Merge pull request #820 from rust-lang/sync_from_rust_2025_12_20

Sync from rust 2025/12/20

Author: antoyo

build_system/src/build.rs

@@ -111,14 +111,20 @@ pub fn build_sysroot(env: &HashMap<String, String>, config: &ConfigInfo) -> Resu
 
     // Symlink libgccjit.so to sysroot.
     let lib_path = start_dir.join("sysroot").join("lib");
+    let rustlib_target_path = lib_path
+        .join("rustlib")
+        .join(&config.host_triple)
+        .join("codegen-backends")
+        .join("lib")
+        .join(&config.target_triple);
     let libgccjit_path =
         PathBuf::from(config.gcc_path.as_ref().expect("libgccjit should be set by this point"))
             .join("libgccjit.so");
-    let libgccjit_in_sysroot_path = lib_path.join("libgccjit.so");
+    let libgccjit_in_sysroot_path = rustlib_target_path.join("libgccjit.so");
     // First remove the file to be able to create the symlink even when the file already exists.
     let _ = fs::remove_file(&libgccjit_in_sysroot_path);
-    create_dir(&lib_path)?;
-    symlink(libgccjit_path, libgccjit_in_sysroot_path)
+    create_dir(&rustlib_target_path)?;
+    symlink(libgccjit_path, &libgccjit_in_sysroot_path)
         .map_err(|error| format!("Cannot create symlink for libgccjit.so: {}", error))?;
 
     let library_dir = start_dir.join("sysroot_src").join("library");

rust-toolchain

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2025-11-24"
+channel = "nightly-2025-12-20"
 components = ["rust-src", "rustc-dev", "llvm-tools-preview"]

src/allocator.rs

@@ -1,12 +1,11 @@
 #[cfg(feature = "master")]
 use gccjit::FnAttribute;
-use gccjit::{Context, FunctionType, RValue, ToRValue, Type};
+use gccjit::{Context, FunctionType, ToRValue, Type};
 use rustc_ast::expand::allocator::{
     AllocatorMethod, AllocatorTy, NO_ALLOC_SHIM_IS_UNSTABLE, default_fn_name, global_fn_name,
 };
 use rustc_middle::bug;
 use rustc_middle::ty::TyCtxt;
-use rustc_session::config::OomStrategy;
 use rustc_symbol_mangling::mangle_internal_symbol;
 
 use crate::GccContext;
@@ -59,14 +58,6 @@ pub(crate) unsafe fn codegen(
         create_wrapper_function(tcx, context, &from_name, Some(&to_name), &types, output);
     }
 
-    create_const_value_function(
-        tcx,
-        context,
-        &mangle_internal_symbol(tcx, OomStrategy::SYMBOL),
-        i8,
-        context.new_rvalue_from_int(i8, tcx.sess.opts.unstable_opts.oom.should_panic() as i32),
-    );
-
     create_wrapper_function(
         tcx,
         context,
@@ -77,34 +68,6 @@ pub(crate) unsafe fn codegen(
     );
 }
 
-fn create_const_value_function(
-    tcx: TyCtxt<'_>,
-    context: &Context<'_>,
-    name: &str,
-    output: Type<'_>,
-    value: RValue<'_>,
-) {
-    let func = context.new_function(None, FunctionType::Exported, output, &[], name, false);
-
-    #[cfg(feature = "master")]
-    {
-        func.add_attribute(FnAttribute::Visibility(symbol_visibility_to_gcc(
-            tcx.sess.default_visibility(),
-        )));
-
-        // FIXME(antoyo): cg_llvm sets AlwaysInline, but AlwaysInline is different in GCC and using
-        // it here will causes linking errors when using LTO.
-        func.add_attribute(FnAttribute::Inline);
-    }
-
-    if tcx.sess.must_emit_unwind_tables() {
-        // TODO(antoyo): emit unwind tables.
-    }
-
-    let block = func.new_block("entry");
-    block.end_with_return(None, value);
-}
-
 fn create_wrapper_function(
     tcx: TyCtxt<'_>,
     context: &Context<'_>,

