Hi there,
I use icc 12.1 SP1.11.339 on 64bit Linux and get duplicate symbol errors for symbols like .L_2__STRING.15.6 when trying to link object files that have been compiled with the -ipo option.
What I am trying to do is the following:
Our code contains hundreds of source files. For several reasons we cannot perform IPO on all of the files simultaneously. What we instead want to do is to package the files into a few "modules", perform IPO on each module, create one object file per module, and then link with these module object files (eventually the module object files will go into a static library that is shipped to the customer). So far everything but linking the application works well. Here is what I am doing:
First I compile each source file individually:
icc -ipo -vec-report0 -O -fPIC -fno-strict-aliasing -fvisibility=hidden -Wall -Wmissing-prototypes -Wmissing-declarations -Wshadow -fno-builtin-strlen -fno-builtin-strcat -fno-builtin-strcmp -fno-builtin-strcpy -fno-builtin-strncat -fno-builtin-strncmp -fno-builtin-strrchr -c -o file.o file.c
Next I perform an incremental link to combine multiple object files into one module object file
icc -diag-disable 1419 -w1 -Wcheck -vec-report0 -O -fPIC -fno-strict-aliasing -fvisibility=hidden -Wall -Wmissing-prototypes -Wmissing-declarations -Wshadow -fno-builtin-strlen -fno-builtin-strcat -fno-builtin-strcmp -fno-builtin-strcpy -fno-builtin-strncat -fno-builtin-strncmp -fno-builtin-strrchr -Wl,-i -nostdlib -o .module1.o file1.o ... filen.o ipo: remark #11000: performing multi-file optimizations ipo-1: remark #11006: generating object file /tmp/ipo_iccAP7F4c1.o ipo-2: remark #11006: generating object file /tmp/ipo_iccAP7F4c2.o ipo-3: remark #11006: generating object file /tmp/ipo_iccAP7F4c3.o ipo-4: remark #11006: generating object file /tmp/ipo_iccAP7F4c4.o
Finally, I link an application with the module object files (note that the main?.o files were also compiled with -ipo):
icc -Wl,--sort-section=name -o program main1.o ... mainn.o module1.o ... modulen.o -static-intel -Wl,--start-group /path/to/icc/12.1/composer_xe_2011_sp1.11.339/compiler/lib/intel64/libirc.a /path/to/icc/12.1/composer_xe_2011_sp1.11.339/mkl/lib/intel64/libmkl_intel_lp64.a /path/to/icc/12.1/composer_xe_2011_sp1.11.339/mkl/lib/intel64/libmkl_sequential.a /path/to/icc/12.1/composer_xe_2011_sp1.11.339/mkl/lib/intel64/libmkl_core.a -Wl,--end-group -lpthread -lm -ldl -rdynamic icc: warning #10237: -lcilkrts linked in dynamically, static library not available ipo: remark #11000: performing multi-file optimizations ipo-1: remark #11006: generating object file /tmp/ipo_iccCzLffg1.o ipo-2: remark #11006: generating object file /tmp/ipo_iccCzLffg2.o ipo-3: remark #11006: generating object file /tmp/ipo_iccCzLffg3.o ipo-4: remark #11006: generating object file /tmp/ipo_iccCzLffg4.o module1.o:(.rodata+0x1a20): multiple definition of `.L_2__STRING.15.6' /tmp/ipo_iccCzLffg2.o:(.rodata+0x5138): first defined here ld: Warning: size of symbol `.L_2__STRING.15.6' changed from 10 in /tmp/ipo_iccCzLffg2.o to 17 in .OPT/module1.o ... (many more duplicated symbols with similar names)
The value of symbol .L_2__STRING.15.6 seems to be a string constant that is defined in our source code. But why is it defined multiple times? Can anybody see what I am doing wrong? Everything works fine if I don't use -ipo to compile the individual object files.
Thanks a lot
Daniel
