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Initial -r support.

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This commit is contained in:
Ian Lance Taylor
2008-02-06 08:13:50 +00:00
parent 0797561a54
commit 6a74a71947
18 changed files with 1696 additions and 90 deletions
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330
gold/target-reloc.h
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@@ -25,16 +25,18 @@
#include "elfcpp.h"
#include "symtab.h"
#include "reloc.h"
#include "reloc-types.h"
namespace gold
{
// This function implements the generic part of reloc scanning. This
// is an inline function which takes a class whose member functions
// local() and global() implement the machine specific part of scanning.
// We do it this way to avoidmaking a function call for each relocation,
// and to avoid repeating the generic code for each target.
// This function implements the generic part of reloc scanning. The
// template parameter Scan must be a class type which provides two
// functions: local() and global(). Those functions implement the
// machine specific part of scanning. We do it this way to
// avoidmaking a function call for each relocation, and to avoid
// repeating the generic code for each target.
template<int size, bool big_endian, typename Target_type, int sh_type,
typename Scan>
@@ -116,11 +118,9 @@ scan_relocs(
}
// This function implements the generic part of relocation processing.
// This is an inline function which take a class whose relocate()
// implements the machine specific part of relocation. We do it this
// way to avoid making a function call for each relocation, and to
// avoid repeating the generic relocation handling code for each
// target.
// The template parameter Relocate must be a class type which provides
// a single function, relocate(), which implements the machine
// specific part of a relocation.
// SIZE is the ELF size: 32 or 64. BIG_ENDIAN is the endianness of
// the data. SH_TYPE is the section type: SHT_REL or SHT_RELA.
@@ -225,6 +225,316 @@ relocate_section(
}
}
// This class may be used as a typical class for the
// Scan_relocatable_reloc parameter to scan_relocatable_relocs. The
// template parameter Classify_reloc must be a class type which
// provides a function get_size_for_reloc which returns the number of
// bytes to which a reloc applies. This class is intended to capture
// the most typical target behaviour, while still permitting targets
// to define their own independent class for Scan_relocatable_reloc.
template<int sh_type, typename Classify_reloc>
class Default_scan_relocatable_relocs
{
public:
// Return the strategy to use for a local symbol which is not a
// section symbol, given the relocation type.
inline Relocatable_relocs::Reloc_strategy
local_non_section_strategy(unsigned int, Relobj*)
{ return Relocatable_relocs::RELOC_COPY; }
// Return the strategy to use for a local symbol which is a section
// symbol, given the relocation type.
inline Relocatable_relocs::Reloc_strategy
local_section_strategy(unsigned int r_type, Relobj* object)
{
if (sh_type == elfcpp::SHT_RELA)
return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
else
{
Classify_reloc classify;
switch (classify.get_size_for_reloc(r_type, object))
{
case 0:
return Relocatable_relocs::RELOC_COPY;
case 1:
return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1;
case 2:
return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2;
case 4:
return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4;
case 8:
return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8;
default:
gold_unreachable();
}
}
}
// Return the strategy to use for a global symbol, given the
// relocation type, the object, and the symbol index.
inline Relocatable_relocs::Reloc_strategy
global_strategy(unsigned int, Relobj*, unsigned int)
{ return Relocatable_relocs::RELOC_COPY; }
};
// Scan relocs during a relocatable link. This is a default
// definition which should work for most targets.
// Scan_relocatable_reloc must name a class type which provides three
// functions which return a Relocatable_relocs::Reloc_strategy code:
// global_strategy, local_non_section_strategy, and
// local_section_strategy. Most targets should be able to use
// Default_scan_relocatable_relocs as this class.
template<int size, bool big_endian, typename Target_type, int sh_type,
typename Scan_relocatable_reloc>
void
scan_relocatable_relocs(
const General_options&,
Symbol_table*,
Layout*,
Sized_relobj<size, big_endian>* object,
unsigned int data_shndx,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
bool needs_special_offset_handling,
size_t local_symbol_count,
const unsigned char* plocal_syms,
Relocatable_relocs* rr)
{
typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
Scan_relocatable_reloc scan;
for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
{
Reltype reloc(prelocs);
Relocatable_relocs::Reloc_strategy strategy;
if (needs_special_offset_handling
&& !output_section->is_input_address_mapped(object, data_shndx,
reloc.get_r_offset()))
strategy = Relocatable_relocs::RELOC_DISCARD;
else
{
typename elfcpp::Elf_types<size>::Elf_WXword r_info =
reloc.get_r_info();
const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
if (r_sym >= local_symbol_count)
strategy = scan.global_strategy(r_type, object, r_sym);
else
{
gold_assert(plocal_syms != NULL);
typename elfcpp::Sym<size, big_endian> lsym(plocal_syms
+ r_sym * sym_size);
const unsigned int shndx = lsym.get_st_shndx();
if (shndx < elfcpp::SHN_LORESERVE
&& shndx != elfcpp::SHN_UNDEF
&& !object->is_section_included(lsym.get_st_shndx()))
{
// RELOC is a relocation against a local symbol
// defined in a section we are discarding. Discard
// the reloc. FIXME: Should we issue a warning?
