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Diffstat (limited to 'src/libsyntax_expand/base.rs')
| -rw-r--r-- | src/libsyntax_expand/base.rs | 1189 |
1 files changed, 1189 insertions, 0 deletions
diff --git a/src/libsyntax_expand/base.rs b/src/libsyntax_expand/base.rs new file mode 100644 index 00000000000..593e06f29b9 --- /dev/null +++ b/src/libsyntax_expand/base.rs @@ -0,0 +1,1189 @@ +use crate::expand::{self, AstFragment, Invocation}; +use crate::hygiene::ExpnId; + +use syntax::ast::{self, NodeId, Attribute, Name, PatKind}; +use syntax::attr::{self, HasAttrs, Stability, Deprecation}; +use syntax::source_map::SourceMap; +use syntax::edition::Edition; +use syntax::mut_visit::{self, MutVisitor}; +use syntax::parse::{self, parser, DirectoryOwnership}; +use syntax::parse::token; +use syntax::ptr::P; +use syntax::sess::ParseSess; +use syntax::symbol::{kw, sym, Ident, Symbol}; +use syntax::{ThinVec, MACRO_ARGUMENTS}; +use syntax::tokenstream::{self, TokenStream}; +use syntax::visit::Visitor; + +use errors::{DiagnosticBuilder, DiagnosticId}; +use smallvec::{smallvec, SmallVec}; +use syntax_pos::{FileName, Span, MultiSpan, DUMMY_SP}; +use syntax_pos::hygiene::{AstPass, ExpnData, ExpnKind}; + +use rustc_data_structures::fx::FxHashMap; +use rustc_data_structures::sync::{self, Lrc}; +use std::iter; +use std::path::PathBuf; +use std::rc::Rc; +use std::default::Default; + +pub use syntax_pos::hygiene::MacroKind; + +#[derive(Debug,Clone)] +pub enum Annotatable { + Item(P<ast::Item>), + TraitItem(P<ast::TraitItem>), + ImplItem(P<ast::ImplItem>), + ForeignItem(P<ast::ForeignItem>), + Stmt(P<ast::Stmt>), + Expr(P<ast::Expr>), + Arm(ast::Arm), + Field(ast::Field), + FieldPat(ast::FieldPat), + GenericParam(ast::GenericParam), + Param(ast::Param), + StructField(ast::StructField), + Variant(ast::Variant), +} + +impl HasAttrs for Annotatable { + fn attrs(&self) -> &[Attribute] { + match *self { + Annotatable::Item(ref item) => &item.attrs, + Annotatable::TraitItem(ref trait_item) => &trait_item.attrs, + Annotatable::ImplItem(ref impl_item) => &impl_item.attrs, + Annotatable::ForeignItem(ref foreign_item) => &foreign_item.attrs, + Annotatable::Stmt(ref stmt) => stmt.attrs(), + Annotatable::Expr(ref expr) => &expr.attrs, + Annotatable::Arm(ref arm) => &arm.attrs, + Annotatable::Field(ref field) => &field.attrs, + Annotatable::FieldPat(ref fp) => &fp.attrs, + Annotatable::GenericParam(ref gp) => &gp.attrs, + Annotatable::Param(ref p) => &p.attrs, + Annotatable::StructField(ref sf) => &sf.attrs, + Annotatable::Variant(ref v) => &v.attrs(), + } + } + + fn visit_attrs<F: FnOnce(&mut Vec<Attribute>)>(&mut self, f: F) { + match self { + Annotatable::Item(item) => item.visit_attrs(f), + Annotatable::TraitItem(trait_item) => trait_item.visit_attrs(f), + Annotatable::ImplItem(impl_item) => impl_item.visit_attrs(f), + Annotatable::ForeignItem(foreign_item) => foreign_item.visit_attrs(f), + Annotatable::Stmt(stmt) => stmt.visit_attrs(f), + Annotatable::Expr(expr) => expr.visit_attrs(f), + Annotatable::Arm(arm) => arm.visit_attrs(f), + Annotatable::Field(field) => field.visit_attrs(f), + Annotatable::FieldPat(fp) => fp.visit_attrs(f), + Annotatable::GenericParam(gp) => gp.visit_attrs(f), + Annotatable::Param(p) => p.visit_attrs(f), + Annotatable::StructField(sf) => sf.visit_attrs(f), + Annotatable::Variant(v) => v.visit_attrs(f), + } + } +} + +impl Annotatable { + pub fn span(&self) -> Span { + match *self { + Annotatable::Item(ref item) => item.span, + Annotatable::TraitItem(ref trait_item) => trait_item.span, + Annotatable::ImplItem(ref impl_item) => impl_item.span, + Annotatable::ForeignItem(ref foreign_item) => foreign_item.span, + Annotatable::Stmt(ref stmt) => stmt.span, + Annotatable::Expr(ref expr) => expr.span, + Annotatable::Arm(ref arm) => arm.span, + Annotatable::Field(ref field) => field.span, + Annotatable::FieldPat(ref fp) => fp.pat.span, + Annotatable::GenericParam(ref gp) => gp.ident.span, + Annotatable::Param(ref p) => p.span, + Annotatable::StructField(ref sf) => sf.span, + Annotatable::Variant(ref v) => v.span, + } + } + + pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) { + match self { + Annotatable::Item(item) => visitor.visit_item(item), + Annotatable::TraitItem(trait_item) => visitor.visit_trait_item(trait_item), + Annotatable::ImplItem(impl_item) => visitor.visit_impl_item(impl_item), + Annotatable::ForeignItem(foreign_item) => visitor.visit_foreign_item(foreign_item), + Annotatable::Stmt(stmt) => visitor.visit_stmt(stmt), + Annotatable::Expr(expr) => visitor.visit_expr(expr), + Annotatable::Arm(arm) => visitor.visit_arm(arm), + Annotatable::Field(field) => visitor.visit_field(field), + Annotatable::FieldPat(fp) => visitor.visit_field_pattern(fp), + Annotatable::GenericParam(gp) => visitor.visit_generic_param(gp), + Annotatable::Param(p) => visitor.visit_param(p), + Annotatable::StructField(sf) =>visitor.visit_struct_field(sf), + Annotatable::Variant(v) => visitor.visit_variant(v), + } + } + + pub fn expect_item(self) -> P<ast::Item> { + match self { + Annotatable::Item(i) => i, + _ => panic!