When compiling for windows-arm64 using clang-15, it reports a sometimes
uninitialized variable. This seems to be a false positive, as a default
case guards switch expressions, preventing to return an uninitialized
value, but clang seems unhappy with assert definition.
Setting the rnd variable to zero does not hurt anyway.
../target/ppc/dfp_helper.c:141:13: error: variable 'rnd' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] assert(0); /* cannot get here */ ^~~~~~~~~
../include/qemu/osdep.h:229:20: note: expanded from macro 'assert' #define assert(x) g_assert(x) ^~~~~~~~~~~
/clangarm64/bin/../include/glib-2.0/glib/gtestutils.h:235:49: note: expanded from macro 'g_assert' if G_LIKELY (expr) ; else \
^~~~~~~~~~~~~~~
/clangarm64/bin/../include/glib-2.0/glib/gmacros.h:1186:25: note: expanded from macro 'G_LIKELY'
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../target/ppc/dfp_helper.c:144:42: note: uninitialized use occurs here
decContextSetRounding(&dfp->context, rnd);
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
---
target/ppc/dfp_helper.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c
index cc024316d5..0b4b280683 100644
--- a/target/ppc/dfp_helper.c
+++ b/target/ppc/dfp_helper.c
@@ -69,7 +69,7 @@ struct PPC_DFP {
static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
{
- enum rounding rnd;
+ enum rounding rnd = 0;
switch ((fpscr & FP_DRN) >> FPSCR_DRN0) {
case 0:
@@ -106,7 +106,7 @@ static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
static void dfp_set_round_mode_from_immediate(uint8_t r, uint8_t rmc,
struct PPC_DFP *dfp)
{
- enum rounding rnd;
+ enum rounding rnd = 0;
if (r == 0) {
switch (rmc & 3) {
case 0:
--
2.30.2On 2/13/23 06:13, Pierrick Bouvier wrote: > When compiling for windows-arm64 using clang-15, it reports a sometimes > uninitialized variable. This seems to be a false positive, as a default > case guards switch expressions, preventing to return an uninitialized > value, but clang seems unhappy with assert definition. > > Setting the rnd variable to zero does not hurt anyway. > > ../target/ppc/dfp_helper.c:141:13: error: variable 'rnd' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] assert(0); /* cannot get here */ ^~~~~~~~~ > ../include/qemu/osdep.h:229:20: note: expanded from macro 'assert' #define assert(x) g_assert(x) ^~~~~~~~~~~ > /clangarm64/bin/../include/glib-2.0/glib/gtestutils.h:235:49: note: expanded from macro 'g_assert' if G_LIKELY (expr) ; else \ > ^~~~~~~~~~~~~~~ > /clangarm64/bin/../include/glib-2.0/glib/gmacros.h:1186:25: note: expanded from macro 'G_LIKELY' > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > ../target/ppc/dfp_helper.c:144:42: note: uninitialized use occurs here > decContextSetRounding(&dfp->context, rnd); I think the problem is with assert(0) not being seen to terminate. Replace these with g_assert_not_reached(). r~
On 2/14/23 19:10, Richard Henderson wrote: > On 2/13/23 06:13, Pierrick Bouvier wrote: >> When compiling for windows-arm64 using clang-15, it reports a sometimes >> uninitialized variable. This seems to be a false positive, as a default >> case guards switch expressions, preventing to return an uninitialized >> value, but clang seems unhappy with assert definition. >> >> Setting the rnd variable to zero does not hurt anyway. >> >> ../target/ppc/dfp_helper.c:141:13: error: variable 'rnd' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] assert(0); /* cannot get here */ ^~~~~~~~~ >> ../include/qemu/osdep.h:229:20: note: expanded from macro 'assert' #define assert(x) g_assert(x) ^~~~~~~~~~~ >> /clangarm64/bin/../include/glib-2.0/glib/gtestutils.h:235:49: note: expanded from macro 'g_assert' if G_LIKELY (expr) ; else \ >> ^~~~~~~~~~~~~~~ >> /clangarm64/bin/../include/glib-2.0/glib/gmacros.h:1186:25: note: expanded from macro 'G_LIKELY' >> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> ../target/ppc/dfp_helper.c:144:42: note: uninitialized use occurs here >> decContextSetRounding(&dfp->context, rnd); > > I think the problem is with assert(0) not being seen to terminate. > Replace these with g_assert_not_reached(). > Indeed, that solves the issue. Thanks for the suggestion, I'll use this instead. > > r~ >
On 13/2/23 17:13, Pierrick Bouvier wrote:
> When compiling for windows-arm64 using clang-15, it reports a sometimes
> uninitialized variable. This seems to be a false positive, as a default
> case guards switch expressions, preventing to return an uninitialized
> value, but clang seems unhappy with assert definition.
>
> Setting the rnd variable to zero does not hurt anyway.
