1 files changed, 450 insertions, 0 deletions
diff --git a/absl/debugging/symbolize_test.cc b/absl/debugging/symbolize_test.cc
new file mode 100644
index 000000000000..52c6915537e8
--- /dev/null
+++ b/absl/debugging/symbolize_test.cc
@@ -0,0 +1,450 @@
+// Copyright 2018 The Abseil Authors.
+//
+// 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 "absl/debugging/symbolize.h"
+
+#ifndef _WIN32
+#include <fcntl.h>
+#include <sys/mman.h>
+#endif
+
+#include <cstring>
+#include <iostream>
+#include <memory>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/base/attributes.h"
+#include "absl/base/casts.h"
+#include "absl/base/internal/malloc_extension.h"
+#include "absl/base/internal/per_thread_tls.h"
+#include "absl/base/internal/raw_logging.h"
+#include "absl/base/optimization.h"
+#include "absl/debugging/internal/stack_consumption.h"
+#include "absl/memory/memory.h"
+
+using testing::Contains;
+
+// Functions to symbolize. Use C linkage to avoid mangled names.
+extern "C" {
+void nonstatic_func() { ABSL_BLOCK_TAIL_CALL_OPTIMIZATION(); }
+static void static_func() { ABSL_BLOCK_TAIL_CALL_OPTIMIZATION(); }
+}  // extern "C"
+
+struct Foo {
+  static void func(int x);
+};
+
+// A C++ method that should have a mangled name.
+void ABSL_ATTRIBUTE_NOINLINE Foo::func(int) {
+  ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
+}
+
+// Thread-local data may confuse the symbolizer, ensure that it does not.
+// Variable sizes and order are important.
+#if ABSL_PER_THREAD_TLS
+static ABSL_PER_THREAD_TLS_KEYWORD char symbolize_test_thread_small[1];
+static ABSL_PER_THREAD_TLS_KEYWORD char
+    symbolize_test_thread_big[2 * 1024 * 1024];
+#endif
+
+// Used below to hopefully inhibit some compiler/linker optimizations
+// that may remove kHpageTextPadding, kPadding0, and kPadding1 from
+// the binary.
+static volatile bool volatile_bool = false;
+
+// Force the binary to be large enough that a THP .text remap will succeed.
+static constexpr size_t kHpageSize = 1 << 21;
+const char kHpageTextPadding[kHpageSize * 4] ABSL_ATTRIBUTE_SECTION_VARIABLE(
+    ".text") = "";
+
+#ifdef ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE
+
+static char try_symbolize_buffer[4096];
+
+// A wrapper function for absl::Symbolize() to make the unit test simple.  The
+// limit must be < sizeof(try_symbolize_buffer).  Returns null if
+// absl::Symbolize() returns false, otherwise returns try_symbolize_buffer with
+// the result of absl::Symbolize().
+static const char *TrySymbolizeWithLimit(void *pc, int limit) {
+  ABSL_RAW_CHECK(limit <= sizeof(try_symbolize_buffer),
+                 "try_symbolize_buffer is too small");
+
+  // Use the heap to facilitate heap and buffer sanitizer tools.
+  auto heap_buffer = absl::make_unique<char[]>(sizeof(try_symbolize_buffer));
+  bool found = absl::Symbolize(pc, heap_buffer.get(), limit);
+  if (found) {
+    ABSL_RAW_CHECK(strnlen(heap_buffer.get(), limit) < limit,
+                   "absl::Symbolize() did not properly terminate the string");
+    strncpy(try_symbolize_buffer, heap_buffer.get(),
+            sizeof(try_symbolize_buffer));
+  }
+
+  return found ? try_symbolize_buffer : nullptr;
+}
+
+// A wrapper for TrySymbolizeWithLimit(), with a large limit.
+static const char *TrySymbolize(void *pc) {
+  return TrySymbolizeWithLimit(pc, sizeof(try_symbolize_buffer));
+}
+
+TEST(Symbolize, Cached) {
+  // Compilers should give us pointers to them.
