diff options
Diffstat (limited to 'compiler/rustc_builtin_macros/src/format/expand.rs')
| -rw-r--r-- | compiler/rustc_builtin_macros/src/format/expand.rs | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/compiler/rustc_builtin_macros/src/format/expand.rs b/compiler/rustc_builtin_macros/src/format/expand.rs new file mode 100644 index 000000000..9dde5efcb --- /dev/null +++ b/compiler/rustc_builtin_macros/src/format/expand.rs @@ -0,0 +1,353 @@ +use super::*; +use rustc_ast as ast; +use rustc_ast::visit::{self, Visitor}; +use rustc_ast::{BlockCheckMode, UnsafeSource}; +use rustc_data_structures::fx::FxIndexSet; +use rustc_span::{sym, symbol::kw}; + +#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)] +enum ArgumentType { + Format(FormatTrait), + Usize, +} + +fn make_argument(ecx: &ExtCtxt<'_>, sp: Span, arg: P<ast::Expr>, ty: ArgumentType) -> P<ast::Expr> { + // Generate: + // ::core::fmt::ArgumentV1::new_…(arg) + use ArgumentType::*; + use FormatTrait::*; + ecx.expr_call_global( + sp, + ecx.std_path(&[ + sym::fmt, + sym::ArgumentV1, + match ty { + Format(Display) => sym::new_display, + Format(Debug) => sym::new_debug, + Format(LowerExp) => sym::new_lower_exp, + Format(UpperExp) => sym::new_upper_exp, + Format(Octal) => sym::new_octal, + Format(Pointer) => sym::new_pointer, + Format(Binary) => sym::new_binary, + Format(LowerHex) => sym::new_lower_hex, + Format(UpperHex) => sym::new_upper_hex, + Usize => sym::from_usize, + }, + ]), + vec![arg], + ) +} + +fn make_count( + ecx: &ExtCtxt<'_>, + sp: Span, + count: &Option<FormatCount>, + argmap: &mut FxIndexSet<(usize, ArgumentType)>, +) -> P<ast::Expr> { + // Generate: + // ::core::fmt::rt::v1::Count::…(…) + match count { + Some(FormatCount::Literal(n)) => ecx.expr_call_global( + sp, + ecx.std_path(&[sym::fmt, sym::rt, sym::v1, sym::Count, sym::Is]), + vec![ecx.expr_usize(sp, *n)], + ), + Some(FormatCount::Argument(arg)) => { + if let Ok(arg_index) = arg.index { + let (i, _) = argmap.insert_full((arg_index, ArgumentType::Usize)); + ecx.expr_call_global( + sp, + ecx.std_path(&[sym::fmt, sym::rt, sym::v1, sym::Count, sym::Param]), + vec![ecx.expr_usize(sp, i)], + ) + } else { + DummyResult::raw_expr(sp, true) + } + } + None => ecx.expr_path(ecx.path_global( + sp, + ecx.std_path(&[sym::fmt, sym::rt, sym::v1, sym::Count, sym::Implied]), + )), + } +} + +fn make_format_spec( + ecx: &ExtCtxt<'_>, + sp: Span, + placeholder: &FormatPlaceholder, + argmap: &mut FxIndexSet<(usize, ArgumentType)>, +) -> P<ast::Expr> { + // Generate: + // ::core::fmt::rt::v1::Argument { + // position: 0usize, + // format: ::core::fmt::rt::v1::FormatSpec { + // fill: ' ', + // align: ::core::fmt::rt::v1::Alignment::Unknown, + // flags: 0u32, + // precision: ::core::fmt::rt::v1::Count::Implied, + // width: ::core::fmt::rt::v1::Count::Implied, + // }, + // } + let position = match placeholder.argument.index { + Ok(arg_index) => { + let (i, _) = + argmap.insert_full((arg_index, ArgumentType::Format(placeholder.format_trait))); + ecx.expr_usize(sp, i) + } + Err(_) => DummyResult::raw_expr(sp, true), + }; + let fill = ecx.expr_char(sp, placeholder.format_options.fill.unwrap_or(' ')); + let align = ecx.expr_path(ecx.path_global( + sp, + ecx.std_path(&[ + sym::fmt, + sym::rt, + sym::v1, + sym::Alignment, + match placeholder.format_options.alignment { + Some(FormatAlignment::Left) => sym::Left, + Some(FormatAlignment::Right) => sym::Right, + Some(FormatAlignment::Center) => sym::Center, + None => sym::Unknown, + }, + ]), + )); + let flags = ecx.expr_u32(sp, placeholder.format_options.flags); + let prec = make_count(ecx, sp, &placeholder.format_options.precision, argmap); + let width = make_count(ecx, sp, &placeholder.format_options.width, argmap); + ecx.expr_struct( + sp, + ecx.path_global(sp, ecx.std_path(&[sym::fmt, sym::rt, sym::v1, sym::Argument])), + vec![ + ecx.field_imm(sp, Ident::new(sym::position, sp), position), + ecx.field_imm( + sp, + Ident::new(sym::format, sp), + ecx.expr_struct( + sp, + ecx.path_global( + sp, + ecx.std_path(&[sym::fmt, sym::rt, sym::v1, sym::FormatSpec]), + ), + vec![ + ecx.field_imm(sp, Ident::new(sym::fill, sp), fill), + ecx.field_imm(sp, Ident::new(sym::align, sp), align), + ecx.field_imm(sp, Ident::new(sym::flags, sp), flags), + ecx.field_imm(sp, Ident::new(sym::precision, sp), prec), + ecx.field_imm(sp, Ident::new(sym::width, sp), width), + ], + ), + ), + ], + ) +} + +pub fn expand_parsed_format_args(ecx: &mut ExtCtxt<'_>, fmt: FormatArgs) -> P<ast::Expr> { + let macsp = ecx.with_def_site_ctxt(ecx.call_site()); + + let lit_pieces = ecx.expr_array_ref( + fmt.span, + fmt.template + .iter() + .enumerate() + .filter_map(|(i, piece)| match piece { + &FormatArgsPiece::Literal(s) => Some(ecx.expr_str(fmt.span, s)), + &FormatArgsPiece::Placeholder(_) => { + // Inject empty string before placeholders when not already preceded by a literal piece. + if i == 0 || matches!(fmt.template[i - 1], FormatArgsPiece::Placeholder(_)) { + Some(ecx.expr_str(fmt.span, kw::Empty)) + } else { + None + } + } + }) + .collect(), + ); + + // Whether we'll use the `Arguments::new_v1_formatted` form (true), + // or the `Arguments::new_v1` form (false). + let mut use_format_options = false; + + // Create a list of all _unique_ (argument, format trait) combinations. + // E.g. "{0} {0:x} {0} {1}" -> [(0, Display), (0, LowerHex), (1, Display)] + let mut argmap = FxIndexSet::default(); + for piece in &fmt.template { + let FormatArgsPiece::Placeholder(placeholder) = piece else { continue }; + if placeholder.format_options != Default::default() { + // Can't use basic form if there's any formatting options. + use_format_options = true; + } + if let Ok(index) = placeholder.argument.index { + if !argmap.insert((index, ArgumentType::Format(placeholder.format_trait))) { + // Duplicate (argument, format trait) combination, + // which we'll only put once in the args array. + use_format_options = true; + } + } + } + + let format_options = use_format_options.then(|| { + // Generate: + // &[format_spec_0, format_spec_1, format_spec_2] + ecx.expr_array_ref( + macsp, + fmt.template + .iter() + .filter_map(|piece| { + let FormatArgsPiece::Placeholder(placeholder) = piece else { return None }; + Some(make_format_spec(ecx, macsp, placeholder, &mut argmap)) + }) + .collect(), + ) + }); + + let arguments = fmt.arguments.into_vec(); + + // If the args array contains exactly all the original arguments once, + // in order, we can use a simple array instead of a `match` construction. + // However, if there's a yield point in any argument except the first one, + // we don't do this, because an ArgumentV1 cannot be kept across