Add small library for writing of DWARF data.

Change-Id: Ifa77aec7584bfcdcc05ddb049c160be9b6dda7c5

1 files changed, 96 insertions, 0 deletions

diff --git a/compiler/dwarf/debug_frame_writer.h b/compiler/dwarf/debug_frame_writer.h
new file mode 100644
index 0000000..6de45f5
--- /dev/null
+++ b/compiler/dwarf/debug_frame_writer.h
@@ -0,0 +1,96 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#ifndef ART_COMPILER_DWARF_DEBUG_FRAME_WRITER_H_
+#define ART_COMPILER_DWARF_DEBUG_FRAME_WRITER_H_
+
+#include "debug_frame_opcode_writer.h"
+#include "dwarf.h"
+#include "writer.h"
+
+namespace art {
+namespace dwarf {
+
+// Writer for the .eh_frame section (which extends .debug_frame specification).
+template<typename Allocator = std::allocator<uint8_t>>
+class DebugFrameWriter FINAL : private Writer<Allocator> {
+ public:
+  void WriteCIE(Reg return_address_register,
+                const uint8_t* initial_opcodes,
+                int initial_opcodes_size) {
+    DCHECK(cie_header_start_ == ~0u);
+    cie_header_start_ = this->data()->size();
+    this->PushUint32(0);  // Length placeholder.
+    this->PushUint32(0);  // CIE id.
+    this->PushUint8(1);   // Version.
+    this->PushString("zR");
+    this->PushUleb128(DebugFrameOpCodeWriter<Allocator>::kCodeAlignmentFactor);
+    this->PushSleb128(DebugFrameOpCodeWriter<Allocator>::kDataAlignmentFactor);
+    this->PushUleb128(return_address_register.num());  // ubyte in DWARF2.
+    this->PushUleb128(1);  // z: Augmentation data size.
+    if (use_64bit_address_) {
+      this->PushUint8(0x04);  // R: ((DW_EH_PE_absptr << 4) | DW_EH_PE_udata8).
+    } else {
+      this->PushUint8(0x03);  // R: ((DW_EH_PE_absptr << 4) | DW_EH_PE_udata4).
+    }
+    this->PushData(initial_opcodes, initial_opcodes_size);
+    this->Pad(use_64bit_address_ ? 8 : 4);
+    this->UpdateUint32(cie_header_start_, this->data()->size() - cie_header_start_ - 4);
+  }
+
+  void WriteCIE(Reg return_address_register,
+                const DebugFrameOpCodeWriter<Allocator>& opcodes) {
+    WriteCIE(return_address_register, opcodes.data()->data(), opcodes.data()->size());
+  }
+
+  void WriteFDE(uint64_t initial_address,
+                uint64_t address_range,
+                const uint8_t* unwind_opcodes,
+                int unwind_opcodes_size) {
+    DCHECK(cie_header_start_ != ~0u);
+    size_t fde_header_start = this->data()->size();
+    this->PushUint32(0);  // Length placeholder.
+    this->PushUint32(this->data()->size() - cie_header_start_);  // 'CIE_pointer'
+    if (use_64bit_address_) {
+      this->PushUint64(initial_address);
+      this->PushUint64(address_range);
+    } else {
+      this->PushUint32(initial_address);
+      this->PushUint32(address_range);
+    }
+    this->PushUleb128(0);  // Augmentation data size.
+    this->PushData(unwind_opcodes, unwind_opcodes_size);
+    this->Pad(use_64bit_address_ ? 8 : 4);
+    this->UpdateUint32(fde_header_start, this->data()->size() - fde_header_start - 4);
+  }
+
+  DebugFrameWriter(std::vector<uint8_t, Allocator>* buffer, bool use_64bit_address)
+      : Writer<Allocator>(buffer),
+        use_64bit_address_(use_64bit_address),
+        cie_header_start_(~0u) {
+  }
+
+ private:
+  bool use_64bit_address_;
+  size_t cie_header_start_;
+
+  DISALLOW_COPY_AND_ASSIGN(DebugFrameWriter);
+};
+
+}  // namespace dwarf
+}  // namespace art
+
+#endif  // ART_COMPILER_DWARF_DEBUG_FRAME_WRITER_H_