| Message ID | 20180820113726.GA88902@kam.mff.cuni.cz |
|---|---|
| State | New |
| Headers | show |
| Series | Do not stream types in DECL_CONTEXT | expand |
On Mon, 20 Aug 2018, Jan Hubicka wrote: > Hi, > this patch drops types from decl context in free lang data. This is not possible > for field decls (because they are chained by TREE_CHAIN), for variably modified > types (becuase it is used in tree_is_indexable and other places) and for > virtual functions/tables (because it is used by devirt machinery to loop back > the type). > > lto Bootstrapped/regtested x86_64-linux, OK? OK. Richard. > * tree.c (free_lang_data_in_decl): Remove types from DECL_CONTEXT > when possible. > Index: tree.c > =================================================================== > --- tree.c (revision 263586) > +++ tree.c (working copy) > @@ -5380,6 +5380,29 @@ free_lang_data_in_decl (tree decl) > nextp = &TREE_CHAIN (var); > } > } > + /* We need to keep field decls associated with their trees. Otherwise tree > + merging may merge some fileds and keep others disjoint wich in turn will > + not do well with TREE_CHAIN pointers linking them. > + > + Also do not drop containing types for virtual methods and tables because > + these are needed by devirtualization. */ > + if (TREE_CODE (decl) != FIELD_DECL > + && ((TREE_CODE (decl) != VAR_DECL && TREE_CODE (decl) != FUNCTION_DECL) > + || !DECL_VIRTUAL_P (decl))) > + { > + tree ctx = DECL_CONTEXT (decl); > + /* Variably modified types are needed for tree_is_indexable to decide > + whether the type needs to go to local or global section. > + This code is semi-broken but for now it is easiest to keep contexts > + as expected. */ > + if (ctx && TYPE_P (ctx) > + && !variably_modified_type_p (ctx, NULL_TREE)) > + { > + while (ctx && TYPE_P (ctx)) > + ctx = TYPE_CONTEXT (ctx); > + DECL_CONTEXT (decl) = ctx; > + } > + } > } > > > >
Index: tree.c =================================================================== --- tree.c (revision 263586) +++ tree.c (working copy) @@ -5380,6 +5380,29 @@ free_lang_data_in_decl (tree decl) nextp = &TREE_CHAIN (var); } } + /* We need to keep field decls associated with their trees. Otherwise tree + merging may merge some fileds and keep others disjoint wich in turn will + not do well with TREE_CHAIN pointers linking them. + + Also do not drop containing types for virtual methods and tables because + these are needed by devirtualization. */ + if (TREE_CODE (decl) != FIELD_DECL + && ((TREE_CODE (decl) != VAR_DECL && TREE_CODE (decl) != FUNCTION_DECL) + || !DECL_VIRTUAL_P (decl))) + { + tree ctx = DECL_CONTEXT (decl); + /* Variably modified types are needed for tree_is_indexable to decide + whether the type needs to go to local or global section. + This code is semi-broken but for now it is easiest to keep contexts + as expected. */ + if (ctx && TYPE_P (ctx) + && !variably_modified_type_p (ctx, NULL_TREE)) + { + while (ctx && TYPE_P (ctx)) + ctx = TYPE_CONTEXT (ctx); + DECL_CONTEXT (decl) = ctx; + } + } }