("expected Item") + } + } + + pub fn map_item_or<F, G>(self, mut f: F, mut or: G) -> Annotatable + where F: FnMut(P<ast::Item>) -> P<ast::Item>, + G: FnMut(Annotatable) -> Annotatable + { + match self { + Annotatable::Item(i) => Annotatable::Item(f(i)), + _ => or(self) + } + } + + pub fn expect_trait_item(self) -> ast::TraitItem { + match self { + Annotatable::TraitItem(i) => i.into_inner(), + _ => panic!("expected Item") + } + } + + pub fn expect_impl_item(self) -> ast::ImplItem { + match self { + Annotatable::ImplItem(i) => i.into_inner(), + _ => panic!("expected Item") + } + } + + pub fn expect_foreign_item(self) -> ast::ForeignItem { + match self { + Annotatable::ForeignItem(i) => i.into_inner(), + _ => panic!("expected foreign item") + } + } + + pub fn expect_stmt(self) -> ast::Stmt { + match self { + Annotatable::Stmt(stmt) => stmt.into_inner(), + _ => panic!("expected statement"), + } + } + + pub fn expect_expr(self) -> P<ast::Expr> { + match self { + Annotatable::Expr(expr) => expr, + _ => panic!("expected expression"), + } + } + + pub fn expect_arm(self) -> ast::Arm { + match self { + Annotatable::Arm(arm) => arm, + _ => panic!("expected match arm") + } + } + + pub fn expect_field(self) -> ast::Field { + match self { + Annotatable::Field(field) => field, + _ => panic!("expected field") + } + } + + pub fn expect_field_pattern(self) -> ast::FieldPat { + match self { + Annotatable::FieldPat(fp) => fp, + _ => panic!("expected field pattern") + } + } + + pub fn expect_generic_param(self) -> ast::GenericParam { + match self { + Annotatable::GenericParam(gp) => gp, + _ => panic!("expected generic parameter") + } + } + + pub fn expect_param(self) -> ast::Param { + match self { + Annotatable::Param(param) => param, + _ => panic!("expected parameter") + } + } + + pub fn expect_struct_field(self) -> ast::StructField { + match self { + Annotatable::StructField(sf) => sf, + _ => panic!("expected struct field") + } + } + + pub fn expect_variant(self) -> ast::Variant { + match self { + Annotatable::Variant(v) => v, + _ => panic!("expected variant") + } + } + + pub fn derive_allowed(&self) -> bool { + match *self { + Annotatable::Item(ref item) => match item.kind { + ast::ItemKind::Struct(..) | + ast::ItemKind::Enum(..) | + ast::ItemKind::Union(..) => true, + _ => false, + }, + _ => false, + } + } +} + +// `meta_item` is the annotation, and `item` is the item being modified. +// FIXME Decorators should follow the same pattern too. +pub trait MultiItemModifier { + fn expand(&self, + ecx: &mut ExtCtxt<'_>, + span: Span, + meta_item: &ast::MetaItem, + item: Annotatable) + -> Vec<Annotatable>; +} + +impl<F, T> MultiItemModifier for F + where F: Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, Annotatable) -> T, + T: Into<Vec<Annotatable>>, +{ + fn expand(&self, + ecx: &mut ExtCtxt<'_>, + span: Span, + meta_item: &ast::MetaItem, + item: Annotatable) + -> Vec<Annotatable> { + (*self)(ecx, span, meta_item, item).into() + } +} + +impl Into<Vec<Annotatable>> for Annotatable { + fn into(self) -> Vec<Annotatable> { + vec![self] + } +} + +pub trait ProcMacro { + fn expand<'cx>(&self, + ecx: &'cx mut ExtCtxt<'_>, + span: Span, + ts: TokenStream) + -> TokenStream; +} + +impl<F> ProcMacro for F + where F: Fn(TokenStream) -> TokenStream +{ + fn expand<'cx>(&self, + _ecx: &'cx mut ExtCtxt<'_>, + _span: Span, + ts: TokenStream) + -> TokenStream { + // FIXME setup implicit context in TLS before calling self. + (*self)(ts) + } +} + +pub trait AttrProcMacro { + fn expand<'cx>(&self, + ecx: &'cx mut ExtCtxt<'_>, + span: Span, + annotation: TokenStream, + annotated: TokenStream) + -> TokenStream; +} + +impl<F> AttrProcMacro for F + where F: Fn(TokenStream, TokenStream) -> TokenStream +{ + fn expand<'cx>(&self, + _ecx: &'cx mut