Auto merge of #143161 - GuillaumeGomez:subtree-update_cg_gcc_2025-06-28, r=GuillaumeGomez

GCC backend subtree update

cc `@antoyo`

r? ghost

Author: bors

compiler/rustc_codegen_gcc/build_system/src/abi_test.rs

@@ -0,0 +1,65 @@
+use std::ffi::OsStr;
+use std::path::Path;
+
+use crate::utils::run_command_with_output;
+
+fn show_usage() {
+    println!(
+        r#"
+`abi-test` command help:
+    --help                 : Show this help"#
+    );
+}
+
+pub fn run() -> Result<(), String> {
+    let mut args = std::env::args().skip(2);
+    // FractalFir: In the future, I'd like to add some more subcommands / options.
+    // So, this loop ought to stay for that purpose. It should also stay as a while loop(to parse args)
+    #[allow(clippy::never_loop, clippy::while_let_on_iterator)]
+    while let Some(arg) = args.next() {
+        match arg.as_str() {
+            "--help" => {
+                show_usage();
+                return Ok(());
+            }
+            _ => return Err(format!("Unknown option {arg:?}")),
+        }
+    }
+    // Ensure that we have a cloned version of abi-cafe on hand.
+    crate::utils::git_clone(
+        "https://github.com/Gankra/abi-cafe.git",
+        Some("clones/abi-cafe".as_ref()),
+        true,
+    )
+    .map_err(|err| (format!("Git clone failed with message: {err:?}!")))?;
+    // Configure abi-cafe to use the exact same rustc version we use - this is crucial.
+    // Otherwise, the concept of ABI compatibility becomes meanignless.
+    std::fs::copy("rust-toolchain", "clones/abi-cafe/rust-toolchain")
+        .expect("Could not copy toolchain configs!");
+    // Get the backend path.
+    // We will use the *debug* build of the backend - it has more checks enabled.
+    let backend_path = std::path::absolute("target/debug/librustc_codegen_gcc.so").unwrap();
+    let backend_arg = format!("--add-rustc-codegen-backend=cg_gcc:{}", backend_path.display());
+    // Run ABI cafe using cargo.
+    let cmd: &[&dyn AsRef<OsStr>] = &[
+        &"cargo",
+        &"run",
+        &"--release",
+        &"--",
+        &backend_arg,
+        // Test rust-LLVM to Rust-GCC calls
+        &"--pairs",
+        &"rustc_calls_cg_gcc",
+        &"--pairs",
+        &"cg_gcc_calls_rustc",
+        // Test Rust-GCC to C calls
+        &"--pairs",
+        &"cg_gcc_calls_c",
+        &"--pairs",
+        &"c_calls_cg_gcc",
+    ];
+    // Run ABI cafe.
+    run_command_with_output(cmd, Some(Path::new("clones/abi-cafe")))?;
+
+    Ok(())
+}

compiler/rustc_codegen_gcc/build_system/src/main.rs

@@ -1,5 +1,6 @@
 use std::{env, process};
 
+mod abi_test;
 mod build;
 mod clean;
 mod clone_gcc;
@@ -12,7 +13,6 @@ mod rust_tools;
 mod rustc_info;
 mod test;
 mod utils;
-
 const BUILD_DIR: &str = "build";
 
 macro_rules! arg_error {
@@ -44,7 +44,8 @@ Commands:
         info      : Displays information about the build environment and project configuration.
         clone-gcc : Clones the GCC compiler from a specified source.
         fmt       : Runs rustfmt
-        fuzz      : Fuzzes `cg_gcc` using rustlantis"
+        fuzz      : Fuzzes `cg_gcc` using rustlantis
+        abi-test   : Runs the abi-cafe test suite on the codegen, checking for ABI compatibility with LLVM"
     );
 }
 
