From 4a54cb06585f568031dfd291d0fe45979ad75e98 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 8 Jun 2023 12:12:48 -0700 Subject: [PATCH] gold: Handle R_X86_64_CODE_4_GOTPCRELX Handle R_X86_64_CODE_4_GOTPCRELX and convert mov name@GOTPCREL(%rip), %r31 to lea name@GOTPCREL(%rip), %r31 if the instruction is encoded with the REX2 prefix when possible. elfcpp/ * x86_64.h (R_X86_64_CODE_4_GOTPCRELX): New. gold/ * x86_64.cc (Target_x86_64::can_convert_mov_to_lea): Handle R_X86_64_CODE_4_GOTPCRELX. (Target_x86_64::Scan::get_reference_flags): Likewise. (Target_x86_64::Scan::local): Likewise. (Target_x86_64::Scan::possible_function_pointer_reloc): Likewise. (Target_x86_64::Scan::global): Likewise. (Target_x86_64::Relocate::relocate): Likewise. * testsuite/x86_64_mov_to_lea1.s: Add a test for R_X86_64_CODE_4_GOTPCRELX. * testsuite/x86_64_mov_to_lea2.s: Likewise. * testsuite/x86_64_mov_to_lea3.s: Likewise. * testsuite/x86_64_mov_to_lea4.s: Likewise. * testsuite/x86_64_mov_to_lea5.s: Likewise. * testsuite/x86_64_mov_to_lea.sh: Updated. --- elfcpp/x86_64.h | 6 ++++- gold/testsuite/x86_64_mov_to_lea.sh | 16 +++++++++++++ gold/testsuite/x86_64_mov_to_lea1.s | 1 + gold/testsuite/x86_64_mov_to_lea2.s | 1 + gold/testsuite/x86_64_mov_to_lea3.s | 1 + gold/testsuite/x86_64_mov_to_lea4.s | 1 + gold/testsuite/x86_64_mov_to_lea5.s | 1 + gold/x86_64.cc | 37 ++++++++++++++++++++++------- 8 files changed, 54 insertions(+), 10 deletions(-) diff --git a/elfcpp/x86_64.h b/elfcpp/x86_64.h index 0377e773071..97a87ae424d 100644 --- a/elfcpp/x86_64.h +++ b/elfcpp/x86_64.h @@ -95,9 +95,13 @@ enum R_X86_64_PC32_BND = 39, // PC relative 32 bit signed with BND prefix R_X86_64_PLT32_BND = 40, // 32 bit PLT address with BND prefix R_X86_64_GOTPCRELX = 41, // 32 bit signed PC relative offset to GOT - // without REX prefix, relaxable. + // without REX nor REX2 prefixes, relaxable. R_X86_64_REX_GOTPCRELX = 42, // 32 bit signed PC relative offset to GOT // with REX prefix, relaxable. + R_X86_64_CODE_4_GOTPCRELX = 43, // 32 bit signed PC relative offset to + // GOT if the instruction starts at 4 + // bytes before the relocation offset, + // relaxable. // GNU vtable garbage collection extensions. R_X86_64_GNU_VTINHERIT = 250, R_X86_64_GNU_VTENTRY = 251 diff --git a/gold/testsuite/x86_64_mov_to_lea.sh b/gold/testsuite/x86_64_mov_to_lea.sh index 1b30e1aa048..3e248ebec3c 100755 --- a/gold/testsuite/x86_64_mov_to_lea.sh +++ b/gold/testsuite/x86_64_mov_to_lea.sh @@ -25,20 +25,36 @@ set -e grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea1.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea1.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea2.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea2.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea3.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea3.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea4.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea4.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea5.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea5.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea6.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea6.stdout grep -q "mov 0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea7.stdout +grep -q "mov 0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea7.stdout grep -q "mov 0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea8.stdout +grep -q "mov 0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea8.