Re: [cfe-users] objc object file generated for gnustep runtime for ELF target is too big

[Perevalov Alexey via cfe-users]

I checked with lto, unfortunately, it didn't get rid of multiple .objc_protocol 
inclusions.


От: llvm-dev  от имени Perevalov Alexey via 
llvm-dev 
Отправлено: 26 сентября 2016 г. 16:33
Кому: cfe-users@lists.llvm.org; llvm-...@lists.llvm.org
Тема: [llvm-dev] objc object file generated for gnustep runtime for ELF target 
is too big

Dear community,


I'm using gnustep runtime -fobjc-runtime=gnustep with   gnustep-libobjc2 
(https://github.com/gnustep/libobjc2) and
GitHub - gnustep/libobjc2
github.com
README.md GNUstep Objective-C Runtime. The GNUstep Objective-C runtime is 
designed as a drop-in replacement for the GCC runtime. It supports both a 
legacy and a ...



Cocotron/Chameleon.

For following source file

#import 
  #import 

int main(void)
{
NSString *str = [NSString stringWithCString:"TEST"];
NSLog(@"test object %@", str);
return 0;
}

Compilation in xcode's clang
xcrun -sdk iphoneos clang -arch armv7s -mios-version-min=6.1 -c   
test_foundation.m -o test_foundation_apple.o
gives following result:
1. object file has only 3156 bytes size
2. and in disassembler only main function
3. the final executable will be 49992 bytes size in this case


But compilation in llvm's clang downloaded from 
http://llvm.org/releases/3.8.0/clang+llvm-3.8.0-x86_64-apple-darwin.tar.xz

(
clang version 3.8.0 (tags/RELEASE_380/final)
  Target: x86_64-apple-darwin15.0.0
  Thread model: posix
  )
gives another results:
1. object file has 159044 bytes size
2. in disassembler a lot of unnecessary .objc_property_list,   
.objc_method_list, .objc_protocol_list and .objc_protocol  in .bss   and 
.data section
3. the final binary size is 101837 bytes size



If comment in above sample #import http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
llvm-dev Info Page
lists.llvm.org
To see the collection of prior postings to the list, visit the llvm-dev 
Archives. Using llvm-dev: To post a message to all the list members, send ...


___
cfe-users mailing list
cfe-users@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-users

[cfe-users] objc object file generated for gnustep runtime for ELF target is too big

[Perevalov Alexey via cfe-users]

Dear community,


I'm using gnustep runtime -fobjc-runtime=gnustep with   gnustep-libobjc2 
(https://github.com/gnustep/libobjc2) and

Cocotron/Chameleon.

For following source file

#import 
  #import 

int main(void)
{
    NSString *str = [NSString stringWithCString:"TEST"];
    NSLog(@"test object %@", str);
    return 0;
}
  
Compilation in xcode's clang
xcrun -sdk iphoneos clang -arch armv7s -mios-version-min=6.1 -c   
test_foundation.m -o test_foundation_apple.o
gives following result:
1. object file has only 3156 bytes size
2. and in disassembler only main function
3. the final executable will be 49992 bytes size in this case


But compilation in llvm's clang downloaded from 
http://llvm.org/releases/3.8.0/clang+llvm-3.8.0-x86_64-apple-darwin.tar.xz

(
clang version 3.8.0 (tags/RELEASE_380/final)
  Target: x86_64-apple-darwin15.0.0
  Thread model: posix
  )
gives another results:
1. object file has 159044 bytes size
2. in disassembler a lot of unnecessary .objc_property_list,   
.objc_method_list, .objc_protocol_list and .objc_protocol  in .bss   and 
.data section
3. the final binary size is 101837 bytes size



If comment in above sample #import http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-users

Re: [cfe-users] [llvm-dev] objc object file generated for gnustep runtime for ELF target is too big

[Perevalov Alexey via cfe-users]

От: mehdi.am...@apple.com  от имени Mehdi Amini 

Отправлено: 27 сентября 2016 г. 8:46
Кому: Perevalov Alexey
Копия: cfe-users@lists.llvm.org; llvm-...@lists.llvm.org
Тема: Re: [llvm-dev] objc object file generated for gnustep runtime for ELF 
target is too big
    

> On Sep 26, 2016, at 6:33 AM, Perevalov Alexey via llvm-dev 
>  wrote:
> 
> Dear community,
> 
> 
> I'm using gnustep runtime -fobjc-runtime=gnustep with   gnustep-libobjc2 
> (https://github.com/gnustep/libobjc2) and
> 
> Cocotron/Chameleon.
> 
> For following source file
> 
> #import 
>  #import 
> 
> int main(void)
>    {
>    NSString *str = [NSString stringWithCString:"TEST"];
>    NSLog(@"test object %@", str);
>    return 0;
>    }
> 
> Compilation in xcode's clang

>Which version?

I think, it doesn't matter, due to with xcode's clang all fine

but if you intersting,

xcrun -sdk iphoneos clang --version
Apple LLVM version 7.0.0 (clang-700.1.76)
Target: x86_64-apple-darwin15.0.0
Thread model: posix

also all fine with open source llvm clang if I choose ios as -fobjc-runtime, I 
got troubles only with gnustep runtime in clang+llvm-3.8.0 and 3.9.x.

