Fuzz multiple targets in cranelift-icache (#5482)

Fuzz additional targets in the cranelift-icache target. The list of targets fuzzed is controlled by the targets enabled in fuzz/Cargo.toml.

This PR also reworks how instruction disabling is done in function generator, moving the deny-list to a function to make the decision at runtime instead of compile time.

Cargo.lock

@@ -635,6 +635,7 @@ dependencies = [
  "arbitrary",
  "cranelift",
  "cranelift-native",
+ "target-lexicon",
 ]
 
 [[package]]

cranelift/codegen/src/isa/mod.rs

@@ -105,6 +105,11 @@ pub fn lookup(triple: Triple) -> Result<Builder, LookupError> {
     }
 }
 
+/// The string names of all the supported, but possibly not enabled, architectures. The elements of
+/// this slice are suitable to be passed to the [lookup_by_name] function to obtain the default
+/// configuration for that architecture.
+pub const ALL_ARCHITECTURES: &[&str] = &["x86_64", "aarch64", "s390x", "riscv64"];
+
 /// Look for a supported ISA with the given `name`.
 /// Return a builder that can create a corresponding `TargetIsa`.
 pub fn lookup_by_name(name: &str) -> Result<Builder, LookupError> {

cranelift/fuzzgen/Cargo.toml

@@ -16,3 +16,4 @@ cranelift-native = { workspace = true }
 
 anyhow = { workspace = true }
 arbitrary = "1.0.0"
+target-lexicon = { workspace = true, features = ["std"] }

cranelift/fuzzgen/src/function_generator.rs

@@ -17,6 +17,7 @@ use cranelift::prelude::{
 };
 use std::collections::HashMap;
 use std::ops::RangeInclusive;
+use target_lexicon::{Architecture, Triple};
 
 /// Generates a Vec with `len` elements comprised of `options`
 fn arbitrary_vec<T: Clone>(
@@ -144,10 +145,15 @@ fn insert_cmp(
     let rhs = builder.use_var(rhs);
 
     let res = if opcode == Opcode::Fcmp {
+        let cc = *fgen.u.choose(FloatCC::all())?;
+
         // Some FloatCC's are not implemented on AArch64, see:
         // https://github.com/bytecodealliance/wasmtime/issues/4850
-        let float_cc = if cfg!(target_arch = "aarch64") {
-            &[
+        // We filter out condition codes that aren't supported by the target at
+        // this point after randomly choosing one, instead of randomly choosing a
+        // supported one, to avoid invalidating the corpus when these get implemented.
+        if matches!(fgen.target_triple.architecture, Architecture::Aarch64(_))
+            && ![
                 FloatCC::Ordered,
                 FloatCC::Unordered,
                 FloatCC::Equal,
@@ -157,11 +163,11 @@ fn insert_cmp(
                 FloatCC::GreaterThan,
                 FloatCC::GreaterThanOrEqual,
             ]
-        } else {
-            FloatCC::all()
+            .contains(&cc)
+        {
+            return Err(arbitrary::Error::IncorrectFormat.into());
         };
 
-        let cc = *fgen.u.choose(float_cc)?;
         builder.ins().fcmp(cc, lhs, rhs)
     } else {
         let cc = *fgen.u.choose(IntCC::all())?;
@@ -251,14 +257,222 @@ type OpcodeInserter = fn(
     &'static [Type],
 ) -> Result<()>;
 
