Add Symbols parsing.
Bug: 23762183
Test: New unit tests pass.
Change-Id: Ib67fee879120b5e82889076a0f7221dc429ac140
diff --git a/libunwindstack/Symbols.cpp b/libunwindstack/Symbols.cpp
new file mode 100644
index 0000000..86c1233
--- /dev/null
+++ b/libunwindstack/Symbols.cpp
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <elf.h>
+#include <stdint.h>
+
+#include <string>
+
+#include "Memory.h"
+#include "Symbols.h"
+
+Symbols::Symbols(uint64_t offset, uint64_t size, uint64_t entry_size, uint64_t str_offset,
+ uint64_t str_size)
+ : cur_offset_(offset),
+ offset_(offset),
+ end_(offset + size),
+ entry_size_(entry_size),
+ str_offset_(str_offset),
+ str_end_(str_offset_ + str_size) {}
+
+const Symbols::Info* Symbols::GetInfoFromCache(uint64_t addr) {
+ // Binary search the table.
+ size_t first = 0;
+ size_t last = symbols_.size();
+ while (first < last) {
+ size_t current = first + (last - first) / 2;
+ const Info* info = &symbols_[current];
+ if (addr < info->start_offset) {
+ last = current;
+ } else if (addr < info->end_offset) {
+ return info;
+ } else {
+ first = current + 1;
+ }
+ }
+ return nullptr;
+}
+
+template <typename SymType>
+bool Symbols::GetName(uint64_t addr, uint64_t load_bias, Memory* elf_memory, std::string* name,
+ uint64_t* func_offset) {
+ addr += load_bias;
+
+ if (symbols_.size() != 0) {
+ const Info* info = GetInfoFromCache(addr);
+ if (info) {
+ assert(addr >= info->start_offset && addr <= info->end_offset);
+ *func_offset = addr - info->start_offset;
+ return elf_memory->ReadString(info->str_offset, name, str_end_ - info->str_offset);
+ }
+ }
+
+ bool symbol_added = false;
+ bool return_value = false;
+ while (cur_offset_ + entry_size_ <= end_) {
+ SymType entry;
+ if (!elf_memory->Read(cur_offset_, &entry, sizeof(entry))) {
+ // Stop all processing, something looks like it is corrupted.
+ cur_offset_ = UINT64_MAX;
+ return false;
+ }
+ cur_offset_ += entry_size_;
+
+ if (entry.st_shndx != SHN_UNDEF && ELF32_ST_TYPE(entry.st_info) == STT_FUNC) {
+ // Treat st_value as virtual address.
+ uint64_t start_offset = entry.st_value;
+ if (entry.st_shndx != SHN_ABS) {
+ start_offset += load_bias;
+ }
+ uint64_t end_offset = start_offset + entry.st_size;
+
+ // Cache the value.
+ symbols_.emplace_back(start_offset, end_offset, str_offset_ + entry.st_name);
+ symbol_added = true;
+
+ if (addr >= start_offset && addr < end_offset) {
+ *func_offset = addr - start_offset;
+ uint64_t offset = str_offset_ + entry.st_name;
+ if (offset < str_end_) {
+ return_value = elf_memory->ReadString(offset, name, str_end_ - offset);
+ }
+ break;
+ }
+ }
+ }
+
+ if (symbol_added) {
+ std::sort(symbols_.begin(), symbols_.end(),
+ [](const Info& a, const Info& b) { return a.start_offset < b.start_offset; });
+ }
+ return return_value;
+}
+
+// Instantiate all of the needed template functions.
+template bool Symbols::GetName<Elf32_Sym>(uint64_t, uint64_t, Memory*, std::string*, uint64_t*);
+template bool Symbols::GetName<Elf64_Sym>(uint64_t, uint64_t, Memory*, std::string*, uint64_t*);