automake: ask the linker to do garbage collection

By doing GC the linker removes all the symbols that are not referenced
and/or used by the final library. This results in a saving of ~100K
up-to ~600K per (stripped) binary (classic vs gallium drivers).

If interested one can ask the compiler to print the sections that are
removed using -Wl,--print-gc-sections.

v2: Check if ld supports the flag before using it.

Signed-off-by: Emil Velikov <[email protected]>
Acked-by: Matt Turner <[email protected]> (v1)

20 files changed, 38 insertions, 0 deletions

diff --git a/configure.ac b/configure.ac
index 3055de67a7e..af1b0d1fa40 100644
--- a/configure.ac
+++ b/configure.ac
@@ -316,6 +316,22 @@ if test "x$enable_debug" = xyes; then
 fi
 
 dnl
+dnl Check if linker supports garbage collection
+dnl
+save_LDFLAGS=$LDFLAGS
+LDFLAGS="$LDFLAGS -Wl,--gc-sections"
+AC_MSG_CHECKING([whether ld supports --gc-sections])
+AC_LINK_IFELSE(
+    [AC_LANG_SOURCE([static char UnusedFunc() { return 5; } int main() { return 0;}])],
+    [AC_MSG_RESULT([yes])
+        GC_SECTIONS="-Wl,--gc-sections";],
+    [AC_MSG_RESULT([no])
+        GC_SECTIONS="";])
+LDFLAGS=$save_LDFLAGS
+
+AC_SUBST([GC_SECTIONS])
+
+dnl
 dnl compatibility symlinks
 dnl
 case "$host_os" in
diff --git a/src/egl/main/Makefile.am b/src/egl/main/Makefile.am
index 57c9ccd6abb..e4c2539f73c 100644
--- a/src/egl/main/Makefile.am
+++ b/src/egl/main/Makefile.am
@@ -77,6 +77,7 @@ libEGL_la_LDFLAGS = \
 	-no-undefined \
 	-version-number 1:0 \
 	-Wl,-Bsymbolic \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 if HAVE_EGL_PLATFORM_X11
diff --git a/src/egl/wayland/wayland-egl/Makefile.am b/src/egl/wayland/wayland-egl/Makefile.am
index 3c2673a6486..d3fe11769ec 100644
--- a/src/egl/wayland/wayland-egl/Makefile.am
+++ b/src/egl/wayland/wayland-egl/Makefile.am
@@ -11,6 +11,7 @@ libwayland_egl_la_SOURCES = wayland-egl.c
 libwayland_egl_la_LDFLAGS = \
 	-no-undefined \
 	-version-info 1 \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 TESTS = wayland-egl-symbols-check
diff --git a/src/gallium/Automake.inc b/src/gallium/Automake.inc
index 1151f916bef..56f1433a0f8 100644
--- a/src/gallium/Automake.inc
+++ b/src/gallium/Automake.inc
@@ -57,6 +57,7 @@ GALLIUM_DRI_LINKER_FLAGS = \
 	-shared \
 	-module \
 	-avoid-version \
+	$(GC_SECTIONS) \
 	-Wl,--version-script=$(DRI_VERSION_SCRIPT)
 
 GALLIUM_VDPAU_LINKER_FLAGS = \
@@ -65,6 +66,7 @@ GALLIUM_VDPAU_LINKER_FLAGS = \
 	-no-undefined \
 	-version-number $(VDPAU_MAJOR):$(VDPAU_MINOR) \
 	-export-symbols-regex $(VDPAU_EXPORTS) \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 GALLIUM_XVMC_LINKER_FLAGS = \
@@ -73,6 +75,7 @@ GALLIUM_XVMC_LINKER_FLAGS = \
 	-no-undefined \
 	-version-number $(XVMC_MAJOR):$(XVMC_MINOR) \
 	-export-symbols-regex '^XvMC' \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 GALLIUM_OMX_LINKER_FLAGS = \
@@ -80,6 +83,7 @@ GALLIUM_OMX_LINKER_FLAGS = \
 	-module \
 	-no-undefined \
 	-export-symbols-regex $(EXPORTS) \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 GALLIUM_VDPAU_LIB_DEPS = \
diff --git a/src/gallium/targets/egl-static/Makefile.am b/src/gallium/targets/egl-static/Makefile.am
index 55eb3baaa06..58ecf697ce9 100644
--- a/src/gallium/targets/egl-static/Makefile.am
+++ b/src/gallium/targets/egl-static/Makefile.am
@@ -48,6 +48,7 @@ AM_LDFLAGS = \
 	-module \
 	-no-undefined \
 	-avoid-version \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined \
 	-Wl,--version-script=$(top_srcdir)/src/gallium/targets/egl-static/egl.link
 
