#include "target-select.h"
#include "tls.h"
#include "freebsd.h"
+#include "gc.h"
namespace
{
Target_i386()
: Target_freebsd<32, false>(&i386_info),
- got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
- copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
+ got_(NULL), plt_(NULL), got_plt_(NULL), global_offset_table_(NULL),
+ rel_dyn_(NULL), copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
{ }
+ inline bool
+ can_check_for_function_pointers() const
+ { return true; }
+
// Process the relocations to determine unreferenced sections for
// garbage collection.
void
- gc_process_relocs(const General_options& options,
- Symbol_table* symtab,
+ gc_process_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
// Scan the relocations to look for symbol adjustments.
void
- scan_relocs(const General_options& options,
- Symbol_table* symtab,
+ scan_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
// Finalize the sections.
void
- do_finalize_sections(Layout*);
+ do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
// Return the value to use for a dynamic which requires special
// treatment.
bool needs_special_offset_handling,
unsigned char* view,
elfcpp::Elf_types<32>::Elf_Addr view_address,
- section_size_type view_size);
+ section_size_type view_size,
+ const Reloc_symbol_changes*);
// Scan the relocs during a relocatable link.
void
- scan_relocatable_relocs(const General_options& options,
- Symbol_table* symtab,
+ scan_relocatable_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
return Target::do_is_local_label_name(name);
}
+ // Return whether SYM is call to a non-split function.
+ bool
+ do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
+
+ // Adjust -fstack-split code which calls non-stack-split code.
+ void
+ do_calls_non_split(Relobj* object, unsigned int shndx,
+ section_offset_type fnoffset, section_size_type fnsize,
+ unsigned char* view, section_size_type view_size,
+ std::string* from, std::string* to) const;
+
// Return the size of the GOT section.
section_size_type
got_size()
struct Scan
{
inline void
- local(const General_options& options, Symbol_table* symtab,
- Layout* layout, Target_i386* target,
+ local(Symbol_table* symtab, Layout* layout, Target_i386* target,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Sym<32, false>& lsym);
inline void
- global(const General_options& options, Symbol_table* symtab,
- Layout* layout, Target_i386* target,
+ global(Symbol_table* symtab, Layout* layout, Target_i386* target,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
Symbol* gsym);
+ inline bool
+ local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
+ Target_i386* target,
+ Sized_relobj<32, false>* object,
+ unsigned int data_shndx,
+ Output_section* output_section,
+ const elfcpp::Rel<32, false>& reloc,
+ unsigned int r_type,
+ const elfcpp::Sym<32, false>& lsym);
+
+ inline bool
+ global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
+ Target_i386* target,
+ Sized_relobj<32, false>* object,
+ unsigned int data_shndx,
+ Output_section* output_section,
+ const elfcpp::Rel<32, false>& reloc,
+ unsigned int r_type,
+ Symbol* gsym);
+
+ inline bool
+ possible_function_pointer_reloc(unsigned int r_type);
+
static void
unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
public:
Relocate()
: skip_call_tls_get_addr_(false),
- local_dynamic_type_(LOCAL_DYNAMIC_NONE), ldo_addrs_()
+ local_dynamic_type_(LOCAL_DYNAMIC_NONE)
{ }
~Relocate()
unsigned char* view,
section_size_type view_size);
- // Fix up LDO_32 relocations we've already seen.
- void
- fix_up_ldo(const Relocate_info<32, false>*);
-
// We need to keep track of which type of local dynamic relocation
// we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
enum Local_dynamic_type
// The type of local dynamic relocation we have seen in the section
// being relocated, if any.
Local_dynamic_type local_dynamic_type_;
- // A list of LDO_32 offsets, in case we find LDM after LDO_32.
- std::vector<unsigned char*> ldo_addrs_;
};
// A class which returns the size required for a relocation type,
Sized_relobj<32, false>* object);
// Get the PLT section.
- const Output_data_plt_i386*
+ Output_data_plt_i386*
plt_section() const
{
gold_assert(this->plt_ != NULL);
Reloc_section*
rel_dyn_section(Layout*);
+ // Get the section to use for TLS_DESC relocations.
+ Reloc_section*
+ rel_tls_desc_section(Layout*) const;
+
// Add a potential copy relocation.
void
copy_reloc(Symbol_table* symtab, Layout* layout,
Output_data_plt_i386* plt_;
// The GOT PLT section.
