Re: [PATCH] perf: fix wrong DEBUG configuration
From: Martin LiÅka
Date: Mon May 25 2015 - 04:04:34 EST
On 05/22/2015 09:02 AM, Ingo Molnar wrote:
* Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
Em Wed, May 20, 2015 at 06:16:51PM +0200, Martin LiÅka escreveu:
On 05/20/2015 04:55 PM, Ingo Molnar wrote:
* Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:
So the rule has been: What are the kernel requirements for the
toolchain? tools/perf/ should build with that.
So we could use -Og if it works, like Kbuild does it:
KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
the 'cc-option' Make function does some magic of silently calling GCC
with that option and observing the result.
See:
scripts/Kbuild.include:cc-option = $(call try-run,\
I am sorry, I did mistake in understanding of DEBUG variable.
Following patch should be fixed, except missing auto-detection
of -Og option.
Unfortunately, following hunk does not work, no -Ox is added to CFLAGS?
-- CFLAGS += -Og
++ CFLAGS += $(call cc-option,-Og,-O0)
I don't know if we have this cc-option, perhaps Ingo is suggesting
we get it in tools/build/? Or include scripts/Kbuild.include and
then use it?
I.e. we have checks to see if we can use, for instance
-fstack-protector-all, see tools/build/feature/Makefile, using this
cc-option thing, importing it from Kbuild would solve the issue at
hand in a definitive way and in line with what we have been
pursuing: to make the tools/ build system be based on Kbuild.
So I'd suggest copying any necessary functions instead of outright
including all of Kbuild in the tooling build system which creates
non-trivial dependencies that is not necessarily tested as thoroughly
on the kbuild side as on the tooling side.
Thanks,
Ingo
Hi.
Thanks for advice, I copied necessary functions to include/utilities.mak.
Following patch works for, tested both with a compiler capable of -Og and
a not capable one.
Thanks,
Martin
Currently, GCC optimizes -O6 same as -O3 level, thus change the value
to -O6.
Right optimize debugging experience is given by passing -Og to compiler.
Assign default value for pointers that are identified by compiler as
non-initialized.
Signed-off-by: Martin Liska <mliska@xxxxxxx>
---
tools/perf/arch/common.c | 2 +-
tools/perf/config/Makefile | 4 +++-
tools/perf/config/utilities.mak | 19 +++++++++++++++++++
tools/perf/util/symbol.c | 2 +-
tools/perf/util/trace-event-parse.c | 2 +-
5 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/tools/perf/arch/common.c b/tools/perf/arch/common.c
index 49776f1..b7bb42c 100644
--- a/tools/perf/arch/common.c
+++ b/tools/perf/arch/common.c
@@ -61,7 +61,7 @@ const char *const mips_triplets[] = {
static bool lookup_path(char *name)
{
bool found = false;
- char *path, *tmp;
+ char *path, *tmp = NULL;
char buf[PATH_MAX];
char *env = getenv("PATH");
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index e3b3724..47e4ae1 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -129,7 +129,9 @@ ifndef DEBUG
endif
ifeq ($(DEBUG),0)
- CFLAGS += -O6
+ CFLAGS += -O3
+else
+ CFLAGS += $(call cc-option,-Og,-O0)
endif
ifdef PARSER_DEBUG
diff --git a/tools/perf/config/utilities.mak b/tools/perf/config/utilities.mak
index c16ce83..0ebef09 100644
--- a/tools/perf/config/utilities.mak
+++ b/tools/perf/config/utilities.mak
@@ -177,3 +177,22 @@ $(if $($(1)),$(call _ge_attempt,$($(1)),$(1)),$(call _ge_attempt,$(2)))
endef
_ge_attempt = $(if $(get-executable),$(get-executable),$(call _gea_err,$(2)))
_gea_err = $(if $(1),$(error Please set '$(1)' appropriately))
+
+# 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))
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 82a31fd..a19fbd4 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -400,7 +400,7 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
const char *name)
{
struct rb_node *n;
- struct symbol_name_rb_node *s;
+ struct symbol_name_rb_node *s = NULL;
if (symbols == NULL)
return NULL;
diff --git a/tools/perf/util/trace-event-parse.c b/tools/perf/util/trace-event-parse.c
index 25d6c73..d495741 100644
--- a/tools/perf/util/trace-event-parse.c
+++ b/tools/perf/util/trace-event-parse.c
@@ -173,7 +173,7 @@ void parse_ftrace_printk(struct pevent *pevent,
char *line;
char *next = NULL;
char *addr_str;
- char *fmt;
+ char *fmt = NULL;
line = strtok_r(file, "\n", &next);
while (line) {
--
2.1.4