// merge.cc -- handle section merging for gold
-// Copyright 2006, 2007 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#include <algorithm>
#include "merge.h"
+#include "compressed_output.h"
namespace gold
{
-// For each object with merge sections, we store an Object_merge_map.
-// This is used to map locations in input sections to a merged output
-// section. The output section itself is not recorded here--it can be
-// found in the map_to_output_ field of the Object.
-
-class Object_merge_map
-{
- public:
- Object_merge_map()
- : first_shnum_(-1U), first_map_(),
- second_shnum_(-1U), second_map_(),
- section_merge_maps_()
- { }
-
- ~Object_merge_map();
-
- // Add a mapping for MERGE_MAP, for the bytes from OFFSET to OFFSET
- // + LENGTH in the input section SHNDX to OUTPUT_OFFSET in the
- // output section. An OUTPUT_OFFSET of -1 means that the bytes are
- // discarded.
- void
- add_mapping(const Merge_map*, unsigned int shndx, off_t offset, off_t length,
- off_t output_offset);
-
- // Get the output offset for an input address in MERGE_MAP. The
- // input address is at offset OFFSET in section SHNDX. This sets
- // *OUTPUT_OFFSET to the offset in the output section; this will be
- // -1 if the bytes are not being copied to the output. This returns
- // true if the mapping is known, false otherwise.
- bool
- get_output_offset(const Merge_map*, unsigned int shndx, off_t offset,
- off_t *output_offset);
-
- private:
- // Map input section offsets to a length and an output section
- // offset. An output section offset of -1 means that this part of
- // the input section is being discarded.
- struct Input_merge_entry
- {
- // The offset in the input section.
- off_t input_offset;
- // The length.
- off_t length;
- // The offset in the output section.
- off_t output_offset;
- };
-
- // A less-than comparison routine for Input_merge_entry.
- struct Input_merge_compare
- {
- bool
- operator()(const Input_merge_entry& i1, const Input_merge_entry& i2) const
- { return i1.input_offset < i2.input_offset; }
- };
-
- // A list of entries for a particular section.
- struct Input_merge_map
- {
- // The Merge_map for this section.
- const Merge_map* merge_map;
- // The list of mappings.
- std::vector<Input_merge_entry> entries;
- // Whether the ENTRIES field is sorted by input_offset.
- bool sorted;
-
- Input_merge_map()
- : merge_map(NULL), entries(), sorted(true)
- { }
- };
-
- // Map input section indices to merge maps.
- typedef std::map<unsigned int, Input_merge_map*> Section_merge_maps;
-
- // Return a pointer to the Input_merge_map to use for the input
- // section SHNDX, or NULL.
- Input_merge_map*
- get_input_merge_map(unsigned int shndx);
-
- // Get or make the the Input_merge_map to use for the section SHNDX
- // with MERGE_MAP.
- Input_merge_map*
- get_or_make_input_merge_map(const Merge_map* merge_map, unsigned int shndx);
-
- // Any given object file will normally only have a couple of input
- // sections with mergeable contents. So we keep the first two input
- // section numbers inline, and push any further ones into a map. A
- // value of -1U in first_shnum_ or second_shnum_ means that we don't
- // have a corresponding entry.
- unsigned int first_shnum_;
- Input_merge_map first_map_;
- unsigned int second_shnum_;
- Input_merge_map second_map_;
- Section_merge_maps section_merge_maps_;
-};
+// Class Object_merge_map.
// Destructor.
if (map != NULL)
{
// For a given input section in a given object, every mapping
- // must be donw with the same Merge_map.
+ // must be done with the same Merge_map.
gold_assert(map->merge_map == merge_map);
return map;
}
void
Object_merge_map::add_mapping(const Merge_map* merge_map, unsigned int shndx,
- off_t input_offset, off_t length,
- off_t output_offset)
+ 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);
{
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 < entry.input_offset + entry.length)
+ if (input_offset_u < entry.input_offset + entry.length)
{
- gold_assert(input_offset < entry.input_offset
- && input_offset + length <= entry.input_offset);
+ 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
+ else if (entry.input_offset + entry.length == input_offset_u
&& (output_offset == -1
? entry.output_offset == -1
- : entry.output_offset + entry.length == output_offset))
+ : entry.output_offset + entry.length == output_offset_u))
{
entry.length += length;
return;
bool
Object_merge_map::get_output_offset(const Merge_map* merge_map,
- unsigned int shndx, off_t input_offset,
- off_t *output_offset)
+ 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 || map->merge_map != merge_map)
+ if (map == NULL
+ || (merge_map != NULL && map->merge_map != merge_map))
return false;
if (!map->sorted)
gold_assert(p->input_offset <= input_offset);
}
- if (input_offset - p->input_offset >= p->length)
+ if (input_offset - p->input_offset
+ >= static_cast<section_offset_type>(p->length))
return false;
*output_offset = p->output_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 a merged
-// output section.
+// 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,
- off_t offset, off_t length, off_t output_offset)
+ 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)
// 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 output section. This returns
-// true if the mapping is known, false otherwise.
