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Modify trans.rs to allow blocks to result in boxed values

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This commit is contained in:
Brian Anderson 2011-03-31 21:20:10 -04:00
parent bd1c61548e
commit 125bebbf60
1 changed files with 59 additions and 0 deletions
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59
src/comp/middle/trans.rs
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@ -1026,6 +1026,18 @@ fn find_scope_cx(@block_ctxt cx) -> @block_ctxt {
}
}
fn find_outer_scope_cx(@block_ctxt cx) -> @block_ctxt {
auto scope_cx = find_scope_cx(cx);
alt (cx.parent) {
case (parent_some(?b)) {
be find_scope_cx(b);
}
case (parent_none) {
fail;
}
}
}
fn umax(@block_ctxt cx, ValueRef a, ValueRef b) -> ValueRef {
auto cond = cx.build.ICmp(lib.llvm.LLVMIntULT, a, b);
ret cx.build.Select(cond, b, a);
@ -5368,8 +5380,55 @@ fn trans_block(@block_ctxt cx, &ast.block b) -> result {
case (some[@ast.expr](?e)) {
r = trans_expr(bcx, e);
bcx = r.bcx;
if (is_terminated(bcx)) {
ret r;
} else {
// The value resulting from the block gets copied into an
// alloca created in an enclosing scope and it's refcount
// bumped so that it can escape this block. This means that
// it will definitely live until the end of the enclosing
// scope, even if nobody uses it, which may be something of
// a surprise.
auto r_ty = ty.expr_ty(e);
fn is_nil(@ty.t r_ty) -> bool {
alt (r_ty.struct) {
case (ty.ty_nil) {
ret true;
}
case (_) {
ret false;
}
}
}
// FIXME: This is a temporary hack to prevent compile
// failures. There's some expression variant that claims
// to be ty_nil but but does not translate to T_nil. Need
// to hunt it down.
if (!is_nil(r_ty)) {
// This alloca is declared at the function level, above
// the block scope
auto res_alloca = alloc_ty(bcx, r_ty);
bcx = res_alloca.bcx;
auto res_copy = copy_ty(bcx, INIT,
res_alloca.val, r.val, r_ty);
bcx = res_copy.bcx;
fn drop_hoisted_ty(@block_ctxt cx,
ValueRef alloca_val,
@ty.t t) -> result {
auto reg_val = load_scalar_or_boxed(cx,
alloca_val, t);
ret drop_ty(cx, reg_val, t);
}
auto cleanup = bind drop_hoisted_ty(_, res_alloca.val,
r_ty);
find_outer_scope_cx(bcx).cleanups += vec(clean(cleanup));
}
}
}
case (none[@ast.expr]) {