rustc: Don't generate landing pad cleanups for boxy things

src/libuv

@@ -1 +1 @@
-Subproject commit 1d6aec9d54c7a684ade521f71a4d538a6a88b14f
+Subproject commit 1170ffba3ac5191930b40c897d4569a9d8a296a3

src/rustc/middle/trans/base.rs

@@ -3640,7 +3640,11 @@ fn raw_block(fcx: fn_ctxt, llbb: BasicBlockRef) -> block {
 // need to make sure those variables go out of scope when the block ends.  We
 // do that by running a 'cleanup' function for each variable.
 // trans_block_cleanups runs all the cleanup functions for the block.
-fn trans_block_cleanups(bcx: block, cleanup_cx: block) ->
+fn trans_block_cleanups(bcx: block, cleanup_cx: block) -> block {
+    trans_block_cleanups_(bcx, cleanup_cx, false)
+}
+
+fn trans_block_cleanups_(bcx: block, cleanup_cx: block, is_lpad: bool) ->
    block {
     let _icx = bcx.insn_ctxt("trans_block_cleanups");
     if bcx.unreachable { ret bcx; }
@@ -3648,7 +3652,15 @@ fn trans_block_cleanups(bcx: block, cleanup_cx: block) ->
     alt check cleanup_cx.kind {
       block_scope({cleanups, _}) {
         vec::riter(copy cleanups) {|cu|
-            alt cu { clean(cfn) | clean_temp(_, cfn) { bcx = cfn(bcx); } }
+            alt cu {
+              clean(cfn, cleanup_type) | clean_temp(_, cfn, cleanup_type) {
+                // Some types don't need to be cleaned up during
+                // landing pads because they can be freed en mass later
+                if cleanup_type == normal_exit_and_unwind || !is_lpad {
+                    bcx = cfn(bcx);
+                }
+              }
+            }
         }
       }
     }
@@ -3662,6 +3674,7 @@ fn cleanup_and_leave(bcx: block, upto: option<BasicBlockRef>,
                      leave: option<BasicBlockRef>) {
     let _icx = bcx.insn_ctxt("cleanup_and_leave");
     let mut cur = bcx, bcx = bcx;
+    let is_lpad = leave == none;
     loop {
         alt cur.kind {
           block_scope(info) if info.cleanups.len() > 0u {
@@ -3674,7 +3687,7 @@ fn cleanup_and_leave(bcx: block, upto: option<BasicBlockRef>,
             let sub_cx = sub_block(bcx, "cleanup");
             Br(bcx, sub_cx.llbb);
             info.cleanup_paths += [{target: leave, dest: sub_cx.llbb}];
-            bcx = trans_block_cleanups(sub_cx, cur);
+            bcx = trans_block_cleanups_(sub_cx, cur, is_lpad);
           }
           _ {}
         }

src/rustc/middle/trans/common.rs

@@ -201,9 +201,14 @@ fn warn_not_to_commit(ccx: @crate_ctxt, msg: str) {
     }
 }
 
+enum cleantype {
+    normal_exit_only,
+    normal_exit_and_unwind
+}
+
 enum cleanup {
-    clean(fn@(block) -> block),
-    clean_temp(ValueRef, fn@(block) -> block),
+    clean(fn@(block) -> block, cleantype),
+    clean_temp(ValueRef, fn@(block) -> block, cleantype),
 }
 
 // Used to remember and reuse existing cleanup paths
@@ -216,15 +221,26 @@ fn scope_clean_changed(info: scope_info) {
     info.landing_pad = none;
 }
 
