Make s390x non-clobber-only vector register support unstable

Author: taiki-e

compiler/rustc_ast_lowering/messages.ftl

@@ -152,6 +152,8 @@ ast_lowering_register2 = register `{$reg2_name}`
 
 ast_lowering_register_class_only_clobber =
     register class `{$reg_class_name}` can only be used as a clobber, not as an input or output
+ast_lowering_register_class_only_clobber_stable =
+    register class `{$reg_class_name}` can only be used as a clobber in stable
 
 ast_lowering_register_conflict =
     register `{$reg1_name}` conflicts with register `{$reg2_name}`

compiler/rustc_ast_lowering/src/asm.rs

@@ -17,7 +17,8 @@ use super::errors::{
     InlineAsmUnsupportedTarget, InvalidAbiClobberAbi, InvalidAsmTemplateModifierConst,
     InvalidAsmTemplateModifierLabel, InvalidAsmTemplateModifierRegClass,
     InvalidAsmTemplateModifierRegClassSub, InvalidAsmTemplateModifierSym, InvalidRegister,
-    InvalidRegisterClass, RegisterClassOnlyClobber, RegisterConflict,
+    InvalidRegisterClass, RegisterClassOnlyClobber, RegisterClassOnlyClobberStable,
+    RegisterConflict,
 };
 use crate::{
     AllowReturnTypeNotation, ImplTraitContext, ImplTraitPosition, ParamMode,
@@ -61,6 +62,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 .emit();
             }
         }
+        let allow_experimental_reg = self.tcx.features().asm_experimental_reg();
         if asm.options.contains(InlineAsmOptions::ATT_SYNTAX)
             && !matches!(asm_arch, Some(asm::InlineAsmArch::X86 | asm::InlineAsmArch::X86_64))
             && !self.tcx.sess.opts.actually_rustdoc
@@ -333,11 +335,29 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 // means that we disallow passing a value in/out of the asm and
                 // require that the operand name an explicit register, not a
                 // register class.
-                if reg_class.is_clobber_only(asm_arch.unwrap()) && !op.is_clobber() {
-                    self.dcx().emit_err(RegisterClassOnlyClobber {
-                        op_span: op_sp,
-                        reg_class_name: reg_class.name(),
-                    });
+                if reg_class.is_clobber_only(asm_arch.unwrap(), allow_experimental_reg)
+                    && !op.is_clobber()
+                {
+                    if allow_experimental_reg || reg_class.is_clobber_only(asm_arch.unwrap(), true)
+                    {
+                        // always clobber-only
+                        self.dcx().emit_err(RegisterClassOnlyClobber {
+                            op_span: op_sp,
+                            reg_class_name: reg_class.name(),
+                        });
+                    } else {
+                        // clobber-only in stable
+                        self.tcx
+                            .sess
+                            .create_feature_err(
+                                RegisterClassOnlyClobberStable {
+                                    op_span: op_sp,
+                                    reg_class_name: reg_class.name(),
+                                },
+                                sym::asm_experimental_reg,
+                            )
+                            .emit();
+                    }
                     continue;
                 }
 

compiler/rustc_ast_lowering/src/errors.rs

@@ -279,6 +279,14 @@ pub(crate) struct RegisterClassOnlyClobber {
     pub reg_class_name: Symbol,
 }
 
+#[derive(Diagnostic)]
+#[diag(ast_lowering_register_class_only_clobber_stable)]
+pub(crate) struct RegisterClassOnlyClobberStable {
+    #[primary_span]
+    pub op_span: Span,
+    pub reg_class_name: Symbol,
+}
+
 #[derive(Diagnostic)]
 #[diag(ast_lowering_register_conflict)]
 pub(crate) struct RegisterConflict<'a> {

compiler/rustc_codegen_cranelift/src/inline_asm.rs

@@ -462,8 +462,12 @@ impl<'tcx> InlineAssemblyGenerator<'_, 'tcx> {
         let mut slots_output = vec![None; self.operands.len()];
 
         let new_slot_fn = |slot_size: &mut Size, reg_class: InlineAsmRegClass| {
-            let reg_size =
-                reg_class.supported_types(self.arch).iter().map(|(ty, _)| ty.size()).max().unwrap();
+            let reg_size = reg_class
+                .supported_types(self.arch, true)
+                .iter()
+                .map(|(ty, _)| ty.size())
+                .max()
+                .unwrap();
             let align = rustc_abi::Align::from_bytes(reg_size.bytes()).unwrap();
             let offset = slot_size.align_to(align);
             *slot_size = offset + reg_size;

compiler/rustc_codegen_gcc/src/asm.rs

@@ -186,7 +186,7 @@ impl<'a, 'gcc, 'tcx> AsmBuilderMethods<'tcx> for Builder<'a, 'gcc, 'tcx> {
                             // `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).iter().any(
+                                reg.reg_class().supported_types(asm_arch, true).iter().any(
                                     |&(_, feature)| {
                                         if let Some(feature) = feature {
                                             self.tcx

compiler/rustc_codegen_llvm/src/asm.rs

@@ -45,7 +45,7 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
             match *op {
                 InlineAsmOperandRef::Out { reg, late, place } => {
                     let is_target_supported = |reg_class: InlineAsmRegClass| {
-                        for &(_, feature) in reg_class.supported_types(asm_arch) {
+                        for &(_, feature) in reg_class.supported_types(asm_arch, true) {
                             if let Some(feature) = feature {
                                 if self
                                     .tcx
@@ -85,7 +85,7 @@ impl<'ll, 'tcx> AsmBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
                         }
                         continue;
                     } else if !is_target_supported(reg.reg_class())
-                        || reg.reg_class().is_clobber_only(asm_arch)
+                        || reg.reg_class().is_clobber_only(asm_arch, true)
                     {
                         // We turn discarded outputs into clobber constraints
                         // if the target feature needed by the register class is

