Use the reference grammar for inline assembly #1807
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
This rule doesn't just apply to `asm!` but all of the macros.
This updates the inline assembly grammar description to use the grammar
style used in the rest of the reference, which also supports diagrams. I
also appreciate that this is more precisely defined using existing
grammar productions.
I realize that this is not as compressed as before. If that is a real
problem, then I think we can look at improving that throughout the
reference in general.
I did not change other parts of the chapter even though they mention
things like `in(<reg>) <expr>`. I could rewrite those, though I'm not
sure if that would help a lot.
There are restrictions not captured in the grammar which are explained
in the text. For example, global_asm and naked_asm do not allow
clobber_abi. I think I'm fine with the grammar not including everything
since there isn't the concept of an AST here.
This is not a direct translation because the old grammar was not
entirely precise or match with the existing grammar. This also renames
the rules to use PascalCase. The exhaustive list of differences:
Removed:
- Removed the `asm`, `naked_asm` and `global_asm` rules since I don't
think they really added anything, and the macro names aren't exactly
part of the grammar being described here. Instead it is just
`AsmArgs`.
- Removed the explicit `_` since that is now a normal Expression.
New:
- FormatString added MacroInvocation because that is supported.
- Defined AbiString.
- Defined RegisterClass.
- Defined ExplicitRegister.
Changed:
- Renamed option and options to AsmOption and AsmOptions (since our
namespace is global).
- Clarified the meaning of "ident".
- ArgName allows ident, keywords, and raw identifiers.
- RegisterClass allows ident, keywords, but NOT raw identifiers.
- Split DirSpec into two, since there is a separate
`Expression => Expression` syntax that is only valid for a subset
of DirSpecs.
- Clarified that `sym` takes a PathExpression.
- Clarified that label's block doesn't allow inner attributes.
- Fixed sym/const/label which weren't properly quoted.
- Fixed some ambiguous precedence like alternation in reg_operand.
rustbot
added
the
S-waiting-on-review
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.
This updates the inline assembly grammar description to use the grammar style used in the rest of the reference, which also supports diagrams.
See the commit message for a detailed breakdown.