Reland of Add function to trace stack using frame pointers.

base/debug/stack_trace_unittest.cc

Index: base/debug/stack_trace_unittest.cc
diff --git a/base/debug/stack_trace_unittest.cc b/base/debug/stack_trace_unittest.cc
index 9abedba6bafd91160989fb718cebc78b4fafbdf6..e716bf740d81cbd795e4b879eaf1096e0acd91e3 100644
--- a/base/debug/stack_trace_unittest.cc
+++ b/base/debug/stack_trace_unittest.cc
@@ -238,5 +238,56 @@ TEST_F(StackTraceTest, itoa_r) {
 }
 #endif  // defined(OS_POSIX) && !defined(OS_ANDROID)
 
+#if HAVE_TRACE_STACK_FRAME_POINTERS
+
+template <size_t Depth>
+void NOINLINE ExpectStackFramePointers(const void** frames,
+                                       size_t max_depth) {
+  code_start:
+  // Calling __builtin_frame_address() forces compiler to emit
+  // frame pointers, even if they are not enabled.
+  EXPECT_NE(nullptr, __builtin_frame_address(0));
+  ExpectStackFramePointers<Depth - 1>(frames, max_depth);
+
+  constexpr size_t frame_index = Depth - 1;
+  const void* frame = frames[frame_index];
+  EXPECT_GE(frame, &&code_start) << "For frame at index " << frame_index;
+  EXPECT_LE(frame, &&code_end) << "For frame at index " << frame_index;
+  code_end: return;
+}
+
+template <>
+void NOINLINE ExpectStackFramePointers<1>(const void** frames,
+                                          size_t max_depth) {
+  code_start:
+  // Calling __builtin_frame_address() forces compiler to emit
+  // frame pointers, even if they are not enabled.
+  EXPECT_NE(nullptr, __builtin_frame_address(0));
+  size_t count = TraceStackFramePointers(frames, max_depth, 0);
+  ASSERT_EQ(max_depth, count);
+
+  const void* frame = frames[0];
+  EXPECT_GE(frame, &&code_start) << "For the top frame";
+  EXPECT_LE(frame, &&code_end) << "For the top frame";
+  code_end: return;
+}
+
+#if defined(MEMORY_SANITIZER)
+// The test triggers use-of-uninitialized-value errors on MSan bots.
+// This is expected because we're walking and reading the stack, and
+// sometimes we read fp / pc from the place that previously held
+// uninitialized value.
+#define MAYBE_TraceStackFramePointers DISABLED_TraceStackFramePointers
+#else
+#define MAYBE_TraceStackFramePointers TraceStackFramePointers
+#endif
+TEST_F(StackTraceTest, MAYBE_TraceStackFramePointers) {
+  constexpr size_t kDepth = 5;
+  const void* frames[kDepth];
+  ExpectStackFramePointers<kDepth>(frames, kDepth);
+}
+
+#endif  // HAVE_TRACE_STACK_FRAME_POINTERS
+
 }  // namespace debug
 }  // namespace base