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binutils-gdb/ld/testsuite/ld-x86-64/pr22791-2c.s

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x86-64: Generate branch with PLT32 relocation Since there is no need to prepare for PLT branch on x86-64, generate R_X86_64_PLT32, instead of R_X86_64_PC32, if possible, which can be used as a marker for 32-bit PC-relative branches. To compile Linux kernel, this patch: From: "H.J. Lu" <hjl.tools@gmail.com> Subject: [PATCH] x86: Treat R_X86_64_PLT32 as R_X86_64_PC32 On i386, there are 2 types of PLTs, PIC and non-PIC. PIE and shared objects must use PIC PLT. To use PIC PLT, you need to load _GLOBAL_OFFSET_TABLE_ into EBX first. There is no need for that on x86-64 since x86-64 uses PC-relative PLT. On x86-64, for 32-bit PC-relative branches, we can generate PLT32 relocation, instead of PC32 relocation, which can also be used as a marker for 32-bit PC-relative branches. Linker can always reduce PLT32 relocation to PC32 if function is defined locally. Local functions should use PC32 relocation. As far as Linux kernel is concerned, R_X86_64_PLT32 can be treated the same as R_X86_64_PC32 since Linux kernel doesn't use PLT. is needed. It is available on hjl/plt32/master branch at https://github.com/hjl-tools/linux bfd/ PR gas/22791 * elf64-x86-64.c (is_32bit_relative_branch): Removed. (elf_x86_64_relocate_section): Check PIC relocations in PIE. Remove is_32bit_relative_branch usage. Disallow PC32 reloc against protected function in shared object. gas/ PR gas/22791 * config/tc-i386.c (need_plt32_p): New function. (output_jump): Generate BFD_RELOC_X86_64_PLT32 if possible. (md_estimate_size_before_relax): Likewise. * testsuite/gas/i386/reloc64.d: Updated. * testsuite/gas/i386/x86-64-jump.d: Likewise. * testsuite/gas/i386/x86-64-mpx-branch-1.d: Likewise. * testsuite/gas/i386/x86-64-mpx-branch-2.d: Likewise. * testsuite/gas/i386/x86-64-relax-2.d: Likewise. * testsuite/gas/i386/x86-64-relax-3.d: Likewise. * testsuite/gas/i386/ilp32/reloc64.d: Likewise. * testsuite/gas/i386/ilp32/x86-64-branch.d: Likewise. ld/ PR gas/22791 * testsuite/ld-x86-64/mpx1c.rd: Updated. * testsuite/ld-x86-64/pr22791-1.err: New file. * testsuite/ld-x86-64/pr22791-1a.c: Likewise. * testsuite/ld-x86-64/pr22791-1b.s: Likewise. * testsuite/ld-x86-64/pr22791-2.rd: Likewise. * testsuite/ld-x86-64/pr22791-2a.s: Likewise. * testsuite/ld-x86-64/pr22791-2b.c: Likewise. * testsuite/ld-x86-64/pr22791-2c.s: Likewise. * testsuite/ld-x86-64/x86-64.exp: Run PR ld/22791 tests.
2018-02-13 23:34:22 +08:00
.text
.p2align 4,,15
.globl main
.type main, @function
main:
subq $8, %rsp
call foo
xorl %eax, %eax
addq $8, %rsp
ret
.size main, .-main
.section .note.GNU-stack,"",@progbits
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