[wasm] Enable wasm relinking by default for Release config

[radical]

Set default value for $(WasmBuildNative) based on:

• If $(WasmBuildNative) is already set (eg. by user project) to true, then error if EMSDK_PATH is unset

• if unset, and$(PublishTrimmed) == false, then set to false

• if unset, and $(Configuration) == "Release", then set to true

• If it is $(WasmBuildNative) == true after above steps, and emsdk is missing
  => then emit a warning, and set it to false

Fixes: #48349

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Issue Details

---

Fixes: #48349

Author:	radical
Assignees:	-
Labels:	arch-wasm, area-Build-mono
Milestone:	-

[radical]

Test can be added once #47683 is merged.

[lewing]

A couple of thoughts.

• There is little reason to run this step if PublishTrimmed isn't true.
• If EMSDK isn't installed
  • Error in anything other than interpreter only mode
  • Warning in interpreter mode
  • Error in a couple of other cases

[vargaz]

Also, native linking is very slow, so making it the default will hurt user experience.

[lewing]

yes, In interpreter mode we don't require it unless the default icall/pinvoke tables are missing symbols (extra symbols are fine) and that will only happen if we've added references to native assets in which case we'll need to relink to include them and add to the tables. And ideally we we only do that if the native assets change.

[marek-safar]

I don't think there is much concern for the release/deploy configuration to be slow because it runs more optimizations.

[radical]

• There is little reason to run this step if PublishTrimmed isn't true.
  👍

• If EMSDK isn't installed

  • Error in anything other than interpreter only mode
  • Warning in interpreter mode

What do you mean by "interpreter mode"? $(AOTMode)?

• Error in a couple of other cases

Could you enumerate those, or at least the ones that we definitely want in this PR?

[lewing]

Needs to be false by default if emsdk is not present

[radical]

Needs to be false by default if emsdk is not present

1. If $(WasmBuildNative) is already set to true, then error if no emsdk?
2. If not set at all, and we want to set it to true based on other conditions
   => then set to false if emsdk is not present, and a warning?

Something like this? I'm guessing that we would want to avoid silently skipping relinking, because EMSDK_PATH wasn't set, but maybe was expected.

[lewing]

yes

[lewing]

The logic looks good and I'm ok with landing this as is to let packages flow to aspnetcore but let's not close #48349 yet. The messages need some work and we will need a follow up that abstracts the conditional logic in a slightly different way.

[radical]

The logic looks good and I'm ok with landing this as is to let packages flow to aspnetcore but let's not close #48349 yet. The messages need some work and we will need a follow up that abstracts the conditional logic in a slightly different way.

Yeah, the conditional logic will get simplified, but there are bunch of PRs in flight right now, after which it should be sorted out.

re:messages, yes!!

[trylek]

@radical - I think your change has broken the dotnet-linker-tests pipeline,

https://dev.azure.com/dnceng/public/_build?definitionId=861

All jobs after your check-in now show:

Job build_Browser_wasm_release_Runtime_Release depends on unknown job mono_browser_offsets.

Could you please take a look?

Cc @directhex who is still the test cop AFAIK, otherwise he'll forward as appropriate.

Cc @dotnet/runtime-infrastructure

[radical]

@trylek working on a fix now, in #49774