-// TODO: Derive this from the `cranelift-meta` generator.
-#[rustfmt::skip]
-const OPCODE_SIGNATURES: &'static [(
+/// Returns true if we believe this `OpcodeSignature` should compile correctly
+/// for the given target triple. We currently have a range of known issues
+/// with specific lowerings on specific backends, and we don't want to get
+/// fuzz bug reports for those. Over time our goal is to eliminate all of these
+/// exceptions.
+fn valid_for_target(triple: &Triple, op: Opcode, args: &[Type], rets: &[Type]) -> bool {
+    macro_rules! exceptions {
+        ( $(($($cases:pat),*)),* $(,)?) => {
+            match (op, args, rets) {
+                $( ($($cases,)* ..) => false, )*
+                _ => true,
+            }
+        }
+    }
+
+    match triple.architecture {
+        Architecture::X86_64 => {
+            exceptions!(
+                (Opcode::IaddCout, &[I8, I8]),
+                (Opcode::IaddCout, &[I16, I16]),
+                (Opcode::IaddCout, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5468
+                (Opcode::Smulhi, &[I8, I8]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5468
+                (Opcode::Umulhi, &[I8, I8]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4756
+                (Opcode::Udiv, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4770
+                (Opcode::Sdiv, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5474
+                (Opcode::Urem, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5470
+                (Opcode::Srem, &[I8, I8]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5474
+                (Opcode::Srem, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5466
+                (Opcode::Iabs),
+                // https://github.com/bytecodealliance/wasmtime/issues/3370
+                (Opcode::Smin, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/3370
+                (Opcode::Umin, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/3370
+                (Opcode::Smax, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/3370
+                (Opcode::Umax, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Band, &[F32, F32]),
+                (Opcode::Band, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Bor, &[F32, F32]),
+                (Opcode::Bor, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Bxor, &[F32, F32]),
+                (Opcode::Bxor, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Bnot, &[F32, F32]),
+                (Opcode::Bnot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5041
+                (Opcode::BandNot, &[I8, I8]),
+                (Opcode::BandNot, &[I16, I16]),
+                (Opcode::BandNot, &[I32, I32]),
+                (Opcode::BandNot, &[I64, I64]),
+                (Opcode::BandNot, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::BandNot, &[F32, F32]),
+                (Opcode::BandNot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5041
+                (Opcode::BorNot, &[I8, I8]),
+                (Opcode::BorNot, &[I16, I16]),
+                (Opcode::BorNot, &[I32, I32]),
+                (Opcode::BorNot, &[I64, I64]),
+                (Opcode::BorNot, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::BorNot, &[F32, F32]),
+                (Opcode::BorNot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5041
+                (Opcode::BxorNot, &[I8, I8]),
+                (Opcode::BxorNot, &[I16, I16]),
+                (Opcode::BxorNot, &[I32, I32]),
+                (Opcode::BxorNot, &[I64, I64]),
+                (Opcode::BxorNot, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::BxorNot, &[F32, F32]),
+                (Opcode::BxorNot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5107
+                (Opcode::Cls, &[I8], &[I8]),
+                (Opcode::Cls, &[I16], &[I16]),
+                (Opcode::Cls, &[I32], &[I32]),
+                (Opcode::Cls, &[I64], &[I64]),
+                (Opcode::Cls, &[I128], &[I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5197
+                (Opcode::Bitselect, &[I8, I8, I8]),
+                (Opcode::Bitselect, &[I16, I16, I16]),
+                (Opcode::Bitselect, &[I32, I32, I32]),
+                (Opcode::Bitselect, &[I64, I64, I64]),
+                (Opcode::Bitselect, &[I128, I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4897
+                // https://github.com/bytecodealliance/wasmtime/issues/4899
+                (Opcode::FcvtToUint, &[F32], &[I8]),
+                (Opcode::FcvtToUint, &[F32], &[I16]),
+                (Opcode::FcvtToUint, &[F32], &[I128]),
+                (Opcode::FcvtToUint, &[F64], &[I8]),
+                (Opcode::FcvtToUint, &[F64], &[I16]),
+                (Opcode::FcvtToUint, &[F64], &[I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4897
+                // https://github.com/bytecodealliance/wasmtime/issues/4899
+                (Opcode::FcvtToUintSat, &[F32], &[I8]),
+                (Opcode::FcvtToUintSat, &[F32], &[I16]),
+                (Opcode::FcvtToUintSat, &[F32], &[I128]),
+                (Opcode::FcvtToUintSat, &[F64], &[I8]),
+                (Opcode::FcvtToUintSat, &[F64], &[I16]),
+                (Opcode::FcvtToUintSat, &[F64], &[I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4897
+                // https://github.com/bytecodealliance/wasmtime/issues/4899
+                (Opcode::FcvtToSint, &[F32], &[I8]),
+                (Opcode::FcvtToSint, &[F32], &[I16]),
+                (Opcode::FcvtToSint, &[F32], &[I128]),
+                (Opcode::FcvtToSint, &[F64], &[I8]),
+                (Opcode::FcvtToSint, &[F64], &[I16]),
+                (Opcode::FcvtToSint, &[F64], &[I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4897
+                // https://github.com/bytecodealliance/wasmtime/issues/4899
+                (Opcode::FcvtToSintSat, &[F32], &[I8]),
+                (Opcode::FcvtToSintSat, &[F32], &[I16]),
+                (Opcode::FcvtToSintSat, &[F32], &[I128]),
+                (Opcode::FcvtToSintSat, &[F64], &[I8]),
+                (Opcode::FcvtToSintSat, &[F64], &[I16]),
+                (Opcode::FcvtToSintSat, &[F64], &[I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4900
+                (Opcode::FcvtFromUint, &[I128], &[F32]),
+                (Opcode::FcvtFromUint, &[I128], &[F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4900
+                (Opcode::FcvtFromSint, &[I128], &[F32]),
+                (Opcode::FcvtFromSint, &[I128], &[F64]),
+            )
+        }
+
+        Architecture::Aarch64(_) => {
+            exceptions!(
+                (Opcode::IaddCout, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4864
+                (Opcode::Udiv, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4864
+                (Opcode::Sdiv, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5472
+                (Opcode::Urem, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5472
