feat: implement break

CMakeLists.txt

@@ -58,5 +58,9 @@ foreach (TEST_FILE IN LISTS TEST_PROGS)
 		set_tests_properties("progs_compile_${TEST_NAME}" PROPERTIES WILL_FAIL TRUE)
 		set_tests_properties("progs_runtime_${TEST_NAME}" PROPERTIES WILL_FAIL TRUE)
 	endif()
+
+	if (TEST_NAME MATCHES "neg1_")
+		set_tests_properties("progs_runtime_${TEST_NAME}" PROPERTIES WILL_FAIL TRUE)
+	endif()
 endforeach()
 

include/compiler/fzl_parser.h

@@ -19,6 +19,7 @@ typedef enum
   FZL_NODETYPE_FIELD,
   FZL_NODETYPE_CONSTRUCT,
   FZL_NODETYPE_LOOP,
+  FZL_NODETYPE_BREAK,
 
   FZL_NODETYPE_ADD,
   FZL_NODETYPE_SUB,

include/compiler/fzl_token.h

@@ -16,6 +16,7 @@ typedef enum
 
   FZL_TOKTYPE_FOR,   // for
   FZL_TOKTYPE_WHILE, // while
+  FZL_TOKTYPE_BREAK, // break
 
   FZL_TOKTYPE_IF,   // if
   FZL_TOKTYPE_ELSE, // else

src/compiler/checkers/fzl_loop_check.c

@@ -6,42 +6,209 @@
 #include <compiler/utils/fzl_symtable.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <string.h>
+
+ssize_t check_top;
+fzl_nodetype_t check_tree[256];
+
+void ghost_walk_changed(fzl_node_t *node, bool *changed, fzl_sym_t *sym)
+{
+  if (!node || !changed || *changed)
+    return;
+
+  check_tree[check_top++] = node->type;
+
+  switch (node->type)
+  {
+    case FZL_NODETYPE_BREAK:
+    case FZL_NODETYPE_DECLARATION:
+    case FZL_NODETYPE_CONSTRUCT:
+    case FZL_NODETYPE_CLASS:
+    case FZL_NODETYPE_FUNCTION:
+    case FZL_NODETYPE_LITERAL:
+      break;
+
+    case FZL_NODETYPE_UNARY_PLUS:
+    case FZL_NODETYPE_UNARY_MINUS:
+    case FZL_NODETYPE_NOT:
+      ghost_walk_changed(node->unary_op.operand, changed, sym);
+      break;
+
+    case FZL_NODETYPE_ADD:
+    case FZL_NODETYPE_SUB:
+    case FZL_NODETYPE_MUL:
+    case FZL_NODETYPE_DIV:
+    case FZL_NODETYPE_POW:
+    case FZL_NODETYPE_MOD:
+    case FZL_NODETYPE_OR:
+    case FZL_NODETYPE_AND:
+    case FZL_NODETYPE_EQUAL:
+    case FZL_NODETYPE_NEQUAL:
+    case FZL_NODETYPE_LESS:
+    case FZL_NODETYPE_LESS_EQUAL:
+    case FZL_NODETYPE_GREATER:
+    case FZL_NODETYPE_GREATER_EQUAL:
+    case FZL_NODETYPE_ASSIGN:
+      ghost_walk_changed(node->binary_op.left, changed, sym);
+      ghost_walk_changed(node->binary_op.right, changed, sym);
+      break;
+
+    case FZL_NODETYPE_FIELD:
+      ghost_walk_changed(node->memb.parent, changed, sym);
+      ghost_walk_changed(node->memb.field, changed, sym);
+      break;
+
+    case FZL_NODETYPE_RETURN:
+      ghost_walk_changed(node->ret.value, changed, sym);
+      break;
+
+    case FZL_NODETYPE_CONDITIONAL:
+      ghost_walk_changed(node->cond.condition, changed, sym);
+      ghost_walk_changed(node->cond.true_block, changed, sym);
+      ghost_walk_changed(node->cond.else_block, changed, sym);
+      break;
+
+    case FZL_NODETYPE_LOOP:
+      ghost_walk_changed(node->loop.cond, changed, sym);
+      ghost_walk_changed(node->loop.step, changed, sym);
+      ghost_walk_changed(node->loop.body, changed, sym);
+      break;
+
+    case FZL_NODETYPE_BLOCK:
+      for (size_t i = 0; i < node->list.entry_count; i++)
+        ghost_walk_changed(node->list.entries[i], changed, sym);
+      break;
+
+    case FZL_NODETYPE_CALL:
+      ghost_walk_changed(node->call.callee, changed, sym);
