Change codegen of LLVM intrinsics to be name-based, and add llvm linkage support for bf16(xN), i1xN and x86amx

compiler/rustc_codegen_gcc/src/type_of.rs

@@ -1,6 +1,6 @@
 use std::fmt::Write;
 
-use gccjit::{Struct, Type};
+use gccjit::{RValue, Struct, Type};
 use rustc_abi as abi;
 use rustc_abi::Primitive::*;
 use rustc_abi::{
@@ -373,7 +373,11 @@ impl<'gcc, 'tcx> LayoutTypeCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         unimplemented!();
     }
 
-    fn fn_decl_backend_type(&self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Type<'gcc> {
+    fn fn_decl_backend_type(
+        &self,
+        fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
+        _fn_ptr: RValue<'gcc>,
+    ) -> Type<'gcc> {
         // FIXME(antoyo): Should we do something with `FnAbiGcc::fn_attributes`?
         let FnAbiGcc { return_type, arguments_type, is_c_variadic, .. } = fn_abi.gcc_type(self);
         self.context.new_function_pointer_type(None, return_type, &arguments_type, is_c_variadic)

compiler/rustc_codegen_llvm/messages.ftl

@@ -3,12 +3,19 @@ codegen_llvm_autodiff_without_enable = using the autodiff feature requires -Z au
 codegen_llvm_copy_bitcode = failed to copy bitcode to object file: {$err}
 
 
+
 codegen_llvm_fixed_x18_invalid_arch = the `-Zfixed-x18` flag is not supported on the `{$arch}` architecture
 
 codegen_llvm_from_llvm_diag = {$message}
 
 codegen_llvm_from_llvm_optimization_diag = {$filename}:{$line}:{$column} {$pass_name} ({$kind}): {$message}
 
+codegen_llvm_intrinsic_signature_mismatch =
+    Intrinsic signature mismatch for `{$name}`: expected signature `{$llvm_fn_ty}`, found `{$rust_fn_ty}`
+
+codegen_llvm_intrinsic_wrong_arch =
+    Intrinsic `{$name}` cannot be used with target arch `{$target_arch}`
+
 codegen_llvm_load_bitcode = failed to load bitcode of module "{$name}"
 codegen_llvm_load_bitcode_with_llvm_err = failed to load bitcode of module "{$name}": {$llvm_err}
 

compiler/rustc_codegen_llvm/src/abi.rs

@@ -1,12 +1,13 @@
 use std::borrow::Borrow;
-use std::cmp;
+use std::{cmp, iter};
 
 use libc::c_uint;
 use rustc_abi::{
     ArmCall, BackendRepr, CanonAbi, HasDataLayout, InterruptKind, Primitive, Reg, RegKind, Size,
     X86Call,
 };
 use rustc_codegen_ssa::MemFlags;
+use rustc_codegen_ssa::common::TypeKind;
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
 use rustc_codegen_ssa::mir::place::{PlaceRef, PlaceValue};
 use rustc_codegen_ssa::traits::*;
@@ -22,7 +23,7 @@ use smallvec::SmallVec;
 
 use crate::attributes::{self, llfn_attrs_from_instance};
 use crate::builder::Builder;
-use crate::context::CodegenCx;
+use crate::context::{CodegenCx, GenericCx, SCx};
 use crate::llvm::{self, Attribute, AttributePlace};
 use crate::llvm_util;
 use crate::type_::Type;
@@ -306,8 +307,52 @@ impl<'ll, 'tcx> ArgAbiBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
     }
 }
 