+                (Opcode::Srem, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5467
+                (Opcode::Iabs, &[I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4313
+                (Opcode::Smin, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4313
+                (Opcode::Umin, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4313
+                (Opcode::Smax, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4313
+                (Opcode::Umax, &[I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Band, &[F32, F32]),
+                (Opcode::Band, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Bor, &[F32, F32]),
+                (Opcode::Bor, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Bxor, &[F32, F32]),
+                (Opcode::Bxor, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::Bnot, &[F32, F32]),
+                (Opcode::Bnot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::BandNot, &[F32, F32]),
+                (Opcode::BandNot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::BorNot, &[F32, F32]),
+                (Opcode::BorNot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4870
+                (Opcode::BxorNot, &[F32, F32]),
+                (Opcode::BxorNot, &[F64, F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/5198
+                (Opcode::Bitselect, &[I128, I128, I128]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4934
+                (Opcode::FcvtToUint, &[F32]),
+                (Opcode::FcvtToUint, &[F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4934
+                (Opcode::FcvtToUintSat, &[F32]),
+                (Opcode::FcvtToUintSat, &[F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4934
+                (Opcode::FcvtToSint, &[F32]),
+                (Opcode::FcvtToSint, &[F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4934
+                (Opcode::FcvtToSintSat, &[F32]),
+                (Opcode::FcvtToSintSat, &[F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4933
+                (Opcode::FcvtFromUint, &[I128], &[F32]),
+                (Opcode::FcvtFromUint, &[I128], &[F64]),
+                // https://github.com/bytecodealliance/wasmtime/issues/4933
+                (Opcode::FcvtFromSint, &[I128], &[F32]),
+                (Opcode::FcvtFromSint, &[I128], &[F64]),
+            )
+        }
+
+        _ => true,
+    }
+}
+
+type OpcodeSignature = (
     Opcode,
     &'static [Type], // Args
     &'static [Type], // Rets
     OpcodeInserter,
-)] = &[
+);
+
+// TODO: Derive this from the `cranelift-meta` generator.
+#[rustfmt::skip]
+const OPCODE_SIGNATURES: &[OpcodeSignature] = &[
     (Opcode::Nop, &[], &[], insert_opcode),
     // Iadd
     (Opcode::Iadd, &[I8, I8], &[I8], insert_opcode),
@@ -267,14 +481,10 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Iadd, &[I64, I64], &[I64], insert_opcode),
     (Opcode::Iadd, &[I128, I128], &[I128], insert_opcode),
     // IaddCout
-    // IaddCout not implemented in x64
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::IaddCout, &[I8, I8], &[I8, I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::IaddCout, &[I16, I16], &[I16, I8], insert_opcode),
     (Opcode::IaddCout, &[I32, I32], &[I32, I8], insert_opcode),
     (Opcode::IaddCout, &[I64, I64], &[I64, I8], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::IaddCout, &[I128, I128], &[I128, I8], insert_opcode),
     // Isub
     (Opcode::Isub, &[I8, I8], &[I8], insert_opcode),
@@ -289,15 +499,11 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Imul, &[I64, I64], &[I64], insert_opcode),
     (Opcode::Imul, &[I128, I128], &[I128], insert_opcode),
     // Smulhi
-    // Not implemented on x64: https://github.com/bytecodealliance/wasmtime/issues/5468
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Smulhi, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Smulhi, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Smulhi, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Smulhi, &[I64, I64], &[I64], insert_opcode),
     // Umulhi
-    // Not implemented on x64: https://github.com/bytecodealliance/wasmtime/issues/5468
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Umulhi, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Umulhi, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Umulhi, &[I32, I32], &[I32], insert_opcode),
@@ -307,42 +513,24 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Udiv, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Udiv, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Udiv, &[I64, I64], &[I64], insert_opcode),
-    // udiv.i128 not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4756
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4864
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Udiv, &[I128, I128], &[I128], insert_opcode),
     // Sdiv
     (Opcode::Sdiv, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Sdiv, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Sdiv, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Sdiv, &[I64, I64], &[I64], insert_opcode),
-    // sdiv.i128 not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4770
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4864
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Sdiv, &[I128, I128], &[I128], insert_opcode),
     // Urem
     (Opcode::Urem, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Urem, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Urem, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Urem, &[I64, I64], &[I64], insert_opcode),
-    // urem.i128 not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/5474
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/5472
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Urem, &[I128, I128], &[I128], insert_opcode),
     // Srem
-    // Issues on x64: https://github.com/bytecodealliance/wasmtime/issues/5470
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Srem, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Srem, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Srem, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Srem, &[I64, I64], &[I64], insert_opcode),
-    // srem.i128 not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/5474
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/5472
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Srem, &[I128, I128], &[I128], insert_opcode),
     // Ineg
     (Opcode::Ineg, &[I8, I8], &[I8], insert_opcode),
@@ -351,58 +539,34 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Ineg, &[I64, I64], &[I64], insert_opcode),
     (Opcode::Ineg, &[I128, I128], &[I128], insert_opcode),
     // Iabs
-    // Some variants missing:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/5466
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/5467
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Iabs, &[I8], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Iabs, &[I16], &[I16], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Iabs, &[I32], &[I32], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Iabs, &[I64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Iabs, &[I128], &[I128], insert_opcode),
