Add DwarfMemory class.
Bug: 23762183
Test: Passes new unit tests.
Change-Id: I80293af0b5a8a042195c37a06d64082d2f7c781a
diff --git a/libunwindstack/DwarfMemory.cpp b/libunwindstack/DwarfMemory.cpp
new file mode 100644
index 0000000..11806ea
--- /dev/null
+++ b/libunwindstack/DwarfMemory.cpp
@@ -0,0 +1,248 @@
+/*
+ * 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 <stdint.h>
+
+#include <string>
+
+#include "DwarfEncoding.h"
+#include "DwarfMemory.h"
+#include "Memory.h"
+
+bool DwarfMemory::ReadBytes(void* dst, size_t num_bytes) {
+ if (!memory_->Read(cur_offset_, dst, num_bytes)) {
+ return false;
+ }
+ cur_offset_ += num_bytes;
+ return true;
+}
+
+template <typename SignedType>
+bool DwarfMemory::ReadSigned(uint64_t* value) {
+ SignedType signed_value;
+ if (!ReadBytes(&signed_value, sizeof(SignedType))) {
+ return false;
+ }
+ *value = static_cast<int64_t>(signed_value);
+ return true;
+}
+
+bool DwarfMemory::ReadULEB128(uint64_t* value) {
+ uint64_t cur_value = 0;
+ uint64_t shift = 0;
+ uint8_t byte;
+ do {
+ if (!ReadBytes(&byte, 1)) {
+ return false;
+ }
+ cur_value += static_cast<uint64_t>(byte & 0x7f) << shift;
+ shift += 7;
+ } while (byte & 0x80);
+ *value = cur_value;
+ return true;
+}
+
+bool DwarfMemory::ReadSLEB128(int64_t* value) {
+ uint64_t cur_value = 0;
+ uint64_t shift = 0;
+ uint8_t byte;
+ do {
+ if (!ReadBytes(&byte, 1)) {
+ return false;
+ }
+ cur_value += static_cast<uint64_t>(byte & 0x7f) << shift;
+ shift += 7;
+ } while (byte & 0x80);
+ if (byte & 0x40) {
+ // Negative value, need to sign extend.
+ cur_value |= static_cast<uint64_t>(-1) << shift;
+ }
+ *value = static_cast<int64_t>(cur_value);
+ return true;
+}
+
+template <typename AddressType>
+size_t DwarfMemory::GetEncodedSize(uint8_t encoding) {
+ switch (encoding & 0x0f) {
+ case DW_EH_PE_absptr:
+ return sizeof(AddressType);
+ case DW_EH_PE_udata1:
+ case DW_EH_PE_sdata1:
+ return 1;
+ case DW_EH_PE_udata2:
+ case DW_EH_PE_sdata2:
+ return 2;
+ case DW_EH_PE_udata4:
+ case DW_EH_PE_sdata4:
+ return 4;
+ case DW_EH_PE_udata8:
+ case DW_EH_PE_sdata8:
+ return 8;
+ case DW_EH_PE_uleb128:
+ case DW_EH_PE_sleb128:
+ default:
+ return 0;
+ }
+}
+
+bool DwarfMemory::AdjustEncodedValue(uint8_t encoding, uint64_t* value) {
+ assert((encoding & 0x0f) == 0);
+ assert(encoding != DW_EH_PE_aligned);
+
+ // Handle the encoding.
+ switch (encoding) {
+ case DW_EH_PE_absptr:
+ // Nothing to do.
+ break;
+ case DW_EH_PE_pcrel:
+ if (pc_offset_ == static_cast<uint64_t>(-1)) {
+ // Unsupported encoding.
+ return false;
+ }
+ *value += pc_offset_;
+ break;
+ case DW_EH_PE_textrel:
+ if (text_offset_ == static_cast<uint64_t>(-1)) {
+ // Unsupported encoding.
+ return false;
+ }
+ *value += text_offset_;
+ break;
+ case DW_EH_PE_datarel:
+ if (data_offset_ == static_cast<uint64_t>(-1)) {
+ // Unsupported encoding.
