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Auto merge of #125530 - SparrowLii:expand2, r=petrochenkov
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cleanup dependence of `ExtCtxt` in transcribe when macro expansion

part of #125356
We can remove `transcribe`’s dependence on `ExtCtxt` to facilitate subsequent work (such as moving macro expansion into the incremental compilation system)

r? `@petrochenkov`
Thanks for the reviewing!
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@bors
bors committed May 26, 2024
2 parents 5fe5543 + 2782123 commit a0a9ac9
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Showing 2 changed files with 31 additions and 32 deletions.
3 changes: 2 additions & 1 deletion compiler/rustc_expand/src/mbe/macro_rules.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -223,7 +223,8 @@ fn expand_macro<'cx>(
let arm_span = rhses[i].span();

// rhs has holes ( `$id` and `$(...)` that need filled)
let tts = match transcribe(cx, &named_matches, rhs, rhs_span, transparency) {
let id = cx.current_expansion.id;
let tts = match transcribe(psess, &named_matches, rhs, rhs_span, transparency, id) {
Ok(tts) => tts,
Err(err) => {
let guar = err.emit();
Expand Down
60 changes: 29 additions & 31 deletions compiler/rustc_expand/src/mbe/transcribe.rs
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,3 @@
use crate::base::ExtCtxt;
use crate::errors::{
CountRepetitionMisplaced, MetaVarExprUnrecognizedVar, MetaVarsDifSeqMatchers, MustRepeatOnce,
NoSyntaxVarsExprRepeat, VarStillRepeating,
Expand All @@ -9,12 +8,13 @@ use rustc_ast::mut_visit::{self, MutVisitor};
use rustc_ast::token::{self, Delimiter, Token, TokenKind};
use rustc_ast::tokenstream::{DelimSpacing, DelimSpan, Spacing, TokenStream, TokenTree};
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{pluralize, Diag, PResult};
use rustc_errors::{pluralize, Diag, DiagCtxt, PResult};
use rustc_parse::parser::ParseNtResult;
use rustc_span::hygiene::{LocalExpnId, Transparency};
use rustc_span::symbol::{sym, Ident, MacroRulesNormalizedIdent};
use rustc_span::{with_metavar_spans, Span, SyntaxContext};

use rustc_session::parse::ParseSess;
use smallvec::{smallvec, SmallVec};
use std::mem;

Expand Down Expand Up @@ -99,11 +99,12 @@ impl<'a> Iterator for Frame<'a> {
///
/// Along the way, we do some additional error checking.
pub(super) fn transcribe<'a>(
cx: &ExtCtxt<'a>,
psess: &'a ParseSess,
interp: &FxHashMap<MacroRulesNormalizedIdent, NamedMatch>,
src: &mbe::Delimited,
src_span: DelimSpan,
transparency: Transparency,
expand_id: LocalExpnId,
) -> PResult<'a, TokenStream> {
// Nothing for us to transcribe...
if src.tts.is_empty() {
Expand Down Expand Up @@ -137,8 +138,9 @@ pub(super) fn transcribe<'a>(
// again, and we are done transcribing.
let mut result: Vec<TokenTree> = Vec::new();
let mut result_stack = Vec::new();
let mut marker = Marker(cx.current_expansion.id, transparency, Default::default());
let mut marker = Marker(expand_id, transparency, Default::default());

let dcx = &psess.dcx;
loop {
// Look at the last frame on the stack.
// If it still has a TokenTree we have not looked at yet, use that tree.
Expand Down Expand Up @@ -201,19 +203,17 @@ pub(super) fn transcribe<'a>(
seq @ mbe::TokenTree::Sequence(_, seq_rep) => {
match lockstep_iter_size(seq, interp, &repeats) {
LockstepIterSize::Unconstrained => {
return Err(cx
.dcx()
.create_err(NoSyntaxVarsExprRepeat { span: seq.span() }));
return Err(dcx.create_err(NoSyntaxVarsExprRepeat { span: seq.span() }));
}

