[clang] [lld] [llvm] Integrated Distributed ThinLTO (DTLTO): Initial support (PR #126654)

[Tobias Hieta via cfe-commits]

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@@ -116,7 +117,18 @@ BitcodeCompiler::BitcodeCompiler(COFFLinkerContext &c) : ctx(c) {
 
   // Initialize ltoObj.
   lto::ThinBackend backend;
-  if (ctx.config.thinLTOIndexOnly) {
+  if (!ctx.config.DTLTODistributor.empty()) {
+    StringRef version = getenv("LLD_VERSION"); // For testing only.
+    if (version.empty())
+      version = ctx.saver.save(getLLDVersion());
+    backend = lto::createOutOfProcessThinBackend(
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tru wrote:

When I read this code at first I was confused why it needed to have the arguments for the parallelization, I looked at the comment in LTO.h later and realized that the arguments where not used for the actual codegen, but for generating the index. But I wonder if we even need to pass that as an argument then - it reads to me like it's controlling the external process in some way.

https://github.com/llvm/llvm-project/pull/126654