[libc] Enable wide-read memory operations by default on Linux #154602
Conversation
This file contains hidden or 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
jhuber6
requested review from
frobtech,
gchatelet,
lntue,
michaelrj-google,
petrhosek and
Sterling-Augustine
|
@llvm/pr-subscribers-libc Author: Joseph Huber (jhuber6) ChangesSummary: Full diff: https://github.com/llvm/llvm-project/pull/154602.diff 1 Files Affected:
diff --git a/libc/config/linux/config.json b/libc/config/linux/config.json
new file mode 100644
index 0000000000000..30e8b2cdadabe
--- /dev/null
+++ b/libc/config/linux/config.json
@@ -0,0 +1,7 @@
+{
+ "string": {
+ "LIBC_CONF_STRING_UNSAFE_WIDE_READ": {
+ "value": true
+ }
+ }
+}
|
|
Seems the AArch builder has some warnings that were never cleaned up. I'll try to fix those in this PR. |
jhuber6
force-pushed
the
wide
branch
3 times, most recently
from
8d8cc11 to
2208ffe
Compare
|
✅ With the latest revision this PR passed the C/C++ code formatter. |
jhuber6
force-pushed
the
wide
branch
2 times, most recently
from
3fda3ee to
03d371e
Compare
Summary: This patch changes the linux build to use the wide reads on the memory operations by default. These memory functions will now potentially read outside of the bounds explicitly allowed by the current function. While technically undefined behavior in the standard, plenty of C library implementations do this. it will not cause a segmentation fault on linux as long as you do not cross a page boundary, and because we are only *reading* memory it should not have atomic effects.
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/215/builds/3829 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/147/builds/27552 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/171/builds/28812 Here is the relevant piece of the build log for the reference |
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 20, 2025
llvm#154602)" This reverts commit 27fc967.
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 20, 2025
llvm#154602)" This reverts commit 27fc967.
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 20, 2025
llvm#154602)" This reverts commit 27fc967.
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 20, 2025
llvm#154602)" This reverts commit 27fc967.
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 20, 2025
llvm#154602)" This reverts commit 27fc967.
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 20, 2025
llvm#154602)" This reverts commit 27fc967.
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 21, 2025
llvm#154602)" This reverts commit 27fc967.
jhuber6
added a commit
to jhuber6/llvm-project
that referenced
this pull request
Aug 21, 2025
llvm#154602)" This reverts commit 27fc967.
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.
Summary:
This patch changes the linux build to use the wide reads on the memory
operations by default. These memory functions will now potentially read
outside of the bounds explicitly allowed by the current function. While
technically undefined behavior in the standard, plenty of C library
implementations do this. it will not cause a segmentation fault on linux
as long as you do not cross a page boundary, and because we are only
reading memory it should not have atomic effects.