Always enable proper symbolize implementation on Windows (#257)

absl/debugging/BUILD.bazel

@@ -70,8 +70,14 @@ cc_library(
 cc_test(
     name = "symbolize_test",
     srcs = ["symbolize_test.cc"],
-    copts = ABSL_TEST_COPTS,
-    linkopts = ABSL_DEFAULT_LINKOPTS,
+    copts = ABSL_TEST_COPTS + select({
+        "//absl:windows": ["/Z7"],
+        "//conditions:default": [],
+    }),
+    linkopts = ABSL_DEFAULT_LINKOPTS + select({
+        "//absl:windows": ["/DEBUG"],
+        "//conditions:default": [],
+    }),
     deps = [
         ":stack_consumption",
         ":symbolize",

absl/debugging/CMakeLists.txt

@@ -62,6 +62,9 @@ absl_cc_test(
     "symbolize_test.cc"
   COPTS
     ${ABSL_TEST_COPTS}
+    $<$<BOOL:${MSVC}>:-Z7>
+  LINKOPTS
+    $<$<BOOL:${MSVC}>:-DEBUG>
   DEPS
     absl::stack_consumption
     absl::symbolize

absl/debugging/symbolize.cc

@@ -16,12 +16,9 @@
 
 #if defined(ABSL_INTERNAL_HAVE_ELF_SYMBOLIZE)
 #include "absl/debugging/symbolize_elf.inc"
-#elif defined(_WIN32) && defined(_DEBUG)
-// The Windows Symbolizer only works in debug mode. Note that _DEBUG
-// is the macro that defines whether or not MS C-Runtime debug info is
-// available. Note that the PDB files containing the debug info must
-// also be available to the program at runtime for the symbolizer to
-// work.
+#elif defined(_WIN32)
+// The Windows Symbolizer only works if PDB files containing the debug info
+// are available to the program at runtime.
 #include "absl/debugging/symbolize_win32.inc"
 #else
 #include "absl/debugging/symbolize_unimplemented.inc"

absl/debugging/symbolize_test.cc

@@ -35,10 +35,29 @@
 
 using testing::Contains;
 
+#ifdef _WIN32
+#define ABSL_SYMBOLIZE_TEST_NOINLINE __declspec(noinline)
+#else
+#define ABSL_SYMBOLIZE_TEST_NOINLINE ABSL_ATTRIBUTE_NOINLINE
+#endif
+
 // 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(); }
+ABSL_SYMBOLIZE_TEST_NOINLINE void nonstatic_func() {
+  // The next line makes this a unique function to prevent the compiler from
+  // folding identical functions together.
+  volatile int x = __LINE__;
+  static_cast<void>(x);
+  ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
+}
+
+ABSL_SYMBOLIZE_TEST_NOINLINE static void static_func() {
+  // The next line makes this a unique function to prevent the compiler from
+  // folding identical functions together.
+  volatile int x = __LINE__;
+  static_cast<void>(x);
+  ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
+}
 }  // extern "C"
 
 struct Foo {
@@ -46,7 +65,11 @@ struct Foo {
 };
 
 // A C++ method that should have a mangled name.
-void ABSL_ATTRIBUTE_NOINLINE Foo::func(int) {
+ABSL_SYMBOLIZE_TEST_NOINLINE void Foo::func(int) {
+  // The next line makes this a unique function to prevent the compiler from
+  // folding identical functions together.
+  volatile int x = __LINE__;
+  static_cast<void>(x);
   ABSL_BLOCK_TAIL_CALL_OPTIMIZATION();
 }
 
@@ -449,7 +472,7 @@ void ABSL_ATTRIBUTE_NOINLINE TestWithReturnAddress() {
 #endif
 }
 
-#elif defined(_WIN32) && defined(_DEBUG)
+#elif defined(_WIN32)
 
 TEST(Symbolize, Basics) {
   EXPECT_STREQ("nonstatic_func", TrySymbolize((void *)(&nonstatic_func)));

absl/debugging/symbolize_win32.inc

@@ -57,9 +57,8 @@ bool Symbolize(const void *pc, char *out, int out_size) {
   if (out_size <= 0) {
     return false;
   }
-  std::aligned_storage<sizeof(SYMBOL_INFO) + MAX_SYM_NAME,
-                       alignof(SYMBOL_INFO)>::type buf;
-  SYMBOL_INFO *symbol = reinterpret_cast<SYMBOL_INFO *>(&buf);
+  alignas(SYMBOL_INFO) char buf[sizeof(SYMBOL_INFO) + MAX_SYM_NAME];
+  SYMBOL_INFO *symbol = reinterpret_cast<SYMBOL_INFO *>(buf);
   symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
   symbol->MaxNameLen = MAX_SYM_NAME;
   if (!SymFromAddr(process, reinterpret_cast<DWORD64>(pc), nullptr, symbol)) {