Auto merge of rust-lang#140012 - matthiaskrgr:rollup-6fceiyg, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - rust-lang#137454 (not lint break with label and unsafe block)
 - rust-lang#138934 (support config extensions)
 - rust-lang#139297 (Deduplicate & clean up Nix shell)
 - rust-lang#139834 (Don't canonicalize crate paths)
 - rust-lang#139868 (Move `pal::env` into `std::sys::env_consts`)
 - rust-lang#139978 (Add citool command for generating a test dashboard)
 - rust-lang#140000 (skip llvm-config in autodiff check builds, when its unavailable)
 - rust-lang#140007 (Disable has_thread_local on i686-win7-windows-msvc)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

Diff for: bootstrap.example.toml

@@ -19,6 +19,14 @@
 # Note that this has no default value (x.py uses the defaults in `bootstrap.example.toml`).
 #profile = <none>
 
+# Inherits configuration values from different configuration files (a.k.a. config extensions).
+# Supports absolute paths, and uses the current directory (where the bootstrap was invoked)
+# as the base if the given path is not absolute.
+#
+# The overriding logic follows a right-to-left order. For example, in `include = ["a.toml", "b.toml"]`,
+# extension `b.toml` overrides `a.toml`. Also, parent extensions always overrides the inner ones.
+#include = []
+
 # Keeps track of major changes made to this configuration.
 #
 # This value also represents ID of the PR that caused major changes. Meaning,

Diff for: compiler/rustc_metadata/src/locator.rs

@@ -427,12 +427,21 @@ impl<'a> CrateLocator<'a> {
 
                         let (rlibs, rmetas, dylibs) =
                             candidates.entry(hash.to_string()).or_default();
-                        let path =
-                            try_canonicalize(&spf.path).unwrap_or_else(|_| spf.path.to_path_buf());
-                        if seen_paths.contains(&path) {
-                            continue;
-                        };
-                        seen_paths.insert(path.clone());
+                        {
+                            // As a perforamnce optimisation we canonicalize the path and skip
+                            // ones we've already seeen. This allows us to ignore crates
+                            // we know are exactual equal to ones we've already found.
+                            // Going to the same crate through different symlinks does not change the result.
+                            let path = try_canonicalize(&spf.path)
+                                .unwrap_or_else(|_| spf.path.to_path_buf());
+                            if seen_paths.contains(&path) {
+                                continue;
+                            };
+                            seen_paths.insert(path);
+                        }
+                        // Use the original path (potentially with unresolved symlinks),
+                        // filesystem code should not care, but this is nicer for diagnostics.
+                        let path = spf.path.to_path_buf();
                         match kind {
                             CrateFlavor::Rlib => rlibs.insert(path, search_path.kind),
                             CrateFlavor::Rmeta => rmetas.insert(path, search_path.kind),

Diff for: compiler/rustc_parse/src/parser/expr.rs

@@ -1884,13 +1884,15 @@ impl<'a> Parser<'a> {
             let mut expr = self.parse_expr_opt()?;
             if let Some(expr) = &mut expr {
                 if label.is_some()
-                    && matches!(
-                        expr.kind,
+                    && match &expr.kind {
                         ExprKind::While(_, _, None)
-                            | ExprKind::ForLoop { label: None, .. }
-                            | ExprKind::Loop(_, None, _)
-                            | ExprKind::Block(_, None)
-                    )
+                        | ExprKind::ForLoop { label: None, .. }
+                        | ExprKind::Loop(_, None, _) => true,
+                        ExprKind::Block(block, None) => {
+                            matches!(block.rules, BlockCheckMode::Default)
+                        }
+                        _ => false,
+                    }
                 {
                     self.psess.buffer_lint(
                         BREAK_WITH_LABEL_AND_LOOP,

Diff for: compiler/rustc_target/src/spec/targets/i686_win7_windows_msvc.rs

@@ -7,6 +7,12 @@ pub(crate) fn target() -> Target {
     base.cpu = "pentium4".into();
     base.max_atomic_width = Some(64);
     base.supported_sanitizers = SanitizerSet::ADDRESS;
+    // On Windows 7 32-bit, the alignment characteristic of the TLS Directory
+    // don't appear to be respected by the PE Loader, leading to crashes. As
+    // a result, let's disable has_thread_local to make sure TLS goes through
+    // the emulation layer.
+    // See https://github.com/rust-lang/rust/issues/138903
+    base.has_thread_local = false;
 
     base.add_pre_link_args(
         LinkerFlavor::Msvc(Lld::No),

Diff for: library/std/src/env.rs

@@ -950,7 +950,7 @@ impl fmt::Debug for ArgsOs {
 /// Constants associated with the current target
 #[stable(feature = "env", since = "1.0.0")]
 pub mod consts {
-    use crate::sys::env::os;
+    use crate::sys::env_consts::os;
 
     /// A string describing the architecture of the CPU that is currently in use.
     /// An example value may be: `"x86"`, `"arm"` or `"riscv64"`.