Output_data_space* got_plt_;
+ // The _GLOBAL_OFFSET_TABLE_ symbol.
+ Symbol* global_offset_table_;
// The dynamic reloc section.
Reloc_section* rel_dyn_;
// Relocs saved to avoid a COPY reloc.
elfcpp::SHN_UNDEF, // small_common_shndx
elfcpp::SHN_UNDEF, // large_common_shndx
0, // small_common_section_flags
- 0 // large_common_section_flags
+ 0, // large_common_section_flags
+ NULL, // attributes_section
+ NULL // attributes_vendor
};
// Get the GOT section, creating it if necessary.
os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
- this->got_);
- os->set_is_relro();
+ this->got_, false, true, true,
+ false);
- // The old GNU linker creates a .got.plt section. We just
- // create another set of data in the .got section. Note that we
- // always create a PLT if we create a GOT, although the PLT
- // might be empty.
this->got_plt_ = new Output_data_space(4, "** GOT PLT");
- os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
+ os = layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
- this->got_plt_);
- os->set_is_relro();
+ this->got_plt_, false, false, false,
+ true);
// The first three entries are reserved.
this->got_plt_->set_current_data_size(3 * 4);
+ // Those bytes can go into the relro segment.
+ layout->increase_relro(3 * 4);
+
// Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
- symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
- this->got_plt_,
- 0, 0, elfcpp::STT_OBJECT,
- elfcpp::STB_LOCAL,
- elfcpp::STV_HIDDEN, 0,
- false, false);
+ this->global_offset_table_ =
+ symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
+ Symbol_table::PREDEFINED,
+ this->got_plt_,
+ 0, 0, elfcpp::STT_OBJECT,
+ elfcpp::STB_LOCAL,
+ elfcpp::STV_HIDDEN, 0,
+ false, false);
}
return this->got_;
gold_assert(layout != NULL);
this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
- elfcpp::SHF_ALLOC, this->rel_dyn_);
+ elfcpp::SHF_ALLOC, this->rel_dyn_, true,
+ false, false, false);
}
return this->rel_dyn_;
}
rel_plt() const
{ return this->rel_; }
+ // Return where the TLS_DESC relocations should go.
+ Reloc_section*
+ rel_tls_desc(Layout*);
+
protected:
void
do_adjust_output_section(Output_section* os);
// The reloc section.
Reloc_section* rel_;
+ // The TLS_DESC relocations, if necessary. These must follow the
+ // regular PLT relocs.
+ Reloc_section* tls_desc_rel_;
// The .got.plt section.
Output_data_space* got_plt_;
// The number of PLT entries.
Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
Output_data_space* got_plt)
- : Output_section_data(4), got_plt_(got_plt), count_(0)
+ : Output_section_data(4), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0)
{
this->rel_ = new Reloc_section(false);
layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
- elfcpp::SHF_ALLOC, this->rel_);
+ elfcpp::SHF_ALLOC, this->rel_, true,
+ false, false, false);
}
void
// appear in the relocations.
}
+// Return where the TLS_DESC relocations should go, creating it if
+// necessary. These follow the JUMP_SLOT relocations.
+
+Output_data_plt_i386::Reloc_section*
+Output_data_plt_i386::rel_tls_desc(Layout* layout)
+{
+ if (this->tls_desc_rel_ == NULL)
+ {
+ this->tls_desc_rel_ = new Reloc_section(false);
+ layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
+ elfcpp::SHF_ALLOC, this->tls_desc_rel_,
+ true, false, false, false);
+ gold_assert(this->tls_desc_rel_->output_section() ==
+ this->rel_->output_section());
+ }
+ return this->tls_desc_rel_;
+}
+
// The first entry in the PLT for an executable.
unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
- if (parameters->options().shared())
+ if (parameters->options().output_is_position_independent())
memcpy(pov, dyn_first_plt_entry, plt_entry_size);
else
{
{
// Set and adjust the PLT entry itself.
- if (parameters->options().shared())
+ if (parameters->options().output_is_position_independent())
{
memcpy(pov, dyn_plt_entry, plt_entry_size);
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR),
- this->plt_);
+ this->plt_, false, false, false, false);
}
this->plt_->add_entry(gsym);
}
+// Get the section to use for TLS_DESC relocations.