+  EXPECT_STREQ("nonstatic_func", TrySymbolize((void *)(&nonstatic_func)));
+
+  // The name of an internal linkage symbol is not specified; allow either a
+  // mangled or an unmangled name here.
+  const char *static_func_symbol = TrySymbolize((void *)(&static_func));
+  EXPECT_TRUE(strcmp("static_func", static_func_symbol) == 0 ||
+              strcmp("static_func()", static_func_symbol) == 0);
+
+  EXPECT_TRUE(nullptr == TrySymbolize(nullptr));
+}
+
+TEST(Symbolize, Truncation) {
+  constexpr char kNonStaticFunc[] = "nonstatic_func";
+  EXPECT_STREQ("nonstatic_func",
+               TrySymbolizeWithLimit((void *)(&nonstatic_func),
+                                     strlen(kNonStaticFunc) + 1));
+  EXPECT_STREQ("nonstatic_...",
+               TrySymbolizeWithLimit((void *)(&nonstatic_func),
+                                     strlen(kNonStaticFunc) + 0));
+  EXPECT_STREQ("nonstatic...",
+               TrySymbolizeWithLimit((void *)(&nonstatic_func),
+                                     strlen(kNonStaticFunc) - 1));
+  EXPECT_STREQ("n...", TrySymbolizeWithLimit((void *)(&nonstatic_func), 5));
+  EXPECT_STREQ("...", TrySymbolizeWithLimit((void *)(&nonstatic_func), 4));
+  EXPECT_STREQ("..", TrySymbolizeWithLimit((void *)(&nonstatic_func), 3));
+  EXPECT_STREQ(".", TrySymbolizeWithLimit((void *)(&nonstatic_func), 2));
+  EXPECT_STREQ("", TrySymbolizeWithLimit((void *)(&nonstatic_func), 1));
+  EXPECT_EQ(nullptr, TrySymbolizeWithLimit((void *)(&nonstatic_func), 0));
+}
+
+TEST(Symbolize, SymbolizeWithDemangling) {
+  Foo::func(100);
+  EXPECT_STREQ("Foo::func()", TrySymbolize((void *)(&Foo::func)));
+}
+
+// Tests that verify that Symbolize stack footprint is within some limit.
+#ifdef ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+
+static void *g_pc_to_symbolize;
+static char g_symbolize_buffer[4096];
+static char *g_symbolize_result;
+
+static void SymbolizeSignalHandler(int signo) {
+  if (absl::Symbolize(g_pc_to_symbolize, g_symbolize_buffer,
+                      sizeof(g_symbolize_buffer))) {
+    g_symbolize_result = g_symbolize_buffer;
+  } else {
+    g_symbolize_result = nullptr;
+  }
+}
+
+// Call Symbolize and figure out the stack footprint of this call.
+static const char *SymbolizeStackConsumption(void *pc, int *stack_consumed) {
+  g_pc_to_symbolize = pc;
+  *stack_consumed = absl::debugging_internal::GetSignalHandlerStackConsumption(
+      SymbolizeSignalHandler);
+  return g_symbolize_result;
+}
+
+static int GetStackConsumptionUpperLimit() {
+  // Symbolize stack consumption should be within 2kB.
+  const int kStackConsumptionUpperLimit = 2048;
+  // Account for ASan/TSan instrumentation requiring additional stack space.
+  size_t multiplier = 0;
+  if (absl::base_internal::MallocExtension::instance()->GetNumericProperty(
+          "dynamic_tool.stack_size_multiplier", &multiplier)) {
+    return kStackConsumptionUpperLimit * multiplier;
+  }
+  return kStackConsumptionUpperLimit;
+}
+
+TEST(Symbolize, SymbolizeStackConsumption) {
+  int stack_consumed = 0;
+
+  const char *symbol =
+      SymbolizeStackConsumption((void *)(&nonstatic_func), &stack_consumed);
+  EXPECT_STREQ("nonstatic_func", symbol);
+  EXPECT_GT(stack_consumed, 0);
+  EXPECT_LT(stack_consumed, GetStackConsumptionUpperLimit());
+
+  // The name of an internal linkage symbol is not specified; allow either a
+  // mangled or an unmangled name here.
