[PATCH resend] 8152856: Use (~0u) instead of (-1) when left-shifting

[Gerard Ziemski]

hi Alex,

Thank you for the patch.

I know it’s a bit of a hassle, but could you please file a new issue to cover your proposed fix and why you want it in?


cheers

> On May 24, 2016, at 1:27 PM, Alex Henrie <alexhenrie24 at gmail.com> wrote:
> 
> # HG changeset patch
> # User ahenrie
> # Date 1463507859 21600
> #      Tue May 17 11:57:39 2016 -0600
> # Node ID b7b02a758a39c9dab702c3b14c773fd601951384
> # Parent  d2e2a5306fed8dd9bce3d81e8fe15cf465eabb05
> 8152856: Use (~0u) instead of (-1) when left-shifting
> 
> diff --git a/src/share/vm/code/dependencies.hpp b/src/share/vm/code/dependencies.hpp
> --- a/src/share/vm/code/dependencies.hpp
> +++ b/src/share/vm/code/dependencies.hpp
> @@ -163,17 +163,17 @@ class Dependencies: public ResourceObj {
>     call_site_target_value,
> 
>     TYPE_LIMIT
>   };
>   enum {
>     LG2_TYPE_LIMIT = 4,  // assert(TYPE_LIMIT <= (1<<LG2_TYPE_LIMIT))
> 
>     // handy categorizations of dependency types:
> -    all_types           = ((1 << TYPE_LIMIT) - 1) & ((-1) << FIRST_TYPE),
> +    all_types           = ((1 << TYPE_LIMIT) - 1) & ((~0u) << FIRST_TYPE),
> 
>     non_klass_types     = (1 << call_site_target_value),
>     klass_types         = all_types & ~non_klass_types,
> 
>     non_ctxk_types      = (1 << evol_method) | (1 << call_site_target_value),
>     implicit_ctxk_types = 0,
>     explicit_ctxk_types = all_types & ~(non_ctxk_types | implicit_ctxk_types),
> 
> diff --git a/src/share/vm/oops/cpCache.hpp b/src/share/vm/oops/cpCache.hpp
> --- a/src/share/vm/oops/cpCache.hpp
> +++ b/src/share/vm/oops/cpCache.hpp
> @@ -188,17 +188,17 @@ class ConstantPoolCacheEntry VALUE_OBJ_C
>     is_final_shift             = 22,  // (f) is the field or method final?
>     is_volatile_shift          = 21,  // (v) is the field volatile?
>     is_vfinal_shift            = 20,  // (vf) did the call resolve to a final method?
>     // low order bits give field index (for FieldInfo) or method parameter size:
>     field_index_bits           = 16,
>     field_index_mask           = right_n_bits(field_index_bits),
>     parameter_size_bits        = 8,  // subset of field_index_mask, range is 0..255
>     parameter_size_mask        = right_n_bits(parameter_size_bits),
> -    option_bits_mask           = ~(((-1) << tos_state_shift) | (field_index_mask | parameter_size_mask))
> +    option_bits_mask           = ~(((~0u) << tos_state_shift) | (field_index_mask | parameter_size_mask))
>   };
> 
>   // specific bit definitions for the indices field:
>   enum {
>     cp_index_bits              = 2*BitsPerByte,
>     cp_index_mask              = right_n_bits(cp_index_bits),
>     bytecode_1_shift           = cp_index_bits,
>     bytecode_1_mask            = right_n_bits(BitsPerByte), // == (u1)0xFF