Elf interface for new unwinder.

This cl includes the code to read arm unwind information from a shared
library.

Bug: 23762183

Test: Passes all unit tests. I can dump the arm unwind information
Test: for an arm shared library.
Change-Id: I43501ea2eab843b81de8bd5128401dd1971af8d3
diff --git a/libunwindstack/tests/ElfInterfaceArmTest.cpp b/libunwindstack/tests/ElfInterfaceArmTest.cpp
new file mode 100644
index 0000000..67c9a6b
--- /dev/null
+++ b/libunwindstack/tests/ElfInterfaceArmTest.cpp
@@ -0,0 +1,372 @@
+/*
+ * Copyright (C) 2016 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 <gtest/gtest.h>
+
+#include <vector>
+
+#include "ElfInterfaceArm.h"
+#include "Machine.h"
+#include "Regs.h"
+
+#include "MemoryFake.h"
+
+class ElfInterfaceArmTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    memory_.Clear();
+    process_memory_.Clear();
+  }
+
+  MemoryFake memory_;
+  MemoryFake process_memory_;
+};
+
+TEST_F(ElfInterfaceArmTest, GetPrel32Addr) {
+  ElfInterfaceArm interface(&memory_);
+  memory_.SetData32(0x1000, 0x230000);
+
+  uint32_t value;
+  ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
+  ASSERT_EQ(0x231000U, value);
+
+  memory_.SetData32(0x1000, 0x80001000);
+  ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
+  ASSERT_EQ(0x2000U, value);
+
+  memory_.SetData32(0x1000, 0x70001000);
+  ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
+  ASSERT_EQ(0xf0002000U, value);
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_start_zero) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0);
+  interface.set_total_entries(10);
+
+  uint64_t entry_offset;
+  ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_no_entries) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x100);
+  interface.set_total_entries(0);
+
+  uint64_t entry_offset;
+  ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_no_valid_memory) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x100);
+  interface.set_total_entries(2);
+
+  uint64_t entry_offset;
+  ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_ip_before_first) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(1);
+  memory_.SetData32(0x1000, 0x6000);
+
+  uint64_t entry_offset;
+  ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_single_entry_negative_value) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x8000);
+  interface.set_total_entries(1);
+  memory_.SetData32(0x8000, 0x7fffff00);
+
+  uint64_t entry_offset;
+  ASSERT_TRUE(interface.FindEntry(0x7ff0, &entry_offset));
+  ASSERT_EQ(0x8000U, entry_offset);
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_two_entries) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(2);
+  memory_.SetData32(0x1000, 0x6000);
+  memory_.SetData32(0x1008, 0x7000);
+
+  uint64_t entry_offset;
+  ASSERT_TRUE(interface.FindEntry(0x7000, &entry_offset));
+  ASSERT_EQ(0x1000U, entry_offset);
+}
+
+
+TEST_F(ElfInterfaceArmTest, FindEntry_last_check_single_entry) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(1);
+  memory_.SetData32(0x1000, 0x6000);
+
+  uint64_t entry_offset;
+  ASSERT_TRUE(interface.FindEntry(0x7000, &entry_offset));
+  ASSERT_EQ(0x1000U, entry_offset);
+
+  // To guarantee that we are using the cache on the second run,
+  // set the memory to a different value.
+  memory_.SetData32(0x1000, 0x8000);
+  ASSERT_TRUE(interface.FindEntry(0x7004, &entry_offset));
+  ASSERT_EQ(0x1000U, entry_offset);
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_last_check_multiple_entries) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(2);
+  memory_.SetData32(0x1000, 0x6000);
+  memory_.SetData32(0x1008, 0x8000);
+
+  uint64_t entry_offset;
+  ASSERT_TRUE(interface.FindEntry(0x9008, &entry_offset));
+  ASSERT_EQ(0x1008U, entry_offset);
+
+  // To guarantee that we are using the cache on the second run,
+  // set the memory to a different value.
+  memory_.SetData32(0x1000, 0x16000);
+  memory_.SetData32(0x1008, 0x18000);
+  ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
+  ASSERT_EQ(0x1008U, entry_offset);
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_multiple_entries_even) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(4);
+  memory_.SetData32(0x1000, 0x6000);
+  memory_.SetData32(0x1008, 0x7000);
+  memory_.SetData32(0x1010, 0x8000);
+  memory_.SetData32(0x1018, 0x9000);
+
+  uint64_t entry_offset;
+  ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
+  ASSERT_EQ(0x1010U, entry_offset);
+
+  // To guarantee that we are using the cache on the second run,
+  // set the memory to a different value.
