Make use of Lightbeam configurable.

This adds a `--always-lightbeam` option as well as an `--always-cranelift`
option, to allow the compilation strategy to be selected via the
command-line. This also enables regular testing for Lightbeam.

build.rs

@@ -14,12 +14,24 @@ fn main() {
     let mut out = File::create(out_dir.join("wast_testsuite_tests.rs"))
         .expect("error generating test source file");
 
-    test_directory(&mut out, "misc_testsuite").expect("generating tests");
+    for strategy in &["AlwaysCranelift", "AlwaysLightbeam"] {
-    test_directory(&mut out, "spec_testsuite").expect("generating tests");
+        writeln!(out, "#[allow(non_snake_case)]").expect("generating tests");
-    test_file(&mut out, "spec_testsuite/proposals/simd/simd_const.wast").expect("generating tests");
+        writeln!(out, "mod {} {{", strategy).expect("generating tests");
+
+        test_directory(&mut out, "misc_testsuite", strategy).expect("generating tests");
+        test_directory(&mut out, "spec_testsuite", strategy).expect("generating tests");
+        test_file(
+            &mut out,
+            "spec_testsuite/proposals/simd/simd_const.wast",
+            strategy,
+        )
+        .expect("generating tests");
+
+        writeln!(out, "}}").expect("generating tests");
+    }
 }
 
-fn test_directory(out: &mut File, testsuite: &str) -> io::Result<()> {
+fn test_directory(out: &mut File, testsuite: &str, strategy: &str) -> io::Result<()> {
     let mut dir_entries: Vec<_> = read_dir(testsuite)
         .expect("reading testsuite directory")
         .map(|r| r.expect("reading testsuite directory entry"))
@@ -44,6 +56,22 @@ fn test_directory(out: &mut File, testsuite: &str) -> io::Result<()> {
 
     dir_entries.sort_by_key(|dir| dir.path());
 
+    start_test_module(out, testsuite)?;
+    for dir_entry in dir_entries {
+        write_testsuite_tests(out, &dir_entry.path(), testsuite, strategy)?;
+    }
+    finish_test_module(out)
+}
+
+fn test_file(out: &mut File, testfile: &str, strategy: &str) -> io::Result<()> {
+    let testsuite = "single_file_spec_test";
+    let path = Path::new(testfile);
+    start_test_module(out, testsuite)?;
+    write_testsuite_tests(out, path, testsuite, strategy)?;
+    finish_test_module(out)
+}
+
+fn start_test_module(out: &mut File, testsuite: &str) -> io::Result<()> {
     writeln!(
         out,
         "    mod {} {{",
@@ -52,25 +80,24 @@ fn test_directory(out: &mut File, testsuite: &str) -> io::Result<()> {
             .expect("testsuite filename should have a stem")
             .to_str()
             .expect("testsuite filename should be representable as a string")
-            .replace("-", "_")
+            .replace("-", "_"),
     )?;
     writeln!(
         out,
-        "    use super::{{native_isa, Path, WastContext, Compiler, Features}};"
+        "        use super::super::{{native_isa, Path, WastContext, Compiler, Features, CompilationStrategy}};"
-    )?;
+    )
-    for dir_entry in dir_entries {
-        write_testsuite_tests(out, &dir_entry.path(), testsuite)?;
-    }
-    writeln!(out, "}}")?;
-    Ok(())
 }
 
-fn test_file(out: &mut File, testfile: &str) -> io::Result<()> {
+fn finish_test_module(out: &mut File) -> io::Result<()> {
-    let path = Path::new(testfile);
+    writeln!(out, "    }}")
-    write_testsuite_tests(out, path, "single_file_spec_test")
 }
 
-fn write_testsuite_tests(out: &mut File, path: &Path, testsuite: &str) -> io::Result<()> {
+fn write_testsuite_tests(
+    out: &mut File,
+    path: &Path,
+    testsuite: &str,
+    strategy: &str,
+) -> io::Result<()> {
     let stemstr = path
         .file_stem()
         .expect("file_stem")
@@ -78,12 +105,16 @@ fn write_testsuite_tests(out: &mut File, path: &Path, testsuite: &str) -> io::Re
         .expect("to_str");
 
     writeln!(out, "        #[test]")?;
-    if ignore(testsuite, stemstr) {
+    if ignore(testsuite, stemstr, strategy) {
         writeln!(out, "        #[ignore]")?;
     }
     writeln!(out, "        fn r#{}() {{", &stemstr.replace("-", "_"))?;
     writeln!(out, "            let isa = native_isa();")?;
-    writeln!(out, "        let compiler = Compiler::new(isa);")?;
+    writeln!(
+        out,
+        "            let compiler = Compiler::new(isa, CompilationStrategy::{});",
+        strategy
+    )?;
     writeln!(
         out,
         "            let features = Features {{ simd: true, ..Default::default() }};"
@@ -113,7 +144,39 @@ fn write_testsuite_tests(out: &mut File, path: &Path, testsuite: &str) -> io::Re
 }
 
