Add support for only a .eh_frame.
Static executables only have a .eh_frame section and no .eh_frame_hdr
section. Add support for this by rearranging the class hierarchy and
creating a DwarfEhFrameWithHdr class and a DwarfEhFrame class to handle
the different cases.
Add new unit tests for DwarfEhFrame and for the new functionality.
Bug: 68820189
Test: Passes new unit tests, unwinds static executables.
Change-Id: I63d7cb8c52a686e96579a2266e18c0d06bbb6e63
diff --git a/libunwindstack/DwarfEhFrameWithHdr.cpp b/libunwindstack/DwarfEhFrameWithHdr.cpp
new file mode 100644
index 0000000..d8cbdf4
--- /dev/null
+++ b/libunwindstack/DwarfEhFrameWithHdr.cpp
@@ -0,0 +1,217 @@
+/*
+ * 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 <stdint.h>
+
+#include <unwindstack/DwarfStructs.h>
+#include <unwindstack/Memory.h>
+
+#include "Check.h"
+#include "DwarfEhFrameWithHdr.h"
+#include "DwarfError.h"
+
+namespace unwindstack {
+
+template <typename AddressType>
+bool DwarfEhFrameWithHdr<AddressType>::Init(uint64_t offset, uint64_t size) {
+ uint8_t data[4];
+
+ memory_.clear_func_offset();
+ memory_.clear_text_offset();
+ memory_.set_data_offset(offset);
+ memory_.set_cur_offset(offset);
+
+ // Read the first four bytes all at once.
+ if (!memory_.ReadBytes(data, 4)) {
+ last_error_ = DWARF_ERROR_MEMORY_INVALID;
+ return false;
+ }
+
+ version_ = data[0];
+ if (version_ != 1) {
+ // Unknown version.
+ last_error_ = DWARF_ERROR_UNSUPPORTED_VERSION;
+ return false;
+ }
+
+ ptr_encoding_ = data[1];
+ uint8_t fde_count_encoding = data[2];
+ table_encoding_ = data[3];
+ table_entry_size_ = memory_.template GetEncodedSize<AddressType>(table_encoding_);
+
+ memory_.set_pc_offset(memory_.cur_offset());
+ if (!memory_.template ReadEncodedValue<AddressType>(ptr_encoding_, &ptr_offset_)) {
+ last_error_ = DWARF_ERROR_MEMORY_INVALID;
+ return false;
+ }
+
+ memory_.set_pc_offset(memory_.cur_offset());
+ if (!memory_.template ReadEncodedValue<AddressType>(fde_count_encoding, &fde_count_)) {
+ last_error_ = DWARF_ERROR_MEMORY_INVALID;
+ return false;
+ }
+
+ entries_offset_ = memory_.cur_offset();
+ entries_end_ = offset + size;
+ entries_data_offset_ = offset;
+ cur_entries_offset_ = entries_offset_;
+
+ return true;
+}
+
+template <typename AddressType>
+const DwarfFde* DwarfEhFrameWithHdr<AddressType>::GetFdeFromIndex(size_t index) {
+ const FdeInfo* info = GetFdeInfoFromIndex(index);
+ if (info == nullptr) {
+ return nullptr;
+ }
+ return this->GetFdeFromOffset(info->offset);
+}
+
+template <typename AddressType>
+const typename DwarfEhFrameWithHdr<AddressType>::FdeInfo*
+DwarfEhFrameWithHdr<AddressType>::GetFdeInfoFromIndex(size_t index) {
+ auto entry = fde_info_.find(index);
+ if (entry != fde_info_.end()) {
+ return &fde_info_[index];
+ }
+ FdeInfo* info = &fde_info_[index];
+
+ memory_.set_data_offset(entries_data_offset_);
+ memory_.set_cur_offset(entries_offset_ + 2 * index * table_entry_size_);
+ memory_.set_pc_offset(memory_.cur_offset());
+ uint64_t value;
+ if (!memory_.template ReadEncodedValue<AddressType>(table_encoding_, &value) ||
+ !memory_.template ReadEncodedValue<AddressType>(table_encoding_, &info->offset)) {
