r12
        addi r11,r11,lo16(L_IO__Put$lazy_ptr-L0$_IO__Put)
        bctr
.data
.lazy_symbol_pointer
L_IO__Put$lazy_ptr:
        .indirect_symbol _IO__Put
        .long dyld_stub_binding_helper

vs. non-pic just plain wow only one whole function to make a call :) :

jbook:/dev2/j/m3 jay$ cat PPC_DARWIN/Hello.ms
...
        bl _IO__Put

which nets you the likes of:

jbook:/dev2/j/m3 jay$ cm3
 -> linking prog
gcc -dynamic -o prog  _m3main.o Hello.mo -L/cm3/pkg/libm3/PPC_DARWIN -lm3 -L/cm3/pkg/m3core/PPC_DARWIN -lm3core -L/cm3/bin/../lib -lm3gcdefs
/usr/bin/ld: _m3main.o has external relocation entries in non-writable section (__TEXT,__text) for symbols:
_RTProcess__Exit
_RTLinker__AddUnit
_RTLinker__InitRuntime
collect2: ld returned 1 exit status


(Windows also only uses one instruction, through a pointer, for dynamic calls, and the compiler often prefetches the pointer.
The difference is, perhaps, that Windows aggregates all the pointers together, not sure about the other systems.. one instruction
through a pointer is true for x86 and AM64, not so of the former MIPS, PowerPC, Alpha I believe or current IA64, those
require fetching/restore the GOT/TOC (same thing? I should know the difference..)

2)
Splitting -L and -l off for shared libs matters.

ld /foo/bar.a means link to bar.a, which is a static lib, not even a stub lib or import lib like in Windows

-L/foo -lbar probes for
/foo/bar.dylib
/foo/bar.a

man ld:
       -lx    This  option  is  an abbreviation for the library name `libx.a',
              where x is a string.  If -dynamic is specified the  abbreviation
              for  the  library  name is first search as `libx.dylib' and then
              `libx.a' is searched for.  ld searches for  libraries  first  in
              any  directories specified with -L options, then in any directo-
              ries specified in the colon separated set of paths in the  envi-
              ronment  variable LD_LIBRARY_PATH, then the standard directories
              /lib, /usr/lib, and /usr/local/lib.  A library is searched  when
              its name is encountered, so the placement of the -l flag is sig-
              nificant.  If string x is of the form x.o,  then  that  file  is
              searched for in the same places, but without prepending `lib' or
              appending `.a' or `.dylib' to the filename.


3)
lastly, setting DYLD_LIBRARY_PATH=/cm3/lib
lets the full paths from one machine not matter so much on another machine.

I am going to try out:

before:
  local lib_so   = format ("lib%s.dylib", lib)
  local lib_soxx = format ("lib%s.%s.dylib", lib, version)
  local lib_pn   = LIB_INSTALL & "/" & lib_soxx

        "-install_name", lib_pn,

after:

  local lib_so   = format ("lib%s.dylib", lib)
  local lib_soxx = format ("lib%s.%s.dylib", lib, version)
  local lib_pn   = LIB_INSTALL & "/" & lib_soxx

        "-install_name", lib_soxx,

see if a path is needed or can just use leaf names.

 - Jay

From: jayk123 at hotmail.com
To: m3devel at elegosoft.com
Subject: PPC_DARWIN problems, at least config/5.2.6, maybe all moot
Date: Tue, 25 Dec 2007 12:09:31 +0000







PPC_DARWIN also has problems...at least in the config.


