Cranelift: ensure ISA level needed for SIMD is present when SIMD is enabled. (#3816)

Addresses #3809: when we are asked to create a Cranelift backend with
shared flags that indicate support for SIMD, we should check that the
ISA level needed for our SIMD lowerings is present.

cranelift/codegen/meta/src/isa/x86.rs

@@ -17,19 +17,22 @@ fn define_settings(shared: &SettingGroup) -> SettingGroup {
         "has_sse3",
         "Has support for SSE3.",
         "SSE3: CPUID.01H:ECX.SSE3[bit 0]",
-        false,
+        // Needed for default `enable_simd` setting.
+        true,
     );
     let has_ssse3 = settings.add_bool(
         "has_ssse3",
         "Has support for SSSE3.",
         "SSSE3: CPUID.01H:ECX.SSSE3[bit 9]",
-        false,
+        // Needed for default `enable_simd` setting.
+        true,
     );
     let has_sse41 = settings.add_bool(
         "has_sse41",
         "Has support for SSE4.1.",
         "SSE4.1: CPUID.01H:ECX.SSE4_1[bit 19]",
-        false,
+        // Needed for default `enable_simd` setting.
+        true,
     );
     let has_sse42 = settings.add_bool(
         "has_sse42",

cranelift/codegen/src/isa/aarch64/inst/unwind/systemv.rs

@@ -85,7 +85,8 @@ mod tests {
     fn test_simple_func() {
         let isa = lookup(triple!("aarch64"))
             .expect("expect aarch64 ISA")
-            .finish(Flags::new(builder()));
+            .finish(Flags::new(builder()))
+            .expect("Creating compiler backend");
 
         let mut context = Context::for_function(create_function(
             CallConv::SystemV,
@@ -127,7 +128,8 @@ mod tests {
     fn test_multi_return_func() {
         let isa = lookup(triple!("aarch64"))
             .expect("expect aarch64 ISA")
-            .finish(Flags::new(builder()));
+            .finish(Flags::new(builder()))
+            .expect("Creating compiler backend");
 
         let mut context = Context::for_function(create_multi_return_function(CallConv::SystemV));
 

cranelift/codegen/src/isa/aarch64/mod.rs

@@ -172,7 +172,7 @@ pub fn isa_builder(triple: Triple) -> IsaBuilder {
         constructor: |triple, shared_flags, builder| {
             let isa_flags = aarch64_settings::Flags::new(&shared_flags, builder);
             let backend = AArch64Backend::new_with_flags(triple, shared_flags, isa_flags);
-            Box::new(backend)
+            Ok(Box::new(backend))
         },
     }
 }

cranelift/codegen/src/isa/mod.rs

@@ -139,7 +139,8 @@ impl fmt::Display for LookupError {
 pub struct Builder {
     triple: Triple,
     setup: settings::Builder,
-    constructor: fn(Triple, settings::Flags, settings::Builder) -> Box<dyn TargetIsa>,
+    constructor:
+        fn(Triple, settings::Flags, settings::Builder) -> CodegenResult<Box<dyn TargetIsa>>,
 }
 
 impl Builder {
@@ -153,9 +154,13 @@ impl Builder {
         self.setup.iter()
     }
 
-    /// Combine the ISA-specific settings with the provided ISA-independent settings and allocate a
-    /// fully configured `TargetIsa` trait object.
-    pub fn finish(self, shared_flags: settings::Flags) -> Box<dyn TargetIsa> {
+    /// Combine the ISA-specific settings with the provided
+    /// ISA-independent settings and allocate a fully configured
+    /// `TargetIsa` trait object. May return an error if some of the
+    /// flags are inconsistent or incompatible: for example, some
+    /// platform-independent features, like general SIMD support, may
+    /// need certain ISA extensions to be enabled.
+    pub fn finish(self, shared_flags: settings::Flags) -> CodegenResult<Box<dyn TargetIsa>> {
         (self.constructor)(self.triple, shared_flags, self.setup)
     }
 }

cranelift/codegen/src/isa/s390x/inst/unwind/systemv.rs

@@ -100,7 +100,8 @@ mod tests {
     fn test_simple_func() {
         let isa = lookup(triple!("s390x"))
             .expect("expect s390x ISA")
-            .finish(Flags::new(builder()));
+            .finish(Flags::new(builder()))
+            .expect("Creating compiler backend");
 
