added locals/globals, fixed nested loops

README.md

@@ -12,7 +12,23 @@ Run the command line tool using:
 
 `c2logic filename -O optimization_level`
 
-where `filename` is a string and `optimization_level` is an integer.
+where `filename` is a string and `optimization_level` is an optional integer
+Optimization Level:
+
+0. completely unoptimized
+1. the default
+    - modify variables without using a temporary
+2. turns on some potentially unsafe optimizations
+    - augmented assignment and pre/postincrement/decrement don't modify \_\_rax
+    - returning from main becomes equivalent to `end`
+
+Locals are rewritten as _<varname>_<func_name>. Globals are unchanged.
+
+Special Variables:
+
+-   \_\_rax: similar to x86 rax
+-   \_\_rbx: stores left hand side of binary ops to avoid clobbering by the right side
+-   \__retaddr_\*: stores return address of func call
 
 When developing your script, you can include `c2logic/builtins.h` located in the python include directory(location depends on system, mine is at `~/.local/include/python3.8/`)
 

c2logic/compiler.py

@@ -1,4 +1,5 @@
 import site
+import dataclasses
 from dataclasses import dataclass
 
 from pycparser import c_ast, parse_file
@@ -16,8 +17,20 @@ from .instructions import (
 class Function():
 	name: str
 	params: list
-	instructions: list
+	
+	instructions: list = dataclasses.field(default_factory=list)
+	locals: list = dataclasses.field(init=False)
+	start: int = dataclasses.field(init=False)
+	
+	def __post_init__(self):
+		self.locals = self.params[:]
+		self.start = None
+		self.called = False
+
+@dataclass
+class Loop():
 	start: int
+	end_jumps: list = dataclasses.field(default_factory=list)
 
 """
 @dataclass
@@ -27,33 +40,37 @@ class Variable():
 """
 
 class Compiler(c_ast.NodeVisitor):
-	"""special variables:
-	__rax: similar to x86 rax
-	__rbx: stores left hand side of binary ops to avoid clobbering by the right side
-	__retaddr: stores return address of func call
-	"""
 	def __init__(self, opt_level=0):
 		self.opt_level = opt_level
 		self.functions: dict = None
 		self.curr_function: Function = None
-		self.loop_start: int = None
-		self.loop_end_jumps: list = None
-		#self.cond_jump_offset: int = None
+		self.globals: list = None
+		self.loops: list = None
+		#self.loop_start: int = None
+		#self.loop_end_jumps: list = None
+		self.loop_end: int = None
 	
 	def compile(self, filename: str):
 		self.functions = {}
 		self.curr_function = None
-		self.loop_start = None
-		self.cond_jump_offset = None
+		self.globals = []
+		self.loops = []
+		#self.loop_start = None
+		#self.loop_end_jumps = None
+		self.loop_end = None
 		ast = parse_file(
 			filename, use_cpp=True, cpp_args=["-I", site.getuserbase() + "/include/python3.8"]
 		)
 		self.visit(ast)
-		#TODO actually handle functions properly
+		
 		init_call = FunctionCall("main")
-		preamble = [Set("__retaddr_main", "2"), init_call, End()]
+		if self.opt_level >= 2:
+			preamble = [init_call]
+		else:
+			preamble = [Set("__retaddr_main", "2"), init_call, End()]
 		
 		offset = len(preamble)
+		
 		#set function starts
 		for function in self.functions.values():
 			function.start = offset
@@ -89,6 +106,13 @@ class Compiler(c_ast.NodeVisitor):
 	def curr_offset(self):
 		return len(self.curr_function.instructions) - 1
 	