If you take the 5.2.6 archive, install to /dev2/cm3, accept the defaults,
claim all the missing unused libs are in /usr/lib (opengl, postgres, x11)


you end up with:


jbook:/dev2/j/m3 jay$ cat Hello.m3 


MODULE Hello EXPORTS Main;
IMPORT IO;
BEGIN
IO.Put("Hello\n");
END Hello.


jbook:/dev2/j/m3 jay$ uname -a
Darwin jbook 8.11.0 Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC Power Macintosh powerpc


jbook:/dev2/j/m3 jay$ cm3 -version
Critical Mass Modula-3 version 5.2.6
  last updated: 2003-06-27
  configuration: /cm3/bin/cm3.cfg


jbook:/dev2/j/m3 jay$ cm3
new source -> compiling Hello.m3
 -> linking prog


jbook:/dev2/j/m3 jay$ PPC_DARWIN/prog
dyld: Library not loaded: /var/tmp/cm3/lib/libm3.5.2.dylib
  Referenced from: /dev2/j/m3/PPC_DARWIN/prog
  Reason: image not found
Trace/BPT trap


jbook:/dev2/j/m3 jay$ otool -L PPC_DARWIN/prog
PPC_DARWIN/prog:
        /var/tmp/cm3/lib/libm3.5.2.dylib (compatibility version 5.0.0, current version 5.2.0)
        /Users/wagner/local/cm3/lib/libm3core.5.2.dylib (compatibility version 5.0.0, current version 5.2.0)
        /Users/wagner/local/cm3/lib/libm3gcdefs.5.2.dylib (compatibility version 5.0.0, current version 5.2.0)
        /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 88.1.10)
        /usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)


jbook:/dev2/j/m3 jay$ ls -l PPC_DARWIN/prog
-rwxr-xr-x   1 jay  admin  20264 Dec 25 04:43 PPC_DARWIN/prog


At the temporary cost of giving up dynamic linking, you can fix this by removing M3_SPLIT_LIBNAMES_IF_SHARED
and/or M3_SPLIT_LIBNAMES from cm3.cfg, yielding:


jbook:/dev2/j/m3 jay$ otool -L PPC_DARWIN/prog
PPC_DARWIN/prog:
        /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 88.1.10)


jbook:/dev2/j/m3 jay$ ls -l PPC_DARWIN/prog
-rwxr-xr-x   1 jay  admin  1388380 Dec 25 04:48 PPC_DARWIN/prog


jbook:/dev2/j/m3 jay$ PPC_DARWIN/prog
Hello


I will fix the checked in config file...even though it varies a bunch from the 5.2.6 distributed
config, it results in the same.


And, um, does everyone understand what I did with Win32 and making cminstall obsolete?
Ok to do the same on Mac OS X?
You know, it's running things out of the path and/or finding them in their "very standard" locations.
In fact, you can hard code full paths and be ok.
That is, instead of asking the user where their compiler is, hardcoding any of cc, gcc, /usr/bin/cc, /usr/bin/gcc all work fine.
Asking them where ar/ranlib are, similar, though the docs say that libtool replaced those, and ar/ranlib vs. libtool is one way
in which the checked in config and the 5.2.6 distribution's config vary. I'll try for libtool.


The only thing the user really  needs to decide is where to install to, and
the cfg file can discover their choice without any editing.


INSTALL_ROOT = path() & "/.."
BIN_INSTALL   = path() % executables


In terms of wanting to provide some configurable redirection, well, I think an advanced user can manage..
An indirect SYSTEM_CC = "cc" can be left, I guess.


You know, I dare say, that platforms have been reduced and converged enough such that..you can get rid of
Quake and move it into cm3. Um.. do any of the Unix platforms support other than gcc? Other than GNU ld?
Ok, Apple ld is not GNU ld. (Geez, it is just me or is Apple an incredible hodgepodge mess these days?
I mean both in terms of their "system architecture" and their tools. The "system architecture" reveals bunches
of similar redundant subsystems. Try reading through man ld, man ranlib, just try to understand which
flag goes with which mode, which flags are for compatibility with which OS version, and which of the
compatibility flags is either ignored or does something useful... and should I say -lGL or -framework OpenGL??)


That I don't haven't adjusted to Modula-3 and don't mind/prefer writing Quake instead. :)


Some bootstrap was provided. I should look at it, and its config.
Otherwise..I'll look into what it takes to build it all and with dynamic linking.
Perhaps the bootstrap is just fine. But the checked in config is not.


 - Jay

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