Add a global elf cache.

Bug: 65682279

Test: Ran new unit tests.
Change-Id: I19c64614b2b11a27f58204d4cc34913c02e04c36

1 files changed, 201 insertions, 0 deletions

diff --git a/libunwindstack/tests/ElfCacheTest.cpp b/libunwindstack/tests/ElfCacheTest.cpp
new file mode 100644
index 000000000..0086c9edb
--- /dev/null
+++ b/libunwindstack/tests/ElfCacheTest.cpp
@@ -0,0 +1,201 @@
+/*
+ * 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 <unistd.h>
+
+#include <android-base/file.h>
+#include <android-base/test_utils.h>
+
+#include <gtest/gtest.h>
+
+#include <unwindstack/Elf.h>
+#include <unwindstack/MapInfo.h>
+
+#include "ElfTestUtils.h"
+#include "MemoryFake.h"
+
+namespace unwindstack {
+
+class ElfCacheTest : public ::testing::Test {
+ protected:
+  static void SetUpTestCase() { memory_.reset(new MemoryFake); }
+
+  void SetUp() override { Elf::SetCachingEnabled(true); }
+
+  void TearDown() override { Elf::SetCachingEnabled(false); }
+
+  void WriteElfFile(uint64_t offset, TemporaryFile* tf, uint32_t type) {
+    ASSERT_TRUE(type == EM_ARM || type == EM_386 || type == EM_X86_64);
+    size_t ehdr_size;
+    Elf32_Ehdr ehdr32;
+    Elf64_Ehdr ehdr64;
+    void* ptr;
+    if (type == EM_ARM || type == EM_386) {
+      ehdr_size = sizeof(ehdr32);
+      ptr = &ehdr32;
+      TestInitEhdr(&ehdr32, ELFCLASS32, type);
+    } else {
+      ehdr_size = sizeof(ehdr64);
+      ptr = &ehdr64;
+      TestInitEhdr(&ehdr64, ELFCLASS64, type);
+    }
+
+    ASSERT_EQ(offset, static_cast<uint64_t>(lseek(tf->fd, offset, SEEK_SET)));
+    ASSERT_TRUE(android::base::WriteFully(tf->fd, ptr, ehdr_size));
+  }
+
+  void VerifyWithinSameMap(bool cache_enabled);
+  void VerifySameMap(bool cache_enabled);
+
+  static std::shared_ptr<Memory> memory_;
+};
+
+std::shared_ptr<Memory> ElfCacheTest::memory_;
+
+void ElfCacheTest::VerifySameMap(bool cache_enabled) {
+  if (!cache_enabled) {
+    Elf::SetCachingEnabled(false);
+  }
+
+  TemporaryFile tf;
+  ASSERT_TRUE(tf.fd != -1);
+  WriteElfFile(0, &tf, EM_ARM);
+  close(tf.fd);
+
+  uint64_t start = 0x1000;
+  uint64_t end = 0x20000;
+  MapInfo info1(start, end, 0, 0x5, tf.path);
+  MapInfo info2(start, end, 0, 0x5, tf.path);
+
+  Elf* elf1 = info1.GetElf(memory_, true);
+  ASSERT_TRUE(elf1->valid());
+  Elf* elf2 = info2.GetElf(memory_, true);
+  ASSERT_TRUE(elf2->valid());
+
+  if (cache_enabled) {
+    EXPECT_EQ(elf1, elf2);
+  } else {
+    EXPECT_NE(elf1, elf2);
+  }
+}
+
+TEST_F(ElfCacheTest, no_caching) {
+  VerifySameMap(false);
+}
+
+TEST_F(ElfCacheTest, caching_invalid_elf) {
+  VerifySameMap(true);
+}
+
+void ElfCacheTest::VerifyWithinSameMap(bool cache_enabled) {
+  if (!cache_enabled) {
+    Elf::SetCachingEnabled(false);
+  }
+
+  TemporaryFile tf;
+  ASSERT_TRUE(tf.fd != -1);
+  WriteElfFile(0, &tf, EM_ARM);
+  WriteElfFile(0x100, &tf, EM_386);
+  WriteElfFile(0x200, &tf, EM_X86_64);
