// icf.cc -- Identical Code Folding.
//
-// Copyright (C) 2009-2016 Free Software Foundation, Inc.
+// Copyright (C) 2009-2017 Free Software Foundation, Inc.
// Written by Sriraman Tallam <tmsriram@google.com>.
// This file is part of gold.
}
}
+// For SHF_MERGE sections that use REL relocations, the addend is stored in
+// the text section at the relocation offset. Read the addend value given
+// the pointer to the addend in the text section and the addend size.
+// Update the addend value if a valid addend is found.
+// Parameters:
+// RELOC_ADDEND_PTR : Pointer to the addend in the text section.
+// ADDEND_SIZE : The size of the addend.
+// RELOC_ADDEND_VALUE : Pointer to the addend that is updated.
+
+inline void
+get_rel_addend(const unsigned char* reloc_addend_ptr,
+ const unsigned int addend_size,
+ uint64_t* reloc_addend_value)
+{
+ switch (addend_size)
+ {
+ case 0:
+ break;
+ case 1:
+ *reloc_addend_value =
+ read_from_pointer<8>(reloc_addend_ptr);
+ break;
+ case 2:
+ *reloc_addend_value =
+ read_from_pointer<16>(reloc_addend_ptr);
+ break;
+ case 4:
+ *reloc_addend_value =
+ read_from_pointer<32>(reloc_addend_ptr);
+ break;
+ case 8:
+ *reloc_addend_value =
+ read_from_pointer<64>(reloc_addend_ptr);
+ break;
+ default:
+ gold_unreachable();
+ }
+}
+
// This returns the buffer containing the section's contents, both
// text and relocs. Relocs are differentiated as those pointing to
// sections that could be folded and those that cannot. Only relocs
uint64_t entsize =
(it_v->first)->section_entsize(it_v->second);
long long offset = it_a->first;
-
- unsigned long long addend = it_a->second;
- // Ignoring the addend when it is a negative value. See the
- // comments in Merged_symbol_value::Value in object.h.
- if (addend < 0xffffff00)
- offset = offset + addend;
-
- // For SHT_REL relocation sections, the addend is stored in the
- // text section at the relocation offset.
- uint64_t reloc_addend_value = 0;
+ // Handle SHT_RELA and SHT_REL addends, only one of these
+ // addends exists.
+ // Get the SHT_RELA addend. For RELA relocations, we have
+ // the addend from the relocation.
+ uint64_t reloc_addend_value = it_a->second;
+
+ // Handle SHT_REL addends.
+ // For REL relocations, we need to fetch the addend from the
+ // section contents.
const unsigned char* reloc_addend_ptr =
contents + static_cast<unsigned long long>(*it_o);
- switch(*it_addend_size)
- {
- case 0:
- {
- break;
- }
- case 1:
- {
- reloc_addend_value =
- read_from_pointer<8>(reloc_addend_ptr);
- break;
- }
- case 2:
- {
- reloc_addend_value =
- read_from_pointer<16>(reloc_addend_ptr);
- break;
- }
- case 4:
- {
- reloc_addend_value =
- read_from_pointer<32>(reloc_addend_ptr);
- break;
- }
- case 8:
- {
- reloc_addend_value =
- read_from_pointer<64>(reloc_addend_ptr);
- break;
- }
- default:
- gold_unreachable();
- }
- offset = offset + reloc_addend_value;
+
+ // Update the addend value with the SHT_REL addend if
+ // available.
+ get_rel_addend(reloc_addend_ptr, *it_addend_size,
+ &reloc_addend_value);
+
+ // Ignore the addend when it is a negative value. See the
+ // comments in Merged_symbol_value::value in object.h.
+ if (reloc_addend_value < 0xffffff00)
+ offset = offset + reloc_addend_value;
section_size_type secn_len;
+
const unsigned char* str_contents =
(it_v->first)->section_contents(it_v->second,
&secn_len,
false) + offset;
+ gold_assert (offset < (long long) secn_len);
+
if ((secn_flags & elfcpp::SHF_STRINGS) != 0)
{
// String merge section.