+ return false;
+ }
+ *value += data_offset_;
+ break;
+ case DW_EH_PE_funcrel:
+ if (func_offset_ == static_cast<uint64_t>(-1)) {
+ // Unsupported encoding.
+ return false;
+ }
+ *value += func_offset_;
+ break;
+ default:
+ return false;
+ }
+
+ return true;
+}
+
+template <typename AddressType>
+bool DwarfMemory::ReadEncodedValue(uint8_t encoding, uint64_t* value) {
+ if (encoding == DW_EH_PE_omit) {
+ *value = 0;
+ return true;
+ } else if (encoding == DW_EH_PE_aligned) {
+ if (__builtin_add_overflow(cur_offset_, sizeof(AddressType) - 1, &cur_offset_)) {
+ return false;
+ }
+ cur_offset_ &= -sizeof(AddressType);
+
+ if (sizeof(AddressType) != sizeof(uint64_t)) {
+ *value = 0;
+ }
+ return ReadBytes(value, sizeof(AddressType));
+ }
+
+ // Get the data.
+ switch (encoding & 0x0f) {
+ case DW_EH_PE_absptr:
+ if (sizeof(AddressType) != sizeof(uint64_t)) {
+ *value = 0;
+ }
+ if (!ReadBytes(value, sizeof(AddressType))) {
+ return false;
+ }
+ break;
+ case DW_EH_PE_uleb128:
+ if (!ReadULEB128(value)) {
+ return false;
+ }
+ break;
+ case DW_EH_PE_sleb128:
+ int64_t signed_value;
+ if (!ReadSLEB128(&signed_value)) {
+ return false;
+ }
+ *value = static_cast<uint64_t>(signed_value);
+ break;
+ case DW_EH_PE_udata1: {
+ uint8_t value8;
+ if (!ReadBytes(&value8, 1)) {
+ return false;
+ }
+ *value = value8;
+ } break;
+ case DW_EH_PE_sdata1:
+ if (!ReadSigned<int8_t>(value)) {
+ return false;
+ }
+ break;
+ case DW_EH_PE_udata2: {
+ uint16_t value16;
+ if (!ReadBytes(&value16, 2)) {
+ return false;
+ }
+ *value = value16;
+ } break;
+ case DW_EH_PE_sdata2:
+ if (!ReadSigned<int16_t>(value)) {
+ return false;
+ }
+ break;
+ case DW_EH_PE_udata4: {
+ uint32_t value32;
+ if (!ReadBytes(&value32, 4)) {
+ return false;
+ }
+ *value = value32;
+ } break;
+ case DW_EH_PE_sdata4:
+ if (!ReadSigned<int32_t>(value)) {
+ return false;
+ }
+ break;
+ case DW_EH_PE_udata8:
+ if (!ReadBytes(value, sizeof(uint64_t))) {
+ return false;
+ }
+ break;
+ case DW_EH_PE_sdata8:
+ if (!ReadSigned<int64_t>(value)) {
+ return false;
+ }
+ break;
+ default:
+ return false;
+ }
+
+ return AdjustEncodedValue(encoding & 0xf0, value);
+}
+
+// Instantiate all of the needed template functions.
+template bool DwarfMemory::ReadSigned<int8_t>(uint64_t*);
+template bool DwarfMemory::ReadSigned<int16_t>(uint64_t*);
+template bool DwarfMemory::ReadSigned<int32_t>(uint64_t*);
+template bool DwarfMemory::ReadSigned<int64_t>(uint64_t*);
+
+template size_t DwarfMemory::GetEncodedSize<uint32_t>(uint8_t);
+template size_t DwarfMemory::GetEncodedSize<uint64_t>(uint8_t);
+
+template bool DwarfMemory::ReadEncodedValue<uint32_t>(uint8_t, uint64_t*);
+template bool DwarfMemory::ReadEncodedValue<uint64_t>(uint8_t, uint64_t*);