[aarch64-port-dev ] RFR/RFC 8219011: Implement MacroAssembler::warn method on AArch64

[Aleksey Shipilev]

RFE:
  https://bugs.openjdk.java.net/browse/JDK-8219011

It seems odd to keep MacroAssembler::warn declared, but not defined. We have rectified this in every
release, except 8u-aarch64. We can instead remove MacroAssembler::warn declaration, but that would
deviate from both 8u upstream and every other release too. This is 8u-aarch64 backport for
aarch64-port/jdk8u-shenandoah:

diff -r eaf9b36b7a30 src/cpu/aarch64/vm/macroAssembler_aarch64.cpp
--- a/src/cpu/aarch64/vm/macroAssembler_aarch64.cpp     Tue Aug 06 10:45:43 2019 +0200
+++ b/src/cpu/aarch64/vm/macroAssembler_aarch64.cpp     Wed Aug 07 14:57:04 2019 +0200
@@ -2009,4 +2009,12 @@
 }

+void MacroAssembler::warn(const char* msg) {
+  pusha();
+  mov(c_rarg0, (address)msg);
+  mov(lr, CAST_FROM_FN_PTR(address, warning));
+  blr(lr);
+  popa();
+}
+
 // If a constant does not fit in an immediate field, generate some
 // number of MOV instructions and then perform the operation.

Testing: aarch64 build

-- 
Thanks,
-Aleksey