+pub(crate) enum FunctionSignature<'ll> {
+    /// This is an LLVM intrinsic, the signature is obtained directly from LLVM, and **may not match the Rust signature**
+    LLVMSignature(llvm::Intrinsic, &'ll Type),
+    /// This is an LLVM intrinsic, but the signature is just the Rust signature.
+    /// FIXME: this should ideally not exist, we should be using the LLVM signature for all LLVM intrinsics
+    RustSignature(llvm::Intrinsic, &'ll Type),
+    /// FIXME: This shouldn't exist as well, but needed to get around autocast
+    NonMatchingSignature { intrinsic: llvm::Intrinsic, llvm_ty: &'ll Type, rust_ty: &'ll Type },
+    /// The name starts with `llvm.`, but can't obtain the intrinsic ID. May be invalid or upgradable
+    MaybeInvalid(&'ll Type),
+    /// Just the Rust signature
+    NotIntrinsic(&'ll Type),
+}
+
+impl<'ll> FunctionSignature<'ll> {
+    pub(crate) fn fn_ty(&self) -> &'ll Type {
+        match self {
+            FunctionSignature::LLVMSignature(_, fn_ty)
+            | FunctionSignature::RustSignature(_, fn_ty)
+            | FunctionSignature::MaybeInvalid(fn_ty)
+            | FunctionSignature::NotIntrinsic(fn_ty) => fn_ty,
+            FunctionSignature::NonMatchingSignature { rust_ty, .. } => rust_ty,
+        }
+    }
+
+    pub(crate) fn intrinsic(&self) -> Option<llvm::Intrinsic> {
+        match self {
+            FunctionSignature::RustSignature(intrinsic, _)
+            | FunctionSignature::LLVMSignature(intrinsic, _)
+            | FunctionSignature::NonMatchingSignature { intrinsic, .. } => Some(*intrinsic),
+            _ => None,
+        }
+    }
+}
+
 pub(crate) trait FnAbiLlvmExt<'ll, 'tcx> {
-    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
+    fn llvm_return_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
+    fn llvm_argument_types(&self, cx: &CodegenCx<'ll, 'tcx>) -> Vec<&'ll Type>;
+    /// When `do_verify` is set, this function performs checks for the signature of LLVM intrinsics
+    /// and emits a fatal error if it doesn't match. These checks are important,but somewhat expensive
+    /// So they are only used at function definitions, not at callsites
+    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>, name: &[u8]) -> FunctionSignature<'ll>;
+    /// The normal Rust signature for this
+    fn rust_signature(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
+    /// **If this function is an LLVM intrinsic** checks if the LLVM signature provided matches with this
+    fn verify_intrinsic_signature(&self, cx: &CodegenCx<'ll, 'tcx>, llvm_ty: &'ll Type) -> bool;
     fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
     fn llvm_cconv(&self, cx: &CodegenCx<'ll, 'tcx>) -> llvm::CallConv;
 
@@ -320,30 +365,68 @@ pub(crate) trait FnAbiLlvmExt<'ll, 'tcx> {
     );
 
     /// Apply attributes to a function call.
-    fn apply_attrs_callsite(&self, bx: &mut Builder<'_, 'll, 'tcx>, callsite: &'ll Value);
+    fn apply_attrs_callsite(
+        &self,
+        bx: &mut Builder<'_, 'll, 'tcx>,
+        callsite: &'ll Value,
+        llfn: &'ll Value,
+    );
+}
+
+impl<'ll, CX: Borrow<SCx<'ll>>> GenericCx<'ll, CX> {
+    pub(crate) fn equate_ty(&self, rust_ty: &'ll Type, llvm_ty: &'ll Type) -> bool {
+        if rust_ty == llvm_ty {
+            return true;
+        }
+
+        // Some LLVM intrinsics return **non-packed** structs, but they can't be mimicked from Rust
+        // due to auto field-alignment in non-packed structs (packed structs are represented in LLVM
+        // as, well, packed structs, so they won't match with those either)
+        if self.type_kind(llvm_ty) == TypeKind::Struct
+            && self.type_kind(rust_ty) == TypeKind::Struct
+        {
+            let rust_element_tys = self.struct_element_types(rust_ty);
+            let llvm_element_tys = self.struct_element_types(llvm_ty);
+
+            if rust_element_tys.len() != llvm_element_tys.len() {
+                return false;
+            }
+
+            iter::zip(rust_element_tys, llvm_element_tys).all(
+                |(rust_element_ty, llvm_element_ty)| {
+                    self.equate_ty(rust_element_ty, llvm_element_ty)
+                },
+            )
+        } else {
+            false
+        }
+    }
 }
 
 impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
-    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
+    fn llvm_return_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
+        match &self.ret.mode {
+            PassMode::Ignore => cx.type_void(),
+            PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx),
+            PassMode::Cast { cast, pad_i32: _ } => cast.llvm_type(cx),
+            PassMode::Indirect { .. } => cx.type_void(),
+        }
+    }
+
+    fn llvm_argument_types(&self, cx: &CodegenCx<'ll, 'tcx>) -> Vec<&'ll Type> {
+        let indirect_return = matches!(self.ret.mode, PassMode::Indirect { .. });
+
         // Ignore "extra" args from the call site for C variadic functions.
         // Only the "fixed" args are part of the LLVM function signature.
         let args =
             if self.c_variadic { &self.args[..self.fixed_count as usize] } else { &self.args };
 
