From f431b7a693f73810b05c5f4f049de0df8ac50ac4 Mon Sep 17 00:00:00 2001
From: "Wolfgang (Blub) Bumiller" <blub@speed.at>
Date: Sun, 25 Nov 2012 21:40:26 +0100
Subject: [PATCH] Support codegen of ast_label and ast_goto in any order

---
 ast.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 ast.h | 24 ++++++++++++++++++-
 2 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/ast.c b/ast.c
index 16141b8..a73c586 100644
--- a/ast.c
+++ b/ast.c
@@ -807,11 +807,37 @@ ast_label* ast_label_new(lex_ctx ctx, const char *name)
 
     self->name    = util_strdup(name);
     self->irblock = NULL;
+    self->gotos   = NULL;
 
     return self;
 }
 
 void ast_label_delete(ast_label *self)
+{
+    mem_d((void*)self->name);
+    vec_free(self->gotos);
+    ast_expression_delete((ast_expression*)self);
+    mem_d(self);
+}
+
+void ast_label_register_goto(ast_label *self, ast_goto *g)
+{
+    vec_push(self->gotos, g);
+}
+
+ast_goto* ast_goto_new(lex_ctx ctx, const char *name)
+{
+    ast_instantiate(ast_goto, ctx, ast_goto_delete);
+    ast_expression_init((ast_expression*)self, (ast_expression_codegen*)&ast_goto_codegen);
+
+    self->name    = util_strdup(name);
+    self->target  = NULL;
+    self->irblock_from = NULL;
+
+    return self;
+}
+
+void ast_goto_delete(ast_goto *self)
 {
     mem_d((void*)self->name);
     ast_expression_delete((ast_expression*)self);
@@ -2655,6 +2681,9 @@ bool ast_switch_codegen(ast_switch *self, ast_function *func, bool lvalue, ir_va
 
 bool ast_label_codegen(ast_label *self, ast_function *func, bool lvalue, ir_value **out)
 {
+    size_t i;
+    ir_value *dummy;
+
     *out = NULL;
     if (lvalue) {
         asterror(ast_ctx(self), "internal error: ast_label cannot be an lvalue");
@@ -2674,6 +2703,51 @@ bool ast_label_codegen(ast_label *self, ast_function *func, bool lvalue, ir_valu
 
     /* enter the new block */
     func->curblock = self->irblock;
+
+    /* Generate all the leftover gotos */
+    for (i = 0; i < vec_size(self->gotos); ++i) {
+        if (!ast_goto_codegen(self->gotos[i], func, false, &dummy))
+            return false;
+    }
+
+    return true;
+}
+
+bool ast_goto_codegen(ast_goto *self, ast_function *func, bool lvalue, ir_value **out)
+{
+    *out = NULL;
+    if (lvalue) {
+        asterror(ast_ctx(self), "internal error: ast_goto cannot be an lvalue");
+        return false;
+    }
+
+    if (self->target->irblock) {
+        if (self->irblock_from) {
+            /* we already tried once, this is the callback */
+            self->irblock_from->final = false;
+            if (!ir_block_create_jump(self->irblock_from, self->target->irblock)) {
+                asterror(ast_ctx(self), "failed to generate goto to `%s`", self->name);
+                return false;
+            }
+        }
+        else
+        {
+            if (!ir_block_create_jump(func->curblock, self->target->irblock)) {
+                asterror(ast_ctx(self), "failed to generate goto to `%s`", self->name);
+                return false;
+            }
+        }
+    }
+    else
+    {
+        /* the target has not yet been created...
+         * close this block in a sneaky way:
+         */
+        func->curblock->final = true;
+        self->irblock_from = func->curblock;
+        ast_label_register_goto(self->target, self);
+    }
+
     return true;
 }
 
diff --git a/ast.h b/ast.h
index 62287fe..3a133ac 100644
--- a/ast.h
+++ b/ast.h
@@ -49,6 +49,7 @@ typedef struct ast_array_index_s ast_array_index;
 typedef struct ast_breakcont_s   ast_breakcont;
 typedef struct ast_switch_s      ast_switch;
 typedef struct ast_label_s       ast_label;
+typedef struct ast_goto_s        ast_goto;
 
 enum {
     TYPE_ast_node,
@@ -70,7 +71,8 @@ enum {
     TYPE_ast_array_index,
     TYPE_ast_breakcont,
     TYPE_ast_switch,
-    TYPE_ast_label
+    TYPE_ast_label,
+    TYPE_ast_goto
 };
 
 #define ast_istype(x, t) ( ((ast_node_common*)x)->nodetype == (TYPE_##t) )
@@ -500,13 +502,33 @@ struct ast_label_s
     ast_expression_common expression;
     const char *name;
     ir_block   *irblock;
+    ast_goto  **gotos;
 };
 
 ast_label* ast_label_new(lex_ctx ctx, const char *name);
 void ast_label_delete(ast_label*);
+void ast_label_register_goto(ast_label*, ast_goto*);
 
 bool ast_label_codegen(ast_label*, ast_function*, bool lvalue, ir_value**);
 
+/* GOTO nodes
+ *
+ * Go to a label, the label node is filled in at a later point!
+ */
+struct ast_goto_s
+{
+    ast_expression_common expression;
+    const char *name;
+    ast_label  *target;
+    ir_block   *irblock_from;
+};
+
+ast_goto* ast_goto_new(lex_ctx ctx, const char *name);
+void ast_goto_delete(ast_goto*);
+void ast_goto_setlabel(ast_goto*, ast_label*);
+
+bool ast_goto_codegen(ast_goto*, ast_function*, bool lvalue, ir_value**);
+
 /* CALL node
  *
  * Contains an ast_expression as target, rather than an ast_function/value.
-- 
2.39.2