// ehframe.cc -- handle exception frame sections for gold
-// Copyright 2006, 2007, 2008, 2010, 2011, 2012 Free Software Foundation, Inc.
+// Copyright (C) 2006-2020 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// Class Fde.
// Write the FDE to OVIEW starting at OFFSET. CIE_OFFSET is the
-// offset of the CIE in OVIEW. FDE_ENCODING is the encoding, from the
-// CIE. ADDRALIGN is the required alignment. ADDRESS is the virtual
-// address of OVIEW. Record the FDE pc for EH_FRAME_HDR. Return the
-// new offset.
+// offset of the CIE in OVIEW. OUTPUT_OFFSET is the offset of the
+// Eh_frame section within the output section. FDE_ENCODING is the
+// encoding, from the CIE. ADDRALIGN is the required alignment.
+// ADDRESS is the virtual address of OVIEW. Record the FDE pc for
+// EH_FRAME_HDR. Return the new offset.
template<int size, bool big_endian>
section_offset_type
-Fde::write(unsigned char* oview, section_offset_type offset,
- uint64_t address, unsigned int addralign,
+Fde::write(unsigned char* oview, section_offset_type output_offset,
+ section_offset_type offset, uint64_t address, unsigned int addralign,
section_offset_type cie_offset, unsigned char fde_encoding,
Eh_frame_hdr* eh_frame_hdr)
{
// Tell the exception frame header about this FDE.
if (eh_frame_hdr != NULL)
- eh_frame_hdr->record_fde(offset, fde_encoding);
+ eh_frame_hdr->record_fde(output_offset + offset, fde_encoding);
return offset + aligned_full_length;
}
section_offset_type
Cie::set_output_offset(section_offset_type output_offset,
unsigned int addralign,
- Merge_map* merge_map)
+ Output_section_data *output_data)
{
size_t length = this->contents_.length();
if (this->object_ != NULL)
{
// Add a mapping so that relocations are applied correctly.
- merge_map->add_mapping(this->object_, this->shndx_, this->input_offset_,
- length, output_offset);
+ this->object_->add_merge_mapping(output_data, this->shndx_,
+ this->input_offset_, length,
+ output_offset);
}
length = align_address(length, addralign);
p != this->fdes_.end();
++p)
{
- (*p)->add_mapping(output_offset + length, merge_map);
+ (*p)->add_mapping(output_offset + length, output_data);
size_t fde_length = (*p)->length();
fde_length = align_address(fde_length, addralign);
return output_offset + length;
}
-// Write the CIE to OVIEW starting at OFFSET. Round up the bytes to
-// ADDRALIGN. ADDRESS is the virtual address of OVIEW.
+// Write the CIE to OVIEW starting at OFFSET. OUTPUT_OFFSET is the
+// offset of the Eh_frame section within the output section. Round up
+// the bytes to ADDRALIGN. ADDRESS is the virtual address of OVIEW.
// EH_FRAME_HDR is the exception frame header for FDE recording.
// POST_FDES stashes FDEs created after mappings were done, for later
// writing. Return the new offset.
template<int size, bool big_endian>
section_offset_type
-Cie::write(unsigned char* oview, section_offset_type offset,
- uint64_t address, unsigned int addralign,
- Eh_frame_hdr* eh_frame_hdr, Post_fdes* post_fdes)
+Cie::write(unsigned char* oview, section_offset_type output_offset,
+ section_offset_type offset, uint64_t address,
+ unsigned int addralign, Eh_frame_hdr* eh_frame_hdr,
+ Post_fdes* post_fdes)
{
gold_assert((offset & (addralign - 1)) == 0);
if ((*p)->post_map())
post_fdes->push_back(Post_fde(*p, cie_offset, fde_encoding));
else
- offset = (*p)->write<size, big_endian>(oview, offset, address,
- addralign, cie_offset,
+ offset = (*p)->write<size, big_endian>(oview, output_offset, offset,
+ address, addralign, cie_offset,
fde_encoding, eh_frame_hdr);
}
eh_frame_hdr_(NULL),
cie_offsets_(),
unmergeable_cie_offsets_(),
- merge_map_(),
mappings_are_done_(false),
final_data_size_(0)
{
// section.
template<int size, bool big_endian>
-bool
+Eh_frame::Eh_frame_section_disposition
Eh_frame::add_ehframe_input_section(
Sized_relobj_file<size, big_endian>* object,
const unsigned char* symbols,
&contents_len,
false);
if (contents_len == 0)
- return false;
+ return EH_EMPTY_SECTION;
// If this is the marker section for the end of the data, then
// return false to force it to be handled as an ordinary input
// of unrecognized .eh_frame sections.
if (contents_len == 4
&& elfcpp::Swap<32, big_endian>::readval(pcontents) == 0)
- return false;
+ return EH_END_MARKER_SECTION;
New_cies new_cies;
if (!this->do_add_ehframe_input_section(object, symbols, symbols_size,
++p)
delete p->first;
- return false;
+ return EH_UNRECOGNIZED_SECTION;
}
// Now that we know we are using this section, record any new CIEs
this->unmergeable_cie_offsets_.push_back(p->first);
}
- return true;
+ return EH_OPTIMIZABLE_SECTION;
}
// The bulk of the implementation of add_ehframe_input_section.
