[PATCH v3 0/9] misc: Trivial static code analyzer fixes

[PATCH v3 0/9] misc: Trivial static code analyzer fixes

[Philippe Mathieu-Daudé]

Fix trivial warnings reported by the Clang static code analyzer.

Only patch #2 'blockdev: Remove dead assignment' misses review.

The official Clang static code analyzer documentation is on:
https://clang-analyzer.llvm.org/

On Fedora I simply used it as:

  $ sudo dnf install clang-analyzer
  $ ../configure
  $ scan-build make

Since v2:
- Based on lvivier/trivial-patches-for-5.1
- Removed dup patches from Kuhn Chenqun
Since v1:
- Addressed Markus/Zoltan/Aleksandar review comments

Philippe Mathieu-Daudé (9):
  block: Avoid dead assignment
  blockdev: Remove dead assignment
  hw/i2c/pm_smbus: Remove dead assignment
  hw/input/adb-kbd: Remove dead assignment
  hw/ide/sii3112: Remove dead assignment
  hw/isa/i82378: Remove dead assignment
  hw/gpio/aspeed_gpio: Remove dead assignment
  hw/timer/stm32f2xx_timer: Remove dead assignment
  hw/timer/pxa2xx_timer: Add assertion to silent static analyzer warning

 block.c                    | 2 +-
 blockdev.c                 | 2 +-
 hw/gpio/aspeed_gpio.c      | 2 +-
 hw/i2c/pm_smbus.c          | 1 -
 hw/ide/sii3112.c           | 5 +++--
 hw/input/adb-kbd.c         | 6 +-----
 hw/isa/i82378.c            | 8 ++++----
 hw/timer/pxa2xx_timer.c    | 1 +
 hw/timer/stm32f2xx_timer.c | 1 -
 9 files changed, 12 insertions(+), 16 deletions(-)

-- 
2.21.1

[PATCH v3 1/9] block: Avoid dead assignment

[Philippe Mathieu-Daudé]

Fix warning reported by Clang static code analyzer:

  block.c:3167:5: warning: Value stored to 'ret' is never read
      ret = bdrv_fill_options(&options, filename, &flags, &local_err);
      ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: 462f5bcf6
Reported-by: Clang Static Analyzer
Suggested-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block.c b/block.c
index 2e3905c99e..27e7e0e3ab 100644
--- a/block.c
+++ b/block.c
@@ -3171,7 +3171,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
     }
 
     ret = bdrv_fill_options(&options, filename, &flags, &local_err);
-    if (local_err) {
+    if (ret < 0) {
         goto fail;
     }
 
-- 
2.21.1

Re: [PATCH v3 1/9] block: Avoid dead assignment

[Max Reitz]

[-- Attachment #1.1: Type: text/plain, Size: 686 bytes --]

On 22.04.20 15:31, Philippe Mathieu-Daudé wrote:
> Fix warning reported by Clang static code analyzer:
> 
>   block.c:3167:5: warning: Value stored to 'ret' is never read
>       ret = bdrv_fill_options(&options, filename, &flags, &local_err);
>       ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Fixes: 462f5bcf6
> Reported-by: Clang Static Analyzer
> Suggested-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  block.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[PATCH v3 2/9] blockdev: Remove dead assignment

[Philippe Mathieu-Daudé]

Fix warning reported by Clang static code analyzer:

    CC      blockdev.o
  blockdev.c:2744:5: warning: Value stored to 'ret' is never read
      ret = blk_truncate(blk, size, false, PREALLOC_MODE_OFF, errp);
      ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 blockdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/blockdev.c b/blockdev.c
index fa8630cb41..6effd5afaa 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2741,7 +2741,7 @@ void qmp_block_resize(bool has_device, const char *device,
     }
 
     bdrv_drained_begin(bs);
-    ret = blk_truncate(blk, size, false, PREALLOC_MODE_OFF, errp);
+    blk_truncate(blk, size, false, PREALLOC_MODE_OFF, errp);
     bdrv_drained_end(bs);
 
 out:
-- 
2.21.1

Re: [PATCH v3 2/9] blockdev: Remove dead assignment

[Max Reitz]

