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[GOLD] Edit PowerPC64 ELFv2 function entry code 

In an fixed position executable, the entry code does not need to be
PIC and can thus lose a dependency on r12.

	* powerpc.cc (Target_powerpc::Relocate::relocate): Edit ELFv2
	entry code.
	(Target_powerpc::relocate_relocs): Edit relocs to suit.
This commit is contained in:
Alan Modra 2015-12-09 10:18:44 +10:30
parent 91a65d2fe8
commit e3a7574e2e
2 changed files with 72 additions and 2 deletions
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6
gold/ChangeLog
View File

@ -1,3 +1,9 @@
2015-12-09 Alan Modra <amodra@gmail.com>
* powerpc.cc (Target_powerpc::Relocate::relocate): Edit ELFv2
entry code.
(Target_powerpc::relocate_relocs): Edit relocs to suit.
2015-12-09 Alan Modra <amodra@gmail.com>
* object.h (struct Relocate_info): Add "rr".

68
gold/powerpc.cc
View File

@ -7027,6 +7027,8 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
typedef Powerpc_relocate_functions<size, big_endian> Reloc;
typedef typename elfcpp::Swap<32, big_endian>::Valtype Insn;
typedef typename Reloc_types<elfcpp::SHT_RELA,
size, big_endian>::Reloc Reltype;
Powerpc_relobj<size, big_endian>* const object
= static_cast<Powerpc_relobj<size, big_endian>*>(relinfo->object);
Address value = 0;
@ -7700,6 +7702,55 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
}
}
break;
case elfcpp::R_POWERPC_REL16_LO:
// If we are generating a non-PIC executable, edit
// 0: addis 2,12,.TOC.-0b@ha
// addi 2,2,.TOC.-0b@l
// used by ELFv2 global entry points to set up r2, to
// lis 2,.TOC.@ha
// addi 2,2,.TOC.@l
// if .TOC. is in range. */
if (value + address - 4 + 0x80008000 <= 0xffffffff
&& relnum != 0
&& preloc != NULL
&& target->abiversion() >= 2
&& !parameters->options().output_is_position_independent()
&& gsym != NULL
&& strcmp(gsym->name(), ".TOC.") == 0)
{
const int reloc_size
= Reloc_types<elfcpp::SHT_RELA, size, big_endian>::reloc_size;
Reltype prev_rela(preloc - reloc_size);
if ((prev_rela.get_r_info()
== elfcpp::elf_r_info<size>(r_sym,
elfcpp::R_POWERPC_REL16_HA))
&& prev_rela.get_r_offset() + 4 == rela.get_r_offset()
&& prev_rela.get_r_addend() + 4 == rela.get_r_addend())
{
Insn* iview = reinterpret_cast<Insn*>(view - 2 * big_endian);
Insn insn1 = elfcpp::Swap<32, big_endian>::readval(iview - 1);
Insn insn2 = elfcpp::Swap<32, big_endian>::readval(iview);
if ((insn1 & 0xffff0000) == addis_2_12
&& (insn2 & 0xffff0000) == addi_2_2)
{
insn1 = lis_2 + ha(value + address - 4);
elfcpp::Swap<32, big_endian>::writeval(iview - 1, insn1);
insn2 = addi_2_2 + l(value + address - 4);
elfcpp::Swap<32, big_endian>::writeval(iview, insn2);
if (relinfo->rr)
{
relinfo->rr->set_strategy(relnum - 1,
Relocatable_relocs::RELOC_SPECIAL);
relinfo->rr->set_strategy(relnum,
Relocatable_relocs::RELOC_SPECIAL);
}
return true;
}
}
}
break;
}
}
@ -8357,8 +8408,21 @@ Target_powerpc<size, big_endian>::relocate_relocs(
}
else if (strategy == Relocatable_relocs::RELOC_SPECIAL)
{
if (addend >= 32768)
addend += got2_addend;
if (size == 32)
{
if (addend >= 32768)
addend += got2_addend;
}
else if (r_type == elfcpp::R_POWERPC_REL16_HA)
{
r_type = elfcpp::R_POWERPC_ADDR16_HA;
addend -= 2 * big_endian;
}
else if (r_type == elfcpp::R_POWERPC_REL16_LO)
{
r_type = elfcpp::R_POWERPC_ADDR16_LO;
addend -= 2 * big_endian + 4;
}
}
else
gold_unreachable();