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authorNicholas Nethercote <n.nethercote@gmail.com>2023-07-21 08:58:08 +1000
committerNicholas Nethercote <n.nethercote@gmail.com>2023-07-31 16:21:02 +1000
commit0ea9950ede4dd5257776b126361c93f28b556eec (patch)
tree0dd8eb5445b984a6569700197fe47fb4d9c7c991
parent67e4bec200d9e0b208af9bdfd917bc05dec31831 (diff)
Document `-Zno-parallel-llvm`.
Because it's usefulness wasn't clear to me, and I initially wondered if
it could be removed. The text is based on the text in #50972, the PR
that added the flag.
-rw-r--r--src/doc/unstable-book/src/compiler-flags/no-parallel-llvm.md8
1 files changed, 8 insertions, 0 deletions
diff --git a/src/doc/unstable-book/src/compiler-flags/no-parallel-llvm.md b/src/doc/unstable-book/src/compiler-flags/no-parallel-llvm.md
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+++ b/src/doc/unstable-book/src/compiler-flags/no-parallel-llvm.md
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+# `no-parallel-llvm`
+
+---------------------
+
+This flag disables parallelization of codegen and linking, while otherwise preserving
+behavior with regard to codegen units and LTO.
+
+This flag is not useful for regular users, but it can be useful for debugging the backend. Codegen issues commonly only manifest under specific circumstances, e.g. if multiple codegen units are used and ThinLTO is enabled. Serialization of these threaded configurations makes the use of LLVM debugging facilities easier, by avoiding the interleaving of output.