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From Cary Coutant: More support for -shared, including fixes to GOT

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handling.
This commit is contained in:
Ian Lance Taylor 2007-11-01 00:19:30 +00:00
parent 823963270f
commit 96f2030e25
3 changed files with 205 additions and 79 deletions
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129
gold/i386.cc
View File

@ -97,6 +97,14 @@ class Target_i386 : public Sized_target<32, false>
std::string
do_code_fill(off_t length);
// Return the size of the GOT section.
off_t
got_size()
{
gold_assert(this->got_ != NULL);
return this->got_->data_size();
}
private:
// The class which scans relocations.
struct Scan
@ -215,6 +223,14 @@ class Target_i386 : public Sized_target<32, false>
Output_data_got<32, false>*
got_section(Symbol_table*, Layout*);
// Get the GOT PLT section.
Output_data_space*
got_plt_section() const
{
gold_assert(this->got_plt_ != NULL);
return this->got_plt_;
}
// Create a PLT entry for a global symbol.
void
make_plt_entry(Symbol_table*, Layout*, Symbol*);
@ -756,6 +772,9 @@ Target_i386::Scan::local(const General_options&,
// relocate it easily.
if (parameters->output_is_position_independent())
{
// FIXME: R_386_RELATIVE only works for a 32-bit relocation.
gold_assert(r_type != elfcpp::R_386_16 && r_type != elfcpp::R_386_8);
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE, data_shndx,
reloc.get_r_offset());
@ -924,42 +943,73 @@ Target_i386::Scan::global(const General_options& options,
case elfcpp::R_386_PC16:
case elfcpp::R_386_8:
case elfcpp::R_386_PC8:
if (gsym->is_from_dynobj()
|| (parameters->output_is_shared()
&& gsym->is_preemptible()))
{
// (a) This symbol is defined in a dynamic object. If it is a
// function, we make a PLT entry. Otherwise we need to
// either generate a COPY reloc or copy this reloc.
// (b) We are building a shared object and this symbol is
// preemptible. If it is a function, we make a PLT entry.
// Otherwise, we copy the reloc. We do not make COPY relocs
// in shared objects.
if (gsym->type() == elfcpp::STT_FUNC)
{
target->make_plt_entry(symtab, layout, gsym);
{
bool is_pcrel = (r_type == elfcpp::R_386_PC32
|| r_type == elfcpp::R_386_PC16
|| r_type == elfcpp::R_386_PC8);
// If this is not a PC relative reference, then we may
// be taking the address of the function. In that case
// we need to set the entry in the dynamic symbol table
// to the address of the PLT entry.
if (r_type != elfcpp::R_386_PC32
&& r_type != elfcpp::R_386_PC16
&& r_type != elfcpp::R_386_PC8
&& gsym->is_from_dynobj())
gsym->set_needs_dynsym_value();
}
else if (parameters->output_is_shared())
{
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
rel_dyn->add_global(gsym, r_type, object, data_shndx,
reloc.get_r_offset());
}
else
target->copy_reloc(&options, symtab, layout, object, data_shndx,
gsym, reloc);
}
if (gsym->is_from_dynobj()
|| (parameters->output_is_shared()
&& gsym->is_preemptible()))
{
// (a) This symbol is defined in a dynamic object. If it is a
// function, we make a PLT entry. Otherwise we need to
// either generate a COPY reloc or copy this reloc.
// (b) We are building a shared object and this symbol is
// preemptible. If it is a function, we make a PLT entry.