@@ -59,6 +60,7 @@ pub enum Command {
     Info,
     Fmt,
     Fuzz,
+    AbiTest,
 }
 
 fn main() {
@@ -77,6 +79,7 @@ fn main() {
         Some("test") => Command::Test,
         Some("info") => Command::Info,
         Some("clone-gcc") => Command::CloneGcc,
+        Some("abi-test") => Command::AbiTest,
         Some("fmt") => Command::Fmt,
         Some("fuzz") => Command::Fuzz,
         Some("--help") => {
@@ -102,6 +105,7 @@ fn main() {
         Command::CloneGcc => clone_gcc::run(),
         Command::Fmt => fmt::run(),
         Command::Fuzz => fuzz::run(),
+        Command::AbiTest => abi_test::run(),
     } {
         eprintln!("Command failed to run: {e}");
         process::exit(1);

compiler/rustc_codegen_gcc/build_system/src/test.rs

@@ -738,14 +738,7 @@ fn test_libcore(env: &Env, args: &TestArg) -> Result<(), String> {
     let path = get_sysroot_dir().join("sysroot_src/library/coretests");
     let _ = remove_dir_all(path.join("target"));
     // TODO(antoyo): run in release mode when we fix the failures.
-    // TODO(antoyo): remove the --skip f16::test_total_cmp when this issue is fixed:
-    // https://github.com/rust-lang/rust/issues/141503
-    run_cargo_command(
-        &[&"test", &"--", &"--skip", &"f16::test_total_cmp"],
-        Some(&path),
-        env,
-        args,
-    )?;
+    run_cargo_command(&[&"test"], Some(&path), env, args)?;
     Ok(())
 }
 

compiler/rustc_codegen_gcc/patches/0001-Pin-compiler_builtins-to-0.1.160.patch

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2025-05-21"
+channel = "nightly-2025-06-02"
 components = ["rust-src", "rustc-dev", "llvm-tools-preview"]

compiler/rustc_codegen_gcc/rust-toolchain

@@ -520,8 +520,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
         self.block
     }
 
-    fn append_block(cx: &'a CodegenCx<'gcc, 'tcx>, func: RValue<'gcc>, name: &str) -> Block<'gcc> {
-        let func = cx.rvalue_as_function(func);
+    fn append_block(_: &'a CodegenCx<'gcc, 'tcx>, func: Function<'gcc>, name: &str) -> Block<'gcc> {
         func.new_block(name)
     }
 
@@ -782,6 +781,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
                 return self.context.new_call(self.location, fmod, &[a, b]);
             }
             TypeKind::FP128 => {
+                // TODO(antoyo): use get_simple_function_f128_2args.
                 let f128_type = self.type_f128();
                 let fmodf128 = self.context.new_function(
                     None,
@@ -938,22 +938,36 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
     fn load(&mut self, pointee_ty: Type<'gcc>, ptr: RValue<'gcc>, align: Align) -> RValue<'gcc> {
         let block = self.llbb();
         let function = block.get_function();
+        // NOTE(FractalFir): In some cases, we *should* skip the call to get_aligned.
+        // For example, calling `get_aligned` on a i8 is pointless(since it can only be 1 aligned)
+        // Calling get_aligned on a `u128`/`i128` causes the attribute to become "stacked"
+        //
+        // From GCCs perspective:
+        // __int128_t  __attribute__((aligned(16)))  __attribute__((aligned(16)))
+        // and:
+        // __int128_t  __attribute__((aligned(16)))
+        // are 2 distinct, incompatible types.
+        //
+        // So, we skip the call to `get_aligned` in such a case. *Ideally*, we could do this for all the types,
+        // but the GCC APIs to facilitate this just aren't quite there yet.
+
+        // This checks that we only skip `get_aligned` on 128 bit ints if they have the correct alignment.
+        // Otherwise, this may be an under-aligned load, so we will still call get_aligned.
+        let mut can_skip_align = (pointee_ty == self.cx.u128_type
+            || pointee_ty == self.cx.i128_type)
+            && align == self.int128_align;
+        // We can skip the call to `get_aligned` for byte-sized types with alignment of 1.
+        can_skip_align = can_skip_align
+            || (pointee_ty == self.cx.u8_type || pointee_ty == self.cx.i8_type)
+                && align.bytes() == 1;
+        // Skip the call to `get_aligned` when possible.
+        let aligned_type =
+            if can_skip_align { pointee_ty } else { pointee_ty.get_aligned(align.bytes()) };
+
+        let ptr = self.context.new_cast(self.location, ptr, aligned_type.make_pointer());
         // NOTE: instead of returning the dereference here, we have to assign it to a variable in
         // the current basic block. Otherwise, it could be used in another basic block, causing a
         // dereference after a drop, for instance.
-        // FIXME(antoyo): this check that we don't call get_aligned() a second time on a type.
-        // Ideally, we shouldn't need to do this check.
-        // FractalFir: the `align == self.int128_align` check ensures we *do* call `get_aligned` if
-        // the alignment of a `u128`/`i128` is not the one mandated by the ABI. This ensures we handle
-        // under-aligned loads correctly.
-        let aligned_type = if (pointee_ty == self.cx.u128_type || pointee_ty == self.cx.i128_type)
-            && align == self.int128_align
-        {
-            pointee_ty
-        } else {
-            pointee_ty.get_aligned(align.bytes())
-        };
-        let ptr = self.context.new_cast(self.location, ptr, aligned_type.make_pointer());
         let deref = ptr.dereference(self.location).to_rvalue();
         let loaded_value = function.new_local(
             self.location,
@@ -1105,7 +1119,13 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
         // TODO(antoyo)
     }
 
