Do away with memcpy/memset/memcmp

Now everything is either explicitly a rep thing, or explicitly some
other small run of reasonably efficient instructions. No library calls
or function call overhead of any kind. Code size remains nice and small.

Ban a few other bad libc functions while we're at it. More can be added
later if we decide that's a useful idea.

This will require some discipline and workarounds to cope with Clang's
tendency to shove mem* calls in places you don't want them even when you
tell it not to. Well, c'est la vie.

I'm a little nervous that the __builtin_memmove() usage in shuntvars()
could still one day emit actual library calls. It appears we're not
importing memmove() from anywhere at the moment, though. So I guess it's
good enough for now.

Also I had to get rid of alloca() in con_.c but that was kind of bad
anyway, so that's fine.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/l4d1democompat.c b/src/l4d1democompat.c
index a6d418f..735215c 100644
--- a/src/l4d1democompat.c
+++ b/src/l4d1democompat.c
@@ -127,8 +127,9 @@ static inline ReadDemoHeader_func find_ReadDemoHeader(const uchar *insns) {
 static inline void *find_midpoint(ReadDemoHeader_func ReadDemoHeader) {
 	uchar *insns = (uchar *)ReadDemoHeader;
 	for (uchar *p = insns; p - insns < 128;) {
+		const u64 HL2DEMO = 0x4F4D4544324C48; // "HL2DEMO\0" ascii, little-endian
 		if (p[0] == X86_PUSHIW && p[5] == X86_PUSHEBX && p[6] == X86_CALL &&
-				!memcmp(mem_loadptr(p + 1), "HL2DEMO", 7)) {
+				!mem_loadu64(mem_loadptr(p + 1)) == HL2DEMO) {
 			return p + 11;
 		}
 		NEXT_INSN(p, "ReadDemoHeader hook midpoint");