// merge.cc -- handle section merging for gold
-// Copyright 2006, 2007 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#include "gold.h"
#include <cstdlib>
+#include <algorithm>
#include "merge.h"
namespace gold
{
-// Sort the entries in a merge mapping. The key is an input object, a
-// section index in that object, and an offset in that section.
+// Class Object_merge_map.
-bool
-Output_merge_base::Merge_key_less::operator()(const Merge_key& mk1,
- const Merge_key& mk2) const
+// Destructor.
+
+Object_merge_map::~Object_merge_map()
+{
+ for (Section_merge_maps::iterator p = this->section_merge_maps_.begin();
+ p != this->section_merge_maps_.end();
+ ++p)
+ delete p->second;
+}
+
+// Get the Input_merge_map to use for an input section, or NULL.
+
+Object_merge_map::Input_merge_map*
+Object_merge_map::get_input_merge_map(unsigned int shndx)
{
- // The order of different objects and different sections doesn't
- // matter. We want to get consistent results across links so we
- // don't use pointer comparison.
- if (mk1.object != mk2.object)
+ gold_assert(shndx != -1U);
+ if (shndx == this->first_shnum_)
+ return &this->first_map_;
+ if (shndx == this->second_shnum_)
+ return &this->second_map_;
+ Section_merge_maps::const_iterator p = this->section_merge_maps_.find(shndx);
+ if (p != this->section_merge_maps_.end())
+ return p->second;
+ return NULL;
+}
+
+// Get or create the Input_merge_map to use for an input section.
+
+Object_merge_map::Input_merge_map*
+Object_merge_map::get_or_make_input_merge_map(const Merge_map* merge_map,
+ unsigned int shndx)
+{
+ Input_merge_map* map = this->get_input_merge_map(shndx);
+ if (map != NULL)
{
- // Two different object files can have the same name: if foo.a
- // includes both bar/qux.o and baz/qux.o, then both end up with
- // the name foo.a(qux.o). But it's impossible for two different
- // object files to have both the same name and the same offset.
- if (mk1.object->offset() != mk2.object->offset())
- return mk1.object->offset() < mk2.object->offset();
- return mk1.object->name() < mk2.object->name();
+ // For a given input section in a given object, every mapping
+ // must be done with the same Merge_map.
+ gold_assert(map->merge_map == merge_map);
+ return map;
}
- if (mk1.shndx != mk2.shndx)
- return mk1.shndx < mk2.shndx;
- return mk1.offset < mk2.offset;
+
+ // We need to create a new entry.
+ if (this->first_shnum_ == -1U)
+ {
+ this->first_shnum_ = shndx;
+ this->first_map_.merge_map = merge_map;
+ return &this->first_map_;
+ }
+ if (this->second_shnum_ == -1U)
+ {
+ this->second_shnum_ = shndx;
+ this->second_map_.merge_map = merge_map;
+ return &this->second_map_;
+ }
+
+ Input_merge_map* new_map = new Input_merge_map;
+ new_map->merge_map = merge_map;
+ this->section_merge_maps_[shndx] = new_map;
+ return new_map;
}
-// Add a mapping from an OFFSET in input section SHNDX in object
-// OBJECT to an OUTPUT_OFFSET in a merged output section. This
-// manages the mapping used to resolve relocations against merged
-// sections.
+// Add a mapping.
void
-Output_merge_base::add_mapping(Relobj* object, unsigned int shndx,
- off_t offset, off_t output_offset)
-{
- Merge_key mk;
- mk.object = object;
- mk.shndx = shndx;
- mk.offset = offset;
- std::pair<Merge_map::iterator, bool> ins =
- this->merge_map_.insert(std::make_pair(mk, output_offset));
- gold_assert(ins.second);
+Object_merge_map::add_mapping(const Merge_map* merge_map, unsigned int shndx,
+ section_offset_type input_offset,
+ section_size_type length,
+ section_offset_type output_offset)
+{
+ Input_merge_map* map = this->get_or_make_input_merge_map(merge_map, shndx);
+
+ // Try to merge the new entry in the last one we saw.
+ if (!map->entries.empty())
+ {
+ Input_merge_entry& entry(map->entries.back());
+
+ // Use section_size_type to avoid signed/unsigned warnings.
+ section_size_type input_offset_u = input_offset;
+ section_size_type output_offset_u = output_offset;
+
+ // If this entry is not in order, we need to sort the vector
+ // before looking anything up.
