Add support for the new unwind method.
Also add a comment to the GetElf function to indicate that it never returns
nullptr.
Also needed to add this library to the a million and one places that the vndk
has hard-coded this data.
Bug: 23762183
Test: Built, nothing uses the new code.
Test: However, I did run backtrace_test using this code, and all tests pass.
Change-Id: Ib270665dcb7a7607075e36d88be76dbde6e2faa8
(cherry picked from commit dc4104b720c7fd2014ccfa9fa621d02df58a43c4)
diff --git a/libbacktrace/UnwindStack.h b/libbacktrace/UnwindStack.h
new file mode 100644
index 0000000..32d1f51
--- /dev/null
+++ b/libbacktrace/UnwindStack.h
@@ -0,0 +1,56 @@
+/*
+ * 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.
+ */
+
+#ifndef _LIBBACKTRACE_UNWIND_STACK_H
+#define _LIBBACKTRACE_UNWIND_STACK_H
+
+#include <stdint.h>
+
+#include <string>
+
+#include <backtrace/BacktraceMap.h>
+#include <unwindstack/Memory.h>
+
+#include "BacktraceCurrent.h"
+#include "BacktracePtrace.h"
+
+class UnwindStackCurrent : public BacktraceCurrent {
+ public:
+ UnwindStackCurrent(pid_t pid, pid_t tid, BacktraceMap* map);
+ virtual ~UnwindStackCurrent() = default;
+
+ std::string GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) override;
+
+ bool UnwindFromContext(size_t num_ignore_frames, ucontext_t* ucontext) override;
+
+ private:
+ std::unique_ptr<unwindstack::Memory> memory_;
+};
+
+class UnwindStackPtrace : public BacktracePtrace {
+ public:
+ UnwindStackPtrace(pid_t pid, pid_t tid, BacktraceMap* map);
+ virtual ~UnwindStackPtrace() = default;
+
+ bool Unwind(size_t num_ignore_frames, ucontext_t* context) override;
+
+ std::string GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset);
+
+ private:
+ std::unique_ptr<unwindstack::Memory> memory_;
+};
+
+#endif // _LIBBACKTRACE_UNWIND_STACK_H