ExtCtxt<'_>, + _span: Span, + annotation: TokenStream, + annotated: TokenStream) + -> TokenStream { + // FIXME setup implicit context in TLS before calling self. + (*self)(annotation, annotated) + } +} + +/// Represents a thing that maps token trees to Macro Results +pub trait TTMacroExpander { + fn expand<'cx>( + &self, + ecx: &'cx mut ExtCtxt<'_>, + span: Span, + input: TokenStream, + ) -> Box<dyn MacResult+'cx>; +} + +pub type MacroExpanderFn = + for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) + -> Box<dyn MacResult+'cx>; + +impl<F> TTMacroExpander for F + where F: for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, TokenStream) + -> Box<dyn MacResult+'cx> +{ + fn expand<'cx>( + &self, + ecx: &'cx mut ExtCtxt<'_>, + span: Span, + mut input: TokenStream, + ) -> Box<dyn MacResult+'cx> { + struct AvoidInterpolatedIdents; + + impl MutVisitor for AvoidInterpolatedIdents { + fn visit_tt(&mut self, tt: &mut tokenstream::TokenTree) { + if let tokenstream::TokenTree::Token(token) = tt { + if let token::Interpolated(nt) = &token.kind { + if let token::NtIdent(ident, is_raw) = **nt { + *tt = tokenstream::TokenTree::token( + token::Ident(ident.name, is_raw), ident.span + ); + } + } + } + mut_visit::noop_visit_tt(tt, self) + } + + fn visit_mac(&mut self, mac: &mut ast::Mac) { + mut_visit::noop_visit_mac(mac, self) + } + } + AvoidInterpolatedIdents.visit_tts(&mut input); + (*self)(ecx, span, input) + } +} + +// Use a macro because forwarding to a simple function has type system issues +macro_rules! make_stmts_default { + ($me:expr) => { + $me.make_expr().map(|e| smallvec![ast::Stmt { + id: ast::DUMMY_NODE_ID, + span: e.span, + kind: ast::StmtKind::Expr(e), + }]) + } +} + +/// The result of a macro expansion. The return values of the various +/// methods are spliced into the AST at the callsite of the macro. +pub trait MacResult { + /// Creates an expression. + fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> { + None + } + /// Creates zero or more items. + fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> { + None + } + + /// Creates zero or more impl items. + fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> { + None + } + + /// Creates zero or more trait items. + fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> { + None + } + + /// Creates zero or more items in an `extern {}` block + fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> { None } + + /// Creates a pattern. + fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> { + None + } + + /// Creates zero or more statements. + /// + /// By default this attempts to create an expression statement, + /// returning None if that fails. + fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> { + make_stmts_default!(self) + } + + fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> { + None + } + + fn make_arms(self: Box<Self>) -> Option<SmallVec<[ast::Arm; 1]>> { + None + } + + fn make_fields(self: Box<Self>) -> Option<SmallVec<[ast::Field; 1]>> { + None + } + + fn make_field_patterns(self: Box<Self>) -> Option<SmallVec<[ast::FieldPat; 1]>> { + None + } + + fn make_generic_params(self: Box<Self>) -> Option<SmallVec<[ast::GenericParam; 1]>> { + None + } + + fn make_params(self: Box<Self>) -> Option<SmallVec<[ast::Param; 1]>> { + None + } + + fn make_struct_fields(self: Box<Self>) -> Option<SmallVec<[ast::StructField; 1]>> { + None + } + + fn make_variants(self: Box<Self>) -> Option<SmallVec<[ast::Variant; 1]>> { + None + } +} + +macro_rules! make_MacEager { + ( $( $fld:ident: $t:ty, )* ) => { + /// `MacResult` implementation for the common case where you've already + /// built each form of AST that you might return. + #[derive(Default)] + pub struct MacEager { + $( + pub $fld: Option<$t>, + )* + } + + impl MacEager { + $( + pub fn $fld(v: $t) -> Box<dyn MacResult> { + Box::new(MacEager { + $fld: Some(v), + ..Default::default() + }) + } + )* + } + } +} + +make_MacEager! { + expr: P<ast::Expr>, + pat: P<ast::Pat>, + items: SmallVec<[P<ast::Item>; 1]>, + impl_items: SmallVec<[ast::ImplItem; 1]>, + trait_items: SmallVec<[ast::TraitItem; 1]>, + foreign_items: SmallVec<[ast::ForeignItem; 1]>, + stmts: SmallVec<[ast::Stmt; 1]>, + ty: P<ast::Ty>, +} + +impl MacResult for MacEager { + fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> { + self.expr + } + + fn make_items(self: Box<Self>) -> Option<SmallVec<[P<ast::Item>; 1]>> { + self.items + } + + fn make_impl_items(self: Box<Self>) -> Option<SmallVec<[ast::ImplItem; 1]>> { + self.impl_items + } + + fn make_trait_items(self: Box<Self>) -> Option<SmallVec<[ast::TraitItem; 1]>> { + self.trait_items + } + + fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> { + self.foreign_items + } + + fn make_stmts(self: Box<Self>) -> Option<SmallVec<[ast::Stmt; 1]>> { + match self.stmts.as_ref().map_or(0, |s| s.len()) { + 0 => make_stmts_default!