GetCurrentOsStackTraceExceptTop (both the method of UnitTestImpl and …

…the wrapper function in gtest.cc) rely on the fact that the inner call is not getting optimized.

This CL annotates them with the appropriate attributes.

PiperOrigin-RevId: 425663217
Change-Id: Ib9ec2a69a7dd98d37640b56d4d7798572da66669

googletest/include/gtest/internal/gtest-port.h

@@ -789,6 +789,20 @@ typedef struct _RTL_CRITICAL_SECTION GTEST_CRITICAL_SECTION;
 # define GTEST_NO_INLINE_
 #endif
 
+#if defined(__clang__)
+// Nested ifs to avoid triggering MSVC warning.
+#if __has_attribute(disable_tail_calls)
+// Ask the compiler not to perform tail call optimization inside
+// the marked function.
+#define GTEST_NO_TAIL_CALL_ __attribute__((disable_tail_calls))
+#endif
+#elif __GNUC__
+#define GTEST_NO_TAIL_CALL_ \
+  __attribute__((optimize("no-optimize-sibling-calls")))
+#else
+#define GTEST_NO_TAIL_CALL_
+#endif
+
 // _LIBCPP_VERSION is defined by the libc++ library from the LLVM project.
 #if !defined(GTEST_HAS_CXXABI_H_)
 # if defined(__GLIBCXX__) || (defined(_LIBCPP_VERSION) && !defined(_MSC_VER))

googletest/src/gtest-internal-inl.h

@@ -623,7 +623,8 @@ class GTEST_API_ UnitTestImpl {
   // For example, if Foo() calls Bar(), which in turn calls
   // CurrentOsStackTraceExceptTop(1), Foo() will be included in the
   // trace but Bar() and CurrentOsStackTraceExceptTop() won't.
-  std::string CurrentOsStackTraceExceptTop(int skip_count) GTEST_NO_INLINE_;
+  std::string CurrentOsStackTraceExceptTop(int skip_count)
+      GTEST_NO_INLINE_ GTEST_NO_TAIL_CALL_;
 
   // Finds and returns a TestSuite with the given name.  If one doesn't
   // exist, creates one and returns it.

googletest/src/gtest.cc

@@ -6292,8 +6292,8 @@ void UnitTestImpl::UnshuffleTests() {
 // For example, if Foo() calls Bar(), which in turn calls
 // GetCurrentOsStackTraceExceptTop(..., 1), Foo() will be included in
 // the trace but Bar() and GetCurrentOsStackTraceExceptTop() won't.
-std::string GetCurrentOsStackTraceExceptTop(UnitTest* /*unit_test*/,
-                                            int skip_count) {
+GTEST_NO_INLINE_ GTEST_NO_TAIL_CALL_ std::string
+GetCurrentOsStackTraceExceptTop(UnitTest* /*unit_test*/, int skip_count) {
   // We pass skip_count + 1 to skip this wrapper function in addition
   // to what the user really wants to skip.
   return GetUnitTestImpl()->CurrentOsStackTraceExceptTop(skip_count + 1);