     // Smin
-    // smin.i128 is not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/3370
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4313
     (Opcode::Smin, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Smin, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Smin, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Smin, &[I64, I64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Smin, &[I128, I128], &[I128], insert_opcode),
     // Umin
-    // umin.i128 is not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/3370
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4313
     (Opcode::Umin, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Umin, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Umin, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Umin, &[I64, I64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Umin, &[I128, I128], &[I128], insert_opcode),
     // Smax
-    // smax.i128 is not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/3370
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4313
     (Opcode::Smax, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Smax, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Smax, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Smax, &[I64, I64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Smax, &[I128, I128], &[I128], insert_opcode),
     // Umax
-    // umax.i128 is not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/3370
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4313
     (Opcode::Umax, &[I8, I8], &[I8], insert_opcode),
     (Opcode::Umax, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Umax, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Umax, &[I64, I64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Umax, &[I128, I128], &[I128], insert_opcode),
     // Rotr
     (Opcode::Rotr, &[I8, I8], &[I8], insert_opcode),
@@ -577,11 +741,7 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Band, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Band, &[I64, I64], &[I64], insert_opcode),
     (Opcode::Band, &[I128, I128], &[I128], insert_opcode),
-    // Float bitops are currently not supported:
-    // See: https://github.com/bytecodealliance/wasmtime/issues/4870
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Band, &[F32, F32], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Band, &[F64, F64], &[F64], insert_opcode),
     // Bor
     (Opcode::Bor, &[I8, I8], &[I8], insert_opcode),
@@ -589,11 +749,7 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Bor, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Bor, &[I64, I64], &[I64], insert_opcode),
     (Opcode::Bor, &[I128, I128], &[I128], insert_opcode),
-    // Float bitops are currently not supported:
-    // See: https://github.com/bytecodealliance/wasmtime/issues/4870
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Bor, &[F32, F32], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Bor, &[F64, F64], &[F64], insert_opcode),
     // Bxor
     (Opcode::Bxor, &[I8, I8], &[I8], insert_opcode),
@@ -601,11 +757,7 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Bxor, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Bxor, &[I64, I64], &[I64], insert_opcode),
     (Opcode::Bxor, &[I128, I128], &[I128], insert_opcode),
-    // Float bitops are currently not supported:
-    // See: https://github.com/bytecodealliance/wasmtime/issues/4870
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Bxor, &[F32, F32], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Bxor, &[F64, F64], &[F64], insert_opcode),
     // Bnot
     (Opcode::Bnot, &[I8, I8], &[I8], insert_opcode),
@@ -613,65 +765,31 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Bnot, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Bnot, &[I64, I64], &[I64], insert_opcode),
     (Opcode::Bnot, &[I128, I128], &[I128], insert_opcode),
-    // Float bitops are currently not supported:
-    // See: https://github.com/bytecodealliance/wasmtime/issues/4870
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Bnot, &[F32, F32], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Bnot, &[F64, F64], &[F64], insert_opcode),
     // BandNot
-    // Some Integer ops not supported on x86: https://github.com/bytecodealliance/wasmtime/issues/5041
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BandNot, &[I8, I8], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BandNot, &[I16, I16], &[I16], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BandNot, &[I32, I32], &[I32], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BandNot, &[I64, I64], &[I64], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BandNot, &[I128, I128], &[I128], insert_opcode),
-    // Float bitops are currently not supported:
-    // See: https://github.com/bytecodealliance/wasmtime/issues/4870
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::BandNot, &[F32, F32], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::BandNot, &[F64, F64], &[F64], insert_opcode),
     // BorNot
-    // Some Integer ops not supported on x86: https://github.com/bytecodealliance/wasmtime/issues/5041
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BorNot, &[I8, I8], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BorNot, &[I16, I16], &[I16], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BorNot, &[I32, I32], &[I32], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BorNot, &[I64, I64], &[I64], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BorNot, &[I128, I128], &[I128], insert_opcode),
-    // Float bitops are currently not supported:
-    // See: https://github.com/bytecodealliance/wasmtime/issues/4870
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::BorNot, &[F32, F32], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::BorNot, &[F64, F64], &[F64], insert_opcode),
     // BxorNot
-    // Some Integer ops not supported on x86: https://github.com/bytecodealliance/wasmtime/issues/5041
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BxorNot, &[I8, I8], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BxorNot, &[I16, I16], &[I16], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BxorNot, &[I32, I32], &[I32], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BxorNot, &[I64, I64], &[I64], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::BxorNot, &[I128, I128], &[I128], insert_opcode),
-    // Float bitops are currently not supported:
-    // See: https://github.com/bytecodealliance/wasmtime/issues/4870
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::BxorNot, &[F32, F32], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::BxorNot, &[F64, F64], &[F64], insert_opcode),
     // Bitrev
     (Opcode::Bitrev, &[I8], &[I8], insert_opcode),
@@ -686,17 +804,10 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Clz, &[I64], &[I64], insert_opcode),
     (Opcode::Clz, &[I128], &[I128], insert_opcode),
     // Cls