-        // This capacity calculation is approximate.
-        let mut llargument_tys = Vec::with_capacity(
-            self.args.len() + if let PassMode::Indirect { .. } = self.ret.mode { 1 } else { 0 },
-        );
+        let mut llargument_tys =
+            Vec::with_capacity(args.len() + if indirect_return { 1 } else { 0 });
 
-        let llreturn_ty = match &self.ret.mode {
-            PassMode::Ignore => cx.type_void(),
-            PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx),
-            PassMode::Cast { cast, pad_i32: _ } => cast.llvm_type(cx),
-            PassMode::Indirect { .. } => {
-                llargument_tys.push(cx.type_ptr());
-                cx.type_void()
-            }
-        };
+        if indirect_return {
+            llargument_tys.push(cx.type_ptr());
+        }
 
         for arg in args {
             // Note that the exact number of arguments pushed here is carefully synchronized with
@@ -390,10 +473,66 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
             llargument_tys.push(llarg_ty);
         }
 
+        llargument_tys
+    }
+
+    fn verify_intrinsic_signature(&self, cx: &CodegenCx<'ll, 'tcx>, llvm_fn_ty: &'ll Type) -> bool {
+        let rust_return_ty = self.llvm_return_type(cx);
+        let rust_argument_tys = self.llvm_argument_types(cx);
+
+        let llvm_return_ty = cx.get_return_type(llvm_fn_ty);
+        let llvm_argument_tys = cx.func_params_types(llvm_fn_ty);
+        let llvm_is_variadic = cx.func_is_variadic(llvm_fn_ty);
+
+        if self.c_variadic != llvm_is_variadic || rust_argument_tys.len() != llvm_argument_tys.len()
+        {
+            return false;
+        }
+
+        iter::once((rust_return_ty, llvm_return_ty))
+            .chain(iter::zip(rust_argument_tys, llvm_argument_tys))
+            .all(|(rust_ty, llvm_ty)| cx.equate_ty(rust_ty, llvm_ty))
+    }
+
+    fn rust_signature(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
+        let return_ty = self.llvm_return_type(cx);
+        let argument_tys = self.llvm_argument_types(cx);
+
         if self.c_variadic {
-            cx.type_variadic_func(&llargument_tys, llreturn_ty)
+            cx.type_variadic_func(&argument_tys, return_ty)
+        } else {
+            cx.type_func(&argument_tys, return_ty)
+        }
+    }
+
+    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>, name: &[u8]) -> FunctionSignature<'ll> {
+        if name.starts_with(b"llvm.") {
+            if let Some(intrinsic) = llvm::Intrinsic::lookup(name) {
+                if !intrinsic.is_overloaded() {
+                    // FIXME: also do this for overloaded intrinsics
+                    let llvm_ty = intrinsic.get_type(cx.llcx, &[]);
+                    if self.verify_intrinsic_signature(cx, llvm_ty) {
+                        FunctionSignature::LLVMSignature(intrinsic, llvm_ty)
+                    } else {
+                        FunctionSignature::NonMatchingSignature {
+                            intrinsic,
+                            llvm_ty,
+                            rust_ty: self.rust_signature(cx),
+                        }
+                    }
+                } else {
+                    FunctionSignature::RustSignature(intrinsic, self.rust_signature(cx))
+                }
+            } else {
+                // it's one of 2 cases,
+                // - either the base name is invalid
+                // - it has been superseded by something else, so the intrinsic was removed entirely
+                // to check for upgrades, we need the `llfn`, so we defer it for now
+
+                FunctionSignature::MaybeInvalid(self.rust_signature(cx))
+            }
         } else {
-            cx.type_func(&llargument_tys, llreturn_ty)
+            FunctionSignature::NotIntrinsic(self.rust_signature(cx))
         }
     }
 
@@ -545,7 +684,17 @@ impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
         }
     }
 
-    fn apply_attrs_callsite(&self, bx: &mut Builder<'_, 'll, 'tcx>, callsite: &'ll Value) {
+    fn apply_attrs_callsite(
+        &self,
+        bx: &mut Builder<'_, 'll, 'tcx>,
+        callsite: &'ll Value,
+        llfn: &'ll Value,
+    ) {
+        // Don't apply any attributes to LLVM intrinsics, they will be applied by AutoUpgrade
+        if llvm::get_value_name(llfn).starts_with(b"llvm.") {
+            return;
+        }
+
         let mut func_attrs = SmallVec::<[_; 2]>::new();
         if self.ret.layout.is_uninhabited() {
             func_attrs.push(llvm::AttributeKind::NoReturn.create_attr(bx.cx.llcx));