+ last_error_ = DWARF_ERROR_MEMORY_INVALID;
+ fde_info_.erase(index);
+ return nullptr;
+ }
+ info->pc = value + 4;
+ return info;
+}
+
+template <typename AddressType>
+bool DwarfEhFrameWithHdr<AddressType>::GetFdeOffsetBinary(uint64_t pc, uint64_t* fde_offset,
+ uint64_t total_entries) {
+ CHECK(fde_count_ > 0);
+ CHECK(total_entries <= fde_count_);
+
+ size_t first = 0;
+ size_t last = total_entries;
+ while (first < last) {
+ size_t current = (first + last) / 2;
+ const FdeInfo* info = GetFdeInfoFromIndex(current);
+ if (pc == info->pc) {
+ *fde_offset = info->offset;
+ return true;
+ }
+ if (pc < info->pc) {
+ last = current;
+ } else {
+ first = current + 1;
+ }
+ }
+ if (last != 0) {
+ const FdeInfo* info = GetFdeInfoFromIndex(last - 1);
+ *fde_offset = info->offset;
+ return true;
+ }
+ return false;
+}
+
+template <typename AddressType>
+bool DwarfEhFrameWithHdr<AddressType>::GetFdeOffsetSequential(uint64_t pc, uint64_t* fde_offset) {
+ CHECK(fde_count_ != 0);
+ last_error_ = DWARF_ERROR_NONE;
+ // We can do a binary search if the pc is in the range of the elements
+ // that have already been cached.
+ if (!fde_info_.empty()) {
+ const FdeInfo* info = &fde_info_[fde_info_.size() - 1];
+ if (pc >= info->pc) {
+ *fde_offset = info->offset;
+ return true;
+ }
+ if (pc < info->pc) {
+ return GetFdeOffsetBinary(pc, fde_offset, fde_info_.size());
+ }
+ }
+
+ if (cur_entries_offset_ == 0) {
+ // All entries read, or error encountered.
+ return false;
+ }
+
+ memory_.set_data_offset(entries_data_offset_);
+ memory_.set_cur_offset(cur_entries_offset_);
+ cur_entries_offset_ = 0;
+
+ FdeInfo* prev_info = nullptr;
+ for (size_t current = fde_info_.size();
+ current < fde_count_ && memory_.cur_offset() < entries_end_; current++) {
+ memory_.set_pc_offset(memory_.cur_offset());
+ uint64_t value;
+ if (!memory_.template ReadEncodedValue<AddressType>(table_encoding_, &value)) {
+ last_error_ = DWARF_ERROR_MEMORY_INVALID;
+ return false;
+ }
+
+ FdeInfo* info = &fde_info_[current];
+ if (!memory_.template ReadEncodedValue<AddressType>(table_encoding_, &info->offset)) {
+ fde_info_.erase(current);
+ last_error_ = DWARF_ERROR_MEMORY_INVALID;
+ return false;
+ }
+ info->pc = value + 4;
+
+ if (pc < info->pc) {
+ if (prev_info == nullptr) {
+ return false;
+ }
+ cur_entries_offset_ = memory_.cur_offset();
+ *fde_offset = prev_info->offset;
+ return true;
+ }
+ prev_info = info;
+ }
+
+ if (fde_count_ == fde_info_.size() && pc >= prev_info->pc) {
+ *fde_offset = prev_info->offset;
+ return true;
+ }
+ return false;
+}
+
+template <typename AddressType>
+bool DwarfEhFrameWithHdr<AddressType>::GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) {
+ if (fde_count_ == 0) {
+ return false;
+ }
+
+ if (table_entry_size_ > 0) {
+ // Do a binary search since the size of each table entry is fixed.
+ return GetFdeOffsetBinary(pc, fde_offset, fde_count_);
+ } else {
+ // Do a sequential search since each table entry size is variable.
+ return GetFdeOffsetSequential(pc, fde_offset);
+ }
+}
+
+// Explicitly instantiate DwarfEhFrameWithHdr
+template class DwarfEhFrameWithHdr<uint32_t>;
+template class DwarfEhFrameWithHdr<uint64_t>;
+
+} // namespace unwindstack