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea9.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea9.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea10.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea10.stdout grep -q "mov 0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea11.stdout +grep -q "mov 0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea11.stdout grep -q "mov 0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea12.stdout +grep -q "mov 0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea12.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea13.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea13.stdout grep -q "lea -0x[a-f0-9]\+(%rip),%rax" x86_64_mov_to_lea14.stdout +grep -q "lea -0x[a-f0-9]\+(%rip),%r26" x86_64_mov_to_lea14.stdout grep -q "mov 0x[a-f0-9]\+(%rip),%eax" x86_64_mov_to_lea15.stdout +grep -q "mov 0x[a-f0-9]\+(%rip),%r26d" x86_64_mov_to_lea15.stdout grep -q "mov 0x[a-f0-9]\+(%rip),%eax" x86_64_mov_to_lea16.stdout +grep -q "mov 0x[a-f0-9]\+(%rip),%r26d" x86_64_mov_to_lea16.stdout exit 0 diff --git a/gold/testsuite/x86_64_mov_to_lea1.s b/gold/testsuite/x86_64_mov_to_lea1.s index 4dce487c3fc..298ede12f80 100644 --- a/gold/testsuite/x86_64_mov_to_lea1.s +++ b/gold/testsuite/x86_64_mov_to_lea1.s @@ -8,4 +8,5 @@ foo: .type _start, @function _start: movq foo@GOTPCREL(%rip), %rax + movq foo@GOTPCREL(%rip), %r26 .size _start, .-_start diff --git a/gold/testsuite/x86_64_mov_to_lea2.s b/gold/testsuite/x86_64_mov_to_lea2.s index 2a11b7a19f4..404f4c1dd48 100644 --- a/gold/testsuite/x86_64_mov_to_lea2.s +++ b/gold/testsuite/x86_64_mov_to_lea2.s @@ -3,4 +3,5 @@ .type _start, @function _start: movq _DYNAMIC@GOTPCREL(%rip), %rax + movq _DYNAMIC@GOTPCREL(%rip), %r26 .size _start, .-_start diff --git a/gold/testsuite/x86_64_mov_to_lea3.s b/gold/testsuite/x86_64_mov_to_lea3.s index ac43b783758..838c33edae0 100644 --- a/gold/testsuite/x86_64_mov_to_lea3.s +++ b/gold/testsuite/x86_64_mov_to_lea3.s @@ -7,4 +7,5 @@ foo: .type _start, @function _start: movq foo@GOTPCREL(%rip), %rax + movq foo@GOTPCREL(%rip), %r26 .size _start, .-_start diff --git a/gold/testsuite/x86_64_mov_to_lea4.s b/gold/testsuite/x86_64_mov_to_lea4.s index 37bee32bb4e..a68a4cf0d19 100644 --- a/gold/testsuite/x86_64_mov_to_lea4.s +++ b/gold/testsuite/x86_64_mov_to_lea4.s @@ -9,4 +9,5 @@ foo: .type _start, @function _start: movq foo@GOTPCREL(%rip), %rax + movq foo@GOTPCREL(%rip), %r26 .size _start, .-_start diff --git a/gold/testsuite/x86_64_mov_to_lea5.s b/gold/testsuite/x86_64_mov_to_lea5.s index e793a2b9b73..e818989deb7 100644 --- a/gold/testsuite/x86_64_mov_to_lea5.s +++ b/gold/testsuite/x86_64_mov_to_lea5.s @@ -9,4 +9,5 @@ foo: .type _start, @function _start: movl foo@GOTPCREL+4(%rip), %eax + movl foo@GOTPCREL+4(%rip), %r26d .size _start, .