Rollup of 10 pull requests

compiler/rustc_codegen_gcc/example/alloc_system.rs

@@ -15,6 +15,7 @@
 const MIN_ALIGN: usize = 8;
 #[cfg(any(target_arch = "x86_64",
               target_arch = "aarch64",
+              target_arch = "loongarch64",
               target_arch = "mips64",
               target_arch = "s390x",
               target_arch = "sparc64"))]

compiler/rustc_codegen_ssa/src/back/metadata.rs

@@ -127,6 +127,7 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
         "msp430" => Architecture::Msp430,
         "hexagon" => Architecture::Hexagon,
         "bpf" => Architecture::Bpf,
+        "loongarch64" => Architecture::LoongArch64,
         // Unsupported architecture.
         _ => return None,
     };
@@ -190,6 +191,10 @@ pub(crate) fn create_object_file(sess: &Session) -> Option<write::Object<'static
             }
             e_flags
         }
+        Architecture::LoongArch64 => {
+            // Source: https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_e_flags_identifies_abi_type_and_version
+            elf::EF_LARCH_OBJABI_V1 | elf::EF_LARCH_ABI_DOUBLE_FLOAT
+        }
         _ => 0,
     };
     // adapted from LLVM's `MCELFObjectTargetWriter::getOSABI`

compiler/rustc_llvm/build.rs

@@ -10,6 +10,7 @@ const OPTIONAL_COMPONENTS: &[&str] = &[
     "aarch64",
     "amdgpu",
     "avr",
+    "loongarch",
     "m68k",
     "mips",
     "powerpc",

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -146,6 +146,12 @@ extern "C" void LLVMTimeTraceProfilerFinish(const char* FileName) {
 #define SUBTARGET_HEXAGON
 #endif
 
+#ifdef LLVM_COMPONENT_LOONGARCH
+#define SUBTARGET_LOONGARCH SUBTARGET(LoongArch)
+#else
+#define SUBTARGET_LOONGARCH
+#endif
+
 #define GEN_SUBTARGETS                                                         \
   SUBTARGET_X86                                                                \
   SUBTARGET_ARM                                                                \
@@ -159,6 +165,7 @@ extern "C" void LLVMTimeTraceProfilerFinish(const char* FileName) {
   SUBTARGET_SPARC                                                              \
   SUBTARGET_HEXAGON                                                            \
   SUBTARGET_RISCV                                                              \
+  SUBTARGET_LOONGARCH                                                          \
 
 #define SUBTARGET(x)                                                           \
   namespace llvm {                                                             \

compiler/rustc_llvm/src/lib.rs

@@ -102,6 +102,14 @@ pub fn initialize_available_targets() {
         LLVMInitializeM68kAsmPrinter,
         LLVMInitializeM68kAsmParser
     );
+    init_target!(
+        llvm_component = "loongarch",
+        LLVMInitializeLoongArchTargetInfo,
+        LLVMInitializeLoongArchTarget,
+        LLVMInitializeLoongArchTargetMC,
+        LLVMInitializeLoongArchAsmPrinter,
+        LLVMInitializeLoongArchAsmParser
+    );
     init_target!(
         llvm_component = "mips",
         LLVMInitializeMipsTargetInfo,

compiler/rustc_middle/src/ty/visit.rs

@@ -83,6 +83,9 @@ pub trait TypeVisitableExt<'tcx>: TypeVisitable<TyCtxt<'tcx>> {
                 | TypeFlags::HAS_CT_PLACEHOLDER,
         )
     }
+    fn has_non_region_placeholders(&self) -> bool {
+        self.has_type_flags(TypeFlags::HAS_TY_PLACEHOLDER | TypeFlags::HAS_CT_PLACEHOLDER)
+    }
     fn needs_subst(&self) -> bool {
         self.has_type_flags(TypeFlags::NEEDS_SUBST)
     }

compiler/rustc_target/src/spec/loongarch64_unknown_linux_gnu.rs

@@ -0,0 +1,17 @@
+use crate::spec::{Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        llvm_target: "loongarch64-unknown-linux-gnu".into(),
+        pointer_width: 64,
+        data_layout: "e-m:e-p:64:64-i64:64-i128:128-n64-S128".into(),
+        arch: "loongarch64".into(),
+        options: TargetOptions {
+            cpu: "generic".into(),
+            features: "+f,+d".into(),
+            llvm_abiname: "lp64d".into(),
+            max_atomic_width: Some(64),
+            ..super::linux_gnu_base::opts()
+        },
+    }
+}

