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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hi Mehdi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">GCC LTO seems support large code model in my side as below, if the code model is linker specific, does the GCC LTO use a special linker which is different from
the one in GNU Binutils?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">I’m a bit surprised if both OS X ld64 and gold plugin do not support large code model in LTO. Since modern system widely use the 64bit, the code need to run in
high address (larger than 2 GB) is a reasonable requirement.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">$ gcc -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto_gcc.bin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">$ objdump -dS codemodel1_large_lto_gcc.bin<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">int main(int argc, const char* argv[])<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">{<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 40048b: 55 push %rbp<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 40048c: 48 89 e5 mov %rsp,%rbp<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 40048f: 48 83 ec 20 sub $0x20,%rsp<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 400493: 89 7d ec mov %edi,-0x14(%rbp)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 400496: 48 89 75 e0 mov %rsi,-0x20(%rbp)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> int t = global_func(argc);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 40049a: 8b 45 ec mov -0x14(%rbp),%eax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 40049d: 89 c7 mov %eax,%edi<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 40049f: 48 b8 76 04 40 00 00 movabs $0x400476,%rax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004a6: 00 00 00<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004a9: ff d0 callq *%rax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004ab: 89 45 fc mov %eax,-0x4(%rbp)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> t += global_arr[7];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004ae: 48 b8 20 09 60 00 00 movabs $0x600920,%rax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004b5: 00 00 00<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004b8: 8b 40 1c mov 0x1c(%rax),%eax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004bb: 01 45 fc add %eax,-0x4(%rbp)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> t += static_arr[7];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004be: 48 b8 c0 0a 60 00 00 movabs $0x600ac0,%rax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004c5: 00 00 00<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004c8: 8b 40 1c mov 0x1c(%rax),%eax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004cb: 01 45 fc add %eax,-0x4(%rbp)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> t += global_arr_big[7];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004ce: 48 b8 60 0c 60 00 00 movabs $0x600c60,%rax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004d5: 00 00 00<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004d8: 8b 40 1c mov 0x1c(%rax),%eax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004db: 01 45 fc add %eax,-0x4(%rbp)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> t += static_arr_big[7];<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004de: 48 b8 a0 19 63 00 00 movabs $0x6319a0,%rax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 4004e5: 00 00 00<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004e8: 8b 40 1c mov 0x1c(%rax),%eax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004eb: 01 45 fc add %eax,-0x4(%rbp)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> return t;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> 4004ee: 8b 45 fc mov -0x4(%rbp),%eax<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">}<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Steven Shi</span></b><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Intel\SSG\STO\UEFI Firmware</span></b><b><span style="font-family:"Arial",sans-serif;color:#1F497D"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Arial",sans-serif;color:#1F497D"><o:p> </o:p></span></b></p>
<p class="MsoNormal" style="text-align:justify"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#1F497D">Tel: +86 021-61166522<o:p></o:p></span></p>
<p class="MsoNormal" style="text-align:justify"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#1F497D">iNet: 821-6522<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><a name="_____replyseparator"></a><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> mehdi.amini@apple.com [mailto:mehdi.amini@apple.com]
<br>
<b>Sent:</b> Monday, May 30, 2016 4:28 AM<br>
<b>To:</b> Shi, Steven <steven.shi@intel.com><br>
<b>Cc:</b> Umesh Kalappa <umesh.kalappa0@gmail.com>; eliben@gmail.com; llvm-dev <llvm-dev@lists.llvm.org>; cfe-dev@lists.llvm.org; Rafael Espíndola <rafael.espindola@gmail.com><br>
<b>Subject:</b> Re: [cfe-dev] [llvm-dev] How to debug if LTO generate wrong code?<o:p></o:p></span></p>
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</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal">On May 29, 2016, at 7:36 AM, Shi, Steven <<a href="mailto:steven.shi@intel.com">steven.shi@intel.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Hi Mehdi,<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">After deeper debug, I found my firmware LTO wrong code issue is related to X64 code model (-mcmodel=large) is always overridden as small (-mcmodel=small) if LTO build. And
I don't know how to correctly specific the large code model for my X64 firmware LTO build. Appreciate if you could let me know it.<span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">You know, parts of my Uefi firmware (BIOS) have to been loaded to run in high address (larger than 2 GB) at the very beginning, and I need the code makes absolutely no assumptions
about the addresses and data sections. But current LLVM LTO seems stick to use the small code model and generate many code with 32-bit RIP-relative addressing, which cause CPU exceptions when run in address larger than 2GB.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Below, I just simply reuse the Eli's codemodel1.c example (link:<span class="apple-converted-space"> </span><a href="http://eli.thegreenplace.net/2012/01/03/understanding-the-x64-code-models"><span style="color:#954F72">http://eli.thegreenplace.net/2012/01/03/understanding-the-x64-code-models</span></a>)
