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<h3 style="margin-top: 20px; margin-bottom: 10px;">
Matthew Pickering pushed to branch wip/compress-iface at <a href="https://gitlab.haskell.org/ghc/ghc">Glasgow Haskell Compiler / GHC</a>
</h3>
<h4 style="margin-top: 10px; margin-bottom: 10px;">
Commits:
</h4>
<ul>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/aa1ded09c016806ea32299272940166697dbd3da">aa1ded09</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2025-03-05T09:26:00+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Add flag to control whether self-recompilation information is written to interface
This patch adds the flag -fwrite-if-self-recomp which controls whether
interface files contain the information necessary to answer the
question:
Do I need to recompile myself or is this current interface file
suitable?
Why? Most packages are only built once either by a distribution or cabal
and then placed into an immutable store, after which we will never ask
this question. Therefore we can derive two benefits from omitting this
information.
* Primary motivation: It vastly reduces the surface area for creating
non-deterministic interface files. See issue #10424 which motivated a
proper fix to that issue. Distributions have long contained versions
of GHC which just have broken self-recompilation checking (in order to
get deterministic interface files).
* Secondary motivation: This reduces the size of interface files
slightly.. the `mi_usages` field can be quite big but probably this
isn't such a great benefit.
* Third motivation: Conceptually clarity about which parts of an
interface file are used in order to **communicate** with subsequent
packages about the **interface** for a module. And which parts are
used to self-communicate during recompilation checking.
The main tracking issue is #22188 but fixes issues such as #10424 in a
proper way.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/cf4972430f38429b07ca978faef21d3d4a17d12c">cf497243</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2025-03-05T09:26:20+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Disable self recomp in release flavour
The interface files that we distribute should not contain any
information which is used by the recompilation checking logic since
source file will never be compiled again.
I am not 100% sure this won't cause unexpected issues, there many be
downstream consumers which are incorrectly using the information from
interfaces, but this commit can be reverted if we detect issues.
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/70b5f1da951de72f23f57c2da99e8fabc0fb2ded">70b5f1da</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2025-03-05T09:26:20+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>iface: Store flags in interface files
When reporting the reason why a module is recompiled (using
`-dump-hi-diffs`), it is much more informative to inform the user about
which flag exactly has changed, rather than just an opaque reference to
a hash.
Now, when there is a difference the precise part of the flags is
reported:
```
codegen flags changed:
before: [Opt_NoTypeableBinds, Opt_OmitYields]
after: [Opt_NoTypeableBinds, Opt_OmitYields, Opt_DictsStrict]
```
Fixes #25571
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/7b6d2bad60595a25ae1d840f7ea990bd27c369b9">7b6d2bad</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2025-03-05T09:26:20+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>WIP: Compress interface files
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/e8c53993098751583cf621ad2a986960507904a5">e8c53993</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2025-03-05T09:26:20+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Fix
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/609d0e3d26e59c6e1f8855f911d53836e09930c0">609d0e3d</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2025-03-05T09:26:20+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>fix
</pre>
</li>
<li>
<strong style="font-weight: 600;"><a href="https://gitlab.haskell.org/ghc/ghc/-/commit/3d8858fbbc6db6d3e0322a405628654749b475d4">3d8858fb</a></strong>
<div>
<span> by Matthew Pickering </span> <i> at 2025-03-06T09:53:55+00:00 </i>
</div>
<pre class="commit-message" style='white-space: pre-wrap; display: block; font-size: 14px; color: #3a383f; position: relative; font-family: "GitLab Mono", "JetBrains Mono", "Menlo", "DejaVu Sans Mono", "Liberation Mono", "Consolas", "Ubuntu Mono", "Courier New", "andale mono", "lucida console", monospace; font-variant-ligatures: none; word-break: break-all; word-wrap: break-word; background-color: #fbfafd; border-radius: 2px; margin: 0; padding: 8px 12px; border: 1px solid #dcdcde;'>Load GHCi/UI.hs into multi-repl
</pre>
</li>
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