Apply some fixes to cross-language LTO (especially when targeting MSVC) #53031
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rust-highfive
added
the
S-waiting-on-review
|
@bors try |
bors
added a commit
that referenced
this pull request
Aug 3, 2018
Apply some fixes to cross-language LTO (especially when targeting MSVC) This PR contains a few fixes that were needed in order to get Firefox compiling with Rust/C++ cross-language ThinLTO on Windows. The commits are self-contained and should be self-explanatory. r? @alexcrichton
alexcrichton
reviewed
Aug 3, 2018
| @@ -1626,8 +1626,12 @@ fn relevant_lib(sess: &Session, lib: &NativeLibrary) -> bool { | |||
| fn is_full_lto_enabled(sess: &Session) -> bool { | |||
There was a problem hiding this comment.
With the comment below, perhaps this function could be renamed to something like are_upstream_rust_objects_already_included? (albeit a bit wordy)
There was a problem hiding this comment.
Sounds good to me.
| @@ -1331,6 +1335,11 @@ fn execute_work_item(cgcx: &CodegenContext, | |||
| let needs_lto = match cgcx.lto { | |||
| Lto::No => false, | |||
|
|
|||
| // If the linker does LTO, we don't have to do it. Note that we | |||
| // keep doing full LTO, if it is requested, as not to break the | |||
| // assumption that the output will be a single module. | |||
There was a problem hiding this comment.
To confirm, this is a rustc bug, right? This is fixable on our end where fat LTO plus cross-lang-lto shouldn't actually run the LTO passes in rustc?
There was a problem hiding this comment.
Yes, it probably isn't too hard to do just the module merging but not the optimizations. Maybe in another PR, unless you think it's urgent.
There was a problem hiding this comment.
Oh nah definitely fine to happen later, just wanted to make sure I understood!
| sess.opts.cg.prefer_dynamic && | ||
| sess.target.target.options.is_like_msvc { | ||
| sess.err("Linker plugin based LTO is not supported together with \ | ||
| `-C prefer-dynamic` when targeting MSVC"); |
There was a problem hiding this comment.
Could a comment be added above this with a brief explanation as to why the error is being emitted? AFAIK it's all b/c of DLL weirdness, right?
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
|
☀️ Test successful - status-travis |
|
@rust-timer build 807bbd9 |
|
Success: Queued 807bbd9 with parent 88e0ff1, comparison URL. |
|
Perf is ready. Almost nothing is changed. |
|
Hm, there's still a bit of a regression. It might be coming from allocating the |
michaelwoerister
force-pushed
the
cross-lto
branch
from
0b253da
to
603584d
Compare
michaelwoerister
added a commit
to michaelwoerister/rust
that referenced
this pull request
Aug 6, 2018
|
@bors try ( |
bors
added a commit
that referenced
this pull request
Aug 6, 2018
Apply some fixes to cross-language LTO (especially when targeting MSVC) This PR contains a few fixes that were needed in order to get Firefox compiling with Rust/C++ cross-language ThinLTO on Windows. The commits are self-contained and should be self-explanatory. r? @alexcrichton
kennytm
added
the
S-waiting-on-perf
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
|
💔 Test failed - status-travis |
bors
added
S-waiting-on-author
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
michaelwoerister
force-pushed
the
cross-lto
branch
from
603584d
to
551ef38
Compare
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
michaelwoerister
force-pushed
the
cross-lto
branch
from
551ef38
to
1ecb0a5
Compare
|
@bors try |
|
⌛ Trying commit 1ecb0a56fd1211e1357c59cedd22e94bef989596 with merge 63d3f70a598b20ea7e9eb775348456a015daedb5... |
|
💔 Test failed - status-travis |
bors
added
S-waiting-on-review
|
The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
|
|
Hm, everything passed except for |
bors
added
S-waiting-on-bors
bors
added a commit
that referenced
this pull request
Aug 9, 2018
Apply some fixes to cross-language LTO (especially when targeting MSVC) This PR contains a few fixes that were needed in order to get Firefox compiling with Rust/C++ cross-language ThinLTO on Windows. The commits are self-contained and should be self-explanatory. r? @alexcrichton
|
☀️ Test successful - status-appveyor, status-travis |
|
@michaelwoerister is there a guide somewhere explaining how to use Cross-Language LTO? I‘m Linking a vectorized version of libm in packed simd that gets compiled from C and would like it to be inlined into Rust. I’d also like to set this up for jemalloc. |
