From e53c63568669d30ef8dc5850083fcd36d9d3fc07 Mon Sep 17 00:00:00 2001
From: Eyal Rozenberg <eyalroz1@gmx.com>
Date: Fri, 27 Sep 2024 11:35:15 +0300
Subject: [PATCH] Regards #679: Added demangling support using NVIDIA's
 (nearly-hidden) libcufilt

---
 CMakeLists.txt                      | 16 +++++-
 src/cuda/api.hpp                    |  1 +
 src/cuda/api/demangle.hpp           | 76 +++++++++++++++++++++++++++++
 src/cuda/api/detail/unique_span.hpp |  7 +++
 4 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 src/cuda/api/demangle.hpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 43be50b1..a7d29ff2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,9 +32,14 @@ if(CUDAToolkit_VERSION VERSION_GREATER_EQUAL 12.4)
 		endif()
 	endforeach()
 endif()
+if (NOT TARGET CUDA::cufilt)
+	_CUDAToolkit_find_and_add_import_lib(cufilt)
+endif()
+
 set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
 
 
+
 set(targets runtime-and-driver nvtx rtc fatbin)
 set(prefixed-targets "")
 set(caw_namespace "cuda-api-wrappers")
@@ -75,7 +80,7 @@ foreach(wrapper_lib ${targets})
 		WINDOWS_EXPORT_ALL_SYMBOLS ON
 	)
 endforeach()
-add_library("${caw_namespace}::driver-and-runtime" ALIAS caw_runtime-and-driver)
+add_library("cuda-api-wrappers::driver-and-runtime" ALIAS caw_runtime-and-driver)
 target_link_libraries(caw_rtc INTERFACE cuda-api-wrappers::runtime-and-driver CUDA::nvrtc)
 if(CUDAToolkit_VERSION VERSION_GREATER_EQUAL 11.1)
 	if (TARGET CUDA::nvptxcompiler)
@@ -99,6 +104,15 @@ if(CUDAToolkit_VERSION VERSION_GREATER_EQUAL 12.4)
 	else()
 		message(WARNING "Could not locate a valid NVIDIA fatbin creator target or library file")
 	endif()
+
+	if (TARGET CUDA::cufilt)
+		target_link_libraries(caw_runtime-and-driver INTERFACE CUDA::cufilt)
+	elseif(EXISTS "${CUDA_cufilt_LIBRARY}")
+		target_link_libraries(caw_runtime-and-driver INTERFACE "${CUDA_cufilt_LIBRARY}")
+	else()
+		message(WARNING "Could not locate the cufilt demangling library")
+	endif()
+
 endif()
 
 target_link_libraries(caw_fatbin INTERFACE cuda-api-wrappers::runtime-and-driver)
diff --git a/src/cuda/api.hpp b/src/cuda/api.hpp
index 51af11f0..35d3c44e 100644
--- a/src/cuda/api.hpp
+++ b/src/cuda/api.hpp
@@ -36,6 +36,7 @@
 #include "api/event.hpp"
 #include "api/kernel.hpp"
 #include "api/module.hpp"
+#include "api/demangle.hpp"
 #if CUDA_VERSION >= 12000
 #include "api/library.hpp"
 #include "api/kernels/in_library.hpp"
diff --git a/src/cuda/api/demangle.hpp b/src/cuda/api/demangle.hpp
new file mode 100644
index 00000000..52a07554
--- /dev/null
+++ b/src/cuda/api/demangle.hpp
@@ -0,0 +1,76 @@
+/**
+ * @file
+ *
+ * @brief Functions related to mangling & demangling identifiers
+ *
+ */
+#ifndef CUDA_API_WRAPPERS_MANGLING_HPP_
+#define CUDA_API_WRAPPERS_MANGLING_HPP_
+
+#include "detail/span.hpp"
+#include "detail/unique_span.hpp"
+#include <nv_decode.h>
+
+namespace cuda {
+
+namespace detail_ {
+
+using mangle_status_t = int;
+
+void validate_mangling_status(int status)
+{
+	switch (status) {
+	// 0 is fine
+	case -1: throw ::std::runtime_error("Memory allocation failure by __cu_demangle for a demangled CUDA identifier");
+	case -2: throw ::std::invalid_argument("Mangled identifier passed for demangling was invalid");
+	case -3: throw ::std::invalid_argument("Validation of one of the input arguments for a __cu_demangle() call failed");
+	}
+	return;
+}
+
+// TODO: Assuming the length _does_ include the trailing '\0'
+inline char* demangle(const char* mangled_identifier, char* buffer, size_t& allocated_size)
+{
+	int status;
+	char* result = __cu_demangle(mangled_identifier, buffer, &allocated_size, &status);
+	validate_mangling_status(status);
+	return result;
+}
+
+inline unique_span<char> demangle(const char* mangled_identifier)
+{
+	size_t allocated_size { 0 };
+	auto demangled = demangle(mangled_identifier, nullptr, allocated_size);
+#ifndef NDEBUG
+	if (allocated_size <= 1) {
+		throw std::logic_error("Invalid allocation size returned by __cu_demangle()");
+	}
+#endif
+	return unique_span<char>{demangled, allocated_size - 1, c_free_deleter<char> };
+}
+
+
+} // namespace detail_
+
+inline unique_span<char> demangle(const char* mangled_identifier)
+{
+	return detail_::demangle(mangled_identifier);
+}
+
+template<typename T>
+T demangle_as(const char* mangled_identifier)
+{
+	auto demangled = detail_::demangle(mangled_identifier);
+	return { demangled.data(), demangled.data() + demangled.size() };
+}
+
+template<>
+inline ::std::string demangle_as<::std::string>(const char* mangled_identifier)
+{
+	auto demangled = detail_::demangle(mangled_identifier);
+	return { demangled.data(), demangled.size() };
+}
+
+} // namespace cuda
+
+#endif // CUDA_API_WRAPPERS_MANGLING_HPP_
diff --git a/src/cuda/api/detail/unique_span.hpp b/src/cuda/api/detail/unique_span.hpp
index f04b60d1..65c0d5e0 100644
--- a/src/cuda/api/detail/unique_span.hpp
+++ b/src/cuda/api/detail/unique_span.hpp
@@ -177,6 +177,13 @@ inline void default_span_deleter(span<T> sp)
 	delete[] sp.data();
 }
 
+template <typename T>
+inline void c_free_deleter(span<T> sp)
+{
+	::std::free(sp.data());
+}
+
+
 } // namespace detail_