// Otherwise, we copy the reloc.
if (gsym->type() == elfcpp::STT_FUNC)
{
target->make_plt_entry(symtab, layout, gsym);
// If this is not a PC relative reference, then we may
// be taking the address of the function. In that case
// we need to set the entry in the dynamic symbol table
// to the address of the PLT entry. We will also need to
// create a dynamic relocation.
if (!is_pcrel)
{
if (gsym->is_from_dynobj())
gsym->set_needs_dynsym_value();
if (parameters->output_is_position_independent())
{
// FIXME: If this is an 8-bit or 16-bit
// relocation, R_386_RELATIVE won't work.
gold_assert(r_type != elfcpp::R_386_16
&& r_type != elfcpp::R_386_8);
Reloc_section* rel_dyn =
target->rel_dyn_section(layout);
rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE,
data_shndx, reloc.get_r_offset());
}
}
}
else if (parameters->output_is_shared())
{
// We do not make COPY relocs in shared objects.
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
rel_dyn->add_global(gsym, r_type, object, data_shndx,
reloc.get_r_offset());
}
else
target->copy_reloc(&options, symtab, layout, object, data_shndx,
gsym, reloc);
}
else if (!is_pcrel && parameters->output_is_position_independent())
{
// FIXME: If this is an 8-bit or 16-bit relocation,
// R_386_RELATIVE won't work.
gold_assert(r_type != elfcpp::R_386_16
&& r_type != elfcpp::R_386_8);
// This is not a PC-relative reference, so we need to generate
// a dynamic relocation.
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
rel_dyn->add_local(object, 0, elfcpp::R_386_RELATIVE, data_shndx,
reloc.get_r_offset());
}
}
break;
case elfcpp::R_386_GOT32:
@ -1222,6 +1272,9 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
const Sized_relobj<32, false>* object = relinfo->object;
// Get the GOT offset if needed.
// The GOT pointer points to the end of the GOT section.
// We need to subtract the size of the GOT section to get
// the actual offset to use in the relocation.
bool have_got_offset = false;
unsigned int got_offset = 0;
switch (r_type)
@ -1230,12 +1283,12 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
if (gsym != NULL)
{
gold_assert(gsym->has_got_offset());
got_offset = gsym->got_offset();
got_offset = gsym->got_offset() - target->got_size();
}
else
{
unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
got_offset = object->local_got_offset(r_sym);
got_offset = object->local_got_offset(r_sym) - target->got_size();
}
have_got_offset = true;
break;
@ -1291,7 +1344,7 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
{
elfcpp::Elf_types<32>::Elf_Addr value;
value = (psymval->value(object, 0)
- target->got_section(NULL, NULL)->address());
- target->got_plt_section()->address());
Relocate_functions<32, false>::rel32(view, value);
}
break;
@ -1299,7 +1352,7 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
case elfcpp::R_386_GOTPC:
{
elfcpp::Elf_types<32>::Elf_Addr value;
value = target->got_section(NULL, NULL)->address();
value = target->got_plt_section()->address();
Relocate_functions<32, false>::pcrel32(view, value, address);
}
break;

3
gold/layout.cc
View File

@ -591,7 +591,8 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
// Create the .interp section to hold the name of the
// interpreter, and put it in a PT_INTERP segment.
this->create_interp(target);
if (!parameters->output_is_shared())
this->create_interp(target);
// Finish the .dynamic section to hold the dynamic data, and put
// it in a PT_DYNAMIC segment.

152
gold/x86_64.cc
View File

@ -110,6 +110,14 @@ class Target_x86_64 : public Sized_target<64, false>
std::string
do_code_fill(off_t length);
// Return the size of the GOT section.
off_t
got_size()
{
gold_assert(this->got_ != NULL);
return this->got_->data_size();
}
private:
// The class which scans relocations.
struct Scan
@ -215,6 +223,14 @@ class Target_x86_64 : public Sized_target<64, false>
Output_data_got<64, false>*
got_section(Symbol_table*, Layout*);
// Get the GOT PLT section.