 /// Ignore tests that aren't supported yet.
-fn ignore(testsuite: &str, name: &str) -> bool {
+fn ignore(testsuite: &str, name: &str, strategy: &str) -> bool {
+    match strategy {
+        #[cfg(feature = "lightbeam")]
+        "AlwaysLightbeam" => match (testsuite, name) {
+            ("misc_testsuite", "memory_grow")
+            | ("misc_testsuite", "misc_traps")
+            | ("single_file_spec_test", "simd_const")
+            | ("spec_testsuite", "address")
+            | ("spec_testsuite", "align")
+            | ("spec_testsuite", "call")
+            | ("spec_testsuite", "call_indirect")
+            | ("spec_testsuite", "conversions")
+            | ("spec_testsuite", "elem")
+            | ("spec_testsuite", "func_ptrs")
+            | ("spec_testsuite", "globals")
+            | ("spec_testsuite", "i32")
+            | ("spec_testsuite", "i64")
+            | ("spec_testsuite", "if")
+            | ("spec_testsuite", "imports")
+            | ("spec_testsuite", "int_exprs")
+            | ("spec_testsuite", "linking")
+            | ("spec_testsuite", "memory_grow")
+            | ("spec_testsuite", "memory_trap")
+            | ("spec_testsuite", "select")
+            | ("spec_testsuite", "traps")
+            | ("spec_testsuite", "unreachable")
+            | ("spec_testsuite", "unwind") => return true,
+            _ => (),
+        },
+        "AlwaysCranelift" => {}
+        _ => panic!("unrecognized strategy"),
+    }
+
     if cfg!(windows) {
         return match (testsuite, name) {
             ("spec_testsuite", "address") => true,

misc/wasmtime-py/src/lib.rs

@@ -69,7 +69,7 @@ pub fn instantiate(
         isa_builder.finish(cranelift_codegen::settings::Flags::new(flag_builder))
     };
 
-    let mut context = wasmtime_jit::Context::with_isa(isa);
+    let mut context = wasmtime_jit::Context::with_isa(isa, wasmtime_jit::CompilationStrategy::Auto);
     context.set_debug_info(generate_debug_info);
     let global_exports = context.get_global_exports();
 

src/bin/wast.rs

@@ -34,14 +34,14 @@ use serde::Deserialize;
 use std::path::Path;
 use std::process;
 use wasmtime_environ::{cache_create_new_config, cache_init};
-use wasmtime_jit::{Compiler, Features};
+use wasmtime_jit::{CompilationStrategy, Compiler, Features};
 use wasmtime_wast::WastContext;
 
 const USAGE: &str = "
 Wast test runner.
 
 Usage:
-    wast [-do] [--enable-simd] [--disable-cache | --cache-config=<cache_config_file>] <file>...
+    wast [-do] [--enable-simd] [--disable-cache | --cache-config=<cache_config_file>] [--always-lightmean | --always-cranelift] <file>...
     wast --create-cache-config [--cache-config=<cache_config_file>]
     wast --help | --version
 
@@ -57,6 +57,8 @@ Options:
                         creates default configuration and writes it to the disk,
                         use with --cache-config to specify custom config file
                         instead of default one
+    --always-lightbeam  use Lightbeam for all compilation
+    --always-cranelift  use Cranelift for all compilation
     -d, --debug         enable debug output on stderr/stdout
     --enable-simd       enable proposed SIMD instructions
 ";
@@ -71,6 +73,8 @@ struct Args {
     flag_cache_config: Option<String>,
     flag_create_cache_config: bool,
     flag_enable_simd: bool,
+    flag_always_lightbeam: bool,
+    flag_always_cranelift: bool,
 }
 
 fn main() {
@@ -148,8 +152,18 @@ fn main() {
         features.simd = true;
     }
 
