8276799: Implementation of JEP 422: Linux/RISC-V Port

8283737: riscv: MacroAssembler::stop() should emit fixed-length instruction sequence
8285437: riscv: Fix MachNode size mismatch for MacroAssembler::verify_oops*
8287418: riscv: Fix correctness issue of MacroAssembler::movptr
8293100: RISC-V: Need to save and restore callee-saved FloatRegisters in StubGenerator::generate_call_stub
8295926: RISC-V: C1: Fix LIRGenerator::do_LibmIntrinsic
8291952: riscv: Remove PRAGMA_NONNULL_IGNORED
8308277: RISC-V: Improve vectorization of Match.sqrt() on floats
8282306: os::is_first_C_frame(frame*) crashes on invalid link access

Co-authored-by: Xiaolin Zheng <xlinzheng@openjdk.org>
Reviewed-by: fyang
Backport-of: 5905b02c0e2643ae8d097562f181953f6c88fc89

Author: 2 people

make/autoconf/hotspot.m4

@@ -370,7 +370,8 @@ AC_DEFUN_ONCE([HOTSPOT_SETUP_JVM_FEATURES],
   AC_MSG_CHECKING([if shenandoah can be built])
   if HOTSPOT_CHECK_JVM_FEATURE(shenandoahgc); then
     if test "x$OPENJDK_TARGET_CPU_ARCH" = "xx86" || \
-       test "x$OPENJDK_TARGET_CPU" = "xaarch64"; then
+       test "x$OPENJDK_TARGET_CPU" = "xaarch64" || \
+       test "x$OPENJDK_TARGET_CPU" = "xriscv64"; then
       AC_MSG_RESULT([yes])
     else
       DISABLED_JVM_FEATURES="$DISABLED_JVM_FEATURES shenandoahgc"

make/autoconf/libraries.m4

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2011, 2022, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # This code is free software; you can redistribute it and/or modify it
@@ -130,6 +130,12 @@ AC_DEFUN_ONCE([LIB_SETUP_LIBRARIES],
     BASIC_JVM_LIBS="$BASIC_JVM_LIBS -lthread"
   fi
 
+  # Because RISC-V only has word-sized atomics, it requries libatomic where
+  # other common architectures do not.  So link libatomic by default.
+  if test "x$OPENJDK_TARGET_OS" = xlinux && test "x$OPENJDK_TARGET_CPU" = xriscv64; then
+    BASIC_JVM_LIBS="$BASIC_JVM_LIBS -latomic"
+  fi
+
   # perfstat lib
   if test "x$OPENJDK_TARGET_OS" = xaix; then
     BASIC_JVM_LIBS="$BASIC_JVM_LIBS -lperfstat"