+ if (input_offset_u < entry.input_offset + entry.length)
+ {
+ gold_assert(input_offset < entry.input_offset);
+ gold_assert(input_offset_u + length
+ <= static_cast<section_size_type>(entry.input_offset));
+ map->sorted = false;
+ }
+ else if (entry.input_offset + entry.length == input_offset_u
+ && (output_offset == -1
+ ? entry.output_offset == -1
+ : entry.output_offset + entry.length == output_offset_u))
+ {
+ entry.length += length;
+ return;
+ }
+ }
+
+ Input_merge_entry entry;
+ entry.input_offset = input_offset;
+ entry.length = length;
+ entry.output_offset = output_offset;
+ map->entries.push_back(entry);
}
-// Return the output address for an input address. The input address
-// is at offset OFFSET in section SHNDX in OBJECT.
-// OUTPUT_SECTION_ADDRESS is the address of the output section. If we
-// know the address, set *POUTPUT and return true. Otherwise return
-// false.
+// Get the output offset for an input address.
bool
-Output_merge_base::do_output_address(const Relobj* object, unsigned int shndx,
- off_t offset,
- uint64_t output_section_address,
- uint64_t* poutput) const
-{
- gold_assert(output_section_address == this->address());
-
- Merge_key mk;
- mk.object = object;
- mk.shndx = shndx;
- mk.offset = offset;
- Merge_map::const_iterator p = this->merge_map_.lower_bound(mk);
-
- // If MK is not in the map, lower_bound returns the next iterator
- // larger than it.
- if (p == this->merge_map_.end()
- || p->first.object != object
- || p->first.shndx != shndx
- || p->first.offset != offset)
+Object_merge_map::get_output_offset(const Merge_map* merge_map,
+ unsigned int shndx,
+ section_offset_type input_offset,
+ section_offset_type *output_offset)
+{
+ Input_merge_map* map = this->get_input_merge_map(shndx);
+ if (map == NULL
+ || (merge_map != NULL && map->merge_map != merge_map))
+ return false;
+
+ if (!map->sorted)
+ {
+ std::sort(map->entries.begin(), map->entries.end(),
+ Input_merge_compare());
+ map->sorted = true;
+ }
+
+ Input_merge_entry entry;
+ entry.input_offset = input_offset;
+ std::vector<Input_merge_entry>::const_iterator p =
+ std::lower_bound(map->entries.begin(), map->entries.end(),
+ entry, Input_merge_compare());
+ if (p == map->entries.end() || p->input_offset > input_offset)
{
- if (p == this->merge_map_.begin())
+ if (p == map->entries.begin())
return false;
--p;
+ gold_assert(p->input_offset <= input_offset);
}
- if (p->first.object != object || p->first.shndx != shndx)
+ if (input_offset - p->input_offset
+ >= static_cast<section_offset_type>(p->length))
return false;
- // Any input section is fully mapped: we don't need to know the size
- // of the range starting at P->FIRST.OFFSET.
- *poutput = output_section_address + p->second + (offset - p->first.offset);
+ *output_offset = p->output_offset;
+ if (*output_offset != -1)
+ *output_offset += (input_offset - p->input_offset);
return true;
}
+// Return whether this is the merge map for section SHNDX.
+
+inline bool
+Object_merge_map::is_merge_section_for(const Merge_map* merge_map,
+ unsigned int shndx)
+{
+ Input_merge_map* map = this->get_input_merge_map(shndx);
+ return map != NULL && map->merge_map == merge_map;
+}
+
+// Initialize a mapping from input offsets to output addresses.
+
+template<int size>
+void
+Object_merge_map::initialize_input_to_output_map(
+ unsigned int shndx,
+ typename elfcpp::Elf_types<size>::Elf_Addr starting_address,
+ Unordered_map<section_offset_type,
+ typename elfcpp::Elf_types<size>::Elf_Addr>* initialize_map)
+{
+ Input_merge_map* map = this->get_input_merge_map(shndx);
+ gold_assert(map != NULL);
+
+ gold_assert(initialize_map->empty());
+ // We know how many entries we are going to add.
+ // reserve_unordered_map takes an expected count of buckets, not a
+ // count of elements, so double it to try to reduce collisions.