+
+Target_i386::Reloc_section*
+Target_i386::rel_tls_desc_section(Layout* layout) const
+{
+ return this->plt_section()->rel_tls_desc(layout);
+}
+
// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
void
{
bool is_exec = parameters->options().output_is_executable();
symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
+ Symbol_table::PREDEFINED,
tls_segment, 0, 0,
elfcpp::STT_TLS,
elfcpp::STB_LOCAL,
// Scan a relocation for a local symbol.
inline void
-Target_i386::Scan::local(const General_options&,
- Symbol_table* symtab,
+Target_i386::Scan::local(Symbol_table* symtab,
Layout* layout,
Target_i386* target,
Sized_relobj<32, false>* object,
Output_data_got<32, false>* got
= target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
- unsigned int shndx = lsym.get_st_shndx();
- bool is_ordinary;
- shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
- if (!is_ordinary)
- object->error(_("local symbol %u has bad shndx %u"),
- r_sym, shndx);
- else
- got->add_local_pair_with_rel(object, r_sym, shndx,
- GOT_TYPE_TLS_DESC,
- target->rel_dyn_section(layout),
- elfcpp::R_386_TLS_DESC, 0);
+ if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
+ {
+ unsigned int got_offset = got->add_constant(0);
+ // The local symbol value is stored in the second
+ // GOT entry.
+ got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
+ // That set the GOT offset of the local symbol to
+ // point to the second entry, but we want it to
+ // point to the first.
+ object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
+ got_offset);
+ Reloc_section* rt = target->rel_tls_desc_section(layout);
+ rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
+ }
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
object->name().c_str(), r_type, gsym->demangled_name().c_str());
}
+inline bool
+Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
+{
+ switch (r_type)
+ {
+ case elfcpp::R_386_32:
+ case elfcpp::R_386_16:
+ case elfcpp::R_386_8:
+ case elfcpp::R_386_GOTOFF:
+ case elfcpp::R_386_GOT32:
+ {
+ return true;
+ }
+ default:
+ return false;
+ }
+ return false;
+}
+
+inline bool
+Target_i386::Scan::local_reloc_may_be_function_pointer(
+ Symbol_table* ,
+ Layout* ,
+ Target_i386* ,
+ Sized_relobj<32, false>* ,
+ unsigned int ,
+ Output_section* ,
+ const elfcpp::Rel<32, false>& ,
+ unsigned int r_type,
+ const elfcpp::Sym<32, false>&)
+{
+ return possible_function_pointer_reloc(r_type);
+}
+
+inline bool
+Target_i386::Scan::global_reloc_may_be_function_pointer(
+ Symbol_table* ,
+ Layout* ,
+ Target_i386* ,
+ Sized_relobj<32, false>* ,
+ unsigned int ,
+ Output_section* ,
+ const elfcpp::Rel<32, false>& ,
+ unsigned int r_type,
+ Symbol*)
+{
+ return possible_function_pointer_reloc(r_type);
+}
+
// Scan a relocation for a global symbol.
inline void
-Target_i386::Scan::global(const General_options&,
- Symbol_table* symtab,
+Target_i386::Scan::global(Symbol_table* symtab,
Layout* layout,
Target_i386* target,
Sized_relobj<32, false>* object,
}
// Make a dynamic relocation if necessary.
int flags = Symbol::NON_PIC_REF;
- if (gsym->type() == elfcpp::STT_FUNC)
+ if (gsym->is_func())
flags |= Symbol::FUNCTION_CALL;
if (gsym->needs_dynamic_reloc(flags))
{
// Create a double GOT entry with an R_386_TLS_DESC reloc.
Output_data_got<32, false>* got
= target->got_section(symtab, layout);
- got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC,
- target->rel_dyn_section(layout),
+ Reloc_section* rt = target->rel_tls_desc_section(layout);
+ got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
elfcpp::R_386_TLS_DESC, 0);
}
else if (optimized_type == tls::TLSOPT_TO_IE)
// Process relocations for gc.
void
-Target_i386::gc_process_relocs(const General_options& options,
- Symbol_table* symtab,
+Target_i386::gc_process_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
{
gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
Target_i386::Scan>(
- options,
symtab,
layout,
this,
// Scan relocations for a section.
void
-Target_i386::scan_relocs(const General_options& options,
- Symbol_table* symtab,
+Target_i386::scan_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
Target_i386::Scan>(
- options,
symtab,
layout,
this,
// Finalize the sections.
void
-Target_i386::do_finalize_sections(Layout* layout)
+Target_i386::do_finalize_sections(
+ Layout* layout,
+ const Input_objects*,
+ Symbol_table* symtab)
{
- // Fill in some more dynamic tags.
