Update the Unwinder object and add tests.

Changes:
- Remove unused GetReturnAddressFromDefault function and tests.
- Modify the unwinder to stop when a pc/sp in a device map.
- Modify the unwinder to skip initial frames based on map names.
- Unit tests that exercise all of the paths in the unwinder code.
- Move the test Elf/ElfInterface objects into their own file.
- Update RegsFake to handle extra cases.
- Modify libbacktrace code to use this unwinder.

The new unwinder does not implement the ignore frame functionality since
this is not used very often and is better implemented using a skip frames
in named libraries functionality.

Test: Ran new unit tests, ran backtrace tests.
Change-Id: Ifd65e9acd66ac5e2d0e04bd32a9ad870b54610ff
diff --git a/libunwindstack/tests/UnwinderTest.cpp b/libunwindstack/tests/UnwinderTest.cpp
new file mode 100644
index 0000000..4d0366c
--- /dev/null
+++ b/libunwindstack/tests/UnwinderTest.cpp
@@ -0,0 +1,576 @@
+/*
+ * 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 <elf.h>
+#include <stdint.h>
+#include <sys/mman.h>
+
+#include <memory>
+#include <set>
+#include <string>
+
+#include <gtest/gtest.h>
+
+#include <unwindstack/Elf.h>
+#include <unwindstack/Maps.h>
+#include <unwindstack/Memory.h>
+#include <unwindstack/Regs.h>
+#include <unwindstack/Unwinder.h>
+
+#include "ElfFake.h"
+#include "MemoryFake.h"
+#include "RegsFake.h"
+
+namespace unwindstack {
+
+class MapsFake : public Maps {
+ public:
+  MapsFake() = default;
+  virtual ~MapsFake() = default;
+
+  bool Parse() { return true; }
+
+  void FakeClear() { maps_.clear(); }
+
+  void FakeAddMapInfo(const MapInfo& map_info) { maps_.push_back(map_info); }
+};
+
+class UnwinderTest : public ::testing::Test {
+ protected:
+  static void SetUpTestCase() {
+    maps_.FakeClear();
+    MapInfo info;
+    info.name = "/system/fake/libc.so";
+    info.start = 0x1000;
+    info.end = 0x8000;
+    info.offset = 0;
+    info.flags = PROT_READ | PROT_WRITE;
+    ElfFake* elf = new ElfFake(nullptr);
+    info.elf = elf;
+    elf->FakeSetInterface(new ElfInterfaceFake(nullptr));
+    info.elf_offset = 0;
+    maps_.FakeAddMapInfo(info);
+
+    info.name = "[stack]";
+    info.start = 0x10000;
+    info.end = 0x12000;
+    info.flags = PROT_READ | PROT_WRITE;
+    info.elf = nullptr;
+    maps_.FakeAddMapInfo(info);
+
+    info.name = "/dev/fake_device";
+    info.start = 0x13000;
+    info.end = 0x15000;
+    info.flags = PROT_READ | PROT_WRITE | MAPS_FLAGS_DEVICE_MAP;
+    info.elf = nullptr;
+    maps_.FakeAddMapInfo(info);
+
+    info.name = "/system/fake/libunwind.so";
+    info.start = 0x20000;
+    info.end = 0x22000;
+    info.flags = PROT_READ | PROT_WRITE;
+    elf = new ElfFake(nullptr);
+    info.elf = elf;
+    elf->FakeSetInterface(new ElfInterfaceFake(nullptr));
+    maps_.FakeAddMapInfo(info);
+
+    info.name = "/fake/libanother.so";
+    info.start = 0x23000;
+    info.end = 0x24000;
+    info.flags = PROT_READ | PROT_WRITE;
+    elf = new ElfFake(nullptr);
+    info.elf = elf;
+    elf->FakeSetInterface(new ElfInterfaceFake(nullptr));
+    maps_.FakeAddMapInfo(info);
+  }
+
+  void SetUp() override {
+    ElfInterfaceFake::FakeClear();
+    regs_.FakeSetMachineType(EM_ARM);
+  }
+
+  static MapsFake maps_;
+  static RegsFake regs_;
+  static std::shared_ptr<Memory> process_memory_;
+};
+
+MapsFake UnwinderTest::maps_;
+RegsFake UnwinderTest::regs_(5, 0);
+std::shared_ptr<Memory> UnwinderTest::process_memory_(nullptr);
+
+TEST_F(UnwinderTest, multiple_frames) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame2", 2));
+
+  regs_.FakeSetPc(0x1000);
+  regs_.FakeSetSp(0x10000);
+  ElfInterfaceFake::FakePushStepData(StepData(0x1102, 0x10010, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x1202, 0x10020, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0, 0, true));
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(3U, unwinder.NumFrames());