-    // cls not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/5107
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Cls, &[I8], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Cls, &[I16], &[I16], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Cls, &[I32], &[I32], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Cls, &[I64], &[I64], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Cls, &[I128], &[I128], insert_opcode),
     // Ctz
     (Opcode::Ctz, &[I8], &[I8], insert_opcode),
@@ -742,18 +853,10 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Bswap, &[I64], &[I64], insert_opcode),
     (Opcode::Bswap, &[I128], &[I128], insert_opcode),
     // Bitselect
-    // TODO: Some ops disabled:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/5197
-    //   AArch64: https://github.com/bytecodealliance/wasmtime/issues/5198
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Bitselect, &[I8, I8, I8], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Bitselect, &[I16, I16, I16], &[I16], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Bitselect, &[I32, I32, I32], &[I32], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::Bitselect, &[I64, I64, I64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Bitselect, &[I128, I128, I128], &[I128], insert_opcode),
     // Select
     (Opcode::Select, &[I8, I8, I8], &[I8], insert_opcode),
@@ -863,120 +966,70 @@ const OPCODE_SIGNATURES: &'static [(
     // Fdemote
     (Opcode::Fdemote, &[F64], &[F32], insert_opcode),
     // FcvtToUint
-    // TODO: Some ops disabled:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4897
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4899
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4934
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUint, &[F32], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUint, &[F32], &[I16], insert_opcode),
     (Opcode::FcvtToUint, &[F32], &[I32], insert_opcode),
     (Opcode::FcvtToUint, &[F32], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToUint, &[F32], &[I128], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUint, &[F64], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUint, &[F64], &[I16], insert_opcode),
     (Opcode::FcvtToUint, &[F64], &[I32], insert_opcode),
     (Opcode::FcvtToUint, &[F64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToUint, &[F64], &[I128], insert_opcode),
     // FcvtToUintSat
-    // TODO: Some ops disabled:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4897
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4899
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4934
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUintSat, &[F32], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUintSat, &[F32], &[I16], insert_opcode),
     (Opcode::FcvtToUintSat, &[F32], &[I32], insert_opcode),
     (Opcode::FcvtToUintSat, &[F32], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToUintSat, &[F32], &[I128], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUintSat, &[F64], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToUintSat, &[F64], &[I16], insert_opcode),
     (Opcode::FcvtToUintSat, &[F64], &[I32], insert_opcode),
     (Opcode::FcvtToUintSat, &[F64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToUintSat, &[F64], &[I128], insert_opcode),
     // FcvtToSint
-    // TODO: Some ops disabled:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4897
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4899
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4934
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSint, &[F32], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSint, &[F32], &[I16], insert_opcode),
     (Opcode::FcvtToSint, &[F32], &[I32], insert_opcode),
     (Opcode::FcvtToSint, &[F32], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToSint, &[F32], &[I128], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSint, &[F64], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSint, &[F64], &[I16], insert_opcode),
     (Opcode::FcvtToSint, &[F64], &[I32], insert_opcode),
     (Opcode::FcvtToSint, &[F64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToSint, &[F64], &[I128], insert_opcode),
     // FcvtToSintSat
-    // TODO: Some ops disabled:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4897
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4899
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4934
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSintSat, &[F32], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSintSat, &[F32], &[I16], insert_opcode),
     (Opcode::FcvtToSintSat, &[F32], &[I32], insert_opcode),
     (Opcode::FcvtToSintSat, &[F32], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToSintSat, &[F32], &[I128], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSintSat, &[F64], &[I8], insert_opcode),
-    #[cfg(not(target_arch = "x86_64"))]
     (Opcode::FcvtToSintSat, &[F64], &[I16], insert_opcode),
     (Opcode::FcvtToSintSat, &[F64], &[I32], insert_opcode),
     (Opcode::FcvtToSintSat, &[F64], &[I64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtToSintSat, &[F64], &[I128], insert_opcode),
     // FcvtFromUint
-    // TODO: Some ops disabled:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4900
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4933
     (Opcode::FcvtFromUint, &[I8], &[F32], insert_opcode),
     (Opcode::FcvtFromUint, &[I16], &[F32], insert_opcode),
     (Opcode::FcvtFromUint, &[I32], &[F32], insert_opcode),
     (Opcode::FcvtFromUint, &[I64], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtFromUint, &[I128], &[F32], insert_opcode),
     (Opcode::FcvtFromUint, &[I8], &[F64], insert_opcode),
     (Opcode::FcvtFromUint, &[I16], &[F64], insert_opcode),
     (Opcode::FcvtFromUint, &[I32], &[F64], insert_opcode),
     (Opcode::FcvtFromUint, &[I64], &[F64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtFromUint, &[I128], &[F64], insert_opcode),
     // FcvtFromSint
-    // TODO: Some ops disabled:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/4900
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/4933
     (Opcode::FcvtFromSint, &[I8], &[F32], insert_opcode),
     (Opcode::FcvtFromSint, &[I16], &[F32], insert_opcode),
     (Opcode::FcvtFromSint, &[I32], &[F32], insert_opcode),
     (Opcode::FcvtFromSint, &[I64], &[F32], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtFromSint, &[I128], &[F32], insert_opcode),
     (Opcode::FcvtFromSint, &[I8], &[F64], insert_opcode),
     (Opcode::FcvtFromSint, &[I16], &[F64], insert_opcode),
     (Opcode::FcvtFromSint, &[I32], &[F64], insert_opcode),
     (Opcode::FcvtFromSint, &[I64], &[F64], insert_opcode),
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::FcvtFromSint, &[I128], &[F64], insert_opcode),
     // Fcmp
     (Opcode::Fcmp, &[F32, F32], &[I8], insert_cmp),
@@ -1075,6 +1128,7 @@ where
     u: &'r mut Unstructured<'data>,
     config: &'r Config,
     resources: Resources,
+    target_triple: Triple,
 }
 
