On Mon, Jul 12, 2021 at 5:13 AM H.J. Lu <hjl.to...@gmail.com> wrote: > > On Sun, Jul 11, 2021 at 11:13 PM Richard Biener > <richard.guent...@gmail.com> wrote: > > > > On Fri, Jul 9, 2021 at 4:50 PM H.J. Lu <hjl.to...@gmail.com> wrote: > > > > > > -fdirect-extern-access is the default. With -fno-direct-extern-access: > > > > > > 1. Always use GOT to access undefined data and function symbols, > > > including in PIE and non-PIE. These will avoid copy relocations > > > in executables. This is compatible with existing executables and > > > shared libraries. > > > 2. In executable and shared library, bind symbols with the STV_PROTECTED > > > visibility locally: > > > a. The address of data symbol is the address of data body. > > > b. For systems without function descriptor, the function pointer is > > > the address of function body. > > > c. The resulting shared libraries may not be incompatible with > > > executables which have copy relocations on protected symbols or > > > use executable PLT entries as function addresses for protected > > > functions in shared libraries. > > > 3. Update asm_preferred_eh_data_format to select PC relative EH encoding > > > format with -fno-direct-extern-access to avoid copy relocation. > > > 4. Add ix86_reloc_rw_mask for TARGET_ASM_RELOC_RW_MASK to avoid copy > > > relocation with -fno-direct-extern-access. > > > > Did you check how relocations in .debug_info behave? I don't remember > > whether > > Yes, I did. I added ix86_reloc_rw_mask and use PC-relative format for > EH pointer encodings to avoid copy relocation for -fno-direct-extern-access > in read-only sections.
PING: https://gcc.gnu.org/pipermail/gcc-patches/2021-July/574846.html > > we're doing anything special there or if we just copy how we emit > > relocs in .text > > > > Richard. -- H.J.