[-- Attachment #1.1: Type: text/plain, Size: 579 bytes --]

On 22.04.20 15:31, Philippe Mathieu-Daudé wrote:
> Fix warning reported by Clang static code analyzer:
> 
>     CC      blockdev.o
>   blockdev.c:2744:5: warning: Value stored to 'ret' is never read
>       ret = blk_truncate(blk, size, false, PREALLOC_MODE_OFF, errp);
>       ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Reported-by: Clang Static Analyzer
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  blockdev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

[PATCH v3 3/9] hw/i2c/pm_smbus: Remove dead assignment

[Philippe Mathieu-Daudé]

Fix warning reported by Clang static code analyzer:

    CC      hw/i2c/pm_smbus.o
  hw/i2c/pm_smbus.c:187:17: warning: Value stored to 'ret' is never read
                  ret = 0;
                  ^     ~

Reported-by: Clang Static Analyzer
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/i2c/pm_smbus.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/i2c/pm_smbus.c b/hw/i2c/pm_smbus.c
index 36994ff585..4728540c37 100644
--- a/hw/i2c/pm_smbus.c
+++ b/hw/i2c/pm_smbus.c
@@ -184,7 +184,6 @@ static void smb_transaction(PMSMBus *s)
                 s->smb_stat |= STS_HOST_BUSY | STS_BYTE_DONE;
                 s->smb_data[0] = s->smb_blkdata;
                 s->smb_index = 0;
-                ret = 0;
             }
             goto out;
         }
-- 
2.21.1

[PATCH v3 4/9] hw/input/adb-kbd: Remove dead assignment

[Philippe Mathieu-Daudé]

Since commit 5a1f49718 the 'olen' variable is not really
used. Remove it to fix a warning reported by Clang static
code analyzer:

    CC      hw/input/adb-kbd.o
  hw/input/adb-kbd.c:200:5: warning: Value stored to 'olen' is never read
      olen = 0;
      ^      ~

Fixes: 5a1f49718 (adb: add support for QKeyCode)
Reported-by: Clang Static Analyzer
Suggested-by: BALATON Zoltan <balaton@eik.bme.hu>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/input/adb-kbd.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/hw/input/adb-kbd.c b/hw/input/adb-kbd.c
index 0ba8207589..a6d5c9b7c9 100644
--- a/hw/input/adb-kbd.c
+++ b/hw/input/adb-kbd.c
@@ -195,9 +195,7 @@ static int adb_kbd_poll(ADBDevice *d, uint8_t *obuf)
 {
     KBDState *s = ADB_KEYBOARD(d);
     int keycode;
-    int olen;
 
-    olen = 0;
     if (s->count == 0) {
         return 0;
     }
@@ -216,7 +214,6 @@ static int adb_kbd_poll(ADBDevice *d, uint8_t *obuf)
     if (keycode == 0x7f) {
         obuf[0] = 0x7f;
         obuf[1] = 0x7f;
-        olen = 2;
     } else {
         obuf[0] = keycode;
         /* NOTE: the power key key-up is the two byte sequence 0xff 0xff;
@@ -224,10 +221,9 @@ static int adb_kbd_poll(ADBDevice *d, uint8_t *obuf)
          * byte, but choose not to bother.
          */
         obuf[1] = 0xff;
-        olen = 2;
     }
 
-    return olen;
+    return 2;
 }
 
 static int adb_kbd_request(ADBDevice *d, uint8_t *obuf,
-- 
2.21.1

[PATCH v3 5/9] hw/ide/sii3112: Remove dead assignment

[Philippe Mathieu-Daudé]

Fix warning reported by Clang static code analyzer:

    CC      hw/ide/sii3112.o
  hw/ide/sii3112.c:204:9: warning: Value stored to 'val' is never read
          val = 0;
          ^     ~