 #[derive(Debug, Clone)]
@@ -1137,11 +1191,12 @@ impl<'r, 'data> FunctionGenerator<'r, 'data>
 where
     'data: 'r,
 {
-    pub fn new(u: &'r mut Unstructured<'data>, config: &'r Config) -> Self {
+    pub fn new(u: &'r mut Unstructured<'data>, config: &'r Config, target_triple: Triple) -> Self {
         Self {
             u,
             config,
             resources: Resources::default(),
+            target_triple,
         }
     }
 
@@ -1396,6 +1451,14 @@ where
     fn generate_instructions(&mut self, builder: &mut FunctionBuilder) -> Result<()> {
         for _ in 0..self.param(&self.config.instructions_per_block)? {
             let (op, args, rets, inserter) = *self.u.choose(OPCODE_SIGNATURES)?;
+
+            // We filter out instructions that aren't supported by the target at this point instead
+            // of building a single vector of valid instructions at the beginning of function
+            // generation, to avoid invalidating the corpus when instructions are enabled/disabled.
+            if !valid_for_target(&self.target_triple, op, args, rets) {
+                return Err(arbitrary::Error::IncorrectFormat.into());
+            }
+
             inserter(self, builder, op, args, rets)?;
         }
 

cranelift/fuzzgen/src/lib.rs

@@ -7,9 +7,11 @@ use cranelift::codegen::data_value::DataValue;
 use cranelift::codegen::ir::types::*;
 use cranelift::codegen::ir::Function;
 use cranelift::codegen::Context;
+use cranelift::prelude::isa;
 use cranelift::prelude::*;
 use cranelift_native::builder_with_options;
 use std::fmt;
+use target_lexicon::{Architecture, Triple};
 
 mod config;
 mod function_generator;
@@ -24,15 +26,77 @@ pub struct SingleFunction(pub Function);
 impl<'a> Arbitrary<'a> for SingleFunction {
     fn arbitrary(u: &mut Unstructured<'a>) -> arbitrary::Result<Self> {
         FuzzGen::new(u)
-            .generate_func()
+            .generate_func(Triple::host())
             .map_err(|_| arbitrary::Error::IncorrectFormat)
             .map(Self)
     }
 }
 
+/// Print only non default flags.
+fn write_non_default_flags(f: &mut fmt::Formatter<'_>, flags: &settings::Flags) -> fmt::Result {
+    let default_flags = settings::Flags::new(settings::builder());
+    for (default, flag) in default_flags.iter().zip(flags.iter()) {
+        assert_eq!(default.name, flag.name);
+
+        if default.value_string() != flag.value_string() {
+            writeln!(f, "set {}={}", flag.name, flag.value_string())?;
+        }
+    }
+
+    Ok(())
+}
+
+/// A generated function with an ISA that targets one of cranelift's backends.
+pub struct FunctionWithIsa {
+    /// TargetIsa to use when compiling this test case
+    pub isa: Box<dyn isa::TargetIsa>,
+
+    /// Function under test
+    pub func: Function,
+}
+
+impl fmt::Debug for FunctionWithIsa {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        writeln!(f, ";; Compile test case\n")?;
+
+        write_non_default_flags(f, self.isa.flags())?;
+
+        writeln!(f, "test compile")?;
+        writeln!(f, "target {}", self.isa.triple().architecture)?;
+        writeln!(f, "{}", self.func)?;
+
+        Ok(())
+    }
+}
+
+impl<'a> Arbitrary<'a> for FunctionWithIsa {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        // We filter out targets that aren't supported in the current build
+        // configuration after randomly choosing one, instead of randomly choosing
+        // a supported one, so that the same fuzz input works across different build
+        // configurations.
+        let target = u.choose(isa::ALL_ARCHITECTURES)?;
+        let builder = isa::lookup_by_name(target).map_err(|_| arbitrary::Error::IncorrectFormat)?;
+
+        let mut gen = FuzzGen::new(u);
+        let flags = gen
+            .generate_flags(builder.triple().architecture)
+            .map_err(|_| arbitrary::Error::IncorrectFormat)?;
+        let isa = builder
+            .finish(flags)
+            .map_err(|_| arbitrary::Error::IncorrectFormat)?;
+
+        let func = gen
+            .generate_func(isa.triple().clone())
+            .map_err(|_| arbitrary::Error::IncorrectFormat)?;
+
+        Ok(FunctionWithIsa { isa, func })
+    }
+}
+
 pub struct TestCase {
-    /// [Flags] to use when compiling this test case
-    pub flags: Flags,
+    /// TargetIsa to use when compiling this test case
+    pub isa: Box<dyn isa::TargetIsa>,
     /// Function under test
     pub func: Function,
     /// Generate multiple test inputs for each test case.
@@ -46,23 +110,10 @@ impl fmt::Debug for TestCase {
         writeln!(f, "test interpret")?;
         writeln!(f, "test run")?;
 
