RFR: 8254072: AArch64: Get rid of --disable-warnings-as-errors on Windows+ARM64 build [v2]

[Bernhard Urban-Forster]

On Mon, 12 Oct 2020 10:29:23 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> Bernhard Urban-Forster has updated the pull request with a new target base due to a merge or a rebase. The pull request
>> now contains 18 commits:
>>  - Merge remote-tracking branch 'upstream/master' into 8254072-fix-windows-arm64-warnings
>>  - ./src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp(1441): warning C4267: 'argument': conversion from 'size_t' to
>>    'int', possible loss of data
>>    ./src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp(1446): warning C4267: 'argument': conversion from 'size_t' to
>>    'int', possible loss of data ./src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp(1654): warning C4267: 'argument':
>>    conversion from 'size_t' to 'int', possible loss of data
>>  - Revert changes for "warning C4146: unary minus operator applied to unsigned type, result still unsigned"
>>  - msvc: disable unary minus warning for unsigned types
>>  - ./src/hotspot/cpu/aarch64/templateInterpreterGenerator_aarch64.cpp(1123): warning C4267: 'initializing': conversion
>>    from 'size_t' to 'int', possible loss of data
>>    ./src/hotspot/cpu/aarch64/templateInterpreterGenerator_aarch64.cpp(1123): warning C4267: 'initializing': conversion
>>    from 'size_t' to 'const int', possible loss of data
>>  - ./src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp(1312): warning C4267: 'argument': conversion from 'size_t' to
>>    'unsigned int', possible loss of data
>>    ./src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp(1370): warning C4267: 'argument': conversion from 'size_t' to
>>    'int', possible loss of data ./src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp(1441): warning C4146: unary minus
>>    operator applied to unsigned type, result still unsigned ./src/hotspot/cpu/aarch64/stubGenerator_aarch64.cpp(1441):
>>    warning C4267: 'argument': conversion from 'size_t' to 'int', possible loss of data
>>  - ./src/hotspot/cpu/aarch64/sharedRuntime_aarch64.cpp(2472): warning C4312: 'type cast': conversion from 'unsigned int'
>>    to 'address' of greater size
>>  - ./src/hotspot/cpu/aarch64/sharedRuntime_aarch64.cpp(1527): warning C4267: 'argument': conversion from 'size_t' to
>>    'int', possible loss of data
>>  - ./src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp(2901): warning C4267: 'initializing': conversion from 'size_t' to
>>    'int', possible loss of data
>>    ./src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp(2901): warning C4267: 'initializing': conversion from 'size_t' to
>>    'const int', possible loss of data
>>  - ./src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp(2756): warning C4146: unary minus operator applied to unsigned
>>    type, result still unsigned
>>  - ... and 8 more: https://git.openjdk.java.net/jdk/compare/5351ba6c...a081dfb4
>
> Changes requested by ihse (Reviewer).

@theRealAph I prototyped changing the argument of `bang_stack_with_offset()` from `int` to `size_t` here:
https://github.com/lewurm/openjdk/commit/85a8f655aa0cb69ef13a2de44dd64c60caf19852. In that approach casting is
essentially pushed down to `bang_stack_with_offset` because the assembler instruction of most (all) architectures that
is eventually consuming that offset needs a signed integer anyway. Doesn't seem like a win to me to be honest.

I would rather prefer to go with what we have in this patch (similar to what x86 is doing today):
--- a/src/hotspot/cpu/aarch64/sharedRuntime_aarch64.cpp
+++ b/src/hotspot/cpu/aarch64/sharedRuntime_aarch64.cpp
@@ -1524,7 +1524,7 @@ nmethod* SharedRuntime::generate_native_wrapper(MacroAssembler* masm,

   // Generate stack overflow check
   if (UseStackBanging) {
-    __ bang_stack_with_offset(JavaThread::stack_shadow_zone_size());
+    __ bang_stack_with_offset((int)JavaThread::stack_shadow_zone_size());
   } else {
     Unimplemented();
   }
and leave it with that. What do you think?

-------------

PR: https://git.openjdk.java.net/jdk/pull/530