IssueTracker

I believe https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/5346490 should make this work, though I also noticed that we're not passing any form of --jobs to x.py, so RBE's "more parallelism" benefit doesn't really exist as it stands.

On the other hand, passing --jobs=$(get_makeopts_jobs) applies that limit to both Rust's and LLVM's builds. cargo -j1000 isn't being a good citizen on machines that are also running make -j$(ncpu).

Maybe there's room for a local patch, and/or advocating upstream for --llvm-jobs, depending on whether reclient can be made to work with the rustc invocations here.

Hrmm,

FAILED: lib/Demangle/CMakeFiles/LLVMDemangle.dir/MicrosoftDemangle.cpp.o 
/var/tmp/portage/dev-lang/rust-host-1.75.0-r1/files/reclient_compiler_launcher.sh /usr/bin/x86_64-pc-linux-gnu-clang++ -DGTEST_HAS_RTTI=0 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/var/tmp/portage/dev-lang/rust-host-1.75.0-r1/work/build/x86_64-pc-linux-gnu/llvm/build/lib/Demangle -I/var/tmp/portage/dev-lang/rust-host-1.75.0-r1/work/rustc-1.75.0-src/src/llvm-project/llvm/lib/Demangle -I/var/tmp/portage/dev-lang/rust-host-1.75.0-r1/work/build/x86_64-pc-linux-gnu/llvm/build/include -I/var/tmp/portage/dev-lang/rust-host-1.75.0-r1/work/rustc-1.75.0-src/src/llvm-project/llvm/include -ffunction-sections -fdata-sections -fPIC --target=x86_64-pc-linux-gnu -pipe -fprofile-use=/var/tmp/portage/dev-lang/rust-host-1.75.0-r1/work/rust-pgo-1.75.0-llvm.profdata -fvisibility-inlines-hidden -w -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Demangle/CMakeFiles/LLVMDemangle.dir/MicrosoftDemangle.cpp.o -MF lib/Demangle/CMakeFiles/LLVMDemangle.dir/MicrosoftDemangle.cpp.o.d -o lib/Demangle/CMakeFiles/LLVMDemangle.dir/MicrosoftDemangle.cpp.o -c /var/tmp/portage/dev-lang/rust-host-1.75.0-r1/work/rustc-1.75.0-src/src/llvm-project/llvm/lib/Demangle/MicrosoftDemangle.cpp
F0306 00:48:52.636827    8376 main.go:174] Command failed: rpc error: code = Internal desc = /mnt/host/source/src/chromium/depot_tools/.cipd_bin/reclient/scandeps_server terminated during startup: %!w(*command.Result=&{127 3 <nil>})
[2/2503] Building CXX object lib/Demangle/CMakeFiles/LLVMDemangle.dir/MicrosoftDemangleNodes.cpp.o
FAILED: lib/Demangle/CMakeFiles/LLVMDemangle.dir/MicrosoftDemangleNodes.cpp.o 

Looks like reclient didn't like something?

Do you have any of the reproxy logs? Looks like it might be a dependency scanner issue.