-        // Print only non default flags
-        let default_flags = Flags::new(settings::builder());
-        for (default, flag) in default_flags.iter().zip(self.flags.iter()) {
-            assert_eq!(default.name, flag.name);
-
-            if default.value_string() != flag.value_string() {
-                writeln!(f, "set {}={}", flag.name, flag.value_string())?;
-            }
-        }
-
-        writeln!(f, "target aarch64")?;
-        writeln!(f, "target s390x")?;
-        writeln!(f, "target riscv64")?;
-        writeln!(f, "target x86_64\n")?;
+        write_non_default_flags(f, self.isa.flags())?;
 
+        writeln!(f, "target {}", self.isa.triple().architecture)?;
         writeln!(f, "{}", self.func)?;
-
         writeln!(f, "; Note: the results in the below test cases are simply a placeholder and probably will be wrong\n")?;
 
         for input in self.inputs.iter() {
@@ -101,7 +152,7 @@ impl fmt::Debug for TestCase {
 impl<'a> Arbitrary<'a> for TestCase {
     fn arbitrary(u: &mut Unstructured<'a>) -> arbitrary::Result<Self> {
         FuzzGen::new(u)
-            .generate_test()
+            .generate_host_test()
             .map_err(|_| arbitrary::Error::IncorrectFormat)
     }
 }
@@ -224,14 +275,14 @@ where
         Ok(ctx.func)
     }
 
-    fn generate_func(&mut self) -> Result<Function> {
-        let func = FunctionGenerator::new(&mut self.u, &self.config).generate()?;
+    fn generate_func(&mut self, target_triple: Triple) -> Result<Function> {
+        let func = FunctionGenerator::new(&mut self.u, &self.config, target_triple).generate()?;
         self.run_func_passes(func)
     }
 
     /// Generate a random set of cranelift flags.
     /// Only semantics preserving flags are considered
-    fn generate_flags(&mut self) -> Result<Flags> {
+    fn generate_flags(&mut self, target_arch: Architecture) -> Result<Flags> {
         let mut builder = settings::builder();
 
         let opt = self.u.choose(OptLevel::all())?;
@@ -267,9 +318,15 @@ where
             builder.set(flag_name, value.as_str())?;
         }
 
+        let supports_inline_probestack = match target_arch {
+            Architecture::X86_64 => true,
+            Architecture::Aarch64(_) => true,
+            _ => false,
+        };
+
         // Optionally test inline stackprobes on supported platforms
         // TODO: Test outlined stack probes.
-        if supports_inline_probestack() && bool::arbitrary(self.u)? {
+        if supports_inline_probestack && bool::arbitrary(self.u)? {
             builder.enable("enable_probestack")?;
             builder.set("probestack_strategy", "inline")?;
 
@@ -283,7 +340,7 @@ where
 
         // We need llvm ABI extensions for i128 values on x86, so enable it regardless of
         // what we picked above.
-        if cfg!(target_arch = "x86_64") {
+        if target_arch == Architecture::X86_64 {
             builder.enable("enable_llvm_abi_extensions")?;
         }
 
@@ -300,26 +357,23 @@ where
         // into compilation anywhere, we leave it on unconditionally to make sure the generation doesn't panic.
         builder.enable("machine_code_cfg_info")?;
 
-        return Ok(Flags::new(builder));
-
-        fn supports_inline_probestack() -> bool {
-            cfg!(target_arch = "x86_64") || cfg!(target_arch = "aarch64")
-        }
+        Ok(Flags::new(builder))
     }
 
-    pub fn generate_test(mut self) -> Result<TestCase> {
+    pub fn generate_host_test(mut self) -> Result<TestCase> {
         // If we're generating test inputs as well as a function, then we're planning to execute
         // this function. That means that any function references in it need to exist. We don't yet
         // have infrastructure for generating multiple functions, so just don't generate funcrefs.
         self.config.funcrefs_per_function = 0..=0;
 
