i386/boot2: -fno-asynchronous-unwind-tables for gcc

The amd64 build of boot2 was failing with gcc 6.3.0 due to being more
than 1 kB too large. It was apparently generating a .eh_frame section
which was not being removed by objcopy -S. The .eh_frame section seems
to be mandatory per the amd64 ABI, but boot2 is compiled for i386 (uses
-m32), and therefore should be optional in this context. Suppress
generation of .eh_frame with the -fno-asynchronous-unwind-tables flag to
gcc. This saves 1348 bytes (the limit is 7680 bytes).

Reviewed by:	dim, imp
Approved by:	markj (mentor)
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D11928
This commit is contained in:
Ryan Libby 2017-08-09 20:13:49 +00:00
parent e54647920b
commit 2473c1b145

View File

@ -38,6 +38,7 @@ CFLAGS= -fomit-frame-pointer \
-Winline
CFLAGS.gcc+= -Os \
-fno-asynchronous-unwind-tables \
--param max-inline-insns-single=100
.if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} <= 40201
CFLAGS.gcc+= -mno-align-long-strings