         let mut context = Context::for_function(create_function(
             CallConv::SystemV,
@@ -142,7 +143,8 @@ mod tests {
     fn test_multi_return_func() {
         let isa = lookup(triple!("s390x"))
             .expect("expect s390x ISA")
-            .finish(Flags::new(builder()));
+            .finish(Flags::new(builder()))
+            .expect("Creating compiler backend");
 
         let mut context = Context::for_function(create_multi_return_function(
             CallConv::SystemV,

cranelift/codegen/src/isa/s390x/mod.rs

@@ -179,7 +179,7 @@ pub fn isa_builder(triple: Triple) -> IsaBuilder {
         constructor: |triple, shared_flags, builder| {
             let isa_flags = s390x_settings::Flags::new(&shared_flags, builder);
             let backend = S390xBackend::new_with_flags(triple, shared_flags, isa_flags);
-            Box::new(backend)
+            Ok(Box::new(backend))
         },
     }
 }

cranelift/codegen/src/isa/x64/inst/unwind/systemv.rs

@@ -112,7 +112,8 @@ mod tests {
     fn test_simple_func() {
         let isa = lookup(triple!("x86_64"))
             .expect("expect x86 ISA")
-            .finish(Flags::new(builder()));
+            .finish(Flags::new(builder()))
+            .expect("expect backend creation to succeed");
 
         let mut context = Context::for_function(create_function(
             CallConv::SystemV,
@@ -154,7 +155,8 @@ mod tests {
     fn test_multi_return_func() {
         let isa = lookup(triple!("x86_64"))
             .expect("expect x86 ISA")
-            .finish(Flags::new(builder()));
+            .finish(Flags::new(builder()))
+            .expect("expect backend creation to succeed");
 
         let mut context = Context::for_function(create_multi_return_function(CallConv::SystemV));
 

cranelift/codegen/src/isa/x64/mod.rs

@@ -11,7 +11,7 @@ use crate::isa::Builder as IsaBuilder;
 use crate::machinst::{
     compile, MachCompileResult, MachTextSectionBuilder, TextSectionBuilder, VCode,
 };
-use crate::result::CodegenResult;
+use crate::result::{CodegenError, CodegenResult};
 use crate::settings::{self as shared_settings, Flags};
 use alloc::{boxed::Box, vec::Vec};
 use core::fmt;
@@ -174,10 +174,21 @@ fn isa_constructor(
     triple: Triple,
     shared_flags: Flags,
     builder: shared_settings::Builder,
-) -> Box<dyn TargetIsa> {
+) -> CodegenResult<Box<dyn TargetIsa>> {
     let isa_flags = x64_settings::Flags::new(&shared_flags, builder);
+
+    // Check for compatibility between flags and ISA level
+    // requested. In particular, SIMD support requires SSE4.1.
+    if shared_flags.enable_simd() {
+        if !isa_flags.has_sse3() || !isa_flags.has_ssse3() || !isa_flags.has_sse41() {
+            return Err(CodegenError::Unsupported(
+                "SIMD support requires SSE3, SSSE3, and SSE4.1 on x86_64.".into(),
+            ));
+        }
+    }
+
     let backend = X64Backend::new_with_flags(triple, shared_flags, isa_flags);
-    Box::new(backend)
+    Ok(Box::new(backend))
 }
 
 #[cfg(test)]
@@ -332,4 +343,20 @@ mod test {
 
         assert_eq!(code, &golden[..]);
     }
+
+    // Check that feature tests for SIMD work correctly.
+    #[test]
+    fn simd_required_features() {
+        let mut shared_flags_builder = settings::builder();
+        shared_flags_builder.set("enable_simd", "true").unwrap();
+        let shared_flags = settings::Flags::new(shared_flags_builder);
+        let mut isa_builder = crate::isa::lookup_by_name("x86_64").unwrap();
+        isa_builder.set("has_sse3", "false").unwrap();
+        isa_builder.set("has_ssse3", "false").unwrap();
+        isa_builder.set("has_sse41", "false").unwrap();
+        assert!(matches!(
+            isa_builder.finish(shared_flags),
+            Err(CodegenError::Unsupported(_)),
+        ));
+    }
 }

