On 03/09/16 17:16, Nilay Vaish wrote: > On 3 September 2016 at 09:50, Nicolas Iooss <[email protected]> > wrote: >> >> arch/x86/tools/relocs.c:460:5: error: format specifies type 'int' >> but the argument has type 'Elf64_Xword' (aka 'unsigned long') >> [-Werror,-Wformat] >> sec->shdr.sh_size); >> ^~~~~~~~~~~~~~~~~ >> arch/x86/tools/relocs.c:464:5: error: format specifies type 'int' >> but the argument has type 'Elf64_Off' (aka 'unsigned long') >> [-Werror,-Wformat] >> sec->shdr.sh_offset, strerror(errno)); >> ^~~~~~~~~~~~~~~~~~~ >> >> To support both 32-bit and 64-bit modes, add casts to long types and use >> %lu and %ld to format the numbers. >> > > Nicolas, should not just changing the format specifiers fix the > problem? How do those type casts help?
The problem is that I did not found a simple format which would make both arch/x86/tools/relocs_32.o and arch/x86/tools/relocs_64.o build without any warning. Here are the types: * When compiling relocs_32.c, sec->shdr.sh_size is of type Elf32_Word (unsigned int) and sec->shdr.sh_offset is Elf32_Off (unsigned int). * When compiling relocs_64.c, sec->shdr.sh_size is Elf64_Xword (long long unsigned int when the compiler is in 32-bit mode, long unsigned int in 64-bit mode) and sec->shdr.sh_offset is Elf64_Off (same real type as sec->shdr.sh_size). I though that casting everything to long integers was fine but now I have realized this does not take into account compiling relocs_64.c on a 32-bit host system (where HOSTCC compiles in 32-bit mode and long integers are 32-bit wide). A possible solution would be using format definitions from <inittypes.h> like PRIu32, PRIu64... in relocs.c depending on the file being compiled (relocs_32.c or relocs_64.c). What would you think of such a solution? -- Nicolas
