1602135 - Simplify build process for the wasi sysroot

Status: NEW

(Firefox Build System :: Toolchains, task)

Description

[Ricky Stewart]

As of bug 1596219 we're using the wasi-sdk github repo to construct the wasi-sysroot. The wasi-sdk repository is a pretty light wrapper around the llvm-project and wasi-libc repositories.

The build logic is encapsulated in the Makefile, which 1) builds a clang with wasm32-wasi as its default target, 2) builds the libc, 3) builds compiler-rt, 4) and builds libcxx/libcxxabi.

In principle since we already clone llvm-project and build clang and a bunch of the support libraries, we should be able to use our in-house clang to construct the sysroot from these sources ourselves. Doing so would require updating the wasi-sysroot toolchain definition to pull in those sources and writing a script that emulates the contents of the Makefile above. I attempted to do this and couldn't manage to pass the right set of command-line arguments to the build jobs to get things to work. The build errors that I ran into were all either compiler errors or really confounding linker errors that are not in my area of expertise. I'll attach a patch of the "latest version" of that attempt, which is still nonfunctional but somewhat close-ish probably a good place to start for anyone who wants to try to pick this work up.

Examples of some of the failures I encountered when trying to run various versions of this build in automation:

• This failure from this try push
• This failure from this try push

Comment 1

[Ricky Stewart]

Attachment: Bug 1602135 - Simplify build process for the wasi sysroot (DO NOT LAND, NOT FUNCTIONAL)

Comment 2

[Ricky Stewart]

See the attached revision (make sure to click "show abandoned revisions"). It doesn't work but could be a starting point for someone else wanting to pick this up.