Output_data_space*
got_plt_section() const
{
gold_assert(this->got_plt_ != NULL);
return this->got_plt_;
}
// Create a PLT entry for a global symbol.
void
make_plt_entry(Symbol_table*, Layout*, Symbol*);
@ -719,9 +735,21 @@ Target_x86_64::Scan::local(const General_options&,
case elfcpp::R_X86_64_32S:
case elfcpp::R_X86_64_16:
case elfcpp::R_X86_64_8:
// FIXME: If we are generating a shared object we need to copy
// this relocation into the object.
gold_assert(!parameters->output_is_shared());
// If building a shared library (or a position-independent
// executable), we need to create a dynamic relocation for
// this location. The relocation applied at link time will
// apply the link-time value, so we flag the location with
// an R_386_RELATIVE relocation so the dynamic loader can
// relocate it easily.
if (parameters->output_is_position_independent())
{
// FIXME: R_X86_64_RELATIVE assumes a 64-bit relocation.
gold_assert(r_type == elfcpp::R_X86_64_64);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_local(object, 0, elfcpp::R_X86_64_RELATIVE,
data_shndx, reloc.get_r_offset(), 0);
}
break;
case elfcpp::R_X86_64_PC64:
@ -758,8 +786,11 @@ Target_x86_64::Scan::local(const General_options&,
{
// If we are generating a shared object, we need to add a
// dynamic RELATIVE relocation for this symbol.
if (parameters->output_is_shared())
if (parameters->output_is_position_independent())
{
// FIXME: R_X86_64_RELATIVE assumes a 64-bit relocation.
gold_assert(r_type != elfcpp::R_X86_64_GOT32);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_local(object, 0, elfcpp::R_X86_64_RELATIVE,
data_shndx, reloc.get_r_offset(), 0);
@ -884,36 +915,63 @@ Target_x86_64::Scan::global(const General_options& options,
case elfcpp::R_X86_64_PC16:
case elfcpp::R_X86_64_8:
case elfcpp::R_X86_64_PC8:
// FIXME: If we are generating a shared object we may need to
// copy this relocation into the object. If this symbol is
// defined in a shared object, we may need to copy this
// relocation in order to avoid a COPY relocation.
gold_assert(!parameters->output_is_shared());
{
bool is_pcrel = (r_type == elfcpp::R_X86_64_PC64
|| r_type == elfcpp::R_X86_64_PC32
|| r_type == elfcpp::R_X86_64_PC16
|| r_type == elfcpp::R_X86_64_PC8);
if (gsym->is_from_dynobj())
{
// This symbol is defined in a dynamic object. If it is a
// function, we make a PLT entry. Otherwise we need to
// either generate a COPY reloc or copy this reloc.
if (gsym->type() == elfcpp::STT_FUNC)
{
target->make_plt_entry(symtab, layout, gsym);
if (gsym->is_from_dynobj()
|| (parameters->output_is_shared()
&& gsym->is_preemptible()))
{
// (a) This symbol is defined in a dynamic object. If it is a
// function, we make a PLT entry. Otherwise we need to
// either generate a COPY reloc or copy this reloc.
// (b) We are building a shared object and this symbol is
// preemptible. If it is a function, we make a PLT entry.
// Otherwise, we copy the reloc.
if (gsym->type() == elfcpp::STT_FUNC)
{
target->make_plt_entry(symtab, layout, gsym);
// If this is not a PC relative reference, then we may
// be taking the address of the function. In that case
// we need to set the entry in the dynamic symbol table
// to the address of the PLT entry.
if (r_type != elfcpp::R_X86_64_PC64
&& r_type != elfcpp::R_X86_64_PC32
&& r_type != elfcpp::R_X86_64_PC16
&& r_type != elfcpp::R_X86_64_PC8)
gsym->set_needs_dynsym_value();
}
else
target->copy_reloc(&options, symtab, layout, object, data_shndx,
gsym, reloc);
// If this is not a PC relative reference, then we may
// be taking the address of the function. In that case
// we need to set the entry in the dynamic symbol table
// to the address of the PLT entry. We will also need to
// create a dynamic relocation.
if (!is_pcrel)
{
if (gsym->is_from_dynobj())
gsym->set_needs_dynsym_value();
if (parameters->output_is_position_independent())
{
// FIXME: R_X86_64_RELATIVE assumes a 64-bit
// relocation.
gold_assert(r_type == elfcpp::R_X86_64_64);
Reloc_section* rela_dyn =
target->rela_dyn_section(layout);
rela_dyn->add_local(object, 0,
elfcpp::R_X86_64_RELATIVE,
data_shndx,
reloc.get_r_offset(), 0);
}
}
}
else if (parameters->output_is_shared())
{
// We do not make COPY relocs in shared objects.