+ reserve_unordered_map(initialize_map, map->entries.size() * 2);
+
+ for (Input_merge_map::Entries::const_iterator p = map->entries.begin();
+ p != map->entries.end();
+ ++p)
+ {
+ section_offset_type output_offset = p->output_offset;
+ if (output_offset != -1)
+ output_offset += starting_address;
+ else
+ {
+ // If we see a relocation against an address we have chosen
+ // to discard, we relocate to zero. FIXME: We could also
+ // issue a warning in this case; that would require
+ // reporting this somehow and checking it in the routines in
+ // reloc.h.
+ output_offset = 0;
+ }
+ initialize_map->insert(std::make_pair(p->input_offset, output_offset));
+ }
+}
+
+// Class Merge_map.
+
+// Add a mapping for the bytes from OFFSET to OFFSET + LENGTH in input
+// section SHNDX in object OBJECT to an OUTPUT_OFFSET in merged data
+// in an output section.
+
+void
+Merge_map::add_mapping(Relobj* object, unsigned int shndx,
+ section_offset_type offset, section_size_type length,
+ section_offset_type output_offset)
+{
+ Object_merge_map* object_merge_map = object->merge_map();
+ if (object_merge_map == NULL)
+ {
+ object_merge_map = new Object_merge_map();
+ object->set_merge_map(object_merge_map);
+ }
+
+ object_merge_map->add_mapping(this, shndx, offset, length, output_offset);
+}
+
+// Return the output offset for an input address. The input address
+// is at offset OFFSET in section SHNDX in OBJECT. This sets
+// *OUTPUT_OFFSET to the offset in the merged data in the output
+// section. This returns true if the mapping is known, false
+// otherwise.
+
+bool
+Merge_map::get_output_offset(const Relobj* object, unsigned int shndx,
+ section_offset_type offset,
+ section_offset_type* output_offset) const
+{
+ Object_merge_map* object_merge_map = object->merge_map();
+ if (object_merge_map == NULL)
+ return false;
+ return object_merge_map->get_output_offset(this, shndx, offset,
+ output_offset);
+}
+
+// Return whether this is the merge section for SHNDX in OBJECT.
+
+bool
+Merge_map::is_merge_section_for(const Relobj* object, unsigned int shndx) const
+{
+ Object_merge_map* object_merge_map = object->merge_map();
+ if (object_merge_map == NULL)
+ return false;
+ return object_merge_map->is_merge_section_for(this, shndx);
+}
+
+// Class Output_merge_base.
+
+// Return the output offset for an input offset. The input address is
+// at offset OFFSET in section SHNDX in OBJECT. If we know the
+// offset, set *POUTPUT and return true. Otherwise return false.
+
+bool
+Output_merge_base::do_output_offset(const Relobj* object,
+ unsigned int shndx,
+ 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 SHNDX in OBJECT.
+
+bool
+Output_merge_base::do_is_merge_section_for(const Relobj* object,
+ unsigned int shndx) const
+{
+ return this->merge_map_.is_merge_section_for(object, shndx);
+}
+
+// Record a merged input section for script processing.
+
+void
+Output_merge_base::record_input_section(Relobj* relobj, unsigned int shndx)
+{
+ gold_assert(this->keeps_input_sections_ && relobj != NULL);
+ // If this is the first input section, record it. We need do this because
+ // this->input_sections_ is unordered.
+ if (this->first_relobj_ == NULL)
+ {
+ this->first_relobj_ = relobj;
+ this->first_shndx_ = shndx;
+ }
+
+ std::pair<Input_sections::iterator, bool> result =
+ this->input_sections_.insert(Section_id(relobj, shndx));
+ // We should insert a merge section once only.
+ gold_assert(result.second);
+}
+
+// Class Output_merge_data.
+
// Compute the hash code for a fixed-size constant.
size_t
Output_merge_data::Merge_data_hash::operator()(Merge_data_key k) const
{
const unsigned char* p = this->pomd_->constant(k);
- uint64_t entsize = this->pomd_->entsize();
+ section_size_type entsize =
+ convert_to_section_size_type(this->pomd_->entsize());
// Fowler/Noll/Vo (FNV) hash (type FNV-1a).
