tree ed6f942487080ad19dbf86024f47ad322a88dadd
parent 306c1b46d6cc322a58affda0498abdecca4492d8
author Brian Osman <brianosman@google.com> 1660147241 +0000
committer SkCQ <skcq-be@skia-corp.google.com.iam.gserviceaccount.com> 1660147283 +0000

Revert "Guarantee that raster pipeline always uses finite stack"

This reverts commit 3809e9bd28ae110271dccb4e7eeacd2b76a0223b.

Reason for revert: FM-TSAN bot is unhappy

Original change's description:
> Guarantee that raster pipeline always uses finite stack
>
> In release builds, clang and gcc do tail call optimization, which
> reuses the same stack space for each stage. In debug builds, that
> doesn't happen. If we're going to start generating arbitrarily long
> pipelines (eg from SkSL), we need to ensure that we're not going to
> overflow the stack.
>
> I first looked at ways to force tail call optimization (Clang's
> musttail, and optimization pragmas). These are all nonportable, and
> don't work on some of our supported toolchains.
>
> Instead, this version includes a new RP execution mode that does away
> with the tail-calling entirely. Instead, each stage just returns the
> next stage to call. This ruins our optimized stage ABI, obviously, but
> we're only doing it in debug builds.
>
> MSVC can do tail call optimization, but testing shows that it falls over
> with raster pipeline (too complex?). As a result, we always use the new
> technique there.
>
> Our new unit test measures stack consumption (which is the thing we're
> worried about anyway) to make sure that TCO or our new technique is
> successfully limiting stack usage.
>
> Change-Id: Id0d419f97b53b0b57c82214c4a2f1f94e5ab6b3c
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/566896
> Reviewed-by: Herb Derby <herb@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>

Change-Id: Ic1802d307c919160618826ab7683c05cd448b16e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/567438
Auto-Submit: Brian Osman <brianosman@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>