From b35d148a8d8f7d9237173c70f18cd42d20f299ff Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@cs.stanford.edu>
Date: Fri, 25 Sep 2020 14:48:38 +0900
Subject: [PATCH] Add __attribute__((aligned(N)) for struct declaration

---
 parse.c          | 45 ++++++++++++++++++++++++++++++++-------------
 test/attribute.c | 18 ++++++++++++++++++
 2 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/parse.c b/parse.c
index 825e91a..6acaeb8 100644
--- a/parse.c
+++ b/parse.c
@@ -2595,25 +2595,44 @@ static void struct_members(Token **rest, Token *tok, Type *ty) {
   ty->members = head.next;
 }
 
-// attribute = ("__attribute__" "(" "(" "packed" ")" ")")?
-static Token *attribute(Token *tok, Type *ty) {
-  if (!equal(tok, "__attribute__"))
-    return tok;
+// attribute = ("__attribute__" "(" "(" "packed" ")" ")")*
+static Token *attribute_list(Token *tok, Type *ty) {
+  while (consume(&tok, tok, "__attribute__")) {
+    tok = skip(tok, "(");
+    tok = skip(tok, "(");
+
+    bool first = true;
+
+    while (!consume(&tok, tok, ")")) {
+      if (!first)
+        tok = skip(tok, ",");
+      first = false;
+
+      if (consume(&tok, tok, "packed")) {
+        ty->is_packed = true;
+        continue;
+      }
+
+      if (consume(&tok, tok, "aligned")) {
+        tok = skip(tok, "(");
+        ty->align = const_expr(&tok, tok);
+        tok = skip(tok, ")");
+        continue;
+      }
+
+      error_tok(tok, "unknown attribute");
+    }
+
+    tok = skip(tok, ")");
+  }
 
-  tok = tok->next;
-  tok = skip(tok, "(");
-  tok = skip(tok, "(");
-  tok = skip(tok, "packed");
-  tok = skip(tok, ")");
-  tok = skip(tok, ")");
-  ty->is_packed = true;
   return tok;
 }
 
 // struct-union-decl = attribute? ident? ("{" struct-members)?
 static Type *struct_union_decl(Token **rest, Token *tok) {
   Type *ty = struct_type();
-  tok = attribute(tok, ty);
+  tok = attribute_list(tok, ty);
 
   // Read a tag.
   Token *tag = NULL;
@@ -2638,7 +2657,7 @@ static Type *struct_union_decl(Token **rest, Token *tok) {
 
   // Construct a struct object.
   struct_members(&tok, tok, ty);
-  *rest = attribute(tok, ty);
+  *rest = attribute_list(tok, ty);
 
   if (tag) {
     // If this is a redefinition, overwrite a previous type.
diff --git a/test/attribute.c b/test/attribute.c
index a9adf39..9195d3b 100644
--- a/test/attribute.c
+++ b/test/attribute.c
@@ -16,6 +16,24 @@ int main() {
   ASSERT(1, offsetof(struct __attribute__((packed)) T { char a; int b[2]; }, b));
   ASSERT(1, _Alignof(struct __attribute__((packed)) { char a; int b[2]; }));
 
+  ASSERT(8, ({ struct __attribute__((aligned(8))) { int a; } x; _Alignof(x); }));
+  ASSERT(8, ({ struct { int a; } __attribute__((aligned(8))) x; _Alignof(x); }));
+
+  ASSERT(8, ({ struct __attribute__((aligned(8), packed)) { char a; int b; } x; _Alignof(x); }));
+  ASSERT(8, ({ struct { char a; int b; } __attribute__((aligned(8), packed)) x; _Alignof(x); }));
+  ASSERT(1, offsetof(struct __attribute__((aligned(8), packed)) { char a; int b; }, b));
+  ASSERT(1, offsetof(struct { char a; int b; } __attribute__((aligned(8), packed)), b));
+
+  ASSERT(8, ({ struct __attribute__((aligned(8))) __attribute__((packed)) { char a; int b; } x; _Alignof(x); }));
+  ASSERT(8, ({ struct { char a; int b; } __attribute__((aligned(8))) __attribute__((packed)) x; _Alignof(x); }));
+  ASSERT(1, offsetof(struct __attribute__((aligned(8))) __attribute__((packed)) { char a; int b; }, b));
+  ASSERT(1, offsetof(struct { char a; int b; } __attribute__((aligned(8))) __attribute__((packed)), b));
+
+  ASSERT(8, ({ struct __attribute__((aligned(8))) { char a; int b; } __attribute__((packed)) x; _Alignof(x); }));
+  ASSERT(1, offsetof(struct __attribute__((aligned(8))) { char a; int b; } __attribute__((packed)), b));
+
+  ASSERT(16, ({ struct __attribute__((aligned(8+8))) { char a; int b; } x; _Alignof(x); }));
+
   printf("OK\n");
   return 0;
 }