https://gcc.gnu.org/bugzilla/show_bug.cgi?id=35513
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by H.J. Lu <h...@gcc.gnu.org>: https://gcc.gnu.org/g:ab0b5fbfe90168d2e470aefb19e0cf31526290bc commit r12-7126-gab0b5fbfe90168d2e470aefb19e0cf31526290bc Author: H.J. Lu <hjl.to...@gmail.com> Date: Sat Jun 19 05:12:48 2021 -0700 x86: Add -m[no-]direct-extern-access Add -m[no-]direct-extern-access and nodirect_extern_access attribute. -mdirect-extern-access is the default. With nodirect_extern_access attribute, GOT is always used to access undefined data and function symbols with nodirect_extern_access attribute, including in PIE and non-PIE. With -mno-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 -mno-direct-extern-access to avoid copy relocation. 4. Add ix86_reloc_rw_mask for TARGET_ASM_RELOC_RW_MASK to avoid copy relocation with -mno-direct-extern-access. gcc/ PR target/35513 PR target/100593 * config/i386/gnu-property.cc: Include "i386-protos.h". (file_end_indicate_exec_stack_and_gnu_property): Generate a GNU_PROPERTY_1_NEEDED note for -mno-direct-extern-access or nodirect_extern_access attribute. * config/i386/i386-options.cc (handle_nodirect_extern_access_attribute): New function. (ix86_attribute_table): Add nodirect_extern_access attribute. * config/i386/i386-protos.h (ix86_force_load_from_GOT_p): Add a bool argument. (ix86_has_no_direct_extern_access): New. * config/i386/i386.cc (ix86_has_no_direct_extern_access): New. (ix86_force_load_from_GOT_p): Add a bool argument to indicate call operand. Force non-call load from GOT for -mno-direct-extern-access or nodirect_extern_access attribute. (legitimate_pic_address_disp_p): Avoid copy relocation in PIE for -mno-direct-extern-access or nodirect_extern_access attribute. (ix86_print_operand): Pass true to ix86_force_load_from_GOT_p for call operand. (asm_preferred_eh_data_format): Use PC-relative format for -mno-direct-extern-access to avoid copy relocation. Check ptr_mode instead of TARGET_64BIT when selecting DW_EH_PE_sdata4. (ix86_binds_local_p): Set ix86_has_no_direct_extern_access to true for -mno-direct-extern-access or nodirect_extern_access attribute. Don't treat protected data as extern and avoid copy relocation on common symbol with -mno-direct-extern-access or nodirect_extern_access attribute. (ix86_reloc_rw_mask): New to avoid copy relocation for -mno-direct-extern-access. (TARGET_ASM_RELOC_RW_MASK): New. * config/i386/i386.opt: Add -mdirect-extern-access. * doc/extend.texi: Document nodirect_extern_access attribute. * doc/invoke.texi: Document -m[no-]direct-extern-access. gcc/testsuite/ PR target/35513 PR target/100593 * g++.target/i386/pr35513-1.C: New file. * g++.target/i386/pr35513-2.C: Likewise. * gcc.target/i386/pr35513-1a.c: Likewise. * gcc.target/i386/pr35513-1b.c: Likewise. * gcc.target/i386/pr35513-2a.c: Likewise. * gcc.target/i386/pr35513-2b.c: Likewise. * gcc.target/i386/pr35513-3a.c: Likewise. * gcc.target/i386/pr35513-3b.c: Likewise. * gcc.target/i386/pr35513-4a.c: Likewise. * gcc.target/i386/pr35513-4b.c: Likewise. * gcc.target/i386/pr35513-5a.c: Likewise. * gcc.target/i386/pr35513-5b.c: Likewise. * gcc.target/i386/pr35513-6a.c: Likewise. * gcc.target/i386/pr35513-6b.c: Likewise. * gcc.target/i386/pr35513-7a.c: Likewise. * gcc.target/i386/pr35513-7b.c: Likewise. * gcc.target/i386/pr35513-8.c: Likewise. * gcc.target/i386/pr35513-9a.c: Likewise. * gcc.target/i386/pr35513-9b.c: Likewise. * gcc.target/i386/pr35513-10a.c: Likewise. * gcc.target/i386/pr35513-10b.c: Likewise. * gcc.target/i386/pr35513-11a.c: Likewise. * gcc.target/i386/pr35513-11b.c: Likewise. * gcc.target/i386/pr35513-12a.c: Likewise. * gcc.target/i386/pr35513-12b.c: Likewise.
