Getting GCC to compile without inserting call to memcpy

user_806557 0
Viewed 11609

I'm currently using GCC 4.5.3, compiled for PowerPC 440, and am compiling some code that doesn't require libc. I don't have any direct calls to memcpy(), but the compiler seems to be inserting one during the build.

There are linker options like -nostdlib, -nostartfiles, -nodefaultlibs but I'm unable to use them as I'm not doing the linking phase. I'm only compiling. With something like this:

$ powerpc-440-eabi-gcc -O2 -g -c -o output.o input.c

If I check the output.o with nm, I see a reference to memcpy:

$ powerpc-440-eabi-nm output.o | grep memcpy
     U memcpy
$

The GCC man page makes it clear how to remove calls to memcpy and other libc calls with the linker, but I don't want the compiler to insert them in the first place, as I'm using a completely different linker (not GNU's ld, and it doesn't know about libc).

Thanks for any help you can provide.

memcpy libc gcc compiler-construction
5 Answers

This is quite an old question, but I've hit the same issue, and none of the solutions here worked.

So I defined this function:

static __attribute__((always_inline)) inline void* imemcpy (void *dest, const void *src, size_t len) {
  char *d = dest;
  const char *s = src;
  while (len--)
    *d++ = *s++;
  return dest;
}

And then used it instead of memcpy. This has solved the inlining issue for me permanently. Not very useful if you are compiling some sort of library though.

user_111099220
Related