strategy = Relocatable_relocs::RELOC_DISCARD;
}
else if (lsym.get_st_type() != elfcpp::STT_SECTION)
strategy = scan.local_non_section_strategy(r_type, object);
else
{
strategy = scan.local_section_strategy(r_type, object);
if (strategy != Relocatable_relocs::RELOC_DISCARD)
{
section_offset_type dummy;
Output_section* os = object->output_section(shndx,
&dummy);
os->set_needs_symtab_index();
}
}
}
}
rr->set_next_reloc_strategy(strategy);
}
}
// Relocate relocs during a relocatable link. This is a default
// definition which should work for most targets.
template<int size, bool big_endian, typename Target_type, int sh_type>
void
relocate_for_relocatable(
const Relocate_info<size, big_endian>* relinfo,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
off_t offset_in_output_section,
const Relocatable_relocs* rr,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr,
section_size_type,
unsigned char* reloc_view,
section_size_type reloc_view_size)
{
typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
typedef typename Reloc_types<sh_type, size, big_endian>::Reloc_write
Reltype_write;
const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
Sized_relobj<size, big_endian>* const object = relinfo->object;
const unsigned int local_count = object->local_symbol_count();
unsigned char* pwrite = reloc_view;
for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
{
Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
if (strategy == Relocatable_relocs::RELOC_DISCARD)
continue;
Reltype reloc(prelocs);
Reltype_write reloc_write(pwrite);
typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
const unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
const unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
// Get the new symbol index.
unsigned int new_symndx;
if (r_sym < local_count)
{
switch (strategy)
{
case Relocatable_relocs::RELOC_COPY:
new_symndx = object->symtab_index(r_sym);
gold_assert(new_symndx != -1U);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
{
// We are adjusting a section symbol. We need to find
// the symbol table index of the section symbol for
// the output section corresponding to input section
// in which this symbol is defined.
gold_assert(r_sym < local_count);
unsigned int shndx = object->local_symbol_input_shndx(r_sym);
section_offset_type dummy;
Output_section* os = object->output_section(shndx, &dummy);
gold_assert(os != NULL);
gold_assert(os->needs_symtab_index());
new_symndx = os->symtab_index();
}
break;
default:
gold_unreachable();
}
}
else
{
const Symbol* gsym = object->global_symbol(r_sym);
gold_assert(gsym != NULL);
if (gsym->is_forwarder())
gsym = relinfo->symtab->resolve_forwards(gsym);
gold_assert(gsym->has_symtab_index());
new_symndx = gsym->symtab_index();
}
// Get the new offset--the location in the output section where
// this relocation should be applied.
off_t offset = reloc.get_r_offset();
off_t new_offset;
if (offset_in_output_section != -1)
new_offset = offset + offset_in_output_section;
else
{
new_offset = output_section->output_offset(object,
relinfo->data_shndx,
offset);
gold_assert(new_offset != -1);
}
reloc_write.put_r_offset(new_offset);
reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
// Handle the reloc addend based on the strategy.
if (strategy == Relocatable_relocs::RELOC_COPY)
{
if (sh_type == elfcpp::SHT_RELA)
Reloc_types<sh_type, size, big_endian>::
copy_reloc_addend(&reloc_write,
&reloc);
}
else
{
// The relocation uses a section symbol in the input file.
// We are adjusting it to use a section symbol in the output
// file. The input section symbol refers to some address in
// the input section. We need the relocation in the output
// file to refer to that same address. This adjustment to
// the addend is the same calculation we use for a simple
// absolute relocation for the input section symbol.
const Symbol_value<size>* psymval = object->local_symbol(r_sym);
unsigned char* padd = view + offset;
switch (strategy)
{
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA:
{
typename elfcpp::Elf_types<size>::Elf_Swxword addend;
addend = Reloc_types<sh_type, size, big_endian>::
get_reloc_addend(&reloc);
addend = psymval->value(object, addend);
Reloc_types<sh_type, size, big_endian>::
set_reloc_addend(&reloc_write, addend);
}
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_1:
Relocate_functions<size, big_endian>::rel8(padd, object,
psymval);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
Relocate_functions<size, big_endian>::rel16(padd, object,
psymval);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
Relocate_functions<size, big_endian>::rel32(padd, object,
psymval);
break;
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
Relocate_functions<size, big_endian>::rel64(padd, object,
psymval);
break;
default:
gold_unreachable();
}
}
pwrite += reloc_size;
}
gold_assert(static_cast<section_size_type>(pwrite - reloc_view)
== reloc_view_size);
}
} // End namespace gold.
#endif // !defined(GOLD_TARGET_RELOC_H)