Check that target features required by LLVM intrinsics are enabled

src/helpers.rs

@@ -1063,6 +1063,24 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             _ => span_bug!(this.cur_span(), "unexpected type: {ty:?}"),
         }
     }
+
+    /// Checks that target feature `target_feature` is enabled.
+    ///
+    /// If not enabled, emits an UB error that states that the feature is
+    /// required by `intrinsic`.
+    fn expect_target_feature_for_intrinsic(
+        &self,
+        intrinsic: Symbol,
+        target_feature: Symbol,
+    ) -> InterpResult<'tcx, ()> {
+        let this = self.eval_context_ref();
+        if !this.tcx.sess.unstable_target_features.contains(&target_feature) {
+            throw_ub_format!(
+                "attempted to call intrinsic `{intrinsic}` that requires missing {target_feature} target feature"
+            );
+        }
+        Ok(())
+    }
 }
 
 impl<'mir, 'tcx> MiriMachine<'mir, 'tcx> {

src/shims/foreign_items.rs

@@ -1008,9 +1008,11 @@ trait EvalContextExtPriv<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
             "llvm.arm.hint" if this.tcx.sess.target.arch == "arm" => {
                 let [arg] = this.check_shim(abi, Abi::Unadjusted, link_name, args)?;
                 let arg = this.read_scalar(arg)?.to_i32()?;
+                // Note that different arguments might have different target feature requirements.
                 match arg {
                     // YIELD
                     1 => {
+                        this.expect_target_feature_for_intrinsic(link_name, Symbol::intern("v6"))?;
                         this.yield_active_thread();
                     }
                     _ => {

src/shims/x86/aesni.rs

@@ -18,6 +18,7 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
         dest: &PlaceTy<'tcx, Provenance>,
     ) -> InterpResult<'tcx, EmulateForeignItemResult> {
         let this = self.eval_context_mut();
+        this.expect_target_feature_for_intrinsic(link_name, Symbol::intern("aes"))?;
         // Prefix should have already been checked.
         let unprefixed_name = link_name.as_str().strip_prefix("llvm.x86.aesni.").unwrap();
 

src/shims/x86/mod.rs

@@ -1,5 +1,5 @@
 use rustc_middle::mir;
-use rustc_span::Symbol;
+use rustc_span::{sym, Symbol};
 use rustc_target::abi::Size;
 use rustc_target::spec::abi::Abi;
 
@@ -164,7 +164,11 @@ enum FloatBinOp {
 impl FloatBinOp {
     /// Convert from the `imm` argument used to specify the comparison
     /// operation in intrinsics such as `llvm.x86.sse.cmp.ss`.
-    fn cmp_from_imm(imm: i8, intrinsic: &str) -> InterpResult<'_, Self> {
+    fn cmp_from_imm<'tcx>(
+        this: &crate::MiriInterpCx<'_, 'tcx>,
+        imm: i8,
+        intrinsic: Symbol,
+    ) -> InterpResult<'tcx, Self> {
         // Only bits 0..=4 are used, remaining should be zero.
         if imm & !0b1_1111 != 0 {
             throw_unsup_format!("invalid `imm` parameter of {intrinsic}: 0x{imm:x}");
@@ -174,7 +178,7 @@ impl FloatBinOp {
         // Bits 0..=2 specifies the operation.
         // `gt` indicates the result to be returned when the LHS is strictly
         // greater than the RHS, and so on.
-        let (gt, lt, eq, unord) = match imm & 0b111 {
+        let (gt, lt, eq, mut unord) = match imm & 0b111 {
             // Equal
             0x0 => (false, false, true, false),
             // Less-than
@@ -194,7 +198,10 @@ impl FloatBinOp {
             _ => unreachable!(),
         };
         // When bit 3 is 1 (only possible in AVX), unord is toggled.
-        let unord = unord ^ (imm & 0b1000 != 0);
+        if imm & 0b1000 != 0 {
+            this.expect_target_feature_for_intrinsic(intrinsic, sym::avx)?;
+            unord = !unord;
+        }
         Ok(Self::Cmp { gt, lt, eq, unord })
     }
 }

src/shims/x86/sse.rs

@@ -1,6 +1,6 @@
 use rustc_apfloat::{ieee::Single, Float as _};
 use rustc_middle::mir;
-use rustc_span::Symbol;
+use rustc_span::{sym, Symbol};
 use rustc_target::spec::abi::Abi;
 