+      for (size_t i = 0; i < node->call.args_count; i++)
+        ghost_walk_changed(node->call.args[i], changed, sym);
+      break;
+
+    case FZL_NODETYPE_IDENTIFIER:
+      if (strcmp(node->token->value, sym->name) == 0)
+      {
+        *changed = true;
+      }
+
+      if (*changed)
+      {
+        *changed = false;
+        for (ssize_t i = check_top - 1; i >= 0; i--)
+        {
+          fzl_nodetype_t cur_t = check_tree[i];
+          if (cur_t == FZL_NODETYPE_ADD || cur_t == FZL_NODETYPE_SUB ||
+              cur_t == FZL_NODETYPE_MUL || cur_t == FZL_NODETYPE_DIV ||
+              cur_t == FZL_NODETYPE_POW || cur_t == FZL_NODETYPE_MOD ||
+              cur_t == FZL_NODETYPE_UNARY_MINUS)
+          {
+            *changed = true;
+            break;
+          }
+        }
+      }
+      break;
+  }
+
+  check_tree[--check_top] = 0;
+}
+
+// Whether value changed in loop body
+bool value_is_changed(fzl_node_t *node, fzl_sym_t *sym)
+{
+  if (!node || !sym)
+    return false;
+
+  bool changed = false;
+  check_top    = 0;
+  memset(check_tree, 0, sizeof(check_tree));
+  ghost_walk_changed(node, &changed, sym);
+
+  return changed;
+}
+
+// Try to find symbol in loop condition node
+bool retrieve_cond_sym(fzl_walker_t *walker, fzl_node_t *node, fzl_sym_t *sym)
+{
+  if (!walker || !node)
+    return false;
+
+  switch (node->type)
+  {
+    case FZL_NODETYPE_BREAK:
+    case FZL_NODETYPE_BLOCK:
+    case FZL_NODETYPE_CALL:
+    case FZL_NODETYPE_LITERAL:
+    case FZL_NODETYPE_CONDITIONAL:
+    case FZL_NODETYPE_FUNCTION:
+    case FZL_NODETYPE_RETURN:
+    case FZL_NODETYPE_CLASS:
+    case FZL_NODETYPE_FIELD:
+    case FZL_NODETYPE_CONSTRUCT:
+    case FZL_NODETYPE_LOOP:
+    case FZL_NODETYPE_ASSIGN:
+    case FZL_NODETYPE_DECLARATION:
+      return false;
+
+    case FZL_NODETYPE_UNARY_MINUS:
+    case FZL_NODETYPE_UNARY_PLUS:
+    case FZL_NODETYPE_NOT:
+      return retrieve_cond_sym(walker, node->unary_op.operand, sym);
+
+    case FZL_NODETYPE_ADD:
+    case FZL_NODETYPE_SUB:
+    case FZL_NODETYPE_MUL:
+    case FZL_NODETYPE_DIV:
+    case FZL_NODETYPE_POW:
+    case FZL_NODETYPE_MOD:
+    case FZL_NODETYPE_AND:
+    case FZL_NODETYPE_OR:
+    case FZL_NODETYPE_LESS:
+    case FZL_NODETYPE_LESS_EQUAL:
+    case FZL_NODETYPE_GREATER:
+    case FZL_NODETYPE_GREATER_EQUAL:
+    case FZL_NODETYPE_EQUAL:
+    case FZL_NODETYPE_NEQUAL:
+      if (retrieve_cond_sym(walker, node->binary_op.left, sym))
+        return true;
+      if (retrieve_cond_sym(walker, node->binary_op.right, sym))
+        return true;
+      return false;
+
+    case FZL_NODETYPE_IDENTIFIER:
+    {
+      bool exists;
+      for (ssize_t i = walker->sym_top - 1; i >= 0; i--)
+      {
+        if ((exists = fzl_symt_get(walker->syms[i], (char *)node->token->value,
+                                   sym)))
+          break;
+      }
+      return exists;
+    }
+  }
+
+  return false;
+}
 
 // Check for infinite loop
-bool is_infinite_loop(fzl_walker_t *walker, size_t start_ip, size_t end_ip)
+bool is_infinite_loop(fzl_walker_t *walker, fzl_node_t *node, size_t start_ip,
+                      size_t end_ip)
 {
   if (!walker)
     return false;
 
   end_ip = (end_ip >= walker->op_count) ? (walker->op_count - 1) : end_ip;
 
