feat: support the DEFINED command in linker scripts#2181
Open
vishruth-thimmaiah wants to merge 2 commits into
Open
feat: support the DEFINED command in linker scripts#2181vishruth-thimmaiah wants to merge 2 commits into
vishruth-thimmaiah wants to merge 2 commits into
Conversation
Signed-off-by: Vishruth Thimmaiah <vishruththimmaiah@gmail.com>
| } | ||
| } | ||
| Expression::Defined(name) => Ok(symbol_db | ||
| .get_unversioned(&UnversionedSymbolName::prehashed(name)) |
Member
There was a problem hiding this comment.
I'm not sure that this will do the correct thing if there are objects that reference, but don't define the symbol. Can you add a test for that? i.e. have an object that has a weak reference to the symbol.
Signed-off-by: Vishruth Thimmaiah <vishruththimmaiah@gmail.com>
| void _start() {} | ||
|
|
||
| int symbol4 = 0x4000; | ||
| int symbol6 __attribute__((weak)); |
Member
There was a problem hiding this comment.
Note that declaring a variable doesn't create a reference to it - you need to actually have some code that uses the variable for it to end up in the symbol table.
Member
There was a problem hiding this comment.
You can verify this by running readelf -Ws on the object file to see what undefined symbols are listed.
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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 adds support for the
DEFINEDcommand in linker scripts, which is used to check if a symbol has been declared or not.