>— 
>Mehdi


> xcrun -sdk iphoneos clang -arch armv7s -mios-version-min=6.1 -c   
> test_foundation.m -o test_foundation_apple.o
> gives following result:
> 1. object file has only 3156 bytes size
> 2. and in disassembler only main function
> 3. the final executable will be 49992 bytes size in this case
> 
> 
> But compilation in llvm's clang downloaded from  
> http://llvm.org/releases/3.8.0/clang+llvm-3.8.0-x86_64-apple-darwin.tar.xz
> 
> (
> clang version 3.8.0 (tags/RELEASE_380/final)
>  Target: x86_64-apple-darwin15.0.0
>  Thread model: posix
>  )
> gives another results:
> 1. object file has 159044 bytes size
> 2. in disassembler a lot of unnecessary .objc_property_list,   
> .objc_method_list, .objc_protocol_list and .objc_protocol  in .bss   and 
> .data section
> 3. the final binary size is 101837 bytes size
> 
> 
> 
> If comment in above sample #import  file and binary file in xcode compilation will be the same,
> but size binary and object file in case of   
> clang+llvm-3.8.0-x86_64-apple-darwin compilation will be reduced   
> sufficiently:
> binary 28569 and object 36952 accordingly.
> 
> 
> 
> Looks like all protocols from UIKit.h is placed into   binary/object even 
> it's not used there.
> I got 3.9.0 from public git (branch release_39 of clang git   repository) 
> and found that all protocols interpret as definition   
> (isThisDeclarationADefinition),
> and in CGObjCGNU.cpp it's placed into object file whenever it's   used or 
> not. With the same open source compiler and   -fobjc-runtime=ios 
> protocols are not putting into
> object file even in compilation for ELF (I used -target   
> arm-linux-gnueabi).
> I used default binutil linker, not llvm's ld.ldd, due to I have problem with 
> relocation on ARM.
> I didn't use LTO, due to my linker doesn't have plugin support (I didnt' yet 
> recompile it).
> 
> Could somebody point me where to solve that problem, is it AST   
> generation stage, or linkage stage or maybe it's not a problem and just LTO 
> could be solution here?
> 
> 
> 
> 
> p.s. It's not only one issue found by me in gnustep runtime   generation, 
> and I'll report these issues in next emails.
> 
> 
> 
> 
> 
> Best regards,
>    Alexey Perevalov
> 
> ___
> LLVM Developers mailing list
> llvm-...@lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev


llvm-dev Info Page
lists.llvm.org
To see the collection of prior postings to the list, visit the llvm-dev 
Archives. Using llvm-dev: To post a message to all the list members, send ...


___
cfe-users mailing list
cfe-users@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-users

Re: [cfe-users] [llvm-dev] objc object file generated for gnustep runtime for ELF target is too big

[Perevalov Alexey via cfe-users]

От: Dr D. Chisnall  от имени David Chisnall 

Отправлено: 27 сентября 2016 г. 10:42
Кому: Perevalov Alexey
Копия: cfe-users@lists.llvm.org; llvm-...@lists.llvm.org
Тема: Re: [llvm-dev] objc object file generated for gnustep runtime for ELF 
target is too big
    
On 26 Sep 2016, at 14:33, Perevalov Alexey via llvm-dev 
 wrote:
> 
> Could somebody point me where to solve that problem, is it AST   
> generation stage, or linkage stage or maybe it's not a problem and just LTO 
> could be solution here?

>First, please don’t expect the sizes for different runtimes to be the same 
>(or, necessarily, to be even very close).  The Mac runtimes have a bit more 
>support from the linker for >various things.  To ensure that property 
>introspection is consistent without this  support, the GNUstep runtime IR 
>generation emits property definitions in all compilation units and >then 
>uniques them later.

>We’re currently working on a new ABI for the GNUstep runtime that should 
>address the size issues, but until then this looks pretty much what I’d expect.

>David

Thank you David,
I didn't expect the same size for executable file, but I got binary (real 
application) for gnustep runtime 5 times bigger than for ios runtime, and then 
I decided to figure out it.
(neither -flto nor -fdata-sections -ffunction-sections  -Wl,--gc-sections  
helped).
5x bigber it's not due to only this issue ;) I think.

For small sample (listed above in thread) I found that all protocol's 
declaration is interprets as definitions, and I see a lot of
.objc_protocol:
.long   3
.long   .L.objc_protocol_name
.long   .objc_protocol_list
.long   .objc_method_list
.long   .objc_method_list.1
.long   .objc_method_list.2
.long   .objc_method_list.3
.long   .objc_property_list
.long   .objc_property_list.4
.size   .objc_protocol, 36

.type   .L__unnamed_37,%object  @ @34
.section.rodata.str1.1,"aMS",%progbits,1
.L__unnamed_37:
.asciz  "copyWithZone:"
.size   .L__unnamed_37, 14

.type   .L__unnamed_38,%object  @ @35
...

in disassembler output and in final binary, but these protocol aren't used in 
sample. Neither front end nor linker got rid of it.
You wrote definitions will be unique, but it didn't strip out unnecessary 
.objc_protocol and depended fields.
(frankly saying after strip -s I didn't see .objc_protocol, but still find all 
selector and protocol names in strings output ;)

And it's look like a bug.





___
cfe-users mailing list
cfe-users@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-users