[master] 7574ac639 vgc: Assert on ctx->method also for custom subs

[Nils Goroll]

commit 7574ac63950e7adb963da2a085090c6e8349ae66
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Sat Jan 30 21:09:19 2021 +0100

    vgc: Assert on ctx->method also for custom subs
    
    Improve safety by asserting that a sub is never called from a context
    which is not allowed as per its okmask.
    
    This is to ensure correctness of our compile- and runtime-checks.

diff --git a/lib/libvcc/vcc_compile.c b/lib/libvcc/vcc_compile.c
index f3a87aa39..20aac191d 100644
--- a/lib/libvcc/vcc_compile.c
+++ b/lib/libvcc/vcc_compile.c
@@ -171,6 +171,8 @@ static void
 vcc_EmitProc(struct vcc *tl, struct proc *p)
 {
 	struct vsb *vsbm;
+	unsigned mask;
+	const char *maskcmp;
 
 	AN(p->okmask);
 	AZ(VSB_finish(p->cname));
@@ -178,6 +180,14 @@ vcc_EmitProc(struct vcc *tl, struct proc *p)
 	AZ(VSB_finish(p->body));
 	AN(p->sym);
 
+	if (p->method) {
+		mask = p->method->bitval;
+		maskcmp = "==";
+	} else {
+		mask = p->okmask;
+		maskcmp = "&";
+	}
+
 	Fh(tl, 1, "vcl_func_f %s;\n", VSB_data(p->cname));
 	Fh(tl, 1, "const struct vcl_sub sub_%s[1] = {{\n",
 	   VSB_data(p->cname));
@@ -201,15 +211,12 @@ vcc_EmitProc(struct vcc *tl, struct proc *p)
 	   p->method && p->method->bitval & VCL_MET_TASK_H ?
 	   "v_dont_optimize " : "");
 	Fc(tl, 1, "%s(VRT_CTX)\n{\n", VSB_data(p->cname));
-	if (p->method) {
-		vsbm = VSB_new_auto();
-		AN(vsbm);
-		vcc_vcl_met2c(vsbm, p->method->bitval);
-		AZ(VSB_finish(vsbm));
-		Fc(tl, 1, "  assert(ctx->method == (%s));\n",
-		   VSB_data(vsbm));
-		VSB_destroy(&vsbm);
-	}
+	vsbm = VSB_new_auto();
+	AN(vsbm);
+	vcc_vcl_met2c(vsbm, mask);
+	AZ(VSB_finish(vsbm));
+	Fc(tl, 1, "  assert(ctx->method %s (%s));\n", maskcmp, VSB_data(vsbm));
+	VSB_destroy(&vsbm);
 	Fc(tl, 1, "%s\n%s}\n", VSB_data(p->prologue), VSB_data(p->body));
 	VSB_destroy(&p->body);
 	VSB_destroy(&p->prologue);