create distinct interned string type

Interned strings are used pervasively, so it's a good idea to add a
layer of type safety to differentiate them from general cstrs and avoid
potential bugs from comparing non-interned and interned strings. Not
that that's happened so far that I can remember, but it could.

I'm 90% sure it's legal to alias `struct {char c;}` pointers with `char`
pointers. This specific typedef gives type safety but with a simple
one-way `internstr -> const char *` typecast (with `&istr->c`).
Converting the other way around is more intentional: a straight up cast
`(internstr)cstr` which sticks out as unchecked and probably wrong, or
calling the intern(cstr) function, which is the right way.

1 files changed, 1 insertions, 1 deletions

diff --git a/ir/intrin.c b/ir/intrin.c
index 2ef826c..53e29fc 100644
--- a/ir/intrin.c
+++ b/ir/intrin.c
@@ -24,7 +24,7 @@ intrin(struct block *blk, int *curi, enum intrin in, struct arg *args, int narg,
          /* memcpy */
          *args[1].ty = *args[0].ty = mktyperef(cls2type(KPTR));
          insertinstr(blk, (*curi)++, mkarginstr(cls2type(cls), mkintcon(cls, td->siz)));
-         *this = mkinstr(Ocall, 0, mksymref("memcpy", 1), this->r);
+         *this = mkinstr(Ocall, 0, mksymref(intern("memcpy"), 1), this->r);
          calltab.p[this->r.i].narg = 3;
          calltab.p[this->r.i].ret = cls2type(0);
          return 0;