alignof, offsetof

1 files changed, 41 insertions, 5 deletions

diff --git a/bootstrap/parse.c b/bootstrap/parse.c
index 0abaf45..31469df 100644
--- a/bootstrap/parse.c
+++ b/bootstrap/parse.c
@@ -907,8 +907,10 @@ structidx2fld(const struct type *ty, int idx) {
 }
 
 static int
-structfldnam2idx(const struct type *ty, const char *name) {
+aggfldnam2idx(const struct type *ty, const char *name) {
    assert(name);
+   if (ty->t != TYunion && ty->t != TYstruct && ty->t != TYeunion)
+      return -1;
    for (int i = 0; i < ty->agg.flds.n; ++i)
       if (!strcmp(name, ty->agg.flds.d[i].name))
          return i;
@@ -917,7 +919,7 @@ structfldnam2idx(const struct type *ty, const char *name) {
 
 static struct aggfield *
 findaggfield(const struct type *ty, const char *name) {
-   int i = structfldnam2idx(ty, name);
+   int i = aggfldnam2idx(ty, name);
    return i < 0 ? NULL : &ty->agg.flds.d[i];
 }
 
@@ -957,7 +959,7 @@ parsestructini(struct parser *P, const struct type *ty) {
       if (lexmatch(P, &tok, '.')) {
          const char *fnam = (tok = lexexpect(P, TKident)).str;
          lexexpect(P, ':');
-         idx = structfldnam2idx(ty, fnam);
+         idx = aggfldnam2idx(ty, fnam);
          if (idx < 0)
             fatal(P, tok.span, "%s %t has no field `%s'", kind, ty, fnam);
       }
@@ -1225,7 +1227,7 @@ pexprimary(struct parser *P) {
       ex.span = tok.span;
    } else if (lexmatch(P, &tok, TKkw_sizeof)) {
       ex.t = Eintlit;
-      ex.ty = ty_isize;
+      ex.ty = ty_usize;
       if (lexmatch(P, &tok, '(')) {
          struct expr exp = parseexpr(P);
          ex.i = exp.ty->size;
@@ -1234,6 +1236,40 @@ pexprimary(struct parser *P) {
          const struct type *ty = parsetype(P);
          ex.i = ty->size;
       }
+   } else if (lexmatch(P, &tok, TKkw_alignof)) {
+      ex.t = Eintlit;
+      ex.ty = ty_usize;
+      if (lexmatch(P, &tok, '(')) {
+         struct expr exp = parseexpr(P);
+         ex.i = exp.ty->align;
+         lexexpect(P, ')');
+      } else {
+         const struct type *ty = parsetype(P);
+         ex.i = ty->align;
+      }
+   } else if (lexmatch(P, &tok, TKkw_offsetof)) {
+      lexexpect(P, '(');
+      const struct type *ty = parsetype(P);
+      lexexpect(P, ',');
+      size_t off = 0;
+      for (;;) {
+         const char *name = (tok = lexexpect(P, TKident)).str;
+         struct aggfield *fld = findaggfield(ty, name);
+         if (!fld) {
+            fatal(P, tok.span, "%t has no such field %T", ty, tok);
+         }
+         off += fld->off;
+         ty = fld->ty;
+         if (!lexmatch(P, &tok, '.')) {
+            lexmatch(P, &tok, ',');
+            lexexpect(P, ')');
+            break;
+         }
+      }
+      ex.t = Eintlit;
+      ex.ty = ty_usize;
+      ex.u = off;
+
    } else {
       experr:
       fatal(P, tok.span, "expected expression (near %s)", tok2str(tok));
@@ -1424,7 +1460,7 @@ pexpostfix(struct parser *P) {
          bool konst = ty->konst;
          ty = unconstify(ty);
          if (ty->t == TYstruct || ty->t == TYunion || ty->t == TYeunion) {
-            int idx = structfldnam2idx(ty, fnam);
+            int idx = aggfldnam2idx(ty, fnam);
             struct aggfield *fld = &ty->agg.flds.d[idx];
             if (idx < 0)
                fatal(P, tok.span, "%t has no such field `%s'", ty, fnam);