PR21503, Gold doesn't create linker stub symbols on ppc64
PR 21503 * options.h: Add --emit-stub-syms option. * powerpc.cc (object_id): New. (Powerpc_relobj): Add uniq_ and accessor. Sort variables for better packing. (Powerpc_dynobj): Sort variables for better packing. (Target_powerpc::define_local): New function. (Target_powerpc::group_sections): Pass stub table size to Stub_table constructor. (Target_powerpc::do_relax): Define stub and glink symbols. (Stub_table): Add uniq_ variable, and id param to constructor. (Stub_table::Plt_stub_ent): Add indx_ variable. (Stub_table::Branch_stub_entries): Move typedef earlier. (Stub_table::branch_stub_size): Replace "to" parameter with a Branch_stub_entries iterator. (Stub_table::add_long_branch_entry): Adjust to suit. (Stub_table::add_plt_call_entry): Set indx_. (Stub_table::define_stub_syms): New function.
This commit is contained in:
Alan Modra
parent
6e3f3473e2
commit
590b87ffa3
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@ -1,3 +1,24 @@
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2017-05-23 Alan Modra <amodra@gmail.com>
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PR 21503
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* options.h: Add --emit-stub-syms option.
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* powerpc.cc (object_id): New.
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(Powerpc_relobj): Add uniq_ and accessor. Sort variables for
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better packing.
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(Powerpc_dynobj): Sort variables for better packing.
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(Target_powerpc::define_local): New function.
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(Target_powerpc::group_sections): Pass stub table size to
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Stub_table constructor.
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(Target_powerpc::do_relax): Define stub and glink symbols.
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(Stub_table): Add uniq_ variable, and id param to constructor.
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(Stub_table::Plt_stub_ent): Add indx_ variable.
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(Stub_table::Branch_stub_entries): Move typedef earlier.
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(Stub_table::branch_stub_size): Replace "to" parameter with a
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Branch_stub_entries iterator.
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(Stub_table::add_long_branch_entry): Adjust to suit.
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(Stub_table::add_plt_call_entry): Set indx_.
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(Stub_table::define_stub_syms): New function.
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2017-05-15 Eric Christopher <echristo@gmail.com>
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* layout.cc (Layout::segment_precedes): Add a case for testing
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@ -814,6 +814,10 @@ class General_options
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// e
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DEFINE_bool(emit_stub_syms, options::TWO_DASHES, '\0', true,
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N_("(PowerPC only) Label linker stubs with a symbol"),
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N_("(PowerPC only) Do not label linker stubs with a symbol"));
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DEFINE_string(entry, options::TWO_DASHES, 'e', NULL,
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N_("Set program start address"), N_("ADDRESS"));
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192
gold/powerpc.cc
192
gold/powerpc.cc
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@ -81,6 +81,9 @@ struct Stub_table_owner
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inline bool
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is_branch_reloc(unsigned int r_type);
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// Counter incremented on every Powerpc_relobj constructed.
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static uint32_t object_id = 0;
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template<int size, bool big_endian>
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class Powerpc_relobj : public Sized_relobj_file<size, big_endian>
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{
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@ -92,10 +95,10 @@ public:
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Powerpc_relobj(const std::string& name, Input_file* input_file, off_t offset,
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const typename elfcpp::Ehdr<size, big_endian>& ehdr)
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: Sized_relobj_file<size, big_endian>(name, input_file, offset, ehdr),
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special_(0), relatoc_(0), toc_(0), no_toc_opt_(),
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has_small_toc_reloc_(false), opd_valid_(false), opd_ent_(),
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access_from_map_(), has14_(), stub_table_index_(),
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e_flags_(ehdr.get_e_flags()), st_other_()
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uniq_(object_id++), special_(0), relatoc_(0), toc_(0),
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has_small_toc_reloc_(false), opd_valid_(false),
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e_flags_(ehdr.get_e_flags()), no_toc_opt_(), opd_ent_(),
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access_from_map_(), has14_(), stub_table_index_(), st_other_()
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{
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this->set_abiversion(0);
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}
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@ -357,6 +360,10 @@ public:
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this->stub_table_index_.clear();
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}
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uint32_t
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uniq() const
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{ return this->uniq_; }
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int
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abiversion() const
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{ return this->e_flags_ & elfcpp::EF_PPC64_ABI; }
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@ -396,6 +403,9 @@ private:
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opd_ent_ndx(size_t off) const
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{ return off >> 4;}
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// Per object unique identifier
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uint32_t uniq_;
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// For 32-bit the .got2 section shdnx, for 64-bit the .opd section shndx.