cranelift/filetests/filetests/isa/x64/simd-lane-access-compile.clif

@@ -1,6 +1,6 @@
 test compile precise-output
 set enable_simd
-target x86_64 has_ssse3 has_sse41
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 ;; shuffle
 

cranelift/filetests/filetests/runtests/simd-bitselect.clif

@@ -1,7 +1,7 @@
 test run
 set enable_simd
 target aarch64
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %bitselect_i32x4(i32x4, i32x4, i32x4) -> i32x4 {
 block0(v0: i32x4, v1: i32x4, v2: i32x4):

cranelift/filetests/filetests/runtests/simd-comparison.clif

@@ -2,7 +2,7 @@ test run
 target aarch64
 ; target s390x TODO: Not yet implemented on s390x
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %icmp_eq_i8x16() -> b8 {
 block0:

cranelift/filetests/filetests/runtests/simd-conversion.clif

@@ -2,7 +2,7 @@ test run
 target aarch64
 ; target s390x TODO: Not yet implemented on s390x
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %fcvt_from_sint(i32x4) -> f32x4 {
 block0(v0: i32x4):

cranelift/filetests/filetests/runtests/simd-extractlane.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %extractlane_4(i8x16) -> i8 {
 block0(v0: i8x16):

cranelift/filetests/filetests/runtests/simd-iabs.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %iabs_i8x16(i8x16) -> i8x16 {
 block0(v0: i8x16):

cranelift/filetests/filetests/runtests/simd-insertlane.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %insertlane_15(i8x16, i8) -> i8x16 {
 block0(v0: i8x16, v1: i8):

cranelift/filetests/filetests/runtests/simd-lane-access.clif

@@ -2,7 +2,7 @@ test run
 target aarch64
 ; target s390x TODO: Not yet implemented on s390x
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 ;; shuffle
 

cranelift/filetests/filetests/runtests/simd-logical.clif

@@ -2,7 +2,7 @@ test run
 target aarch64
 ; target s390x TODO: Not yet implemented on s390x
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %bnot() -> b32 {
 block0:

cranelift/filetests/filetests/runtests/simd-saddsat.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %saddsat_i8x16(i8x16, i8x16) -> i8x16 {
 block0(v0: i8x16, v1: i8x16):

cranelift/filetests/filetests/runtests/simd-shuffle.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %shuffle_i8x16(i8x16, i8x16) -> i8x16 {
 block0(v0: i8x16, v1: i8x16):

cranelift/filetests/filetests/runtests/simd-snarrow.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %snarrow_i16x8(i16x8, i16x8) -> i8x16 {
 block0(v0: i16x8, v1: i16x8):

cranelift/filetests/filetests/runtests/simd-splat.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %splat_i8x16(i8) -> i8x16 {
 block0(v0: i8):

cranelift/filetests/filetests/runtests/simd-sqmulroundsat.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %sqmulrs_i16x8(i16x8, i16x8) -> i16x8 {
 block0(v0: i16x8, v1: i16x8):

cranelift/filetests/filetests/runtests/simd-ssubsat.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %ssubsat_i8x16(i8x16, i8x16) -> i8x16 {
 block0(v0: i8x16, v1: i8x16):

cranelift/filetests/filetests/runtests/simd-swidenhigh.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %swidenhigh_i8x16(i8x16) -> i16x8 {
 block0(v0: i8x16):

cranelift/filetests/filetests/runtests/simd-swidenlow.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %swidenlow_i8x16(i8x16) -> i16x8 {
 block0(v0: i8x16):

cranelift/filetests/filetests/runtests/simd-swizzle.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %swizzle_i8x16(i8x16, i8x16) -> i8x16 {
 block0(v0: i8x16, v1: i8x16):

cranelift/filetests/filetests/runtests/simd-uaddsat.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %uaddsat_i8x16(i8x16, i8x16) -> i8x16 {
 block0(v0: i8x16, v1: i8x16):

cranelift/filetests/filetests/runtests/simd-unarrow.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %unarrow_i16x8(i16x8, i16x8) -> i8x16 {
 block0(v0: i16x8, v1: i16x8):

cranelift/filetests/filetests/runtests/simd-usubsat.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %usubsat_i8x16(i8x16, i8x16) -> i8x16 {
 block0(v0: i8x16, v1: i8x16):

cranelift/filetests/filetests/runtests/simd-uwidenhigh.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %uwidenhigh_i8x16(i8x16) -> i16x8 {
 block0(v0: i8x16):

