Re: [PATCH] Speedup gij/libjava loading on darwin

[Geoff Keating <geoffk at geoffk dot org>]

I got a nice reproducible testcase, and yes indeed, it's the linker.   
Here's what it looks like on my G4 laptop running Tiger, with  
'libgcj-1' linked with -single_module and 'libgcj-2' linked without it:

+ ld -dynamic -arch ppc -bind_at_load -multiply_defined suppress - 
weak_reference_mismatches non-weak -o ArrayClass.exe -lcrt1.o /Users/ 
geoffk/build/egcs-mainline/gcc/crt2.o -L. ArrayClassmain.o  
ArrayClass.o -lgcj-1 -liconv -lpthread -ldl -lgcc_s.1 -lSystemStubs - 
lSystem

real    0m5.186s
user    0m4.380s
sys     0m0.298s
+ ./ArrayClass.exe
class ArrayClass
class [LArrayClass;
class [[LArrayClass;
class [[[LArrayClass;
class [[[[LArrayClass;

real    0m0.430s
user    0m0.104s
sys     0m0.114s
+ ld -dynamic -arch ppc -bind_at_load -multiply_defined suppress - 
weak_reference_mismatches non-weak -o ArrayClass.exe -lcrt1.o /Users/ 
geoffk/build/egcs-mainline/gcc/crt2.o -L. ArrayClassmain.o  
ArrayClass.o -lgcj-2 -liconv -lpthread -ldl -lgcc_s.1 -lSystemStubs - 
lSystem

real    0m0.206s
user    0m0.040s
sys     0m0.080s
+ ./ArrayClass.exe
class ArrayClass
class [LArrayClass;
class [[LArrayClass;
class [[[LArrayClass;
class [[[[LArrayClass;

real    0m0.546s
user    0m0.349s
sys     0m0.130s


That's a slowdown in the link time from 0.2 seconds to 5.1 seconds!   
I've filed a Radar, number 4226076, for this.  I believe I managed to  
add both Andrew and Andreas to the Radar's security list so you can  
both see it; let me know if that actually worked.

You'll notice, though, that even on Tiger with the new dyld, the run  
time is faster with -single_module.

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