bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Expand format_args!() in rust_ast_lowering.

Browse source
This commit is contained in:
Mara Bos 2023-01-11 21:41:13 +01:00
parent e83945150f
commit a4dbcb525b
19 changed files with 535 additions and 384 deletions
Download patch file Download diff file Expand all files Collapse all files

1
compiler/rustc_builtin_macros/src/assert/context.rs
View file

@ -297,6 +297,7 @@ impl<'cx, 'a> Context<'cx, 'a> {
| ExprKind::Continue(_)
| ExprKind::Err
| ExprKind::Field(_, _)
| ExprKind::FormatArgs(_)
| ExprKind::ForLoop(_, _, _, _)
| ExprKind::If(_, _, _)
| ExprKind::IncludedBytes(..)

14
compiler/rustc_builtin_macros/src/format.rs
View file

@ -1,7 +1,11 @@
use rustc_ast::ptr::P;
use rustc_ast::token;
use rustc_ast::tokenstream::TokenStream;
use rustc_ast::Expr;
use rustc_ast::{
Expr, ExprKind, FormatAlignment, FormatArgPosition, FormatArgPositionKind, FormatArgs,
FormatArgsPiece, FormatArgument, FormatArgumentKind, FormatArguments, FormatCount,
FormatOptions, FormatPlaceholder, FormatTrait,
};
use rustc_data_structures::fx::FxHashSet;
use rustc_errors::{pluralize, Applicability, MultiSpan, PResult};
use rustc_expand::base::{self, *};
@ -12,12 +16,6 @@ use rustc_span::{BytePos, InnerSpan, Span};
use rustc_lint_defs::builtin::NAMED_ARGUMENTS_USED_POSITIONALLY;
use rustc_lint_defs::{BufferedEarlyLint, BuiltinLintDiagnostics, LintId};
mod ast;
use ast::*;
mod expand;
use expand::expand_parsed_format_args;
// The format_args!() macro is expanded in three steps:
// 1. First, `parse_args` will parse the `(literal, arg, arg, name=arg, name=arg)` syntax,
// but doesn't parse the template (the literal) itself.
@ -850,7 +848,7 @@ fn expand_format_args_impl<'cx>(
match parse_args(ecx, sp, tts) {
Ok((efmt, args)) => {
if let Ok(format_args) = make_format_args(ecx, efmt, args, nl) {
MacEager::expr(expand_parsed_format_args(ecx, format_args))
MacEager::expr(ecx.expr(sp, ExprKind::FormatArgs(P(format_args))))
} else {
MacEager::expr(DummyResult::raw_expr(sp, true))
}

