Add ability to read jit gdb data.

Changes:
- New JitDebug class to handle all of the jit gdb interface.
- Add unit tests for all, along with new offline test using debug data.
- Add new Memory type called MemoryOfflineParts that has multiple
  MemoryOffline objects to support the offline test.
- Update the tools to use the JitDebug object.
- Modify libbacktrace to use the JitDebug, but only looking in libart.so
  and libartd.so.
- Change the Format32Bits to Is32Bit since it's more accurate and I use
  it in a different context where original name didn't make sense.
- Add a new function to find global variables in an elf file
  (GetGlobalVariable).
- Add a new function to determine if a pc is valid for this elf (IsValidPc).

Bug: 68396769

Test: Ran new unit tests. Added new offline test that uses jit debug data.
Test: Ran art test that generates jit data and verified a crash unwinds
Test: through the jit data.
Change-Id: I6e7ee2f5bab2242028a06feece156dff21c0a974
diff --git a/libunwindstack/tests/JitDebugTest.cpp b/libunwindstack/tests/JitDebugTest.cpp
new file mode 100644
index 0000000..83d7a49
--- /dev/null
+++ b/libunwindstack/tests/JitDebugTest.cpp
@@ -0,0 +1,377 @@
+/*
+ * Copyright (C) 2018 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 <string.h>
+
+#include <memory>
+#include <vector>
+
+#include <gtest/gtest.h>
+
+#include <unwindstack/Elf.h>
+#include <unwindstack/JitDebug.h>
+#include <unwindstack/MapInfo.h>
+#include <unwindstack/Maps.h>
+#include <unwindstack/Memory.h>
+
+#include "ElfFake.h"
+#include "MemoryFake.h"
+
+namespace unwindstack {
+
+class JitDebugTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    memory_ = new MemoryFake;
+    process_memory_.reset(memory_);
+
+    jit_debug_.reset(new JitDebug(process_memory_));
+    jit_debug_->SetArch(ARCH_ARM);
+
+    maps_.reset(
+        new BufferMaps("1000-4000 ---s 00000000 00:00 0\n"
+                       "4000-6000 r--s 00000000 00:00 0\n"
+                       "6000-8000 -w-s 00000000 00:00 0\n"
+                       "a000-c000 --xp 00000000 00:00 0\n"
+                       "c000-f000 rwxp 00000000 00:00 0\n"
+                       "f000-11000 r-xp 00000000 00:00 0\n"
+                       "100000-110000 rw-p 0000000 00:00 0\n"
+                       "200000-210000 rw-p 0000000 00:00 0\n"));
+    ASSERT_TRUE(maps_->Parse());
+
+    MapInfo* map_info = maps_->Get(3);
+    ASSERT_TRUE(map_info != nullptr);
+    elf_memories_.push_back(new MemoryFake);
+    ElfFake* elf = new ElfFake(elf_memories_.back());
+    elf->FakeSetValid(true);
+    ElfInterfaceFake* interface = new ElfInterfaceFake(elf_memories_.back());
+    elf->FakeSetInterface(interface);
+    interface->FakeSetGlobalVariable("__jit_debug_descriptor", 0x800);
+    map_info->elf = elf;
+
+    map_info = maps_->Get(5);
+    ASSERT_TRUE(map_info != nullptr);