diff --git a/src/gallium/targets/gbm/Makefile.am b/src/gallium/targets/gbm/Makefile.am
index c109ddbb463..22b4826391e 100644
--- a/src/gallium/targets/gbm/Makefile.am
+++ b/src/gallium/targets/gbm/Makefile.am
@@ -70,6 +70,7 @@ gbm_gallium_drm_la_LDFLAGS = \
 	-module \
 	-no-undefined \
 	-avoid-version \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 if HAVE_MESA_LLVM
diff --git a/src/gallium/targets/libgl-xlib/Makefile.am b/src/gallium/targets/libgl-xlib/Makefile.am
index d7aec7b5b50..ef3d23ebcd9 100644
--- a/src/gallium/targets/libgl-xlib/Makefile.am
+++ b/src/gallium/targets/libgl-xlib/Makefile.am
@@ -47,6 +47,7 @@ libGL_la_SOURCES = xlib.c
 libGL_la_LDFLAGS = \
 	-no-undefined \
 	-version-number $(GL_MAJOR):$(GL_MINOR):$(GL_TINY) \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 libGL_la_LIBADD = \
diff --git a/src/gallium/targets/opencl/Makefile.am b/src/gallium/targets/opencl/Makefile.am
index b401d10d7a7..aae31ff3366 100644
--- a/src/gallium/targets/opencl/Makefile.am
+++ b/src/gallium/targets/opencl/Makefile.am
@@ -6,6 +6,7 @@ lib@OPENCL_LIBNAME@_la_LDFLAGS = \
 	$(LLVM_LDFLAGS) \
 	-no-undefined \
 	-version-number 1:0 \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 
diff --git a/src/gallium/targets/osmesa/Makefile.am b/src/gallium/targets/osmesa/Makefile.am
index 651fc5d2b45..559135cc5fe 100644
--- a/src/gallium/targets/osmesa/Makefile.am
+++ b/src/gallium/targets/osmesa/Makefile.am
@@ -43,6 +43,7 @@ lib@OSMESA_LIB@_la_LDFLAGS = \
 	-module \
 	-no-undefined \
 	-version-number @OSMESA_VERSION@ \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 
diff --git a/src/gallium/targets/pipe-loader/Makefile.am b/src/gallium/targets/pipe-loader/Makefile.am
index 00823fe5bdd..fa463addcc5 100644
--- a/src/gallium/targets/pipe-loader/Makefile.am
+++ b/src/gallium/targets/pipe-loader/Makefile.am
@@ -49,6 +49,7 @@ AM_LDFLAGS = \
 	-module \
 	-no-undefined \
 	-avoid-version \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined \
 	-Wl,--version-script=$(top_srcdir)/src/gallium/targets/pipe-loader/pipe.link
 