to show the LLVM LTO code model issue.<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">$ clang -g -O0 codemodel1.c -mcmodel=large -o codemodel1_large.bin<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">$ clang -g -O0 codemodel1.c -mcmodel=small -o codemodel1_small.bin<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">$ clang -g -O0 -flto codemodel1.c -mcmodel=large -o codemodel1_large_lto.bin<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">$ clang -g -O0 -flto codemodel1.c -mcmodel=small -o codemodel1_small_lto.bin<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">You will see the codemodel1_large_lto.bin and codemodel1_small_lto.bin are exactly the same!<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">And if you disassemble the codemodel1_large_lto.bin, you will see it uses the small code model (32-bit RIP-relative), not large, to do addressing as below.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">$ objdump -dS codemodel1_large_lto.bin<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">int main(int argc, const char* argv[])<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">{<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 4004f0: 55 push %rbp<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 4004f1: 48 89 e5 mov %rsp,%rbp<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 4004f4: 48 83 ec 20 sub $0x20,%rsp<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 4004f8: c7 45 fc 00 00 00 00 movl $0x0,-0x4(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 4004ff: 89 7d f8 mov %edi,-0x8(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400502: 48 89 75 f0 mov %rsi,-0x10(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> int t = global_func(argc);<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400506: 8b 7d f8 mov -0x8(%rbp),%edi<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 400509: e8 d2 ff ff ff callq 4004e0 <global_func></span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 40050e: 89 45 ec mov %eax,-0x14(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> t += global_arr[7];<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 400511: 8b 04 25 4c 10 60 00 mov 0x60104c,%eax</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400518: 03 45 ec add -0x14(%rbp),%eax<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 40051b: 89 45 ec mov %eax,-0x14(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> t += static_arr[7];<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 40051e: 8b 04 25 dc 11 60 00 mov 0x6011dc,%eax</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400525: 03 45 ec add -0x14(%rbp),%eax<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400528: 89 45 ec mov %eax,-0x14(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> t += global_arr_big[7];<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 40052b: 8b 04 25 6c 13 60 00 mov 0x60136c,%eax</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400532: 03 45 ec add -0x14(%rbp),%eax<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400535: 89 45 ec mov %eax,-0x14(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> t += static_arr_big[7];<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:red"> 400538: 8b 04 25 ac 20 63 00 mov 0x6320ac,%eax</span><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 40053f: 03 45 ec add -0x14(%rbp),%eax<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400542: 89 45 ec mov %eax,-0x14(%rbp)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> return t;<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400545: 8b 45 ec mov -0x14(%rbp),%eax<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 400548: 48 83 c4 20 add $0x20,%rsp<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 40054c: 5d pop %rbp<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 40054d: c3 retq<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> 40054e: 66 90 xchg %ax,%ax<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">So, does LTO support large code model? How to correctly specify the LTO code model option?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Same answer as before: LTO is setup by the linker, so the option for that, if it exists, will be linker specific.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">As far as I can tell, neither libLTO-based linker (ld64 on OS X for example), neither the gold plugin supports such an option and the code model is always "default". <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I don't know about lld, CC Rafael about that.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal">Mehdi<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Steven Shi<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Intel\SSG\STO\UEFI Firmware<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">Tel: +86 021-61166522<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">iNet: 821-6522<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> -----Original Message-----<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> From:<span class="apple-converted-space"> </span><a href="mailto:mehdi.amini@apple.com"><span style="color:#954F72">mehdi.amini@apple.com</span></a><span class="apple-converted-space"> </span>[<a href="mailto:mehdi.amini@apple.com"><span style="color:#954F72">mailto:mehdi.amini@apple.com</span></a>]<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> Sent: Wednesday, May 18, 2016 4:02 AM<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> To: Umesh Kalappa <<a href="mailto:umesh.kalappa0@gmail.com"><span style="color:#954F72">umesh.kalappa0@gmail.com</span></a>><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> Cc: Shi, Steven <<a href="mailto:steven.shi@intel.com"><span style="color:#954F72">steven.shi@intel.com</span></a>>; llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org"><span style="color:#954F72">llvm-dev@lists.llvm.org</span></a>>;<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><a href="mailto:cfe-dev@lists.llvm.org"><span style="color:#954F72">cfe-dev@lists.llvm.org</span></a><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> Subject: Re: [cfe-dev] [llvm-dev] How to debug if LTO generate wrong code?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> > On May 17, 2016, at 11:21 AM, Umesh Kalappa<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> <<a href="mailto:umesh.kalappa0@gmail.com"><span style="color:windowtext;text-decoration:none">umesh.kalappa0@gmail.com</span></a>> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> ><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> > Steven,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> ><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> > As mehdi stated , the optimisation level is specific to linker and it<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> > enables Inter-Pro opts passes ,please refer function<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> To be very clear: the -O option may trigger *linker* optimizations as well,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> independently of LTO.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> --<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">> Mehdi<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">><span class="apple-converted-space"> </span><o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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