// target-reloc.h -- target specific relocation support -*- C++ -*-
-// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+// Copyright (C) 2006-2018 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// avoid making 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>
+template<int size, bool big_endian, typename Target_type,
+ typename Scan, typename Classify_reloc>
inline void
scan_relocs(
Symbol_table* symtab,
size_t local_count,
const unsigned char* plocal_syms)
{
- typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
- const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
+ typedef typename Classify_reloc::Reltype Reltype;
+ const int reloc_size = Classify_reloc::reloc_size;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
Scan scan;
reloc.get_r_offset()))
continue;
- typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
- unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
- unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
+ unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
+ unsigned int r_type = Classify_reloc::get_r_type(&reloc);
if (r_sym < local_count)
{
unsigned int shndx = lsym.get_st_shndx();
bool is_ordinary;
shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
- if (is_ordinary
- && shndx != elfcpp::SHN_UNDEF
- && !object->is_section_included(shndx)
- && !symtab->is_section_folded(object, shndx))
- {
- // RELOC is a relocation against a local symbol in a
- // section we are discarding. We can ignore this
- // relocation. It will eventually become a reloc
- // against the value zero.
- //
- // FIXME: We should issue a warning if this is an
- // allocated section; is this the best place to do it?
- //
- // FIXME: The old GNU linker would in some cases look
- // for the linkonce section which caused this section to
- // be discarded, and, if the other section was the same
- // size, change the reloc to refer to the other section.
- // That seems risky and weird to me, and I don't know of
- // any case where it is actually required.
-
- continue;
- }
+ // If RELOC is a relocation against a local symbol in a
+ // section we are discarding then we can ignore it. It will
+ // eventually become a reloc against the value zero.
+ //
+ // FIXME: We should issue a warning if this is an
+ // allocated section; is this the best place to do it?
+ //
+ // FIXME: The old GNU linker would in some cases look
+ // for the linkonce section which caused this section to
+ // be discarded, and, if the other section was the same
+ // size, change the reloc to refer to the other section.
+ // That seems risky and weird to me, and I don't know of
+ // any case where it is actually required.
+ bool is_discarded = (is_ordinary
+ && shndx != elfcpp::SHN_UNDEF
+ && !object->is_section_included(shndx)
+ && !symtab->is_section_folded(object, shndx));
scan.local(symtab, layout, target, object, data_shndx,
- output_section, reloc, r_type, lsym);
+ output_section, reloc, r_type, lsym, is_discarded);
}
else
{
CB_WARNING // Print a warning.
};
-// Decide what the linker should do for relocations that refer to discarded
-// comdat sections. This decision is based on the name of the section being
-// relocated.
-
-inline Comdat_behavior
-get_comdat_behavior(const char* name)
+class Default_comdat_behavior
{
- if (Layout::is_debug_info_section(name))
- return CB_PRETEND;
- if (strcmp(name, ".eh_frame") == 0
- || strcmp(name, ".gcc_except_table") == 0)
- return CB_IGNORE;
- return CB_WARNING;
-}
+ public:
+ // Decide what the linker should do for relocations that refer to
+ // discarded comdat sections. This decision is based on the name of
+ // the section being relocated.
+
+ inline Comdat_behavior
+ get(const char* name)
+ {
+ if (Layout::is_debug_info_section(name))
+ return CB_PRETEND;
+ if (strcmp(name, ".eh_frame") == 0
+ || strcmp(name, ".gcc_except_table") == 0)
+ return CB_IGNORE;
+ return CB_WARNING;
+ }
+};
// Give an error for a symbol with non-default visibility which is not
// defined locally.
return false;
// We don't report weak symbols.
- if (sym->binding() == elfcpp::STB_WEAK)
+ if (sym->is_weak_undefined())
return false;
- // We don't report symbols defined in discarded sections.
- if (sym->is_defined_in_discarded_section())
+ // We don't report symbols defined in discarded sections,
+ // unless they're placeholder symbols that should have been
+ // provided by a plugin.