diff --git a/src/gallium/targets/xa/Makefile.am b/src/gallium/targets/xa/Makefile.am
index 214c51df883..21f29cfa65e 100644
--- a/src/gallium/targets/xa/Makefile.am
+++ b/src/gallium/targets/xa/Makefile.am
@@ -67,6 +67,7 @@ endif
 libxatracker_la_LDFLAGS = \
 	-no-undefined \
 	-version-number $(XA_MAJOR):$(XA_MINOR):$(XA_TINY) \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 if HAVE_MESA_LLVM
diff --git a/src/gbm/Makefile.am b/src/gbm/Makefile.am
index c71a974015b..ea06ce1607d 100644
--- a/src/gbm/Makefile.am
+++ b/src/gbm/Makefile.am
@@ -22,6 +22,7 @@ libgbm_la_SOURCES = \
 libgbm_la_LDFLAGS = \
 	-no-undefined \
 	-version-info 1:0 \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 libgbm_la_LIBADD = \
diff --git a/src/glx/Makefile.am b/src/glx/Makefile.am
index 0c99c0709d6..aa7666aa93c 100644
--- a/src/glx/Makefile.am
+++ b/src/glx/Makefile.am
@@ -112,6 +112,7 @@ GL_LDFLAGS = \
 	-no-undefined \
 	-version-number 1:2 \
 	-Wl,-Bsymbolic \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 lib@GL_LIB@_la_SOURCES =
diff --git a/src/mapi/es1api/Makefile.am b/src/mapi/es1api/Makefile.am
index b9581184a96..febb137eafa 100644
--- a/src/mapi/es1api/Makefile.am
+++ b/src/mapi/es1api/Makefile.am
@@ -47,6 +47,7 @@ libGLESv1_CM_la_LIBADD = $(GLESv1_CM_LIB_DEPS)
 libGLESv1_CM_la_LDFLAGS = \
 	-no-undefined \
 	-version-number 1:1 \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 if HAVE_SHARED_GLAPI
diff --git a/src/mapi/es2api/Makefile.am b/src/mapi/es2api/Makefile.am
index 1fb6d7c9604..e694a36e5d3 100644
--- a/src/mapi/es2api/Makefile.am
+++ b/src/mapi/es2api/Makefile.am
@@ -51,6 +51,7 @@ libGLESv2_la_LIBADD = $(GLESv2_LIB_DEPS)
 libGLESv2_la_LDFLAGS = \
 	-no-undefined \
 	-version-number 2 \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 if HAVE_SHARED_GLAPI
diff --git a/src/mapi/shared-glapi/Makefile.am b/src/mapi/shared-glapi/Makefile.am
index 7e1068fdfec..33a939a90f9 100644
--- a/src/mapi/shared-glapi/Makefile.am
+++ b/src/mapi/shared-glapi/Makefile.am
@@ -11,6 +11,7 @@ libglapi_la_SOURCES = $(MAPI_GLAPI_FILES)
 libglapi_la_LIBADD = $(PTHREAD_LIBS) $(SELINUX_LIBS)
 libglapi_la_LDFLAGS = \
 	-no-undefined \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 include $(GLAPI)/gen/glapi_gen.mk
diff --git a/src/mapi/vgapi/Makefile.am b/src/mapi/vgapi/Makefile.am
index f85addc7c31..f946b9bb6f9 100644
--- a/src/mapi/vgapi/Makefile.am
+++ b/src/mapi/vgapi/Makefile.am
@@ -47,6 +47,7 @@ libOpenVG_la_LIBADD = $(VG_LIB_DEPS)
 libOpenVG_la_LDFLAGS = \
 	-no-undefined \
 	-version-number 1 \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 vgapi_tmp.h: $(srcdir)/vgapi.csv $(top_srcdir)/src/mapi/mapi_abi.py
diff --git a/src/mesa/drivers/dri/Makefile.am b/src/mesa/drivers/dri/Makefile.am
index 17ac76be11f..f1fee122cb7 100644
--- a/src/mesa/drivers/dri/Makefile.am
+++ b/src/mesa/drivers/dri/Makefile.am
@@ -53,6 +53,7 @@ mesa_dri_drivers_la_SOURCES =
 mesa_dri_drivers_la_LDFLAGS = \
         -module -avoid-version -shared \
         -Wl,-Bsymbolic \
+        $(GC_SECTIONS) \
         $()
 mesa_dri_drivers_la_LIBADD = \
         ../../libmesa.la \
diff --git a/src/mesa/drivers/osmesa/Makefile.am b/src/mesa/drivers/osmesa/Makefile.am
index cfab70216ac..b133fd67922 100644
--- a/src/mesa/drivers/osmesa/Makefile.am
+++ b/src/mesa/drivers/osmesa/Makefile.am
@@ -39,6 +39,7 @@ lib@OSMESA_LIB@_la_LDFLAGS = \
 	-module \
 	-no-undefined \
 	-version-number @OSMESA_VERSION@ \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 
diff --git a/src/mesa/drivers/x11/Makefile.am b/src/mesa/drivers/x11/Makefile.am
index 4c63d59a57c..2b38ad31101 100644
--- a/src/mesa/drivers/x11/Makefile.am
+++ b/src/mesa/drivers/x11/Makefile.am
@@ -64,6 +64,7 @@ lib@GL_LIB@_la_LIBADD = \
 lib@GL_LIB@_la_LDFLAGS = \
 	-no-undefined \
 	-version-number $(GL_MAJOR):$(GL_MINOR):$(GL_PATCH) \
+	$(GC_SECTIONS) \
 	-Wl,--no-undefined
 
 include $(top_srcdir)/install-lib-links.mk