(self), + _ => self.stmts, + } + } + + fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> { + if let Some(p) = self.pat { + return Some(p); + } + if let Some(e) = self.expr { + if let ast::ExprKind::Lit(_) = e.kind { + return Some(P(ast::Pat { + id: ast::DUMMY_NODE_ID, + span: e.span, + kind: PatKind::Lit(e), + })); + } + } + None + } + + fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> { + self.ty + } +} + +/// Fill-in macro expansion result, to allow compilation to continue +/// after hitting errors. +#[derive(Copy, Clone)] +pub struct DummyResult { + is_error: bool, + span: Span, +} + +impl DummyResult { + /// Creates a default MacResult that can be anything. + /// + /// Use this as a return value after hitting any errors and + /// calling `span_err`. + pub fn any(span: Span) -> Box<dyn MacResult+'static> { + Box::new(DummyResult { is_error: true, span }) + } + + /// Same as `any`, but must be a valid fragment, not error. + pub fn any_valid(span: Span) -> Box<dyn MacResult+'static> { + Box::new(DummyResult { is_error: false, span }) + } + + /// A plain dummy expression. + pub fn raw_expr(sp: Span, is_error: bool) -> P<ast::Expr> { + P(ast::Expr { + id: ast::DUMMY_NODE_ID, + kind: if is_error { ast::ExprKind::Err } else { ast::ExprKind::Tup(Vec::new()) }, + span: sp, + attrs: ThinVec::new(), + }) + } + + /// A plain dummy pattern. + pub fn raw_pat(sp: Span) -> ast::Pat { + ast::Pat { + id: ast::DUMMY_NODE_ID, + kind: PatKind::Wild, + span: sp, + } + } + + /// A plain dummy type. + pub fn raw_ty(sp: Span, is_error: bool) -> P<ast::Ty> { + P(ast::Ty { + id: ast::DUMMY_NODE_ID, + kind: if is_error { ast::TyKind::Err } else { ast::TyKind::Tup(Vec::new()) }, + span: sp + }) + } +} + +impl MacResult for DummyResult { + fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> { + Some(DummyResult::raw_expr(self.span, self.is_error)) + } + + fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> { + Some(P(DummyResult::raw_pat(self.span))) + } + + fn make_items(self: Box<DummyResult>) -> Option<SmallVec<[P<ast::Item>; 1]>> { + Some(SmallVec::new()) + } + + fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::ImplItem; 1]>> { + Some(SmallVec::new()) + } + + fn make_trait_items(self: Box<DummyResult>) -> Option<SmallVec<[ast::TraitItem; 1]>> { + Some(SmallVec::new()) + } + + fn make_foreign_items(self: Box<Self>) -> Option<SmallVec<[ast::ForeignItem; 1]>> { + Some(SmallVec::new()) + } + + fn make_stmts(self: Box<DummyResult>) -> Option<SmallVec<[ast::Stmt; 1]>> { + Some(smallvec![ast::Stmt { + id: ast::DUMMY_NODE_ID, + kind: ast::StmtKind::Expr(DummyResult::raw_expr(self.span, self.is_error)), + span: self.span, + }]) + } + + fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> { + Some(DummyResult::raw_ty(self.span, self.is_error)) + } + + fn make_arms(self: Box<DummyResult>) -> Option<SmallVec<[ast::Arm; 1]>> { + Some(SmallVec::new()) + } + + fn make_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::Field; 1]>> { + Some(SmallVec::new()) + } + + fn make_field_patterns(self: Box<DummyResult>) -> Option<SmallVec<[ast::FieldPat; 1]>> { + Some(SmallVec::new()) + } + + fn make_generic_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::GenericParam; 1]>> { + Some(SmallVec::new()) + } + + fn make_params(self: Box<DummyResult>) -> Option<SmallVec<[ast::Param; 1]>> { + Some(SmallVec::new()) + } + + fn make_struct_fields(self: Box<DummyResult>) -> Option<SmallVec<[ast::StructField; 1]>> { + Some(SmallVec::new()) + } + + fn make_variants(self: Box<DummyResult>) -> Option<SmallVec<[ast::Variant; 1]>> { + Some(SmallVec::new()) + } +} + +/// A syntax extension kind. +pub enum SyntaxExtensionKind { + /// A token-based function-like macro. + Bang( + /// An expander with signature TokenStream -> TokenStream. + Box<dyn ProcMacro + sync::Sync + sync::Send>, + ), + + /// An AST-based function-like macro. + LegacyBang( + /// An expander with signature TokenStream -> AST. + Box<dyn TTMacroExpander + sync::Sync + sync::Send>, + ), + + /// A