| Message ID | 1461077836-7735-1-git-send-email-cardoe@cardoe.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Doug Goldstein writes ("[PATCH v2] 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.
...
> -CFLAGS += -O0 -g3
> +CFLAGS += $(call cc-option,$(CC),-Og,-O0)
> +CFLAGS += -g3
I think CFLAGS is a variable which is expanded late, at each reference
site - a `recursively expanded' variable.
The result is that the call to the compiler to test the -Og flag
(implied by cc-option) will be executed potentially for every C source
code file!
I think you need to use cc-option-add.
Ian.
diff --git a/tools/Rules.mk b/tools/Rules.mk index 9ef0b47..4162bd9 100644 --- a/tools/Rules.mk +++ b/tools/Rules.mk @@ -137,7 +137,8 @@ SHLIB_libxenvchan = $(SHDEPS_libxenvchan) -Wl,-rpath-link=$(XEN_LIBVCHAN) ifeq ($(debug),y) # Disable optimizations and enable debugging information for macros -CFLAGS += -O0 -g3 +CFLAGS += $(call cc-option,$(CC),-Og,-O0) +CFLAGS += -g3 # But allow an override to -O0 in case Python enforces -D_FORTIFY_SOURCE=<n>. PY_CFLAGS += $(PY_NOOPT_CFLAGS) endif
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> --- tools/Rules.mk | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)