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unsigned int special_;
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@ -403,10 +413,6 @@ private:
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unsigned int relatoc_;
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unsigned int toc_;
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// For 64-bit, an array with one entry per 64-bit word in the .toc
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// section, set if accesses using that word cannot be optimised.
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std::vector<bool> no_toc_opt_;
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// For 64-bit, whether this object uses small model relocs to access
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// the toc.
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bool has_small_toc_reloc_;
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@ -418,6 +424,13 @@ private:
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// access_from_map_.
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bool opd_valid_;
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// Header e_flags
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elfcpp::Elf_Word e_flags_;
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// For 64-bit, an array with one entry per 64-bit word in the .toc
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// section, set if accesses using that word cannot be optimised.
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std::vector<bool> no_toc_opt_;
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// The first 8-byte word of an OPD entry gives the address of the
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// entry point of the function. Relocatable object files have a
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// relocation on this word. The following vector records the
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@ -435,9 +448,6 @@ private:
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// The stub table to use for a given input section.
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std::vector<unsigned int> stub_table_index_;
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// Header e_flags
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elfcpp::Elf_Word e_flags_;
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// ELF st_other field for local symbols.
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std::vector<unsigned char> st_other_;
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};
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@ -451,7 +461,7 @@ public:
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Powerpc_dynobj(const std::string& name, Input_file* input_file, off_t offset,
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const typename elfcpp::Ehdr<size, big_endian>& ehdr)
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: Sized_dynobj<size, big_endian>(name, input_file, offset, ehdr),
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opd_shndx_(0), opd_ent_(), e_flags_(ehdr.get_e_flags())
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opd_shndx_(0), e_flags_(ehdr.get_e_flags()), opd_ent_()
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{
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this->set_abiversion(0);
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}
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@ -548,14 +558,14 @@ private:
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unsigned int opd_shndx_;
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Address opd_address_;
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// Header e_flags
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elfcpp::Elf_Word e_flags_;
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// The first 8-byte word of an OPD entry gives the address of the
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// entry point of the function. Records the section and offset
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// corresponding to the address. Note that in dynamic objects,
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// offset is *not* relative to the section.
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std::vector<Opd_ent> opd_ent_;
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// Header e_flags
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elfcpp::Elf_Word e_flags_;
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};
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// Powerpc_copy_relocs class. Needed to peek at dynamic relocs the
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@ -935,6 +945,23 @@ class Target_powerpc : public Sized_target<size, big_endian>
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}
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}
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// Wrapper used after relax to define a local symbol in output data,
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// from the end if value < 0.
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void
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define_local(Symbol_table* symtab, const char* name,
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Output_data* od, Address value, unsigned int symsize)
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{
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Symbol* sym
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= symtab->define_in_output_data(name, NULL, Symbol_table::PREDEFINED,
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od, value, symsize, elfcpp::STT_NOTYPE,
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elfcpp::STB_LOCAL, elfcpp::STV_HIDDEN, 0,
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static_cast<Signed_address>(value) < 0,
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false);
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// We are creating this symbol late, so need to fix up things
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// done early in Layout::finalize.
