Re: [Xen-devel] [PATCH v3] tools: detect appropriate debug optimization level

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Tue, Apr 26, 2016 at 09:38:45AM -0500, Doug Goldstein wrote:
> 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@xxxxxxxxxx>
> ---
> change since v2:
> - switch back to cc-option-add to not call cc-option on every invocation
> change since v1:
> - switch to cc-option to only specify -O0 if -Og isn't supported
> ---
>  tools/Rules.mk | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/Rules.mk b/tools/Rules.mk
> index 9ef0b47..1b79a6e 100644
> --- a/tools/Rules.mk
> +++ b/tools/Rules.mk
> @@ -138,6 +138,7 @@ SHLIB_libxenvchan  = $(SHDEPS_libxenvchan) 
> -Wl,-rpath-link=$(XEN_LIBVCHAN)
>  ifeq ($(debug),y)
>  # Disable optimizations and enable debugging information for macros
>  CFLAGS += -O0 -g3
> +$(call cc-option-add,CFLAGS,CC,-Og)
>  # But allow an override to -O0 in case Python enforces -D_FORTIFY_SOURCE=<n>.
>  PY_CFLAGS += $(PY_NOOPT_CFLAGS)
>  endif
> -- 
> 2.7.3

Heh, this patch seems to has a (good) side effect. I will look into
fixing that tomorrow.

make[10]: Entering directory 
'/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit/tcgbios'
gcc   -O1 -fno-omit-frame-pointer -m32 -march=i686 -g -fno-strict-aliasing 
-std=gnu99 -Wall -Wstrict-prototypes -Wdeclaration-after-statement 
-Wno-unused-but-set-variable -Wno-unused-local-typedefs   -O0 -g3 -Og 
-D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__ -MMD -MF 
.tcgbios.o.d -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE 
-fno-optimize-sibling-calls -mno-tls-direct-seg-refs  -Werror 
-fno-stack-protector -fno-exceptions -fno-builtin -msoft-float 
-I/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit/tcgbios/../../../../../tools/include
 -I.. -I../..  -c -o tcgbios.o tcgbios.c 
gcc   -O1 -fno-omit-frame-pointer -m32 -march=i686 -g -fno-strict-aliasing 
-std=gnu99 -Wall -Wstrict-prototypes -Wdeclaration-after-statement 
-Wno-unused-but-set-variable -Wno-unused-local-typedefs   -O0 -g3 -Og 
-D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__ -MMD -MF 
.tpm_drivers.o.d -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE 
-fno-optimize-sibling-calls -mno-tls-direct-seg-refs  -Werror 
-fno-stack-protector -fno-exceptions -fno-builtin -msoft-float 
-I/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit/tcgbios/../../../../../tools/include
 -I.. -I../..  -c -o tpm_drivers.o tpm_drivers.c 
tcgbios.c: In function ‘tcpa_extend_acpi_log’:
tcgbios.c:362:3: error: ‘size’ may be used uninitialized in this function 
[-Werror=maybe-uninitialized]
   memcpy((char *)lasa_last, (char *)entry_ptr, size);
   ^
tcgbios.c: In function ‘HashLogEvent32’:
tcgbios.c:1142:22: error: ‘entry’ may be used uninitialized in this function 
[-Werror=maybe-uninitialized]
    hleo->eventnumber = entry;
                      ^
tcgbios.c:1131:10: error: ‘logdataptr’ may be used uninitialized in this 
function [-Werror=maybe-uninitialized]
    entry = tcpa_extend_acpi_log(logdataptr);
          ^
cc1: all warnings being treated as errors
/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit/tcgbios/../../../../../tools/Rules.mk:192:
 recipe for target 'tcgbios.o' failed
make[10]: *** [tcgbios.o] Error 1
make[10]: Leaving directory 
'/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit/tcgbios'
/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit/../../../../tools/Rules.mk:216:
 recipe for target 'subdir-all-tcgbios' failed
make[9]: *** [subdir-all-tcgbios] Error 2
make[9]: Leaving directory 
'/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit'
/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit/../../../../tools/Rules.mk:211:
 recipe for target 'subdirs-all' failed
make[8]: *** [subdirs-all] Error 2
make[8]: Leaving directory 
'/local/work/COMMITTER/xen.git/tools/firmware/rombios/32bit'
/local/work/COMMITTER/xen.git/tools/firmware/rombios/../../../tools/Rules.mk:216:
 recipe for target 'subdir-all-32bit' failed
make[7]: *** [subdir-all-32bit] Error 2
make[7]: Leaving directory 
'/local/work/COMMITTER/xen.git/tools/firmware/rombios'
/local/work/COMMITTER/xen.git/tools/firmware/rombios/../../../tools/Rules.mk:211:
 recipe for target 'subdirs-all' failed
make[6]: *** [subdirs-all] Error 2
make[6]: Leaving directory 
'/local/work/COMMITTER/xen.git/tools/firmware/rombios'
/local/work/COMMITTER/xen.git/tools/firmware/../../tools/Rules.mk:216: recipe 
for target 'subdir-all-rombios' failed
make[5]: *** [subdir-all-rombios] Error 2
make[5]: Leaving directory '/local/work/COMMITTER/xen.git/tools/firmware'
/local/work/COMMITTER/xen.git/tools/firmware/../../tools/Rules.mk:211: recipe 
for target 'subdirs-all' failed
make[4]: *** [subdirs-all] Error 2
make[4]: Leaving directory '/local/work/COMMITTER/xen.git/tools/firmware'
Makefile:33: recipe for target 'all' failed
make[3]: *** [all] Error 2
make[3]: Leaving directory '/local/work/COMMITTER/xen.git/tools/firmware'
/local/work/COMMITTER/xen.git/tools/../tools/Rules.mk:216: recipe for target 
'subdir-install-firmware' failed
make[2]: *** [subdir-install-firmware] Error 2
make[2]: Leaving directory '/local/work/COMMITTER/xen.git/tools'
/local/work/COMMITTER/xen.git/tools/../tools/Rules.mk:211: recipe for target 
'subdirs-install' failed
make[1]: *** [subdirs-install] Error 2
make[1]: Leaving directory '/local/work/COMMITTER/xen.git/tools'
Makefile:101: recipe for target 'install-tools' failed
make: *** [install-tools] Error 2


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