Hi David,
on 2021/8/19 上午11:26, David Edelsohn via Gcc-patches wrote:
> Hi, Martin
>
> A few PowerPC-specific testcases started failing yesterday on AIX with
> a strange failure mode: the compiler runs out of memory. As you may
> expect from telling you this in an email reply to your patch, I have
> bisected the failure and landed on your commit. I can alternate
> between the previous commit and your commit, and the failure
> definitely appears with your patch, although I'm unsure how your patch
> affected memory allocation in the compiler. Maybe moving the code
> changed a type of allocation or some memory no longer is being freed?
>
To get rid of GTY variable alloc_object_size_limit looks suspicious,
maybe tree objects returned by alloc_max_size after the change are out
of GC's tracking?
If the suspicion holds, the attached explorative diff may help.
BR,
Kewen
> Previously, compiler bootstrap and all testcases ran with a data size
> of 1GB. After your change, the data size required for those
> particular testcases jumped to 2GB.
>
> The testcases are
>
> gcc/testsuite/gcc.target/powerpc/rlwimi-[012].c
>
> The failure is
>
> cc1: out of memory allocating 65536 bytes after a total of 1608979296
>
> This seems like a significant memory use regression. Any ideas what happened?
>
> Thanks, David
>
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 6653e9e2142..9aefed47be8 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -2717,7 +2717,7 @@ GTFILES = $(CPPLIB_H) $(srcdir)/input.h
$(srcdir)/coretypes.h \
$(srcdir)/sancov.c \
$(srcdir)/ipa-devirt.c \
$(srcdir)/internal-fn.h \
- $(srcdir)/calls.c \
+ $(srcdir)/gimple-ssa-warn-access.cc \
$(srcdir)/omp-general.h \
@all_gtfiles@
diff --git a/gcc/gimple-ssa-warn-access.cc b/gcc/gimple-ssa-warn-access.cc
index f3efe564af0..267ef987edd 100644
--- a/gcc/gimple-ssa-warn-access.cc
+++ b/gcc/gimple-ssa-warn-access.cc
@@ -2301,6 +2301,9 @@ pass_waccess::gate (function *)
|| warn_mismatched_new_delete);
}
+/* The limit set by -Walloc-larger-than=. */
+static GTY(()) tree alloc_object_size_limit;
+
/* Initialize ALLOC_OBJECT_SIZE_LIMIT based on the -Walloc-size-larger-than=
setting if the option is specified, or to the maximum object size if it
is not. Return the initialized value. */
@@ -2308,11 +2311,16 @@ pass_waccess::gate (function *)
static tree
alloc_max_size (void)
{
+ if (alloc_object_size_limit)
+ return alloc_object_size_limit;
+
HOST_WIDE_INT limit = warn_alloc_size_limit;
if (limit == HOST_WIDE_INT_MAX)
limit = tree_to_shwi (TYPE_MAX_VALUE (ptrdiff_type_node));
- return build_int_cst (size_type_node, limit);
+ alloc_object_size_limit = build_int_cst (size_type_node, limit);
+
+ return alloc_object_size_limit;
}
/* Diagnose a call EXP to function FN decorated with attribute alloc_size
@@ -3328,3 +3336,6 @@ make_pass_warn_access (gcc::context *ctxt)
{
return new pass_waccess (ctxt);
}
+
+/* Tell the garbage collector about GTY markers in this source file. */
+#include "gt-gimple-ssa-warn-access.h"