LockstepIterSize::Contradiction(msg) => {
// FIXME: this really ought to be caught at macro definition time... It
// happens when two meta-variables are used in the same repetition in a
// sequence, but they come from different sequence matchers and repeat
// different amounts.
return Err(cx
.dcx()
.create_err(MetaVarsDifSeqMatchers { span: seq.span(), msg }));
return Err(
dcx.create_err(MetaVarsDifSeqMatchers { span: seq.span(), msg })
);
}

LockstepIterSize::Constraint(len, _) => {
Expand All @@ -227,9 +227,7 @@ pub(super) fn transcribe<'a>(
// FIXME: this really ought to be caught at macro definition
// time... It happens when the Kleene operator in the matcher and
// the body for the same meta-variable do not match.
return Err(cx
.dcx()
.create_err(MustRepeatOnce { span: sp.entire() }));
return Err(dcx.create_err(MustRepeatOnce { span: sp.entire() }));
}
} else {
// 0 is the initial counter (we have done 0 repetitions so far). `len`
Expand Down Expand Up @@ -274,7 +272,7 @@ pub(super) fn transcribe<'a>(
MatchedSingle(ParseNtResult::Tt(tt)) => {
// `tt`s are emitted into the output stream directly as "raw tokens",
// without wrapping them into groups.
maybe_use_metavar_location(cx, &stack, sp, tt, &mut marker)
maybe_use_metavar_location(psess, &stack, sp, tt, &mut marker)
}
MatchedSingle(ParseNtResult::Ident(ident, is_raw)) => {
marker.visit_span(&mut sp);
Expand All @@ -295,7 +293,7 @@ pub(super) fn transcribe<'a>(
}
MatchedSeq(..) => {
// We were unable to descend far enough. This is an error.
return Err(cx.dcx().create_err(VarStillRepeating { span: sp, ident }));
return Err(dcx.create_err(VarStillRepeating { span: sp, ident }));
}
};
result.push(tt)
Expand All @@ -314,7 +312,7 @@ pub(super) fn transcribe<'a>(

// Replace meta-variable expressions with the result of their expansion.
mbe::TokenTree::MetaVarExpr(sp, expr) => {
transcribe_metavar_expr(cx, expr, interp, &mut marker, &repeats, &mut result, sp)?;
transcribe_metavar_expr(dcx, expr, interp, &mut marker, &repeats, &mut result, sp)?;
}

// If we are entering a new delimiter, we push its contents to the `stack` to be
Expand Down Expand Up @@ -374,7 +372,7 @@ pub(super) fn transcribe<'a>(
/// combine with each other and not with tokens outside of the sequence.
/// - The metavariable span comes from a different crate, then we prefer the more local span.
fn maybe_use_metavar_location(
cx: &ExtCtxt<'_>,
psess: &ParseSess,
stack: &[Frame<'_>],
mut metavar_span: Span,
orig_tt: &TokenTree,
Expand Down Expand Up @@ -412,7 +410,7 @@ fn maybe_use_metavar_location(
&& insert(mspans, dspan.entire(), metavar_span)
}),
};
if no_collision || cx.source_map().is_imported(metavar_span) {
if no_collision || psess.source_map().is_imported(metavar_span) {
return orig_tt.clone();
}

Expand Down Expand Up @@ -573,7 +571,7 @@ fn lockstep_iter_size(
/// * `[ $( ${count(foo, 1)} ),* ]` will return an error because `${count(foo, 1)}` is
/// declared inside a single repetition and the index `1` implies two nested repetitions.
fn count_repetitions<'a>(
cx: &ExtCtxt<'a>,
dcx: &'a DiagCtxt,
depth_user: usize,
mut matched: &NamedMatch,
repeats: &[(usize, usize)],
Expand Down Expand Up @@ -610,7 +608,7 @@ fn count_repetitions<'a>(
.and_then(|el| el.checked_sub(repeats.len()))
.unwrap_or_default();
if depth_user > depth_max {
return Err(out_of_bounds_err(cx, depth_max + 1, sp.entire(), "count"));
return Err(out_of_bounds_err(dcx, depth_max + 1, sp.entire(), "count"));
}