-  // Can we determine an init block?
-  size_t maybe_init_start = start_ip + 1;
-  size_t maybe_init_end   = start_ip + 6;
-  fzl_const_t *declared   = NULL;
-  for (size_t i = maybe_init_start; i <= maybe_init_end; i++)
-  {
-    if (walker->ops[i] != FZL_OPCODE_STORE)
-      continue;
-
-    declared = &walker->consts->array[walker->ops[i - 1]];
-    break;
-  }
-
-  if (declared)
-  {
   fzl_sym_t sym;
-    bool found = false;
-    for (ssize_t i = walker->sym_top - 1; i >= 0; i--)
-      if ((found = fzl_symt_get(walker->syms[i],
-                                (char *)declared->as.string.chars, &sym)))
-        break;
-
-    if (!found)
-      return false; // suspicious
-
+  bool sym_exists = retrieve_cond_sym(walker, node->loop.cond, &sym);
+  if (sym_exists)
+  {
     if (sym.type >= FZL_TYPE_INT8)
     {
+      bool value_changed = value_is_changed(node, &sym);
+      if (value_changed)
+        return false;
     }
   }
 

src/compiler/fzl_parser.c

@@ -1198,6 +1198,13 @@ fzl_node_t *parse_loop(fzl_parser_t *parser)
   return NULL;
 }
 
+// `break` keyword parsing
+fzl_node_t *parse_break(fzl_parser_t *parser)
+{
+  fzl_token_t *tok = consume(parser);
+  return fzl_mknode(FZL_NODETYPE_BREAK, tok);
+}
+
 // Statement parsing
 fzl_node_t *parse_statement(fzl_parser_t *parser)
 {
@@ -1218,6 +1225,8 @@ fzl_node_t *parse_statement(fzl_parser_t *parser)
     return parse_block(parser);
   else if (is(parser, FZL_TOKTYPE_FOR) || is(parser, FZL_TOKTYPE_WHILE))
     return parse_loop(parser);
+  else if (is(parser, FZL_TOKTYPE_BREAK))
+    res = parse_break(parser);
 
   if (!res)
     res = parse_expression(parser);
@@ -1303,6 +1312,7 @@ void fzl_freeast(fzl_node_t *root)
   {
     switch (root->type)
     {
+      case FZL_NODETYPE_BREAK:
       case FZL_NODETYPE_IDENTIFIER:
       case FZL_NODETYPE_LITERAL:
         break;

src/compiler/fzl_reader.c

@@ -78,6 +78,9 @@ fzl_token_t *parse_name(fzl_reader_t *reader)
   else if (strcmp(value, "while") == 0)
     tok =
         fzl_mktoken(FZL_TOKTYPE_WHILE, l.line, l.col, value, size, l.filename);
+  else if (strcmp(value, "break") == 0)
+    tok =
+        fzl_mktoken(FZL_TOKTYPE_BREAK, l.line, l.col, value, size, l.filename);
   else if (strcmp(value, "new") == 0)
     tok = fzl_mktoken(FZL_TOKTYPE_NEW, l.line, l.col, value, size, l.filename);
   else if (strcmp(value, "fn") == 0)

src/compiler/fzl_walker.c

@@ -14,7 +14,8 @@
 #include <stdlib.h>
 #include <string.h>
 
-extern bool is_infinite_loop(fzl_walker_t *walker, size_t ls, size_t le);
+extern bool is_infinite_loop(fzl_walker_t *walker, fzl_node_t *node, size_t ls,
+                             size_t le);
 
