@@ -1,6 +1,5 @@
 //! Code related to parsing literals.
 
-use std::fmt::Write as _;
 use std::{ascii, fmt, str};
 
 use rustc_literal_escaper::{
@@ -38,19 +37,8 @@ pub fn escape_string_symbol(symbol: Symbol) -> Symbol {
     let mut escaped = String::with_capacity(s.len() + 1);
     escaped.push_str(prefix);
 
-    // Don't use escape_default() here, because using it is slower than escaping manually.
-    for c in suffix.chars() {
-        match c {
-            '\t' => escaped.push_str("\\t"),
-            '\r' => escaped.push_str("\\r"),
-            '\n' => escaped.push_str("\\n"),
-            '\\' => escaped.push_str("\\\\"),
-            '\'' => escaped.push_str("\\'"),
-            '\"' => escaped.push_str("\\\""),
-            '\x20'..='\x7e' => escaped.push(c),
-            c => write!(escaped, "\\u{{{:x}}}", c as u32).unwrap(),
-        }
-    }
+    escaped.extend(suffix.escape_default());
+
     Symbol::intern(&escaped)
 }
 
 
@@ -1389,6 +1389,8 @@ pub(crate) struct InvalidTarget {
     pub attr_span: Span,
     pub name: AttrPath,
     pub target: &'static str,
+    #[context]
+    pub target_span: Span,
     pub applied: DiagArgValue,
     pub only: &'static str,
     pub attribute_args: String,
 
@@ -131,23 +131,31 @@ impl<'sess> AttributeParser<'sess> {
         let (applied, only) = allowed_targets_applied(allowed_targets, cx.target, cx.features);
         let is_diagnostic_attr = cx.attr_path.segments[0] == sym::diagnostic;
 
+        let span = if attribute_args.is_empty() {
+            // Example: for the attribute `#[inline]`, name+attribute_args gives "inline",
+            // and the path span covers `inline` which is just what we want.
+            cx.attr_path.span
+        } else {
+            // Example 1: for the attribute `#[repr(C)]`, name+attribute_args gives
+            // "repr(C)", and the inner span covers `repr(C)` which is just what we want.
+            //
+            // Example 2: for the attribute `#[repr(C, packed)]`, name+attribute_args gives
+            // "repr(C)", and the inner span covers `repr(C, packed)` which doesn't match
+            // exactly but is as close as we can get.
+            cx.inner_span
+        };
+        let target_span = if span.eq_ctxt(cx.target_span) && cx.target != Target::Crate {
+            cx.target_span.shrink_to_lo()
+        } else {
+            span
+        };
+
         let diag = InvalidTarget {
-            span: if attribute_args.is_empty() {
-                // Example: for the attribute `#[inline]`, name+attribute_args gives "inline",
-                // and the path span covers `inline` which is just what we want.
-                cx.attr_path.span
-            } else {
-                // Example 1: for the attribute `#[repr(C)]`, name+attribute_args gives
-                // "repr(C)", and the inner span covers `repr(C)` which is just what we want.
-                //
-                // Example 2: for the attribute `#[repr(C, packed)]`, name+attribute_args gives
-                // "repr(C)", and the inner span covers `repr(C, packed)` which doesn't match
-                // exactly but is as close as we can get.
-                cx.inner_span
-            },
+            span,
             attr_span: cx.attr_span,
             name: cx.attr_path.clone(),
             target: cx.target.plural_name(),
+            target_span,
             only: if only { "only " } else { "" },
             applied: DiagArgValue::StrListSepByAnd(applied.into_iter().map(Cow::Owned).collect()),
             attribute_args: attribute_args.to_string(),
 
@@ -116,8 +116,6 @@ jobs:
     - name: Set env
       run: |
         echo "workspace="$GITHUB_WORKSPACE >> $GITHUB_ENV
-        # /tmp is a small tmpfs, and rustdoc keeps every compiled doctest there until the run ends.
-        echo "TMPDIR=$RUNNER_TEMP" >> $GITHUB_ENV
 
     #- name: Cache rust repository
       ## We only clone the rust repository for rustc tests
 
@@ -77,8 +77,6 @@ jobs:
     - name: Set env
       run: |
         echo "workspace="$GITHUB_WORKSPACE >> $GITHUB_ENV
-        # /tmp is a small tmpfs, and rustdoc keeps every compiled doctest there until the run ends.
-        echo "TMPDIR=$RUNNER_TEMP" >> $GITHUB_ENV
 
     - name: Prepare
       if: ${{ matrix.run_cargo_tests }}
 
@@ -56,18 +56,18 @@ dependencies = [
 
 [[package]]
 name = "gccjit"
-version = "7.2.0"
+version = "7.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "27cd340f3c265988de3379689cbbd103c25b1f8a3d0cc73f91a49083e899d3e1"
+checksum = "ea1820165dfb376a3bbfe8b69628d9e5a851c423e0480a666f71f560e2d0a924"
 dependencies = [
  "gccjit_sys",
 ]
 
 [[package]]
 name = "gccjit_sys"
-version = "4.2.0"
+version = "4.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da2d9d74572f004908f17ec1bd0af071e5db63a12c3335c9651a6125593951c6"
+checksum = "a6091291fc118448b91df5b662d20564020198fee46d8445a6aa0c25b6b435be"
 dependencies = [
  "libc",
 ]
 
@@ -20,7 +20,7 @@ default = ["master"]
 [dependencies]
 object = { version = "0.39.0", default-features = false, features = ["std", "read"] }
 tempfile = "3.20"
-gccjit = { version = "7.2.0", features = ["dlopen"] }
+gccjit = { version = "7.3.0", features = ["dlopen"] }
 #gccjit = { git = "https://github.com/rust-lang/gccjit.rs", branch = "error-dlopen", features = ["dlopen"] }
 
