build: ensure that Windows is built without PIC #6407
Merged
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
PIC on windows does not make sense. All code is position independent. Currently clang and LLVM do the wrong thing and generate ELF style PIC code on Windows when `-fPIC` is used. Add `-fno-pic` to disable that when cross-compiling to Windows.
|
@swift-ci please test and merge |
|
Not a review, but just a musing—even though PIC isn't the natural way of things for C code on Windows, there could be benefits to using a PIC/PIE-ish linkage model for Swift modules, since even with VM pager support for slid pages, there's still a nonzero cost to sliding and keeping resident multiple differently-slid copies of a page when an executable or DLL needs to be rebased. I suppose COFF objects might not have rich enough relocations for it, but it seems to me you could in theory craft a PE image with all the external references centralized to a GOT and PLT similar to ELF or Mach-O. |
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Outdated suggestions cannot be applied.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.
PIC on windows does not make sense. All code is position independent.
Currently clang and LLVM do the wrong thing and generate ELF style PIC
code on Windows when
-fPICis used. Add-fno-picto disable thatwhen cross-compiling to Windows.
Replace this paragraph with a description of your changes and rationale. Provide links to external references/discussions if appropriate.
Resolves SR-NNNN.