|
No guide yet. You basically:
Note that things are still experimental (although stable enough to build Firefox with it). |
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Aug 24, 2018
This fixes a regression from rust-lang#53031 where specifying `-C target-cpu=native` is printing a lot of warnings from LLVM about `native` being an unknown CPU. It turns out that `native` is indeed an unknown CPU and we have to perform a mapping to an actual CPU name, but this mapping is only performed in one location rather than all locations we inform LLVM about the target CPU. This commit centralizes the mapping of `native` to LLVM's value of the native CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's never `native`. Closes rust-lang#53322
bors
added a commit
that referenced
this pull request
Aug 27, 2018
Fix warnings about the `native` target-cpu This fixes a regression from #53031 where specifying `-C target-cpu=native` is printing a lot of warnings from LLVM about `native` being an unknown CPU. It turns out that `native` is indeed an unknown CPU and we have to perform a mapping to an actual CPU name, but this mapping is only performed in one location rather than all locations we inform LLVM about the target CPU. This commit centralizes the mapping of `native` to LLVM's value of the native CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's never `native`. Closes #53322
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Aug 27, 2018
This fixes a regression from rust-lang#53031 where specifying `-C target-cpu=native` is printing a lot of warnings from LLVM about `native` being an unknown CPU. It turns out that `native` is indeed an unknown CPU and we have to perform a mapping to an actual CPU name, but this mapping is only performed in one location rather than all locations we inform LLVM about the target CPU. This commit centralizes the mapping of `native` to LLVM's value of the native CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's never `native`. Closes rust-lang#53322
bors
added a commit
that referenced
this pull request
Aug 28, 2018
Fix warnings about the `native` target-cpu This fixes a regression from #53031 where specifying `-C target-cpu=native` is printing a lot of warnings from LLVM about `native` being an unknown CPU. It turns out that `native` is indeed an unknown CPU and we have to perform a mapping to an actual CPU name, but this mapping is only performed in one location rather than all locations we inform LLVM about the target CPU. This commit centralizes the mapping of `native` to LLVM's value of the native CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's never `native`. Closes #53322
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Aug 28, 2018
This fixes a regression from rust-lang#53031 where specifying `-C target-cpu=native` is printing a lot of warnings from LLVM about `native` being an unknown CPU. It turns out that `native` is indeed an unknown CPU and we have to perform a mapping to an actual CPU name, but this mapping is only performed in one location rather than all locations we inform LLVM about the target CPU. This commit centralizes the mapping of `native` to LLVM's value of the native CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's never `native`. Closes rust-lang#53322
bors
added a commit
that referenced
this pull request
Aug 29, 2018
Fix warnings about the `native` target-cpu This fixes a regression from #53031 where specifying `-C target-cpu=native` is printing a lot of warnings from LLVM about `native` being an unknown CPU. It turns out that `native` is indeed an unknown CPU and we have to perform a mapping to an actual CPU name, but this mapping is only performed in one location rather than all locations we inform LLVM about the target CPU. This commit centralizes the mapping of `native` to LLVM's value of the native CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's never `native`. Closes #53322
This was referenced Sep 3, 2018
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR contains a few fixes that were needed in order to get Firefox compiling with Rust/C++ cross-language ThinLTO on Windows. The commits are self-contained and should be self-explanatory.
r? @alexcrichton