if (sizeof(size_t) == 8)
{
size_t result = static_cast<size_t>(14695981039346656037ULL);
- for (uint64_t i = 0; i < entsize; ++i)
+ for (section_size_type i = 0; i < entsize; ++i)
{
result &= (size_t) *p++;
result *= 1099511628211ULL;
else
{
size_t result = 2166136261UL;
- for (uint64_t i = 0; i < entsize; ++i)
+ for (section_size_type i = 0; i < entsize; ++i)
{
result ^= (size_t) *p++;
result *= 16777619UL;
void
Output_merge_data::add_constant(const unsigned char* p)
{
- uint64_t entsize = this->entsize();
- if (this->len_ + entsize > this->alc_)
+ section_size_type entsize = convert_to_section_size_type(this->entsize());
+ section_size_type addralign =
+ convert_to_section_size_type(this->addralign());
+ section_size_type addsize = std::max(entsize, addralign);
+ if (this->len_ + addsize > this->alc_)
{
if (this->alc_ == 0)
- this->alc_ = 128 * entsize;
+ this->alc_ = 128 * addsize;
else
this->alc_ *= 2;
this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->alc_));
}
memcpy(this->p_ + this->len_, p, entsize);
- this->len_ += entsize;
+ if (addsize > entsize)
+ memset(this->p_ + this->len_ + entsize, 0, addsize - entsize);
+ this->len_ += addsize;
}
// Add the input section SHNDX in OBJECT to a merged output section
bool
Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx)
{
- off_t len;
+ section_size_type len;
const unsigned char* p = object->section_contents(shndx, &len, false);
- uint64_t entsize = this->entsize();
+ section_size_type entsize = convert_to_section_size_type(this->entsize());
if (len % entsize != 0)
return false;
- for (off_t i = 0; i < len; i += entsize, p += entsize)
+ this->input_count_ += len / entsize;
+
+ for (section_size_type i = 0; i < len; i += entsize, p += entsize)
{
// Add the constant to the section contents. If we find that it
// is already in the hash table, we will remove it again.
}
// Record the offset of this constant in the output section.
- this->add_mapping(object, shndx, i, k);
+ this->add_mapping(object, shndx, i, entsize, k);
}
+ // For script processing, we keep the input sections.
+ if (this->keeps_input_sections())
+ record_input_section(object, shndx);
+
return true;
}
// constants.
void
-Output_merge_data::do_set_address(uint64_t, off_t)
+Output_merge_data::set_final_data_size()
{
// Release the memory we don't need.
this->p_ = static_cast<unsigned char*>(realloc(this->p_, this->len_));
- gold_assert(this->p_ != NULL);
+ // An Output_merge_data object may be empty and realloc is allowed
+ // to return a NULL pointer in this case. An Output_merge_data is empty
+ // if all its input sections have sizes that are not multiples of entsize.
+ gold_assert(this->p_ != NULL || this->len_ == 0);
this->set_data_size(this->len_);
}
of->write(this->offset(), this->p_, this->len_);
}
+// Write the data to a buffer.
+
+void
+Output_merge_data::do_write_to_buffer(unsigned char* buffer)
+{
+ memcpy(buffer, this->p_, this->len_);
+}
+
+// Print merge stats to stderr.
+
+void
+Output_merge_data::do_print_merge_stats(const char* section_name)
+{
+ fprintf(stderr,
+ _("%s: %s merged constants size: %lu; input: %zu; output: %zu\n"),
+ program_name, section_name,
+ static_cast<unsigned long>(this->entsize()),
+ this->input_count_, this->hashtable_.size());
+}
+
+// Class Output_merge_string.
+
// Add an input section to a merged string section.
template<typename Char_type>
Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
unsigned int shndx)
{
- off_t len;
+ section_size_type len;
const unsigned char* pdata = object->section_contents(shndx, &len, false);
const Char_type* p = reinterpret_cast<const Char_type*>(pdata);
+ const Char_type* pend = p + len / sizeof(Char_type);
if (len % sizeof(Char_type) != 0)
{
"character size"));
return false;
}
- len /= sizeof(Char_type);
- off_t i = 0;
+ size_t count = 0;
+
+ // The index I is in bytes, not characters.
