gcc-7.3: Backport fixes for std::pair high memory usage

C++ applications that contain a specfic use of std::pair with tempates
cause the build to require many gigabytes of RAM to build.

This is a fix that was applied to the upstream GCC 7 branch.

Change-Id: I213f96d1d6332e2dce5765482ff3413f1abd7ff8
(From OE-Core rev: 51a09ba2729a840a9f2f87b68c7f50a3e6ac0d04)

Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Joel Stanley
2018-07-30 14:40:29 +09:30
committed by Richard Purdie
parent b1585dde96
commit 666e078352
2 changed files with 59 additions and 0 deletions

View File

@@ -80,6 +80,7 @@ BACKPORTS = "\
file://0001-Fix-internal-compiler-error-in-testcase.patch \
file://0001-PR-rtl-optimization-83030.patch \
file://0001-Fix-ppc64le-build-Partial-backport-r256656.patch \
file://0001-PR-c-80290-memory-hog-with-std-pair.patch \
"
SRC_URI[md5sum] = "be2da21680f27624f3a87055c4ba5af2"

View File

@@ -0,0 +1,58 @@
From 8c014bceeca6a558519e86b16a8142accc41e94f Mon Sep 17 00:00:00 2001
From: jason <jason@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 28 Jun 2018 00:25:21 +0000
Subject: [PATCH] PR c++/80290 - memory-hog with std::pair.
* pt.c (type_unification_real): Skip non-dependent conversion
check for a nested list argument.
(braced_init_depth): New.
Upstream-Status: Backport
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
gcc/cp/pt.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 79cfd0129226..71077a3b0498 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -19242,6 +19242,24 @@ try_array_deduction (tree tparms, tree targs, tree parm)
/*nondeduced*/false, array_deduction_r);
}
+/* Returns how many levels of { } INIT contains. */
+
+static int
+braced_init_depth (tree init)
+{
+ if (!init || !BRACE_ENCLOSED_INITIALIZER_P (init))
+ return 0;
+ unsigned i; tree val;
+ unsigned max = 0;
+ FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, val)
+ {
+ unsigned elt_d = braced_init_depth (val);
+ if (elt_d > max)
+ max = elt_d;
+ }
+ return max + 1;
+}
+
/* Most parms like fn_type_unification.
If SUBR is 1, we're being called recursively (to unify the
@@ -19478,6 +19496,10 @@ type_unification_real (tree tparms,
if (uses_template_parms (parm))
continue;
+ /* Workaround for c++/80290: avoid combinatorial explosion on
+ deeply nested braced init-lists. */
+ if (braced_init_depth (arg) > 2)
+ continue;
if (check_non_deducible_conversion (parm, arg, strict, flags,
explain_p))
return 1;
--
2.17.1