[PATCH] target/i386: Avoid unreachable variable declaration in mmu_translate()

[PATCH] target/i386: Avoid unreachable variable declaration in mmu_translate()

[Peter Maydell]

Coverity complains (CID 1507880) that the declaration "int error_code;"
in mmu_translate() is unreachable code. Since this is only a declaration,
this isn't actually a bug, but:
 * it's a bear-trap for future changes, because if it was changed to
   include an initialization 'int error_code = foo;' then the
   initialization wouldn't actually happen (being dead code)
 * it's against our coding style, which wants declarations to be
   at the start of blocks
 * it means that anybody reading the code has to go and look up
   exactly what the C rules are for skipping over variable declarations
   using a goto

Move the declaration to the top of the function.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/i386/tcg/sysemu/excp_helper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/i386/tcg/sysemu/excp_helper.c b/target/i386/tcg/sysemu/excp_helper.c
index e87f90dbe3c..b5f0abffa3d 100644
--- a/target/i386/tcg/sysemu/excp_helper.c
+++ b/target/i386/tcg/sysemu/excp_helper.c
@@ -147,6 +147,7 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in,
     hwaddr pte_addr, paddr;
     uint32_t pkr;
     int page_size;
+    int error_code;
 
  restart_all:
     rsvd_mask = ~MAKE_64BIT_MASK(0, env_archcpu(env)->phys_bits);
@@ -467,7 +468,6 @@ do_check_protect_pse36:
     out->page_size = page_size;
     return true;
 
-    int error_code;
  do_fault_rsvd:
     error_code = PG_ERROR_RSVD_MASK;
     goto do_fault_cont;
-- 
2.34.1

Re: [PATCH] target/i386: Avoid unreachable variable declaration in mmu_translate()

[Paolo Bonzini]

Queued, thanks.

Paolo

Re: [PATCH] target/i386: Avoid unreachable variable declaration in mmu_translate()

[Philippe Mathieu-Daudé]

On 6/4/23 17:59, Peter Maydell wrote:
> Coverity complains (CID 1507880) that the declaration "int error_code;"
> in mmu_translate() is unreachable code. Since this is only a declaration,
> this isn't actually a bug, but:
>   * it's a bear-trap for future changes, because if it was changed to
>     include an initialization 'int error_code = foo;' then the
>     initialization wouldn't actually happen (being dead code)
>   * it's against our coding style, which wants declarations to be
>     at the start of blocks
>   * it means that anybody reading the code has to go and look up
>     exactly what the C rules are for skipping over variable declarations
>     using a goto
> 
> Move the declaration to the top of the function.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   target/i386/tcg/sysemu/excp_helper.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>