- Output_data_dynamic* const odyn = layout->dynamic_data();
- if (odyn != NULL)
- {
- if (this->got_plt_ != NULL)
- odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
-
- if (this->plt_ != NULL)
- {
- const Output_data* od = this->plt_->rel_plt();
- odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
- odyn->add_section_address(elfcpp::DT_JMPREL, od);
- odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
- }
-
- if (this->rel_dyn_ != NULL)
- {
- const Output_data* od = this->rel_dyn_;
- odyn->add_section_address(elfcpp::DT_REL, od);
- odyn->add_section_size(elfcpp::DT_RELSZ, od);
- odyn->add_constant(elfcpp::DT_RELENT,
- elfcpp::Elf_sizes<32>::rel_size);
- }
-
- if (!parameters->options().shared())
- {
- // The value of the DT_DEBUG tag is filled in by the dynamic
- // linker at run time, and used by the debugger.
- odyn->add_constant(elfcpp::DT_DEBUG, 0);
- }
- }
+ const Reloc_section* rel_plt = (this->plt_ == NULL
+ ? NULL
+ : this->plt_->rel_plt());
+ layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
+ this->rel_dyn_, true, false);
// Emit any relocs we saved in an attempt to avoid generating COPY
// relocs.
if (this->copy_relocs_.any_saved_relocs())
this->copy_relocs_.emit(this->rel_dyn_section(layout));
+
+ // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
+ // the .got.plt section.
+ Symbol* sym = this->global_offset_table_;
+ if (sym != NULL)
+ {
+ uint32_t data_size = this->got_plt_->current_data_size();
+ symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
+ }
}
// Return whether a direct absolute static relocation needs to be applied.
case elfcpp::R_386_PC32:
{
int ref_flags = Symbol::NON_PIC_REF;
- if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
+ if (gsym != NULL && gsym->is_func())
ref_flags |= Symbol::FUNCTION_CALL;
if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
case elfcpp::R_386_PC16:
{
int ref_flags = Symbol::NON_PIC_REF;
- if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
+ if (gsym != NULL && gsym->is_func())
ref_flags |= Symbol::FUNCTION_CALL;
if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
case elfcpp::R_386_PC8:
{
int ref_flags = Symbol::NON_PIC_REF;
- if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
+ if (gsym != NULL && gsym->is_func())
ref_flags |= Symbol::FUNCTION_CALL;
if (should_apply_static_reloc(gsym, ref_flags, false,
output_section))
elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
- const bool is_final =
- (gsym == NULL
- ? !parameters->options().output_is_position_independent()
- : gsym->final_value_is_known());
+ const bool is_final = (gsym == NULL
+ ? !parameters->options().shared()
+ : gsym->final_value_is_known());
const tls::Tls_optimization optimized_type
= Target_i386::optimize_tls_reloc(is_final, r_type);
switch (r_type)
case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
case elfcpp::R_386_TLS_DESC_CALL:
- if (this->local_dynamic_type_ == LOCAL_DYNAMIC_NONE)
- this->fix_up_ldo(relinfo);
this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
if (optimized_type == tls::TLSOPT_TO_LE)
{
"TLS relocations"));
break;
}
- else if (this->local_dynamic_type_ == LOCAL_DYNAMIC_NONE)
- this->fix_up_ldo(relinfo);
this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
if (optimized_type == tls::TLSOPT_TO_LE)
{
break;
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
- // This reloc can appear in debugging sections, in which case we
- // won't see the TLS_LDM reloc. The local_dynamic_type field
- // tells us this.
if (optimized_type == tls::TLSOPT_TO_LE)
{
- if (this->local_dynamic_type_ != LOCAL_DYNAMIC_NONE)
+ // This reloc can appear in debugging sections, in which
+ // case we must not convert to local-exec. We decide what
+ // to do based on whether the section is marked as
+ // containing executable code. That is what the GNU linker
+ // does as well.
+ elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
+ if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
{
gold_assert(tls_segment != NULL);
value -= tls_segment->memsz();
}
- else
- {
- // We may see the LDM later.
- this->ldo_addrs_.push_back(view);
- }
}
Relocate_functions<32, false>::rel32(view, value);
break;
Relocate_functions<32, false>::rel32(view, value);
}
-// If we see an LDM reloc after we handled any LDO_32 relocs, fix up
-// the LDO_32 relocs.
-
-void
-Target_i386::Relocate::fix_up_ldo(const Relocate_info<32, false>* relinfo)
-{
- if (this->ldo_addrs_.empty())
- return;
- Output_segment* tls_segment = relinfo->layout->tls_segment();
- gold_assert(tls_segment != NULL);
- elfcpp::Elf_types<32>::Elf_Addr value = - tls_segment->memsz();
- for (std::vector<unsigned char*>::const_iterator p = this->ldo_addrs_.begin();
- p != this->ldo_addrs_.end();
- ++p)
- Relocate_functions<32, false>::rel32(*p, value);
- this->ldo_addrs_.clear();
-}
-
// Relocate section data.
void
bool needs_special_offset_handling,
unsigned char* view,
elfcpp::Elf_types<32>::Elf_Addr address,
- section_size_type view_size)
+ section_size_type view_size,
+ const Reloc_symbol_changes* reloc_symbol_changes)
{
gold_assert(sh_type == elfcpp::SHT_REL);
needs_special_offset_handling,
view,
address,
- view_size);
+ view_size,
+ reloc_symbol_changes);
}
// Return the size of a relocation while scanning during a relocatable
// Scan the relocs during a relocatable link.
void
-Target_i386::scan_relocatable_relocs(const General_options& options,
- Symbol_table* symtab,
+Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
Layout* layout,
Sized_relobj<32, false>* object,
unsigned int data_shndx,
gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
Scan_relocatable_relocs>(
- options,
symtab,
layout,
object,
return std::string(nops[length], length);
}
+// Return whether SYM should be treated as a call to a non-split
+// function. We don't want that to be true of a call to a
+// get_pc_thunk function.
+
+bool
+Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
+{
+ return (sym->type() == elfcpp::STT_FUNC
+ && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
+}
+
+// FNOFFSET in section SHNDX in OBJECT is the start of a function
+// compiled with -fstack-split. The function calls non-stack-split
+// code. We have to change the function so that it always ensures
+// that it has enough stack space to run some random function.
+
+void
+Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
+ section_offset_type fnoffset,
+ section_size_type fnsize,
+ unsigned char* view,
+ section_size_type view_size,
+ std::string* from,
+ std::string* to) const
+{
+ // The function starts with a comparison of the stack pointer and a
+ // field in the TCB. This is followed by a jump.
+
+ // cmp %gs:NN,%esp
+ if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
+ && fnsize > 7)
+ {
+ // We will call __morestack if the carry flag is set after this
+ // comparison. We turn the comparison into an stc instruction
+ // and some nops.
+ view[fnoffset] = '\xf9';
+ this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
+ }
+ // lea NN(%esp),%ecx
+ // lea NN(%esp),%edx
+ else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
+ || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
+ && fnsize > 7)
+ {
+ // This is loading an offset from the stack pointer for a
+ // comparison. The offset is negative, so we decrease the
+ // offset by the amount of space we need for the stack. This
+ // means we will avoid calling __morestack if there happens to
+ // be plenty of space on the stack already.
+ unsigned char* pval = view + fnoffset + 3;
+ uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
+ val -= parameters->options().split_stack_adjust_size();
+ elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
+ }
+ else
+ {
+ if (!object->has_no_split_stack())
+ object->error(_("failed to match split-stack sequence at "
+ "section %u offset %0zx"),
+ shndx, static_cast<size_t>(fnoffset));
+ return;
+ }
+
+ // We have to change the function so that it calls
+ // __morestack_non_split instead of __morestack. The former will
+ // allocate additional stack space.
+ *from = "__morestack";
+ *to = "__morestack_non_split";
+}
+
// The selector for i386 object files.
class Target_selector_i386 : public Target_selector_freebsd