+ if (sym->is_defined_in_discarded_section() && !sym->is_placeholder())
return false;
// If the target defines this symbol, don't report it here.
return false;
}
+ // If the symbol is hidden, report it.
+ if (sym->visibility() == elfcpp::STV_HIDDEN)
+ return true;
+
// When creating a shared library, only report unresolved symbols if
// -z defs was used.
if (parameters->options().shared() && !parameters->options().defs())
// a single function, relocate(), which implements the machine
// specific part of a relocation.
+// The template parameter Relocate_comdat_behavior is a class type
+// which provides a single function, get(), which determines what the
+// linker should do for relocations that refer to discarded comdat
+// sections.
+
// 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.
// RELOCATE implements operator() to do a relocation.
// symbol for the relocation, ignoring the symbol index in the
// relocation.
-template<int size, bool big_endian, typename Target_type, int sh_type,
- typename Relocate>
+template<int size, bool big_endian, typename Target_type,
+ typename Relocate,
+ typename Relocate_comdat_behavior,
+ typename Classify_reloc>
inline void
relocate_section(
const Relocate_info<size, big_endian>* relinfo,
section_size_type view_size,
const Reloc_symbol_changes* reloc_symbol_changes)
{
- typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
- const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
+ typedef typename Classify_reloc::Reltype Reltype;
+ const int reloc_size = Classify_reloc::reloc_size;
Relocate relocate;
+ Relocate_comdat_behavior relocate_comdat_behavior;
Sized_relobj_file<size, big_endian>* object = relinfo->object;
unsigned int local_count = object->local_symbol_count();
continue;
}
- typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
- unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
- unsigned int r_type = elfcpp::elf_r_type<size>(r_info);
+ unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
const Sized_symbol<size>* sym;
// If the local symbol belongs to a section we are discarding,
// and that section is a debug section, try to find the
// corresponding kept section and map this symbol to its
- // counterpart in the kept section. The symbol must not
+ // counterpart in the kept section. The symbol must not
// correspond to a section we are folding.
bool is_ordinary;
shndx = psymval->input_shndx(&is_ordinary);
if (comdat_behavior == CB_UNDETERMINED)
{
std::string name = object->section_name(relinfo->data_shndx);
- comdat_behavior = get_comdat_behavior(name.c_str());
+ comdat_behavior = relocate_comdat_behavior.get(name.c_str());
}
if (comdat_behavior == CB_PRETEND)
{
psymval = &symval2;
}
- if (!relocate.relocate(relinfo, target, output_section, i, reloc,
- r_type, sym, psymval, view + offset,
- view_address + offset, view_size))
+ // If OFFSET is out of range, still let the target decide to
+ // ignore the relocation. Pass in NULL as the VIEW argument so
+ // that it can return quickly without trashing an invalid memory
+ // address.
+ unsigned char *v = view + offset;
+ if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
+ v = NULL;
+
+ if (!relocate.relocate(relinfo, Classify_reloc::sh_type, target,
+ output_section, i, prelocs, sym, psymval,
+ v, view_address + offset, view_size))
continue;
- if (offset < 0 || static_cast<section_size_type>(offset) >= view_size)
+ if (v == NULL)
{
gold_error_at_location(relinfo, i, offset,
_("reloc has bad offset %zu"),
gold_undefined_symbol_at_location(sym, relinfo, i, offset);
else if (sym != NULL
&& sym->visibility() != elfcpp::STV_DEFAULT
- && (sym->is_undefined() || sym->is_from_dynobj()))
+ && (sym->is_strong_undefined() || sym->is_from_dynobj()))
visibility_error(sym);
if (sym != NULL && sym->has_warning())
section_size_type view_size)
{
// Construct the ELF relocation in a temporary buffer.