Fixes: a9dd6604
Reported-by: Clang Static Analyzer
Reviewed-by: BALATON Zoltan <balaton@eik.bme.hu>
Acked-by: John Snow <jsnow@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/ide/sii3112.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/ide/sii3112.c b/hw/ide/sii3112.c
index d69079c3d9..94d2b57f95 100644
--- a/hw/ide/sii3112.c
+++ b/hw/ide/sii3112.c
@@ -42,7 +42,7 @@ static uint64_t sii3112_reg_read(void *opaque, hwaddr addr,
                                 unsigned int size)
 {
     SiI3112PCIState *d = opaque;
-    uint64_t val = 0;
+    uint64_t val;
 
     switch (addr) {
     case 0x00:
@@ -126,6 +126,7 @@ static uint64_t sii3112_reg_read(void *opaque, hwaddr addr,
         break;
     default:
         val = 0;
+        break;
     }
     trace_sii3112_read(size, addr, val);
     return val;
@@ -201,7 +202,7 @@ static void sii3112_reg_write(void *opaque, hwaddr addr,
         d->regs[1].sien = (val >> 16) & 0x3eed;
         break;
     default:
-        val = 0;
+        break;
     }
 }
 
-- 
2.21.1

[PATCH v3 6/9] hw/isa/i82378: Remove dead assignment

[Philippe Mathieu-Daudé]

Rename the unique variable assigned as 'pit' which better
represents what it holds, to fix a warning reported by the
Clang static code analyzer:

    CC      hw/isa/i82378.o
  hw/isa/i82378.c:108:5: warning: Value stored to 'isa' is never read
      isa = isa_create_simple(isabus, "i82374");
      ^     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reported-by: Clang Static Analyzer
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/isa/i82378.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/isa/i82378.c b/hw/isa/i82378.c
index dcb6b479ea..d9e6c7fa00 100644
--- a/hw/isa/i82378.c
+++ b/hw/isa/i82378.c
@@ -67,7 +67,7 @@ static void i82378_realize(PCIDevice *pci, Error **errp)
     I82378State *s = I82378(dev);
     uint8_t *pci_conf;
     ISABus *isabus;
-    ISADevice *isa;
+    ISADevice *pit;
 
     pci_conf = pci->config;
     pci_set_word(pci_conf + PCI_COMMAND,
@@ -99,13 +99,13 @@ static void i82378_realize(PCIDevice *pci, Error **errp)
     isa_bus_irqs(isabus, s->i8259);
 
     /* 1 82C54 (pit) */
-    isa = i8254_pit_init(isabus, 0x40, 0, NULL);
+    pit = i8254_pit_init(isabus, 0x40, 0, NULL);
 
     /* speaker */
-    pcspk_init(isabus, isa);
+    pcspk_init(isabus, pit);
 
     /* 2 82C37 (dma) */
-    isa = isa_create_simple(isabus, "i82374");
+    isa_create_simple(isabus, "i82374");
 }
 
 static void i82378_init(Object *obj)
-- 
2.21.1

[PATCH v3 7/9] hw/gpio/aspeed_gpio: Remove dead assignment

[Philippe Mathieu-Daudé]

Fix warning reported by Clang static code analyzer:

  hw/gpio/aspeed_gpio.c:717:18: warning: Value stored to 'g_idx' during its initialization is never read
      int set_idx, g_idx = *group_idx;
                   ^~~~~   ~~~~~~~~~~

Reported-by: Clang Static Analyzer
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/gpio/aspeed_gpio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/gpio/aspeed_gpio.c b/hw/gpio/aspeed_gpio.c
index 41e11ea9b0..bd19db31f4 100644
--- a/hw/gpio/aspeed_gpio.c
+++ b/hw/gpio/aspeed_gpio.c
@@ -714,7 +714,7 @@ static void aspeed_gpio_write(void *opaque, hwaddr offset, uint64_t data,
 static int get_set_idx(AspeedGPIOState *s, const char *group, int *group_idx)
 {
     AspeedGPIOClass *agc = ASPEED_GPIO_GET_CLASS(s);
-    int set_idx, g_idx = *group_idx;
+    int set_idx, g_idx;
 
     for (set_idx = 0; set_idx < agc->nr_gpio_sets; set_idx++) {
         const GPIOSetProperties *set_props = &agc->props[set_idx];
-- 
2.21.1

