From 3043c1aba16b1b5bfdf6813d90ec661988ddfa3f Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 28 Oct 2015 09:15:17 -0700 Subject: [PATCH] Check R_386_GOT32/R_386_GOT32X without base register The R_386_GOT32 and R_386_GOT32X relocations may be used without base register: movl bar@GOT, %eax Its calculation is G + A, instead of G + A - GOT, and it can only used to generate non-PIC executable. Include the .got.plt section address for R_386_GOT32 and R_386_GOT32X relocations without base register. Don't allow R_386_GOT32 and R_386_GOT32X relocations without base register when making a PIC output. PR gold/19177 * i386.cc (Target_i386::Relocate::relocate): Check R_386_GOT32 and R_386_GOT32X relocations without base register. --- gold/ChangeLog | 6 ++++++ gold/i386.cc | 28 ++++++++++++++++++++++++++-- 2 files changed, 32 insertions(+), 2 deletions(-) diff --git a/gold/ChangeLog b/gold/ChangeLog index dc1c0ea..c3cf686 100644 --- a/gold/ChangeLog +++ b/gold/ChangeLog @@ -1,3 +1,9 @@ +2015-10-28 H.J. Lu + + PR gold/19177 + * i386.cc (Target_i386::Relocate::relocate): Check R_386_GOT32 + and R_386_GOT32X relocations without base register. + 2015-10.27 Han Shen PR gold/19042 - unsupported reloc 311/312. diff --git a/gold/i386.cc b/gold/i386.cc index 36c5724..4c18de0 100644 --- a/gold/i386.cc +++ b/gold/i386.cc @@ -2790,6 +2790,8 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, } } + bool baseless; + switch (r_type) { case elfcpp::R_386_NONE: @@ -2839,6 +2841,22 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, case elfcpp::R_386_GOT32: case elfcpp::R_386_GOT32X: + baseless = (view[-1] & 0xc7) == 0x5; + // R_386_GOT32 and R_386_GOT32X don't work without base register + // when generating a position-independent output file. + if (baseless + && parameters->options().output_is_position_independent()) + { + if(gsym) + gold_error_at_location(relinfo, relnum, rel.get_r_offset(), + _("unexpected reloc %u against global symbol %s without base register in object file when generating a position-independent output file"), + r_type, gsym->demangled_name().c_str()); + else + gold_error_at_location(relinfo, relnum, rel.get_r_offset(), + _("unexpected reloc %u against local symbol without base register in object file when generating a position-independent output file"), + r_type); + } + // Convert // mov foo@GOT(%reg), %reg // to @@ -2852,8 +2870,11 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, { view[-2] = 0x8d; elfcpp::Elf_types<32>::Elf_Addr value; - value = (psymval->value(object, 0) - - target->got_plt_section()->address()); + value = psymval->value(object, 0); + // Don't subtract the .got.plt section address for baseless + // addressing. + if (!baseless) + value -= target->got_plt_section()->address(); Relocate_functions<32, false>::rel32(view, value); } else @@ -2875,6 +2896,9 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) - target->got_size()); } + // Add the .got.plt section address for baseless addressing. + if (baseless) + got_offset += target->got_plt_section()->address(); Relocate_functions<32, false>::rel32(view, got_offset); } break; -- 2.7.4