token-based attribute macro. + Attr( + /// An expander with signature (TokenStream, TokenStream) -> TokenStream. + /// The first TokenSteam is the attribute itself, the second is the annotated item. + /// The produced TokenSteam replaces the input TokenSteam. + Box<dyn AttrProcMacro + sync::Sync + sync::Send>, + ), + + /// An AST-based attribute macro. + LegacyAttr( + /// An expander with signature (AST, AST) -> AST. + /// The first AST fragment is the attribute itself, the second is the annotated item. + /// The produced AST fragment replaces the input AST fragment. + Box<dyn MultiItemModifier + sync::Sync + sync::Send>, + ), + + /// A trivial attribute "macro" that does nothing, + /// only keeps the attribute and marks it as inert, + /// thus making it ineligible for further expansion. + NonMacroAttr { + /// Suppresses the `unused_attributes` lint for this attribute. + mark_used: bool, + }, + + /// A token-based derive macro. + Derive( + /// An expander with signature TokenStream -> TokenStream (not yet). + /// The produced TokenSteam is appended to the input TokenSteam. + Box<dyn MultiItemModifier + sync::Sync + sync::Send>, + ), + + /// An AST-based derive macro. + LegacyDerive( + /// An expander with signature AST -> AST. + /// The produced AST fragment is appended to the input AST fragment. + Box<dyn MultiItemModifier + sync::Sync + sync::Send>, + ), +} + +/// A struct representing a macro definition in "lowered" form ready for expansion. +pub struct SyntaxExtension { + /// A syntax extension kind. + pub kind: SyntaxExtensionKind, + /// Span of the macro definition. + pub span: Span, + /// Whitelist of unstable features that are treated as stable inside this macro. + pub allow_internal_unstable: Option<Lrc<[Symbol]>>, + /// Suppresses the `unsafe_code` lint for code produced by this macro. + pub allow_internal_unsafe: bool, + /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro. + pub local_inner_macros: bool, + /// The macro's stability info. + pub stability: Option<Stability>, + /// The macro's deprecation info. + pub deprecation: Option<Deprecation>, + /// Names of helper attributes registered by this macro. + pub helper_attrs: Vec<Symbol>, + /// Edition of the crate in which this macro is defined. + pub edition: Edition, + /// Built-in macros have a couple of special properties like availability + /// in `#[no_implicit_prelude]` modules, so we have to keep this flag. + pub is_builtin: bool, + /// We have to identify macros providing a `Copy` impl early for compatibility reasons. + pub is_derive_copy: bool, +} + +impl SyntaxExtension { + /// Returns which kind of macro calls this syntax extension. + pub fn macro_kind(&self) -> MacroKind { + match self.kind { + SyntaxExtensionKind::Bang(..) | + SyntaxExtensionKind::LegacyBang(..) => MacroKind::Bang, + SyntaxExtensionKind::Attr(..) | + SyntaxExtensionKind::LegacyAttr(..) | + SyntaxExtensionKind::NonMacroAttr { .. } => MacroKind::Attr, + SyntaxExtensionKind::Derive(..) | + SyntaxExtensionKind::LegacyDerive(..) => MacroKind::Derive, + } + } + + /// Constructs a syntax extension with default properties. + pub fn default(kind: SyntaxExtensionKind, edition: Edition) -> SyntaxExtension { + SyntaxExtension { + span: DUMMY_SP, + allow_internal_unstable: None, + allow_internal_unsafe: false, + local_inner_macros: false, + stability: None, + deprecation: None, + helper_attrs: Vec::new(), + edition, + is_builtin: false, + is_derive_copy: false, + kind, + } + } + + /// Constructs a syntax extension with the given properties + /// and other properties converted from attributes. + pub fn new( + sess: &ParseSess, + kind: SyntaxExtensionKind, + span: Span, + helper_attrs: Vec<Symbol>, + edition: Edition, + name: Name, + attrs: &[ast::Attribute], + ) -> SyntaxExtension { + let allow_internal_unstable = attr::allow_internal_unstable( + &attrs, &sess.span_diagnostic, + ).map(|features| features.collect::<Vec<Symbol>>().into()); + + let mut local_inner_macros = false; + if let Some(macro_export) = attr::find_by_name(attrs, sym::macro_export) { + if let Some(l) = macro_export.meta_item_list() { + local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros); + } + } + + let is_builtin = attr::contains_name(attrs, sym::rustc_builtin_macro); + + SyntaxExtension { + kind, + span, + allow_internal_unstable, + allow_internal_unsafe: attr::contains_name(attrs, sym::allow_internal_unsafe), + local_inner_macros, + stability: attr::find_stability(&sess, attrs, span), + deprecation: attr::find_deprecation(&sess, attrs, span), + helper_attrs, + edition, + is_builtin, + is_derive_copy: is_builtin && name == sym::Copy, + } + } + + pub fn dummy_bang(edition: Edition) -> SyntaxExtension { + fn expander<'cx>(_: &'cx mut ExtCtxt<'_>, span: Span, _: TokenStream) + -> Box<dyn MacResult + 'cx> { + DummyResult::any(span) + } + SyntaxExtension::default(SyntaxExtensionKind::LegacyBang(Box::new(expander)), edition) + } + + pub fn dummy_derive(edition: Edition) -> SyntaxExtension { + fn expander(_: &mut ExtCtxt<'_>, _: Span, _: &ast::MetaItem, _: Annotatable) + -> Vec<Annotatable> { + Vec::new() + } + SyntaxExtension::default(SyntaxExtensionKind::Derive(Box::new(expander)), edition) + } + + pub fn non_macro_attr(mark_used: bool, edition: Edition) -> SyntaxExtension { + SyntaxExtension::default(SyntaxExtensionKind::NonMacroAttr { mark_used }, edition) + } + + pub fn expn_data(&self, parent: ExpnId, call_site: Span, descr: Symbol) -> ExpnData { + ExpnData { + kind: ExpnKind::Macro(self.macro_kind(), descr), + parent, + call_site, + def_site: self.span, + allow_internal_unstable: self.allow_internal_unstable.clone(), + allow_internal_unsafe: self.allow_internal_unsafe, + local_inner_macros: self.local_inner_macros, + edition: self.edition, + } + } +} + +pub type NamedSyntaxExtension = (Name, SyntaxExtension); + +/// Result of resolving a macro invocation. +pub enum InvocationRes { + Single(Lrc<SyntaxExtension>), + DeriveContainer(Vec<Lrc<SyntaxExtension>>), +} + +/// Error type that denotes indeterminacy. +pub struct Indeterminate; + +bitflags::bitflags! { + /// Built-in derives that need some extra tracking beyond the usual macro functionality. + #[derive(Default)] + pub struct SpecialDerives: u8 { + const PARTIAL_EQ = 1 << 0; + const EQ = 1 << 1; + const COPY = 1 << 2; + } +} + +pub trait Resolver { + fn next_node_id(&mut self) -> NodeId; + + fn resolve_dollar_crates(&mut self); + fn visit_ast_fragment_with_placeholders(&mut self, expn_id: ExpnId, fragment: &AstFragment, + extra_placeholders: &[NodeId]); + fn register_builtin_macro(&mut self, ident: ast::Ident, ext: SyntaxExtension); + + fn expansion_for_ast_pass( + &mut self, + call_site: Span, + pass: AstPass, + features: &[Symbol], + parent_module_id: Option<NodeId>, + ) -> ExpnId; + + fn resolve_imports(&mut self); + + fn resolve_macro_invocation( + &mut self, invoc: &Invocation, eager_expansion_root: ExpnId, force: bool + ) -> Result<InvocationRes, Indeterminate>; + + fn check_unused_macros(&self); + + fn has_derives(&self, expn_id: ExpnId, derives: SpecialDerives) -> bool; + fn add_derives(&mut self, expn_id: ExpnId, derives: SpecialDerives); +} + +#[derive(Clone)] +pub struct ModuleData { + pub mod_path: Vec<ast::Ident>, + pub directory: PathBuf, +} + +#[derive(Clone)] +pub struct ExpansionData { + pub id: ExpnId, + pub depth: usize, + pub module: Rc<ModuleData>, + pub directory_ownership: DirectoryOwnership, + pub prior_type_ascription: Option<(Span, bool)>, +} + +/// One of these is made during expansion and incrementally updated as we go; +/// when a macro expansion occurs, the resulting nodes have the `backtrace() +/// -> expn_data` of their expansion context stored into their span. +pub struct ExtCtxt<'a> { + pub parse_sess: &'a ParseSess, + pub ecfg: expand::ExpansionConfig<'a>, + pub root_path: PathBuf, + pub resolver: &'a mut dyn Resolver, + pub current_expansion: ExpansionData, + pub expansions: FxHashMap<Span, Vec<String>>, +} + +impl<'a> ExtCtxt<'a> { + pub fn new(parse_sess: &'a ParseSess, + ecfg: expand::ExpansionConfig<'a>, + resolver: &'a mut dyn Resolver) + -> ExtCtxt<'a> { + ExtCtxt { + parse_sess, + ecfg, + root_path: PathBuf::new(), + resolver, + current_expansion: ExpansionData { + id: ExpnId::root(), + depth: 0, + module: Rc::new(ModuleData { mod_path: Vec::new(), directory: PathBuf::new() }), + directory_ownership: DirectoryOwnership::Owned { relative: None }, + prior_type_ascription: None, + }, + expansions: FxHashMap::default(), + } + } + + /// Returns a `Folder` for deeply expanding all macros in an AST node. + pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> { + expand::MacroExpander::new(self, false) + } + + /// Returns a `Folder` that deeply expands all macros and assigns all `NodeId`s in an AST node. + /// Once `NodeId`s are assigned, the node may not be expanded, removed, or otherwise