}
else
{
- // Use the entsize to determine the length.
- buffer.append(reinterpret_cast<const
+ // Use the entsize to determine the length to copy.
+ uint64_t bufsize = entsize;
+ // If entsize is too big, copy all the remaining bytes.
+ if ((offset + entsize) > secn_len)
+ bufsize = secn_len - offset;
+ buffer.append(reinterpret_cast<const
char*>(str_contents),
- entsize);
+ bufsize);
}
buffer.append("@");
}
{
buffer.append("Contents = ");
buffer.append(reinterpret_cast<const char*>(contents), plen);
- // Store the section contents that dont change to avoid recomputing
+ // Store the section contents that don't change to avoid recomputing
// during the next call to this function.
(*section_contents)[section_num] = buffer;
}
std::vector<unsigned int>* num_tracked_relocs,
std::vector<unsigned int>* kept_section_id,
const std::vector<Section_id>& id_section,
+ const std::vector<uint64_t>& section_addraligns,
std::vector<bool>* is_secn_or_group_unique,
std::vector<std::string>* section_contents)
{
{
if ((*kept_section_id)[i] != i)
{
- // This section is already folded into something. See
- // if it should point to a different kept section.
- unsigned int kept_section = (*kept_section_id)[i];
- if (kept_section != (*kept_section_id)[kept_section])
- {
- (*kept_section_id)[i] = (*kept_section_id)[kept_section];
- }
+ // This section is already folded into something.
continue;
}
this_secn_contents = get_section_contents(false, secn, i, NULL,
this_secn_contents.c_str(),
this_secn_contents.length()) != 0)
continue;
- (*kept_section_id)[i] = kept_section;
+
+ // Check section alignment here.
+ // The section with the larger alignment requirement
+ // should be kept. We assume alignment can only be
+ // zero or positive integral powers of two.
+ uint64_t align_i = section_addraligns[i];
+ uint64_t align_kept = section_addraligns[kept_section];
+ if (align_i <= align_kept)
+ {
+ (*kept_section_id)[i] = kept_section;
+ }
+ else
+ {
+ (*kept_section_id)[kept_section] = i;
+ it->second = i;
+ full_section_contents[kept_section].swap(
+ full_section_contents[i]);
+ }
+
converged = false;
break;
}
(*is_secn_or_group_unique)[i] = true;
}
+ // If a section was folded into another section that was later folded
+ // again then the former has to be updated.
+ for (unsigned int i = 0; i < id_section.size(); i++)
+ {
+ // Find the end of the folding chain
+ unsigned int kept = i;
+ while ((*kept_section_id)[kept] != kept)
+ {
+ kept = (*kept_section_id)[kept];
+ }
+ // Update every element of the chain
+ unsigned int current = i;
+ while ((*kept_section_id)[current] != kept)
+ {
+ unsigned int next = (*kept_section_id)[current];
+ (*kept_section_id)[current] = kept;
+ current = next;
+ }
+ }
+
return converged;
}
{
unsigned int section_num = 0;
std::vector<unsigned int> num_tracked_relocs;
+ std::vector<uint64_t> section_addraligns;
std::vector<bool> is_secn_or_group_unique;
std::vector<std::string> section_contents;
const Target& target = parameters->target();
this->section_id_[Section_id(*p, i)] = section_num;
this->kept_section_id_.push_back(section_num);
num_tracked_relocs.push_back(0);
+ section_addraligns.push_back((*p)->section_addralign(i));
is_secn_or_group_unique.push_back(false);
section_contents.push_back("");
section_num++;
num_iterations++;
converged = match_sections(num_iterations, symtab,
&num_tracked_relocs, &this->kept_section_id_,
- this->id_section_, &is_secn_or_group_unique,
- §ion_contents);
+ this->id_section_, section_addraligns,
+ &is_secn_or_group_unique, §ion_contents);
}
if (parameters->options().print_icf_sections())
projects / deliverable / binutils-gdb.git / blobdiff