Rollup of 12 pull requests

compiler/rustc_ast/src/util/literal.rs

@@ -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)
 }
 

compiler/rustc_codegen_gcc/.github/workflows/ci.yml

@@ -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

compiler/rustc_codegen_gcc/.github/workflows/rustup.yml

@@ -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 }}

compiler/rustc_codegen_gcc/Cargo.lock

@@ -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",
 ]

compiler/rustc_codegen_gcc/Cargo.toml

@@ -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.

compiler/rustc_codegen_gcc/build_system/src/build.rs

@@ -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:?}"

compiler/rustc_codegen_gcc/doc/subtree.md

@@ -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.

compiler/rustc_codegen_gcc/libgccjit.version

@@ -1 +1 @@
-37ea7cd851f04ee6a313c5067c9fde9328f876aa
+e1c6e07b095d091177376a163da44039475e05e3

compiler/rustc_codegen_gcc/rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2026-10-19"
+channel = "nightly-2026-10-24"
 components = ["rust-src", "rustc-dev", "llvm-tools-preview"]

compiler/rustc_codegen_gcc/src/attributes.rs

@@ -20,7 +20,7 @@ use crate::base;
 use crate::context::CodegenCx;
 #[cfg(feature = "master")]
 use crate::gcc_util::to_gcc_aarch64_extension;
-use crate::gcc_util::to_gcc_features;
+use crate::gcc_util::{to_gcc_features, to_gcc_target_attribute_feature};
 
 /// Checks if the function `instance` is recursively inline.
 /// Returns `false` if a functions is guaranteed to be non-recursive, and `true` if it *might* be recursive.
@@ -192,20 +192,7 @@ pub fn from_fn_attrs<'gcc, 'tcx>(
     }
     let target_features = function_features
         .iter()
-        .filter_map(|feature| {
-            // FIXME(antoyo): support soft-float.
-            if feature.contains("soft-float") {
-                return None;
-            }
-
-            if feature.starts_with('-') {
-                Some(format!("no{}", feature))
-            } else if let Some(stripped) = feature.strip_prefix('+') {
-                Some(stripped.to_string())
-            } else {
-                Some(feature.to_string())
-            }
-        })
+        .filter_map(|feature| to_gcc_target_attribute_feature(feature))
         .collect::<Vec<_>>()
         .join(",");
     if !target_features.is_empty() {

compiler/rustc_codegen_gcc/src/common.rs

@@ -28,12 +28,14 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
         self.const_uint(self.type_u16(), i as u64)
     }
 
-    fn global_string(&self, string: &str) -> LValue<'gcc> {
-        // FIXME(antoyo): handle non-null-terminated strings.
-        let string = self.context.new_string_literal(string);
+    fn global_const_string(&self, string: &str) -> LValue<'gcc> {
+        // The bytes of a Rust string are not NUL-terminated and can contain NULs.
+        let string = bytes_in_context(self, string.as_bytes());
         let sym = self.generate_local_symbol_name("str");
         let global = self.declare_private_global(&sym, self.val_ty(string));
         global.global_set_initializer_rvalue(string);
+        #[cfg(feature = "master")]
+        global.global_set_readonly();
         global
         // FIXME(antoyo): set linkage.
     }
@@ -126,18 +128,6 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
     }
 }
 
