Rewrite and redesign codegen and feature system

Also switch to somewhat proper C23 flags while we're at it.

This is a huge change. It took me forever, in between being really busy.
Sorry about that. But the good news is I'm now free to start integrating
the various patches that have accumulated since last release. Well, at
least in between still being really busy. Gotta manage expectations.

The main benefit of introducing GAMESPECIFIC() is that features
that don't apply to a particular game no longer show up *at all*, and
less time is wasted on init. It also enables a cool optimisation wherein
unnecessary REQUIRE_GAMEDATA() checks can elided at compile time
whenever the gamedata is known up-front to always exist in supported
games.

The DEF_FEAT_CVAR macro family meanwhile makes it easier to manage the
lifecycle of cvars/ccmds, with less manual registering, unhiding and
such.

Originally I was going to try and just hack these features into the
existing codegen abomination, but it just got too terrible. This rewrite
should make it easier to continue tweaking codegen behaviour in future.
It also has slightly better error messages.

1 files changed, 19 insertions, 21 deletions

diff --git a/src/fastfwd.c b/src/fastfwd.c
index e287770..7378b04 100644
--- a/src/fastfwd.c
+++ b/src/fastfwd.c
@@ -1,6 +1,6 @@
 /*
  * Copyright © 2023 Matthew Wozniak <sirtomato999@gmail.com>
- * Copyright © 2024 Michael Smith <mikesmiffy128@gmail.com>
+ * Copyright © 2025 Michael Smith <mikesmiffy128@gmail.com>
  * Copyright © 2023 Willian Henrique <wsimanbrazil@yahoo.com.br>
  *
  * Permission to use, copy, modify, and/or distribute this software for any
@@ -35,6 +35,10 @@
 #include "x86util.h"
 
 FEATURE()
+// currently only used for l4d quick reset stuff, and conflicts with SPT's
+// tas_pause hook. so, disable for non-L4D games for now, to be polite.
+// TODO(compat): come up with a real solution for this if/when required
+GAMESPECIFIC(L4Dbased)
 REQUIRE_GAMEDATA(vtidx_RunFrame)
 REQUIRE_GAMEDATA(vtidx_Frame)
 REQUIRE_GAMEDATA(vtidx_GetRealTime)
@@ -174,79 +178,73 @@ static void *find_floatcall(void *func, int fldcnt, const char *name) {
 				}
 				NEXT_INSN(p, name);
 			}
-			return false;
+			return 0;
 		}
 next:	NEXT_INSN(p, name);
 	}
 	return 0;
 }
 
-PREINIT {
-	// currently only used for l4d quick reset stuff, and conflicts with SPT's
-	// tas_pause hook. so, disable for non-L4D games for now, to be polite.
-	// TODO(compat): come up with a real solution for this if/when required
-	return GAMETYPE_MATCHES(L4Dbased);
-}
-
 INIT {
 	void *hldsapi = factory_engine("VENGINE_HLDS_API_VERSION002", 0);
 	if_cold (!hldsapi) {
 		errmsg_errorx("couldn't find HLDS API interface");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	void *enginetool = factory_engine("VENGINETOOL003", 0);
 	if_cold (!enginetool) {
 		errmsg_errorx("missing engine tool interface");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	// behold: the greatest pointer chase of all time
 	realtime = find_float((*(void ***)enginetool)[vtidx_GetRealTime]);
 	if_cold (!realtime) {
 		errmsg_errorx("couldn't find realtime variable");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	host_frametime = find_float((*(void ***)enginetool)[vtidx_HostFrameTime]);
 	if_cold (!host_frametime) {
 		errmsg_errorx("couldn't find host_frametime variable");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	void *eng = find_eng((*(void ***)hldsapi)[vtidx_RunFrame]);
 	if_cold (!eng) {
 		errmsg_errorx("couldn't find eng global object");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	void *func;
 	if_cold (!(func = find_HostState_Frame((*(void ***)eng)[vtidx_Frame]))) {
 		errmsg_errorx("couldn't find HostState_Frame function");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	if_cold (!(func = find_FrameUpdate(func))) {
 		errmsg_errorx("couldn't find FrameUpdate function");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	if_cold (!(func = find_floatcall(func, GAMETYPE_MATCHES(L4D2_2147plus) ?
 			2 : 1, "CHostState::State_Run"))) {
 		errmsg_errorx("couldn't find State_Run function");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	if_cold (!(func = find_floatcall(func, 1, "Host_RunFrame"))) {
 		errmsg_errorx("couldn't find Host_RunFrame function");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	if_cold (!(func = find_floatcall(func, 1, "_Host_RunFrame"))) {
 		errmsg_errorx("couldn't find _Host_RunFrame");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	if_cold (!find_Host_AccumulateTime(func)) {
 		errmsg_errorx("couldn't find Host_AccumulateTime");
-		return false;
+		return FEAT_INCOMPAT;
 	}
 	orig_Host_AccumulateTime = (Host_AccumulateTime_func)hook_inline(
 			(void *)orig_Host_AccumulateTime, (void *)hook_Host_AccumulateTime);
 	if_cold (!orig_Host_AccumulateTime) {
 		errmsg_errorsys("couldn't hook Host_AccumulateTime function");
+		return FEAT_FAIL;
 	}
-	return true;
+	return FEAT_OK;
 }
 
 END {