Okay, let's try this again. I've taken all the source and header files
needed to build libstdc++ and libsupc++, and put together a small and
very simple Makefile that automates the process.
Anyone interested can grab the whole thing from here:
http://goanna.cs.rmit.edu.au/~emil/dietstdcxx.1.tar.bz2 (101KB)
Usage instructions:
1) Run GNU make:
$ gmake
This will produce dietstdcxx.bc - a bytecode / object file containing all of
stdc++ and supc++ llvm-link'd together.
2) Run:
$ gmake test
This will build and run the test program.
Example:
$ gmake test
llvm-g++ -emit-llvm -c -o test.o test.cpp
llvm-link -f -o linked.o test.o dietstdcxx.bc
llvmc -o=reduced linked.o
llc -f -o=out.c -march=c reduced.bc
WARNING: this target does not support the llvm.stacksave intrinsic.
gcc out.c
./a.out
hello world
$
Things I'm doing differently compared to last time:
- almost sane build infrastructure
- building dietstdcxx with -fno-exceptions (!)
Without the llvmc step to reduce the bytecode, I get three errors in the
gcc stage:
$ llc -f -o=out2.c -march=c linked.o
WARNING: this target does not support the llvm.stacksave intrinsic.
$ gcc out2.c
/var/tmp//cc79lj1N.o(.text+0xd726d): In function
`__cxxabiv1::__pbase_type_info::__do_catch(std::type_info const*, void**,
unsigned int) const':
: undefined reference to `l182___cxa_bad_typeid'
/var/tmp//cc79lj1N.o(.data+0x19fc): undefined reference to
`std::basic_filebuf<wchar_t, std::char_traits<wchar_t>
>::seekpos(std::fpos<__mbstate_t>, std::_Ios_Openmode)'
/var/tmp//cc79lj1N.o(.data+0x1a3c): undefined reference to
`std::basic_filebuf<char, std::char_traits<char>
>::seekpos(std::fpos<__mbstate_t>, std::_Ios_Openmode)'
$
And again, using llvmc instead of llvm-link produces bad code:
$ gmake dietstdcxx.bc
$ llvm-g++ -emit-llvm -c -o test.o test.cpp
$ llvmc -o=linked test.o dietstdcxx.bc
$ lli linked.bc
Segmentation fault (core dumped)
$
Reid, you asked for a stack trace from a program generated by llvmc.
I tried this:
$ gmake clean
$ gmake [with CCFLAGS=-g]
$ llvm-g++ -g -emit-llvm -c -o test.o test.cpp
$ llvmc -native -g -o=native test.o dietstdcxx.bc
But there were no debug symbols. gdb says the problem is in main(),
but doesn't even give a line number.
It also complains about:
DW_FORM_strp pointing outside of .debug_str section [in module
/rest/dietstdcxx/native]
Did you mean something else?
--Emil
(P.S. "diet" turned out to be something of a misnomer. In the end, I
didn't really strip out any code)