+ section_size_type i = 0;
while (i < len)
{
- off_t plen = 0;
- for (const Char_type* pl = p; *pl != 0; ++pl)
+ const Char_type* pl;
+ for (pl = p; *pl != 0; ++pl)
{
- ++plen;
- if (i + plen >= len)
+ if (pl >= pend)
{
- object->error(_("entry in mergeable string section "
- "not null terminated"));
+ gold_warning(_("%s: last entry in mergeable string section '%s' "
+ "not null terminated"),
+ object->name().c_str(),
+ object->section_name(shndx).c_str());
break;
}
}
- const Char_type* str = this->stringpool_.add(p, true, NULL);
+ Stringpool::Key key;
+ const Char_type* str = this->stringpool_.add_with_length(p, pl - p, true,
+ &key);
- this->merged_strings_.push_back(Merged_string(object, shndx, i, str));
+ section_size_type bytelen_with_null = ((pl - p) + 1) * sizeof(Char_type);
+ this->merged_strings_.push_back(Merged_string(object, shndx, i, str,
+ bytelen_with_null, key));
- p += plen + 1;
- i += plen + 1;
+ p = pl + 1;
+ i += bytelen_with_null;
+ ++count;
}
+ this->input_count_ += count;
+
+ // For script processing, we keep the input sections.
+ if (this->keeps_input_sections())
+ record_input_section(object, shndx);
+
return true;
}
-// Set the final data size of a merged string section. This is where
-// we finalize the mappings from the input sections to the output
-// section.
+// Finalize the mappings from the input sections to the output
+// section, and return the final data size.
template<typename Char_type>
-void
-Output_merge_string<Char_type>::do_set_address(uint64_t, off_t)
+section_size_type
+Output_merge_string<Char_type>::finalize_merged_data()
{
this->stringpool_.set_string_offsets();
this->merged_strings_.begin();
p != this->merged_strings_.end();
++p)
- this->add_mapping(p->object, p->shndx, p->offset,
- this->stringpool_.get_offset(p->string));
-
- this->set_data_size(this->stringpool_.get_strtab_size());
+ {
+ section_offset_type offset =
+ this->stringpool_.get_offset_from_key(p->stringpool_key);
+ this->add_mapping(p->object, p->shndx, p->offset, p->length, offset);
+ }
- // Save some memory.
+ // Save some memory. This also ensures that this function will work
+ // if called twice, as may happen if Layout::set_segment_offsets
+ // finds a better alignment.
this->merged_strings_.clear();
+
+ return this->stringpool_.get_strtab_size();
+}
+
+template<typename Char_type>
+void
+Output_merge_string<Char_type>::set_final_data_size()
+{
+ const off_t final_data_size = this->finalize_merged_data();
+ this->set_data_size(final_data_size);
}
// Write out a merged string section.
this->stringpool_.write(of, this->offset());
}
+// Write a merged string section to a buffer.
+
+template<typename Char_type>
+void
+Output_merge_string<Char_type>::do_write_to_buffer(unsigned char* buffer)
+{
+ this->stringpool_.write_to_buffer(buffer, this->data_size());
+}
+
+// Return the name of the types of string to use with
+// do_print_merge_stats.
+
+template<typename Char_type>
+const char*
+Output_merge_string<Char_type>::string_name()
+{
+ gold_unreachable();
+ return NULL;
+}
+
+template<>
+const char*
+Output_merge_string<char>::string_name()
+{
+ return "strings";
+}
+
+template<>
+const char*
+Output_merge_string<uint16_t>::string_name()
+{
+ return "16-bit strings";
+}
+
+template<>
+const char*
+Output_merge_string<uint32_t>::string_name()
+{
+ return "32-bit strings";
+}
+
+// Print merge stats to stderr.
+
+template<typename Char_type>
+void
+Output_merge_string<Char_type>::do_print_merge_stats(const char* section_name)
+{
+ char buf[200];
+ snprintf(buf, sizeof buf, "%s merged %s", section_name, this->string_name());
+ fprintf(stderr, _("%s: %s input: %zu\n"),
+ program_name, buf, this->input_count_);
+ this->stringpool_.print_stats(buf);
+}
+
// Instantiate the templates we need.
template
template
class Output_merge_string<uint32_t>;
+#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_32_BIG)
+template
+void
+Object_merge_map::initialize_input_to_output_map<32>(
+ unsigned int shndx,
+ elfcpp::Elf_types<32>::Elf_Addr starting_address,
+ Unordered_map<section_offset_type, elfcpp::Elf_types<32>::Elf_Addr>*);
+#endif
+
+#if defined(HAVE_TARGET_64_LITTLE) || defined(HAVE_TARGET_64_BIG)
+template
+void
+Object_merge_map::initialize_input_to_output_map<64>(
+ unsigned int shndx,
+ elfcpp::Elf_types<64>::Elf_Addr starting_address,
+ Unordered_map<section_offset_type, elfcpp::Elf_types<64>::Elf_Addr>*);
+#endif
+
} // End namespace gold.