Stricter enforcement of branching at the end of a basic block. Add modifier to blocks so they can be labelled as functions

Author: simon816

assembler.py

@@ -255,7 +255,7 @@ def resolve_ref(self, type, value):
     def callinsn(self, dest):
         if isinstance(dest, VisibleFunction):
             return Invoke(dest, None, None)
-        return Call(dest)
+        return Branch(dest)
 
     def get_src_dest(self, src, dest):
         src, dest = self.resolve_ref(*src), self.resolve_ref(*dest)

cmd_ir/core.py

@@ -475,6 +475,7 @@ def end(self):
         assert not self.finished
         for block in self.blocks:
             block.end()
+        print("%s is closed: %s" % (self, self.is_closed()))
         self._finished = True
 
     def get_func_table(self):
@@ -523,6 +524,7 @@ def variables_finalized(self):
         stackvars = self.add_entry_exit()
         self.configure_parameters(bool(stackvars))
         if self.is_closed():
+            self._entryblock.force = True
             for insn in self._exitblock.insns:
                 self._entryblock.add(insn)
             self._exitblock.insns = []
@@ -533,7 +535,7 @@ def variables_finalized(self):
 
     def add_entry_exit(self):
         from .variables import LocalVariable, NbtOffsetVariable
-        from .instructions import PushNewStackFrame, PopStack, Call
+        from .instructions import PushNewStackFrame, PopStack, Branch
         # sorted from head to tail of stack
         vars = sorted([var.var for var in self.scope.values() \
                 if isinstance(var, LocalVariable) \
@@ -549,7 +551,7 @@ def add_entry_exit(self):
                                                          in vars[::-1])))
             self._exitblock.add(PopStack())
         # Always branch to real entry point
-        self._entryblock.add(Call(self.blocks[0]))
+        self._entryblock.add(Branch(self.blocks[0]))
         return vars
 
     def add_advancement_revoke(self, event):
@@ -574,6 +576,8 @@ def __init__(self, name, func):
         self._func = func
         self.needs_success_tracker = False
         self.defined = False
+        self.is_function = False
+        self.force = False
         self._use = 0
 
     def usage(self):
@@ -585,6 +589,9 @@ def reset(self):
     def use_count(self):
         return self._use
 
+    def set_is_function(self):
+        self.is_function = True
+
     @property
     def global_name(self):
         return self._func._name + '/' + self._name
@@ -597,14 +604,19 @@ def end(self):
 
     def is_terminated(self):
         assert self.defined
+        if self.is_function:
+            return True
         if not self.insns:
             return False
         return self.insns[-1].terminator()
 
     def add(self, insn):
-        from .instructions import Return, Call
+        if not self.force and self.insns and self.insns[-1].terminator():
+            assert False, "Block %s is terminated by %s. Tried adding %s" % (
+                self, self.insns[-1], insn)
+        from .instructions import Return, Branch
         if isinstance(insn, Return):
-            return super().add(Call(self._func._exitblock))
+            return super().add(Branch(self._func._exitblock))
         return super().add(insn)
 
     def writeout(self, temp_gen):

cmd_ir/core_types.py

@@ -185,15 +185,20 @@ class BlockType(Resolvable, NativeType):
 
     def __init__(self, block_id):
         self.block_id = block_id
+        self.nbt = None
         self.props = {}
 
     def add_prop(self, prop, value):
         self.props[prop] = value
 
+    def set_nbt(self, nbt):
+        self.nbt = nbt
+
     def resolve(self, scope):
         props = ','.join(['%s=%s' % (key, self.props[key]) \
                           for key in sorted(self.props.keys())])
-        return '%s%s' % (self.block_id, '[%s]' % props if props else '')
+        nbt = self.nbt.resolve(scope) if self.nbt is not None else ''
+        return '%s%s%s' % (self.block_id, '[%s]' % props if props else '', nbt)
 
 class ItemType(Resolvable, NativeType):
 
@@ -209,5 +214,5 @@ def resolve(self, scope):
         if self.nbt_props:
             from .nbt import NBTCompound
             nbt = NBTCompound(self.nbt_props.items())
-            props = '[%s]' % nbt.resolve(scope)
+            props = nbt.resolve(scope)
         return '%s%s' % (self.item_id, props)

cmd_ir/grammar.lark

@@ -10,7 +10,9 @@ function: "function" FUNC_NAME "{" function_body "}"
 
 function_body: preamble? block*
 
-block: LABEL NEWLINE instruction*
+block: block_modifier? LABEL NEWLINE instruction*
+
+block_modifier: "[" WORD "]"
 
 instruction: ( assign_insn | normal_insn ) NEWLINE
 
@@ -44,6 +46,7 @@ ASSIGN_OP: "=" | "+=" | "-=" | "*=" | "/=" | "%=" | "><" | "<" | ">"
 %import common.SIGNED_FLOAT
 %import common.WS
 %import common.NEWLINE
+%import common.WORD
 
 %ignore WS
 COMMENT: "#" /[^\n]/*