PPC/s390: [turbofan] Support variable size argument removal in TF-generated functions

PPC/s390: [turbofan] Support variable size argument removal in TF-generated functions

Port 5319b50c853c4213d825aa7cf620fde5d827f7eb

Original commit message:

    This is preparation for using TF to create builtins that handle variable number of
    arguments and have to remove these arguments dynamically from the stack upon
    return.

    The gist of the changes:
    - Added a second argument to the Return node which specifies the number of stack
      slots to pop upon return in addition to those specified by the Linkage of the
      compiled function.
    - Removed Tail -> Non-Tail fallback in the instruction selector. Since TF now should
      handles all tail-call cases except where the return value type differs, this fallback
      was not really useful and in fact caused unexpected behavior with variable
      sized argument popping, since it wasn't possible to materialize a Return node
      with the right pop count from the TailCall without additional context.
    - Modified existing Return generation to pass a constant zero as the additional
      pop argument since the variable pop functionality

R=danno@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Committed: https://crrev.com/2c846a2ac7dd93f18f453a1178abca414b4155cf
Cr-Commit-Position: refs/heads/master@{#40682}

[JaideepBajwa, 2016-10-31 19:30:36]

PTAL

[john.yan, 2016-10-31 19:32:06]

lgtm

[JaideepBajwa, 2016-10-31 19:32:41]

The CQ bit was checked by bjaideep@ca.ibm.com

[commit-bot: I haz the power, 2016-10-31 19:32:44]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-31 20:00:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-17 22:18:35]

Description was changed from

==========
PPC/s390: [turbofan] Support variable size argument removal in TF-generated
functions

Port 5319b50c853c4213d825aa7cf620fde5d827f7eb

Original commit message:

    This is preparation for using TF to create builtins that handle variable
number of
    arguments and have to remove these arguments dynamically from the stack upon
    return.

    The gist of the changes:
    - Added a second argument to the Return node which specifies the number of
stack
      slots to pop upon return in addition to those specified by the Linkage of
the
      compiled function.
    - Removed Tail -> Non-Tail fallback in the instruction selector. Since TF
now should
      handles all tail-call cases except where the return value type differs,
this fallback
      was not really useful and in fact caused unexpected behavior with variable
      sized argument popping, since it wasn't possible to materialize a Return
node
      with the right pop count from the TailCall without additional context.
    - Modified existing Return generation to pass a constant zero as the
additional
      pop argument since the variable pop functionality

R=danno@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com,
michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N
==========

to

==========
PPC/s390: [turbofan] Support variable size argument removal in TF-generated
functions

Port 5319b50c853c4213d825aa7cf620fde5d827f7eb

Original commit message:

    This is preparation for using TF to create builtins that handle variable
number of
    arguments and have to remove these arguments dynamically from the stack upon
    return.

    The gist of the changes:
    - Added a second argument to the Return node which specifies the number of
stack
      slots to pop upon return in addition to those specified by the Linkage of
the
      compiled function.
    - Removed Tail -> Non-Tail fallback in the instruction selector. Since TF
now should
      handles all tail-call cases except where the return value type differs,
this fallback
      was not really useful and in fact caused unexpected behavior with variable
      sized argument popping, since it wasn't possible to materialize a Return
node
      with the right pop count from the TailCall without additional context.
    - Modified existing Return generation to pass a constant zero as the
additional
      pop argument since the variable pop functionality

R=danno@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com,
michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Committed: https://crrev.com/2c846a2ac7dd93f18f453a1178abca414b4155cf
Cr-Commit-Position: refs/heads/master@{#40682}
==========

[commit-bot: I haz the power, 2016-11-17 22:18:35]

Patchset 1 (id:??) landed as
https://crrev.com/2c846a2ac7dd93f18f453a1178abca414b4155cf
Cr-Commit-Position: refs/heads/master@{#40682}