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Message-ID: <20150525104708.GB30252@gmail.com>
Date: Mon, 25 May 2015 12:47:09 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Martin Liška <mliska@...e.cz>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
Paul Mackerras <paulus@...ba.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH] perf: fix wrong DEBUG configuration
* Martin Liška <mliska@...e.cz> wrote:
> Currently, GCC optimizes -O6 same as -O3 level, thus change the value
> to -O6.
s/to -O6
to -O3
> Right optimize debugging experience is given by passing -Og to
> compiler. Assign default value for pointers that are identified by
> compiler as non-initialized.
s/Right optimize debugging experience is given/
Correct debugging experience is given/
s/identified by compiler
identified by the compiler
> ifeq ($(DEBUG),0)
> - CFLAGS += -O6
> + CFLAGS += -O3
> +else
> + CFLAGS += $(call cc-option,-Og,-O0)
> endif
> +# try-run
> +# Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
> +# Exit code chooses option. "$$TMP" is can be used as temporary file and
> +# is automatically cleaned up.
> +try-run = $(shell set -e; \
> + TMP="$(TMPOUT).$$$$.tmp"; \
> + TMPO="$(TMPOUT).$$$$.o"; \
> + if ($(1)) >/dev/null 2>&1; \
> + then echo "$(2)"; \
> + else echo "$(3)"; \
> + fi; \
> + rm -f "$$TMP" "$$TMPO")
> +
> +# cc-option
> +# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
> +
> +cc-option = $(call try-run,\
> + $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
Looks good to me!
Acked-by: Ingo Molnar <mingo@...nel.org>
Thanks,
Ingo
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