- const int reloc_size = elfcpp::Elf_sizes<64>::rela_size;
+ const int reloc_size = elfcpp::Elf_sizes<size>::rela_size;
unsigned char relbuf[reloc_size];
- elfcpp::Rela<64, false> rel(relbuf);
- elfcpp::Rela_write<64, false> orel(relbuf);
+ elfcpp::Rela_write<size, big_endian> orel(relbuf);
orel.put_r_offset(r_offset);
- orel.put_r_info(elfcpp::elf_r_info<64>(0, r_type));
+ orel.put_r_info(elfcpp::elf_r_info<size>(0, r_type));
orel.put_r_addend(r_addend);
// Setup a Symbol_value for the global symbol.
- const Sized_symbol<64>* sym = static_cast<const Sized_symbol<64>*>(gsym);
- Symbol_value<64> symval;
+ const Sized_symbol<size>* sym = static_cast<const Sized_symbol<size>*>(gsym);
+ Symbol_value<size> symval;
gold_assert(sym->has_symtab_index() && sym->symtab_index() != -1U);
symval.set_output_symtab_index(sym->symtab_index());
symval.set_output_value(sym->value());
symval.set_is_ifunc_symbol();
Relocate relocate;
- relocate.relocate(relinfo, target, NULL, -1U, rel, r_type, sym, &symval,
+ relocate.relocate(relinfo, elfcpp::SHT_RELA, target, NULL,
+ -1U, relbuf, sym, &symval,
view + r_offset, address + r_offset, view_size);
}
+// A class for inquiring about properties of a relocation,
+// used while scanning relocs during a relocatable link and
+// garbage collection. This class may be used as the default
+// for SHT_RELA targets, but SHT_REL targets must implement
+// a derived class that overrides get_size_for_reloc.
+// The MIPS-64 target also needs to override the methods
+// for accessing the r_sym and r_type fields of a relocation,
+// due to its non-standard use of the r_info field.
+
+template<int sh_type_, int size, bool big_endian>
+class Default_classify_reloc
+{
+ public:
+ typedef typename Reloc_types<sh_type_, size, big_endian>::Reloc
+ Reltype;
+ typedef typename Reloc_types<sh_type_, size, big_endian>::Reloc_write
+ Reltype_write;
+ static const int reloc_size =
+ Reloc_types<sh_type_, size, big_endian>::reloc_size;
+ static const int sh_type = sh_type_;
+
+ // Return the symbol referred to by the relocation.
+ static inline unsigned int
+ get_r_sym(const Reltype* reloc)
+ { return elfcpp::elf_r_sym<size>(reloc->get_r_info()); }
+
+ // Return the type of the relocation.
+ static inline unsigned int
+ get_r_type(const Reltype* reloc)
+ { return elfcpp::elf_r_type<size>(reloc->get_r_info()); }
+
+ // Return the explicit addend of the relocation (return 0 for SHT_REL).
+ static inline typename elfcpp::Elf_types<size>::Elf_Swxword
+ get_r_addend(const Reltype* reloc)
+ { return Reloc_types<sh_type_, size, big_endian>::get_reloc_addend(reloc); }
+
+ // Write the r_info field to a new reloc, using the r_info field from
+ // the original reloc, replacing the r_sym field with R_SYM.
+ static inline void
+ put_r_info(Reltype_write* new_reloc, Reltype* reloc, unsigned int r_sym)
+ {
+ unsigned int r_type = elfcpp::elf_r_type<size>(reloc->get_r_info());
+ new_reloc->put_r_info(elfcpp::elf_r_info<size>(r_sym, r_type));
+ }
+
+ // Write the r_addend field to a new reloc.
+ static inline void
+ put_r_addend(Reltype_write* to,
+ typename elfcpp::Elf_types<size>::Elf_Swxword addend)
+ { Reloc_types<sh_type_, size, big_endian>::set_reloc_addend(to, addend); }
+
+ // Return the size of the addend of the relocation (only used for SHT_REL).
+ static unsigned int
+ get_size_for_reloc(unsigned int, Relobj*)
+ {
+ gold_unreachable();
+ return 0;
+ }
+};
+
// 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>
+// Scan_relocatable_reloc parameter to scan_relocatable_relocs.