compiler/rustc_target/src/spec/mod.rs

@@ -1021,6 +1021,7 @@ supported_targets! {
     ("x86_64-unknown-linux-gnux32", x86_64_unknown_linux_gnux32),
     ("i686-unknown-linux-gnu", i686_unknown_linux_gnu),
     ("i586-unknown-linux-gnu", i586_unknown_linux_gnu),
+    ("loongarch64-unknown-linux-gnu", loongarch64_unknown_linux_gnu),
     ("m68k-unknown-linux-gnu", m68k_unknown_linux_gnu),
     ("mips-unknown-linux-gnu", mips_unknown_linux_gnu),
     ("mips64-unknown-linux-gnuabi64", mips64_unknown_linux_gnuabi64),

compiler/rustc_trait_selection/src/solve/assembly/mod.rs

@@ -225,6 +225,11 @@ pub(super) trait GoalKind<'tcx>: TypeFoldable<TyCtxt<'tcx>> + Copy + Eq {
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
     ) -> QueryResult<'tcx>;
+
+    fn consider_builtin_transmute_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
 }
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {
@@ -373,6 +378,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             G::consider_builtin_discriminant_kind_candidate(self, goal)
         } else if lang_items.destruct_trait() == Some(trait_def_id) {
             G::consider_builtin_destruct_candidate(self, goal)
+        } else if lang_items.transmute_trait() == Some(trait_def_id) {
+            G::consider_builtin_transmute_candidate(self, goal)
         } else {
             Err(NoSolution)
         };

compiler/rustc_trait_selection/src/solve/eval_ctxt.rs

@@ -639,4 +639,25 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
         crate::traits::wf::unnormalized_obligations(self.infcx, param_env, arg)
             .map(|obligations| obligations.into_iter().map(|obligation| obligation.into()))
     }
+
+    pub(super) fn is_transmutable(
+        &self,
+        src_and_dst: rustc_transmute::Types<'tcx>,
+        scope: Ty<'tcx>,
+        assume: rustc_transmute::Assume,
+    ) -> Result<Certainty, NoSolution> {
+        // FIXME(transmutability): This really should be returning nested goals for `Answer::If*`
+        match rustc_transmute::TransmuteTypeEnv::new(self.infcx).is_transmutable(
+            ObligationCause::dummy(),
+            ty::Binder::dummy(src_and_dst),
+            scope,
+            assume,
+        ) {
+            rustc_transmute::Answer::Yes => Ok(Certainty::Yes),
+            rustc_transmute::Answer::No(_)
+            | rustc_transmute::Answer::IfTransmutable { .. }
+            | rustc_transmute::Answer::IfAll(_)
+            | rustc_transmute::Answer::IfAny(_) => Err(NoSolution),
+        }
+    }
 }

compiler/rustc_trait_selection/src/solve/project_goals.rs

@@ -524,6 +524,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
     ) -> QueryResult<'tcx> {
         bug!("`Destruct` does not have an associated type: {:?}", goal);
     }
+
+    fn consider_builtin_transmute_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("`BikeshedIntrinsicFrom` does not have an associated type: {:?}", goal)
+    }
 }
 
 /// This behavior is also implemented in `rustc_ty_utils` and in the old `project` code.

compiler/rustc_trait_selection/src/solve/trait_goals.rs

@@ -598,6 +598,35 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
             Err(NoSolution)
         }
     }
+
+    fn consider_builtin_transmute_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        // `rustc_transmute` does not have support for type or const params
+        if goal.has_non_region_placeholders() {
+            return Err(NoSolution);
+        }
+
+        // Erase regions because we compute layouts in `rustc_transmute`,
+        // which will ICE for region vars.
+        let substs = ecx.tcx().erase_regions(goal.predicate.trait_ref.substs);
+
+        let Some(assume) = rustc_transmute::Assume::from_const(
+            ecx.tcx(),
+            goal.param_env,
+            substs.const_at(3),
+        ) else {
+            return Err(NoSolution);
+        };
+
+        let certainty = ecx.is_transmutable(
+            rustc_transmute::Types { dst: substs.type_at(0), src: substs.type_at(1) },
+            substs.type_at(2),
+            assume,
+        )?;
+        ecx.evaluate_added_goals_and_make_canonical_response(certainty)
+    }
 }
 
 impl<'tcx> EvalCtxt<'_, 'tcx> {

config.example.toml

@@ -88,7 +88,7 @@ changelog-seen = 2
 # the resulting rustc being unable to compile for the disabled architectures.
 #
 # To add support for new targets, see https://rustc-dev-guide.rust-lang.org/building/new-target.html.
-#targets = "AArch64;ARM;BPF;Hexagon;MSP430;Mips;NVPTX;PowerPC;RISCV;Sparc;SystemZ;WebAssembly;X86"
+#targets = "AArch64;ARM;BPF;Hexagon;LoongArch;MSP430;Mips;NVPTX;PowerPC;RISCV;Sparc;SystemZ;WebAssembly;X86"
 
