From 696be6aacd9bdb044ef4a521795add790aadcd32 Mon Sep 17 00:00:00 2001
From: Nekotekina <nekotekina@gmail.com>
Date: Wed, 9 Jun 2021 19:05:25 +0300
Subject: [PATCH] Implement fmt::ensure (assert-like with formatted message) +
 fmt::tie

Arguments should be provided via fmt::tie() due to some limitations.
Allow to specify simple message (non-formatting) for plain ::ensure().
Remove redundant function for narrow error.
---
 Utilities/StrFmt.cpp | 13 +++-------
 Utilities/StrFmt.h   | 62 ++++++++++++++++++++++++++++++++++++++++++++
 rpcs3/main.cpp       |  2 +-
 rpcs3/util/types.hpp | 16 +++++++-----
 4 files changed, 76 insertions(+), 17 deletions(-)

diff --git a/Utilities/StrFmt.cpp b/Utilities/StrFmt.cpp
index c66d3cad01..082ae05339 100644
--- a/Utilities/StrFmt.cpp
+++ b/Utilities/StrFmt.cpp
@@ -313,17 +313,10 @@ void fmt_class_string<src_loc>::format(std::string& out, u64 arg)
 
 namespace fmt
 {
-	[[noreturn]] void raw_verify_error(const src_loc& loc)
+	[[noreturn]] void raw_verify_error(const src_loc& loc, const char8_t* msg)
 	{
-		std::string out{"Verification failed"};
-		fmt::append(out, "%s", loc);
-		thread_ctrl::emergency_exit(out);
-	}
-
-	[[noreturn]] void raw_narrow_error(const src_loc& loc)
-	{
-		std::string out{"Narrowing error"};
-		fmt::append(out, "%s", loc);
+		std::string out;
+		fmt::append(out, "%s%s", msg ? msg : u8"Verification failed", loc);
 		thread_ctrl::emergency_exit(out);
 	}
 
diff --git a/Utilities/StrFmt.h b/Utilities/StrFmt.h
index dae5725119..e3bb916753 100644
--- a/Utilities/StrFmt.h
+++ b/Utilities/StrFmt.h
@@ -293,4 +293,66 @@ namespace fmt
 
 	template <typename CharT, usz N, typename... Args>
 	throw_exception(const CharT(&)[N], const Args&...) -> throw_exception<CharT, N, Args...>;
+
+	// Helper template: pack format variables
+	template <typename Arg = void, typename... Args>
+	struct tie
+	{
+		// Universal reference
+		std::add_rvalue_reference_t<Arg> arg;
+
+		tie<Args...> next;
+
+		// Store only references, unveil op is postponed
+		tie(Arg&& arg, Args&&... args) noexcept
+			: arg(std::forward<Arg>(arg))
+			, next(std::forward<Args>(args)...)
+		{
+		}
+
+		using type = std::remove_cvref_t<Arg>;
+
+		// Storage for fmt_unveil (deferred initialization)
+		decltype(fmt_unveil<type>::get(std::declval<Arg>())) value;
+
+		void init(u64 to[])
+		{
+			value = fmt_unveil<type>::get(arg);
+			to[0] = value;
+			next.init(to + 1);
+		}
+	};
+
+	template <>
+	struct tie<void>
+	{
+		void init(u64 to[]) const
+		{
+			// Isn't really null terminated, this value has no meaning
+			to[0] = 0;
+		}
+	};
+
+	template <typename... Args>
+	tie(Args&&... args) -> tie<Args...>;
+
+	// Ensure with formatting
+	template <typename T, typename CharT, usz N, typename... Args>
+	decltype(auto) ensure(T&& arg, const CharT(&fmt)[N], tie<Args...> args,
+		u32 line = __builtin_LINE(),
+		u32 col = __builtin_COLUMN(),
+		const char* file = __builtin_FILE(),
+		const char* func = __builtin_FUNCTION()) noexcept
+	{
+		if (std::forward<T>(arg)) [[likely]]
+		{
+			return std::forward<T>(arg);
+		}
+
+		// Prepare u64 array
+		u64 data[sizeof...(Args) + 1];
+		args.init(data);
+
+		raw_throw_exception({line, col, file, func}, reinterpret_cast<const char*>(fmt), type_info_v<std::remove_cvref_t<Args>...>, +data);
+	}
 }
diff --git a/rpcs3/main.cpp b/rpcs3/main.cpp
index 3c06b26a1b..859d0fc2a6 100644
--- a/rpcs3/main.cpp
+++ b/rpcs3/main.cpp
@@ -419,7 +419,7 @@ int main(int argc, char** argv)
 	}
 #endif
 
-	ensure(thread_ctrl::is_main());
+	ensure(thread_ctrl::is_main(), "Not main thread");
 
 	// Initialize TSC freq (in case it isn't)
 	static_cast<void>(utils::get_tsc_freq());
diff --git a/rpcs3/util/types.hpp b/rpcs3/util/types.hpp
index 736236a785..e814bb2bf5 100644
--- a/rpcs3/util/types.hpp
+++ b/rpcs3/util/types.hpp
@@ -802,6 +802,12 @@ struct const_str_t<umax>
 		const char* chars2;
 	};
 
+	const_str_t()
+		: size(0)
+		, chars(nullptr)
+	{
+	}
+
 	template <usz N>
 	constexpr const_str_t(const char8_t(&a)[N])
 		: size(N - 1)
@@ -845,12 +851,11 @@ struct src_loc
 
 namespace fmt
 {
-	[[noreturn]] void raw_verify_error(const src_loc& loc);
-	[[noreturn]] void raw_narrow_error(const src_loc& loc);
+	[[noreturn]] void raw_verify_error(const src_loc& loc, const char8_t* msg);
 }
 
 template <typename T>
-constexpr decltype(auto) ensure(T&& arg,
+constexpr decltype(auto) ensure(T&& arg, const_str msg = const_str(),
 	u32 line = __builtin_LINE(),
 	u32 col = __builtin_COLUMN(),
 	const char* file = __builtin_FILE(),
@@ -861,7 +866,7 @@ constexpr decltype(auto) ensure(T&& arg,
 		return std::forward<T>(arg);
 	}
 
-	fmt::raw_verify_error({line, col, file, func});
+	fmt::raw_verify_error({line, col, file, func}, msg);
 }
 
 // narrow() function details
@@ -946,8 +951,7 @@ template <typename To = void, typename From, typename = decltype(static_cast<To>
 	// Narrow check
 	if (narrow_impl<From, To>::test(value)) [[unlikely]]
 	{
-		// Pack value as formatting argument
-		fmt::raw_narrow_error({line, col, file, func});
+		fmt::raw_verify_error({line, col, file, func}, u8"Narrowing error");
 	}
 
 	return static_cast<To>(value);