+
+  auto* frame = &unwinder.frames()[0];
+  EXPECT_EQ(0U, frame->num);
+  EXPECT_EQ(0U, frame->rel_pc);
+  EXPECT_EQ(0x1000U, frame->pc);
+  EXPECT_EQ(0x10000U, frame->sp);
+  EXPECT_EQ("Frame0", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libc.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x1000U, frame->map_start);
+  EXPECT_EQ(0x8000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+
+  frame = &unwinder.frames()[1];
+  EXPECT_EQ(1U, frame->num);
+  EXPECT_EQ(0x100U, frame->rel_pc);
+  EXPECT_EQ(0x1100U, frame->pc);
+  EXPECT_EQ(0x10010U, frame->sp);
+  EXPECT_EQ("Frame1", frame->function_name);
+  EXPECT_EQ(1U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libc.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x1000U, frame->map_start);
+  EXPECT_EQ(0x8000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+
+  frame = &unwinder.frames()[2];
+  EXPECT_EQ(2U, frame->num);
+  EXPECT_EQ(0x200U, frame->rel_pc);
+  EXPECT_EQ(0x1200U, frame->pc);
+  EXPECT_EQ(0x10020U, frame->sp);
+  EXPECT_EQ("Frame2", frame->function_name);
+  EXPECT_EQ(2U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libc.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x1000U, frame->map_start);
+  EXPECT_EQ(0x8000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+}
+
+// Verify that no attempt to continue after the step indicates it is done.
+TEST_F(UnwinderTest, no_frames_after_finished) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame2", 2));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame3", 3));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame4", 4));
+
+  regs_.FakeSetPc(0x1000);
+  regs_.FakeSetSp(0x10000);
+  ElfInterfaceFake::FakePushStepData(StepData(0x1000, 0x10000, true));
+  ElfInterfaceFake::FakePushStepData(StepData(0x1102, 0x10010, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x1202, 0x10020, false));
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(1U, unwinder.NumFrames());
+
+  auto* frame = &unwinder.frames()[0];
+  EXPECT_EQ(0U, frame->num);
+  EXPECT_EQ(0U, frame->rel_pc);
+  EXPECT_EQ(0x1000U, frame->pc);
+  EXPECT_EQ(0x10000U, frame->sp);
+  EXPECT_EQ("Frame0", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libc.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x1000U, frame->map_start);
+  EXPECT_EQ(0x8000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+}
+
+// Verify the maximum frames to save.
+TEST_F(UnwinderTest, max_frames) {
+  for (size_t i = 0; i < 30; i++) {
+    ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame" + std::to_string(i), i));
+    ElfInterfaceFake::FakePushStepData(StepData(0x1102 + i * 0x100, 0x10010 + i * 0x10, false));
+  }
+
+  regs_.FakeSetPc(0x1000);
+  regs_.FakeSetSp(0x10000);
+
+  Unwinder unwinder(20, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(20U, unwinder.NumFrames());
+
+  for (size_t i = 0; i < 20; i++) {
+    auto* frame = &unwinder.frames()[i];
+    EXPECT_EQ(i, frame->num);
+    EXPECT_EQ(i * 0x100, frame->rel_pc) << "Failed at frame " << i;
+    EXPECT_EQ(0x1000 + i * 0x100, frame->pc) << "Failed at frame " << i;
+    EXPECT_EQ(0x10000 + 0x10 * i, frame->sp) << "Failed at frame " << i;
+    EXPECT_EQ("Frame" + std::to_string(i), frame->function_name) << "Failed at frame " << i;
+    EXPECT_EQ(i, frame->function_offset) << "Failed at frame " << i;
+    EXPECT_EQ("/system/fake/libc.so", frame->map_name) << "Failed at frame " << i;
+    EXPECT_EQ(0U, frame->map_offset) << "Failed at frame " << i;
+    EXPECT_EQ(0x1000U, frame->map_start) << "Failed at frame " << i;
+    EXPECT_EQ(0x8000U, frame->map_end) << "Failed at frame " << i;
+    EXPECT_EQ(0U, frame->map_load_bias) << "Failed at frame " << i;
+    EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags) << "Failed at frame " << i;
+  }
+}
+
+// Verify that initial map names frames are removed.