>
> ../target/ppc/dfp_helper.c:141:13: error: variable 'rnd' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] assert(0); /* cannot get here */ ^~~~~~~~~
> ../include/qemu/osdep.h:229:20: note: expanded from macro 'assert' #define assert(x) g_assert(x) ^~~~~~~~~~~
> /clangarm64/bin/../include/glib-2.0/glib/gtestutils.h:235:49: note: expanded from macro 'g_assert' if G_LIKELY (expr) ; else \
> ^~~~~~~~~~~~~~~
> /clangarm64/bin/../include/glib-2.0/glib/gmacros.h:1186:25: note: expanded from macro 'G_LIKELY'
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../target/ppc/dfp_helper.c:144:42: note: uninitialized use occurs here
> decContextSetRounding(&dfp->context, rnd);
>
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
> target/ppc/dfp_helper.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c
> index cc024316d5..0b4b280683 100644
> --- a/target/ppc/dfp_helper.c
> +++ b/target/ppc/dfp_helper.c
> @@ -69,7 +69,7 @@ struct PPC_DFP {
>
> static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
> {
> - enum rounding rnd;
> + enum rounding rnd = 0;
>
> switch ((fpscr & FP_DRN) >> FPSCR_DRN0) {
> case 0:
> @@ -106,7 +106,7 @@ static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
> static void dfp_set_round_mode_from_immediate(uint8_t r, uint8_t rmc,
> struct PPC_DFP *dfp)
> {
> - enum rounding rnd;
> + enum rounding rnd = 0;
Could DEC_ROUND_DEFAULT be clearer?
On 2/14/23 08:14, Philippe Mathieu-Daudé wrote:
> On 13/2/23 17:13, Pierrick Bouvier wrote:
>> When compiling for windows-arm64 using clang-15, it reports a sometimes
>> uninitialized variable. This seems to be a false positive, as a default
>> case guards switch expressions, preventing to return an uninitialized
>> value, but clang seems unhappy with assert definition.
>>
>> Setting the rnd variable to zero does not hurt anyway.
>>
>> ../target/ppc/dfp_helper.c:141:13: error: variable 'rnd' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] assert(0); /* cannot get here */ ^~~~~~~~~
>> ../include/qemu/osdep.h:229:20: note: expanded from macro 'assert' #define assert(x) g_assert(x) ^~~~~~~~~~~
>> /clangarm64/bin/../include/glib-2.0/glib/gtestutils.h:235:49: note: expanded from macro 'g_assert' if G_LIKELY (expr) ; else \
>> ^~~~~~~~~~~~~~~
>> /clangarm64/bin/../include/glib-2.0/glib/gmacros.h:1186:25: note: expanded from macro 'G_LIKELY'
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> ../target/ppc/dfp_helper.c:144:42: note: uninitialized use occurs here
>> decContextSetRounding(&dfp->context, rnd);
>>
>> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
>> ---
>> target/ppc/dfp_helper.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c
>> index cc024316d5..0b4b280683 100644
>> --- a/target/ppc/dfp_helper.c
>> +++ b/target/ppc/dfp_helper.c
>> @@ -69,7 +69,7 @@ struct PPC_DFP {
>>
>> static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
>> {
>> - enum rounding rnd;
>> + enum rounding rnd = 0;
>>
>> switch ((fpscr & FP_DRN) >> FPSCR_DRN0) {
>> case 0:
>> @@ -106,7 +106,7 @@ static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
>> static void dfp_set_round_mode_from_immediate(uint8_t r, uint8_t rmc,
>> struct PPC_DFP *dfp)
>> {
>> - enum rounding rnd;
>> + enum rounding rnd = 0;
>
> Could DEC_ROUND_DEFAULT be clearer?
>
I missed that macro definition, and that seems like a good default
value. I'll change to this.
On 2/13/23 17:13, Pierrick Bouvier wrote:
> When compiling for windows-arm64 using clang-15, it reports a sometimes
> uninitialized variable. This seems to be a false positive, as a default
> case guards switch expressions, preventing to return an uninitialized
> value, but clang seems unhappy with assert definition.
>
> Setting the rnd variable to zero does not hurt anyway.
>
> ../target/ppc/dfp_helper.c:141:13: error: variable 'rnd' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized] assert(0); /* cannot get here */ ^~~~~~~~~
> ../include/qemu/osdep.h:229:20: note: expanded from macro 'assert' #define assert(x) g_assert(x) ^~~~~~~~~~~
> /clangarm64/bin/../include/glib-2.0/glib/gtestutils.h:235:49: note: expanded from macro 'g_assert' if G_LIKELY (expr) ; else \
> ^~~~~~~~~~~~~~~
> /clangarm64/bin/../include/glib-2.0/glib/gmacros.h:1186:25: note: expanded from macro 'G_LIKELY'
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../target/ppc/dfp_helper.c:144:42: note: uninitialized use occurs here
> decContextSetRounding(&dfp->context, rnd);
>
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Thanks,
C.
> ---
> target/ppc/dfp_helper.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c
> index cc024316d5..0b4b280683 100644
> --- a/target/ppc/dfp_helper.c
> +++ b/target/ppc/dfp_helper.c
> @@ -69,7 +69,7 @@ struct PPC_DFP {
>
> static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
> {
> - enum rounding rnd;
> + enum rounding rnd = 0;
>
> switch ((fpscr & FP_DRN) >> FPSCR_DRN0) {
> case 0:
> @@ -106,7 +106,7 @@ static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
> static void dfp_set_round_mode_from_immediate(uint8_t r, uint8_t rmc,
> struct PPC_DFP *dfp)
> {
> - enum rounding rnd;
> + enum rounding rnd = 0;
> if (r == 0) {
> switch (rmc & 3) {
> case 0:
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