8278885: Remove Windows ARM64 int8_t workaround in G1

Reviewed-by: erikj, tschatzl, mli

Author: aamarsh

doc/building.html

@@ -298,7 +298,7 @@ <h3 id="apple-xcode">Apple Xcode</h3>
 <p>It is advisable to keep an older version of Xcode for building the JDK when updating Xcode. This <a href="http://iosdevelopertips.com/xcode/install-multiple-versions-of-xcode.html">blog page</a> has good suggestions on managing multiple Xcode versions. To use a specific version of Xcode, use <code>xcode-select -s</code> before running <code>configure</code>, or use <code>--with-toolchain-path</code> to point to the version of Xcode to use, e.g. <code>configure --with-toolchain-path=/Applications/Xcode8.app/Contents/Developer/usr/bin</code></p>
 <p>If you have recently (inadvertently) updated your OS and/or Xcode version, and the JDK can no longer be built, please see the section on <a href="#problems-with-the-build-environment">Problems with the Build Environment</a>, and <a href="#getting-help">Getting Help</a> to find out if there are any recent, non-merged patches available for this update.</p>
 <h3 id="microsoft-visual-studio">Microsoft Visual Studio</h3>
-<p>The minimum accepted version of Visual Studio is 2017. Older versions will not be accepted by <code>configure</code> and will not work. The maximum accepted version of Visual Studio is 2019.</p>
+<p>For aarch64 machines running Windows the minimum accepted version is Visual Studio 2019 (16.8 or higher). For all other platforms the minimum accepted version of Visual Studio is 2017.  Older versions will not be accepted by <code>configure</code> and will not work. For all platforms the maximum accepted version of Visual Studio is 2022.</p>
 <p>If you have multiple versions of Visual Studio installed, <code>configure</code> will by default pick the latest. You can request a specific version to be used by setting <code>--with-toolchain-version</code>, e.g. <code>--with-toolchain-version=2017</code>.</p>
 <p>If you have Visual Studio installed but <code>configure</code> fails to detect it, it may be because of <a href="#spaces-in-path">spaces in path</a>.</p>
 <h3 id="ibm-xl-cc">IBM XL C/C++</h3>

doc/building.md

@@ -374,9 +374,10 @@ available for this update.
 
 ### Microsoft Visual Studio
 
-The minimum accepted version of Visual Studio is 2017. Older versions will not
-be accepted by `configure` and will not work. The maximum accepted
-version of Visual Studio is 2019.
+For aarch64 machines running Windows the minimum accepted version is Visual Studio 2019 
+(16.8 or higher). For all other platforms the minimum accepted version of 
+Visual Studio is 2017. Older versions will not be accepted by `configure` and will 
+not work. For all platforms the maximum accepted version of Visual Studio is 2022.
 
 If you have multiple versions of Visual Studio installed, `configure` will by
 default pick the latest. You can request a specific version to be used by

make/autoconf/toolchain_microsoft.m4

@@ -103,6 +103,7 @@ AC_DEFUN([TOOLCHAIN_CHECK_POSSIBLE_VISUAL_STUDIO_ROOT],
             vc/auxiliary/build/vcvarsx86_amd64.bat vc/auxiliary/build/vcvars64.bat"
       elif test "x$TARGET_CPU" = xaarch64; then
         # for host x86-64, target aarch64
+        # aarch64 requires Visual Studio 16.8 or higher
         VCVARSFILES="vc/auxiliary/build/vcvarsamd64_arm64.bat \
             vc/auxiliary/build/vcvarsx86_arm64.bat"
       fi

src/hotspot/share/gc/g1/g1HeapRegionAttr.hpp

@@ -32,13 +32,7 @@
 // lookups for that information all over the place.
 struct G1HeapRegionAttr {
 public:
-#if defined(_M_ARM64)&& defined(_MSC_VER) && _MSC_VER <= 1927
-  // workaround for MSCV ARM64 bug
-  // https://developercommunity.visualstudio.com/content/problem/1079221/arm64-bad-code-generation-around-signed-char-arith.html
-  typedef int32_t region_type_t;
-#else
   typedef int8_t region_type_t;
-#endif
   // remset_is_tracked_t is essentially bool, but we need precise control
   // on the size, and sizeof(bool) is implementation specific.
   typedef uint8_t remset_is_tracked_t;