+  memory_.SetData32(0x1000, 0x16000);
+  memory_.SetData32(0x1008, 0x17000);
+  memory_.SetData32(0x1010, 0x18000);
+  memory_.SetData32(0x1018, 0x19000);
+  ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
+  ASSERT_EQ(0x1010U, entry_offset);
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_multiple_entries_odd) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(5);
+  memory_.SetData32(0x1000, 0x5000);
+  memory_.SetData32(0x1008, 0x6000);
+  memory_.SetData32(0x1010, 0x7000);
+  memory_.SetData32(0x1018, 0x8000);
+  memory_.SetData32(0x1020, 0x9000);
+
+  uint64_t entry_offset;
+  ASSERT_TRUE(interface.FindEntry(0x8100, &entry_offset));
+  ASSERT_EQ(0x1010U, entry_offset);
+
+  // To guarantee that we are using the cache on the second run,
+  // set the memory to a different value.
+  memory_.SetData32(0x1000, 0x15000);
+  memory_.SetData32(0x1008, 0x16000);
+  memory_.SetData32(0x1010, 0x17000);
+  memory_.SetData32(0x1018, 0x18000);
+  memory_.SetData32(0x1020, 0x19000);
+  ASSERT_TRUE(interface.FindEntry(0x8100, &entry_offset));
+  ASSERT_EQ(0x1010U, entry_offset);
+}
+
+TEST_F(ElfInterfaceArmTest, iterate) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(5);
+  memory_.SetData32(0x1000, 0x5000);
+  memory_.SetData32(0x1008, 0x6000);
+  memory_.SetData32(0x1010, 0x7000);
+  memory_.SetData32(0x1018, 0x8000);
+  memory_.SetData32(0x1020, 0x9000);
+
+  std::vector<uint32_t> entries;
+  for (auto addr : interface) {
+    entries.push_back(addr);
+  }
+  ASSERT_EQ(5U, entries.size());
+  ASSERT_EQ(0x6000U, entries[0]);
+  ASSERT_EQ(0x7008U, entries[1]);
+  ASSERT_EQ(0x8010U, entries[2]);
+  ASSERT_EQ(0x9018U, entries[3]);
+  ASSERT_EQ(0xa020U, entries[4]);
+
+  // Make sure the iterate cached the entries.
+  memory_.SetData32(0x1000, 0x11000);
+  memory_.SetData32(0x1008, 0x12000);
+  memory_.SetData32(0x1010, 0x13000);
+  memory_.SetData32(0x1018, 0x14000);
+  memory_.SetData32(0x1020, 0x15000);
+
+  entries.clear();
+  for (auto addr : interface) {
+    entries.push_back(addr);
+  }
+  ASSERT_EQ(5U, entries.size());
+  ASSERT_EQ(0x6000U, entries[0]);
+  ASSERT_EQ(0x7008U, entries[1]);
+  ASSERT_EQ(0x8010U, entries[2]);
+  ASSERT_EQ(0x9018U, entries[3]);
+  ASSERT_EQ(0xa020U, entries[4]);
+}
+
+TEST_F(ElfInterfaceArmTest, FindEntry_load_bias) {
+  ElfInterfaceArm interface(&memory_);
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(2);
+  memory_.SetData32(0x1000, 0x6000);
+  memory_.SetData32(0x1008, 0x8000);
+
+  uint64_t entry_offset;
+  interface.set_load_bias(0x2000);
+  ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
+  ASSERT_FALSE(interface.FindEntry(0x8000, &entry_offset));
+  ASSERT_FALSE(interface.FindEntry(0x8fff, &entry_offset));
+  ASSERT_TRUE(interface.FindEntry(0x9000, &entry_offset));
+  ASSERT_EQ(0x1000U, entry_offset);
+  ASSERT_TRUE(interface.FindEntry(0xb007, &entry_offset));
+  ASSERT_EQ(0x1000U, entry_offset);
+  ASSERT_TRUE(interface.FindEntry(0xb008, &entry_offset));
+  ASSERT_EQ(0x1008U, entry_offset);
+}
+
+TEST_F(ElfInterfaceArmTest, HandleType_not_arm_exidx) {
+  ElfInterfaceArm interface(&memory_);
+
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_NULL));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_LOAD));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_DYNAMIC));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_INTERP));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_NOTE));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_SHLIB));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_PHDR));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_TLS));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_LOOS));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_HIOS));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_LOPROC));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_HIPROC));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_GNU_EH_FRAME));
+  ASSERT_FALSE(interface.HandleType(0x1000, PT_GNU_STACK));
+}
+
+TEST_F(ElfInterfaceArmTest, HandleType_arm_exidx) {
+  ElfInterfaceArm interface(&memory_);
+
+  Elf32_Phdr phdr;
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(100);
+  phdr.p_vaddr = 0x2000;
+  phdr.p_memsz = 0xa00;
+
+  // Verify that if reads fail, we don't set the values but still get true.
