wip: build race detector on amd64

Related: RHEL-33421

Makefile

@@ -0,0 +1,5 @@
+mockbuild:
+	centpkg mockbuild
+
+spectool:
+	spectool -g golang.spec

golang.spec

@@ -97,6 +97,12 @@
 %global version %{go_version}
 %global pkg_release 1
 
+# LLVM source SHA for race detector build
+%global compiler_rt_go_race_sha 51bfeff0e4b0757ff773da6882f4d538996c9b04
+
+# For rpmdev-bumpspec and releng automation.
+%global baserelease 3
+ 
 Name:           golang
 Version:        %{version}
 Release:        1%{?dist}
@@ -114,6 +120,7 @@ Source0:        https://github.com/golang/go/archive/refs/tags/go%{version}.tar.
 Source1:	https://github.com/golang-fips/go/archive/refs/tags/go%{version}-%{pkg_release}-openssl-fips.tar.gz
 # make possible to override default traceback level at build time by setting build tag rpm_crashtraceback
 Source2:        fedora.go
+Source3:        https://github.com/llvm/llvm-project/archive/%{compiler_rt_go_race_sha}.tar.gz
 
 # The compiler is written in Go. Needs go(1.4+) compiler for build.
 # Actual Go based bootstrap compiler provided by above source.
@@ -132,6 +139,10 @@ BuildRequires:  openssl-devel
 # for tests
 BuildRequires:  pcre-devel, glibc-static, perl
 
+# Necessary for building llvm address sanitizer for Go race detector
+BuildRequires: libstdc++-devel
+BuildRequires: clang
+
 Provides:       go = %{version}-%{release}
 Requires:       %{name}-bin = %{version}-%{release}
 Requires:       %{name}-src = %{version}-%{release}
@@ -270,6 +281,7 @@ popd
 sed -i '1s/$/ (%{?rhel:Red Hat} %{version}-%{release})/' VERSION
 
 cp %{SOURCE2} ./src/runtime/
+# If FIPS is enabled, install the FIPS source
 
 %build
 set -xe
@@ -278,6 +290,16 @@ uname -a
 cat /proc/cpuinfo
 cat /proc/meminfo
 
+# Build race detector .syso's from llvm sources
+%global tsan_buildflags %(echo %{build_cflags} | sed 's/-mtls-dialect=gnu2//')
+mkdir ../llvm
+tar -xf %{SOURCE3} -C ../llvm
+tsan_go_dir="../llvm/llvm-project-%{compiler_rt_go_race_sha}/compiler-rt/lib/tsan/go"
+pushd "${tsan_go_dir}"
+  CFLAGS="${tsan_buildflags}" CC=clang GOAMD64=v3 ./buildgo.sh
+popd
+cp "${tsan_go_dir}"/race_linux_amd64.syso ./src/runtime/race/internal/amd64v3/race_linux.syso
+
 # bootstrap compiler GOROOT
 %if !%{golang_bootstrap}
 export GOROOT_BOOTSTRAP=/