cranelift/filetests/filetests/runtests/simd-uwidenlow.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %uwidenlow_i8x16(i8x16) -> i16x8 {
 block0(v0: i8x16):

cranelift/filetests/filetests/runtests/simd-vconst.clif

@@ -2,7 +2,7 @@ test run
 ; target s390x TODO: Not yet implemented on s390x
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 
 function %vconst_zeroes() -> b1 {

cranelift/filetests/filetests/runtests/simd-vhighbits.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %vhighbits_i8x16(i8x16) -> i16 {
 block0(v0: i8x16):

cranelift/filetests/filetests/runtests/simd-vselect.clif

@@ -3,7 +3,7 @@ test run
 ; target s390x TODO: Not yet implemented on s390x
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %vselect_i8x16() -> i8x16 {
 block0:

cranelift/filetests/filetests/runtests/simd-wideningpairwisedotproducts.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %wpdps(i16x8, i16x8) -> i32x4 {
 block0(v0: i16x8, v1: i16x8):

cranelift/filetests/filetests/runtests/smulhi.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %smulhi_i16(i16, i16) -> i16 {
 block0(v0: i16, v1: i16):

cranelift/filetests/filetests/runtests/umulhi.clif

@@ -2,7 +2,7 @@ test interpret
 test run
 target aarch64
 set enable_simd
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 target s390x
 
 function %umulhi_i16(i16, i16) -> i16 {

cranelift/filetests/filetests/verifier/scalar-to-vector.clif

@@ -1,7 +1,7 @@
 test verifier
 set enable_simd=true
 target aarch64
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %scalar_to_vector() {
 block0:

cranelift/filetests/filetests/verifier/simd-lane-index.clif

@@ -1,7 +1,7 @@
 test verifier
 set enable_simd
 target aarch64
-target x86_64
+target x86_64 has_sse3 has_ssse3 has_sse41
 
 function %insertlane_i32x4() {
 block0:

cranelift/filetests/src/function_runner.rs

@@ -1,4 +1,5 @@
 //! Provides functionality for compiling and running CLIF IR for `run` tests.
+use anyhow::Result;
 use core::mem;
 use cranelift_codegen::data_value::DataValue;
 use cranelift_codegen::ir::{condcodes::IntCC, Function, InstBuilder, Signature};
@@ -27,7 +28,7 @@ use thiserror::Error;
 ///
 /// let code = "test run \n function %add(i32, i32) -> i32 {  block0(v0:i32, v1:i32):  v2 = iadd v0, v1  return v2 }".into();
 /// let func = parse_functions(code).unwrap().into_iter().nth(0).unwrap();
-/// let mut compiler = SingleFunctionCompiler::with_default_host_isa();
+/// let mut compiler = SingleFunctionCompiler::with_default_host_isa().unwrap();
 /// let compiled_func = compiler.compile(func).unwrap();
 /// println!("Address of compiled function: {:p}", compiled_func.as_ptr());
 /// ```
@@ -46,16 +47,16 @@ impl SingleFunctionCompiler {
     }
 
     /// Build a [SingleFunctionCompiler] using the host machine's ISA and the passed flags.
-    pub fn with_host_isa(flags: settings::Flags) -> Self {
+    pub fn with_host_isa(flags: settings::Flags) -> Result<Self> {
         let builder =
             builder_with_options(true).expect("Unable to build a TargetIsa for the current host");
-        let isa = builder.finish(flags);
-        Self::new(isa)
+        let isa = builder.finish(flags)?;
+        Ok(Self::new(isa))
     }
 
     /// Build a [SingleFunctionCompiler] using the host machine's ISA and the default flags for this
     /// ISA.
-    pub fn with_default_host_isa() -> Self {
+    pub fn with_default_host_isa() -> Result<Self> {
         let flags = settings::Flags::new(settings::builder());
         Self::with_host_isa(flags)
     }
@@ -135,7 +136,7 @@ impl Trampoline {
 ///
 /// let code = "test run \n function %add(i32, i32) -> i32 {  block0(v0:i32, v1:i32):  v2 = iadd v0, v1  return v2 }".into();
 /// let func = parse_functions(code).unwrap().into_iter().nth(0).unwrap();
-/// let mut compiler = SingleFunctionCompiler::with_default_host_isa();
+/// let mut compiler = SingleFunctionCompiler::with_default_host_isa().unwrap();
 /// let compiled_func = compiler.compile(func).unwrap();
 ///
 /// let returned = compiled_func.call(&vec![DataValue::I32(2), DataValue::I32(40)]);
@@ -377,7 +378,7 @@ mod test {
         let function = test_file.functions[0].0.clone();
 