src/asm.rs

@@ -209,10 +209,16 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                                 }
                                 ("r", dummy_output_type(self.cx, reg.reg_class()))
                             } else {
-                                // `clobber_abi` can add lots of clobbers that are not supported by the target,
-                                // such as AVX-512 registers, so we just ignore unsupported registers
-                                let is_target_supported =
-                                    reg.reg_class().supported_types(asm_arch, true).iter().any(
+                                let is_target_supported = match reg.reg_class() {
+                                    // `clobber_abi` clobbers spe_acc on all PowerPC targets. This
+                                    // register is unique to the powerpc*spe target, and the target
+                                    // is not supported by gcc. Ignore it.
+                                    InlineAsmRegClass::PowerPC(
+                                        PowerPCInlineAsmRegClass::spe_acc,
+                                    ) => false,
+                                    // `clobber_abi` can add lots of clobbers that are not supported by the target,
+                                    // such as AVX-512 registers, so we just ignore unsupported registers
+                                    x => x.supported_types(asm_arch, true).iter().any(
                                         |&(_, feature)| {
                                             if let Some(feature) = feature {
                                                 self.tcx
@@ -222,7 +228,8 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                                                 true // Register class is unconditionally supported
                                             }
                                         },
-                                    );
+                                    ),
+                                };
 
                                 if is_target_supported && !clobbers.contains(&reg_name) {
                                     clobbers.push(reg_name);
@@ -710,7 +717,8 @@ fn reg_class_to_gcc(reg_class: InlineAsmRegClass) -> &'static str {
             PowerPCInlineAsmRegClass::cr
             | PowerPCInlineAsmRegClass::ctr
             | PowerPCInlineAsmRegClass::lr
-            | PowerPCInlineAsmRegClass::xer,
+            | PowerPCInlineAsmRegClass::xer
+            | PowerPCInlineAsmRegClass::spe_acc,
         ) => {
             unreachable!("clobber-only")
         }
@@ -793,7 +801,8 @@ fn dummy_output_type<'gcc, 'tcx>(cx: &CodegenCx<'gcc, 'tcx>, reg: InlineAsmRegCl
             PowerPCInlineAsmRegClass::cr
             | PowerPCInlineAsmRegClass::ctr
             | PowerPCInlineAsmRegClass::lr
-            | PowerPCInlineAsmRegClass::xer,
+            | PowerPCInlineAsmRegClass::xer
+            | PowerPCInlineAsmRegClass::spe_acc,
         ) => {
             unreachable!("clobber-only")
         }

src/builder.rs

@@ -500,12 +500,12 @@ impl<'gcc, 'tcx> BackendTypes for Builder<'_, 'gcc, 'tcx> {
 }
 
 fn set_rvalue_location<'a, 'gcc, 'tcx>(
-    bx: &mut Builder<'a, 'gcc, 'tcx>,
+    _bx: &mut Builder<'a, 'gcc, 'tcx>,
     rvalue: RValue<'gcc>,
 ) -> RValue<'gcc> {
-    if bx.location.is_some() {
-        #[cfg(feature = "master")]
-        rvalue.set_location(bx.location.unwrap());
+    #[cfg(feature = "master")]
+    if let Some(location) = _bx.location {
+        rvalue.set_location(location);
     }
     rvalue
 }
@@ -943,6 +943,10 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
             .get_address(self.location)
     }
 
+    fn scalable_alloca(&mut self, _elt: u64, _align: Align, _element_ty: Ty<'_>) -> RValue<'gcc> {
+        todo!()
+    }
+
     fn load(&mut self, pointee_ty: Type<'gcc>, ptr: RValue<'gcc>, align: Align) -> RValue<'gcc> {
         let block = self.llbb();
         let function = block.get_function();