// `repeats` records all of the nested levels at which we are currently
Expand All @@ -626,15 +624,15 @@ fn count_repetitions<'a>(
}

if let MatchedSingle(_) = matched {
return Err(cx.dcx().create_err(CountRepetitionMisplaced { span: sp.entire() }));
return Err(dcx.create_err(CountRepetitionMisplaced { span: sp.entire() }));
}

count(depth_user, depth_max, matched)
}

/// Returns a `NamedMatch` item declared on the LHS given an arbitrary [Ident]
fn matched_from_ident<'ctx, 'interp, 'rslt>(
cx: &ExtCtxt<'ctx>,
dcx: &'ctx DiagCtxt,
ident: Ident,
interp: &'interp FxHashMap<MacroRulesNormalizedIdent, NamedMatch>,
) -> PResult<'ctx, &'rslt NamedMatch>
Expand All @@ -643,12 +641,12 @@ where
{
let span = ident.span;
let key = MacroRulesNormalizedIdent::new(ident);
interp.get(&key).ok_or_else(|| cx.dcx().create_err(MetaVarExprUnrecognizedVar { span, key }))
interp.get(&key).ok_or_else(|| dcx.create_err(MetaVarExprUnrecognizedVar { span, key }))
}

/// Used by meta-variable expressions when an user input is out of the actual declared bounds. For
/// example, index(999999) in an repetition of only three elements.
fn out_of_bounds_err<'a>(cx: &ExtCtxt<'a>, max: usize, span: Span, ty: &str) -> Diag<'a> {
fn out_of_bounds_err<'a>(dcx: &'a DiagCtxt, max: usize, span: Span, ty: &str) -> Diag<'a> {
let msg = if max == 0 {
format!(
"meta-variable expression `{ty}` with depth parameter \
Expand All @@ -660,11 +658,11 @@ fn out_of_bounds_err<'a>(cx: &ExtCtxt<'a>, max: usize, span: Span, ty: &str) ->
must be less than {max}"
)
};
cx.dcx().struct_span_err(span, msg)
dcx.struct_span_err(span, msg)
}

fn transcribe_metavar_expr<'a>(
cx: &ExtCtxt<'a>,
dcx: &'a DiagCtxt,
expr: &MetaVarExpr,
interp: &FxHashMap<MacroRulesNormalizedIdent, NamedMatch>,
marker: &mut Marker,
Expand All @@ -679,8 +677,8 @@ fn transcribe_metavar_expr<'a>(
};
match *expr {
MetaVarExpr::Count(original_ident, depth) => {
let matched = matched_from_ident(cx, original_ident, interp)?;
let count = count_repetitions(cx, depth, matched, repeats, sp)?;
let matched = matched_from_ident(dcx, original_ident, interp)?;
let count = count_repetitions(dcx, depth, matched, repeats, sp)?;
let tt = TokenTree::token_alone(
TokenKind::lit(token::Integer, sym::integer(count), None),
visited_span(),
Expand All @@ -689,7 +687,7 @@ fn transcribe_metavar_expr<'a>(
}
MetaVarExpr::Ignore(original_ident) => {
// Used to ensure that `original_ident` is present in the LHS
let _ = matched_from_ident(cx, original_ident, interp)?;
let _ = matched_from_ident(dcx, original_ident, interp)?;
}
MetaVarExpr::Index(depth) => match repeats.iter().nth_back(depth) {
Some((index, _)) => {
Expand All @@ -698,7 +696,7 @@ fn transcribe_metavar_expr<'a>(
visited_span(),
));
}
None => return Err(out_of_bounds_err(cx, repeats.len(), sp.entire(), "index")),
None => return Err(out_of_bounds_err(dcx, repeats.len(), sp.entire(), "index")),
},
MetaVarExpr::Len(depth) => match repeats.iter().nth_back(depth) {
Some((_, length)) => {
Expand All @@ -707,7 +705,7 @@ fn transcribe_metavar_expr<'a>(
visited_span(),
));
}
None => return Err(out_of_bounds_err(cx, repeats.len(), sp.entire(), "len")),
None => return Err(out_of_bounds_err(dcx, repeats.len(), sp.entire(), "len")),
},
}
Ok(())
Expand Down

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