Auto merge of #70016 - Dylan-DPC:rollup-5k7lxs3, r=Dylan-DPC

Rollup of 7 pull requests

Successful merges:

 - #69357 (Emit 1-based column numbers in debuginfo)
 - #69471 (Remove `sip::Hasher::short_write`.)
 - #69498 (Change "method" to "associated function")
 - #69967 (Remove a few `Rc`s from RegionInferenceCtxt)
 - #69987 (Add self to .mailmap)
 - #69991 (fix E0117 message out of sync)
 - #69993 (Add long error explanation for E0693)

Failed merges:

r? @ghost

Author: bors

.mailmap

@@ -172,6 +172,9 @@ Mateusz Mikuła <[email protected]> <[email protected]>
 Mateusz Mikuła <[email protected]> <[email protected]>
 Matt Brubeck <[email protected]> <[email protected]>
 Matthew Auld <[email protected]>
+Matthew Kraai <[email protected]>
+Matthew Kraai <[email protected]> <[email protected]>
+Matthew Kraai <[email protected]> <[email protected]>
 Matthew McPherrin <[email protected]> <[email protected]>
 Matthijs Hofstra <[email protected]>
 Melody Horn <[email protected]> <[email protected]>

src/libcore/hash/sip.rs

@@ -220,37 +220,6 @@ impl<S: Sip> Hasher<S> {
         self.state.v3 = self.k1 ^ 0x7465646279746573;
         self.ntail = 0;
     }
-
-    // Specialized write function that is only valid for buffers with len <= 8.
-    // It's used to force inlining of write_u8 and write_usize, those would normally be inlined
-    // except for composite types (that includes slices and str hashing because of delimiter).
-    // Without this extra push the compiler is very reluctant to inline delimiter writes,
-    // degrading performance substantially for the most common use cases.
-    #[inline]
-    fn short_write(&mut self, msg: &[u8]) {
-        debug_assert!(msg.len() <= 8);
-        let length = msg.len();
-        self.length += length;
-
-        let needed = 8 - self.ntail;
-        let fill = cmp::min(length, needed);
-        if fill == 8 {
-            self.tail = unsafe { load_int_le!(msg, 0, u64) };
-        } else {
-            self.tail |= unsafe { u8to64_le(msg, 0, fill) } << (8 * self.ntail);
-            if length < needed {
-                self.ntail += length;
-                return;
-            }
-        }
-        self.state.v3 ^= self.tail;
-        S::c_rounds(&mut self.state);
-        self.state.v0 ^= self.tail;
-
-        // Buffered tail is now flushed, process new input.
-        self.ntail = length - needed;
-        self.tail = unsafe { u8to64_le(msg, needed, self.ntail) };
-    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -280,21 +249,13 @@ impl super::Hasher for SipHasher13 {
 }
 
 impl<S: Sip> super::Hasher for Hasher<S> {
-    // see short_write comment for explanation
-    #[inline]
-    fn write_usize(&mut self, i: usize) {
-        let bytes = unsafe {
-            crate::slice::from_raw_parts(&i as *const usize as *const u8, mem::size_of::<usize>())
-        };
-        self.short_write(bytes);
-    }
-
-    // see short_write comment for explanation
-    #[inline]
-    fn write_u8(&mut self, i: u8) {
-        self.short_write(&[i]);
-    }
-
+    // Note: no integer hashing methods (`write_u*`, `write_i*`) are defined
+    // for this type. We could add them, copy the `short_write` implementation
+    // in librustc_data_structures/sip128.rs, and add `write_u*`/`write_i*`
+    // methods to `SipHasher`, `SipHasher13`, and `DefaultHasher`. This would
+    // greatly speed up integer hashing by those hashers, at the cost of
+    // slightly slowing down compile speeds on some benchmarks. See #69152 for
+    // details.
     #[inline]
     fn write(&mut self, msg: &[u8]) {
         let length = msg.len();

src/librustc_codegen_llvm/debuginfo/create_scope_map.rs

@@ -1,16 +1,12 @@
-use super::metadata::file_metadata;
-use super::utils::{span_start, DIB};
+use super::metadata::{file_metadata, UNKNOWN_COLUMN_NUMBER, UNKNOWN_LINE_NUMBER};
+use super::utils::DIB;
 use rustc_codegen_ssa::mir::debuginfo::{DebugScope, FunctionDebugContext};
 
 use crate::common::CodegenCx;
 use crate::llvm;
 use crate::llvm::debuginfo::{DIScope, DISubprogram};
 use rustc::mir::{Body, SourceScope};
 
