git: e1d2967ba630 - main - sys/conf: Support building kasan with gcc on arm64

The branch main has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=e1d2967ba6309bba5a3d73ad637f43d0e33f71ec

commit e1d2967ba6309bba5a3d73ad637f43d0e33f71ec
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2024-09-27 15:23:57 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2024-10-15 17:24:41 +0000

    sys/conf: Support building kasan with gcc on arm64
    
     - Remove -mllvm flags that don't exist in gcc
     - Set the shadow offset with -fasan-shadow-offset
     - Remove this when kasan is disabled as it's an error to use this
       when not building for kasan under gcc
    
    This allows the arm64 GENERIC-KASAN kernel to build with gcc13.
    
    Reviewed by:    brooks
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D45300
---
 sys/conf/kern.pre.mk | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index 50a81a29d18d..d0a66ceceae2 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -95,13 +95,15 @@ COMPAT_FREEBSD32_ENABLED!= grep COMPAT_FREEBSD32 opt_global.h || true ; echo
 KASAN_ENABLED!=	grep KASAN opt_global.h || true ; echo
 .if !empty(KASAN_ENABLED)
 SAN_CFLAGS+=	-DSAN_NEEDS_INTERCEPTORS -DSAN_INTERCEPTOR_PREFIX=kasan \
-		-fsanitize=kernel-address \
-		-mllvm -asan-stack=true \
+		-fsanitize=kernel-address
+.if ${COMPILER_TYPE} == "clang"
+SAN_CFLAGS+=	-mllvm -asan-stack=true \
 		-mllvm -asan-instrument-dynamic-allocas=true \
 		-mllvm -asan-globals=true \
 		-mllvm -asan-use-after-scope=true \
 		-mllvm -asan-instrumentation-with-call-threshold=0 \
 		-mllvm -asan-instrument-byval=false
+.endif
 
 .if ${MACHINE_CPUARCH} == "aarch64"
 # KASAN/ARM64 TODO: -asan-mapping-offset is calculated from:
@@ -111,7 +113,11 @@ SAN_CFLAGS+=	-DSAN_NEEDS_INTERCEPTORS -DSAN_INTERCEPTOR_PREFIX=kasan \
 #	KASAN_MIN_ADDRESS, and this offset value should eventually be
 #	upstreamed similar to: https://reviews.llvm.org/D98285
 #
+.if ${COMPILER_TYPE} == "clang"
 SAN_CFLAGS+=	-mllvm -asan-mapping-offset=0xdfff208000000000
+.else
+SAN_CFLAGS+=	-fasan-shadow-offset=0xdfff208000000000
+.endif
 .elif ${MACHINE_CPUARCH} == "amd64" && \
       ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 180000
 # Work around https://github.com/llvm/llvm-project/issues/87923, which leads to