From 7827280d96c975aff2b43dfb7b37d6e3c5ab7ad3 Mon Sep 17 00:00:00 2001
From: Leo Tenenbaum <pommicket@gmail.com>
Date: Wed, 15 Jul 2020 00:28:42 -0400
Subject: fix struct definition generation order

---
 cgen.c   | 72 +++++++++++++++++++++++++++++++++++++++++++++++++---------------
 main.c   |  1 -
 test.toc | 15 +++++++-------
 types.h  |  7 ++++---
 4 files changed, 67 insertions(+), 28 deletions(-)

diff --git a/cgen.c b/cgen.c
index 6c03065..2ff424c 100644
--- a/cgen.c
+++ b/cgen.c
@@ -1974,6 +1974,61 @@ static void cgen_global_decl(CGenerator *g, Declaration *d) {
 	}
 }
 
+// this complicated stuff is necessary so that the order of the struct definitions is correct.
+// for example, if we have
+// a ::= struct { x: [5]b; }
+// b ::= struct { foo: int; }
+// we need b to be generated before a
+
+static void cgen_struct_def(CGenerator *g, StructDef *sdef);
+
+static void cgen_struct_defs_needed_by_type(CGenerator *g, Type *t) {
+	switch (t->kind) {
+	case TYPE_STRUCT:
+		cgen_struct_def(g, t->struc);
+		break;
+	case TYPE_ARR:
+		cgen_struct_defs_needed_by_type(g, t->arr->of);
+		break;
+	case TYPE_FN:
+	case TYPE_SLICE:
+	case TYPE_PTR:
+	case TYPE_BUILTIN:
+		break;
+	case TYPE_TUPLE:
+	case TYPE_UNKNOWN:
+	case TYPE_EXPR:
+		assert(0);
+		break;
+	}
+}
+
+static void cgen_struct_def(CGenerator *g, StructDef *sdef) {
+	assert(sdef->flags & STRUCT_DEF_RESOLVED);
+	if (sdef->flags & STRUCT_DEF_CGENERATED) {
+		return;
+	}
+	sdef->flags |= STRUCT_DEF_CGENERATED;
+	arr_foreach(sdef->fields, Field, field)
+		cgen_struct_defs_needed_by_type(g, field->type);
+	cgen_write(g, "struct ");
+	cgen_struct_name(g, sdef);
+	cgen_write(g, "{");
+	cgen_nl(g);
+	++g->indent_lvl;
+	arr_foreach(sdef->fields, Field, field) {
+		cgen_type_pre(g, field->type);
+		cgen_write(g, " ");
+		cgen_ident_simple(g, field->name);
+		cgen_type_post(g, field->type);
+		cgen_write(g, ";");
+		cgen_nl(g);
+	}
+	--g->indent_lvl;
+	cgen_write(g, "};");
+	cgen_nl(g);
+}
+
 static void cgen_file(CGenerator *g, ParsedFile *f, Typer *tr) {
 	g->block = NULL;
 	g->nms = NULL;
@@ -2032,22 +2087,7 @@ static void cgen_file(CGenerator *g, ParsedFile *f, Typer *tr) {
 	// struct definitions
 	arr_foreach(tr->all_structs, StructDefPtr, sdefp) {
 		StructDef *sdef = *sdefp;
-		cgen_write(g, "struct ");
-		cgen_struct_name(g, sdef);
-		cgen_write(g, "{");
-		cgen_nl(g);
-		++g->indent_lvl;
-		arr_foreach(sdef->fields, Field, field) {
-			cgen_type_pre(g, field->type);
-			cgen_write(g, " ");
-			cgen_ident_simple(g, field->name);
-			cgen_type_post(g, field->type);
-			cgen_write(g, ";");
-			cgen_nl(g);
-		}
-		--g->indent_lvl;
-		cgen_write(g, "};");
-		cgen_nl(g);
+		cgen_struct_def(g, sdef);
 	}
 	
 	cgen_write(g, "/* declarations */\n");
diff --git a/main.c b/main.c
index 0a75e61..7455951 100644
--- a/main.c
+++ b/main.c
@@ -8,7 +8,6 @@
 see development.md for development information
 
 @TODO:
-see todo in test.toc
 see note in types.c : we probably shouldn't go to the trouble of evaluating this (just do this stuff if it's an ident)
 ensure that in s[a:b] s is an l-value if it's an array
 make sure you can't pass a function template or a tuple to varargs
diff --git a/test.toc b/test.toc
index 37f63f7..ade7c93 100644
--- a/test.toc
+++ b/test.toc
@@ -122,14 +122,6 @@ some_fn ::= fn(a,b,c: int, d,e,f := 3.0) y : f64 = 3.111 {
 }
 
 main ::= fn() {
-	// @TODO: moving this to the bottom of main screws up the order the structs are generated in.
-	Point2D ::= struct {
-		x, y : int;
-	}
-	Point ::= struct {
-		use p: Point2D;
-		z: float;
-	}
 	foo0 := int == int;
 	bar0 := int == float;
 	foo1 := &&&int == &&&u8;
@@ -162,5 +154,12 @@ main ::= fn() {
 	xx ::= fn() (int, int) {
 		return 3, 5;
 	}
+	Point2D ::= struct {
+		x, y : int;
+	}
+	Point ::= struct {
+		use p: Point2D;
+		z: float;
+	}
 }
 main();
diff --git a/types.h b/types.h
index bca892d..99648ad 100644
--- a/types.h
+++ b/types.h
@@ -513,9 +513,10 @@ typedef Block *BlockPtr;
 
 enum {
 	STRUCT_DEF_FOUND_OFFSETS = 0x01,
-	STRUCT_DEF_RESOLVED = 0x10,
-	STRUCT_DEF_RESOLVING = 0x20,
-	STRUCT_DEF_RESOLVING_FAILED = 0x40
+	STRUCT_DEF_CGENERATED = 0x02,
+	STRUCT_DEF_RESOLVED = 0x04,
+	STRUCT_DEF_RESOLVING = 0x08,
+	STRUCT_DEF_RESOLVING_FAILED = 0x10
 };
 typedef U8 StructFlags;
 typedef struct StructDef {
-- 
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