[PATCH] Disable building libgcc with -O0

[Lei Liu <layliu@gmail.com>]

Link error happens for valgrind when linking unoptimized libgcc.
Libgcc requires symbol _Unwind_Resume defined in libgcc_eh which
in turn requires pulling in entire glibc.  We can't make valgrind
link with glibc due to its design.  So don't build libgcc without
optimizations, so that calls to _Unwind_Resume get eliminated.

Signed-off-by: Lei Liu <lei.liu2@windriver.com>
---
 meta/recipes-devtools/gcc/gcc-cross.inc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/meta/recipes-devtools/gcc/gcc-cross.inc b/meta/recipes-devtools/gcc/gcc-cross.inc
index 25a3142..cf03c08 100644
--- a/meta/recipes-devtools/gcc/gcc-cross.inc
+++ b/meta/recipes-devtools/gcc/gcc-cross.inc
@@ -25,6 +25,15 @@ EXTRA_OECONF_PATHS = " \
 
 ARCH_FLAGS_FOR_TARGET += "-isystem${STAGING_DIR_TARGET}${target_includedir}"
 
+def get_optimization(d):
+    selected_optimization = d.getVar("SELECTED_OPTIMIZATION", True)
+    if base_contains("SELECTED_OPTIMIZATION", "-O0", "x", "", d) == "x":
+        bb.note("libgcc can't be built with -O0, -O2 will be used instead.")
+        return selected_optimization.replace("-O0", "-O2")
+    return selected_optimization
+
+SELECTED_OPTIMIZATION := "${@get_optimization(d)}"
+
 do_configure_prepend () {
 	sed -i 's/BUILD_INFO=info/BUILD_INFO=/' ${S}/gcc/configure
 }
--
1.8.2.1