+TEST_F(UnwinderTest, verify_frames_skipped) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame2", 2));
+
+  regs_.FakeSetPc(0x20000);
+  regs_.FakeSetSp(0x10000);
+  ElfInterfaceFake::FakePushStepData(StepData(0x23002, 0x10010, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x23102, 0x10020, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x20002, 0x10030, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x21002, 0x10040, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x1002, 0x10050, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x21002, 0x10060, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x23002, 0x10070, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0, 0, true));
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  std::set<std::string> skip_set{"libunwind.so", "libanother.so"};
+  unwinder.Unwind(&skip_set);
+
+  ASSERT_EQ(3U, unwinder.NumFrames());
+
+  auto* frame = &unwinder.frames()[0];
+  EXPECT_EQ(0U, frame->num);
+  EXPECT_EQ(0U, frame->rel_pc);
+  EXPECT_EQ(0x1000U, frame->pc);
+  EXPECT_EQ(0x10050U, frame->sp);
+  EXPECT_EQ("Frame0", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libc.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x1000U, frame->map_start);
+  EXPECT_EQ(0x8000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+
+  frame = &unwinder.frames()[1];
+  EXPECT_EQ(1U, frame->num);
+  EXPECT_EQ(0x1000U, frame->rel_pc);
+  EXPECT_EQ(0x21000U, frame->pc);
+  EXPECT_EQ(0x10060U, frame->sp);
+  EXPECT_EQ("Frame1", frame->function_name);
+  EXPECT_EQ(1U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libunwind.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x20000U, frame->map_start);
+  EXPECT_EQ(0x22000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+
+  frame = &unwinder.frames()[2];
+  EXPECT_EQ(2U, frame->num);
+  EXPECT_EQ(0U, frame->rel_pc);
+  EXPECT_EQ(0x23000U, frame->pc);
+  EXPECT_EQ(0x10070U, frame->sp);
+  EXPECT_EQ("Frame2", frame->function_name);
+  EXPECT_EQ(2U, frame->function_offset);
+  EXPECT_EQ("/fake/libanother.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x23000U, frame->map_start);
+  EXPECT_EQ(0x24000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+}
+
+// Verify SP in a non-existant map is okay.
+TEST_F(UnwinderTest, sp_not_in_map) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+
+  regs_.FakeSetPc(0x1000);
+  regs_.FakeSetSp(0x53000);
+  ElfInterfaceFake::FakePushStepData(StepData(0x21002, 0x50020, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0, 0, true));
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(2U, unwinder.NumFrames());
+
+  auto* frame = &unwinder.frames()[0];
+  EXPECT_EQ(0U, frame->num);
+  EXPECT_EQ(0U, frame->rel_pc);
+  EXPECT_EQ(0x1000U, frame->pc);
+  EXPECT_EQ(0x53000U, frame->sp);
+  EXPECT_EQ("Frame0", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libc.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x1000U, frame->map_start);
+  EXPECT_EQ(0x8000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+
+  frame = &unwinder.frames()[1];
+  EXPECT_EQ(1U, frame->num);
+  EXPECT_EQ(0x1000U, frame->rel_pc);
+  EXPECT_EQ(0x21000U, frame->pc);
+  EXPECT_EQ(0x50020U, frame->sp);
+  EXPECT_EQ("Frame1", frame->function_name);
+  EXPECT_EQ(1U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libunwind.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x20000U, frame->map_start);
+  EXPECT_EQ(0x22000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+}
+
+// Verify PC in a device stops the unwind.
+TEST_F(UnwinderTest, pc_in_device_stops_unwind) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame2", 2));
+
+  regs_.FakeSetPc(0x13000);
+  regs_.FakeSetSp(0x10000);
+  ElfInterfaceFake::FakePushStepData(StepData(0x23002, 0x10010, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x23102, 0x10020, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0, 0, true));
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(1U, unwinder.NumFrames());
+}
+
+// Verify SP in a device stops the unwind.