+  symbol = SymbolizeStackConsumption((void *)(&static_func), &stack_consumed);
+  EXPECT_TRUE(strcmp("static_func", symbol) == 0 ||
+              strcmp("static_func()", symbol) == 0);
+  EXPECT_GT(stack_consumed, 0);
+  EXPECT_LT(stack_consumed, GetStackConsumptionUpperLimit());
+}
+
+TEST(Symbolize, SymbolizeWithDemanglingStackConsumption) {
+  Foo::func(100);
+  int stack_consumed = 0;
+
+  const char *symbol =
+      SymbolizeStackConsumption((void *)(&Foo::func), &stack_consumed);
+
+  EXPECT_STREQ("Foo::func()", symbol);
+  EXPECT_GT(stack_consumed, 0);
+  EXPECT_LT(stack_consumed, GetStackConsumptionUpperLimit());
+}
+
+#endif  // ABSL_INTERNAL_HAVE_DEBUGGING_STACK_CONSUMPTION
+
+// Use a 64K page size for PPC.
+const size_t kPageSize = 64 << 10;
+// We place a read-only symbols into the .text section and verify that we can
+// symbolize them and other symbols after remapping them.
+const char kPadding0[kPageSize * 4] ABSL_ATTRIBUTE_SECTION_VARIABLE(".text") =
+    "";
+const char kPadding1[kPageSize * 4] ABSL_ATTRIBUTE_SECTION_VARIABLE(".text") =
+    "";
+
+static int FilterElfHeader(struct dl_phdr_info *info, size_t size, void *data) {
+  for (int i = 0; i < info->dlpi_phnum; i++) {
+    if (info->dlpi_phdr[i].p_type == PT_LOAD &&
+        info->dlpi_phdr[i].p_flags == (PF_R | PF_X)) {
+      const void *const vaddr =
+          absl::bit_cast<void *>(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
+      const auto segsize = info->dlpi_phdr[i].p_memsz;
+
+      const char *self_exe;
+      if (info->dlpi_name != nullptr && info->dlpi_name[0] != '\0') {
+        self_exe = info->dlpi_name;
+      } else {
+        self_exe = "/proc/self/exe";
+      }
+
+      absl::debugging_internal::RegisterFileMappingHint(
+          vaddr, reinterpret_cast<const char *>(vaddr) + segsize,
+          info->dlpi_phdr[i].p_offset, self_exe);
+
+      return 1;
+    }
+  }
+
+  return 1;
+}
+
+TEST(Symbolize, SymbolizeWithMultipleMaps) {
+  // Force kPadding0 and kPadding1 to be linked in.
+  if (volatile_bool) {
+    ABSL_RAW_LOG(INFO, "%s", kPadding0);
+    ABSL_RAW_LOG(INFO, "%s", kPadding1);
+  }
+
+  // Verify we can symbolize everything.
+  char buf[512];
+  memset(buf, 0, sizeof(buf));
+  absl::Symbolize(kPadding0, buf, sizeof(buf));
+  EXPECT_STREQ("kPadding0", buf);
+
+  memset(buf, 0, sizeof(buf));
+  absl::Symbolize(kPadding1, buf, sizeof(buf));
+  EXPECT_STREQ("kPadding1", buf);
+
+  // Specify a hint for the executable segment.
+  dl_iterate_phdr(FilterElfHeader, nullptr);
+
+  // Reload at least one page out of kPadding0, kPadding1
+  const char *ptrs[] = {kPadding0, kPadding1};
+
+  for (const char *ptr : ptrs) {
+    const int kMapFlags = MAP_ANONYMOUS | MAP_PRIVATE;
+    void *addr = mmap(nullptr, kPageSize, PROT_READ, kMapFlags, 0, 0);
+    ASSERT_NE(addr, MAP_FAILED);
+
+    // kPadding[0-1] is full of zeroes, so we can remap anywhere within it, but
+    // we ensure there is at least a full page of padding.
