compact compiler ids and spans to reduce memory usage

compiler/ast/ast.odin

@@ -4,9 +4,63 @@ import "../source"
 import "../symbol"
 import "core:mem"
 
-INVALID_ID :: -1
+Expr_Id :: distinct u32
+Stmt_Id :: distinct u32
+Function_Id :: distinct u32
+Global_Id :: distinct u32
+Import_Id :: distinct u32
+File_Id :: distinct u32
+Package_Id :: distinct u32
 
-Type_Syntax :: enum {
+INVALID_EXPR :: Expr_Id(0xffff_ffff)
+INVALID_STMT :: Stmt_Id(0xffff_ffff)
+INVALID_FUNCTION :: Function_Id(0xffff_ffff)
+INVALID_GLOBAL :: Global_Id(0xffff_ffff)
+INVALID_IMPORT :: Import_Id(0xffff_ffff)
+INVALID_FILE :: File_Id(0xffff_ffff)
+INVALID_PACKAGE :: Package_Id(0xffff_ffff)
+
+expr_id :: proc(index: int) -> Expr_Id {
+	assert(index >= 0 && u64(index) < u64(INVALID_EXPR))
+	return Expr_Id(index)
+}
+
+stmt_id :: proc(index: int) -> Stmt_Id {
+	assert(index >= 0 && u64(index) < u64(INVALID_STMT))
+	return Stmt_Id(index)
+}
+
+function_id :: proc(index: int) -> Function_Id {
+	assert(index >= 0 && u64(index) < u64(INVALID_FUNCTION))
+	return Function_Id(index)
+}
+
+global_id :: proc(index: int) -> Global_Id {
+	assert(index >= 0 && u64(index) < u64(INVALID_GLOBAL))
+	return Global_Id(index)
+}
+
+import_id :: proc(index: int) -> Import_Id {
+	assert(index >= 0 && u64(index) < u64(INVALID_IMPORT))
+	return Import_Id(index)
+}
+
+file_id :: proc(index: int) -> File_Id {
+	assert(index >= 0 && u64(index) < u64(INVALID_FILE))
+	return File_Id(index)
+}
+
+package_id :: proc(index: int) -> Package_Id {
+	assert(index >= 0 && u64(index) < u64(INVALID_PACKAGE))
+	return Package_Id(index)
+}
+
+index :: proc(id: $T, invalid: T, count: int) -> (int, bool) {
+	value := int(id)
+	return value, id != invalid && value < count
+}
+
+Type_Syntax :: enum u8 {
 	Invalid,
 	Int,
 	I8,
@@ -16,7 +70,7 @@ Type_Syntax :: enum {
 	Void,
 }
 
-Expr_Kind :: enum {
+Expr_Kind :: enum u8 {
 	Invalid,
 	Integer,
 	Name,
@@ -25,15 +79,15 @@ Expr_Kind :: enum {
 }
 
 Expr :: struct {
-	kind:       Expr_Kind,
 	span:       source.Span,
+	integer:    i64,
+	args:       []Expr_Id,
 	qualifier:  symbol.Id,
 	name:       symbol.Id,
-	integer:    i64,
-	left:       int,
-	right:      int,
-	args:       []int,
-	diagnostic: int,
+	left:       Expr_Id,
+	right:      Expr_Id,
+	diagnostic: source.Diagnostic_Id,
+	kind:       Expr_Kind,
 }
 
 Param :: struct {
@@ -42,7 +96,7 @@ Param :: struct {
 	type: Type_Syntax,
 }
 
-Stmt_Kind :: enum {
+Stmt_Kind :: enum u8 {
 	Invalid,
 	Declaration,
 	Assignment,
@@ -56,49 +110,49 @@ Stmt :: struct {
 	name:       symbol.Id,
 	type:       Type_Syntax,
 	immutable:  bool,
-	expr:       int,
-	diagnostic: int,
+	expr:       Expr_Id,
+	diagnostic: source.Diagnostic_Id,
 }
 
 Function :: struct {
 	span:       source.Span,
 	name:       symbol.Id,
-	pkg:        int,
-	file:       int,
+	pkg:        Package_Id,
+	file:       File_Id,
 	c_abi:      bool,
 	has_body:   bool,
 	params:     []Param,
 	result:     Type_Syntax,
-	body:       []int,
-	diagnostic: int,
+	body:       []Stmt_Id,
+	diagnostic: source.Diagnostic_Id,
 }
 
 Global :: struct {
 	span:       source.Span,
 	name:       symbol.Id,
-	pkg:        int,
-	file:       int,
+	pkg:        Package_Id,
+	file:       File_Id,
 	type:       Type_Syntax,
 	immutable:  bool,
-	expr:       int,
-	diagnostic: int,
+	expr:       Expr_Id,
+	diagnostic: source.Diagnostic_Id,
 }
 
 Import :: struct {
 	span:       source.Span,
 	alias:      symbol.Id,
 	path:       string,
-	pkg:        int,
-	file:       int,
-	target:     int,
+	pkg:        Package_Id,
+	file:       File_Id,
+	target:     Package_Id,
 	valid:      bool,
 	used:       bool,
-	diagnostic: int,
+	diagnostic: source.Diagnostic_Id,
 }
 
 File :: struct {
-	source:  int,
-	pkg:     int,
+	source:  source.Source_Id,
+	pkg:     Package_Id,
 }
 
 Package :: struct {