Add update-alternative for ld

rhbz#1739973

lld.spec

@@ -3,7 +3,7 @@
 
 Name:		lld
 Version:	8.0.0
-Release:	1%{?rc_ver:.rc%{rc_ver}}%{?dist}.1
+Release:	2%{?rc_ver:.rc%{rc_ver}}%{?dist}
 Summary:	The LLVM Linker
 
 License:	NCSA
@@ -27,6 +27,9 @@ BuildRequires:	python3-rpm-macros
 BuildRequires:	python3-lit
 BuildRequires:	llvm-googletest = %{version}
 
+Requires(post): %{_sbindir}/alternatives
+Requires(preun): %{_sbindir}/alternatives
+
 %description
 The LLVM project linker.
 
@@ -76,6 +79,13 @@ cd %{_target_platform}
 chrpath --delete %{buildroot}%{_bindir}/*
 chrpath --delete %{buildroot}%{_libdir}/*.so*
 
+%post
+%{_sbindir}/update-alternatives --install %{_bindir}/ld ld %{_bindir}/ld.lld 1
+
+%postun
+if [ $1 -eq 0 ] ; then
+  %{_sbindir}/update-alternatives --remove ld %{_bindir}/ld.lld
+fi
 
 %check
 
@@ -87,6 +97,7 @@ make -C %{_target_platform} %{?_smp_mflags} check-lld
 %ldconfig_scriptlets libs
 
 %files
+%ghost %{_bindir}/ld
 %{_bindir}/lld*
 %{_bindir}/ld.lld
 %{_bindir}/ld64.lld
@@ -100,6 +111,9 @@ make -C %{_target_platform} %{?_smp_mflags} check-lld
 %{_libdir}/liblld*.so.*
 
 %changelog
+* Tue Aug 13 2019 Tom Stellard <tstellar@redhat.com> - 8.0.0-2
+- Add update-alternative for ld
+
 * Thu Jul 25 2019 Fedora Release Engineering <releng@fedoraproject.org> - 8.0.0-1.1
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_31_Mass_Rebuild
 

tests/ld-alternative/runtest.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# This test assumes lld is already installed.
+
+set -ex
+
+function verify_ld_bfd {
+
+  # Verify that /usr/bin/ld points to ld.bfd.
+  ls -l /etc/alternatives/ld | grep ld.bfd
+
+  # Run ld and verify it invokes ld.bfd
+  /usr/bin/ld --version | grep 'GNU ld'
+}
+
+
+# Verify ld.bfd is still the system linker when lld is installed
+verify_ld_bfd
+
+# Set lld as the system linker
+update-alternatives --set ld /usr/bin/ld.lld
+
+# Verify that /usr/bin/ld points to lld
+ls -l /etc/alternatives/ld | grep ld.lld
+
+# Run ld and verify it invokes lld
+/usr/bin/ld --version | grep 'LLD'
+
+# Uninstall lld and make sure the /usr/bin/ld is reset to ld.bfd
+dnf -y remove lld
+
+verify_ld_bfd

tests/tests-ld-alternative.yml

@@ -0,0 +1,14 @@
+# The ld-alternative test uninstalls lld, so it needs to be run by
+# itself in a separate .yml file so it doesn't modify the test
+# environment for other tests. 
+
+- hosts: localhost
+  roles:
+  - role: standard-test-basic
+    tags:
+      - classic
+    required_packages:
+      - binutils
+      - lld
+    tests:
+      - ld-alternative