// know for sure that we are doing a special mapping for this
// input section, but that's OK--if we don't do a special
// mapping, nobody will ever ask for the mapping we add here.
- this->merge_map_.add_mapping(object, shndx, (pcie - 8) - pcontents,
- pcieend - (pcie - 8), -1);
+ object->add_merge_mapping(this, shndx, (pcie - 8) - pcontents,
+ pcieend - (pcie - 8), -1);
}
// Record this CIE plus the offset in the input section.
return false;
Cie* cie = pcie->second;
+ int pc_size = 0;
+ switch (cie->fde_encoding() & 7)
+ {
+ case elfcpp::DW_EH_PE_udata2:
+ pc_size = 2;
+ break;
+ case elfcpp::DW_EH_PE_udata4:
+ pc_size = 4;
+ break;
+ case elfcpp::DW_EH_PE_udata8:
+ gold_assert(size == 64);
+ pc_size = 8;
+ break;
+ case elfcpp::DW_EH_PE_absptr:
+ pc_size = size == 32 ? 4 : 8;
+ break;
+ default:
+ // All other cases were rejected in Eh_frame::read_cie.
+ gold_unreachable();
+ }
+
// The FDE should start with a reloc to the start of the code which
// it describes.
if (relocs->advance(pfde - pcontents) > 0)
return false;
-
if (relocs->next_offset() != pfde - pcontents)
- return false;
+ {
+ // In an object produced by a relocatable link, gold may have
+ // discarded a COMDAT group in the previous link, but not the
+ // corresponding FDEs. In that case, gold will have discarded
+ // the relocations, so the FDE will have a non-relocatable zero
+ // (regardless of whether the PC encoding is absolute, pc-relative,
+ // or data-relative) instead of a pointer to the start of the code.
+
+ uint64_t pc_value = 0;
+ switch (pc_size)
+ {
+ case 2:
+ pc_value = elfcpp::Swap<16, big_endian>::readval(pfde);
+ break;
+ case 4:
+ pc_value = elfcpp::Swap<32, big_endian>::readval(pfde);
+ break;
+ case 8:
+ pc_value = elfcpp::Swap_unaligned<64, big_endian>::readval(pfde);
+ break;
+ default:
+ gold_unreachable();
+ }
+
+ if (pc_value == 0)
+ {
+ // This FDE applies to a discarded function. We
+ // can discard this FDE.
+ object->add_merge_mapping(this, shndx, (pfde - 8) - pcontents,
+ pfdeend - (pfde - 8), -1);
+ return true;
+ }
+
+ // Otherwise, reject the FDE.
+ return false;
+ }
unsigned int symndx = relocs->next_symndx();
if (symndx == -1U)
// pointer to a PC relative offset when generating a shared library.
relocs->advance(pfdeend - pcontents);
+ // Find the section index for code that this FDE describes.
+ // If we have discarded the section, we can also discard the FDE.
unsigned int fde_shndx;
const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
if (symndx >= symbols_size / sym_size)
bool is_ordinary;
fde_shndx = object->adjust_sym_shndx(symndx, sym.get_st_shndx(),
&is_ordinary);
+ bool is_discarded = (is_ordinary
+ && fde_shndx != elfcpp::SHN_UNDEF
+ && fde_shndx < object->shnum()
+ && !object->is_section_included(fde_shndx));
+
+ // Fetch the address range field from the FDE. The offset and size
+ // of the field depends on the PC encoding given in the CIE, but
+ // it is always an absolute value. If the address range is 0, this
+ // FDE corresponds to a function that was discarded during optimization
+ // (too late to discard the corresponding FDE).
+ uint64_t address_range = 0;
+ switch (pc_size)
+ {
+ case 2:
+ address_range = elfcpp::Swap<16, big_endian>::readval(pfde + 2);
+ break;
+ case 4:
+ address_range = elfcpp::Swap<32, big_endian>::readval(pfde + 4);
+ break;
+ case 8:
+ address_range = elfcpp::Swap_unaligned<64, big_endian>::readval(pfde + 8);
+ break;
+ default:
+ gold_unreachable();
+ }
- if (is_ordinary
- && fde_shndx != elfcpp::SHN_UNDEF
- && fde_shndx < object->shnum()
- && !object->is_section_included(fde_shndx))
+ if (is_discarded || address_range == 0)
{
- // This FDE applies to a section which we are discarding. We
+ // This FDE applies to a discarded function. We
// can discard this FDE.
- this->merge_map_.add_mapping(object, shndx, (pfde - 8) - pcontents,
- pfdeend - (pfde - 8), -1);
+ object->add_merge_mapping(this, shndx, (pfde - 8) - pcontents,
+ pfdeend - (pfde - 8), -1);
return true;
}
this->final_data_size_ += align_address(fde_length + 8, this->addralign());
}
+// Remove all post-map unwind information for a PLT.