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sym->set_dynsym_index(-1U);
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}
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bool
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plt_thread_safe() const
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{ return this->plt_thread_safe_; }
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@ -2836,7 +2863,8 @@ Target_powerpc<size, big_endian>::group_sections(Layout* layout,
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if ((*t)->owner->is_input_section())
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stub_table = new Stub_table<size, big_endian>(this,
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(*t)->output_section,
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(*t)->owner);
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(*t)->owner,
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this->stub_tables_.size());
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else if ((*t)->owner->is_relaxed_input_section())
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stub_table = static_cast<Stub_table<size, big_endian>*>(
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(*t)->owner->relaxed_input_section());
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@ -3232,6 +3260,36 @@ Target_powerpc<size, big_endian>::do_relax(int pass,
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}
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this->brlt_section_->finalize_brlt_sizes();
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}
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if (!again
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&& (parameters->options().user_set_emit_stub_syms()
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? parameters->options().emit_stub_syms()
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: (size == 64
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|| parameters->options().output_is_position_independent()
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|| parameters->options().emit_relocs())))
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{
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for (typename Stub_tables::iterator p = this->stub_tables_.begin();
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p != this->stub_tables_.end();
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++p)
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(*p)->define_stub_syms(symtab);
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if (this->glink_ != NULL)
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{
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int stub_size = this->glink_->pltresolve_size;
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Address value = -stub_size;
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if (size == 64)
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{
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value = 8;
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stub_size -= 8;
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}
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this->define_local(symtab, "__glink_PLTresolve",
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this->glink_, value, stub_size);
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if (size != 64)
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this->define_local(symtab, "__glink", this->glink_, 0, 0);
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}
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}
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return again;
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}
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@ -3857,7 +3915,8 @@ class Stub_table : public Output_relaxed_input_section
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Stub_table(Target_powerpc<size, big_endian>* targ,
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Output_section* output_section,
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const Output_section::Input_section* owner)
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const Output_section::Input_section* owner,
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uint32_t id)
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: Output_relaxed_input_section(owner->relobj(), owner->shndx(),
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owner->relobj()
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->section_addralign(owner->shndx())),
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@ -3865,7 +3924,7 @@ class Stub_table : public Output_relaxed_input_section
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orig_data_size_(owner->current_data_size()),
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plt_size_(0), last_plt_size_(0),
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branch_size_(0), last_branch_size_(0), min_size_threshold_(0),
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eh_frame_added_(false), need_save_res_(false)
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eh_frame_added_(false), need_save_res_(false), uniq_(id)
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{
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this->set_output_section(output_section);
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@ -3986,9 +4045,13 @@ class Stub_table : public Output_relaxed_input_section
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plt_size() const
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{ return this->plt_size_; }
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void set_min_size_threshold(Address min_size)
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void
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set_min_size_threshold(Address min_size)
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{ this->min_size_threshold_ = min_size; }
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void
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define_stub_syms(Symbol_table*);
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bool
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size_update()
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{
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@ -4058,6 +4121,10 @@ class Stub_table : public Output_relaxed_input_section
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class Plt_stub_ent_hash;
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typedef Unordered_map<Plt_stub_ent, unsigned int,
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Plt_stub_ent_hash> Plt_stub_entries;
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class Branch_stub_ent;
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class Branch_stub_ent_hash;
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typedef Unordered_map<Branch_stub_ent, unsigned int,
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Branch_stub_ent_hash> Branch_stub_entries;
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// Alignment of stub section.
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unsigned int
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@ -4126,11 +4193,10 @@ class Stub_table : public Output_relaxed_input_section
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// Return long branch stub size.
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unsigned int
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branch_stub_size(Address to)
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branch_stub_size(typename Branch_stub_entries::const_iterator p)
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{
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Address loc
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= this->stub_address() + this->last_plt_size_ + this->branch_size_;
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if (to - loc + (1 << 25) < 2 << 25)
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Address loc = this->stub_address() + this->last_plt_size_ + p->second;
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if (p->first.dest_ - loc + (1 << 25) < 2 << 25)
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return 4;
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if (size == 64 || !parameters->options().output_is_position_independent())
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return 16;
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@ -4196,6 +4262,7 @@ class Stub_table : public Output_relaxed_input_section
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const Sized_relobj_file<size, big_endian>* object_;
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typename elfcpp::Elf_types<size>::Elf_Addr addend_;
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unsigned int locsym_;
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unsigned int indx_;
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};
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class Plt_stub_ent_hash
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@ -4246,8 +4313,6 @@ class Stub_table : public Output_relaxed_input_section
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// Map sym/object/addend to stub offset.
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Plt_stub_entries plt_call_stubs_;
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// Map destination address to stub offset.
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typedef Unordered_map<Branch_stub_ent, unsigned int,
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Branch_stub_ent_hash> Branch_stub_entries;
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Branch_stub_entries long_branch_stubs_;
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// size of input section
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section_size_type orig_data_size_;
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@ -4265,6 +4330,8 @@ class Stub_table : public Output_relaxed_input_section
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// Set if this stub group needs a copy of out-of-line register
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// save/restore functions.
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bool need_save_res_;
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// Per stub table unique identifier.
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uint32_t uniq_;
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};
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// Add a plt call stub, if we do not already have one for this
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@ -4281,6 +4348,7 @@ Stub_table<size, big_endian>::add_plt_call_entry(
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{
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Plt_stub_ent ent(object, gsym, r_type, addend);
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unsigned int off = this->plt_size_;
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ent.indx_ = this->plt_call_stubs_.size();
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std::pair<typename Plt_stub_entries::iterator, bool> p
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= this->plt_call_stubs_.insert(std::make_pair(ent, off));
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if (p.second)
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@ -4299,6 +4367,7 @@ Stub_table<size, big_endian>::add_plt_call_entry(
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{
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Plt_stub_ent ent(object, locsym_index, r_type, addend);
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unsigned int off = this->plt_size_;
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ent.indx_ = this->plt_call_stubs_.size();
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std::pair<typename Plt_stub_entries::iterator, bool> p
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= this->plt_call_stubs_.insert(std::make_pair(ent, off));
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if (p.second)
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@ -4368,13 +4437,15 @@ Stub_table<size, big_endian>::add_long_branch_entry(
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{
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Branch_stub_ent ent(object, to, save_res);
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Address off = this->branch_size_;
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if (this->long_branch_stubs_.insert(std::make_pair(ent, off)).second)
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std::pair<typename Branch_stub_entries::iterator, bool> p
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= this->long_branch_stubs_.insert(std::make_pair(ent, off));
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if (p.second)
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{
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if (save_res)
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this->need_save_res_ = true;
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else
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{
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unsigned int stub_size = this->branch_stub_size(to);
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unsigned int stub_size = this->branch_stub_size(p.first);
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this->branch_size_ = off + stub_size;
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if (size == 64 && stub_size != 4)
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this->targ_->add_branch_lookup_table(to);
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@ -4555,6 +4626,73 @@ Output_data_glink<size, big_endian>::set_final_data_size()
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this->set_data_size(total);
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}
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// Define symbols on stubs, identifying the stub.
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template<int size, bool big_endian>
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void
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Stub_table<size, big_endian>::define_stub_syms(Symbol_table* symtab)
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{
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if (!this->plt_call_stubs_.empty())
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{
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// The key for the plt call stub hash table includes addresses,
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// therefore traversal order depends on those addresses, which
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// can change between runs if gold is a PIE. Unfortunately the
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// output .symtab ordering depends on the order in which symbols
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// are added to the linker symtab. We want reproducible output
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// so must sort the call stub symbols.
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typedef typename Plt_stub_entries::const_iterator plt_iter;
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std::vector<plt_iter> sorted;
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sorted.resize(this->plt_call_stubs_.size());
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for (plt_iter cs = this->plt_call_stubs_.begin();
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cs != this->plt_call_stubs_.end();
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++cs)
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sorted[cs->first.indx_] = cs;
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for (unsigned int i = 0; i < this->plt_call_stubs_.size(); ++i)
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{
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plt_iter cs = sorted[i];
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char add[10];
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add[0] = 0;
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if (cs->first.addend_ != 0)
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sprintf(add, "+%x", static_cast<uint32_t>(cs->first.addend_));
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char localname[18];
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const char *symname;
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if (cs->first.sym_ == NULL)
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{
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const Powerpc_relobj<size, big_endian>* ppcobj = static_cast
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<const Powerpc_relobj<size, big_endian>*>(cs->first.object_);
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sprintf(localname, "%x:%x", ppcobj->uniq(), cs->first.locsym_);
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symname = localname;
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}
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else
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symname = cs->first.sym_->name();
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char* name = new char[8 + 10 + strlen(symname) + strlen(add) + 1];
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sprintf(name, "%08x.plt_call.%s%s", this->uniq_, symname, add);
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Address value = this->stub_address() - this->address() + cs->second;
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unsigned int stub_size = this->plt_call_size(cs);
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this->targ_->define_local(symtab, name, this, value, stub_size);
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}
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}
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typedef typename Branch_stub_entries::const_iterator branch_iter;
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for (branch_iter bs = this->long_branch_stubs_.begin();
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||||
bs != this->long_branch_stubs_.end();
|
||||
++bs)
|
||||
{
|
||||
if (bs->first.save_res_)
|
||||
continue;
|
||||
|
||||
char* name = new char[8 + 13 + 16 + 1];
|
||||
sprintf(name, "%08x.long_branch.%llx", this->uniq_,
|
||||
static_cast<unsigned long long>(bs->first.dest_));
|
||||
Address value = (this->stub_address() - this->address()
|
||||
+ this->plt_size_ + bs->second);
|
||||
unsigned int stub_size = this->branch_stub_size(bs);
|
||||
this->targ_->define_local(symtab, name, this, value, stub_size);
|
||||
}
|
||||
}
|
||||
|
||||
// Write out plt and long branch stub code.
|
||||
|
||||
template<int size, bool big_endian>
|
||||
|
|
|
|||
Loading…
Reference in New Issue