-use libc::c_uint;
-
-use rustc_span::Pos;
-
 use rustc_index::bit_set::BitSet;
 use rustc_index::vec::Idx;
 
@@ -54,7 +50,7 @@ fn make_mir_scope(
         debug_context.scopes[parent]
     } else {
         // The root is the function itself.
-        let loc = span_start(cx, mir.span);
+        let loc = cx.lookup_debug_loc(mir.span.lo());
         debug_context.scopes[scope] = DebugScope {
             scope_metadata: Some(fn_metadata),
             file_start_pos: loc.file.start_pos,
@@ -70,16 +66,16 @@ fn make_mir_scope(
         return;
     }
 
-    let loc = span_start(cx, scope_data.span);
+    let loc = cx.lookup_debug_loc(scope_data.span.lo());
     let file_metadata = file_metadata(cx, &loc.file.name, debug_context.defining_crate);
 
     let scope_metadata = unsafe {
         Some(llvm::LLVMRustDIBuilderCreateLexicalBlock(
             DIB(cx),
             parent_scope.scope_metadata.unwrap(),
             file_metadata,
-            loc.line as c_uint,
-            loc.col.to_usize() as c_uint,
+            loc.line.unwrap_or(UNKNOWN_LINE_NUMBER),
+            loc.col.unwrap_or(UNKNOWN_COLUMN_NUMBER),
         ))
     };
     debug_context.scopes[scope] = DebugScope {

src/librustc_codegen_llvm/debuginfo/metadata.rs

@@ -5,7 +5,7 @@ use self::RecursiveTypeDescription::*;
 use super::namespace::mangled_name_of_instance;
 use super::type_names::compute_debuginfo_type_name;
 use super::utils::{
-    create_DIArray, debug_context, get_namespace_for_item, is_node_local_to_unit, span_start, DIB,
+    create_DIArray, debug_context, get_namespace_for_item, is_node_local_to_unit, DIB,
 };
 use super::CrateDebugContext;
 
@@ -2309,10 +2309,10 @@ pub fn create_global_var_metadata(cx: &CodegenCx<'ll, '_>, def_id: DefId, global
     let span = tcx.def_span(def_id);
 
     let (file_metadata, line_number) = if !span.is_dummy() {
-        let loc = span_start(cx, span);
-        (file_metadata(cx, &loc.file.name, LOCAL_CRATE), loc.line as c_uint)
+        let loc = cx.lookup_debug_loc(span.lo());
+        (file_metadata(cx, &loc.file.name, LOCAL_CRATE), loc.line)
     } else {
-        (unknown_file_metadata(cx), UNKNOWN_LINE_NUMBER)
+        (unknown_file_metadata(cx), None)
     };
 
     let is_local_to_unit = is_node_local_to_unit(cx, def_id);
@@ -2339,7 +2339,7 @@ pub fn create_global_var_metadata(cx: &CodegenCx<'ll, '_>, def_id: DefId, global
             linkage_name.as_ptr().cast(),
             linkage_name.len(),
             file_metadata,
-            line_number,
+            line_number.unwrap_or(UNKNOWN_LINE_NUMBER),
             type_metadata,
             is_local_to_unit,
             global,

src/librustc_codegen_llvm/debuginfo/mod.rs

@@ -3,10 +3,10 @@ mod doc;
 
 use rustc_codegen_ssa::mir::debuginfo::VariableKind::*;
 
-use self::metadata::{file_metadata, type_metadata, TypeMap};
+use self::metadata::{file_metadata, type_metadata, TypeMap, UNKNOWN_LINE_NUMBER};
 use self::namespace::mangled_name_of_instance;
 use self::type_names::compute_debuginfo_type_name;
-use self::utils::{create_DIArray, is_node_local_to_unit, span_start, DIB};
+use self::utils::{create_DIArray, is_node_local_to_unit, DIB};
 
 use crate::llvm;
 use crate::llvm::debuginfo::{
@@ -248,7 +248,7 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
 
         let def_id = instance.def_id();
         let containing_scope = get_containing_scope(self, instance);
-        let loc = span_start(self, span);
+        let loc = self.lookup_debug_loc(span.lo());
         let file_metadata = file_metadata(self, &loc.file.name, def_id.krate);
 