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_global(gsym, r_type, object, data_shndx,
reloc.get_r_offset(),
reloc.get_r_addend());
}
else
target->copy_reloc(&options, symtab, layout, object, data_shndx,
gsym, reloc);
}
}
break;
case elfcpp::R_X86_64_GOT64:
@ -948,6 +1006,13 @@ Target_x86_64::Scan::global(const General_options& options,
// Otherwise we need a PLT entry.
if (gsym->final_value_is_known())
break;
// If building a shared library, we can also skip the PLT entry
// if the symbol is defined in the output file and is protected
// or hidden.
if (gsym->is_defined()
&& !gsym->is_from_dynobj()
&& !gsym->is_preemptible())
break;
target->make_plt_entry(symtab, layout, gsym);
break;
@ -1156,7 +1221,11 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
// Pick the value to use for symbols defined in shared objects.
Symbol_value<64> symval;
if (gsym != NULL && gsym->is_from_dynobj() && gsym->has_plt_offset())
if (gsym != NULL
&& (gsym->is_from_dynobj()
|| (parameters->output_is_shared()
&& gsym->is_preemptible()))
&& gsym->has_plt_offset())
{
symval.set_output_value(target->plt_section()->address()
+ gsym->plt_offset());
@ -1167,6 +1236,9 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
const elfcpp::Elf_Xword addend = rela.get_r_addend();
// Get the GOT offset if needed.
// The GOT pointer points to the end of the GOT section.
// We need to subtract the size of the GOT section to get
// the actual offset to use in the relocation.
bool have_got_offset = false;
unsigned int got_offset = 0;
switch (r_type)
@ -1179,12 +1251,12 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
if (gsym != NULL)
{
gold_assert(gsym->has_got_offset());
got_offset = gsym->got_offset();
got_offset = gsym->got_offset() - target->got_size();
}
else
{
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
got_offset = object->local_got_offset(r_sym);
got_offset = object->local_got_offset(r_sym) - target->got_size();
}
have_got_offset = true;
break;
@ -1278,7 +1350,7 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
{
gold_assert(gsym);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_section(NULL, NULL)->address();
value = target->got_plt_section()->address();
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
}
break;
@ -1295,7 +1367,7 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
{
gold_assert(gsym);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_section(NULL, NULL)->address();
value = target->got_plt_section()->address();
Relocate_functions<64, false>::pcrela64(view, value, addend, address);
}
break;
@ -1304,7 +1376,7 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
{
elfcpp::Elf_types<64>::Elf_Addr value;
value = (psymval->value(object, 0)
- target->got_section(NULL, NULL)->address());
- target->got_plt_section()->address());
Relocate_functions<64, false>::rela64(view, value, addend);
}
break;
@ -1313,7 +1385,7 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
{
gold_assert(have_got_offset);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_section(NULL, NULL)->address() + got_offset;
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
}
break;
@ -1322,7 +1394,7 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
{
gold_assert(have_got_offset);
elfcpp::Elf_types<64>::Elf_Addr value;
value = target->got_section(NULL, NULL)->address() + got_offset;
value = target->got_plt_section()->address() + got_offset;
Relocate_functions<64, false>::pcrela64(view, value, addend, address);
}
break;
@ -1389,7 +1461,7 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
const bool is_final = (gsym == NULL
? !parameters->output_is_shared()
? !parameters->output_is_position_independent()
: gsym->final_value_is_known());
const tls::Tls_optimization optimized_type
= Target_x86_64::optimize_tls_reloc(is_final, r_type);