From a27833ed0d796d1fc44396fd944afee1319c0189 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Thu, 4 Nov 2021 09:31:40 +0200
Subject: [PATCH] all: support `volatile field Type` in struct declarations

---
 vlib/v/ast/ast.v                           | 1 +
 vlib/v/fmt/struct.v                        | 3 ++-
 vlib/v/gen/c/cgen.v                        | 3 ++-
 vlib/v/gen/c/testdata/volatile.c.must_have | 2 ++
 vlib/v/gen/c/testdata/volatile.out         | 4 ++++
 vlib/v/gen/c/testdata/volatile.vv          | 6 ++++++
 vlib/v/parser/struct.v                     | 7 +++++++
 7 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 0e4dd49dea..33f2a05953 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -267,6 +267,7 @@ pub:
 	default_val      string
 	is_mut           bool
 	is_global        bool
+	is_volatile      bool
 pub mut:
 	default_expr     Expr
 	default_expr_typ Type
diff --git a/vlib/v/fmt/struct.v b/vlib/v/fmt/struct.v
index 46af440a5d..ca779489a9 100644
--- a/vlib/v/fmt/struct.v
+++ b/vlib/v/fmt/struct.v
@@ -108,7 +108,8 @@ pub fn (mut f Fmt) struct_decl(node ast.StructDecl) {
 		after_type_comments := field.comments[(before_comments.len + between_comments.len)..]
 		// Handle comments before the field
 		f.comments_before_field(before_comments)
-		f.write('\t$field.name ')
+		volatile_prefix := if field.is_volatile { 'volatile ' } else { '' }
+		f.write('\t$volatile_prefix$field.name ')
 		// Handle comments between field name and type
 		before_len := f.line_len
 		f.comments(between_comments, iembed: true, has_nl: false)
diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index 45fe12130e..e5a693d46b 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -6343,7 +6343,8 @@ fn (mut g Gen) write_types(types []ast.TypeSymbol) {
 						}
 						type_name := g.typ(field.typ)
 						field_name := c_name(field.name)
-						g.type_definitions.writeln('\t$type_name $field_name;')
+						volatile_prefix := if field.is_volatile { 'volatile ' } else { '' }
+						g.type_definitions.writeln('\t$volatile_prefix$type_name $field_name;')
 					}
 				} else {
 					g.type_definitions.writeln('\tEMPTY_STRUCT_DECLARATION;')
diff --git a/vlib/v/gen/c/testdata/volatile.c.must_have b/vlib/v/gen/c/testdata/volatile.c.must_have
index a88594038a..1a4a8a3dde 100644
--- a/vlib/v/gen/c/testdata/volatile.c.must_have
+++ b/vlib/v/gen/c/testdata/volatile.c.must_have
@@ -1,2 +1,4 @@
 volatile int *zzz = HEAP(int, (123));
 volatile int* pzzz = &(*(zzz));
+volatile int a_volatile_field;
+int a_non_volatile_field;
diff --git a/vlib/v/gen/c/testdata/volatile.out b/vlib/v/gen/c/testdata/volatile.out
index f3da5b535e..7cd90623c4 100644
--- a/vlib/v/gen/c/testdata/volatile.out
+++ b/vlib/v/gen/c/testdata/volatile.out
@@ -1,2 +1,6 @@
 123
 &123
+Abc{
+    a_volatile_field: 0
+    a_non_volatile_field: 0
+}
diff --git a/vlib/v/gen/c/testdata/volatile.vv b/vlib/v/gen/c/testdata/volatile.vv
index 2c95812473..1cccc1e4d2 100644
--- a/vlib/v/gen/c/testdata/volatile.vv
+++ b/vlib/v/gen/c/testdata/volatile.vv
@@ -1,4 +1,10 @@
+struct Abc {
+	volatile a_volatile_field     int
+	a_non_volatile_field int
+}
+
 mut volatile zzz := 123
 mut volatile pzzz := &zzz
 println(zzz)
 println(&int(voidptr(pzzz)))
+println(Abc{})
diff --git a/vlib/v/parser/struct.v b/vlib/v/parser/struct.v
index ac3d0cba1b..35a83c611a 100644
--- a/vlib/v/parser/struct.v
+++ b/vlib/v/parser/struct.v
@@ -170,6 +170,11 @@ fn (mut p Parser) struct_decl() ast.StructDecl {
 				}
 			}
 			field_start_pos := p.tok.position()
+			mut is_field_volatile := false
+			if p.tok.kind == .key_volatile {
+				p.next()
+				is_field_volatile = true
+			}
 			is_embed := ((p.tok.lit.len > 1 && p.tok.lit[0].is_capital())
 				|| p.peek_tok.kind == .dot) && language == .v && p.peek_tok.kind != .key_fn
 			is_on_top := ast_fields.len == 0 && !(is_field_mut || is_field_global)
@@ -255,6 +260,7 @@ fn (mut p Parser) struct_decl() ast.StructDecl {
 					is_pub: is_embed || is_field_pub
 					is_mut: is_embed || is_field_mut
 					is_global: is_field_global
+					is_volatile: is_field_volatile
 				}
 			}
 			// save embeds as table fields too, it will be used in generation phase
@@ -270,6 +276,7 @@ fn (mut p Parser) struct_decl() ast.StructDecl {
 				is_pub: is_embed || is_field_pub
 				is_mut: is_embed || is_field_mut
 				is_global: is_field_global
+				is_volatile: is_field_volatile
 			}
 			p.attrs = []
 		}