Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 259 insertions, 65 deletions

diff --git a/compiler/rustc_macros/Cargo.toml b/compiler/rustc_macros/Cargo.toml
index 17651ce95..d8d2bef49 100644
--- a/compiler/rustc_macros/Cargo.toml
+++ b/compiler/rustc_macros/Cargo.toml
@@ -1,13 +1,15 @@
 [package]
 name = "rustc_macros"
-version = "0.1.0"
+version = "0.0.0"
 edition = "2021"
 
 [lib]
 proc-macro = true
 
 [dependencies]
-synstructure = "0.13.0"
-syn = { version = "2.0.9", features = ["full"] }
+# tidy-alphabetical-start
 proc-macro2 = "1"
 quote = "1"
+syn = { version = "2.0.9", features = ["full"] }
+synstructure = "0.13.0"
+# tidy-alphabetical-end
diff --git a/compiler/rustc_macros/src/current_version.rs b/compiler/rustc_macros/src/current_version.rs
new file mode 100644
index 000000000..5e3b91c17
--- /dev/null
+++ b/compiler/rustc_macros/src/current_version.rs
@@ -0,0 +1,59 @@
+use proc_macro::TokenStream;
+use proc_macro2::Span;
+use quote::quote;
+use syn::parse::{Parse, ParseStream};
+use syn::{parenthesized, parse_macro_input, LitStr, Token};
+
+pub struct Input {
+    variable: LitStr,
+}
+
+mod kw {
+    syn::custom_keyword!(env);
+}
+
+impl Parse for Input {
+    // Input syntax is `env!("CFG_RELEASE")` to facilitate grepping.
+    fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
+        let paren;
+        input.parse::<kw::env>()?;
+        input.parse::<Token![!]>()?;
+        parenthesized!(paren in input);
+        let variable: LitStr = paren.parse()?;
+        Ok(Input { variable })
+    }
+}
+
+pub(crate) fn current_version(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as Input);
+
+    TokenStream::from(match RustcVersion::parse_env_var(&input.variable) {
+        Ok(RustcVersion { major, minor, patch }) => quote!(
+            Self { major: #major, minor: #minor, patch: #patch }
+        ),
+        Err(err) => syn::Error::new(Span::call_site(), err).into_compile_error(),
+    })
+}
+
+struct RustcVersion {
+    major: u16,
+    minor: u16,
+    patch: u16,
+}
+
+impl RustcVersion {
+    fn parse_env_var(env_var: &LitStr) -> Result<Self, Box<dyn std::error::Error>> {
+        let value = proc_macro::tracked_env::var(env_var.value())?;
+        Self::parse_str(&value)
+            .ok_or_else(|| format!("failed to parse rustc version: {:?}", value).into())
+    }
+
+    fn parse_str(value: &str) -> Option<Self> {
+        // Ignore any suffixes such as "-dev" or "-nightly".
+        let mut components = value.split('-').next().unwrap().splitn(3, '.');
+        let major = components.next()?.parse().ok()?;
+        let minor = components.next()?.parse().ok()?;
+        let patch = components.next().unwrap_or("0").parse().ok()?;
+        Some(RustcVersion { major, minor, patch })
+    }
+}
diff --git a/compiler/rustc_macros/src/diagnostics/diagnostic.rs b/compiler/rustc_macros/src/diagnostics/diagnostic.rs
index 04b7c5fee..1a8174bfd 100644
--- a/compiler/rustc_macros/src/diagnostics/diagnostic.rs
+++ b/compiler/rustc_macros/src/diagnostics/diagnostic.rs
@@ -42,19 +42,20 @@ impl<'a> DiagnosticDerive<'a> {
             let init = match builder.slug.value_ref() {
                 None => {
                     span_err(builder.span, "diagnostic slug not specified")
-                        .help("specify the slug as the first argument to the `#[diag(...)]` \
-                            attribute, such as `#[diag(hir_analysis_example_error)]`")
+                        .help(
+                            "specify the slug as the first argument to the `#[diag(...)]` \
+                            attribute, such as `#[diag(hir_analysis_example_error)]`",
+                        )
                         .emit();
                     return DiagnosticDeriveError::ErrorHandled.to_compile_error();
                 }
-                Some(slug) if let Some( Mismatch { slug_name, crate_name, slug_prefix }) = Mismatch::check(slug) => {
+                Some(slug)
+                    if let Some(Mismatch { slug_name, crate_name, slug_prefix }) =
+                        Mismatch::check(slug) =>
+                {
                     span_err(slug.span().unwrap(), "diagnostic slug and crate name do not match")
-                        .note(format!(
-                            "slug is `{slug_name}` but the crate name is `{crate_name}`"
-                        ))
-                        .help(format!(
-                            "expected a slug starting with `{slug_prefix}_...`"
-                        ))
+                        .note(format!("slug is `{slug_name}` but the crate name is `{crate_name}`"))
+                        .help(format!("expected a slug starting with `{slug_prefix}_...`"))
                         .emit();
                     return DiagnosticDeriveError::ErrorHandled.to_compile_error();
                 }
@@ -141,19 +142,20 @@ impl<'a> LintDiagnosticDerive<'a> {
             match builder.slug.value_ref() {
                 None => {
                     span_err(builder.span, "diagnostic slug not specified")
-                        .help("specify the slug as the first argument to the attribute, such as \
-                            `#[diag(compiletest_example)]`")
+                        .help(
+                            "specify the slug as the first argument to the attribute, such as \
+                            `#[diag(compiletest_example)]`",
+                        )
                         .emit();
                     DiagnosticDeriveError::ErrorHandled.to_compile_error()
                 }
-                Some(slug) if let Some( Mismatch { slug_name, crate_name, slug_prefix }) = Mismatch::check(slug) => {
+                Some(slug)
+                    if let Some(Mismatch { slug_name, crate_name, slug_prefix }) =
+                        Mismatch::check(slug) =>
+                {
                     span_err(slug.span().unwrap(), "diagnostic slug and crate name do not match")
-                        .note(format!(
-                            "slug is `{slug_name}` but the crate name is `{crate_name}`"
-                        ))
-                        .help(format!(
-                            "expected a slug starting with `{slug_prefix}_...`"
-                        ))
+                        .note(format!("slug is `{slug_name}` but the crate name is `{crate_name}`"))
+                        .help(format!("expected a slug starting with `{slug_prefix}_...`"))
                         .emit();
                     DiagnosticDeriveError::ErrorHandled.to_compile_error()
                 }
diff --git a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
index 877e97450..877271ff0 100644
--- a/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
+++ b/compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
@@ -577,7 +577,9 @@ impl<'parent, 'a> SubdiagnosticDeriveVariantBuilder<'parent, 'a> {
                     }
                 }
                 _ => {
-                    if let Some(span) = span_field && !no_span {
+                    if let Some(span) = span_field
+                        && !no_span
+                    {
                         quote! { #diag.#name(#span, #message); }
                     } else {
                         quote! { #diag.#name(#message); }
diff --git a/compiler/rustc_macros/src/lib.rs b/compiler/rustc_macros/src/lib.rs
index 85829906f..193dbd75f 100644
--- a/compiler/rustc_macros/src/lib.rs
+++ b/compiler/rustc_macros/src/lib.rs
@@ -4,6 +4,7 @@
 #![feature(never_type)]
 #![feature(proc_macro_diagnostic)]
 #![feature(proc_macro_span)]
+#![feature(proc_macro_tracked_env)]
 #![allow(rustc::default_hash_types)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
@@ -14,6 +15,7 @@ use synstructure::decl_derive;
 
 use proc_macro::TokenStream;
 
+mod current_version;
 mod diagnostics;
 mod hash_stable;
 mod lift;
@@ -25,6 +27,11 @@ mod type_foldable;
 mod type_visitable;
 
 #[proc_macro]
+pub fn current_rustc_version(input: TokenStream) -> TokenStream {
+    current_version::current_version(input)
+}
+
+#[proc_macro]
 pub fn rustc_queries(input: TokenStream) -> TokenStream {
     query::rustc_queries(input)
 }
diff --git a/compiler/rustc_macros/src/query.rs b/compiler/rustc_macros/src/query.rs
index d0d41c614..ad1980136 100644
--- a/compiler/rustc_macros/src/query.rs
+++ b/compiler/rustc_macros/src/query.rs
@@ -97,6 +97,9 @@ struct QueryModifiers {
     /// A cycle error results in a delay_bug call
     cycle_delay_bug: Option<Ident>,
 
+    /// A cycle error results in a stashed cycle error that can be unstashed and canceled later
+    cycle_stash: Option<Ident>,
+
     /// Don't hash the result, instead just mark a query red if it runs
     no_hash: Option<Ident>,
 
@@ -114,6 +117,11 @@ struct QueryModifiers {
 
     /// Generate a `feed` method to set the query's value from another query.
     feedable: Option<Ident>,
+
+    /// Forward the result on ensure if the query gets recomputed, and
+    /// return `Ok(())` otherwise. Only applicable to queries returning
+    /// `Result<(), ErrorGuaranteed>`
+    ensure_forwards_result_if_red: Option<Ident>,
 }
 
 fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
@@ -122,12 +130,14 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
     let mut desc = None;
     let mut fatal_cycle = None;
     let mut cycle_delay_bug = None;
+    let mut cycle_stash = None;
     let mut no_hash = None;
     let mut anon = None;
     let mut eval_always = None;
     let mut depth_limit = None;
     let mut separate_provide_extern = None;
     let mut feedable = None;
+    let mut ensure_forwards_result_if_red = None;
 
     while !input.is_empty() {
         let modifier: Ident = input.parse()?;
@@ -175,6 +185,8 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
             try_insert!(fatal_cycle = modifier);
         } else if modifier == "cycle_delay_bug" {
             try_insert!(cycle_delay_bug = modifier);
+        } else if modifier == "cycle_stash" {
+            try_insert!(cycle_stash = modifier);
         } else if modifier == "no_hash" {
             try_insert!(no_hash = modifier);
         } else if modifier == "anon" {
@@ -187,6 +199,8 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
             try_insert!(separate_provide_extern = modifier);
         } else if modifier == "feedable" {
             try_insert!(feedable = modifier);
+        } else if modifier == "ensure_forwards_result_if_red" {
+            try_insert!(ensure_forwards_result_if_red = modifier);
         } else {
             return Err(Error::new(modifier.span(), "unknown query modifier"));
         }
@@ -200,12 +214,14 @@ fn parse_query_modifiers(input: ParseStream<'_>) -> Result<QueryModifiers> {
         desc,
         fatal_cycle,
         cycle_delay_bug,
+        cycle_stash,
         no_hash,
         anon,
         eval_always,
         depth_limit,
         separate_provide_extern,
         feedable,
+        ensure_forwards_result_if_red,
     })
 }
 
@@ -320,11 +336,13 @@ pub fn rustc_queries(input: TokenStream) -> TokenStream {
             fatal_cycle,
             arena_cache,
             cycle_delay_bug,
+            cycle_stash,
             no_hash,
             anon,
             eval_always,
             depth_limit,
             separate_provide_extern,
+            ensure_forwards_result_if_red,
         );
 
         if modifiers.cache.is_some() {
diff --git a/compiler/rustc_macros/src/serialize.rs b/compiler/rustc_macros/src/serialize.rs
index ba75517d7..047066ac6 100644
--- a/compiler/rustc_macros/src/serialize.rs
+++ b/compiler/rustc_macros/src/serialize.rs
@@ -5,11 +5,16 @@ use syn::spanned::Spanned;
 
 pub fn type_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
     let decoder_ty = quote! { __D };
-    if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
-        s.add_impl_generic(parse_quote! { 'tcx });
-    }
-    s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_type_ir::codec::TyDecoder<I = ::rustc_middle::ty::TyCtxt<'tcx>>});
-    s.add_bounds(synstructure::AddBounds::Generics);
+    let bound = if s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+        quote! { <I = ::rustc_middle::ty::TyCtxt<'tcx>> }
+    } else if s.ast().generics.type_params().any(|ty| ty.ident == "I") {
+        quote! { <I = I> }
+    } else {
+        quote! {}
+    };
+
+    s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_type_ir::codec::TyDecoder #bound });
+    s.add_bounds(synstructure::AddBounds::Fields);
 
     decodable_body(s, decoder_ty)
 }
@@ -97,12 +102,17 @@ fn decode_field(field: &syn::Field) -> proc_macro2::TokenStream {
 }
 
 pub fn type_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream {
-    if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
-        s.add_impl_generic(parse_quote! {'tcx});
-    }
+    let bound = if s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") {
+        quote! { <I = ::rustc_middle::ty::TyCtxt<'tcx>> }
+    } else if s.ast().generics.type_params().any(|ty| ty.ident == "I") {
+        quote! { <I = I> }
+    } else {
+        quote! {}
+    };
+
     let encoder_ty = quote! { __E };
-    s.add_impl_generic(parse_quote! {#encoder_ty: ::rustc_type_ir::codec::TyEncoder<I = ::rustc_middle::ty::TyCtxt<'tcx>>});
-    s.add_bounds(synstructure::AddBounds::Generics);
+    s.add_impl_generic(parse_quote! {#encoder_ty: ::rustc_type_ir::codec::TyEncoder #bound });
+    s.add_bounds(synstructure::AddBounds::Fields);
 
     encodable_body(s, encoder_ty, false)
 }
diff --git a/compiler/rustc_macros/src/symbols.rs b/compiler/rustc_macros/src/symbols.rs
index 04facbf65..4129712a6 100644
--- a/compiler/rustc_macros/src/symbols.rs
+++ b/compiler/rustc_macros/src/symbols.rs
@@ -26,7 +26,7 @@ use proc_macro2::{Span, TokenStream};
 use quote::quote;
 use std::collections::HashMap;
 use syn::parse::{Parse, ParseStream, Result};
-use syn::{braced, punctuated::Punctuated, Ident, LitStr, Token};
+use syn::{braced, punctuated::Punctuated, Expr, Ident, Lit, LitStr, Macro, Token};
 
 #[cfg(test)]
 mod tests;
@@ -53,21 +53,46 @@ impl Parse for Keyword {
 
 struct Symbol {
     name: Ident,
-    value: Option<LitStr>,
+    value: Value,
+}
+
+enum Value {
+    SameAsName,
+    String(LitStr),
+    Env(LitStr, Macro),
+    Unsupported(Expr),
 }
 
 impl Parse for Symbol {
     fn parse(input: ParseStream<'_>) -> Result<Self> {
         let name = input.parse()?;
-        let value = match input.parse::<Token![:]>() {
-            Ok(_) => Some(input.parse()?),
-            Err(_) => None,
-        };
+        let colon_token: Option<Token![:]> = input.parse()?;
+        let value = if colon_token.is_some() { input.parse()? } else { Value::SameAsName };
 
         Ok(Symbol { name, value })
     }
 }
 
+impl Parse for Value {
+    fn parse(input: ParseStream<'_>) -> Result<Self> {
+        let expr: Expr = input.parse()?;
+        match &expr {
+            Expr::Lit(expr) => {
+                if let Lit::Str(lit) = &expr.lit {
+                    return Ok(Value::String(lit.clone()));
+                }
+            }
+            Expr::Macro(expr) => {
+                if expr.mac.path.is_ident("env") && let Ok(lit) = expr.mac.parse_body() {
+                    return Ok(Value::Env(lit, expr.mac.clone()));
+                }
+            }
+            _ => {}
+        }
+        Ok(Value::Unsupported(expr))
+    }
+}
+
 struct Input {
     keywords: Punctuated<Keyword, Token![,]>,
     symbols: Punctuated<Symbol, Token![,]>,
@@ -111,6 +136,37 @@ pub fn symbols(input: TokenStream) -> TokenStream {
     output
 }
 
+struct Preinterned {
+    idx: u32,
+    span_of_name: Span,
+}
+
+struct Entries {
+    map: HashMap<String, Preinterned>,
+}
+
+impl Entries {
+    fn with_capacity(capacity: usize) -> Self {
+        Entries { map: HashMap::with_capacity(capacity) }
+    }
+
+    fn insert(&mut self, span: Span, str: &str, errors: &mut Errors) -> u32 {
+        if let Some(prev) = self.map.get(str) {
+            errors.error(span, format!("Symbol `{str}` is duplicated"));
+            errors.error(prev.span_of_name, "location of previous definition".to_string());
+            prev.idx
+        } else {
+            let idx = self.len();
+            self.map.insert(str.to_string(), Preinterned { idx, span_of_name: span });
+            idx
+        }
+    }
+
+    fn len(&self) -> u32 {
+        u32::try_from(self.map.len()).expect("way too many symbols")
+    }
+}
+
 fn symbols_with_errors(input: TokenStream) -> (TokenStream, Vec<syn::Error>) {
     let mut errors = Errors::default();
 
@@ -127,20 +183,9 @@ fn symbols_with_errors(input: TokenStream) -> (TokenStream, Vec<syn::Error>) {
     let mut keyword_stream = quote! {};
     let mut symbols_stream = quote! {};
     let mut prefill_stream = quote! {};
-    let mut counter = 0u32;
-    let mut keys =
-        HashMap::<String, Span>::with_capacity(input.keywords.len() + input.symbols.len() + 10);
+    let mut entries = Entries::with_capacity(input.keywords.len() + input.symbols.len() + 10);
     let mut prev_key: Option<(Span, String)> = None;
 
-    let mut check_dup = |span: Span, str: &str, errors: &mut Errors| {
-        if let Some(prev_span) = keys.get(str) {
-            errors.error(span, format!("Symbol `{str}` is duplicated"));
-            errors.error(*prev_span, "location of previous definition".to_string());
-        } else {
-            keys.insert(str.to_string(), span);
-        }
-    };
-
     let mut check_order = |span: Span, str: &str, errors: &mut Errors| {
         if let Some((prev_span, ref prev_str)) = prev_key {
             if str < prev_str {
@@ -156,49 +201,98 @@ fn symbols_with_errors(input: TokenStream) -> (TokenStream, Vec<syn::Error>) {
         let name = &keyword.name;
         let value = &keyword.value;
         let value_string = value.value();
-        check_dup(keyword.name.span(), &value_string, &mut errors);
+        let idx = entries.insert(keyword.name.span(), &value_string, &mut errors);
         prefill_stream.extend(quote! {
             #value,
         });
         keyword_stream.extend(quote! {
-            pub const #name: Symbol = Symbol::new(#counter);
+            pub const #name: Symbol = Symbol::new(#idx);
         });
-        counter += 1;
     }
 
     // Generate the listed symbols.
     for symbol in input.symbols.iter() {
         let name = &symbol.name;
+        check_order(symbol.name.span(), &name.to_string(), &mut errors);
+
         let value = match &symbol.value {
-            Some(value) => value.value(),
-            None => name.to_string(),
+            Value::SameAsName => name.to_string(),
+            Value::String(lit) => lit.value(),
+            Value::Env(..) => continue, // in another loop below
+            Value::Unsupported(expr) => {
+                errors.list.push(syn::Error::new_spanned(
+                    expr,
+                    concat!(
+                        "unsupported expression for symbol value; implement support for this in ",
+                        file!(),
+                    ),
+                ));
+                continue;
+            }
         };
-        check_dup(symbol.name.span(), &value, &mut errors);
-        check_order(symbol.name.span(), &name.to_string(), &mut errors);
+        let idx = entries.insert(symbol.name.span(), &value, &mut errors);
 
         prefill_stream.extend(quote! {
             #value,
         });
         symbols_stream.extend(quote! {
-            pub const #name: Symbol = Symbol::new(#counter);
+            pub const #name: Symbol = Symbol::new(#idx);
         });
-        counter += 1;
     }
 
     // Generate symbols for the strings "0", "1", ..., "9".
-    let digits_base = counter;
-    counter += 10;
     for n in 0..10 {
         let n = n.to_string();
-        check_dup(Span::call_site(), &n, &mut errors);
+        entries.insert(Span::call_site(), &n, &mut errors);
         prefill_stream.extend(quote! {
             #n,
         });
     }
 
+    // Symbols whose value comes from an environment variable. It's allowed for
+    // these to have the same value as another symbol.
+    for symbol in &input.symbols {
+        let (env_var, expr) = match &symbol.value {
+            Value::Env(lit, expr) => (lit, expr),
+            Value::SameAsName | Value::String(_) | Value::Unsupported(_) => continue,
+        };
+
+        if !proc_macro::is_available() {
+            errors.error(
+                Span::call_site(),
+                "proc_macro::tracked_env is not available in unit test".to_owned(),
+            );
+            break;
+        }
+
+        let value = match proc_macro::tracked_env::var(env_var.value()) {
+            Ok(value) => value,
+            Err(err) => {
+                errors.list.push(syn::Error::new_spanned(expr, err));
+                continue;
+            }
+        };
+
+        let idx = if let Some(prev) = entries.map.get(&value) {
+            prev.idx
+        } else {
+            prefill_stream.extend(quote! {
+                #value,
+            });
+            entries.insert(symbol.name.span(), &value, &mut errors)
+        };
+
+        let name = &symbol.name;
+        symbols_stream.extend(quote! {
+            pub const #name: Symbol = Symbol::new(#idx);
+        });
+    }
+
+    let symbol_digits_base = entries.map["0"].idx;
+    let preinterned_symbols_count = entries.len();
     let output = quote! {
-        const SYMBOL_DIGITS_BASE: u32 = #digits_base;
-        const PREINTERNED_SYMBOLS_COUNT: u32 = #counter;
+        const SYMBOL_DIGITS_BASE: u32 = #symbol_digits_base;
+        const PREINTERNED_SYMBOLS_COUNT: u32 = #preinterned_symbols_count;
 
         #[doc(hidden)]
         #[allow(non_upper_case_globals)]
diff --git a/compiler/rustc_macros/src/symbols/tests.rs b/compiler/rustc_macros/src/symbols/tests.rs
index bd0c08a53..9c53453df 100644
--- a/compiler/rustc_macros/src/symbols/tests.rs
+++ b/compiler/rustc_macros/src/symbols/tests.rs
@@ -27,7 +27,7 @@ fn test_symbols() {
 
     let body_tokens = m.mac.tokens.clone();
 
-    test_symbols_macro(body_tokens, &[]);
+    test_symbols_macro(body_tokens, &["proc_macro::tracked_env is not available in unit test"]);
 }
 
 fn test_symbols_macro(input: TokenStream, expected_errors: &[&str]) {