-_start diff --git a/gold/x86_64.cc b/gold/x86_64.cc index 928dfa8ea34..b7be9bf0d48 100644 --- a/gold/x86_64.cc +++ b/gold/x86_64.cc @@ -1053,8 +1053,9 @@ class Target_x86_64 : public Sized_target gold_assert(gsym != NULL); // We cannot do the conversion unless it's one of these relocations. if (r_type != elfcpp::R_X86_64_GOTPCREL - && r_type != elfcpp::R_X86_64_GOTPCRELX - && r_type != elfcpp::R_X86_64_REX_GOTPCRELX) + && r_type != elfcpp::R_X86_64_GOTPCRELX + && r_type != elfcpp::R_X86_64_REX_GOTPCRELX + && r_type != elfcpp::R_X86_64_CODE_4_GOTPCRELX) return false; // We cannot convert references to IFUNC symbols, or to symbols that // are not local to the current module. @@ -2971,6 +2972,7 @@ Target_x86_64::Scan::get_reference_flags(unsigned int r_type) case elfcpp::R_X86_64_GOTPCREL: case elfcpp::R_X86_64_GOTPCRELX: case elfcpp::R_X86_64_REX_GOTPCRELX: + case elfcpp::R_X86_64_CODE_4_GOTPCRELX: case elfcpp::R_X86_64_GOTPLT64: // Absolute in GOT. return Symbol::ABSOLUTE_REF; @@ -3251,6 +3253,7 @@ Target_x86_64::Scan::local(Symbol_table* symtab, case elfcpp::R_X86_64_GOTPCREL: case elfcpp::R_X86_64_GOTPCRELX: case elfcpp::R_X86_64_REX_GOTPCRELX: + case elfcpp::R_X86_64_CODE_4_GOTPCRELX: case elfcpp::R_X86_64_GOTPLT64: { // The symbol requires a GOT section. @@ -3261,21 +3264,30 @@ Target_x86_64::Scan::local(Symbol_table* symtab, // mov foo@GOTPCREL(%rip), %reg // to lea foo(%rip), %reg. // in Relocate::relocate. + size_t r_offset = reloc.get_r_offset(); if (!parameters->incremental() - && (r_type == elfcpp::R_X86_64_GOTPCREL - || r_type == elfcpp::R_X86_64_GOTPCRELX - || r_type == elfcpp::R_X86_64_REX_GOTPCRELX) + && (((r_type == elfcpp::R_X86_64_GOTPCREL + || r_type == elfcpp::R_X86_64_GOTPCRELX + || r_type == elfcpp::R_X86_64_REX_GOTPCRELX) + && r_offset >= 2) + || (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX + && r_offset >= 4)) && reloc.get_r_addend() == -4 - && reloc.get_r_offset() >= 2 && !is_ifunc) { section_size_type stype; const unsigned char* view = object->section_contents(data_shndx, &stype, true); - if (view[reloc.get_r_offset() - 2] == 0x8b) + if (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX + && view[r_offset - 4] != 0xd5) + goto need_got; + + if (view[r_offset - 2] == 0x8b) break; } +need_got: + // The symbol requires a GOT entry. unsigned int r_sym = elfcpp::elf_r_sym(reloc.get_r_info()); @@ -3498,6 +3510,7 @@ Target_x86_64::Scan::possible_function_pointer_reloc( case elfcpp::R_X86_64_GOTPCREL: case elfcpp::R_X86_64_GOTPCRELX: case elfcpp::R_X86_64_REX_GOTPCRELX: + case elfcpp::R_X86_64_CODE_4_GOTPCRELX: case elfcpp::R_X86_64_GOTPLT64: { return true; @@ -3714,6 +3727,7 @@ Target_x86_64::Scan::global(Symbol_table* symtab, case elfcpp::R_X86_64_GOTPCREL: case elfcpp::R_X86_64_GOTPCRELX: case elfcpp::R_X86_64_REX_GOTPCRELX: + case elfcpp::R_X86_64_CODE_4_GOTPCRELX: case elfcpp::R_X86_64_GOTPLT64: { // The symbol requires a GOT entry. @@ -3736,8 +3750,12 @@ Target_x86_64::Scan::global(Symbol_table* symtab, size_t r_offset = reloc.get_r_offset(); if (!parameters->incremental() && reloc.get_r_addend() == -4 - && r_offset >= 2 - && Target_x86_64::can_convert_mov_to_lea(gsym, r_type, + && ((r_type != elfcpp::R_X86_64_CODE_4_GOTPCRELX + && r_offset >= 2) + || (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX + && r_offset >= 4 + && view[r_offset - 4] == 0xd5)) + && Target_x86_64::can_convert_mov_to_lea(gsym, r_type, r_offset, &view)) break; @@ -4420,6 +4438,7 @@ Target_x86_64::Relocate::relocate( case elfcpp::R_X86_64_GOTPCREL: case elfcpp::R_X86_64_GOTPCRELX: case elfcpp::R_X86_64_REX_GOTPCRELX: + case elfcpp::R_X86_64_CODE_4_GOTPCRELX: { bool converted_p = false;