https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66232
--- Comment #10 from hjl at gcc dot gnu.org <hjl at gcc dot gnu.org> --- Author: hjl Date: Thu Jun 23 16:30:43 2016 New Revision: 237736 URL: https://gcc.gnu.org/viewcvs?rev=237736&root=gcc&view=rev Log: i386: Access external function via GOT slot for -fno-plt i386 psABI has been updated to clarify that R_386_GOT32X and R_386_GOT32 relocations can be used to access GOT without base register when PIC is disabled: https://groups.google.com/forum/#!topic/ia32-abi/awsRSvJOJfs 32-bit x86 assembler and linker from binutils 2.26.1 and 2.27 support call/jmp *_start@GOT cmpl $0, bar@GOT for both normal and IFUNC functions. We check if 32-bit x86 assembler and linker have the fix for: https://sourceware.org/bugzilla/show_bug.cgi?id=20244 before accessing external function via GOT slot for -fno-plt in both PIC and non-PIC modes. PR target/66232 PR target/67400 * configure.ac (as_ix86_tls_ldm_opt): Renamed to ... (as_ix86_gas_32_opt): This. (ld_ix86_tls_ldm_opt): Renamed to ... (ld_ix86_gld_32_opt): This. (R_386_TLS_LDM reloc): Updated. (R_386_GOT32X reloc): New assembler/linker check. (HAVE_AS_IX86_GOT32X): New. Defined to 1 if 32-bit assembler and linker support "jmp *_start@GOT" and "cmpl $0, bar@GOT". Otherise, defined to 0. * config.in: Regenerated. * configure: Likewise. * config/i386/i386.c (ix86_force_load_from_GOT_p): Return true if HAVE_AS_IX86_GOT32X is 1 in 32-bit mode. (ix86_legitimate_address_p): Allow UNSPEC_GOT for -fno-plt if ix86_force_load_from_GOT_p returns true. (ix86_print_operand_address_as): Also support UNSPEC_GOT if ix86_force_load_from_GOT_p returns true. (ix86_expand_move): Generate UNSPEC_GOT in 32-bit mode to load the external function address via the GOT slot. (ix86_nopic_noplt_attribute_p): Check both TARGET_64BIT and HAVE_AS_IX86_GOT32X before returning false. (ix86_output_call_insn): Generate "%!jmp/call\t*%p0@GOT" in 32-bit mode if ix86_nopic_noplt_attribute_p returns true. gcc/testsuite/ PR target/66232 PR target/67400 * gcc.target/i386/pr66232-14.c: New file. * gcc.target/i386/pr66232-15.c: Likewise. * gcc.target/i386/pr66232-16.c: Likewise. * gcc.target/i386/pr66232-17.c: Likewise. * gcc.target/i386/pr67400-1.c: Don't disable for ia32. Scan for ia32 if R_386_GOT32X relocation is supported. * gcc.target/i386/pr67400-2.c: Likewise. * gcc.target/i386/pr67400-3.c: Likewise. * gcc.target/i386/pr67400-4.c: Likewise. * gcc.target/i386/pr67400-6.c: Likewise. * gcc.target/i386/pr67400-7.c: Likewise. * lib/target-supports.exp (check_effective_target_got32x_reloc): New. Added: trunk/gcc/testsuite/gcc.target/i386/pr66232-14.c trunk/gcc/testsuite/gcc.target/i386/pr66232-15.c trunk/gcc/testsuite/gcc.target/i386/pr66232-16.c trunk/gcc/testsuite/gcc.target/i386/pr66232-17.c Modified: trunk/gcc/ChangeLog trunk/gcc/config.in trunk/gcc/config/i386/i386.c trunk/gcc/configure trunk/gcc/configure.ac trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gcc.target/i386/pr67400-1.c trunk/gcc/testsuite/gcc.target/i386/pr67400-2.c trunk/gcc/testsuite/gcc.target/i386/pr67400-3.c trunk/gcc/testsuite/gcc.target/i386/pr67400-4.c trunk/gcc/testsuite/gcc.target/i386/pr67400-6.c trunk/gcc/testsuite/gcc.target/i386/pr67400-7.c trunk/gcc/testsuite/lib/target-supports.exp