         let function_type_metadata = unsafe {
@@ -304,9 +304,9 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                 linkage_name.as_ptr().cast(),
                 linkage_name.len(),
                 file_metadata,
-                loc.line as c_uint,
+                loc.line.unwrap_or(UNKNOWN_LINE_NUMBER),
                 function_type_metadata,
-                scope_line as c_uint,
+                scope_line.unwrap_or(UNKNOWN_LINE_NUMBER),
                 flags,
                 spflags,
                 llfn,
@@ -530,7 +530,7 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
         variable_kind: VariableKind,
         span: Span,
     ) -> &'ll DIVariable {
-        let loc = span_start(self, span);
+        let loc = self.lookup_debug_loc(span.lo());
         let file_metadata = file_metadata(self, &loc.file.name, dbg_context.defining_crate);
 
         let type_metadata = type_metadata(self, variable_type, span);
@@ -550,7 +550,7 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
                 name.as_ptr().cast(),
                 name.len(),
                 file_metadata,
-                loc.line as c_uint,
+                loc.line.unwrap_or(UNKNOWN_LINE_NUMBER),
                 type_metadata,
                 true,
                 DIFlags::FlagZero,

src/librustc_codegen_llvm/debuginfo/source_loc.rs

@@ -1,32 +1,58 @@
-use super::metadata::UNKNOWN_COLUMN_NUMBER;
-use super::utils::{debug_context, span_start};
+use super::metadata::{UNKNOWN_COLUMN_NUMBER, UNKNOWN_LINE_NUMBER};
+use super::utils::debug_context;
 
 use crate::common::CodegenCx;
 use crate::llvm::debuginfo::DIScope;
 use crate::llvm::{self, Value};
 use rustc_codegen_ssa::traits::*;
 
-use libc::c_uint;
-use rustc_span::{Pos, Span};
+use rustc_data_structures::sync::Lrc;
+use rustc_span::{BytePos, Pos, SourceFile, SourceFileAndLine, Span};
+
+/// A source code location used to generate debug information.
+pub struct DebugLoc {
+    /// Information about the original source file.
+    pub file: Lrc<SourceFile>,
+    /// The (1-based) line number.
+    pub line: Option<u32>,
+    /// The (1-based) column number.
+    pub col: Option<u32>,
+}
 
 impl CodegenCx<'ll, '_> {
-    pub fn create_debug_loc(&self, scope: &'ll DIScope, span: Span) -> &'ll Value {
-        let loc = span_start(self, span);
+    /// Looks up debug source information about a `BytePos`.
+    pub fn lookup_debug_loc(&self, pos: BytePos) -> DebugLoc {
+        let (file, line, col) = match self.sess().source_map().lookup_line(pos) {
+            Ok(SourceFileAndLine { sf: file, line }) => {
+                let line_pos = file.line_begin_pos(pos);
+
+                // Use 1-based indexing.
+                let line = (line + 1) as u32;
+                let col = (pos - line_pos).to_u32() + 1;
+
+                (file, Some(line), Some(col))
+            }
+            Err(file) => (file, None, None),
+        };
 
-        // For MSVC, set the column number to zero.
+        // For MSVC, omit the column number.
         // Otherwise, emit it. This mimics clang behaviour.
         // See discussion in https://github.com/rust-lang/rust/issues/42921
-        let col_used = if self.sess().target.target.options.is_like_msvc {
-            UNKNOWN_COLUMN_NUMBER
+        if self.sess().target.target.options.is_like_msvc {
+            DebugLoc { file, line, col: None }
         } else {
-            loc.col.to_usize() as c_uint
-        };
+            DebugLoc { file, line, col }
+        }
+    }
+
+    pub fn create_debug_loc(&self, scope: &'ll DIScope, span: Span) -> &'ll Value {
+        let DebugLoc { line, col, .. } = self.lookup_debug_loc(span.lo());
 
         unsafe {
             llvm::LLVMRustDIBuilderCreateDebugLocation(
                 debug_context(self).llcontext,
-                loc.line as c_uint,
-                col_used,
+                line.unwrap_or(UNKNOWN_LINE_NUMBER),
+                col.unwrap_or(UNKNOWN_COLUMN_NUMBER),
                 scope,
                 None,
             )

src/librustc_codegen_llvm/debuginfo/utils.rs

@@ -9,9 +9,6 @@ use rustc_hir::def_id::DefId;
 use crate::common::CodegenCx;
 use crate::llvm;
 use crate::llvm::debuginfo::{DIArray, DIBuilder, DIDescriptor, DIScope};
-use rustc_codegen_ssa::traits::*;
-
-use rustc_span::Span;
 
 pub fn is_node_local_to_unit(cx: &CodegenCx<'_, '_>, def_id: DefId) -> bool {
     // The is_local_to_unit flag indicates whether a function is local to the
@@ -32,11 +29,6 @@ pub fn create_DIArray(builder: &DIBuilder<'ll>, arr: &[Option<&'ll DIDescriptor>
     };
 }
 
