From 3be83b7b225b4509a49b88b8cfb63be0f1a2f79b Mon Sep 17 00:00:00 2001
From: Jacob Lewallen <jlewallen@gmail.com>
Date: Mon, 24 Jun 2019 19:53:15 -0700
Subject: [PATCH] Fix performance issue parsing relocations.
Uses a map to track added relocations.
---
src/ELF/Parser.tcc | 49 ++++++++++++++++++++++++++++++++++------------
1 file changed, 36 insertions(+), 13 deletions(-)
diff --git a/src/ELF/Parser.tcc b/src/ELF/Parser.tcc
index 457fc38..279910f 100644
--- a/src/ELF/Parser.tcc
+++ b/src/ELF/Parser.tcc
@@ -18,6 +18,7 @@
#include "LIEF/utils.hpp"
+#include "LIEF/ELF/hash.hpp"
#include "LIEF/ELF/DynamicEntryFlags.hpp"
#include "Object.tcc"
@@ -1339,6 +1340,29 @@ void Parser::parse_pltgot_relocations(uint64_t offset, uint64_t size) {
}
}
+struct RelocationKey {
+ uint64_t address;
+ uint32_t type;
+ int64_t addend;
+ size_t symbol;
+
+ bool operator==(const RelocationKey &o) const {
+ return address == o.address && type == o.type && addend == o.addend && symbol == o.symbol;
+ }
+
+ bool operator<(const RelocationKey &o) const {
+ return address < o.address || (address == o.address && type < o.type) ||
+ ((address == o.address && type == o.type) || addend < o .addend) ||
+ ((address == o.address && type == o.type && addend == o.addend) && symbol < o.symbol);
+ }
+
+ bool operator>(const RelocationKey &o) const {
+ return address > o.address || (address == o.address && type > o.type) ||
+ ((address == o.address && type == o.type) || addend > o.addend) ||
+ ((address == o.address && type == o.type && addend == o.addend) && symbol > o.symbol);
+ }
+};
+
template<typename ELF_T, typename REL_T>
void Parser::parse_section_relocations(Section const& section) {
using Elf_Rel = typename ELF_T::Elf_Rel;
@@ -1370,6 +1394,8 @@ void Parser::parse_section_relocations(Section const& section) {
uint32_t nb_entries = static_cast<uint32_t>(section.size() / sizeof(REL_T));
nb_entries = std::min<uint32_t>(nb_entries, Parser::NB_MAX_RELOCATIONS);
+ std::map<RelocationKey, Relocation*> map;
+
this->stream_->setpos(offset_relocations);
for (uint32_t i = 0; i < nb_entries; ++i) {
if (not this->stream_->can_read<REL_T>()) {
@@ -1392,19 +1418,16 @@ void Parser::parse_section_relocations(Section const& section) {
reloc->symbol_ = this->binary_->static_symbols_[idx];
}
- // TODO: BAD CODE!!!!
- if (std::find_if(
- std::begin(this->binary_->relocations_),
- std::end(this->binary_->relocations_),
- [&reloc] (const Relocation* r) {
- bool is_same = r->address() == reloc->address() and
- r->type() == reloc->type() and
- r->addend() == reloc->addend();
- if(r->has_symbol())
- is_same &= reloc->has_symbol() and reloc->symbol() == r->symbol();
- return is_same;
- }) == std::end(this->binary_->relocations_)) {
- this->binary_->relocations_.push_back(reloc.release());
+ RelocationKey k = {
+ reloc->address(),
+ reloc->type(),
+ reloc->addend(),
+ reloc->has_symbol() ? LIEF::Hash::hash(reloc->symbol()) : 0
+ };
+
+ if (map[k] == nullptr) {
+ auto released = map[k] = reloc.release();
+ this->binary_->relocations_.push_back(released);
}
}
}