+	def get_varname(self, varname):
+		if varname in self.curr_function.locals:
+			return f"_{varname}_{self.curr_function.name}"
+		elif varname not in self.globals:
+			raise NameError(f"Unknown variable {varname}")
+		return varname
+	
 	def can_avoid_indirection(self, var="__rax"):
 		top = self.peek()
 		return self.opt_level >= 1 and isinstance(top, Set) and top.dest == var
@@ -114,17 +138,26 @@ class Compiler(c_ast.NodeVisitor):
 			self.push(RelativeJump(None, JumpCondition("==", "__rax", "0")))
 	
 	def start_loop(self, cond):
-		self.loop_start = self.curr_offset() + 1
+		self.loops.append(Loop(self.curr_offset() + 1))
 		self.visit(cond)
 		self.push_body_jump()
-		self.loop_end_jumps = [self.curr_offset()]  # also used for breaks
+		self.loops[-1].end_jumps = [self.curr_offset()]  # also used for breaks
 	
 	def end_loop(self):
-		self.push(RelativeJump(self.loop_start, JumpCondition.always))
-		for offset in self.loop_end_jumps:
-			self.curr_function.instructions[offset].offset = self.curr_offset() + 1
-		self.loop_start = None
-		self.loop_end_jumps = None
+		loop = self.loops.pop()
+		self.push(RelativeJump(loop.start, JumpCondition.always))
+		self.loop_end = self.curr_offset() + 1
+		for offset in loop.end_jumps:
+			self.curr_function.instructions[offset].offset = self.loop_end
+	
+	def push_ret(self):
+		if self.opt_level >= 2 and self.curr_function.name == "main":
+			top = self.peek()
+			if isinstance(top, Set) and top.dest == "__rax":
+				self.pop()
+			self.push(End())
+		else:
+			self.push(Return(self.curr_function.name))
 	
 	def optimize_psuedofunc_args(self, args):
 		if self.opt_level >= 1:
@@ -141,25 +174,32 @@ class Compiler(c_ast.NodeVisitor):
 		func_decl = node.decl.type
 		params = [param_decl.name for param_decl in func_decl.args.params]
 		
-		self.curr_function = Function(func_name, params, [], None)
+		self.curr_function = Function(func_name, params)
 		self.visit(node.body)
 		#implicit return
-		#needed unconditionally in case loop/if body is at end of function
-		self.push(Set("__rax", "null"))
-		self.push(Return(self.curr_function.name))
+		#needed if loop/if body is at end of function or hasn't returned yet
+		if self.loop_end == self.curr_offset() + 1 or not isinstance(self.peek(), Return):
+			self.push(Set("__rax", "null"))
+			self.push_ret()
 		self.functions[func_name] = self.curr_function
 	
 	def visit_Decl(self, node):
 		if isinstance(node.type, TypeDecl):  # variable declaration
 			#TODO fix local/global split
+			varname = node.name
+			if self.curr_function is None:  # globals
+				self.globals.append(varname)
+			else:
+				self.curr_function.locals.append(varname)
+				varname = f"_{varname}_{self.curr_function.name}"
 			if node.init is not None:
 				self.visit(node.init)
-				self.set_to_rax(node.name)
+				self.set_to_rax(varname)
 		elif isinstance(node.type, FuncDecl):
 			if node.name not in builtins + func_unary_ops + func_binary_ops:
 				#create placeholder function for forward declarations
 				self.functions[node.name] = Function(
-					node.name, [param_decl.name for param_decl in node.type.args.params], [], None
+					node.name, [param_decl.name for param_decl in node.type.args.params]
 				)
 		elif isinstance(node.type, Struct):
 			if node.type.name != "MindustryObject":
@@ -173,7 +213,7 @@ class Compiler(c_ast.NodeVisitor):
 	
 	def visit_Assignment(self, node):
 		self.visit(node.rvalue)
-		varname = node.lvalue.name
+		varname = self.get_varname(node.lvalue.name)
 		if node.op == "=":  #normal assignment
 			self.set_to_rax(varname)
 		else:  #augmented assignment(+=,-=,etc)
@@ -182,12 +222,17 @@ class Compiler(c_ast.NodeVisitor):
 				self.push(BinaryOp(varname, varname, self.pop().src, node.op[:-1]))
 			else:
 				self.push(BinaryOp(varname, varname, "__rax", node.op[:-1]))
+			if self.opt_level < 2:
+				self.push(Set("__rax", varname))
 	
 	def visit_Constant(self, node):  # literals
 		self.push(Set("__rax", node.value))
 	
 	def visit_ID(self, node):  # identifier
-		self.push(Set("__rax", node.name))
+		varname = node.name
+		if varname not in self.functions:
+			varname = self.get_varname(varname)
+		self.push(Set("__rax", varname))
 	
 	def visit_BinaryOp(self, node):
 		self.visit(node.left)
@@ -204,12 +249,14 @@ class Compiler(c_ast.NodeVisitor):
 	def visit_UnaryOp(self, node):
 		if node.op == "p++" or node.op == "p--":  #postincrement/decrement
 			varname = node.expr.name
-			self.push(Set("__rax", varname))
+			if self.opt_level < 2:
+				self.push(Set("__rax", varname))
 			self.push(BinaryOp(varname, varname, "1", node.op[1]))
 		elif node.op == "++" or node.op == "--":
 			varname = node.expr.name
 			self.push(BinaryOp(varname, varname, "1", node.op[0]))
-			self.push(Set("__rax", varname))
+			if self.opt_level < 2:
+				self.push(Set("__rax", varname))
 		elif node.op == "!":
 			self.visit(node.expr)
 			if self.opt_level >= 1 and isinstance(self.peek(), BinaryOp):
@@ -266,14 +313,14 @@ class Compiler(c_ast.NodeVisitor):
 	
 	def visit_Break(self, node):
 		self.push(RelativeJump(None, JumpCondition.always))
-		self.loop_end_jumps.append(self.curr_offset())
+		self.loops[-1].end_jumps.append(self.curr_offset())
 	
 	def visit_Continue(self, node):
-		self.push(RelativeJump(self.loop_start, JumpCondition.always))
+		self.push(RelativeJump(self.loops[-1].start, JumpCondition.always))
 	
 	def visit_Return(self, node):
 		self.visit(node.expr)
-		self.push(Return(self.curr_function.name))
+		self.push_ret()
 	
 	def visit_FuncCall(self, node):
 		name = node.name.name
@@ -371,7 +418,7 @@ class Compiler(c_ast.NodeVisitor):
 				raise ValueError(f"{name} is not a function")
 			for param, arg in zip(func.params, args):
 				self.visit(arg)
-				self.set_to_rax(param)
+				self.set_to_rax(f"{param}_{name}")
 			self.push(Set("__retaddr_" + name, self.curr_offset() + 3))
 			self.push(FunctionCall(name))
 	

c2logic/instructions.py

@@ -48,6 +48,8 @@ class JumpCondition:
 	def from_binaryop(cls, binop: BinaryOp):
 		return cls(binop.op, binop.left, binop.right)
 	
+	always: "JumpCondition" = None
+	
 	def __str__(self):
 		return f"{condition_ops[self.op]} {self.left} {self.right}"
 

examples/func_calls.c

@@ -1,12 +1,12 @@
 #include "c2logic/builtins.h"
 extern struct MindustryObject message1;
-/*double factorial(int x) {
+double factorial(int x) {
 	int ret = 1;
 	for (int i = 2; i <= x; i++) {
-		ret *= x;
+		ret *= i;
 	}
 	return ret;
-}*/
+}
 
 double a(void) {
 	return 5;
@@ -14,8 +14,8 @@ double a(void) {
 void main(void) {
 	printd(a());
 	print("\n");
-	/*printd(factorial(4));
+	printd(factorial(4));
 	print("\n");
-	printd(factorial(5));*/
+	printd(factorial(5));
 	printflush(message1);
 }