+TEST_F(UnwinderTest, sp_in_device_stops_unwind) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame2", 2));
+
+  regs_.FakeSetPc(0x1000);
+  regs_.FakeSetSp(0x13000);
+  ElfInterfaceFake::FakePushStepData(StepData(0x23002, 0x10010, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0x23102, 0x10020, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0, 0, true));
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(1U, unwinder.NumFrames());
+}
+
+// Verify a no map info frame gets a frame.
+TEST_F(UnwinderTest, pc_without_map) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+
+  regs_.FakeSetPc(0x41000);
+  regs_.FakeSetSp(0x13000);
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(1U, unwinder.NumFrames());
+
+  auto* frame = &unwinder.frames()[0];
+  EXPECT_EQ(0U, frame->num);
+  EXPECT_EQ(0x41000U, frame->rel_pc);
+  EXPECT_EQ(0x41000U, frame->pc);
+  EXPECT_EQ(0x13000U, frame->sp);
+  EXPECT_EQ("", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0U, frame->map_start);
+  EXPECT_EQ(0U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(0, frame->map_flags);
+}
+
+// Verify that a speculative frame is added.
+TEST_F(UnwinderTest, speculative_frame) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+
+  // Fake as if code called a nullptr function.
+  regs_.FakeSetPc(0);
+  regs_.FakeSetSp(0x10000);
+  regs_.FakeSetReturnAddress(0x1202);
+  regs_.FakeSetReturnAddressValid(true);
+
+  ElfInterfaceFake::FakePushStepData(StepData(0x23102, 0x10020, false));
+  ElfInterfaceFake::FakePushStepData(StepData(0, 0, true));
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(3U, unwinder.NumFrames());
+
+  auto* frame = &unwinder.frames()[0];
+  EXPECT_EQ(0U, frame->num);
+  EXPECT_EQ(0U, frame->rel_pc);
+  EXPECT_EQ(0U, frame->pc);
+  EXPECT_EQ(0x10000U, frame->sp);
+  EXPECT_EQ("", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0U, frame->map_start);
+  EXPECT_EQ(0U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(0, frame->map_flags);
+
+  frame = &unwinder.frames()[1];
+  EXPECT_EQ(1U, frame->num);
+  EXPECT_EQ(0x200U, frame->rel_pc);
+  EXPECT_EQ(0x1200U, frame->pc);
+  EXPECT_EQ(0x10000U, frame->sp);
+  EXPECT_EQ("Frame0", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("/system/fake/libc.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x1000U, frame->map_start);
+  EXPECT_EQ(0x8000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+
+  frame = &unwinder.frames()[2];
+  EXPECT_EQ(2U, frame->num);
+  EXPECT_EQ(0x100U, frame->rel_pc);
+  EXPECT_EQ(0x23100U, frame->pc);
+  EXPECT_EQ(0x10020U, frame->sp);
+  EXPECT_EQ("Frame1", frame->function_name);
+  EXPECT_EQ(1U, frame->function_offset);
+  EXPECT_EQ("/fake/libanother.so", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0x23000U, frame->map_start);
+  EXPECT_EQ(0x24000U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(PROT_READ | PROT_WRITE, frame->map_flags);
+}
+
+// Verify that a speculative frame is added then removed because no other
+// frames are added.
+TEST_F(UnwinderTest, speculative_frame_removed) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 0));
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame1", 1));
+
+  // Fake as if code called a nullptr function.
+  regs_.FakeSetPc(0);
+  regs_.FakeSetSp(0x10000);
+  regs_.FakeSetReturnAddress(0x1202);
+  regs_.FakeSetReturnAddressValid(true);
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(1U, unwinder.NumFrames());
+
+  auto* frame = &unwinder.frames()[0];
+  EXPECT_EQ(0U, frame->num);
+  EXPECT_EQ(0U, frame->rel_pc);
+  EXPECT_EQ(0U, frame->pc);
+  EXPECT_EQ(0x10000U, frame->sp);
+  EXPECT_EQ("", frame->function_name);
+  EXPECT_EQ(0U, frame->function_offset);
+  EXPECT_EQ("", frame->map_name);
+  EXPECT_EQ(0U, frame->map_offset);
+  EXPECT_EQ(0U, frame->map_start);
+  EXPECT_EQ(0U, frame->map_end);
+  EXPECT_EQ(0U, frame->map_load_bias);
+  EXPECT_EQ(0, frame->map_flags);
+}
+
+// Verify format frame code.
