You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@harmony.apache.org by "Aleksey Shipilev (JIRA)" <ji...@apache.org> on 2008/08/19 13:17:44 UTC
[jira] Commented: (HARMONY-5955) Jitrino does not reclaim some
unused memory units during the course of native code generation
[ https://issues.apache.org/jira/browse/HARMONY-5955?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12623637#action_12623637 ]
Aleksey Shipilev commented on HARMONY-5955:
-------------------------------------------
Hi,
Could you please generate the patch in unified format?
"diff -uwb" should be fine.
> Jitrino does not reclaim some unused memory units during the course of native code generation
> ---------------------------------------------------------------------------------------------
>
> Key: HARMONY-5955
> URL: https://issues.apache.org/jira/browse/HARMONY-5955
> Project: Harmony
> Issue Type: Improvement
> Components: DRLVM
> Affects Versions: 5.0M6
> Environment: Windows XP
> Reporter: Zhiguo Ge
> Priority: Minor
> Fix For: 5.0M6
>
> Attachments: patch.txt
>
>
> The CodeEmitter::emitCode( void ) function will generate native code from LIR without solving the target addresses of branch instructions. The codepack() function in Jitrino will resolve the target addresses and make native code smaller. As a result, less momory units are required for storing the native code after codepack() . However, Jitrino still allocates more than enough memory units for storing the native code.
> The following is an example of Java source code.
> static MapEntry successor(MapEntry x) {
> if (x.right != null)
> return minimum(x.right);
> MapEntry y = x.parent;
> while (y != null && x == y.right) {
> x = y;
> y = y.parent;
> }
> return y;
> }
> static MapEntry minimum(MapEntry x) {
> if(x.left != null)
> x = x.left;
> return x;
> }
> A portion of the output native code by codepack() function is as follows:
> 03B20337 nop
> 03B20338 xchg ax,ax
> 03B2033A call 0764035F
> 03B2033F add esp,4
> 03B20345 pop esi
> 03B20346 pop ebp
> 03B20347 pop ebx
> 03B20348 ret 0Ch
> 03B2034B add esp,4
> 03B20351 pop esi
> 03B20352 pop ebp
> 03B20353 pop ebx
> 03B20354 ret 0Ch
> 03B20357 add byte ptr [eax],al
> 03B20359 pop esi
> 03B2035A pop ebp
> 03B2035B pop ebx
> 03B2035C ret 0Ch
> 03B2035F add esp,4
> 03B20365 pop esi
> 03B20366 pop ebp
> 03B20367 pop ebx
> 03B20368 ret 0Ch
> The instructions from 03B20357 to 03B20368 are not used by any places while they still occupy memory entries.
> Our patch is to make Jitrino allocate exact demanded size of memory units for storing generated native code. Experiment result shows
> 3.4% memory requirement reduction for the example shown above.
>
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.