+  ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
+  ASSERT_EQ(0x1000U, interface.start_offset());
+  ASSERT_EQ(100U, interface.total_entries());
+
+  // Verify that if the second read fails, we still don't set the values.
+  memory_.SetData32(
+      0x1000 + reinterpret_cast<uint64_t>(&phdr.p_vaddr) - reinterpret_cast<uint64_t>(&phdr),
+      phdr.p_vaddr);
+  ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
+  ASSERT_EQ(0x1000U, interface.start_offset());
+  ASSERT_EQ(100U, interface.total_entries());
+
+  // Everything is correct and present.
+  memory_.SetData32(
+      0x1000 + reinterpret_cast<uint64_t>(&phdr.p_memsz) - reinterpret_cast<uint64_t>(&phdr),
+      phdr.p_memsz);
+  ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
+  ASSERT_EQ(0x2000U, interface.start_offset());
+  ASSERT_EQ(320U, interface.total_entries());
+
+  // Non-zero load bias.
+  interface.set_load_bias(0x1000);
+  ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
+  ASSERT_EQ(0x1000U, interface.start_offset());
+  ASSERT_EQ(320U, interface.total_entries());
+}
+
+TEST_F(ElfInterfaceArmTest, StepExidx) {
+  ElfInterfaceArm interface(&memory_);
+
+  // FindEntry fails.
+  ASSERT_FALSE(interface.StepExidx(0x7000, nullptr, nullptr));
+
+  // ExtractEntry should fail.
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(2);
+  memory_.SetData32(0x1000, 0x6000);
+  memory_.SetData32(0x1008, 0x8000);
+
+  RegsArm regs;
+  regs[ARM_REG_SP] = 0x1000;
+  regs[ARM_REG_LR] = 0x20000;
+  regs.set_sp(regs[ARM_REG_SP]);
+  regs.set_pc(0x1234);
+  ASSERT_FALSE(interface.StepExidx(0x7000, &regs, &process_memory_));
+
+  // Eval should fail.
+  memory_.SetData32(0x1004, 0x81000000);
+  ASSERT_FALSE(interface.StepExidx(0x7000, &regs, &process_memory_));
+
+  // Everything should pass.
+  memory_.SetData32(0x1004, 0x80b0b0b0);
+  ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_));
+  ASSERT_EQ(0x1000U, regs.sp());
+  ASSERT_EQ(0x1000U, regs[ARM_REG_SP]);
+  ASSERT_EQ(0x20000U, regs.pc());
+  ASSERT_EQ(0x20000U, regs[ARM_REG_PC]);
+}
+
+TEST_F(ElfInterfaceArmTest, StepExidx_pc_set) {
+  ElfInterfaceArm interface(&memory_);
+
+  interface.set_start_offset(0x1000);
+  interface.set_total_entries(2);
+  memory_.SetData32(0x1000, 0x6000);
+  memory_.SetData32(0x1004, 0x808800b0);
+  memory_.SetData32(0x1008, 0x8000);
+  process_memory_.SetData32(0x10000, 0x10);
+
+  RegsArm regs;
+  regs[ARM_REG_SP] = 0x10000;
+  regs[ARM_REG_LR] = 0x20000;
+  regs.set_sp(regs[ARM_REG_SP]);
+  regs.set_pc(0x1234);
+
+  // Everything should pass.
+  ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_));
+  ASSERT_EQ(0x10004U, regs.sp());
+  ASSERT_EQ(0x10004U, regs[ARM_REG_SP]);
+  ASSERT_EQ(0x10U, regs.pc());
+  ASSERT_EQ(0x10U, regs[ARM_REG_PC]);
+}