+    elf_memories_.push_back(new MemoryFake);
+    elf = new ElfFake(elf_memories_.back());
+    elf->FakeSetValid(true);
+    interface = new ElfInterfaceFake(elf_memories_.back());
+    elf->FakeSetInterface(interface);
+    interface->FakeSetGlobalVariable("__jit_debug_descriptor", 0x800);
+    map_info->elf = elf;
+  }
+
+  template <typename EhdrType, typename ShdrType>
+  void CreateElf(uint64_t offset, uint8_t class_type, uint8_t machine_type, uint32_t pc,
+                 uint32_t size) {
+    EhdrType ehdr;
+    memset(&ehdr, 0, sizeof(ehdr));
+    uint64_t sh_offset = sizeof(ehdr);
+    memcpy(ehdr.e_ident, ELFMAG, SELFMAG);
+    ehdr.e_ident[EI_CLASS] = class_type;
+    ehdr.e_machine = machine_type;
+    ehdr.e_shstrndx = 1;
+    ehdr.e_shoff = sh_offset;
+    ehdr.e_shentsize = sizeof(ShdrType);
+    ehdr.e_shnum = 3;
+    memory_->SetMemory(offset, &ehdr, sizeof(ehdr));
+
+    ShdrType shdr;
+    memset(&shdr, 0, sizeof(shdr));
+    shdr.sh_type = SHT_NULL;
+    memory_->SetMemory(offset + sh_offset, &shdr, sizeof(shdr));
+
+    sh_offset += sizeof(shdr);
+    memset(&shdr, 0, sizeof(shdr));
+    shdr.sh_type = SHT_STRTAB;
+    shdr.sh_name = 1;
+    shdr.sh_offset = 0x500;
+    shdr.sh_size = 0x100;
+    memory_->SetMemory(offset + sh_offset, &shdr, sizeof(shdr));
+    memory_->SetMemory(offset + 0x500, ".debug_frame");
+
+    sh_offset += sizeof(shdr);
+    memset(&shdr, 0, sizeof(shdr));
+    shdr.sh_type = SHT_PROGBITS;
+    shdr.sh_name = 0;
+    shdr.sh_addr = 0x600;
+    shdr.sh_offset = 0x600;
+    shdr.sh_size = 0x200;
+    memory_->SetMemory(offset + sh_offset, &shdr, sizeof(shdr));
+
+    // Now add a single cie/fde.
+    uint64_t dwarf_offset = offset + 0x600;
+    if (class_type == ELFCLASS32) {
+      // CIE 32 information.
+      memory_->SetData32(dwarf_offset, 0xfc);
+      memory_->SetData32(dwarf_offset + 0x4, 0xffffffff);
+      memory_->SetData8(dwarf_offset + 0x8, 1);
+      memory_->SetData8(dwarf_offset + 0x9, '\0');
+      memory_->SetData8(dwarf_offset + 0xa, 0x4);
+      memory_->SetData8(dwarf_offset + 0xb, 0x4);
+      memory_->SetData8(dwarf_offset + 0xc, 0x1);
+
+      // FDE 32 information.
+      memory_->SetData32(dwarf_offset + 0x100, 0xfc);
+      memory_->SetData32(dwarf_offset + 0x104, 0);
+      memory_->SetData32(dwarf_offset + 0x108, pc);
+      memory_->SetData32(dwarf_offset + 0x10c, size);
+    } else {
+      // CIE 64 information.
+      memory_->SetData32(dwarf_offset, 0xffffffff);
+      memory_->SetData64(dwarf_offset + 4, 0xf4);
+      memory_->SetData64(dwarf_offset + 0xc, 0xffffffffffffffffULL);
+      memory_->SetData8(dwarf_offset + 0x14, 1);
+      memory_->SetData8(dwarf_offset + 0x15, '\0');
+      memory_->SetData8(dwarf_offset + 0x16, 0x4);
+      memory_->SetData8(dwarf_offset + 0x17, 0x4);
+      memory_->SetData8(dwarf_offset + 0x18, 0x1);
+
+      // FDE 64 information.
