S390: [turbofan] CodeGenerator: Frame setup refactoring

S390: [turbofan] CodeGenerator: Frame setup refactoring

Port 81a1530e6fb3f4382098f71c01ffe047ffd72afc

Original commit message:

    Before frame elision, we finalized the frame shape when assembling the
    prologue, which is also when we prepared the frame (saving sp, etc).

    The frame finalization only needs to happen once, and happens to be
    actually a set of idempotent operations. With frame elision, the logic for
    frame finalization was happening every time we constructed the frame.
    Albeit idempotent operations, the code would become hard to maintain.

    This change separates frame shape finalization from frame
    construction. When constructing the CodeGenerator, we finalize the
    frame. Subsequent access is to a const Frame*.

    Also renamed AssemblePrologue to AssembleConstructFrame, as
    suggested in the frame elision CR.

    Separating frame setup gave the opportunity to do away with
    architecture-independent frame aligning (which is something just arm64
    cares about), and also with stack pointer setup (also arm64). Both of
    these happen now at frame finalization on arm64.

R=mtrofin@chromium.org, joransiu@ca.ibm.com, bjaideep@ca.ibm.com, michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Committed: https://crrev.com/2f2b3040b577a678ae2cbac79ed976a7c6a2e6aa
Cr-Commit-Position: refs/heads/master@{#35677}

[JoranSiu, 2016-04-20 20:06:31]

lgtm

[john.yan, 2016-04-20 20:10:38]

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

[commit-bot: I haz the power, 2016-04-20 20:10:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1903403002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1903403002/1

[commit-bot: I haz the power, 2016-04-20 20:37:59]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-22 19:13:48]

Description was changed from

==========
S390: [turbofan] CodeGenerator: Frame setup refactoring

Port 81a1530e6fb3f4382098f71c01ffe047ffd72afc

Original commit message:

    Before frame elision, we finalized the frame shape when assembling the
    prologue, which is also when we prepared the frame (saving sp, etc).

    The frame finalization only needs to happen once, and happens to be
    actually a set of idempotent operations. With frame elision, the logic for
    frame finalization was happening every time we constructed the frame.
    Albeit idempotent operations, the code would become hard to maintain.

    This change separates frame shape finalization from frame
    construction. When constructing the CodeGenerator, we finalize the
    frame. Subsequent access is to a const Frame*.

    Also renamed AssemblePrologue to AssembleConstructFrame, as
    suggested in the frame elision CR.

    Separating frame setup gave the opportunity to do away with
    architecture-independent frame aligning (which is something just arm64
    cares about), and also with stack pointer setup (also arm64). Both of
    these happen now at frame finalization on arm64.

R=mtrofin@chromium.org, joransiu@ca.ibm.com, bjaideep@ca.ibm.com,
michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

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

to

==========
S390: [turbofan] CodeGenerator: Frame setup refactoring

Port 81a1530e6fb3f4382098f71c01ffe047ffd72afc

Original commit message:

    Before frame elision, we finalized the frame shape when assembling the
    prologue, which is also when we prepared the frame (saving sp, etc).

    The frame finalization only needs to happen once, and happens to be
    actually a set of idempotent operations. With frame elision, the logic for
    frame finalization was happening every time we constructed the frame.
    Albeit idempotent operations, the code would become hard to maintain.

    This change separates frame shape finalization from frame
    construction. When constructing the CodeGenerator, we finalize the
    frame. Subsequent access is to a const Frame*.

    Also renamed AssemblePrologue to AssembleConstructFrame, as
    suggested in the frame elision CR.

    Separating frame setup gave the opportunity to do away with
    architecture-independent frame aligning (which is something just arm64
    cares about), and also with stack pointer setup (also arm64). Both of
    these happen now at frame finalization on arm64.

R=mtrofin@chromium.org, joransiu@ca.ibm.com, bjaideep@ca.ibm.com,
michael_dawson@ca.ibm.com, mbrandy@us.ibm.com

BUG=
LOG=N

Committed: https://crrev.com/2f2b3040b577a678ae2cbac79ed976a7c6a2e6aa
Cr-Commit-Position: refs/heads/master@{#35677}
==========

[commit-bot: I haz the power, 2016-04-22 19:13:49]

Patchset 1 (id:??) landed as
https://crrev.com/2f2b3040b577a678ae2cbac79ed976a7c6a2e6aa
Cr-Commit-Position: refs/heads/master@{#35677}