+    void *remapped = reinterpret_cast<void *>(
+        reinterpret_cast<uintptr_t>(ptr + kPageSize) & ~(kPageSize - 1ULL));
+
+    const int kMremapFlags = (MREMAP_MAYMOVE | MREMAP_FIXED);
+    void *ret = mremap(addr, kPageSize, kPageSize, kMremapFlags, remapped);
+    ASSERT_NE(ret, MAP_FAILED);
+  }
+
+  // Invalidate the symbolization cache so we are forced to rely on the hint.
+  absl::Symbolize(nullptr, buf, sizeof(buf));
+
+  // Verify we can still symbolize.
+  const char *expected[] = {"kPadding0", "kPadding1"};
+  const size_t offsets[] = {0, kPageSize, 2 * kPageSize, 3 * kPageSize};
+
+  for (int i = 0; i < 2; i++) {
+    for (size_t offset : offsets) {
+      memset(buf, 0, sizeof(buf));
+      absl::Symbolize(ptrs[i] + offset, buf, sizeof(buf));
+      EXPECT_STREQ(expected[i], buf);
+    }
+  }
+}
+
+// Appends std::string(*args->arg) to args->symbol_buf.
+static void DummySymbolDecorator(
+    const absl::debugging_internal::SymbolDecoratorArgs *args) {
+  std::string *message = static_cast<std::string *>(args->arg);
+  strncat(args->symbol_buf, message->c_str(),
+          args->symbol_buf_size - strlen(args->symbol_buf) - 1);
+}
+
+TEST(Symbolize, InstallAndRemoveSymbolDecorators) {
+  int ticket_a;
+  std::string a_message("a");
+  EXPECT_GE(ticket_a = absl::debugging_internal::InstallSymbolDecorator(
+                DummySymbolDecorator, &a_message),
+            0);
+
+  int ticket_b;
+  std::string b_message("b");
+  EXPECT_GE(ticket_b = absl::debugging_internal::InstallSymbolDecorator(
+                DummySymbolDecorator, &b_message),
+            0);
+
+  int ticket_c;
+  std::string c_message("c");
+  EXPECT_GE(ticket_c = absl::debugging_internal::InstallSymbolDecorator(
+                DummySymbolDecorator, &c_message),
+            0);
+
+  char *address = reinterpret_cast<char *>(1);
+  EXPECT_STREQ("abc", TrySymbolize(address++));
+
+  EXPECT_TRUE(absl::debugging_internal::RemoveSymbolDecorator(ticket_b));
+
+  EXPECT_STREQ("ac", TrySymbolize(address++));
+
+  // Cleanup: remove all remaining decorators so other stack traces don't
+  // get mystery "ac" decoration.
+  EXPECT_TRUE(absl::debugging_internal::RemoveSymbolDecorator(ticket_a));
+  EXPECT_TRUE(absl::debugging_internal::RemoveSymbolDecorator(ticket_c));
+}
+
+// Some versions of Clang with optimizations enabled seem to be able
+// to optimize away the .data section if no variables live in the
+// section. This variable should get placed in the .data section, and
+// the test below checks for the existence of a .data section.
+static int in_data_section = 1;
+
+TEST(Symbolize, ForEachSection) {
+  int fd = TEMP_FAILURE_RETRY(open("/proc/self/exe", O_RDONLY));
+  ASSERT_NE(fd, -1);
+
+  std::vector<std::string> sections;
+  ASSERT_TRUE(absl::debugging_internal::ForEachSection(
+      fd, [&sections](const std::string &name, const ElfW(Shdr) &) {
+        sections.push_back(name);
+        return true;
+      }));
+
+  // Check for the presence of common section names.
+  EXPECT_THAT(sections, Contains(".text"));
+  EXPECT_THAT(sections, Contains(".rodata"));
+  EXPECT_THAT(sections, Contains(".bss"));
+  ++in_data_section;
+  EXPECT_THAT(sections, Contains(".data"));
+
+  close(fd);
+}
+
+// x86 specific tests.  Uses some inline assembler.
