configure,meson: add option to enable LTO

This patch allows to compile QEMU with link-time optimization (LTO).
Compilation with LTO is handled directly by meson. This patch only
adds the option in configure and forwards the request to meson

Tested with all major versions of clang from 6 to 12

Signed-off-by: Daniele Buono <dbuono@linux.vnet.ibm.com>
Message-Id: <20201204230615.2392-2-dbuono@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/configure b/configure
index 8ef0874ed502dae02888e89266b4ba09ee93da37..b6fb18815155a3c47739c48131e49f59756281b3 100755 (executable)
--- a/configure
+++ b/configure
@@ -242,6 +242,7 @@ host_cc="cc"
 audio_win_int=""
 libs_qga=""
 debug_info="yes"
+lto="false"
 stack_protector=""
 safe_stack=""
 use_containers="yes"
@@ -1182,6 +1183,10 @@ for opt do
   ;;
   --disable-werror) werror="no"
   ;;
+  --enable-lto) lto="true"
+  ;;
+  --disable-lto) lto="false"
+  ;;
   --enable-stack-protector) stack_protector="yes"
   ;;
   --disable-stack-protector) stack_protector="no"
@@ -1779,6 +1784,7 @@ disabled with --disable-FEATURE, default is enabled if available
   module-upgrades try to load modules from alternate paths for upgrades
   debug-tcg       TCG debugging (default is disabled)
   debug-info      debugging information
+  lto             Enable Link-Time Optimization.
   sparse          sparse checker
   safe-stack      SafeStack Stack Smash Protection. Depends on
                   clang/llvm >= 3.7 and requires coroutine backend ucontext.
@@ -6965,6 +6971,7 @@ NINJA=$ninja $meson setup \
         -Db_pie=$(if test "$pie" = yes; then echo true; else echo false; fi) \
         ${staticpic:+-Db_staticpic=$staticpic} \
         -Db_coverage=$(if test "$gcov" = yes; then echo true; else echo false; fi) \
+        -Db_lto=$lto \
         -Dmalloc=$malloc -Dmalloc_trim=$malloc_trim -Dsparse=$sparse \
         -Dkvm=$kvm -Dhax=$hax -Dwhpx=$whpx -Dhvf=$hvf \
         -Dxen=$xen -Dxen_pci_passthrough=$xen_pci_passthrough -Dtcg=$tcg \

diff --git a/meson.build b/meson.build
index 372576f82c5054080e0174851667b8d015876b72..d05d880114d271e84815c826c4946aecee9654e0 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -2080,6 +2080,7 @@ summary_info += {'gprof enabled':     config_host.has_key('CONFIG_GPROF')}
 summary_info += {'sparse enabled':    sparse.found()}
 summary_info += {'strip binaries':    get_option('strip')}
 summary_info += {'profiler':          config_host.has_key('CONFIG_PROFILER')}
+summary_info += {'link-time optimization (LTO)': get_option('b_lto')}
 summary_info += {'static build':      config_host.has_key('CONFIG_STATIC')}
 if targetos == 'darwin'
   summary_info += {'Cocoa support': config_host.has_key('CONFIG_COCOA')}