src/debuginfo.rs

@@ -297,29 +297,11 @@ impl<'gcc, 'tcx> DebugInfoCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         let pos = span.lo();
         let DebugLoc { file, line, col } = self.lookup_debug_loc(pos);
         match file.name {
-            rustc_span::FileName::Real(ref name) => match *name {
-                rustc_span::RealFileName::LocalPath(ref name) => {
-                    if let Some(name) = name.to_str() {
-                        self.context.new_location(name, line as i32, col as i32)
-                    } else {
-                        Location::null()
-                    }
-                }
-                rustc_span::RealFileName::Remapped {
-                    ref local_path,
-                    virtual_name: ref _unused,
-                } => {
-                    if let Some(name) = local_path.as_ref() {
-                        if let Some(name) = name.to_str() {
-                            self.context.new_location(name, line as i32, col as i32)
-                        } else {
-                            Location::null()
-                        }
-                    } else {
-                        Location::null()
-                    }
-                }
-            },
+            rustc_span::FileName::Real(ref name) => self.context.new_location(
+                name.path(rustc_span::RemapPathScopeComponents::DEBUGINFO).to_string_lossy(),
+                line as i32,
+                col as i32,
+            ),
             _ => Location::null(),
         }
     }

src/gcc_util.rs

@@ -33,11 +33,7 @@ pub(crate) fn global_gcc_features(sess: &Session) -> Vec<String> {
     // should be taken in cases like these.
     let mut features = vec![];
 
-    // Features implied by an implicit or explicit `--target`.
-    features.extend(sess.target.features.split(',').filter(|v| !v.is_empty()).map(String::from));
-
-    // -Ctarget-features
-    target_features::flag_to_backend_features(sess, |feature, enable| {
+    let mut extend_backend_features = |feature: &str, enable: bool| {
         // We run through `to_gcc_features` when
         // passing requests down to GCC. This means that all in-language
         // features also work on the command line instead of having two
@@ -48,7 +44,13 @@ pub(crate) fn global_gcc_features(sess: &Session) -> Vec<String> {
                 .flat_map(|feat| to_gcc_features(sess, feat).into_iter())
                 .map(|feature| if !enable { format!("-{}", feature) } else { feature.to_string() }),
         );
-    });
+    };
+
+    // Features implied by an implicit or explicit `--target`.
+    target_features::target_spec_to_backend_features(sess, &mut extend_backend_features);
+
+    // -Ctarget-features
+    target_features::flag_to_backend_features(sess, extend_backend_features);
 
     gcc_features_by_flags(sess, &mut features);
 
@@ -66,6 +68,7 @@ pub fn to_gcc_features<'a>(sess: &Session, s: &'a str) -> SmallVec<[&'a str; 2]>
         (&Arch::X86 | &Arch::X86_64, "rdrand") => smallvec!["rdrnd"],
         (&Arch::X86 | &Arch::X86_64, "bmi1") => smallvec!["bmi"],
         (&Arch::X86 | &Arch::X86_64, "cmpxchg16b") => smallvec!["cx16"],
+        (&Arch::X86 | &Arch::X86_64, "lahfsahf") => smallvec!["sahf"],
         (&Arch::X86 | &Arch::X86_64, "avx512vaes") => smallvec!["vaes"],
         (&Arch::X86 | &Arch::X86_64, "avx512gfni") => smallvec!["gfni"],
         (&Arch::X86 | &Arch::X86_64, "avx512vpclmulqdq") => smallvec!["vpclmulqdq"],

src/intrinsic/mod.rs

@@ -424,9 +424,10 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
                         }
                         sym::bitreverse => self.bit_reverse(width, args[0].immediate()),
                         sym::rotate_left | sym::rotate_right => {
-                            // TODO(antoyo): implement using algorithm from:
+                            // Using optimized branchless algorithm from:
                             // https://blog.regehr.org/archives/1063
-                            // for other platforms.
+                            // This implementation uses the pattern (x<<n) | (x>>(-n&(width-1)))
+                            // which generates efficient code for other platforms.
                             let is_left = name == sym::rotate_left;
                             let val = args[0].immediate();
                             let raw_shift = args[1].immediate();
@@ -467,7 +468,7 @@ impl<'a, 'gcc, 'tcx> IntrinsicCallBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tc
                 let layout = self.layout_of(tp_ty).layout;
                 let _use_integer_compare = match layout.backend_repr() {
                     Scalar(_) | ScalarPair(_, _) => true,
-                    SimdVector { .. } => false,
+                    SimdVector { .. } | ScalableVector { .. } => false,
                     Memory { .. } => {
                         // For rusty ABIs, small aggregates are actually passed
                         // as `RegKind::Integer` (see `FnAbi::adjust_for_abi`),

