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[PATCH 2/2] Check R_386_GOT32/R_386_GOT32X without base register
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: binutils at sourceware dot org
- Date: Wed, 28 Oct 2015 09:23:40 -0700
- Subject: [PATCH 2/2] Check R_386_GOT32/R_386_GOT32X without base register
- Authentication-results: sourceware.org; auth=none
- References: <1446049420-32146-1-git-send-email-hjl dot tools at gmail dot com>
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 <hongjiu.lu@intel.com>
+
+ 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 <shenhan@google.com>
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;
--
2.4.3