         // execute function
-        let mut compiler = SingleFunctionCompiler::with_default_host_isa();
+        let mut compiler = SingleFunctionCompiler::with_default_host_isa().unwrap();
         let compiled_function = compiler.compile(function).unwrap();
         let returned = compiled_function.call(&[]);
         assert_eq!(returned, vec![DataValue::B(true)])
@@ -395,7 +396,7 @@ mod test {
             }",
         );
 
-        let compiler = SingleFunctionCompiler::with_default_host_isa();
+        let compiler = SingleFunctionCompiler::with_default_host_isa().unwrap();
         let trampoline = make_trampoline(&function.signature, compiler.isa.as_ref());
         assert!(format!("{}", trampoline).ends_with(
             "sig0 = (f32, i8, i64x2, b1) -> f32x4, b64 fast

cranelift/filetests/src/test_run.rs

@@ -51,7 +51,7 @@ impl SubTest for TestRun {
 
         let test_env = RuntestEnvironment::parse(&context.details.comments[..])?;
 
-        let mut compiler = SingleFunctionCompiler::with_host_isa(context.flags.clone());
+        let mut compiler = SingleFunctionCompiler::with_host_isa(context.flags.clone())?;
         for comment in context.details.comments.iter() {
             if let Some(command) = parse_run_command(comment.text, &func.signature)? {
                 trace!("Parsed run command: {}", command);

cranelift/frontend/src/frontend.rs

@@ -1355,7 +1355,8 @@ block0:
         let target = isa::lookup(triple)
             .ok()
             .map(|b| b.finish(shared_flags))
-            .expect("This test requires x86_64 support.");
+            .expect("This test requires x86_64 support.")
+            .expect("Should be able to create backend with default flags");
 
         let mut sig = Signature::new(target.default_call_conv());
         sig.returns.push(AbiParam::new(I32));
@@ -1567,7 +1568,8 @@ block0:
         let target = isa::lookup(triple)
             .ok()
             .map(|b| b.finish(shared_flags))
-            .expect("This test requires x86_64 support.");
+            .expect("This test requires x86_64 support.")
+            .expect("Should be able to create backend with default flags");
 
         let mut sig = Signature::new(target.default_call_conv());
         sig.returns.push(AbiParam::new(B1));

cranelift/jit/examples/jit-minimal.rs

@@ -12,7 +12,9 @@ fn main() {
     let isa_builder = cranelift_native::builder().unwrap_or_else(|msg| {
         panic!("host machine is not supported: {}", msg);
     });
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module = JITModule::new(JITBuilder::with_isa(isa, default_libcall_names()));
 
     let mut ctx = module.make_context();

cranelift/jit/src/backend.rs

@@ -42,7 +42,9 @@ impl JITBuilder {
     /// enum to symbols. LibCalls are inserted in the IR as part of the legalization for certain
     /// floating point instructions, and for stack probes. If you don't know what to use for this
     /// argument, use `cranelift_module::default_libcall_names()`.
-    pub fn new(libcall_names: Box<dyn Fn(ir::LibCall) -> String + Send + Sync>) -> Self {
+    pub fn new(
+        libcall_names: Box<dyn Fn(ir::LibCall) -> String + Send + Sync>,
+    ) -> ModuleResult<Self> {
         let mut flag_builder = settings::builder();
         // On at least AArch64, "colocated" calls use shorter-range relocations,
         // which might not reach all definitions; we can't handle that here, so
@@ -52,8 +54,8 @@ impl JITBuilder {
         let isa_builder = cranelift_native::builder().unwrap_or_else(|msg| {
             panic!("host machine is not supported: {}", msg);
         });
-        let isa = isa_builder.finish(settings::Flags::new(flag_builder));
-        Self::with_isa(isa, libcall_names)
+        let isa = isa_builder.finish(settings::Flags::new(flag_builder))?;
+        Ok(Self::with_isa(isa, libcall_names))
     }
 