src/intrinsic/simd.rs

@@ -774,24 +774,23 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
                 return Err(());
             }};
         }
-        let (elem_ty_str, elem_ty, cast_type) = if let ty::Float(ref f) = *in_elem.kind() {
-            let elem_ty = bx.cx.type_float_from_ty(*f);
-            match f.bit_width() {
-                16 => ("", elem_ty, Some(bx.cx.double_type)),
-                32 => ("f", elem_ty, None),
-                64 => ("", elem_ty, None),
-                _ => {
-                    return_error!(InvalidMonomorphization::FloatingPointVector {
-                        span,
-                        name,
-                        f_ty: *f,
-                        in_ty
-                    });
-                }
-            }
-        } else {
+        let ty::Float(ref f) = *in_elem.kind() else {
             return_error!(InvalidMonomorphization::FloatingPointType { span, name, in_ty });
         };
+        let elem_ty = bx.cx.type_float_from_ty(*f);
+        let (elem_ty_str, elem_ty, cast_type) = match f.bit_width() {
+            16 => ("", elem_ty, Some(bx.cx.double_type)),
+            32 => ("f", elem_ty, None),
+            64 => ("", elem_ty, None),
+            _ => {
+                return_error!(InvalidMonomorphization::FloatingPointVector {
+                    span,
+                    name,
+                    f_ty: *f,
+                    in_ty
+                });
+            }
+        };
 
         let vec_ty = bx.cx.type_vector(elem_ty, in_len);
 

src/lib.rs

@@ -181,18 +181,12 @@ pub struct GccCodegenBackend {
 
 static LTO_SUPPORTED: AtomicBool = AtomicBool::new(false);
 
-fn libgccjit_path(sysroot_path: &Path) -> PathBuf {
-    let sysroot_lib_dir = sysroot_path.join("lib");
-    sysroot_lib_dir.join("libgccjit.so")
-}
-
-fn load_libgccjit_if_needed(sysroot_path: &Path) {
+fn load_libgccjit_if_needed(libgccjit_target_lib_file: &Path) {
     if gccjit::is_loaded() {
         // Do not load a libgccjit second time.
         return;
     }
 
-    let libgccjit_target_lib_file = libgccjit_path(sysroot_path);
     let path = libgccjit_target_lib_file.to_str().expect("libgccjit path");
 
     let string = CString::new(path).expect("string to libgccjit path");
@@ -212,17 +206,38 @@ impl CodegenBackend for GccCodegenBackend {
     }
 
     fn init(&self, sess: &Session) {
+        fn file_path(sysroot_path: &Path, sess: &Session) -> PathBuf {
+            let rustlib_path =
+                rustc_target::relative_target_rustlib_path(sysroot_path, &sess.host.llvm_target);
+            sysroot_path
+                .join(rustlib_path)
+                .join("codegen-backends")
+                .join("lib")
+                .join(sess.target.llvm_target.as_ref())
+                .join("libgccjit.so")
+        }
+
         // We use all_paths() instead of only path() in case the path specified by --sysroot is
         // invalid.
         // This is the case for instance in Rust for Linux where they specify --sysroot=/dev/null.
         for path in sess.opts.sysroot.all_paths() {
-            let libgccjit_target_lib_file = libgccjit_path(path);
-            if let Ok(true) = fs::exists(libgccjit_target_lib_file) {
-                load_libgccjit_if_needed(path);
+            let libgccjit_target_lib_file = file_path(path, sess);
+            if let Ok(true) = fs::exists(&libgccjit_target_lib_file) {
+                load_libgccjit_if_needed(&libgccjit_target_lib_file);
                 break;
             }
         }
 
+        if !gccjit::is_loaded() {
+            let mut paths = vec![];
+            for path in sess.opts.sysroot.all_paths() {
+                let libgccjit_target_lib_file = file_path(path, sess);
+                paths.push(libgccjit_target_lib_file);
+            }
+
+            panic!("Could not load libgccjit.so. Attempted paths: {:#?}", paths);
+        }
+
         #[cfg(feature = "master")]
         {
             let target_cpu = target_cpu(sess);