240
compiler/rustc_builtin_macros/src/format/ast.rs
View file

@ -1,240 +0,0 @@
use rustc_ast::ptr::P;
use rustc_ast::Expr;
use rustc_data_structures::fx::FxHashMap;
use rustc_span::symbol::{Ident, Symbol};
use rustc_span::Span;
// Definitions:
//
// format_args!("hello {abc:.xyz$}!!", abc="world");
// └──────────────────────────────────────────────┘
// FormatArgs
//
// format_args!("hello {abc:.xyz$}!!", abc="world");
// └─────────┘
// argument
//
// format_args!("hello {abc:.xyz$}!!", abc="world");
// └───────────────────┘
// template
//
// format_args!("hello {abc:.xyz$}!!", abc="world");
// └────┘└─────────┘└┘
// pieces
//
// format_args!("hello {abc:.xyz$}!!", abc="world");
// └────┘ └┘
// literal pieces
//
// format_args!("hello {abc:.xyz$}!!", abc="world");
// └─────────┘
// placeholder
//
// format_args!("hello {abc:.xyz$}!!", abc="world");
// └─┘ └─┘
// positions (could be names, numbers, empty, or `*`)
/// (Parsed) format args.
///
/// Basically the "AST" for a complete `format_args!()`.
///
/// E.g., `format_args!("hello {name}");`.
#[derive(Clone, Debug)]
pub struct FormatArgs {
pub span: Span,
pub template: Vec<FormatArgsPiece>,
pub arguments: FormatArguments,
}
/// A piece of a format template string.
///
/// E.g. "hello" or "{name}".
#[derive(Clone, Debug)]
pub enum FormatArgsPiece {
Literal(Symbol),
Placeholder(FormatPlaceholder),
}
/// The arguments to format_args!().
///
/// E.g. `1, 2, name="ferris", n=3`,
/// but also implicit captured arguments like `x` in `format_args!("{x}")`.
#[derive(Clone, Debug)]
pub struct FormatArguments {
arguments: Vec<FormatArgument>,
num_unnamed_args: usize,
num_explicit_args: usize,
names: FxHashMap<Symbol, usize>,
}
impl FormatArguments {
pub fn new() -> Self {
Self {
arguments: Vec::new(),
names: FxHashMap::default(),
num_unnamed_args: 0,
num_explicit_args: 0,
}
}
pub fn add(&mut self, arg: FormatArgument) -> usize {
let index = self.arguments.len();
if let Some(name) = arg.kind.ident() {
self.names.insert(name.name, index);
} else if self.names.is_empty() {
// Only count the unnamed args before the first named arg.
// (Any later ones are errors.)
self.num_unnamed_args += 1;
}
if !matches!(arg.kind, FormatArgumentKind::Captured(..)) {
// This is an explicit argument.
// Make sure that all arguments so far are explcit.
assert_eq!(
self.num_explicit_args,
self.arguments.len(),
"captured arguments must be added last"
);
self.num_explicit_args += 1;
}
self.arguments.push(arg);
index
}
pub fn by_name(&self, name: Symbol) -> Option<(usize, &FormatArgument)> {
let i = *self.names.get(&name)?;
Some((i, &self.arguments[i]))
}
pub fn by_index(&self, i: usize) -> Option<&FormatArgument> {
(i < self.num_explicit_args).then(|| &self.arguments[i])
}
pub fn unnamed_args(&self) -> &[FormatArgument] {
&self.arguments[..self.num_unnamed_args]
}
pub fn named_args(&self) -> &[FormatArgument] {
&self.arguments[self.num_unnamed_args..self.num_explicit_args]
}
pub fn explicit_args(&self) -> &[FormatArgument] {
&self.arguments[..self.num_explicit_args]
}
pub fn into_vec(self) -> Vec<FormatArgument> {
self.arguments
}
}
#[derive(Clone, Debug)]
pub struct FormatArgument {
pub kind: FormatArgumentKind,
pub expr: P<Expr>,
}
#[derive(Clone, Debug)]
pub enum FormatArgumentKind {
/// `format_args(…, arg)`
Normal,
/// `format_args(…, arg = 1)`
Named(Ident),
/// `format_args("… {arg} …")`
Captured(Ident),
}
impl FormatArgumentKind {
pub fn ident(&self) -> Option<Ident> {
match self {
&Self::Normal => None,
&Self::Named(id) => Some(id),
&Self::Captured(id) => Some(id),
}
}
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct FormatPlaceholder {
/// Index into [`FormatArgs::arguments`].
pub argument: FormatArgPosition,
/// The span inside the format string for the full `{…}` placeholder.
pub span: Option<Span>,
/// `{}`, `{:?}`, or `{:x}`, etc.
pub format_trait: FormatTrait,
/// `{}` or `{:.5}` or `{:-^20}`, etc.
pub format_options: FormatOptions,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct FormatArgPosition {
/// Which argument this position refers to (Ok),
/// or would've referred to if it existed (Err).
pub index: Result<usize, usize>,
/// What kind of position this is. See [`FormatArgPositionKind`].
pub kind: FormatArgPositionKind,
/// The span of the name or number.
pub span: Option<Span>,
}
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum FormatArgPositionKind {
/// `{}` or `{:.*}`
Implicit,
/// `{1}` or `{:1$}` or `{:.1$}`
Number,
/// `{a}` or `{:a$}` or `{:.a$}`
Named,
}
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq)]
pub enum FormatTrait {
/// `{}`
Display,
/// `{:?}`
Debug,
/// `{:e}`
LowerExp,
/// `{:E}`
UpperExp,
/// `{:o}`
Octal,
/// `{:p}`
Pointer,
/// `{:b}`
Binary,
/// `{:x}`
LowerHex,
/// `{:X}`
UpperHex,
}
#[derive(Clone, Debug, Default, PartialEq, Eq)]
pub struct FormatOptions {
/// The width. E.g. `{:5}` or `{:width$}`.
pub width: Option<FormatCount>,
/// The precision. E.g. `{:.5}` or `{:.precision$}`.
pub precision: Option<FormatCount>,
/// The alignment. E.g. `{:>}` or `{:<}` or `{:^}`.
pub alignment: Option<FormatAlignment>,
/// The fill character. E.g. the `.` in `{:.>10}`.
pub fill: Option<char>,
/// The `+`, `-`, `0`, `#`, `x?` and `X?` flags.
pub flags: u32,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum FormatAlignment {
/// `{:<}`
Left,
/// `{:>}`
Right,
/// `{:^}`
Center,
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum FormatCount {
/// `{:5}` or `{:.5}`
Literal(usize),
/// `{:.*}`, `{:.5$}`, or `{:a$}`, etc.
Argument(FormatArgPosition),
}

353
compiler/rustc_builtin_macros/src/format/expand.rs
View file

@ -1,353 +0,0 @@
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
}