Bug 1413570 - Disable SSE2 when building mozjemalloc on x86 during PGO profile gen phase. r?froydnj Because of alignment issues due to the system glibc when running the SSE2 gcov code generated during the PGO profile gen phase, Firefox crashes when running the PGO profile. We work around the issue by disabling SSE2 when building mozjemalloc during that phase. That shouldn't affect the coverage data anyways, which is bound to the original C++ code, and the profile-use code generation will still emit SSE2 based on the coverage data if it needs to.

new file mode 100644
--- /dev/null
+++ b/memory/build/Makefile.in
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Workaround for alignment problems in gcov code. See
+# https://bugzilla.mozilla.org/show_bug.cgi?id=1413570#c2.
+ifeq ($(CPU_ARCH),x86)
+PROFILE_GEN_CFLAGS += -mno-sse2
+endif