     /// Create a new `JITBuilder` with an arbitrary target. This is mainly

cranelift/jit/tests/basic.rs

@@ -16,7 +16,9 @@ fn error_on_incompatible_sig_in_declare_function() {
     let isa_builder = cranelift_native::builder().unwrap_or_else(|msg| {
         panic!("host machine is not supported: {}", msg);
     });
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module = JITModule::new(JITBuilder::with_isa(isa, default_libcall_names()));
 
     let mut sig = Signature {
@@ -70,7 +72,9 @@ fn panic_on_define_after_finalize() {
     let isa_builder = cranelift_native::builder().unwrap_or_else(|msg| {
         panic!("host machine is not supported: {}", msg);
     });
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module = JITModule::new(JITBuilder::with_isa(isa, default_libcall_names()));
 
     define_simple_function(&mut module);
@@ -159,7 +163,9 @@ fn libcall_function() {
     let isa_builder = cranelift_native::builder().unwrap_or_else(|msg| {
         panic!("host machine is not supported: {}", msg);
     });
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module = JITModule::new(JITBuilder::with_isa(isa, default_libcall_names()));
 
     let sig = Signature {

cranelift/native/src/lib.rs

@@ -156,7 +156,9 @@ mod tests {
     fn test() {
         if let Ok(isa_builder) = builder() {
             let flag_builder = settings::builder();
-            let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+            let isa = isa_builder
+                .finish(settings::Flags::new(flag_builder))
+                .unwrap();
 
             if cfg!(all(target_os = "macos", target_arch = "aarch64")) {
                 assert_eq!(isa.default_call_conv(), CallConv::AppleAarch64);

cranelift/object/tests/basic.rs

@@ -11,7 +11,9 @@ use cranelift_object::*;
 fn error_on_incompatible_sig_in_declare_function() {
     let flag_builder = settings::builder();
     let isa_builder = cranelift_codegen::isa::lookup_by_name("x86_64-unknown-linux-gnu").unwrap();
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module =
         ObjectModule::new(ObjectBuilder::new(isa, "foo", default_libcall_names()).unwrap());
     let mut sig = Signature {
@@ -60,7 +62,9 @@ fn define_simple_function(module: &mut ObjectModule) -> FuncId {
 fn panic_on_define_after_finalize() {
     let flag_builder = settings::builder();
     let isa_builder = cranelift_codegen::isa::lookup_by_name("x86_64-unknown-linux-gnu").unwrap();
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module =
         ObjectModule::new(ObjectBuilder::new(isa, "foo", default_libcall_names()).unwrap());
 
@@ -145,7 +149,9 @@ fn switch_error() {
 fn libcall_function() {
     let flag_builder = settings::builder();
     let isa_builder = cranelift_codegen::isa::lookup_by_name("x86_64-unknown-linux-gnu").unwrap();
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module =
         ObjectModule::new(ObjectBuilder::new(isa, "foo", default_libcall_names()).unwrap());
 
@@ -199,7 +205,9 @@ fn libcall_function() {
 fn reject_nul_byte_symbol_for_func() {
     let flag_builder = settings::builder();
     let isa_builder = cranelift_codegen::isa::lookup_by_name("x86_64-unknown-linux-gnu").unwrap();
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module =
         ObjectModule::new(ObjectBuilder::new(isa, "foo", default_libcall_names()).unwrap());
 
@@ -221,7 +229,9 @@ fn reject_nul_byte_symbol_for_func() {
 fn reject_nul_byte_symbol_for_data() {
     let flag_builder = settings::builder();
     let isa_builder = cranelift_codegen::isa::lookup_by_name("x86_64-unknown-linux-gnu").unwrap();
-    let isa = isa_builder.finish(settings::Flags::new(flag_builder));
+    let isa = isa_builder
+        .finish(settings::Flags::new(flag_builder))
+        .unwrap();
     let mut module =
         ObjectModule::new(ObjectBuilder::new(isa, "foo", default_libcall_names()).unwrap());
 

cranelift/reader/src/parser.rs

@@ -1053,7 +1053,15 @@ impl<'a> Parser<'a> {
             specified_target = true;
 