 # LLVM experimental targets to build support for. These targets are specified in
 # the same format as above, but since these targets are experimental, they are
@@ -257,7 +257,7 @@ changelog-seen = 2
 #python = "python"
 
 # The path to the REUSE executable to use. Note that REUSE is not required in
-# most cases, as our tooling relies on a cached (and shrinked) copy of the
+# most cases, as our tooling relies on a cached (and shrunk) copy of the
 # REUSE output present in the git repository and in our source tarballs.
 #
 # REUSE is only needed if your changes caused the overall licensing of the

library/core/src/macros/mod.rs

@@ -712,8 +712,8 @@ macro_rules! unimplemented {
 
 /// Indicates unfinished code.
 ///
-/// This can be useful if you are prototyping and are just looking to have your
-/// code typecheck.
+/// This can be useful if you are prototyping and just
+/// want a placeholder to let your code pass type analysis.
 ///
 /// The difference between [`unimplemented!`] and `todo!` is that while `todo!` conveys
 /// an intent of implementing the functionality later and the message is "not yet

library/std/src/env.rs

@@ -236,21 +236,14 @@ fn _var(key: &OsStr) -> Result<String, VarError> {
 }
 
 /// Fetches the environment variable `key` from the current process, returning
-/// [`None`] if the variable isn't set or there's another error.
+/// [`None`] if the variable isn't set or if there is another error.
 ///
-/// Note that the method will not check if the environment variable
-/// is valid Unicode. If you want to have an error on invalid UTF-8,
-/// use the [`var`] function instead.
-///
-/// # Errors
-///
-/// This function returns an error if the environment variable isn't set.
-///
-/// This function may return an error if the environment variable's name contains
+/// It may return `None` if the environment variable's name contains
 /// the equal sign character (`=`) or the NUL character.
 ///
-/// This function may return an error if the environment variable's value contains
-/// the NUL character.
+/// Note that this function will not check if the environment variable
+/// is valid Unicode. If you want to have an error on invalid UTF-8,
+/// use the [`var`] function instead.
 ///
 /// # Examples
 ///
@@ -895,6 +888,7 @@ pub mod consts {
     /// - x86_64
     /// - arm
     /// - aarch64
+    /// - loongarch64
     /// - m68k
     /// - mips
     /// - mips64

library/std/src/os/linux/raw.rs

@@ -231,6 +231,7 @@ mod arch {
 }
 
 #[cfg(any(
+    target_arch = "loongarch64",
     target_arch = "mips64",
     target_arch = "s390x",
     target_arch = "sparc64",

library/std/src/personality/gcc.rs

@@ -77,6 +77,9 @@ const UNWIND_DATA_REG: (i32, i32) = (0, 1); // R0, R1
 #[cfg(any(target_arch = "riscv64", target_arch = "riscv32"))]
 const UNWIND_DATA_REG: (i32, i32) = (10, 11); // x10, x11
 
+#[cfg(target_arch = "loongarch64")]
+const UNWIND_DATA_REG: (i32, i32) = (4, 5); // a0, a1
+
 // The following code is based on GCC's C and C++ personality routines.  For reference, see:
 // https://github.com/gcc-mirror/gcc/blob/master/libstdc++-v3/libsupc++/eh_personality.cc
 // https://github.com/gcc-mirror/gcc/blob/trunk/libgcc/unwind-c.c

library/std/src/sys/common/alloc.rs

@@ -22,6 +22,7 @@ pub const MIN_ALIGN: usize = 8;
 #[cfg(any(
     target_arch = "x86_64",
     target_arch = "aarch64",
+    target_arch = "loongarch64",
     target_arch = "mips64",
     target_arch = "s390x",
     target_arch = "sparc64",

library/std/src/sys/solid/net.rs

@@ -2,7 +2,7 @@ use super::abi;
 use crate::{
     cmp,
     ffi::CStr,
-    io::{self, ErrorKind, IoSlice, IoSliceMut},
+    io::{self, BorrowedBuf, BorrowedCursor, ErrorKind, IoSlice, IoSliceMut},
     mem,
     net::{Shutdown, SocketAddr},
     ptr, str,
@@ -294,19 +294,30 @@ impl Socket {
         self.0.duplicate().map(Socket)
     }
 