 use rand::Rng as _;
@@ -21,6 +21,7 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
         dest: &PlaceTy<'tcx, Provenance>,
     ) -> InterpResult<'tcx, EmulateForeignItemResult> {
         let this = self.eval_context_mut();
+        this.expect_target_feature_for_intrinsic(link_name, sym::sse)?;
         // Prefix should have already been checked.
         let unprefixed_name = link_name.as_str().strip_prefix("llvm.x86.sse.").unwrap();
         // All these intrinsics operate on 128-bit (f32x4) SIMD vectors unless stated otherwise.
@@ -107,10 +108,8 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
                 let [left, right, imm] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 
-                let which = FloatBinOp::cmp_from_imm(
-                    this.read_scalar(imm)?.to_i8()?,
-                    "llvm.x86.sse.cmp.ss",
-                )?;
+                let which =
+                    FloatBinOp::cmp_from_imm(this, this.read_scalar(imm)?.to_i8()?, link_name)?;
 
                 bin_op_simd_float_first::<Single>(this, which, left, right, dest)?;
             }
@@ -126,10 +125,8 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
                 let [left, right, imm] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 
-                let which = FloatBinOp::cmp_from_imm(
-                    this.read_scalar(imm)?.to_i8()?,
-                    "llvm.x86.sse.cmp.ps",
-                )?;
+                let which =
+                    FloatBinOp::cmp_from_imm(this, this.read_scalar(imm)?.to_i8()?, link_name)?;
 
                 bin_op_simd_float_all::<Single>(this, which, left, right, dest)?;
             }

src/shims/x86/sse2.rs

@@ -20,6 +20,7 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
         dest: &PlaceTy<'tcx, Provenance>,
     ) -> InterpResult<'tcx, EmulateForeignItemResult> {
         let this = self.eval_context_mut();
+        this.expect_target_feature_for_intrinsic(link_name, Symbol::intern("sse2"))?;
         // Prefix should have already been checked.
         let unprefixed_name = link_name.as_str().strip_prefix("llvm.x86.sse2.").unwrap();
 
@@ -473,10 +474,8 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
                 let [left, right, imm] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 
-                let which = FloatBinOp::cmp_from_imm(
-                    this.read_scalar(imm)?.to_i8()?,
-                    "llvm.x86.sse2.cmp.sd",
-                )?;
+                let which =
+                    FloatBinOp::cmp_from_imm(this, this.read_scalar(imm)?.to_i8()?, link_name)?;
 
                 bin_op_simd_float_first::<Double>(this, which, left, right, dest)?;
             }
@@ -492,10 +491,8 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
                 let [left, right, imm] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 
-                let which = FloatBinOp::cmp_from_imm(
-                    this.read_scalar(imm)?.to_i8()?,
-                    "llvm.x86.sse2.cmp.pd",
-                )?;
+                let which =
+                    FloatBinOp::cmp_from_imm(this, this.read_scalar(imm)?.to_i8()?, link_name)?;
 
                 bin_op_simd_float_all::<Double>(this, which, left, right, dest)?;
             }

src/shims/x86/sse3.rs

@@ -18,6 +18,7 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
         dest: &PlaceTy<'tcx, Provenance>,
     ) -> InterpResult<'tcx, EmulateForeignItemResult> {
         let this = self.eval_context_mut();
+        this.expect_target_feature_for_intrinsic(link_name, Symbol::intern("sse3"))?;
         // Prefix should have already been checked.
         let unprefixed_name = link_name.as_str().strip_prefix("llvm.x86.sse3.").unwrap();
 

src/shims/x86/sse41.rs

@@ -18,6 +18,7 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
         dest: &PlaceTy<'tcx, Provenance>,
     ) -> InterpResult<'tcx, EmulateForeignItemResult> {
         let this = self.eval_context_mut();
+        this.expect_target_feature_for_intrinsic(link_name, Symbol::intern("sse4.1"))?;
         // Prefix should have already been checked.
         let unprefixed_name = link_name.as_str().strip_prefix("llvm.x86.sse41.").unwrap();
 

src/shims/x86/ssse3.rs

@@ -18,6 +18,7 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
         dest: &PlaceTy<'tcx, Provenance>,
     ) -> InterpResult<'tcx, EmulateForeignItemResult> {
         let this = self.eval_context_mut();
+        this.expect_target_feature_for_intrinsic(link_name, Symbol::intern("ssse3"))?;
         // Prefix should have already been checked.
         let unprefixed_name = link_name.as_str().strip_prefix("llvm.x86.ssse3.").unwrap();