[aarch64-port-dev ] RFR: heapbase register can be allocated in compressed mode

[Kuai Wei]

Hi Andrew,

  Could you tell more detail about it? I can start a new patch for it if it break anything.

Kuai Wei


------------------------------------------------------------------
From:Andrew Haley <aph at redhat.com>
Send Time:2020年4月20日(星期一) 18:01
To:Pengfei Li <Pengfei.Li at arm.com>; 蒯微(麦庶) <kuaiwei.kw at alibaba-inc.com>; "Liu, Xin" <xxinliu at amazon.com>; hotspot compiler <hotspot-compiler-dev at openjdk.java.net>
Cc:nd <nd at arm.com>; aarch64-port-dev at openjdk.java.net <aarch64-port-dev at openjdk.java.net>
Subject:Re: RFR: heapbase register can be allocated in compressed mode

On 4/20/20 9:48 AM, Andrew Haley wrote:
> On 4/20/20 5:32 AM, Pengfei Li wrote:
>> Maybe Andrew Haley or other AArch64 reviewers can help?
>>
>> [1] http://cr.openjdk.java.net/~wzhuo/8242449/webrev.01/
> It's fine.

Sorry, no it isn't fine. Please get rid of this hunk:

--- old/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp 2020-04-14 21:18:52.009758661 +0800
+++ new/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp 2020-04-14 21:18:51.785764043 +0800
@@ -2185,6 +2185,10 @@
 #if 0
   assert (UseCompressedOops || UseCompressedClassPointers, "should be compressed");
   assert (Universe::heap() != NULL, "java heap should be initialized");
+  if (!UseCompressedOops || Universe::ptr_base() == NULL) {
+    // rheapbase is allocated as general register
+    return;
+  }
   if (CheckCompressedOops) {
     Label ok;
     push(1 << rscratch1->encoding(), sp); // cmpptr trashes rscratch1

-- 
Andrew Haley  (he/him)
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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