+
+void
+Eh_frame::remove_ehframe_for_plt(Output_data* plt,
+ const unsigned char* cie_data,
+ size_t cie_length)
+{
+ if (!this->mappings_are_done_)
+ return;
+
+ Cie cie(NULL, 0, 0, elfcpp::DW_EH_PE_pcrel | elfcpp::DW_EH_PE_sdata4, "",
+ cie_data, cie_length);
+ Cie_offsets::iterator find_cie = this->cie_offsets_.find(&cie);
+ gold_assert (find_cie != this->cie_offsets_.end());
+ Cie* pcie = *find_cie;
+
+ while (pcie->fde_count() != 0)
+ {
+ const Fde* fde = pcie->last_fde();
+ if (!fde->post_map(plt))
+ break;
+ size_t length = fde->length();
+ this->final_data_size_ -= align_address(length + 8, this->addralign());
+ pcie->remove_fde();
+ }
+}
+
// Return the number of FDEs.
unsigned int
return;
}
- section_offset_type output_offset = 0;
+ section_offset_type output_start = 0;
+ if (this->is_offset_valid())
+ output_start = this->offset() - this->output_section()->offset();
+ section_offset_type output_offset = output_start;
for (Unmergeable_cie_offsets::iterator p =
this->unmergeable_cie_offsets_.begin();
++p)
output_offset = (*p)->set_output_offset(output_offset,
this->addralign(),
- &this->merge_map_);
+ this);
for (Cie_offsets::iterator p = this->cie_offsets_.begin();
p != this->cie_offsets_.end();
++p)
output_offset = (*p)->set_output_offset(output_offset,
this->addralign(),
- &this->merge_map_);
+ this);
this->mappings_are_done_ = true;
- this->final_data_size_ = output_offset;
+ this->final_data_size_ = output_offset - output_start;
gold_assert((output_offset & (this->addralign() - 1)) == 0);
- this->set_data_size(output_offset);
+ this->set_data_size(this->final_data_size_);
}
// Return an output offset for an input offset.
section_offset_type offset,
section_offset_type* poutput) const
{
- return this->merge_map_.get_output_offset(object, shndx, offset, poutput);
-}
-
-// Return whether this is the merge section for an input section.
-
-bool
-Eh_frame::do_is_merge_section_for(const Relobj* object,
- unsigned int shndx) const
-{
- return this->merge_map_.is_merge_section_for(object, shndx);
+ return object->merge_output_offset(shndx, offset, poutput);
}
// Write the data to the output file.
uint64_t address = this->address();
unsigned int addralign = this->addralign();
section_offset_type o = 0;
+ const off_t output_offset = this->offset() - this->output_section()->offset();
Post_fdes post_fdes;
for (Unmergeable_cie_offsets::iterator p =
this->unmergeable_cie_offsets_.begin();
p != this->unmergeable_cie_offsets_.end();
++p)
- o = (*p)->write<size, big_endian>(oview, o, address, addralign,
- this->eh_frame_hdr_, &post_fdes);
+ o = (*p)->write<size, big_endian>(oview, output_offset, o, address,
+ addralign, this->eh_frame_hdr_,
+ &post_fdes);
for (Cie_offsets::iterator p = this->cie_offsets_.begin();
p != this->cie_offsets_.end();
++p)
- o = (*p)->write<size, big_endian>(oview, o, address, addralign,
- this->eh_frame_hdr_, &post_fdes);
+ o = (*p)->write<size, big_endian>(oview, output_offset, o, address,
+ addralign, this->eh_frame_hdr_,
+ &post_fdes);
for (Post_fdes::iterator p = post_fdes.begin();
p != post_fdes.end();
++p)
- o = (*p).fde->write<size, big_endian>(oview, o, address, addralign,
- (*p).cie_offset,
+ o = (*p).fde->write<size, big_endian>(oview, output_offset, o, address,
+ addralign, (*p).cie_offset,
(*p).fde_encoding,
this->eh_frame_hdr_);
}
#ifdef HAVE_TARGET_32_LITTLE
template
-bool
+Eh_frame::Eh_frame_section_disposition
Eh_frame::add_ehframe_input_section<32, false>(
Sized_relobj_file<32, false>* object,
const unsigned char* symbols,
#ifdef HAVE_TARGET_32_BIG
template
-bool
+Eh_frame::Eh_frame_section_disposition
Eh_frame::add_ehframe_input_section<32, true>(
Sized_relobj_file<32, true>* object,
const unsigned char* symbols,
#ifdef HAVE_TARGET_64_LITTLE
template
-bool
+Eh_frame::Eh_frame_section_disposition
Eh_frame::add_ehframe_input_section<64, false>(
Sized_relobj_file<64, false>* object,
const unsigned char* symbols,
#ifdef HAVE_TARGET_64_BIG
template
-bool
+Eh_frame::Eh_frame_section_disposition
Eh_frame::add_ehframe_input_section<64, true>(
Sized_relobj_file<64, true>* object,
const unsigned char* symbols,
projects / deliverable / binutils-gdb.git / blobdiff