From 21bdfeafcc830bfdf8936c3387f665fa67d34633 Mon Sep 17 00:00:00 2001
From: Ian Petersen <ispeters@gmail.com>
Date: Sat, 31 Aug 2024 20:44:23 -0700
Subject: [PATCH] Start reading return and frame addresses with MSVC

---
 include/unifex/config.hpp              | 25 +++++++++++++++++++++++++
 include/unifex/tracing/async_stack.hpp | 18 +++++++-----------
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/include/unifex/config.hpp b/include/unifex/config.hpp
index 9457b1d5..95d48327 100644
--- a/include/unifex/config.hpp
+++ b/include/unifex/config.hpp
@@ -308,4 +308,29 @@
 #  else
 #    define UNIFEX_NO_ASYNC_STACKS 0
 #  endif
+#elif UNIFEX_NO_ASYNC_STACKS
+// make sure the truthy value is 1
+#  undef UNIFEX_NO_ASYNC_STACKS
+#  define UNIFEX_NO_ASYNC_STACKS 1
+#else
+// make sure the falsey value is 0
+#  undef UNIFEX_NO_ASYNC_STACKS
+#  define UNIFEX_NO_ASYNC_STACKS 0
 #endif  // !defined(UNIFEX_NO_ASYNC_STACKS)
+
+#if UNIFEX_HAS_BUILTIN(__builtin_return_address)
+#  define UNIFEX_RETURN_ADDRESS __builtin_return_address(0)
+#elif defined(_MSC_VER)
+#  define UNIFEX_RETURN_ADDRESS _ReturnAddress()
+#else
+#  define UNIFEX_RETURN_ADDRESS nullptr
+#endif
+
+#if UNIFEX_HAS_BUILTIN(__builtin_frame_address)
+#  define UNIFEX_FRAME_ADDRESS __builtin_frame_address(0)
+#elif defined(_MSC_VER)
+// not sure, yet, that this is right, but it's where we're starting
+#  define UNIFEX_FRAME_ADDRESS _AddressOfReturnAddress()
+#else
+#  define UNIFEX_FRAME_ADDRESS nullptr
+#endif
diff --git a/include/unifex/tracing/async_stack.hpp b/include/unifex/tracing/async_stack.hpp
index ca52d394..e8b287fd 100644
--- a/include/unifex/tracing/async_stack.hpp
+++ b/include/unifex/tracing/async_stack.hpp
@@ -22,6 +22,11 @@
 #include <cassert>
 #include <cstdint>
 
+#if defined(_MSC_VER)
+// needed for _ReturnAddress() and _AddressOfReturnAddress()
+#include <intrin.h>
+#endif
+
 #include <unifex/detail/prologue.hpp>
 
 namespace unifex {
@@ -273,13 +278,8 @@ struct instruction_ptr final {
   // Generally a function that uses this macro should be declared FOLLY_NOINLINE
   // to prevent this returning surprising results in cases where the function
   // is inlined.
-#if UNIFEX_HAS_BUILTIN(__builtin_return_address)
-  static constexpr instruction_ptr
-  read_return_address(void* p = __builtin_return_address(0)) noexcept {
-#else
   static constexpr instruction_ptr
-  read_return_address(void* p = nullptr) noexcept {
-#endif
+  read_return_address(void* p = UNIFEX_RETURN_ADDRESS) noexcept {
     return instruction_ptr{p};
   }
 
@@ -311,12 +311,8 @@ struct frame_ptr {
   // Generally a function that uses this macro should be declared FOLLY_NOINLINE
   // to prevent this returning surprising results in cases where the function
   // is inlined.
-#if UNIFEX_HAS_BUILTIN(__builtin_frame_address)
   static constexpr frame_ptr
-  read_frame_pointer(void* p = __builtin_frame_address(0)) noexcept {
-#else
-  static constexpr frame_ptr read_frame_pointer(void* p = nullptr) noexcept {
-#endif
+  read_frame_pointer(void* p = UNIFEX_FRAME_ADDRESS) noexcept {
     return frame_ptr{p};
   }