Windows Arm64 release build fails
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- Dominant language
- Python
- Stars
- 77.2k
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Description
There appears to be a compiler bug that causes build failures with optimization enabled when targeting ARM64 on Windows:
D:\a\1\s\Objects\unicodetype_db.h(4363): fatal error C1002: compiler is out of heap space in pass 2 [D:\a\1\s\PCbuild\pythoncore.vcxproj]
It repros reliably with cl /c /O2 Objects\unicodectype.c (with include dirs added), so I reported it to the C++ compiler team.
In the mean time, we'll disable optimizations for that file on ARM64 and hopefully that will get us through releases. Unless someone figures out a way to restructure the generated header to make the compiler happier, this is probably all we can do until the bug is fixed.
Linked PRs
- gh-153669
- gh-156081
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reviewing linked PRs gh-153669 and gh-156081, then inspect the ARM64 build configuration around PCbuild/pythoncore.vcxproj and Objects/unicodectype.c. Reproduce with cl /c /O2 Objects\unicodectype.c and verify that the Windows ARM64 release build completes without the compiler heap error.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- cpp
- Domain
- build-system, operating-systems, release
- Issue type
- Bug
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 25/100