+// 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<typename Classify_reloc>
class Default_scan_relocatable_relocs
{
public:
+ typedef typename Classify_reloc::Reltype Reltype;
+ static const int reloc_size = Classify_reloc::reloc_size;
+ static const int sh_type = Classify_reloc::sh_type;
+
+ // Return the symbol referred to by the relocation.
+ static inline unsigned int
+ get_r_sym(const Reltype* reloc)
+ { return Classify_reloc::get_r_sym(reloc); }
+
+ // Return the type of the relocation.
+ static inline unsigned int
+ get_r_type(const Reltype* reloc)
+ { return Classify_reloc::get_r_type(reloc); }
+
// Return the strategy to use for a local symbol which is not a
// section symbol, given the relocation type.
inline Relocatable_relocs::Reloc_strategy
return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
else
{
- Classify_reloc classify;
- switch (classify.get_size_for_reloc(r_type, object))
+ switch (Classify_reloc::get_size_for_reloc(r_type, object))
{
case 0:
return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
{ return Relocatable_relocs::RELOC_COPY; }
};
+// This is a strategy class used with scan_relocatable_relocs
+// and --emit-relocs.
+
+template<typename Classify_reloc>
+class Default_emit_relocs_strategy
+{
+ public:
+ typedef typename Classify_reloc::Reltype Reltype;
+ static const int reloc_size = Classify_reloc::reloc_size;
+ static const int sh_type = Classify_reloc::sh_type;
+
+ // Return the symbol referred to by the relocation.
+ static inline unsigned int
+ get_r_sym(const Reltype* reloc)
+ { return Classify_reloc::get_r_sym(reloc); }
+
+ // Return the type of the relocation.
+ static inline unsigned int
+ get_r_type(const Reltype* reloc)
+ { return Classify_reloc::get_r_type(reloc); }
+
+ // A local non-section symbol.
+ inline Relocatable_relocs::Reloc_strategy
+ local_non_section_strategy(unsigned int, Relobj*, unsigned int)
+ { return Relocatable_relocs::RELOC_COPY; }
+
+ // A local section symbol.
+ inline Relocatable_relocs::Reloc_strategy
+ local_section_strategy(unsigned int, Relobj*)
+ {
+ if (sh_type == elfcpp::SHT_RELA)
+ return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_RELA;
+ else
+ {
+ // The addend is stored in the section contents. Since this
+ // is not a relocatable link, we are going to apply the
+ // relocation contents to the section as usual. This means
+ // that we have no way to record the original addend. If the
+ // original addend is not zero, there is basically no way for
+ // the user to handle this correctly. Caveat emptor.
+ return Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_0;
+ }
+ }
+
+ // A global symbol.
+ 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
// local_section_strategy. Most targets should be able to use
// Default_scan_relocatable_relocs as this class.
-template<int size, bool big_endian, int sh_type,
- typename Scan_relocatable_reloc>
+template<int size, bool big_endian, typename Scan_relocatable_reloc>
void
scan_relocatable_relocs(
Symbol_table*,
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;
+ typedef typename Scan_relocatable_reloc::Reltype Reltype;
+ const int reloc_size = Scan_relocatable_reloc::reloc_size;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
Scan_relocatable_reloc scan;
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);
+ const unsigned int r_sym = Scan_relocatable_reloc::get_r_sym(&reloc);
+ const unsigned int r_type =
+ Scan_relocatable_reloc::get_r_type(&reloc);
if (r_sym >= local_symbol_count)
strategy = scan.global_strategy(r_type, object, r_sym);
}
}
-// Relocate relocs during a relocatable link. This is a default
-// definition which should work for most targets.
+// Relocate relocs. Called for a relocatable link, and for --emit-relocs.
+// This is a default definition which should work for most targets.