yield points. + let use_simple_array = argmap.len() == arguments.len() + && argmap.iter().enumerate().all(|(i, &(j, _))| i == j) + && arguments.iter().skip(1).all(|arg| !may_contain_yield_point(&arg.expr)); + + let args = if use_simple_array { + // Generate: + // &[ + // ::core::fmt::ArgumentV1::new_display(&arg0), + // ::core::fmt::ArgumentV1::new_lower_hex(&arg1), + // ::core::fmt::ArgumentV1::new_debug(&arg2), + // ] + ecx.expr_array_ref( + macsp, + arguments + .into_iter() + .zip(argmap) + .map(|(arg, (_, ty))| { + let sp = arg.expr.span.with_ctxt(macsp.ctxt()); + make_argument(ecx, sp, ecx.expr_addr_of(sp, arg.expr), ty) + }) + .collect(), + ) + } else { + // Generate: + // match (&arg0, &arg1, &arg2) { + // args => &[ + // ::core::fmt::ArgumentV1::new_display(args.0), + // ::core::fmt::ArgumentV1::new_lower_hex(args.1), + // ::core::fmt::ArgumentV1::new_debug(args.0), + // ] + // } + let args_ident = Ident::new(sym::args, macsp); + let args = argmap + .iter() + .map(|&(arg_index, ty)| { + if let Some(arg) = arguments.get(arg_index) { + let sp = arg.expr.span.with_ctxt(macsp.ctxt()); + make_argument( + ecx, + sp, + ecx.expr_field( + sp, + ecx.expr_ident(macsp, args_ident), + Ident::new(sym::integer(arg_index), macsp), + ), + ty, + ) + } else { + DummyResult::raw_expr(macsp, true) + } + }) + .collect(); + ecx.expr_addr_of( + macsp, + ecx.expr_match( + macsp, + ecx.expr_tuple( + macsp, + arguments + .into_iter() + .map(|arg| { + ecx.expr_addr_of(arg.expr.span.with_ctxt(macsp.ctxt()), arg.expr) + }) + .collect(), + ), + vec![ecx.arm(macsp, ecx.pat_ident(macsp, args_ident), ecx.expr_array(macsp, args))], + ), + ) + }; + + if let Some(format_options) = format_options { + // Generate: + // ::core::fmt::Arguments::new_v1_formatted( + // lit_pieces, + // args, + // format_options, + // unsafe { ::core::fmt::UnsafeArg::new() } + // ) + ecx.expr_call_global( + macsp, + ecx.std_path(&[sym::fmt, sym::Arguments, sym::new_v1_formatted]), + vec![ + lit_pieces, + args, + format_options, + ecx.expr_block(P(ast::Block { + stmts: vec![ecx.stmt_expr(ecx.expr_call_global( + macsp, + ecx.std_path(&[sym::fmt, sym::UnsafeArg, sym::new]), + Vec::new(), + ))], + id: ast::DUMMY_NODE_ID, + rules: BlockCheckMode::Unsafe(UnsafeSource::CompilerGenerated), + span: macsp, + tokens: None, + could_be_bare_literal: false, + })), + ], + ) + } else { + // Generate: + // ::core::fmt::Arguments::new_v1( + // lit_pieces, + // args, + // ) + ecx.expr_call_global( + macsp, + ecx.std_path(&[sym::fmt, sym::Arguments, sym::new_v1]), + vec![lit_pieces, args], + ) + } +} + +fn may_contain_yield_point(e: &ast::Expr) -> bool { + struct MayContainYieldPoint(bool); + + impl Visitor<'_> for MayContainYieldPoint { + fn visit_expr(&mut self, e: &ast::Expr) { + if let ast::ExprKind::Await(_) | ast::ExprKind::Yield(_) = e.kind { + self.0 = true; + } else { + visit::walk_expr(self, e); + } + } + + fn visit_mac_call(&mut self, _: &ast::MacCall) { + self.0 = true; + } + + fn visit_attribute(&mut self, _: &ast::Attribute) { + // Conservatively assume this may be a proc macro attribute in + // expression position. + self.0 = true; + } + + fn visit_item(&mut self, _: &ast::Item) { + // Do not recurse into nested items. + } + } + + let mut visitor = MayContainYieldPoint(false); + visitor.visit_expr(e); + visitor.0 +} |