-/// The element type and element count of the array used to represent a run of `len` constant bytes.
-///
-/// Larger integers are used where possible: this reduces the number of rvalues, which is a
-/// significant memory saving on constant-heavy crates.
-fn byte_run_shape<'gcc>(cx: &CodegenCx<'gcc, '_>, len: usize) -> (Type<'gcc>, u64) {
-    match len % 8 {
-        0 => (cx.context.new_type::<u64>(), len as u64 / 8),
-        4 => (cx.context.new_type::<u32>(), len as u64 / 4),
-        _ => (cx.context.new_type::<u8>(), len as u64),
-    }
-}
-
 /// The type [`bytes_in_context`] gives a run of `len` constant bytes.
 ///
 /// Exposed separately so that the type of a constant allocation can be computed before any of its
@@ -147,65 +137,30 @@ fn byte_run_shape<'gcc>(cx: &CodegenCx<'gcc, '_>, len: usize) -> (Type<'gcc>, u6
 /// Two equal-but-distinct array types would key [`CodegenCx::type_struct`] differently and so
 /// produce two distinct anonymous structs, and libgccjit compares struct types by identity.
 pub fn bytes_type_in_context<'gcc>(cx: &CodegenCx<'gcc, '_>, len: usize) -> Type<'gcc> {
-    let (element_type, count) = byte_run_shape(cx, len);
-    if let Some(&typ) = cx.byte_array_types.borrow().get(&(element_type, count)) {
+    if let Some(&typ) = cx.byte_array_types.borrow().get(&len) {
         return typ;
     }
-    let typ = new_array_type(cx.context, None, element_type, count);
-    cx.byte_array_types.borrow_mut().insert((element_type, count), typ);
+    let typ = new_array_type(cx.context, None, cx.type_u8(), len as u64);
+    cx.byte_array_types.borrow_mut().insert(len, typ);
     typ
 }
 
-// FIXME(FractalFir): Consider using `global_set_initializer` instead. Before this is done, we need to confirm that
-// `global_set_initializer` is more memory efficient than the current solution.
-// `global_set_initializer` calls `global_set_initializer_rvalue` under the hood - does it generate an array of rvalues,
-// or is it using a more efficient representation?
 pub fn bytes_in_context<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, bytes: &[u8]) -> RValue<'gcc> {
     let typ = bytes_type_in_context(cx, bytes.len());
-    let (element_type, _) = byte_run_shape(cx, bytes.len());
-    let context = &cx.context;
-    // Since we are representing arbitrary byte runs as integers, we need to follow the target
-    // endianness.
-    let endian = cx.sess().target.options.endian;
-    let elements: Vec<_> = match bytes.len() % 8 {
-        0 => {
-            let (arrays, remainder) = bytes.as_chunks::<8>();
-            debug_assert!(remainder.is_empty());
-            arrays
-                .iter()
-                .map(|&arr| {
-                    context.new_rvalue_from_long(
-                        element_type,
-                        match endian {
-                            rustc_abi::Endian::Little => u64::from_le_bytes(arr) as i64,
-                            rustc_abi::Endian::Big => u64::from_be_bytes(arr) as i64,
-                        },
-                    )
-                })
-                .collect()
-        }
-        4 => {
-            let (arrays, remainder) = bytes.as_chunks::<4>();
-            debug_assert!(remainder.is_empty());
-            arrays
-                .iter()
-                .map(|&arr| {
-                    context.new_rvalue_from_int(
-                        element_type,
-                        match endian {
-                            rustc_abi::Endian::Little => u32::from_le_bytes(arr) as i32,
-                            rustc_abi::Endian::Big => u32::from_be_bytes(arr) as i32,
-                        },
-                    )
-                })
-                .collect()
-        }
-        _ => bytes
+    // Raw bytes take far less RAM in libgccjit than one rvalue per array element.
+    #[cfg(feature = "master")]
+    {
+        cx.context.new_array_from_bytes(None, typ, bytes)
+    }
+    #[cfg(not(feature = "master"))]
+    {
+        let byte_type = cx.type_u8();
+        let elements: Vec<_> = bytes
             .iter()
-            .map(|&byte| context.new_rvalue_from_int(element_type, byte as i32))
-            .collect(),
-    };
-    context.new_array_constructor(None, typ, &elements)
+            .map(|&byte| cx.context.new_rvalue_from_int(byte_type, byte as i32))
+            .collect();
+        cx.context.new_array_constructor(None, typ, &elements)
+    }
 }
 
 pub fn type_is_pointer(typ: Type<'_>) -> bool {
@@ -292,7 +247,7 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
     fn const_str(&self, s: &str) -> (RValue<'gcc>, RValue<'gcc>) {
         let mut const_str_cache = self.const_str_cache.borrow_mut();
         let str_global = const_str_cache.get(s).copied().unwrap_or_else(|| {
-            let g = self.global_string(s);
+            let g = self.global_const_string(s);
             const_str_cache.insert(s.to_owned(), g);
             g
         });