add VM

vm.c

@@ -1 +1,93 @@
 #include "vm.h"
+
+#include "runtime.h"
+#include "util.h"
+
+#define INIT_STACK_CAP 256
+
+typedef struct Stack {
+	Value *mem;
+	size_t len, cap;
+} Stack;
+
+static Stack stack_make(void);
+static void stack_term(Stack *s);
+static void stack_fit(Stack *s, size_t idx);
+
+static Stack stack_make(void) {
+	Stack s;
+	s.mem = xmalloc(sizeof(Value) * INIT_STACK_CAP);
+	s.cap = INIT_STACK_CAP;
+	s.len = 0;
+	return s;
+}
+
+static void stack_term(Stack *s) {
+	free(s->mem);
+}
+
+static void stack_fit(Stack *s, size_t idx) {
+	size_t size = idx+1;
+	if (size > s->cap) {
+		s->mem = xrealloc(s->mem, sizeof(Value) * (size + (s->cap *= 2)));
+	}
+}
+
+static Value *irparam_to_val(Stack *s, IRParam *v) {
+	if (v->kind == IRParamLiteral)
+		return &v->Literal;
+	else if (v->kind == IRParamAddr)
+		return &s->mem[v->Addr];
+	else
+		ASSERT_UNREACHED();
+}
+
+void run(const IRToks *ir, const BuiltinFunc *builtin_funcs) {
+	Stack s = stack_make();
+	for (size_t i = 0; i < ir->len;) {
+		IRTok *instr = &ir->toks[i];
+		switch (instr->instr) {
+			case IRSet:
+			case IRNeg:
+				stack_fit(&s, instr->Unary.addr);
+				s.mem[instr->Unary.addr] = eval_unary(instr->instr, irparam_to_val(&s, &instr->Unary.val));
+				break;
+			case IRAdd:
+			case IRSub:
+			case IRDiv:
+			case IRMul:
+				stack_fit(&s, instr->Arith.addr);
+				s.mem[instr->Arith.addr] = eval_arith(instr->instr,
+					irparam_to_val(&s, &instr->Arith.lhs),
+					irparam_to_val(&s, &instr->Arith.rhs)
+				);
+				break;
+			case IRJmp:
+				i = instr->Jmp.iaddr;
+				continue;
+			case IRJnz:
+				if (is_nonzero(irparam_to_val(&s, &instr->CJmp.condition))) {
+					i = instr->Jmp.iaddr;
+					continue;
+				}
+				break;
+			case IRCallInternal: {
+				const BuiltinFunc *f = &builtin_funcs[instr->CallI.fid];
+				Value *args = xmalloc(sizeof(Value) * f->n_args);
+				for (size_t i = 0; i < f->n_args; i++)
+					args[i] = *irparam_to_val(&s, &instr->CallI.args[i]);
+
+				stack_fit(&s, instr->CallI.ret_addr);
+				s.mem[instr->CallI.ret_addr] = f->func(args);
+
+				free(args);
+				break;
+			}
+			default:
+				ASSERT_UNREACHED();
+		}
+
+		i++;
+	}
+	stack_term(&s);
+}