+      memory_->SetData32(dwarf_offset + 0x100, 0xffffffff);
+      memory_->SetData64(dwarf_offset + 0x104, 0xf4);
+      memory_->SetData64(dwarf_offset + 0x10c, 0);
+      memory_->SetData64(dwarf_offset + 0x114, pc);
+      memory_->SetData64(dwarf_offset + 0x11c, size);
+    }
+  }
+
+  void WriteDescriptor32(uint64_t addr, uint32_t entry);
+  void WriteDescriptor64(uint64_t addr, uint64_t entry);
+  void WriteEntry32Pack(uint64_t addr, uint32_t prev, uint32_t next, uint32_t elf_addr,
+                        uint64_t elf_size);
+  void WriteEntry32Pad(uint64_t addr, uint32_t prev, uint32_t next, uint32_t elf_addr,
+                       uint64_t elf_size);
+  void WriteEntry64(uint64_t addr, uint64_t prev, uint64_t next, uint64_t elf_addr,
+                    uint64_t elf_size);
+
+  std::shared_ptr<Memory> process_memory_;
+  MemoryFake* memory_;
+  std::vector<MemoryFake*> elf_memories_;
+  std::unique_ptr<JitDebug> jit_debug_;
+  std::unique_ptr<BufferMaps> maps_;
+};
+
+void JitDebugTest::WriteDescriptor32(uint64_t addr, uint32_t entry) {
+  // Format of the 32 bit JITDescriptor structure:
+  //   uint32_t version
+  memory_->SetData32(addr, 1);
+  //   uint32_t action_flag
+  memory_->SetData32(addr + 4, 0);
+  //   uint32_t relevant_entry
+  memory_->SetData32(addr + 8, 0);
+  //   uint32_t first_entry
+  memory_->SetData32(addr + 12, entry);
+}
+
+void JitDebugTest::WriteDescriptor64(uint64_t addr, uint64_t entry) {
+  // Format of the 64 bit JITDescriptor structure:
+  //   uint32_t version
+  memory_->SetData32(addr, 1);
+  //   uint32_t action_flag
+  memory_->SetData32(addr + 4, 0);
+  //   uint64_t relevant_entry
+  memory_->SetData64(addr + 8, 0);
+  //   uint64_t first_entry
+  memory_->SetData64(addr + 16, entry);
+}
+
+void JitDebugTest::WriteEntry32Pack(uint64_t addr, uint32_t prev, uint32_t next, uint32_t elf_addr,
+                                    uint64_t elf_size) {
+  // Format of the 32 bit JITCodeEntry structure:
+  //   uint32_t next
+  memory_->SetData32(addr, next);
+  //   uint32_t prev
+  memory_->SetData32(addr + 4, prev);
+  //   uint32_t symfile_addr
+  memory_->SetData32(addr + 8, elf_addr);
+  //   uint64_t symfile_size
+  memory_->SetData64(addr + 12, elf_size);
+}
+
+void JitDebugTest::WriteEntry32Pad(uint64_t addr, uint32_t prev, uint32_t next, uint32_t elf_addr,
+                                   uint64_t elf_size) {
+  // Format of the 32 bit JITCodeEntry structure:
+  //   uint32_t next
+  memory_->SetData32(addr, next);
+  //   uint32_t prev
+  memory_->SetData32(addr + 4, prev);
+  //   uint32_t symfile_addr
+  memory_->SetData32(addr + 8, elf_addr);
+  //   uint32_t pad
+  memory_->SetData32(addr + 12, 0);
+  //   uint64_t symfile_size
+  memory_->SetData64(addr + 16, elf_size);
+}
+
+void JitDebugTest::WriteEntry64(uint64_t addr, uint64_t prev, uint64_t next, uint64_t elf_addr,
+                                uint64_t elf_size) {
+  // Format of the 64 bit JITCodeEntry structure:
+  //   uint64_t next
+  memory_->SetData64(addr, next);
+  //   uint64_t prev
+  memory_->SetData64(addr + 8, prev);
+  //   uint64_t symfile_addr
+  memory_->SetData64(addr + 16, elf_addr);
+  //   uint64_t symfile_size
+  memory_->SetData64(addr + 24, elf_size);
+}
+
+TEST_F(JitDebugTest, get_elf_invalid) {
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf == nullptr);
+}
+
+TEST_F(JitDebugTest, get_elf_no_global_variable) {
+  maps_.reset(new BufferMaps(""));
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf == nullptr);
+}
+
+TEST_F(JitDebugTest, get_elf_no_valid_descriptor_in_memory) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf == nullptr);
+}
+
+TEST_F(JitDebugTest, get_elf_no_valid_code_entry) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+
+  WriteDescriptor32(0xf800, 0x200000);
+
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf == nullptr);
+}
+
+TEST_F(JitDebugTest, get_elf_invalid_descriptor_first_entry) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+
+  WriteDescriptor32(0xf800, 0);
+
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf == nullptr);
+}
+
+TEST_F(JitDebugTest, get_elf_invalid_descriptor_version) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+
+  WriteDescriptor32(0xf800, 0x20000);
+  // Set the version to an invalid value.
+  memory_->SetData32(0xf800, 2);
+
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf == nullptr);
+}
+
+TEST_F(JitDebugTest, get_elf_32) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+
+  WriteDescriptor32(0xf800, 0x200000);
+  WriteEntry32Pad(0x200000, 0, 0, 0x4000, 0x1000);
+
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf != nullptr);
+
+  // Clear the memory and verify all of the data is cached.
