From b7f6c641f1989c03f678ff4c059ac0e8213db456 Mon Sep 17 00:00:00 2001
From: Rangi <35663410+Rangi42@users.noreply.github.com>
Date: Sat, 19 Sep 2026 16:07:10 -0400
Subject: [PATCH] Define more debug options for `make develop` (#2124)

---
 CMakeLists.txt  | 12 ++++++++++--
 Makefile        |  4 +++-
 src/version.cpp | 19 ++++++++++++++-----
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c1337533..30d106f5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,14 +52,22 @@ endif()
 if(SANITIZERS)
   if(MSVC)
     message(STATUS "ASan enabled")
-    add_compile_options(/fsanitize=address) # Note that this shouldn't be passed to the linker.
+    add_compile_options(/fsanitize=address /sdl) # Note that this shouldn't be passed to the linker.
+    add_definitions(/_MSVC_STL_HARDENING=1 /_MSVC_STL_DESTRUCTOR_TOMBSTONES=1 /D_ITERATOR_DEBUG_LEVEL=2)
   else() # We assume a GNU-like compiler.
     message(STATUS "ASan and UBSan enabled")
     set(SAN_FLAGS -fsanitize=address -fsanitize=undefined
                   -fsanitize=float-divide-by-zero)
     add_compile_options(${SAN_FLAGS})
     add_link_options(${SAN_FLAGS})
-    add_definitions(-D_GLIBCXX_ASSERTIONS -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG)
+    # Consider using `_GLIBCXX_DEBUG_BACKTRACE` (and `-lstdc++exp`) if unable to debug locally.
+    add_definitions(-D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC -D_GLIBCXX_SANITIZE_VECTOR
+                    -D_GLIBCXX_VERBOSE_ASSERT
+                    # This enables debug-mode checks for `std::string`s, but stdlibc++ says
+                    # "this is unsupported and not guaranteed to work", so removing it may be fine.
+                    # https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug_mode_semantics.html
+                    -D_GLIBCXX_EXTERN_TEMPLATE=0
+                    -D_LIBCPP_DEBUG -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG)
     # A non-zero optimization level is desired even in debug mode (especially for Clang),
     # and the two codegen flags improve the sanitizers' backtraces, but we want the user to
     # be able to override these easily so we put them first.
diff --git a/Makefile b/Makefile
index 859b134e..1f6b2f14 100644
--- a/Makefile
+++ b/Makefile
@@ -225,7 +225,9 @@ develop:
 		-Wformat=2 -Wformat-overflow=2 -Wformat-truncation=1 \
 		-Wno-format-nonliteral -Wno-strict-overflow -Wno-unused-but-set-variable \
 		-Wno-type-limits -Wno-tautological-constant-out-of-range-compare -Wvla \
-		-D_GLIBCXX_ASSERTIONS -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG \
+		-D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC -D_GLIBCXX_SANITIZE_VECTOR \
+		-D_GLIBCXX_VERBOSE_ASSERT -D_GLIBCXX_EXTERN_TEMPLATE=0 \
+		-D_LIBCPP_DEBUG -D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG \
 		-fsanitize=address -fsanitize=undefined -fsanitize=float-divide-by-zero" \
 		CXXFLAGS="-ggdb3 -Og -fno-omit-frame-pointer -fno-optimize-sibling-calls"
 
diff --git a/src/version.cpp b/src/version.cpp
index e64e2060..9e44d95d 100644
--- a/src/version.cpp
+++ b/src/version.cpp
@@ -14,13 +14,22 @@
 #if !defined(NDEBUG) && defined(__SANITIZE_ADDRESS__) && !defined(__APPLE__)
 extern "C" {
 	char const *__asan_default_options(void) {
-		return "detect_leaks=1"
-		       ":detect_stack_use_after_return=1"
+		return ":check_initialization_order=1"
 		       ":detect_invalid_pointer_pairs=2"
-		       ":check_initialization_order=1"
+		       ":detect_leaks=1"
+		       ":detect_stack_use_after_return=1"
+		       // ":fast_unwind_on_malloc=0" // Enable this if ASan outputs bad backtraces
+		       ":print_legend=0"
 		       ":strict_init_order=1"
-		       ":strict_string_checks=1"
-		       ":print_legend=0";
+		       ":strict_string_checks=1";
+	}
+}
+#endif
+
+#if !defined(NDEBUG) && defined(__SANITIZE_UNDEFINED__)
+extern "C" {
+	char const *__ubsan_default_options(void) {
+		return "print_stacktrace=1";
 	}
 }
 #endif