+// *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,
- off_t offset, off_t* output_offset) const
+ section_offset_type offset,
+ section_offset_type* output_offset) const
{
Object_merge_map* object_merge_map = object->merge_map();
if (object_merge_map == NULL)
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
bool
Output_merge_base::do_output_offset(const Relobj* object,
unsigned int shndx,
- off_t offset,
- off_t* poutput) const
+ 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.
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();
- uint64_t addsize = std::max(entsize, this->addralign());
+ 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)
bool
Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx)
{
- off_t len;
+ section_size_type len;
+ section_size_type uncompressed_size = 0;
+ unsigned char* uncompressed_data = NULL;
const unsigned char* p = object->section_contents(shndx, &len, false);
- uint64_t entsize = this->entsize();
+ if (object->section_is_compressed(shndx, &uncompressed_size))
+ {
+ uncompressed_data = new unsigned char[uncompressed_size];
+ if (!decompress_input_section(p, len, uncompressed_data,
+ uncompressed_size))
+ object->error(_("could not decompress section %s"),
+ object->section_name(shndx).c_str());
+ p = uncompressed_data;
+ len = uncompressed_size;
+ }
+
+ section_size_type entsize = convert_to_section_size_type(this->entsize());
if (len % entsize != 0)
- return false;
+ {
+ if (uncompressed_data != NULL)
+ delete[] uncompressed_data;
+ 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.
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);
+
+ if (uncompressed_data != NULL)
+ delete[] uncompressed_data;
+
return true;
}
{
// 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.
Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
unsigned int shndx)
{
- off_t len;
+ section_size_type len;
+ section_size_type uncompressed_size = 0;
+ unsigned char* uncompressed_data = NULL;
const unsigned char* pdata = object->section_contents(shndx, &len, false);
+ if (object->section_is_compressed(shndx, &uncompressed_size))
+ {
+ uncompressed_data = new unsigned char[uncompressed_size];
+ if (!decompress_input_section(pdata, len, uncompressed_data,
+ uncompressed_size))
+ object->error(_("could not decompress section %s"),
+ object->section_name(shndx).c_str());
+ pdata = uncompressed_data;
+ len = uncompressed_size;
+ }
+
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)
{
object->error(_("mergeable string section length not multiple of "
"character size"));
+ if (uncompressed_data != NULL)
+ delete[] uncompressed_data;
return false;
}
+ size_t count = 0;
+
+ Merged_strings_list* merged_strings_list =
+ new Merged_strings_list(object, shndx);
+ this->merged_strings_lists_.push_back(merged_strings_list);
+ Merged_strings& merged_strings = merged_strings_list->merged_strings;
+
// The index I is in bytes, not characters.
- off_t i = 0;
+ 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)
{
- // The length PLEN is in characters, not bytes.
- ++plen;
- if (i + plen * static_cast<off_t>(sizeof(Char_type)) >= 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;
+ this->stringpool_.add_with_length(p, pl - p, true, &key);
- off_t bytelen_with_null = (plen + 1) * sizeof(Char_type);
- this->merged_strings_.push_back(Merged_string(object, shndx, i, str,
- bytelen_with_null));
+ section_size_type bytelen_with_null = ((pl - p) + 1) * sizeof(Char_type);
+ merged_strings.push_back(Merged_string(i, key));
- p += plen + 1;
+ p = pl + 1;
i += bytelen_with_null;
+ ++count;
}
+ // Record the last offset in the input section so that we can
+ // compute the length of the last string.
+ merged_strings.push_back(Merged_string(i, 0));
+
+ this->input_count_ += count;
+
+ // For script processing, we keep the input sections.
+ if (this->keeps_input_sections())
+ record_input_section(object, shndx);
+
+ if (uncompressed_data != NULL)
+ delete[] uncompressed_data;
+
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>::set_final_data_size()
+section_size_type
+Output_merge_string<Char_type>::finalize_merged_data()
{
this->stringpool_.set_string_offsets();
- for (typename Merged_strings::const_iterator p =
- this->merged_strings_.begin();
- p != this->merged_strings_.end();
- ++p)
- this->add_mapping(p->object, p->shndx, p->offset, p->length,
- this->stringpool_.get_offset(p->string));
+ for (typename Merged_strings_lists::const_iterator l =
+ this->merged_strings_lists_.begin();
+ l != this->merged_strings_lists_.end();
+ ++l)
+ {
+ section_offset_type last_input_offset = 0;
+ section_offset_type last_output_offset = 0;
+ for (typename Merged_strings::const_iterator p =
+ (*l)->merged_strings.begin();
+ p != (*l)->merged_strings.end();
+ ++p)
+ {
+ section_size_type length = p->offset - last_input_offset;
+ if (length > 0)
+ this->add_mapping((*l)->object, (*l)->shndx, last_input_offset,
+ length, last_output_offset);
+ last_input_offset = p->offset;
+ if (p->stringpool_key != 0)
+ last_output_offset =
+ this->stringpool_.get_offset_from_key(p->stringpool_key);
+ }
+ delete *l;
+ }
- this->set_data_size(this->stringpool_.get_strtab_size());
+ // 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_lists_.clear();
- // Save some memory.
- 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.
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