-template<int size, bool big_endian, int sh_type>
+template<int size, bool big_endian, typename Classify_reloc>
void
-relocate_for_relocatable(
+relocate_relocs(
const Relocate_info<size, big_endian>* relinfo,
const unsigned char* prelocs,
size_t reloc_count,
Output_section* output_section,
- typename elfcpp::Elf_types<size>::Elf_Addr offset_in_output_section,
- const Relocatable_relocs* rr,
+ typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr view_address,
section_size_type view_size,
section_size_type reloc_view_size)
{
typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
- 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;
+ typedef typename Classify_reloc::Reltype Reltype;
+ typedef typename Classify_reloc::Reltype_write Reltype_write;
+ const int reloc_size = Classify_reloc::reloc_size;
const Address invalid_address = static_cast<Address>(0) - 1;
Sized_relobj_file<size, big_endian>* const object = relinfo->object;
unsigned char* pwrite = reloc_view;
+ const bool relocatable = parameters->options().relocatable();
+
for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size)
{
- Relocatable_relocs::Reloc_strategy strategy = rr->strategy(i);
+ Relocatable_relocs::Reloc_strategy strategy = relinfo->rr->strategy(i);
if (strategy == Relocatable_relocs::RELOC_DISCARD)
continue;
// Target wants to handle this relocation.
Sized_target<size, big_endian>* target =
parameters->sized_target<size, big_endian>();
- target->relocate_special_relocatable(relinfo, sh_type, prelocs,
- i, output_section,
+ target->relocate_special_relocatable(relinfo, Classify_reloc::sh_type,
+ prelocs, i, output_section,
offset_in_output_section,
view, view_address,
view_size, pwrite);
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);
+ const unsigned int r_sym = Classify_reloc::get_r_sym(&reloc);
// Get the new symbol index.
+ Output_section* os = NULL;
unsigned int new_symndx;
if (r_sym < local_count)
{
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_2:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4:
case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_8:
+ case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
{
// We are adjusting a section symbol. We need to find
// the symbol table index of the section symbol for
unsigned int shndx =
object->local_symbol_input_shndx(r_sym, &is_ordinary);
gold_assert(is_ordinary);
- Output_section* os = object->output_section(shndx);
+ os = object->output_section(shndx);
gold_assert(os != NULL);
gold_assert(os->needs_symtab_index());
new_symndx = os->symtab_index();
// In an object file, r_offset is an offset within the section.
// In an executable or dynamic object, generated by
// --emit-relocs, r_offset is an absolute address.
- if (!parameters->options().relocatable())
+ if (!relocatable)
{
new_offset += view_address;
if (offset_in_output_section != invalid_address)
}
reloc_write.put_r_offset(new_offset);
- reloc_write.put_r_info(elfcpp::elf_r_info<size>(new_symndx, r_type));
+ Classify_reloc::put_r_info(&reloc_write, &reloc, new_symndx);
// 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);
+ if (Classify_reloc::sh_type == elfcpp::SHT_RELA)
+ Classify_reloc::put_r_addend(&reloc_write,
+ Classify_reloc::get_r_addend(&reloc));
}
else
{
{
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);
+ typename elfcpp::Elf_types<size>::Elf_Swxword addend
+ = Classify_reloc::get_r_addend(&reloc);
addend = psymval->value(object, addend);
- Reloc_types<sh_type, size, big_endian>::
- set_reloc_addend(&reloc_write, addend);
+ // In a relocatable link, the symbol value is relative to
+ // the start of the output section. For a non-relocatable
+ // link, we need to adjust the addend.
+ if (!relocatable)
+ {
+ gold_assert(os != NULL);
+ addend -= os->address();
+ }
+ Classify_reloc::put_r_addend(&reloc_write, addend);
}
break;
psymval);
break;
+ case Relocatable_relocs::RELOC_ADJUST_FOR_SECTION_4_UNALIGNED:
+ Relocate_functions<size, big_endian>::rel32_unaligned(padd,
+ object,
+ psymval);
+ break;
+
default:
gold_unreachable();
}