+TEST_F(UnwinderTest, format_frame_static) {
+  FrameData frame;
+  frame.num = 1;
+  frame.rel_pc = 0x1000;
+  frame.pc = 0x4000;
+  frame.sp = 0x1000;
+  frame.function_name = "function";
+  frame.function_offset = 100;
+  frame.map_name = "/fake/libfake.so";
+  frame.map_offset = 0x2000;
+  frame.map_start = 0x3000;
+  frame.map_end = 0x6000;
+  frame.map_flags = PROT_READ;
+
+  EXPECT_EQ("  #01 pc 0000000000001000 (offset 0x2000)  /fake/libfake.so (function+100)",
+            Unwinder::FormatFrame(frame, false));
+  EXPECT_EQ("  #01 pc 00001000 (offset 0x2000)  /fake/libfake.so (function+100)",
+            Unwinder::FormatFrame(frame, true));
+
+  frame.map_offset = 0;
+  EXPECT_EQ("  #01 pc 0000000000001000  /fake/libfake.so (function+100)",
+            Unwinder::FormatFrame(frame, false));
+  EXPECT_EQ("  #01 pc 00001000  /fake/libfake.so (function+100)",
+            Unwinder::FormatFrame(frame, true));
+
+  frame.function_offset = 0;
+  EXPECT_EQ("  #01 pc 0000000000001000  /fake/libfake.so (function)",
+            Unwinder::FormatFrame(frame, false));
+  EXPECT_EQ("  #01 pc 00001000  /fake/libfake.so (function)", Unwinder::FormatFrame(frame, true));
+
+  frame.function_name = "";
+  EXPECT_EQ("  #01 pc 0000000000001000  /fake/libfake.so", Unwinder::FormatFrame(frame, false));
+  EXPECT_EQ("  #01 pc 00001000  /fake/libfake.so", Unwinder::FormatFrame(frame, true));
+
+  frame.map_name = "";
+  EXPECT_EQ("  #01 pc 0000000000001000  <anonymous:3000>", Unwinder::FormatFrame(frame, false));
+  EXPECT_EQ("  #01 pc 00001000  <anonymous:3000>", Unwinder::FormatFrame(frame, true));
+
+  frame.map_start = 0;
+  frame.map_end = 0;
+  EXPECT_EQ("  #01 pc 0000000000001000  <unknown>", Unwinder::FormatFrame(frame, false));
+  EXPECT_EQ("  #01 pc 00001000  <unknown>", Unwinder::FormatFrame(frame, true));
+}
+
+// Verify format frame code.
+TEST_F(UnwinderTest, format_frame) {
+  ElfInterfaceFake::FakePushFunctionData(FunctionData("Frame0", 10));
+
+  regs_.FakeSetPc(0x2300);
+  regs_.FakeSetSp(0x10000);
+
+  Unwinder unwinder(64, &maps_, &regs_, process_memory_);
+  unwinder.Unwind();
+
+  ASSERT_EQ(1U, unwinder.NumFrames());
+
+  regs_.FakeSetMachineType(EM_ARM);
+  EXPECT_EQ("  #00 pc 00001300  /system/fake/libc.so (Frame0+10)", unwinder.FormatFrame(0));
+  regs_.FakeSetMachineType(EM_386);
+  EXPECT_EQ("  #00 pc 00001300  /system/fake/libc.so (Frame0+10)", unwinder.FormatFrame(0));
+
+  regs_.FakeSetMachineType(EM_AARCH64);
+  EXPECT_EQ("  #00 pc 0000000000001300  /system/fake/libc.so (Frame0+10)", unwinder.FormatFrame(0));
+  regs_.FakeSetMachineType(EM_X86_64);
+  EXPECT_EQ("  #00 pc 0000000000001300  /system/fake/libc.so (Frame0+10)", unwinder.FormatFrame(0));
+
+  EXPECT_EQ("", unwinder.FormatFrame(1));
+}
+
+}  // namespace unwindstack