[PATCH v3 8/9] hw/timer/stm32f2xx_timer: Remove dead assignment

[Philippe Mathieu-Daudé]

Fix warning reported by Clang static code analyzer:

    CC      hw/timer/stm32f2xx_timer.o
  hw/timer/stm32f2xx_timer.c:225:9: warning: Value stored to 'value' is never read
          value = timer_val;
          ^       ~~~~~~~~~

Reported-by: Clang Static Analyzer
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/timer/stm32f2xx_timer.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/timer/stm32f2xx_timer.c b/hw/timer/stm32f2xx_timer.c
index 06ec8a02c2..ba8694dcd3 100644
--- a/hw/timer/stm32f2xx_timer.c
+++ b/hw/timer/stm32f2xx_timer.c
@@ -222,7 +222,6 @@ static void stm32f2xx_timer_write(void *opaque, hwaddr offset,
     case TIM_PSC:
         timer_val = stm32f2xx_ns_to_ticks(s, now) - s->tick_offset;
         s->tim_psc = value & 0xFFFF;
-        value = timer_val;
         break;
     case TIM_CNT:
         timer_val = value;
-- 
2.21.1

[PATCH v3 9/9] hw/timer/pxa2xx_timer: Add assertion to silent static analyzer warning

[Philippe Mathieu-Daudé]

pxa2xx_timer_tick4() takes an opaque pointer, then calls
pxa2xx_timer_update4(), so the static analyzer can not
verify that the 'n < 8':

  425 static void pxa2xx_timer_tick4(void *opaque)
  426 {
  427     PXA2xxTimer4 *t = (PXA2xxTimer4 *) opaque;
  428     PXA2xxTimerInfo *i = (PXA2xxTimerInfo *) t->tm.info;
  429
  430     pxa2xx_timer_tick(&t->tm);
  433     if (t->control & (1 << 6))
  434         pxa2xx_timer_update4(i, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL), t->tm.num - 4);

  135 static void pxa2xx_timer_update4(void *opaque, uint64_t now_qemu, int n)
  136 {
  137     PXA2xxTimerInfo *s = (PXA2xxTimerInfo *) opaque;
  140     static const int counters[8] = { 0, 0, 0, 0, 4, 4, 6, 6 };
  142
  143     if (s->tm4[n].control & (1 << 7))
  144         counter = n;
  145     else
  146         counter = counters[n];

Add an assert() to give the static analyzer a hint, this fixes a
warning reported by Clang static code analyzer:

    CC      hw/timer/pxa2xx_timer.o
  hw/timer/pxa2xx_timer.c:146:17: warning: Assigned value is garbage or undefined
          counter = counters[n];
                  ^ ~~~~~~~~~~~

Reported-by: Clang Static Analyzer
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/timer/pxa2xx_timer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/timer/pxa2xx_timer.c b/hw/timer/pxa2xx_timer.c
index cd172cc1e9..944c165889 100644
--- a/hw/timer/pxa2xx_timer.c
+++ b/hw/timer/pxa2xx_timer.c
@@ -140,6 +140,7 @@ static void pxa2xx_timer_update4(void *opaque, uint64_t now_qemu, int n)
     static const int counters[8] = { 0, 0, 0, 0, 4, 4, 6, 6 };
     int counter;
 
+    assert(n < ARRAY_SIZE(counters));
     if (s->tm4[n].control & (1 << 7))
         counter = n;
     else
-- 
2.21.1

Re: [PATCH v3 0/9] misc: Trivial static code analyzer fixes

[Philippe Mathieu-Daudé]

On 4/22/20 3:31 PM, Philippe Mathieu-Daudé wrote:
> Fix trivial warnings reported by the Clang static code analyzer.
> 
> Only patch #2 'blockdev: Remove dead assignment' misses review.

