From: Doug Goldstein <cardoe@cardoe.com>
Date: Tue, 13 Mar 2018 04:06:51 +0000 (-0500)
Subject: tools: detect appropriate debug optimization level
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~414
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=b43501451733193b265de30fd79a764363a2a473;p=xen.git

tools: detect appropriate debug optimization level

When building debug use -Og as the optimization level if its available,
otherwise retain the use of -O0. -Og has been added by GCC to enable all
optimizations that to not affect debugging while retaining full
debugability.

Signed-off-by: Doug Goldstein <cardoe@cardoe.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---

diff --git a/tools/Rules.mk b/tools/Rules.mk
index 296b722372..3848bcf1f7 100644
--- a/tools/Rules.mk
+++ b/tools/Rules.mk
@@ -164,8 +164,13 @@ LDLIBS_libxenvchan = $(SHDEPS_libxenvchan) $(XEN_LIBVCHAN)/libxenvchan$(libexten
 SHLIB_libxenvchan  = $(SHDEPS_libxenvchan) -Wl,-rpath-link=$(XEN_LIBVCHAN)
 
 ifeq ($(debug),y)
-# Disable optimizations
-CFLAGS += -O0 -fno-omit-frame-pointer
+CFLAGS += -fno-omit-frame-pointer
+# Use optimizations compatible with debugging otherwise disable optimizations
+ifneq ($(call cc-option,$(CC),-Og,n),n)
+CFLAGS += -Og
+else
+CFLAGS += -O0
+endif
 # But allow an override to -O0 in case Python enforces -D_FORTIFY_SOURCE=<n>.
 PY_CFLAGS += $(PY_NOOPT_CFLAGS)
 else