> > On Wed, Nov 25, 2020 at 3:11 PM Jan Hubicka <hubi...@ucw.cz> wrote:
> > >
> > > > On Tue, 24 Nov 2020, Jan Hubicka wrote:
> > > >
> > > > > Hi,
> > > > > at the end of processing function body we loop over basic blocks and
> > > > > free all edges while we do not free the rest. I think this is
> > > > > leftover
> > > > > from time eges was not garbage collected and we was not using
> > > > > ggc_free.
> > > > > It makes more sense to free all associated structures (which is
> > > > > importnat for WPA memory footprint).
> > > > >
> > > > > Bootstrapped/regtested x86_64-linux, OK?
> > > >
> > > > OK.
> > >
> > > Unforutnately the patch does not surive LTO bootstrap. The problem is
> > > that we keep DECL_INITIAL that points to blocks and blocks points to
> > > var_decls and these points to SSA_NAMES that points to statements and
> > > those points to basic blocks.
> >
> > VAR_DECLs point to SSA_NAMEs? It's the other way around. We for sure
> > free SSA_NAMEs (well, maybe not explicitely with ggc_free).
>
> I am going to debug this more carefully now. I think it was VAR_DECL
> with variadic type pointing to SSA_NAME. Should be easy to reduct with
> gcac compiler.
Hi,
it turns out that the pointers to statements leaks through saved scopes
in C++ FE. Scopes seems to point to internal blocks of functions even
after we finish their compiling.
This patch adds code to free pointers. I tried to clear saved_blocks
but it breaks since C++ finalization uses them, but it does not look
into previous class levels.
Patch lto-bootstraps/regtestes x86_64-linux with all languages. OK?
Honza
* cfg.c (free_block): Call ggc_free on BB itself.
* cp-tre.eh (cp_tree_c_finish_parsing): Declare.
* semantics.c (finish_translation_unit): Call finish_parsing
* tree.c (cp_tree_c_finish_parsing): New function.
diff --git a/gcc/cfg.c b/gcc/cfg.c
index 529b6ed2105..e8bd1456c9f 100644
--- a/gcc/cfg.c
+++ b/gcc/cfg.c
@@ -102,8 +102,7 @@ free_block (basic_block bb)
bb->succs = NULL;
vec_free (bb->preds);
bb->preds = NULL;
- /* Do not free BB itself yet since we leak pointers to dead statements
- that points to dead basic blocks. */
+ ggc_free (bb);
}
/* Free the memory associated with the CFG in FN. */
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 021de76e142..665d171d9b0 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -7986,6 +7986,8 @@ struct uid_sensitive_constexpr_evaluation_checker
bool evaluation_restricted_p () const;
};
+void cp_tree_c_finish_parsing ();
+
/* In cp-ubsan.c */
extern void cp_ubsan_maybe_instrument_member_call (tree);
extern void cp_ubsan_instrument_member_accesses (tree *);
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 5ff70ff4844..e9d17c21985 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -3094,6 +3094,7 @@ finish_translation_unit (void)
"%<#pragma omp end declare target%>");
scope_chain->omp_declare_target_attribute = 0;
}
+ cp_tree_c_finish_parsing ();
}
/* Finish a template type parameter, specified as AGGR IDENTIFIER.
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 28e591086b3..e63d383c0a3 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -5844,6 +5844,19 @@ maybe_warn_zero_as_null_pointer_constant (tree expr,
location_t loc)
return false;
}
+/* Release memory we no longer need after parsing. */
+void
+cp_tree_c_finish_parsing ()
+{
+ saved_scope *chain = scope_chain;
+ while (chain)
+ {
+ chain->x_previous_class_level = NULL;
+ chain = chain->prev;
+ }
+ deleted_copy_types = NULL;
+}
+
#if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
/* Complain that some language-specific thing hanging off a tree
node has been accessed improperly. */