-        let flags = self.generate_flags()?;
-        let func = self.generate_func()?;
+        // TestCase is meant to be consumed by a runner, so we make the assumption here that we're
+        // generating a TargetIsa for the host.
+        let builder =
+            builder_with_options(true).expect("Unable to build a TargetIsa for the current host");
+        let flags = self.generate_flags(builder.triple().architecture)?;
+        let isa = builder.finish(flags)?;
+        let func = self.generate_func(isa.triple().clone())?;
         let inputs = self.generate_test_inputs(&func.signature)?;
-        Ok(TestCase {
-            flags,
-            func,
-            inputs,
-        })
+        Ok(TestCase { isa, func, inputs })
     }
 }

fuzz/Cargo.toml

@@ -10,7 +10,7 @@ cargo-fuzz = true
 [dependencies]
 anyhow = { workspace = true }
 once_cell = { workspace = true }
-cranelift-codegen = { workspace = true, features = ["incremental-cache"] }
+cranelift-codegen = { workspace = true, features = ["incremental-cache", "x86", "arm64"] }
 cranelift-reader = { workspace = true }
 cranelift-wasm = { workspace = true }
 cranelift-filetests = { workspace = true }

fuzz/fuzz_targets/cranelift-fuzzgen.rs

@@ -7,7 +7,7 @@ use std::sync::atomic::AtomicU64;
 use std::sync::atomic::Ordering;
 
 use cranelift_codegen::data_value::DataValue;
-use cranelift_codegen::ir::{LibCall, TrapCode};
+use cranelift_codegen::ir::{Function, LibCall, TrapCode};
 use cranelift_filetests::function_runner::{TestFileCompiler, Trampoline};
 use cranelift_fuzzgen::*;
 use cranelift_interpreter::environment::FuncIndex;
@@ -139,9 +139,9 @@ fn run_in_host(trampoline: &Trampoline, args: &[DataValue]) -> RunResult {
     RunResult::Success(res)
 }
 
-fn build_interpreter(testcase: &TestCase) -> Interpreter {
+fn build_interpreter(func: &Function) -> Interpreter {
     let mut env = FunctionStore::default();
-    env.add(testcase.func.name.to_string(), &testcase.func);
+    env.add(func.name.to_string(), &func);
 
     let state = InterpreterState::default()
         .with_function_store(env)
@@ -166,7 +166,7 @@ static STATISTICS: Lazy<Statistics> = Lazy::new(Statistics::default);
 
 fuzz_target!(|testcase: TestCase| {
     // This is the default, but we should ensure that it wasn't accidentally turned off anywhere.
-    assert!(testcase.flags.enable_verifier());
+    assert!(testcase.isa.flags().enable_verifier());
 
     // Periodically print statistics
     let valid_inputs = STATISTICS.valid_inputs.fetch_add(1, Ordering::SeqCst);
@@ -174,7 +174,7 @@ fuzz_target!(|testcase: TestCase| {
         STATISTICS.print(valid_inputs);
     }
 
-    let mut compiler = TestFileCompiler::with_host_isa(testcase.flags.clone()).unwrap();
+    let mut compiler = TestFileCompiler::new(testcase.isa);
     compiler.declare_function(&testcase.func).unwrap();
     compiler.define_function(testcase.func.clone()).unwrap();
     compiler
@@ -188,7 +188,7 @@ fuzz_target!(|testcase: TestCase| {
 
         // We rebuild the interpreter every run so that we don't accidentally carry over any state
         // between runs, such as fuel remaining.
-        let mut interpreter = build_interpreter(&testcase);
+        let mut interpreter = build_interpreter(&testcase.func);
         let int_res = run_in_interpreter(&mut interpreter, args);
         match int_res {
             RunResult::Success(_) => {

fuzz/fuzz_targets/cranelift-icache.rs

@@ -4,39 +4,14 @@ use cranelift_codegen::{
     cursor::{Cursor, FuncCursor},
     incremental_cache as icache,
     ir::{self, immediates::Imm64, ExternalName},
-    isa,
-    settings::{self, Configurable as _},
     Context,
 };
 use libfuzzer_sys::fuzz_target;
 
 use cranelift_fuzzgen::*;
-use target_lexicon::Triple;
 
-fuzz_target!(|func: SingleFunction| {
-    let mut func = func.0;
-
-    let flags = settings::Flags::new({
-        let mut builder = settings::builder();
-        // We need llvm ABI extensions for i128 values on x86
-        builder.set("enable_llvm_abi_extensions", "true").unwrap();
-
-        // This is the default, but we should ensure that it wasn't accidentally turned off anywhere.
-        builder.set("enable_verifier", "true").unwrap();
-
-        builder
-    });
-
-    let isa_builder = isa::lookup(Triple::host())
-        .map_err(|err| match err {
-            isa::LookupError::SupportDisabled => {
-                "support for architecture disabled at compile time"
-            }
-            isa::LookupError::Unsupported => "unsupported architecture",
-        })
-        .unwrap();
-
-    let isa = isa_builder.finish(flags).unwrap();
+fuzz_target!(|func: FunctionWithIsa| {
+    let FunctionWithIsa { mut func, isa } = func;
 
     let cache_key_hash = icache::compute_cache_key(&*isa, &mut func);