modified. + pub fn monotonic_expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> { + expand::MacroExpander::new(self, true) + } + pub fn new_parser_from_tts(&self, stream: TokenStream) -> parser::Parser<'a> { + parse::stream_to_parser(self.parse_sess, stream, MACRO_ARGUMENTS) + } + pub fn source_map(&self) -> &'a SourceMap { self.parse_sess.source_map() } + pub fn parse_sess(&self) -> &'a ParseSess { self.parse_sess } + pub fn cfg(&self) -> &ast::CrateConfig { &self.parse_sess.config } + pub fn call_site(&self) -> Span { + self.current_expansion.id.expn_data().call_site + } + + /// Equivalent of `Span::def_site` from the proc macro API, + /// except that the location is taken from the span passed as an argument. + pub fn with_def_site_ctxt(&self, span: Span) -> Span { + span.with_def_site_ctxt(self.current_expansion.id) + } + + /// Equivalent of `Span::call_site` from the proc macro API, + /// except that the location is taken from the span passed as an argument. + pub fn with_call_site_ctxt(&self, span: Span) -> Span { + span.with_call_site_ctxt(self.current_expansion.id) + } + + /// Equivalent of `Span::mixed_site` from the proc macro API, + /// except that the location is taken from the span passed as an argument. + pub fn with_mixed_site_ctxt(&self, span: Span) -> Span { + span.with_mixed_site_ctxt(self.current_expansion.id) + } + + /// Returns span for the macro which originally caused the current expansion to happen. + /// + /// Stops backtracing at include! boundary. + pub fn expansion_cause(&self) -> Option<Span> { + let mut expn_id = self.current_expansion.id; + let mut last_macro = None; + loop { + let expn_data = expn_id.expn_data(); + // Stop going up the backtrace once include! is encountered + if expn_data.is_root() || expn_data.kind.descr() == sym::include { + break; + } + expn_id = expn_data.call_site.ctxt().outer_expn(); + last_macro = Some(expn_data.call_site); + } + last_macro + } + + pub fn struct_span_warn<S: Into<MultiSpan>>(&self, + sp: S, + msg: &str) + -> DiagnosticBuilder<'a> { + self.parse_sess.span_diagnostic.struct_span_warn(sp, msg) + } + pub fn struct_span_err<S: Into<MultiSpan>>(&self, + sp: S, + msg: &str) + -> DiagnosticBuilder<'a> { + self.parse_sess.span_diagnostic.struct_span_err(sp, msg) + } + pub fn struct_span_fatal<S: Into<MultiSpan>>(&self, + sp: S, + msg: &str) + -> DiagnosticBuilder<'a> { + self.parse_sess.span_diagnostic.struct_span_fatal(sp, msg) + } + + /// Emit `msg` attached to `sp`, and stop compilation immediately. + /// + /// `span_err` should be strongly preferred where-ever possible: + /// this should *only* be used when: + /// + /// - continuing has a high risk of flow-on errors (e.g., errors in + /// declaring a macro would cause all uses of that macro to + /// complain about "undefined macro"), or + /// - there is literally nothing else that can be done (however, + /// in most cases one can construct a dummy expression/item to + /// substitute; we never hit resolve/type-checking so the dummy + /// value doesn't have to match anything) + pub fn span_fatal<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! { + self.parse_sess.span_diagnostic.span_fatal(sp, msg).raise(); + } + + /// Emit `msg` attached to `sp`, without immediately stopping + /// compilation. + /// + /// Compilation will be stopped in the near future (at the end of + /// the macro expansion phase). + pub fn span_err<S: Into<MultiSpan>>(&self, sp: S, msg: &str) { + self.parse_sess.span_diagnostic.span_err(sp, msg); + } + pub fn span_err_with_code<S: Into<MultiSpan>>(&self, sp: S, msg: &str, code: DiagnosticId) { + self.parse_sess.span_diagnostic.span_err_with_code(sp, msg, code); + } + pub fn span_warn<S: Into<MultiSpan>>(&self, sp: S, msg: &str) { + self.parse_sess.span_diagnostic.span_warn(sp, msg); + } + pub fn span_bug<S: Into<MultiSpan>>(&self, sp: S, msg: &str) -> ! { + self.parse_sess.span_diagnostic.span_bug(sp, msg); + } + pub fn trace_macros_diag(&mut self) { + for (sp, notes) in self.expansions.iter() { + let mut db = self.parse_sess.span_diagnostic.span_note_diag(*sp, "trace_macro"); + for note in notes { + db.note(note); + } + db.emit(); + } + // Fixme: does this result in errors? + self.expansions.clear(); + } + pub fn bug(&self, msg: &str) -> ! { + self.parse_sess.span_diagnostic.bug(msg); + } + pub fn trace_macros(&self) -> bool { + self.ecfg.trace_mac + } + pub fn set_trace_macros(&mut self, x: bool) { + self.ecfg.trace_mac = x + } + pub fn ident_of(&self, st: &str, sp: Span) -> ast::Ident { + ast::Ident::from_str_and_span(st, sp) + } + pub fn std_path(&self, components: &[Symbol]) -> Vec<ast::Ident> { + let def_site = self.with_def_site_ctxt(DUMMY_SP); + iter::once(Ident::new(kw::DollarCrate, def_site)) + .chain(components.iter().map(|&s| Ident::with_dummy_span(s))) + .collect() + } + pub fn name_of(&self, st: &str) -> ast::Name { + Symbol::intern(st) + } + + pub fn check_unused_macros(&self) { + self.resolver.check_unused_macros(); + } + + /// Resolves a path mentioned inside Rust code. + /// + /// This unifies the logic used for resolving `include_X!