x86: Add -m[no-]direct-extern-access

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.