Added compilation failure if a max ubo size is exceeded

[gaaclarke]

issue: #163580

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• I followed the breaking change policy and added Data Driven Fixes where supported.
• All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel on Discord.

[flutter-dashboard]

It looks like this pull request may not have tests. Please make sure to add tests before merging. If you need an exemption, contact "@test-exemption-reviewer" in the #hackers channel in Discord (don't just cc them here, they won't see it!).

If you are not sure if you need tests, consider this rule of thumb: the purpose of a test is to make sure someone doesn't accidentally revert the fix. Ask yourself, is there anything in your PR that you feel it is important we not accidentally revert back to how it was before your fix?

Reviewers: Read the Tree Hygiene page and make sure this patch meets those guidelines before LGTMing. The test exemption team is a small volunteer group, so all reviewers should feel empowered to ask for tests, without delegating that responsibility entirely to the test exemption group.

[gaaclarke]

The theory is that this isn't sufficient, but this is the max size right now and it's used by conical_gradient_uniform_fill.frag

[jonahwilliams]

Seems like a good idea.

I thought that the shaderc limits would help us?

flutter/engine/src/flutter/impeller/compiler/spirv_compiler.cc

Line 92 in a4a5a33

static void SetDefaultLimitations(shaderc::CompileOptions& compiler_opts) {

are we not setting these to the right values? or is it not hooked up correctly?

[gaaclarke]

are we not setting these to the right values? or is it not hooked up correctly?

Yea, I looked into those. I'm pretty sure they don't have one that does what we need, they aren't exactly documented. The closest thing they have is shaderc_limit_max_fragment_uniform_components. It doesn't seem to use the calculated size of the items to figure out if the offset will overflow. The only place I could find that is in the spirv_cross compiler.

Also, I found this: https://docs.qualcomm.com/bundle/publicresource/topics/80-78185-2/best_practices.html?product=1601111740035277#buffer-best-practices

It says the sum of the ubos should be <= 7372 bytes. We should be good. Based on what Jason is telling me I don't think dropping this is going to fix our issue.

[jonahwilliams]

LGTM

[auto-submit]

autosubmit label was removed for flutter/flutter/164038, because - The status or check suite Windows windows_unopt has failed. Please fix the issues identified (or deflake) before re-applying this label.

• The status or check suite Windows windows_arm_host_engine has failed. Please fix the issues identified (or deflake) before re-applying this label.