-    fn store(&mut self, val: RValue<'gcc>, ptr: RValue<'gcc>, align: Align) -> RValue<'gcc> {
+    fn store(&mut self, mut val: RValue<'gcc>, ptr: RValue<'gcc>, align: Align) -> RValue<'gcc> {
+        if self.structs_as_pointer.borrow().contains(&val) {
+            // NOTE: hack to workaround a limitation of the rustc API: see comment on
+            // CodegenCx.structs_as_pointer
+            val = val.dereference(self.location).to_rvalue();
+        }
+
         self.store_with_flags(val, ptr, align, MemFlags::empty())
     }
 
@@ -1551,16 +1571,13 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
         aggregate_value
     }
 
-    fn set_personality_fn(&mut self, _personality: RValue<'gcc>) {
+    fn set_personality_fn(&mut self, _personality: Function<'gcc>) {
         #[cfg(feature = "master")]
-        {
-            let personality = self.rvalue_as_function(_personality);
-            self.current_func().set_personality_function(personality);
-        }
+        self.current_func().set_personality_function(_personality);
     }
 
     #[cfg(feature = "master")]
-    fn cleanup_landing_pad(&mut self, pers_fn: RValue<'gcc>) -> (RValue<'gcc>, RValue<'gcc>) {
+    fn cleanup_landing_pad(&mut self, pers_fn: Function<'gcc>) -> (RValue<'gcc>, RValue<'gcc>) {
         self.set_personality_fn(pers_fn);
 
         // NOTE: insert the current block in a variable so that a later call to invoke knows to
@@ -1581,7 +1598,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
     }
 
     #[cfg(not(feature = "master"))]
-    fn cleanup_landing_pad(&mut self, _pers_fn: RValue<'gcc>) -> (RValue<'gcc>, RValue<'gcc>) {
+    fn cleanup_landing_pad(&mut self, _pers_fn: Function<'gcc>) -> (RValue<'gcc>, RValue<'gcc>) {
         let value1 = self
             .current_func()
             .new_local(self.location, self.u8_type.make_pointer(), "landing_pad0")
@@ -1591,7 +1608,7 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
         (value1, value2)
     }
 
-    fn filter_landing_pad(&mut self, pers_fn: RValue<'gcc>) {
+    fn filter_landing_pad(&mut self, pers_fn: Function<'gcc>) {
         // TODO(antoyo): generate the correct landing pad
         self.cleanup_landing_pad(pers_fn);
     }

compiler/rustc_codegen_gcc/src/builder.rs

@@ -234,19 +234,6 @@ impl<'gcc, 'tcx> ConstCodegenMethods for CodegenCx<'gcc, 'tcx> {
         match cv {
             Scalar::Int(int) => {
                 let data = int.to_bits(layout.size(self));
-
-                // FIXME(antoyo): there's some issues with using the u128 code that follows, so hard-code
-                // the paths for floating-point values.
-                // TODO: Remove this code?
-                /*if ty == self.float_type {
-                    return self
-                        .context
-                        .new_rvalue_from_double(ty, f32::from_bits(data as u32) as f64);
-                }
-                if ty == self.double_type {
-                    return self.context.new_rvalue_from_double(ty, f64::from_bits(data as u64));
-                }*/
-
                 let value = self.const_uint_big(self.type_ix(bitsize), data);
                 let bytesize = layout.size(self).bytes();
                 if bitsize > 1 && ty.is_integral() && bytesize as u32 == ty.get_size() {