+  lseek(tf.fd, 0x500, SEEK_SET);
+  uint8_t value = 0;
+  write(tf.fd, &value, 1);
+  close(tf.fd);
+
+  uint64_t start = 0x1000;
+  uint64_t end = 0x20000;
+  // Will have an elf at offset 0 in file.
+  MapInfo info0_1(start, end, 0, 0x5, tf.path);
+  MapInfo info0_2(start, end, 0, 0x5, tf.path);
+  // Will have an elf at offset 0x100 in file.
+  MapInfo info100_1(start, end, 0x100, 0x5, tf.path);
+  MapInfo info100_2(start, end, 0x100, 0x5, tf.path);
+  // Will have an elf at offset 0x200 in file.
+  MapInfo info200_1(start, end, 0x200, 0x5, tf.path);
+  MapInfo info200_2(start, end, 0x200, 0x5, tf.path);
+  // Will have an elf at offset 0 in file.
+  MapInfo info300_1(start, end, 0x300, 0x5, tf.path);
+  MapInfo info300_2(start, end, 0x300, 0x5, tf.path);
+
+  Elf* elf0_1 = info0_1.GetElf(memory_, true);
+  ASSERT_TRUE(elf0_1->valid());
+  EXPECT_EQ(ARCH_ARM, elf0_1->arch());
+  Elf* elf0_2 = info0_2.GetElf(memory_, true);
+  ASSERT_TRUE(elf0_2->valid());
+  EXPECT_EQ(ARCH_ARM, elf0_2->arch());
+  EXPECT_EQ(0U, info0_1.elf_offset);
+  EXPECT_EQ(0U, info0_2.elf_offset);
+  if (cache_enabled) {
+    EXPECT_EQ(elf0_1, elf0_2);
+  } else {
+    EXPECT_NE(elf0_1, elf0_2);
+  }
+
+  Elf* elf100_1 = info100_1.GetElf(memory_, true);
+  ASSERT_TRUE(elf100_1->valid());
+  EXPECT_EQ(ARCH_X86, elf100_1->arch());
+  Elf* elf100_2 = info100_2.GetElf(memory_, true);
+  ASSERT_TRUE(elf100_2->valid());
+  EXPECT_EQ(ARCH_X86, elf100_2->arch());
+  EXPECT_EQ(0U, info100_1.elf_offset);
+  EXPECT_EQ(0U, info100_2.elf_offset);
+  if (cache_enabled) {
+    EXPECT_EQ(elf100_1, elf100_2);
+  } else {
+    EXPECT_NE(elf100_1, elf100_2);
+  }
+
+  Elf* elf200_1 = info200_1.GetElf(memory_, true);
+  ASSERT_TRUE(elf200_1->valid());
+  EXPECT_EQ(ARCH_X86_64, elf200_1->arch());
+  Elf* elf200_2 = info200_2.GetElf(memory_, true);
+  ASSERT_TRUE(elf200_2->valid());
+  EXPECT_EQ(ARCH_X86_64, elf200_2->arch());
+  EXPECT_EQ(0U, info200_1.elf_offset);
+  EXPECT_EQ(0U, info200_2.elf_offset);
+  if (cache_enabled) {
+    EXPECT_EQ(elf200_1, elf200_2);
+  } else {
+    EXPECT_NE(elf200_1, elf200_2);
+  }
+
+  Elf* elf300_1 = info300_1.GetElf(memory_, true);
+  ASSERT_TRUE(elf300_1->valid());
+  EXPECT_EQ(ARCH_ARM, elf300_1->arch());
+  Elf* elf300_2 = info300_2.GetElf(memory_, true);
+  ASSERT_TRUE(elf300_2->valid());
+  EXPECT_EQ(ARCH_ARM, elf300_2->arch());
+  EXPECT_EQ(0x300U, info300_1.elf_offset);
+  EXPECT_EQ(0x300U, info300_2.elf_offset);
+  if (cache_enabled) {
+    EXPECT_EQ(elf300_1, elf300_2);
+    EXPECT_EQ(elf0_1, elf300_1);
+  } else {
+    EXPECT_NE(elf300_1, elf300_2);
+    EXPECT_NE(elf0_1, elf300_1);
+  }
+}
+
+TEST_F(ElfCacheTest, no_caching_valid_elf_offset_non_zero) {
+  VerifyWithinSameMap(false);
+}
+
+TEST_F(ElfCacheTest, caching_valid_elf_offset_non_zero) {
+  VerifyWithinSameMap(true);
+}
+
+}  // namespace unwindstack