             // Construct a trait object with the aggregate settings.
-            targets.push(isa_builder.finish(settings::Flags::new(flag_builder.clone())));
+            targets.push(
+                isa_builder
+                    .finish(settings::Flags::new(flag_builder.clone()))
+                    .map_err(|e| ParseError {
+                        location: loc,
+                        message: format!("invalid ISA flags for '{}': {:?}", targ, e),
+                        is_warning: false,
+                    })?,
+            );
         }
 
         if !specified_target {
@@ -1122,7 +1130,18 @@ impl<'a> Parser<'a> {
                     isaspec::parse_options(words, &mut isa_builder, self.loc)?;
 
                     // Construct a trait object with the aggregate settings.
-                    targets.push(isa_builder.finish(settings::Flags::new(flag_builder.clone())));
+                    targets.push(
+                        isa_builder
+                            .finish(settings::Flags::new(flag_builder.clone()))
+                            .map_err(|e| ParseError {
+                                location: loc,
+                                message: format!(
+                                    "invalid ISA flags for '{}': {:?}",
+                                    target_name, e
+                                ),
+                                is_warning: false,
+                            })?,
+                    );
                 }
                 _ => break,
             }

cranelift/src/run.rs

@@ -110,7 +110,7 @@ fn create_target_isa(isa_spec: &IsaSpec) -> Result<Box<dyn TargetIsa>> {
     if let IsaSpec::None(flags) = isa_spec {
         // build an ISA for the current machine
         let builder = host_isa_builder().map_err(|s| anyhow::anyhow!("{}", s))?;
-        Ok(builder.finish(flags.clone()))
+        Ok(builder.finish(flags.clone())?)
     } else {
         anyhow::bail!(
             "A target ISA was specified in the file but should not have been--only \

cranelift/src/utils.rs

@@ -99,7 +99,7 @@ pub fn parse_sets_and_triple(
             .map_err(ParseError::from)?;
 
         Ok(OwnedFlagsOrIsa::Isa(
-            isa_builder.finish(settings::Flags::new(flag_builder)),
+            isa_builder.finish(settings::Flags::new(flag_builder))?,
         ))
     } else {
         if !unknown_settings.is_empty() {

crates/cranelift/src/builder.rs

@@ -101,12 +101,15 @@ impl CompilerBuilder for Builder {
         Ok(())
     }
 
-    fn build(&self) -> Box<dyn wasmtime_environ::Compiler> {
+    fn build(&self) -> Result<Box<dyn wasmtime_environ::Compiler>> {
         let isa = self
             .isa_flags
             .clone()
-            .finish(settings::Flags::new(self.flags.clone()));
-        Box::new(crate::compiler::Compiler::new(isa, self.linkopts.clone()))
+            .finish(settings::Flags::new(self.flags.clone()))?;
+        Ok(Box::new(crate::compiler::Compiler::new(
+            isa,
+            self.linkopts.clone(),
+        )))
     }
 
     fn settings(&self) -> Vec<Setting> {

crates/environ/src/compilation.rs

@@ -104,7 +104,7 @@ pub trait CompilerBuilder: Send + Sync + fmt::Debug {
     fn settings(&self) -> Vec<Setting>;
 
     /// Builds a new [`Compiler`] object from this configuration.
-    fn build(&self) -> Box<dyn Compiler>;
+    fn build(&self) -> Result<Box<dyn Compiler>>;
 }
 
 /// Description of compiler settings returned by [`CompilerBuilder::settings`].

crates/wasmtime/src/engine.rs

@@ -64,7 +64,7 @@ impl Engine {
         Ok(Engine {
             inner: Arc::new(EngineInner {
                 #[cfg(compiler)]
-                compiler: config.compiler.build(),
+                compiler: config.compiler.build()?,
                 config,
                 allocator,
                 signatures: registry,

fuzz/fuzz_targets/cranelift-fuzzgen.rs

@@ -60,7 +60,7 @@ fuzz_target!(|testcase: TestCase| {
     };
 
     // Native fn
-    let mut host_compiler = SingleFunctionCompiler::with_default_host_isa();
+    let mut host_compiler = SingleFunctionCompiler::with_default_host_isa().unwrap();
     let compiled_fn = host_compiler.compile(testcase.func.clone()).unwrap();
 
     for args in &testcase.inputs {

src/commands/settings.rs

@@ -62,7 +62,7 @@ impl SettingsCommand {
         }
 
         if self.target.is_none() {
-            let compiler = builder.build();
+            let compiler = builder.build()?;
             println!();
             println!("Settings inferred for the current host:");