+  memory_->Clear();
+  Elf* elf2 = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf2 != nullptr);
+  EXPECT_EQ(elf, elf2);
+}
+
+TEST_F(JitDebugTest, get_elf_x86) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+
+  WriteDescriptor32(0xf800, 0x200000);
+  WriteEntry32Pack(0x200000, 0, 0, 0x4000, 0x1000);
+
+  jit_debug_->SetArch(ARCH_X86);
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf != nullptr);
+
+  // Clear the memory and verify all of the data is cached.
+  memory_->Clear();
+  Elf* elf2 = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf2 != nullptr);
+  EXPECT_EQ(elf, elf2);
+}
+
+TEST_F(JitDebugTest, get_elf_64) {
+  CreateElf<Elf64_Ehdr, Elf64_Shdr>(0x4000, ELFCLASS64, EM_AARCH64, 0x1500, 0x200);
+
+  WriteDescriptor64(0xf800, 0x200000);
+  WriteEntry64(0x200000, 0, 0, 0x4000, 0x1000);
+
+  jit_debug_->SetArch(ARCH_ARM64);
+  Elf* elf = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf != nullptr);
+
+  // Clear the memory and verify all of the data is cached.
+  memory_->Clear();
+  Elf* elf2 = jit_debug_->GetElf(maps_.get(), 0x1500);
+  ASSERT_TRUE(elf2 != nullptr);
+  EXPECT_EQ(elf, elf2);
+}
+
+TEST_F(JitDebugTest, get_elf_multiple_entries) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x5000, ELFCLASS32, EM_ARM, 0x2300, 0x400);
+
+  WriteDescriptor32(0xf800, 0x200000);
+  WriteEntry32Pad(0x200000, 0, 0x200100, 0x4000, 0x1000);
+  WriteEntry32Pad(0x200100, 0x200100, 0, 0x5000, 0x1000);
+
+  Elf* elf_2 = jit_debug_->GetElf(maps_.get(), 0x2400);
+  ASSERT_TRUE(elf_2 != nullptr);
+
+  Elf* elf_1 = jit_debug_->GetElf(maps_.get(), 0x1600);
+  ASSERT_TRUE(elf_1 != nullptr);
+
+  // Clear the memory and verify all of the data is cached.
+  memory_->Clear();
+  EXPECT_EQ(elf_1, jit_debug_->GetElf(maps_.get(), 0x1500));
+  EXPECT_EQ(elf_1, jit_debug_->GetElf(maps_.get(), 0x16ff));
+  EXPECT_EQ(elf_2, jit_debug_->GetElf(maps_.get(), 0x2300));
+  EXPECT_EQ(elf_2, jit_debug_->GetElf(maps_.get(), 0x26ff));
+  EXPECT_EQ(nullptr, jit_debug_->GetElf(maps_.get(), 0x1700));
+  EXPECT_EQ(nullptr, jit_debug_->GetElf(maps_.get(), 0x2700));
+}
+
+TEST_F(JitDebugTest, get_elf_search_libs) {
+  CreateElf<Elf32_Ehdr, Elf32_Shdr>(0x4000, ELFCLASS32, EM_ARM, 0x1500, 0x200);
+
+  WriteDescriptor32(0xf800, 0x200000);
+  WriteEntry32Pad(0x200000, 0, 0, 0x4000, 0x1000);
+
+  // Only search a given named list of libs.
+  std::vector<std::string> libs{"libart.so"};
+  jit_debug_.reset(new JitDebug(process_memory_, libs));
+  jit_debug_->SetArch(ARCH_ARM);
+  EXPECT_TRUE(jit_debug_->GetElf(maps_.get(), 0x1500) == nullptr);
+
+  // Change the name of the map that includes the value and verify this works.
+  MapInfo* map_info = maps_->Get(5);
+  map_info->name = "/system/lib/libart.so";
+  jit_debug_.reset(new JitDebug(process_memory_, libs));
+  // Make sure that clearing our copy of the libs doesn't affect the
+  // JitDebug object.
+  libs.clear();
+  jit_debug_->SetArch(ARCH_ARM);
+  EXPECT_TRUE(jit_debug_->GetElf(maps_.get(), 0x1500) != nullptr);
+}
+
+}  // namespace unwindstack