jdk8-mips64-public/hotspot: changeset 3:ef5b28e8d433

TemplateTable::fast_xaccess(): fix unaligned lhu

BCP and offset may both be unaligned.
Two LBU are required.

public class List {
public List next;

public void insert() {
List p = new List();
p.next = this.next;
}

public static void main(String[] args) throws Exception {
List th = new List();
while(true)
th.insert();
}
}

Effect:
- -Xint: 0 unaligned access

     1.1 --- a/src/cpu/mips/vm/assembler_mips.cpp	Thu May 05 14:53:07 2016 -0400
     1.2 +++ b/src/cpu/mips/vm/assembler_mips.cpp	Thu May 05 17:04:35 2016 -0400
     1.3 @@ -3277,22 +3277,17 @@
     1.4  
     1.5  void MacroAssembler::load_two_bytes_from_at_bcp(Register reg, Register tmp, int offset)
     1.6  {
     1.7 -
     1.8 -  if(offset & 1){
     1.9 -    lbu(reg, BCP, offset+1); 
    1.10 -    lbu(tmp, BCP, offset);
    1.11 +  /* 2016/5/6 Jin: the runtime address of BCP may be unaligned.
    1.12 +   *   Refer to the SPARC implementation. */
    1.13 +  lbu(reg, BCP, offset+1); 
    1.14 +  lbu(tmp, BCP, offset);
    1.15  #ifdef _LP64
    1.16 -//FIXME aoqi. indexbyte1 << 8 | indexbyte2?
    1.17 -    //dsll(tmp, tmp, 8);
    1.18 -    dsll(reg, reg, 8);
    1.19 -    daddu(reg, tmp, reg);
    1.20 +  dsll(reg, reg, 8);
    1.21 +  daddu(reg, tmp, reg);
    1.22  #else
    1.23 -    sll(reg, reg, 8);
    1.24 -    addu(reg, tmp, reg);
    1.25 +  sll(reg, reg, 8);
    1.26 +  addu(reg, tmp, reg);
    1.27  #endif
    1.28 -  }
    1.29 -  else
    1.30 -    lhu(reg, BCP, offset);
    1.31  }
    1.32  
    1.33  void MacroAssembler::store_two_byts_to_at_bcp(Register reg, Register tmp, int offset)

Mercurial > jdk8-mips64-public > hotspot / changeset

changeset

TemplateTable::fast_xaccess(): fix unaligned lhu