+extern "C" {
+inline void *ABSL_ATTRIBUTE_ALWAYS_INLINE inline_func() {
+  void *pc = nullptr;
+#if defined(__i386__) || defined(__x86_64__)
+  __asm__ __volatile__("call 1f; 1: pop %0" : "=r"(pc));
+#endif
+  return pc;
+}
+
+void *ABSL_ATTRIBUTE_NOINLINE non_inline_func() {
+  void *pc = nullptr;
+#if defined(__i386__) || defined(__x86_64__)
+  __asm__ __volatile__("call 1f; 1: pop %0" : "=r"(pc));
+#endif
+  return pc;
+}
+
+void ABSL_ATTRIBUTE_NOINLINE TestWithPCInsideNonInlineFunction() {
+#if defined(ABSL_HAVE_ATTRIBUTE_NOINLINE) && \
+    (defined(__i386__) || defined(__x86_64__))
+  void *pc = non_inline_func();
+  const char *symbol = TrySymbolize(pc);
+  ABSL_RAW_CHECK(symbol != nullptr, "TestWithPCInsideNonInlineFunction failed");
+  ABSL_RAW_CHECK(strcmp(symbol, "non_inline_func") == 0,
+                 "TestWithPCInsideNonInlineFunction failed");
+  std::cout << "TestWithPCInsideNonInlineFunction passed" << std::endl;
+#endif
+}
+
+void ABSL_ATTRIBUTE_NOINLINE TestWithPCInsideInlineFunction() {
+#if defined(ABSL_HAVE_ATTRIBUTE_ALWAYS_INLINE) && \
+    (defined(__i386__) || defined(__x86_64__))
+  void *pc = inline_func();  // Must be inlined.
+  const char *symbol = TrySymbolize(pc);
+  ABSL_RAW_CHECK(symbol != nullptr, "TestWithPCInsideInlineFunction failed");
+  ABSL_RAW_CHECK(strcmp(symbol, __FUNCTION__) == 0,
+                 "TestWithPCInsideInlineFunction failed");
+  std::cout << "TestWithPCInsideInlineFunction passed" << std::endl;
+#endif
+}
+}
+
+// Test with a return address.
+void ABSL_ATTRIBUTE_NOINLINE TestWithReturnAddress() {
+#if defined(ABSL_HAVE_ATTRIBUTE_NOINLINE)
+  void *return_address = __builtin_return_address(0);
+  const char *symbol = TrySymbolize(return_address);
+  ABSL_RAW_CHECK(symbol != nullptr, "TestWithReturnAddress failed");
+  ABSL_RAW_CHECK(strcmp(symbol, "main") == 0, "TestWithReturnAddress failed");
+  std::cout << "TestWithReturnAddress passed" << std::endl;
+#endif
+}
+
+#else  // Symbolizer unimplemented
+
+TEST(Symbolize, Unimplemented) {
+  char buf[64];
+  EXPECT_FALSE(absl::Symbolize((void *)(&nonstatic_func), buf, sizeof(buf)));
+  EXPECT_FALSE(absl::Symbolize((void *)(&static_func), buf, sizeof(buf)));
+  EXPECT_FALSE(absl::Symbolize((void *)(&Foo::func), buf, sizeof(buf)));
+}
+
+#endif
+
+int main(int argc, char **argv) {
+  // Make sure kHpageTextPadding is linked into the binary.
+  if (volatile_bool) {
+    ABSL_RAW_LOG(INFO, "%s", kHpageTextPadding);
+  }
+
+#if ABSL_PER_THREAD_TLS
+  // Touch the per-thread variables.
+  symbolize_test_thread_small[0] = 0;
+  symbolize_test_thread_big[0] = 0;
+#endif
+
+  absl::InitializeSymbolizer(argv[0]);
+  testing::InitGoogleTest(&argc, argv);
+
+#ifdef ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE
+  TestWithPCInsideInlineFunction();
+  TestWithPCInsideNonInlineFunction();
+  TestWithReturnAddress();
+#endif
+
+  return RUN_ALL_TESTS();
+}