`, and `#[doc(include)]` file paths. + /// + /// Returns an absolute path to the file that `path` refers to. + pub fn resolve_path(&self, path: impl Into<PathBuf>, span: Span) -> PathBuf { + let path = path.into(); + + // Relative paths are resolved relative to the file in which they are found + // after macro expansion (that is, they are unhygienic). + if !path.is_absolute() { + let callsite = span.source_callsite(); + let mut result = match self.source_map().span_to_unmapped_path(callsite) { + FileName::Real(path) => path, + FileName::DocTest(path, _) => path, + other => panic!("cannot resolve relative path in non-file source `{}`", other), + }; + result.pop(); + result.push(path); + result + } else { + path + } + } +} + +/// Extracts a string literal from the macro expanded version of `expr`, +/// emitting `err_msg` if `expr` is not a string literal. This does not stop +/// compilation on error, merely emits a non-fatal error and returns `None`. +pub fn expr_to_spanned_string<'a>( + cx: &'a mut ExtCtxt<'_>, + expr: P<ast::Expr>, + err_msg: &str, +) -> Result<(Symbol, ast::StrStyle, Span), Option<DiagnosticBuilder<'a>>> { + // Perform eager expansion on the expression. + // We want to be able to handle e.g., `concat!("foo", "bar")`. + let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr(); + + Err(match expr.kind { + ast::ExprKind::Lit(ref l) => match l.kind { + ast::LitKind::Str(s, style) => return Ok((s, style, expr.span)), + ast::LitKind::Err(_) => None, + _ => Some(cx.struct_span_err(l.span, err_msg)) + }, + ast::ExprKind::Err => None, + _ => Some(cx.struct_span_err(expr.span, err_msg)) + }) +} + +pub fn expr_to_string(cx: &mut ExtCtxt<'_>, expr: P<ast::Expr>, err_msg: &str) + -> Option<(Symbol, ast::StrStyle)> { + expr_to_spanned_string(cx, expr, err_msg) + .map_err(|err| err.map(|mut err| err.emit())) + .ok() + .map(|(symbol, style, _)| (symbol, style)) +} + +/// Non-fatally assert that `tts` is empty. Note that this function +/// returns even when `tts` is non-empty, macros that *need* to stop +/// compilation should call +/// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be +/// done as rarely as possible). +pub fn check_zero_tts(cx: &ExtCtxt<'_>, + sp: Span, + tts: TokenStream, + name: &str) { + if !tts.is_empty() { + cx.span_err(sp, &format!("{} takes no arguments", name)); + } +} + +/// Interpreting `tts` as a comma-separated sequence of expressions, +/// expect exactly one string literal, or emit an error and return `None`. +pub fn get_single_str_from_tts(cx: &mut ExtCtxt<'_>, + sp: Span, + tts: TokenStream, + name: &str) + -> Option<String> { + let mut p = cx.new_parser_from_tts(tts); + if p.token == token::Eof { + cx.span_err(sp, &format!("{} takes 1 argument", name)); + return None + } + let ret = panictry!(p.parse_expr()); + let _ = p.eat(&token::Comma); + + if p.token != token::Eof { + cx.span_err(sp, &format!("{} takes 1 argument", name)); + } + expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| { + s.to_string() + }) +} + +/// Extracts comma-separated expressions from `tts`. If there is a +/// parsing error, emit a non-fatal error and return `None`. +pub fn get_exprs_from_tts(cx: &mut ExtCtxt<'_>, + sp: Span, + tts: TokenStream) -> Option<Vec<P<ast::Expr>>> { + let mut p = cx.new_parser_from_tts(tts); + let mut es = Vec::new(); + while p.token != token::Eof { + let expr = panictry!(p.parse_expr()); + + // Perform eager expansion on the expression. + // We want to be able to handle e.g., `concat!("foo", "bar")`. + let expr = cx.expander().fully_expand_fragment(AstFragment::Expr(expr)).make_expr(); + + es.push(expr); + if p.eat(&token::Comma) { + continue; + } + if p.token != token::Eof { + cx.span_err(sp, "expected token: `,`"); + return None; + } + } + Some(es) +} |