+fn cleanup_type(cx: ty::ctxt, ty: ty::t) -> cleantype {
+    if ty::type_needs_unwind_cleanup(cx, ty) {
+        normal_exit_and_unwind
+    } else {
+        normal_exit_only
+    }
+}
+
 fn add_clean(cx: block, val: ValueRef, ty: ty::t) {
     if !ty::type_needs_drop(cx.tcx(), ty) { ret; }
+    let cleanup_type = cleanup_type(cx.tcx(), ty);
     in_scope_cx(cx) {|info|
-        info.cleanups += [clean(bind base::drop_ty(_, val, ty))];
+        info.cleanups += [clean(bind base::drop_ty(_, val, ty),
+                                cleanup_type)];
         scope_clean_changed(info);
     }
 }
 fn add_clean_temp(cx: block, val: ValueRef, ty: ty::t) {
     if !ty::type_needs_drop(cx.tcx(), ty) { ret; }
+    let cleanup_type = cleanup_type(cx.tcx(), ty);
     fn do_drop(bcx: block, val: ValueRef, ty: ty::t) ->
        block {
         if ty::type_is_immediate(ty) {
@@ -234,14 +250,17 @@ fn add_clean_temp(cx: block, val: ValueRef, ty: ty::t) {
         }
     }
     in_scope_cx(cx) {|info|
-        info.cleanups += [clean_temp(val, bind do_drop(_, val, ty))];
+        info.cleanups += [clean_temp(val, bind do_drop(_, val, ty),
+                                     cleanup_type)];
         scope_clean_changed(info);
     }
 }
 fn add_clean_temp_mem(cx: block, val: ValueRef, ty: ty::t) {
     if !ty::type_needs_drop(cx.tcx(), ty) { ret; }
+    let cleanup_type = cleanup_type(cx.tcx(), ty);
     in_scope_cx(cx) {|info|
-        info.cleanups += [clean_temp(val, bind base::drop_ty(_, val, ty))];
+        info.cleanups += [clean_temp(val, bind base::drop_ty(_, val, ty),
+                                     cleanup_type)];
         scope_clean_changed(info);
     }
 }
@@ -249,7 +268,8 @@ fn add_clean_free(cx: block, ptr: ValueRef, shared: bool) {
     let free_fn = if shared { bind base::trans_shared_free(_, ptr) }
                   else { bind base::trans_free(_, ptr) };
     in_scope_cx(cx) {|info|
-        info.cleanups += [clean_temp(ptr, free_fn)];
+        info.cleanups += [clean_temp(ptr, free_fn,
+                                     normal_exit_and_unwind)];
         scope_clean_changed(info);
     }
 }
@@ -263,7 +283,7 @@ fn revoke_clean(cx: block, val: ValueRef) {
         let mut i = 0u;
         for cu in info.cleanups {
             alt cu {
-              clean_temp(v, _) if v == val {
+              clean_temp(v, _, _) if v == val {
                 info.cleanups =
                     vec::slice(info.cleanups, 0u, i) +
                     vec::slice(info.cleanups, i + 1u, info.cleanups.len());

src/rustc/middle/ty.rs

@@ -121,6 +121,7 @@ export type_structurally_contains;
 export type_structurally_contains_uniques;
 export type_autoderef;
 export type_param;
+export type_needs_unwind_cleanup;
 export canon_mode;
 export resolved_mode;
 export arg_mode;
@@ -201,6 +202,7 @@ type ctxt =
       rcache: creader_cache,
       short_names_cache: hashmap<t, @str>,
       needs_drop_cache: hashmap<t, bool>,
+      needs_unwind_cleanup_cache: hashmap<t, bool>,
       kind_cache: hashmap<t, kind>,
       ast_ty_to_ty_cache: hashmap<@ast::ty, ast_ty_to_ty_cache_entry>,
       enum_var_cache: hashmap<def_id, @[variant_info]>,
@@ -388,6 +390,7 @@ fn mk_ctxt(s: session::session, dm: resolve::def_map, amap: ast_map::map,
       rcache: mk_rcache(),
       short_names_cache: new_ty_hash(),
       needs_drop_cache: new_ty_hash(),
+      needs_unwind_cleanup_cache: new_ty_hash(),
       kind_cache: new_ty_hash(),
       ast_ty_to_ty_cache: map::hashmap(
           ast_util::hash_ty, ast_util::eq_ty),
@@ -902,6 +905,48 @@ fn type_needs_drop(cx: ctxt, ty: t) -> bool {
     ret result;
 }
 
+// Some things don't need cleanups during unwinding because the
+// task can free them all at once later. Currently only things
+// that only contain scalars and shared boxes can avoid unwind
+// cleanups.
+fn type_needs_unwind_cleanup(cx: ctxt, ty: t) -> bool {
+    alt cx.needs_unwind_cleanup_cache.find(ty) {
+      some(result) { ret result; }
+      none { }
+    }
+
+    // Prevent infinite recursion
+    cx.needs_unwind_cleanup_cache.insert(ty, false);
+
+    let mut needs_unwind_cleanup = false;
+    maybe_walk_ty(ty) {|ty|
+        alt get(ty).struct {
+          ty_nil | ty_bot | ty_bool |
+          ty_int(_) | ty_uint(_) | ty_float(_) |
+          ty_box(_) | ty_rec(_) | ty_tup(_) {
+            true
+          }
+          ty_enum(did, tps) {
+            for v in *enum_variants(cx, did) {
+                for aty in v.args {
+                    let t = substitute_type_params(cx, tps, aty);
+                    needs_unwind_cleanup |= type_needs_unwind_cleanup(cx, t);
+                }
+            }
+            !needs_unwind_cleanup
+          }
+          _ {
+            needs_unwind_cleanup = true;
+            false
+          }
+        }
+    }
+
+    cx.needs_unwind_cleanup_cache.insert(ty, needs_unwind_cleanup);
+
+    ret needs_unwind_cleanup;
+}
+
 enum kind { kind_sendable, kind_copyable, kind_noncopyable, }
 
 // Using these query functons is preferable to direct comparison or matching
@@ -2323,6 +2368,7 @@ fn ast_constr_to_constr<T>(tcx: ctxt, c: @ast::constr_general<T>) ->
     }
 }
 
+
 // Local Variables:
 // mode: rust
 // fill-column: 78;