 # Local copy.
 
@@ -6,7 +6,8 @@ use std::path::{Path, PathBuf};
 
 use crate::config::{Channel, ConfigInfo};
 use crate::utils::{
-    create_dir, get_sysroot_dir, run_command, run_command_with_output_and_env, walk_dir,
+    create_dir, get_sysroot_dir, run_command, run_command_with_output_and_env, rustc_version_info,
+    walk_dir,
 };
 
 #[derive(Default)]
@@ -137,17 +138,16 @@ pub fn build_sysroot(env: &HashMap<String, String>, config: &ConfigInfo) -> Resu
     // Builds libs
     let mut rustflags = env.get("RUSTFLAGS").cloned().unwrap_or_default();
 
-    // Record the sysroot sources under the path the `rust-src` component uses, which is where
-    // rustc looks for them to turn a sysroot span into `/rustc/$hash`. Without this, ui tests
-    // print the build path where they expect `$SRC_DIR`.
-    let sysroot_source_dir = lib_path.join("rustlib/src/rust/library");
+    // Remap both source spans and embedded panic locations to the standard virtual path.
+    let sysroot_source_dir = start_dir.join("sysroot_src");
+    let rustc_commit = rustc_version_info(env.get("RUSTC").map(String::as_str))?
+        .commit_hash
+        .ok_or_else(|| "Couldn't retrieve rustc commit hash".to_string())?;
+    // Cargo passes workspace-relative filenames, including those used by panic locations.
+    // Also: the `==` is intentional! The first `=` is "FROM" and the second `=` is for "TO".
+    rustflags.push_str(&format!(" --remap-path-prefix==/rustc/{rustc_commit}/library"));
     rustflags.push_str(&format!(
-        " --remap-path-prefix={library_dir}={sysroot_source_dir}",
-        library_dir = std::path::absolute(&library_dir)
-            .map_err(|error| format!(
-                "Failed to get the absolute path of the sysroot sources: {error:?}"
-            ))?
-            .display(),
+        " --remap-path-prefix={sysroot_source_dir}=/rustc/{rustc_commit}",
         sysroot_source_dir = std::path::absolute(&sysroot_source_dir)
             .map_err(|error| format!(
                 "Failed to get the absolute path of the sysroot sources: {error:?}"
 
@@ -1,54 +1,13 @@
-# git subtree sync
+# Subtree sync procedure
 
-`rustc_codegen_gcc` is a subtree of the rust compiler. As such, it needs to be
-synced from time to time to ensure changes that happened on their side are also
-included on our side.
+`rustc_codegen_gcc` is using [Josh] to perform subtree synces with the `rust-lang/rust` repository.
 
-### How to install a forked git-subtree
+[Josh]: https://josh-project.dev/docs/intro.html
 
-Using git-subtree with `rustc` requires a patched git to make it work.
-The PR that is needed is [here](https://github.com/gitgitgadget/git/pull/493).
-Use the following instructions to install it:
+The procedure for performing subtree synchronizations is documented [here][rdg-josh].
 
-```bash
-git clone git@github.com:tqc/git.git
-cd git
-git checkout tqc/subtree
-make
-make install
-cd contrib/subtree
-make
-cp git-subtree ~/bin
-```
+[rdg-josh]: https://rustc-dev-guide.rust-lang.org/external-repos.html#synchronizing-a-josh-subtree
 
-### Syncing with rust compiler
+## Pushing changes to `rust-lang/rust`
 
-Do a sync with this command:
-
-```bash
-PATH="$HOME/bin:$PATH" ~/bin/git-subtree push -P compiler/rustc_codegen_gcc/ ../rustc_codegen_gcc/ sync_branch_name
-cd ../rustc_codegen_gcc
-git checkout master
-git pull
-git checkout sync_branch_name
-git merge master
-```
-
-To send the changes to the rust repo:
-
-```bash
-cd ../rust
-git pull origin master
-git checkout -b subtree-update_cg_gcc_YYYY-MM-DD
-PATH="$HOME/bin:$PATH" ~/bin/git-subtree pull --prefix=compiler/rustc_codegen_gcc/ https://github.com/rust-lang/rustc_codegen_gcc.git master
-# Don't forget to update the `gcc` submodule to the same version as the
-# one in `rustc_codegen_gcc/libgccjit.version`.
-git push
-
-# Immediately merge the merge commit into cg_gcc to prevent merge conflicts when syncing from rust-lang/rust later.
-PATH="$HOME/bin:$PATH" ~/bin/git-subtree push -P compiler/rustc_codegen_gcc/ ../rustc_codegen_gcc/ sync_branch_name
-```
-
-FIXME: write a script that does the above.
-
-https://rust-lang.zulipchat.com/#narrow/stream/301329-t-devtools/topic/subtree.20madness/near/258877725
+If the used GCC commit (recorded in `libgccjit.version`) changed in `rustc_codegen_gcc`, then you will have to update the `gcc` submodule in the `rust-lang/rust` repository in the push sync PR. The CI in `rust-lang/rust` should ensure that these two commit references match. You can simply update the `gcc` submodule commit and push it to your push sync PR once it has been created.
@@ -1 +1 @@
-37ea7cd851f04ee6a313c5067c9fde9328f876aa
+e1c6e07b095d091177376a163da44039475e05e3
Original file line number	Diff line number	Diff line change
`@@ -1 +1 @@`
`1`		`-37ea7cd851f04ee6a313c5067c9fde9328f876aa`
	`1`	`+e1c6e07b095d091177376a163da44039475e05e3`