-/// Returns rustc_span::Loc corresponding to the beginning of the span
-pub fn span_start(cx: &CodegenCx<'_, '_>, span: Span) -> rustc_span::Loc {
-    cx.sess().source_map().lookup_char_pos(span.lo())
-}
-
 #[inline]
 pub fn debug_context(cx: &'a CodegenCx<'ll, 'tcx>) -> &'a CrateDebugContext<'ll, 'tcx> {
     cx.dbg_cx.as_ref().unwrap()

src/librustc_data_structures/frozen.rs

@@ -0,0 +1,63 @@
+//! An immutable, owned value (except for interior mutability).
+//!
+//! The purpose of `Frozen` is to make a value immutable for the sake of defensive programming. For example,
+//! suppose we have the following:
+//!
+//! ```rust
+//! struct Bar { /* some data */ }
+//!
+//! struct Foo {
+//!     /// Some computed data that should never change after construction.
+//!     pub computed: Bar,
+//!
+//!     /* some other fields */
+//! }
+//!
+//! impl Bar {
+//!     /// Mutate the `Bar`.
+//!     pub fn mutate(&mut self) { }
+//! }
+//! ```
+//!
+//! Now suppose we want to pass around a mutable `Foo` instance but, we want to make sure that
+//! `computed` does not change accidentally (e.g. somebody might accidentally call
+//! `foo.computed.mutate()`). This is what `Frozen` is for. We can do the following:
+//!
+//! ```rust
+//! use rustc_data_structures::frozen::Frozen;
+//!
+//! struct Foo {
+//!     /// Some computed data that should never change after construction.
+//!     pub computed: Frozen<Bar>,
+//!
+//!     /* some other fields */
+//! }
+//! ```
+//!
+//! `Frozen` impls `Deref`, so we can ergonomically call methods on `Bar`, but it doesn't `impl
+//! DerefMut`.  Now calling `foo.compute.mutate()` will result in a compile-time error stating that
+//! `mutate` requires a mutable reference but we don't have one.
+//!
+//! # Caveats
+//!
+//! - `Frozen` doesn't try to defend against interior mutability (e.g. `Frozen<RefCell<Bar>>`).
+//! - `Frozen` doesn't pin it's contents (e.g. one could still do `foo.computed =
+//!    Frozen::freeze(new_bar)`).
+
+/// An owned immutable value.
+#[derive(Debug)]
+pub struct Frozen<T>(T);
+
+impl<T> Frozen<T> {
+    pub fn freeze(val: T) -> Self {
+        Frozen(val)
+    }
+}
+
+impl<T> std::ops::Deref for Frozen<T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        &self.0
+    }
+}

src/librustc_data_structures/lib.rs

@@ -94,6 +94,7 @@ pub mod profiling;
 pub mod vec_linked_list;
 pub mod work_queue;
 pub use atomic_ref::AtomicRef;
+pub mod frozen;
 
 pub struct OnDrop<F: Fn()>(pub F);
 

src/librustc_error_codes/error_codes.rs

@@ -380,6 +380,7 @@ E0689: include_str!("./error_codes/E0689.md"),
 E0690: include_str!("./error_codes/E0690.md"),
 E0691: include_str!("./error_codes/E0691.md"),
 E0692: include_str!("./error_codes/E0692.md"),
+E0693: include_str!("./error_codes/E0693.md"),
 E0695: include_str!("./error_codes/E0695.md"),
 E0697: include_str!("./error_codes/E0697.md"),
 E0698: include_str!("./error_codes/E0698.md"),
@@ -595,7 +596,6 @@ E0748: include_str!("./error_codes/E0748.md"),
     E0667, // `impl Trait` in projections
     E0687, // in-band lifetimes cannot be used in `fn`/`Fn` syntax
     E0688, // in-band lifetimes cannot be mixed with explicit lifetime binders
-    E0693, // incorrect `repr(align)` attribute format
 //  E0694, // an unknown tool name found in scoped attributes
     E0696, // `continue` pointing to a labeled block
 //  E0702, // replaced with a generic attribute input check

src/librustc_error_codes/error_codes/E0117.md

@@ -1,4 +1,4 @@
-The `Drop` trait was implemented on a non-struct type.
+Only traits defined in the current crate can be implemented for arbitrary types.
 
 Erroneous code example: