Initial commit

ast.lua

@@ -0,0 +1,237 @@
+local ETypes = require"etype"
+
+local function generic_visitor(node, pre_callback, post_callback)
+	if pre_callback then pre_callback(node) end
+	
+	for k, v in ipairs(node.children) do
+		generic_visitor(v, pre_callback, post_callback)
+	end
+	
+	if post_callback then post_callback(node) end
+end
+
+local ASTNode = {}
+function ASTNode:__index(k)
+	if k == "add" then
+		return function(self, child)
+			table.insert(self.children, child)
+			return #self.children
+		end
+	elseif k == "generic_visitor" then
+		return generic_visitor
+	end
+	
+	local under = rawget(self, "_" .. k)
+	if under then
+		return self.children[under]
+	end
+end
+function deep_copy(item)
+	if type(item) == "table" then
+		local ret = {}
+		for k, v in pairs(item) do
+			ret[deep_copy(k)] = deep_copy(v)
+		end
+		return setmetatable(ret, getmetatable(item))
+	end
+	return item
+end
+function ASTNode:deep_copy()
+	return deep_copy(self)
+end
+local DEPTH = 0
+function ASTNode:__tostring()
+	local specials = {}
+	local special_keys = {}
+	for k, v in pairs(self) do
+		if k ~= "children" and k ~= "kind" then
+			table.insert(specials, {k, v})
+			special_keys[v] = true
+		end
+	end
+	table.sort(specials, function(a, b) return a[1] < b[1] end)
+		
+	local children = {"(", self.kind}
+	
+	for _, sp in pairs(specials) do
+		table.insert(children, " ")
+		if sp[1]:sub(1, 1) == "_" then
+			table.insert(children, sp[1]:sub(2) .. "=" .. tostring(self.children[sp[2]]))
+		else
+			table.insert(children, sp[1] .. "=" .. tostring(sp[2]))
+		end
+	end
+	
+	DEPTH = DEPTH + 1
+	for k, v in ipairs(self.children) do
+		if not special_keys[k] then
+			table.insert(children, "\n")
+			table.insert(children, string.rep(" ", DEPTH))
+			table.insert(children, tostring(v))
+		end
+	end
+	DEPTH = DEPTH - 1
+	
+	children[#children + 1] = ")"
+	return table.concat(children)
+end
+
+local NEXT_VREG_ID = 0
+local VReg = {}
+VReg.__index = VReg
+function VReg:__tostring()
+	return tostring(self.id)
+end
+local function new_vreg(name, etype)
+	assert(name)
+	assert(not etype or ETypes.is(etype))
+	NEXT_VREG_ID = NEXT_VREG_ID + 1
+	return setmetatable({name = name, etype = etype, id = NEXT_VREG_ID}, VReg)
+end
+
+local function node(kind)
+	return setmetatable({kind = kind, children = {}}, ASTNode)
+end
+
+local function is(n)
+	return type(n) == "table" and getmetatable(n) == ASTNode
+end
+
+local function root()
+	return node("root")
+end
+
+local function decl(name, expr, export)
+	local n = node("decl")
+	n.name = name
+	n._expr = n:add(expr)
+	n.export = export
+	return n
+end
+
+local function binop(etype, a, op, b)
+	assert(not etype or ETypes.is(etype))
+	assert(is(a) and is(b))
+	
+	local n = node("expr-binop")
+	n.etype = etype
+	n.op = op
+	n._a = n:add(a)
+	n._b = n:add(b)
+	return n
+end
+
+local function unop(etype, op, a)
+	assert(not etype or ETypes.is(etype))
+	assert(is(a))
+	
+	local n = node("expr-unop")
+	n.etype = etype
+	n.op = op
+	n._a = n:add(a)
+	return n
+end
+
+local function int(etype, value)
+	assert(not etype or etype.kind == "scalar" or etype.kind == "pointer")
+	
+	local n = node("expr-int")
+	n.etype = etype
+	n.value = value
+	return n
+end
+
+local function unknown(etype)
+	local n = node("expr-unknown")
+	n.etype = etype
+	return n
+end
+
+local function func(etype)
+	assert(not etype or etype.kind == "func")
+	
+	local n = node("expr-func")
+	n.etype = etype
+	return n
+end
+
+local function array(etype, length)
+	assert(etype)
+	
+	local n = node("expr-array")
+	n.etype = etype
+	n.length = length
+	return n
+end
+
+local function var(etype, vreg)
+	assert(ETypes.is(etype) or (etype == nil and vreg.etype and ETypes.is(vreg.etype)))
+	
+	local n = node("expr-var")
+	n.etype = etype or vreg.etype
+	n.vreg = vreg
+	return n
+end
+
+local function stringh(value)
+	local n = node("expr-string")
+	n.value = value
+	n.etype = ETypes.string()
+	return n
+end
+
+local function assign(dest, src)
+	assert(dest and src)
+	
+	local n = node("stmt-assign")
+	n._dest = n:add(dest)
+	n._src = n:add(src)
+	return n
+end
+
+local function label(label_name)
+	local n = node("stmt-label")
+	n.name = label_name
+	return n
+end
+
+local function jump(condition, label_name)
+	local n = node("stmt-jump")
+	n._condition = n:add(condition)
+	n.target = label_name
+	return n
+end
+
+local function ret(value)
+	local n = node("stmt-return")
+	n._value = n:add(value)
+	return n
+end
+
+local function cast(what, etype)
+	if etype == nil then
+		return what
+	end
+	
+	if what.etype == etype then
+		return what
+	end
+	
+	if what.kind == "expr-string" and etype.kind == "scalar" then
+		assert(#what.value * 8 == etype.bits, "String length does not match integer size")
+		
+		local val = 0
+		for j = #what.value, 1, -1 do
+			val = val * 256 + what.value:sub(j, j):byte()
+		end
+		
+		return int(etype, val)
+	end
+	
+	local n = node("expr-cast")
+	n._child = n:add(what)
+	n.etype = etype
+	return n
+end
+
+return {ASTNode = ASTNode, VReg = new_vreg, node = node, root = root, decl = decl, int = int, binop = binop, unop = unop, func = func, array = array, var = var, assign = assign, label = label, jump = jump, ret = ret, unknown = unknown, string = stringh, cast = cast}