 char *null_name = "<null>";
 char wlast_err[256];
@@ -202,9 +203,45 @@ fzl_walk_res_t walk(fzl_walker_t *walker, fzl_node_t *node)
   {
     switch (node->type)
     {
+      case FZL_NODETYPE_BREAK:
+      {
+        fzl_walk_ctx_t *ctx = walker->ctx;
+        while (ctx)
+        {
+          if (ctx->type == FZL_WALK_CTX_TYPE_LOOP)
+            break;
+
+          ctx = ctx->parent;
+        }
+
+        if (!ctx || ctx->type != FZL_WALK_CTX_TYPE_LOOP)
+        {
+          snprintf(wlast_err, sizeof(wlast_err),
+                   "'%s': usage of 'break' outsude the loop at %ld:%ld",
+                   node->token->filename, node->token->ln, node->token->cn);
+          return (fzl_walk_res_t){.error = true, .error_msg = wlast_err};
+        }
+
+        for (size_t i = walker->sym_top - 1; i > ctx->initial_env_lvl + 1; i--)
+          push_op(walker, FZL_OPCODE_RM_ENVTABLE);
+
+        if (ctx->breaks_remainder <= ctx->breaks_count)
+        {
+          ctx->breaks_remainder *= 2;
+          ctx->breaks =
+              realloc(ctx->breaks, ctx->breaks_remainder * sizeof(size_t));
+        }
+
+        push_op(walker, FZL_OPCODE_JMP);
+        ctx->breaks[ctx->breaks_count++] = walker->op_count;
+        push_word(walker, 0);
+
+        current_res = (fzl_walk_res_t){.type = FZL_TYPE_NULL, .error = false};
+        break;
+      }
+
       // NOTE: add new levels for infinite loop check:
-      //  1. Dead condition (f.e. `while (i < 5)` w/o `i` increment)
-      //  2. Step direction (f.e. `for (; i > 5; i = i - 1)`)
+      //  1. Step direction (f.e. `for (; i > 5; i = i - 1)`)
       case FZL_NODETYPE_LOOP:
       {
         fzl_walk_ctx_t *newctx = nest_ctx(walker, FZL_WALK_CTX_TYPE_LOOP);
@@ -221,6 +258,7 @@ fzl_walk_res_t walk(fzl_walker_t *walker, fzl_node_t *node)
 
         push_op(walker, FZL_OPCODE_MK_ENVTABLE);
         walker->syms[walker->sym_top++] = fzl_mksymt();
+        size_t loop_begin_ip            = walker->op_count;
 
         if (node->loop.init)
         {
@@ -271,12 +309,18 @@ fzl_walk_res_t walk(fzl_walker_t *walker, fzl_node_t *node)
 
         push_op(walker, FZL_OPCODE_JMP);
         push_word(walker, start_ip);
+
+        // backpatch `break`s
+        for (size_t i = 0; i < newctx->breaks_count; i++)
+          walker->ops[newctx->breaks[i]] = walker->op_count;
+
         push_op(walker, FZL_OPCODE_RM_ENVTABLE);
 
         bool is_infinite =
-            is_infinite_loop(walker, start_ip, walker->op_count - 2);
+            is_infinite_loop(walker, node, loop_begin_ip, walker->op_count - 2);
         if (is_infinite)
         {
+          free(newctx->breaks);
           snprintf(wlast_err, sizeof(wlast_err),
                    "'%s': infinite loop detected at %ld:%ld",
                    node->token->filename, node->token->ln, node->token->cn);
@@ -286,10 +330,6 @@ fzl_walk_res_t walk(fzl_walker_t *walker, fzl_node_t *node)
         for (size_t i = walker->sym_top - 1; i > newctx->initial_env_lvl; i--)
           fzl_freesymt(walker->syms[--walker->sym_top]);
 
-        // backpatch `break`s
-        for (size_t i = 0; i < newctx->breaks_count; i++)
-          walker->ops[newctx->breaks[i]] = walker->op_count - 1;
-
         free(newctx->breaks);
         if (!fin_ctx(walker))
         {

src/vm/fzl_vm.c

@@ -4,6 +4,7 @@
 #include <common/fzl_value.h>
 #include <compiler/utils/fzl_const_pool.h>
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -13,6 +14,11 @@
 #include <vm/fzl_vm_object.h>
 
 char last_err[256];
+size_t last_jmp_ip = 0;
+
+// NOTE: add `--max-iter` option for limit
+size_t max_iter_limit    = 100000;
+size_t total_jmp_on_same = 0;
 
 static char *expect_hdr = "FZL\0\1";
 
@@ -667,7 +673,22 @@ int fzl_vm_run(fzl_vm_t *vm)
           return -1;
         }
         uint64_t jmp_ip = vm->ops[++vm->ip];
+        if (jmp_ip == last_jmp_ip)
+          total_jmp_on_same++;
+        else
+          total_jmp_on_same = 0;
+
+        if (total_jmp_on_same > max_iter_limit)
+        {
+          snprintf(last_err, sizeof(last_err),
+                   "runtime error - exceeded max loop jumps (infinite loop?)\n"
+                   "If you thinks there's mistake, change jumps limit with "
+                   "--max-iter=N");
+          return -1;
+        }
+
         vm->ip      = jmp_ip - 1;
+        last_jmp_ip = jmp_ip;
         break;
       }
 

tests/programs/neg1_infinite_for.fzs

@@ -0,0 +1,3 @@
+for (int i = 0; i < 5; i = i + 0)
+{}
+

tests/programs/neg_infinite_for.fzs

@@ -1,3 +0,0 @@
-for (int i = 0; i < 5; i = i - 1)
-{}
-