[LLVMdev] clang build (Debug+Asserts) fails with Cygwin and Mingw (ASTContext.o: File too big)

[Liviu Gheorghisan]

On 5/2/2014 11:41 PM, David Blaikie wrote:
> Any idea what all those sections are - comdat inline functions?
>
No idea, as I cannot run objdump -h on a object file that I couldn't 
build :)
  Anyhow, I have an old, successful Debug+Asserts build of clang, made 
with Mingw also, for clang revision 206070. Apparently, the ASTContext.o 
file there contained 16453 sections, not 33066, as there are today.

> Does the debug info in COFF do something weird and emit a section per
> type or function?
>
I will do a release build tomorrow and check the sections. (in my 
timezone it's night) - I will let you know!

> On Fri, May 2, 2014 at 1:11 PM, Liviu Gheorghisan <livghe at gmx.com> wrote:
>> Hello,
>>
>> After switching from a Linux development host to Windows7 with Cygwin, I
>> notice the following problem when building clang (trunk, HEAD):
>> (also happens with Mingw)
>>
>> ...
>>
>> llvm[4]: Compiling ParseInit.cpp for Debug+Asserts build
>> as:
>> /cygdrive/d/Projects/Cpp/llvm/cfgCygwin/tools/clang/lib/AST/Debug+Asserts/ASTContext.o:
>> too many sections (33066)
>> /tmp/ccmtDH7w.s: Assembler messages:
>> /tmp/ccmtDH7w.s: Fatal error: can't write
>> /cygdrive/d/Projects/Cpp/llvm/cfgCygwin/tools/clang/lib/AST/Debug+Asserts/ASTContext.o:
>> File too big
>> as:
>> /cygdrive/d/Projects/Cpp/llvm/cfgCygwin/tools/clang/lib/AST/Debug+Asserts/ASTContext.o:
>> too many sections (33066)
>> /tmp/ccmtDH7w.s: Fatal error: can't close
>> /cygdrive/d/Projects/Cpp/llvm/cfgCygwin/tools/clang/lib/AST/Debug+Asserts/ASTContext.o:
>> File too big
>> /cygdrive/d/Projects/Cpp/llvm/Makefile.rules:1509: recipe for target
>> '/cygdrive/d/Projects/Cpp/llvm/cfgCygwin/tools/clang/lib/AST/Debug+Asserts/ASTContext.o'
>> failed
>> make[4]: ***
>> [/cygdrive/d/Projects/Cpp/llvm/cfgCygwin/tools/clang/lib/AST/Debug+Asserts/ASTContext.o]
>> Error 1
>> make[4]: Leaving directory
>> '/cygdrive/d/Projects/Cpp/llvm/cfgCygwin/tools/clang/lib/AST'
>> /cygdrive/d/Projects/Cpp/llvm/Makefile.rules:936: recipe for target
>> 'AST/.makeall' failed
>> make[3]: *** [AST/.makeall] Error 2
>>
>> ...
>>
>>
>> The reason for this seems to be that the COFF object format in Windows only
>> supports a maximum of 2^15 sections (32768) for obj files.
>>
>> To work around this issue, Microsoft's compiler cl has a flag called /bigobj
>> that allocates 32 bits in order to store the number of sections (instead of
>> 16 bits, as this standard specifies:
>> http://msdn.microsoft.com/en-us/library/gg463119.aspx )
>>
>> Also check this for /bigobj:
>> http://msdn.microsoft.com/en-us/library/ms173499.aspx
>>
>> Anybody else having this problem with Mingw/Cygwin? If yes, how did you
>> overcome it?
>>
>> My Cygwin version is this:
>> $ uname -a
>> CYGWIN_NT-6.1 livghe-i5 1.7.29(0.272/5/3) 2014-04-07 13:46 x86_64 Cygwin
>>
>> The only option I currently see is to split the mammoth cpp file
>> (ASTContext.cpp)  in 2 parts, or to get rid of the debug info (not desired).
>>
>>
>> --
>> Best Regards,
>> -Liviu
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-- 
Best Regards,
-Liviu