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When using cargo this was already effectively done for all dependencies as cargo passes -Clinker-plugin-lto without -Clto=fat/thin. -Clinker-plugin-lto assumes that ThinLTO will be used. The ThinLTO pre-link pipeline is faster than the fat LTO one. And according to the benchmarks in [1] there is barely any runtime performance difference between executables that used fat LTO with the fat vs ThinLTO pre-link pipeline. [1]: https://discourse.llvm.org/t/rfc-a-unified-lto-bitcode-frontend/61774
This reverts commit 30d7ed4. It should not be needed any more.
[win] Fix truncated unwinds for Arm64 Windows Panic backtraces on ARM64 Windows are truncated because Rust's LLVM configuration sets `NoTrapAfterNoreturn = true`, which suppresses the generation of `brk #0x1` (trap) instructions after calls to `noreturn` functions. Without this trap instruction, the return address from a `noreturn` call points past the end of the calling function into an unrelated function, causing `RtlLookupFunctionEntry` to return the wrong unwind information, which terminates the stack walk prematurely. In general, `NoTrapAfterNoreturn = true` is recommended against for Windows, since we have seen security vulnerabilities in the past where an attacker has managed to return from a noreturn function, or the function wasn't actually noereturn, resulting in executing whatever was after the call. This change disables setting `NoTrapAfterNoreturn = true` for Windows. Fixes rust-lang#140489
…cuviper coretest in miri: fix using unstable libtest features Alternative (IMO preferable) to rust-lang#153369. Also reverts that PR.
…viper Always use the ThinLTO pipeline for pre-link optimizations When using cargo this was already effectively done for all dependencies as cargo passes -Clinker-plugin-lto without -Clto=fat/thin. -Clinker-plugin-lto assumes that ThinLTO will be used. The ThinLTO pre-link pipeline is faster than the fat LTO one. And according to the benchmarks in [^1] there is barely any runtime performance difference between executables that used fat LTO with the fat vs ThinLTO pre-link pipeline. This also helps avoid having yet another code path if we want to support Unified LTO (that is a single bitcode file that supports being used for both fat LTO and ThinLTO when using linker plugin LTO, we already support it when rustc does LTO as ThinLTO bitcode is enough of a superset of fat LTO bitcode that it happens to work by accident if you don't explicitly have a check preventing mixing of them for the current set of LTO features that rustc exposes.) I'm currently still investigating if rustc would benefit from Unified LTO and how exactly to integrate it. [^1]: https://discourse.llvm.org/t/rfc-a-unified-lto-bitcode-frontend/61774
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@bors r+ rollup=never p=5 |
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Yielding to a slightly newer/larger rollup: |
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