compiler/rustc_feature/src/unstable.rs

@@ -376,6 +376,8 @@ declare_features! (
     (unstable, arbitrary_self_types_pointers, "1.83.0", Some(44874)),
     /// Enables experimental inline assembly support for additional architectures.
     (unstable, asm_experimental_arch, "1.58.0", Some(93335)),
+    /// Enables experimental register support in inline assembly.
+    (unstable, asm_experimental_reg, "CURRENT_RUSTC_VERSION", Some(133416)),
     /// Allows using `label` operands in inline assembly.
     (unstable, asm_goto, "1.78.0", Some(119364)),
     /// Allows the `may_unwind` option in inline assembly.

compiler/rustc_hir_analysis/messages.ftl

@@ -424,6 +424,9 @@ hir_analysis_recursive_generic_parameter = {$param_def_kind} `{$param_name}` is
 hir_analysis_redundant_lifetime_args = unnecessary lifetime parameter `{$victim}`
     .note = you can use the `{$candidate}` lifetime directly, in place of `{$victim}`
 
+hir_analysis_register_type_unstable =
+    type `{$ty}` cannot be used with this register class in stable
+
 hir_analysis_requires_note = the `{$trait_name}` impl for `{$ty}` requires that `{$error_predicate}`
 
 hir_analysis_return_type_notation_equality_bound =

compiler/rustc_hir_analysis/src/check/intrinsicck.rs

@@ -7,12 +7,14 @@ use rustc_hir::{self as hir, LangItem};
 use rustc_middle::bug;
 use rustc_middle::ty::{self, FloatTy, IntTy, Ty, TyCtxt, TypeVisitableExt, UintTy};
 use rustc_session::lint;
-use rustc_span::Symbol;
 use rustc_span::def_id::LocalDefId;
+use rustc_span::{Symbol, sym};
 use rustc_target::asm::{
     InlineAsmReg, InlineAsmRegClass, InlineAsmRegOrRegClass, InlineAsmType, ModifierInfo,
 };
 
+use crate::errors::RegisterTypeUnstable;
+
 pub struct InlineAsmCtxt<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     typing_env: ty::TypingEnv<'tcx>,
@@ -218,17 +220,29 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
         // Check the type against the list of types supported by the selected
         // register class.
         let asm_arch = self.tcx.sess.asm_arch.unwrap();
+        let allow_experimental_reg = self.tcx.features().asm_experimental_reg();
         let reg_class = reg.reg_class();
-        let supported_tys = reg_class.supported_types(asm_arch);
+        let supported_tys = reg_class.supported_types(asm_arch, allow_experimental_reg);
         let Some((_, feature)) = supported_tys.iter().find(|&&(t, _)| t == asm_ty) else {
-            let msg = format!("type `{ty}` cannot be used with this register class");
-            let mut err = self.tcx.dcx().struct_span_err(expr.span, msg);
-            let supported_tys: Vec<_> = supported_tys.iter().map(|(t, _)| t.to_string()).collect();
-            err.note(format!(
-                "register class `{}` supports these types: {}",
-                reg_class.name(),
-                supported_tys.join(", "),
-            ));
+            let mut err = if !allow_experimental_reg
+                && reg_class.supported_types(asm_arch, true).iter().any(|&(t, _)| t == asm_ty)
+            {
+                self.tcx.sess.create_feature_err(
+                    RegisterTypeUnstable { span: expr.span, ty },
+                    sym::asm_experimental_reg,
+                )
+            } else {
+                let msg = format!("type `{ty}` cannot be used with this register class");
+                let mut err = self.tcx.dcx().struct_span_err(expr.span, msg);
+                let supported_tys: Vec<_> =
+                    supported_tys.iter().map(|(t, _)| t.to_string()).collect();
+                err.note(format!(
+                    "register class `{}` supports these types: {}",
+                    reg_class.name(),
+                    supported_tys.join(", "),
+                ));
+                err
+            };
             if let Some(suggest) = reg_class.suggest_class(asm_arch, asm_ty) {
                 err.help(format!("consider using the `{}` register class instead", suggest.name()));
             }
@@ -313,6 +327,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
             self.tcx.dcx().delayed_bug("target architecture does not support asm");
             return;
         };
+        let allow_experimental_reg = self.tcx.features().asm_experimental_reg();
         for (idx, (op, op_sp)) in asm.operands.iter().enumerate() {
             // Validate register classes against currently enabled target
             // features. We check that at least one type is available for
@@ -352,7 +367,8 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
                     if let InlineAsmRegClass::Err = reg_class {
                         continue;
                     }
-                    for &(_, feature) in reg_class.supported_types(asm_arch) {
+                    for &(_, feature) in reg_class.supported_types(asm_arch, allow_experimental_reg)
+                    {
                         match feature {
                             Some(feature) => {
                                 if target_features.contains(&feature) {

compiler/rustc_hir_analysis/src/errors.rs

@@ -1685,3 +1685,11 @@ pub(crate) struct CmseEntryGeneric {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_register_type_unstable)]
+pub(crate) struct RegisterTypeUnstable<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub ty: Ty<'a>,
+}