-    fn recv_with_flags(&self, buf: &mut [u8], flags: c_int) -> io::Result<usize> {
+    fn recv_with_flags(&self, mut buf: BorrowedCursor<'_>, flags: c_int) -> io::Result<()> {
         let ret = cvt(unsafe {
-            netc::recv(self.0.raw(), buf.as_mut_ptr() as *mut c_void, buf.len(), flags)
+            netc::recv(self.0.raw(), buf.as_mut().as_mut_ptr().cast(), buf.capacity(), flags)
         })?;
-        Ok(ret as usize)
+        unsafe {
+            buf.advance(ret as usize);
+        }
+        Ok(())
     }
 
     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
-        self.recv_with_flags(buf, 0)
+        let mut buf = BorrowedBuf::from(buf);
+        self.recv_with_flags(buf.unfilled(), 0)?;
+        Ok(buf.len())
     }
 
     pub fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
-        self.recv_with_flags(buf, MSG_PEEK)
+        let mut buf = BorrowedBuf::from(buf);
+        self.recv_with_flags(buf.unfilled(), MSG_PEEK)?;
+        Ok(buf.len())
+    }
+
+    pub fn read_buf(&self, buf: BorrowedCursor<'_>) -> io::Result<()> {
+        self.recv_with_flags(buf, 0)
     }
 
     pub fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {

library/unwind/src/libunwind.rs

@@ -75,6 +75,9 @@ pub const unwinder_private_data_size: usize = 20;
 #[cfg(all(target_arch = "hexagon", target_os = "linux"))]
 pub const unwinder_private_data_size: usize = 35;
 
+#[cfg(target_arch = "loongarch64")]
+pub const unwinder_private_data_size: usize = 2;
+
 #[repr(C)]
 pub struct _Unwind_Exception {
     pub exception_class: _Unwind_Exception_Class,

src/bootstrap/bootstrap.py

@@ -304,6 +304,7 @@ def default_build_triple(verbose):
         'i486': 'i686',
         'i686': 'i686',
         'i786': 'i686',
+        'loongarch64': 'loongarch64',
         'm68k': 'm68k',
         'powerpc': 'powerpc',
         'powerpc64': 'powerpc64',

src/bootstrap/channel.rs

@@ -139,7 +139,7 @@ pub fn read_commit_info_file(root: &Path) -> Option<Info> {
                 sha: sha.to_owned(),
                 short_sha: short_sha.to_owned(),
             },
-            _ => panic!("the `git-comit-info` file is malformed"),
+            _ => panic!("the `git-commit-info` file is malformed"),
         };
         Some(info)
     } else {

src/bootstrap/compile.rs

@@ -83,11 +83,11 @@ impl Step for Std {
         let target = self.target;
         let compiler = self.compiler;
 
-        // These artifacts were already copied (in `impl Step for Sysroot`).
-        // Don't recompile them.
+        // When using `download-rustc`, we already have artifacts for the host available
+        // (they were copied in `impl Step for Sysroot`). Don't recompile them.
         // NOTE: the ABI of the beta compiler is different from the ABI of the downloaded compiler,
         // so its artifacts can't be reused.
-        if builder.download_rustc() && compiler.stage != 0 {
+        if builder.download_rustc() && compiler.stage != 0 && target == builder.build.build {
             return;
         }
 

src/bootstrap/lib.rs

@@ -129,7 +129,8 @@ const EXTRA_CHECK_CFGS: &[(Option<Mode>, &'static str, Option<&[&'static str]>)]
     /* Extra values not defined in the built-in targets yet, but used in std */
     (Some(Mode::Std), "target_env", Some(&["libnx"])),
     // (Some(Mode::Std), "target_os", Some(&[])),
-    (Some(Mode::Std), "target_arch", Some(&["asmjs", "spirv", "nvptx", "xtensa"])),
+    // #[cfg(bootstrap)] loongarch64
+    (Some(Mode::Std), "target_arch", Some(&["asmjs", "spirv", "nvptx", "xtensa", "loongarch64"])),
     /* Extra names used by dependencies */
     // FIXME: Used by serde_json, but we should not be triggering on external dependencies.
     (Some(Mode::Rustc), "no_btreemap_remove_entry", None),

src/bootstrap/llvm.rs

@@ -291,7 +291,7 @@ impl Step for Llvm {
         let llvm_targets = match &builder.config.llvm_targets {
             Some(s) => s,
             None => {
-                "AArch64;ARM;BPF;Hexagon;MSP430;Mips;NVPTX;PowerPC;RISCV;\
+                "AArch64;ARM;BPF;Hexagon;LoongArch;MSP430;Mips;NVPTX;PowerPC;RISCV;\
                      Sparc;SystemZ;WebAssembly;X86"
             }
         };