diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_ast_lowering/src/format.rs | 194 |
1 files changed, 117 insertions, 77 deletions
diff --git a/compiler/rustc_ast_lowering/src/format.rs b/compiler/rustc_ast_lowering/src/format.rs index d2c3b8b2d56..ca4604c60c5 100644 --- a/compiler/rustc_ast_lowering/src/format.rs +++ b/compiler/rustc_ast_lowering/src/format.rs @@ -20,10 +20,126 @@ impl<'hir> LoweringContext<'_, 'hir> { let mut fmt = Cow::Borrowed(fmt); if self.tcx.sess.opts.unstable_opts.flatten_format_args { fmt = flatten_format_args(fmt); - fmt = inline_literals(fmt); + fmt = self.inline_literals(fmt); } expand_format_args(self, sp, &fmt, allow_const) } + + /// Try to convert a literal into an interned string + fn try_inline_lit(&self, lit: token::Lit) -> Option<Symbol> { + match LitKind::from_token_lit(lit) { + Ok(LitKind::Str(s, _)) => Some(s), + Ok(LitKind::Int(n, ty)) => { + match ty { + // unsuffixed integer literals are assumed to be i32's + LitIntType::Unsuffixed => { + (n <= i32::MAX as u128).then_some(Symbol::intern(&n.to_string())) + } + LitIntType::Signed(int_ty) => { + let max_literal = self.int_ty_max(int_ty); + (n <= max_literal).then_some(Symbol::intern(&n.to_string())) + } + LitIntType::Unsigned(uint_ty) => { + let max_literal = self.uint_ty_max(uint_ty); + (n <= max_literal).then_some(Symbol::intern(&n.to_string())) + } + } + } + _ => None, + } + } + + /// Get the maximum value of int_ty. It is platform-dependent due to the byte size of isize + fn int_ty_max(&self, int_ty: IntTy) -> u128 { + match int_ty { + IntTy::Isize => self.tcx.data_layout.pointer_size.signed_int_max() as u128, + IntTy::I8 => i8::MAX as u128, + IntTy::I16 => i16::MAX as u128, + IntTy::I32 => i32::MAX as u128, + IntTy::I64 => i64::MAX as u128, + IntTy::I128 => i128::MAX as u128, + } + } + + /// Get the maximum value of uint_ty. It is platform-dependent due to the byte size of usize + fn uint_ty_max(&self, uint_ty: UintTy) -> u128 { + match uint_ty { + UintTy::Usize => self.tcx.data_layout.pointer_size.unsigned_int_max(), + UintTy::U8 => u8::MAX as u128, + UintTy::U16 => u16::MAX as u128, + UintTy::U32 => u32::MAX as u128, + UintTy::U64 => u64::MAX as u128, + UintTy::U128 => u128::MAX as u128, + } + } + + /// Inline literals into the format string. + /// + /// Turns + /// + /// `format_args!("Hello, {}! {} {}", "World", 123, x)` + /// + /// into + /// + /// `format_args!("Hello, World! 123 {}", x)`. + fn inline_literals<'fmt>(&self, mut fmt: Cow<'fmt, FormatArgs>) -> Cow<'fmt, FormatArgs> { + let mut was_inlined = vec![false; fmt.arguments.all_args().len()]; + let mut inlined_anything = false; + + for i in 0..fmt.template.len() { + let FormatArgsPiece::Placeholder(placeholder) = &fmt.template[i] else { continue }; + let Ok(arg_index) = placeholder.argument.index else { continue }; + + let mut literal = None; + + if let FormatTrait::Display = placeholder.format_trait + && placeholder.format_options == Default::default() + && let arg = fmt.arguments.all_args()[arg_index].expr.peel_parens_and_refs() + && let ExprKind::Lit(lit) = arg.kind + { + literal = self.try_inline_lit(lit); + } + + if let Some(literal) = literal { + // Now we need to mutate the outer FormatArgs. + // If this is the first time, this clones the outer FormatArgs. + let fmt = fmt.to_mut(); + // Replace the placeholder with the literal. + fmt.template[i] = FormatArgsPiece::Literal(literal); + was_inlined[arg_index] = true; + inlined_anything = true; + } + } + + // Remove the arguments that were inlined. + if inlined_anything { + let fmt = fmt.to_mut(); + + let mut remove = was_inlined; + + // Don't remove anything that's still used. + for_all_argument_indexes(&mut fmt.template, |index| remove[*index] = false); + + // Drop all the arguments that are marked for removal. + let mut remove_it = remove.iter(); + fmt.arguments.all_args_mut().retain(|_| remove_it.next() != Some(&true)); + + // Calculate the mapping of old to new indexes for the remaining arguments. + let index_map: Vec<usize> = remove + .into_iter() + .scan(0, |i, remove| { + let mapped = *i; + *i += !remove as usize; + Some(mapped) + }) + .collect(); + + // Correct the indexes that refer to arguments that have shifted position. + for_all_argument_indexes(&mut fmt.template, |index| *index = index_map[*index]); + } + + fmt + } } /// Flattens nested `format_args!()` into one. @@ -103,82 +219,6 @@ fn flatten_format_args(mut fmt: Cow<'_, FormatArgs>) -> Cow<'_, FormatArgs> { fmt } -/// Inline literals into the format string. -/// -/// Turns -/// -/// `format_args!("Hello, {}! {} {}", "World", 123, x)` -/// -/// into -/// -/// `format_args!("Hello, World! 123 {}", x)`. -fn inline_literals(mut fmt: Cow<'_, FormatArgs>) -> Cow<'_, FormatArgs> { - let mut was_inlined = vec![false; fmt.arguments.all_args().len()]; - let mut inlined_anything = false; - - for i in 0..fmt.template.len() { - let FormatArgsPiece::Placeholder(placeholder) = &fmt.template[i] else { continue }; - let Ok(arg_index) = placeholder.argument.index else { continue }; - - let mut literal = None; - - if let FormatTrait::Display = placeholder.format_trait - && placeholder.format_options == Default::default() - && let arg = fmt.arguments.all_args()[arg_index].expr.peel_parens_and_refs() - && let ExprKind::Lit(lit) = arg.kind - { - if let token::LitKind::Str | token::LitKind::StrRaw(_) = lit.kind - && let Ok(LitKind::Str(s, _)) = LitKind::from_token_lit(lit) - { - literal = Some(s); - } else if let token::LitKind::Integer = lit.kind - && let Ok(LitKind::Int(n, _)) = LitKind::from_token_lit(lit) - { - literal = Some(Symbol::intern(&n.to_string())); - } - } - - if let Some(literal) = literal { - // Now we need to mutate the outer FormatArgs. - // If this is the first time, this clones the outer FormatArgs. - let fmt = fmt.to_mut(); - // Replace the placeholder with the literal. - fmt.template[i] = FormatArgsPiece::Literal(literal); - was_inlined[arg_index] = true; - inlined_anything = true; - } - } - - // Remove the arguments that were inlined. - if inlined_anything { - let fmt = fmt.to_mut(); - - let mut remove = was_inlined; - - // Don't remove anything that's still used. - for_all_argument_indexes(&mut fmt.template, |index| remove[*index] = false); - - // Drop all the arguments that are marked for removal. - let mut remove_it = remove.iter(); - fmt.arguments.all_args_mut().retain(|_| remove_it.next() != Some(&true)); - - // Calculate the mapping of old to new indexes for the remaining arguments. - let index_map: Vec<usize> = remove - .into_iter() - .scan(0, |i, remove| { - let mapped = *i; - *i += !remove as usize; - Some(mapped) - }) - .collect(); - - // Correct the indexes that refer to arguments that have shifted position. - for_all_argument_indexes(&mut fmt.template, |index| *index = index_map[*index]); - } - - fmt -} - #[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)] enum ArgumentType { Format(FormatTrait), |