Thanks to Max this series is now fully reviewed, so... ping?

> 
> The official Clang static code analyzer documentation is on:
> https://clang-analyzer.llvm.org/
> 
> On Fedora I simply used it as:
> 
>    $ sudo dnf install clang-analyzer
>    $ ../configure
>    $ scan-build make
> 
> Since v2:
> - Based on lvivier/trivial-patches-for-5.1
> - Removed dup patches from Kuhn Chenqun
> Since v1:
> - Addressed Markus/Zoltan/Aleksandar review comments
> 
> Philippe Mathieu-Daudé (9):
>    block: Avoid dead assignment
>    blockdev: Remove dead assignment
>    hw/i2c/pm_smbus: Remove dead assignment
>    hw/input/adb-kbd: Remove dead assignment
>    hw/ide/sii3112: Remove dead assignment
>    hw/isa/i82378: Remove dead assignment
>    hw/gpio/aspeed_gpio: Remove dead assignment
>    hw/timer/stm32f2xx_timer: Remove dead assignment
>    hw/timer/pxa2xx_timer: Add assertion to silent static analyzer warning
> 
>   block.c                    | 2 +-
>   blockdev.c                 | 2 +-
>   hw/gpio/aspeed_gpio.c      | 2 +-
>   hw/i2c/pm_smbus.c          | 1 -
>   hw/ide/sii3112.c           | 5 +++--
>   hw/input/adb-kbd.c         | 6 +-----
>   hw/isa/i82378.c            | 8 ++++----
>   hw/timer/pxa2xx_timer.c    | 1 +
>   hw/timer/stm32f2xx_timer.c | 1 -
>   9 files changed, 12 insertions(+), 16 deletions(-)
> 

Re: [PATCH v3 0/9] misc: Trivial static code analyzer fixes

[Laurent Vivier]

Le 22/04/2020 à 15:31, Philippe Mathieu-Daudé a écrit :
> Fix trivial warnings reported by the Clang static code analyzer.
> 
> Only patch #2 'blockdev: Remove dead assignment' misses review.
> 
> The official Clang static code analyzer documentation is on:
> https://clang-analyzer.llvm.org/
> 
> On Fedora I simply used it as:
> 
>   $ sudo dnf install clang-analyzer
>   $ ../configure
>   $ scan-build make
> 
> Since v2:
> - Based on lvivier/trivial-patches-for-5.1
> - Removed dup patches from Kuhn Chenqun
> Since v1:
> - Addressed Markus/Zoltan/Aleksandar review comments
> 
> Philippe Mathieu-Daudé (9):
>   block: Avoid dead assignment
>   blockdev: Remove dead assignment
>   hw/i2c/pm_smbus: Remove dead assignment
>   hw/input/adb-kbd: Remove dead assignment
>   hw/ide/sii3112: Remove dead assignment
>   hw/isa/i82378: Remove dead assignment
>   hw/gpio/aspeed_gpio: Remove dead assignment
>   hw/timer/stm32f2xx_timer: Remove dead assignment
>   hw/timer/pxa2xx_timer: Add assertion to silent static analyzer warning
> 
>  block.c                    | 2 +-
>  blockdev.c                 | 2 +-
>  hw/gpio/aspeed_gpio.c      | 2 +-
>  hw/i2c/pm_smbus.c          | 1 -
>  hw/ide/sii3112.c           | 5 +++--
>  hw/input/adb-kbd.c         | 6 +-----
>  hw/isa/i82378.c            | 8 ++++----
>  hw/timer/pxa2xx_timer.c    | 1 +
>  hw/timer/stm32f2xx_timer.c | 1 -
>  9 files changed, 12 insertions(+), 16 deletions(-)
> 

Applied to my trivial-patches branch.

Thanks,
Laurent