haowei added a comment. In D144603#4162048 <https://reviews.llvm.org/D144603#4162048>, @smeenai wrote:
> Hmm, what cache key does ccache use for compilers? Is it the `--version` > output string, the path, or some combination? If the path is involved then I > don't see any value in using ccache for configuring anything past stage1, > since the compiler will (presumably) be installed somewhere else afterwards > and not used directly from the build tree. If it's just `--version`, what are > the cache pollution concerns? The compiler binaries output by all the stages > should produce the same outputs given the same inputs (and presumably have > the same `--version`), right? I am not sure about ccache. We use an internal distributed build cache system when we build LLVM. The compiler binary hash and the `--version` output will both be used to calculate the cache key so there is little value to use caching past stage1 as the runtime build and stage2+ will be built from a fresh from source compiler and it will always result in cache miss. I don't believe ccache only uses `--version` output as cache key since two compiler binary with the same version string can have different output (e.g. 2 WIP source tree but track the same git revision). So think it would be beneficial to add a flag to avoid using compiler launcher past stage1. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D144603/new/ https://reviews.llvm.org/D144603 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