+    // Decide how to compile.
+    let strategy = match (args.flag_always_lightbeam, args.flag_always_cranelift) {
+        (true, false) => CompilationStrategy::AlwaysLightbeam,
+        (false, true) => CompilationStrategy::AlwaysCranelift,
+        (false, false) => CompilationStrategy::Auto,
+        (true, true) => {
+            panic!("Can't enable --always-cranelift and --always-lightbeam at the same time")
+        }
+    };
+
     let isa = isa_builder.finish(settings::Flags::new(flag_builder));
-    let engine = Compiler::new(isa);
+    let engine = Compiler::new(isa, strategy);
     let mut wast_context = WastContext::new(Box::new(engine)).with_features(features);
 
     wast_context

tests/instantiate.rs

@@ -8,7 +8,7 @@ use std::io::Read;
 use std::path::PathBuf;
 use std::rc::Rc;
 use wabt;
-use wasmtime_jit::{instantiate, Compiler, NullResolver};
+use wasmtime_jit::{instantiate, CompilationStrategy, Compiler, NullResolver};
 
 #[cfg(test)]
 const PATH_MODULE_RS2WASM_ADD_FUNC: &str = r"filetests/rs2wasm-add-func.wat";
@@ -40,7 +40,7 @@ fn test_environ_translate() {
     let isa = isa_builder.finish(settings::Flags::new(flag_builder));
 
     let mut resolver = NullResolver {};
-    let mut compiler = Compiler::new(isa);
+    let mut compiler = Compiler::new(isa, CompilationStrategy::Auto);
     let global_exports = Rc::new(RefCell::new(HashMap::new()));
     let instance = instantiate(&mut compiler, &data, &mut resolver, global_exports, false);
     assert!(instance.is_ok());

tests/wast_testsuites.rs

@@ -4,7 +4,7 @@ use cranelift_codegen::isa;
 use cranelift_codegen::settings;
 use cranelift_codegen::settings::Configurable;
 use std::path::Path;
-use wasmtime_jit::{Compiler, Features};
+use wasmtime_jit::{CompilationStrategy, Compiler, Features};
 use wasmtime_wast::WastContext;
 
 include!(concat!(env!("OUT_DIR"), "/wast_testsuite_tests.rs"));

wasmtime-api/src/context.rs

@@ -2,7 +2,7 @@ use std::cell::{RefCell, RefMut};
 use std::hash::{Hash, Hasher};
 use std::rc::Rc;
 
-use wasmtime_jit::{Compiler, Features};
+use wasmtime_jit::{CompilationStrategy, Compiler, Features};
 
 use cranelift_codegen::settings;
 
@@ -59,5 +59,5 @@ pub(crate) fn create_compiler(flags: settings::Flags) -> Compiler {
         isa_builder.finish(flags)
     };
 
-    Compiler::new(isa)
+    Compiler::new(isa, CompilationStrategy::Auto)
 }

wasmtime-jit/src/compiler.rs

@@ -25,6 +25,20 @@ use wasmtime_runtime::{
     VMFunctionBody,
 };
 
+/// Select which kind of compilation to use.
+#[derive(Copy, Clone, Debug)]
+pub enum CompilationStrategy {
+    /// Let Wasmtime pick the strategy.
+    Auto,
+
+    /// Compile all functions with Cranelift.
+    AlwaysCranelift,
+
+    /// Compile all functions with Lightbeam.
+    #[cfg(feature = "lightbeam")]
+    AlwaysLightbeam,
+}
+
 /// A WebAssembly code JIT compiler.
 ///
 /// A `Compiler` instance owns the executable memory that it allocates.
@@ -40,6 +54,7 @@ pub struct Compiler {
     trap_registration_guards: Vec<TrapRegistrationGuard>,
     trampoline_park: HashMap<*const VMFunctionBody, *const VMFunctionBody>,
     signatures: SignatureRegistry,
+    strategy: CompilationStrategy,
 
     /// The `FunctionBuilderContext`, shared between trampline function compilations.
     fn_builder_ctx: FunctionBuilderContext,
@@ -47,7 +62,7 @@ pub struct Compiler {
 
 impl Compiler {
     /// Construct a new `Compiler`.
-    pub fn new(isa: Box<dyn TargetIsa>) -> Self {
+    pub fn new(isa: Box<dyn TargetIsa>, strategy: CompilationStrategy) -> Self {
         Self {
             isa,
             code_memory: CodeMemory::new(),
@@ -55,6 +70,7 @@ impl Compiler {
             trampoline_park: HashMap::new(),
             signatures: SignatureRegistry::new(),
             fn_builder_ctx: FunctionBuilderContext::new(),
+            strategy,
         }
     }
 }
@@ -73,11 +89,6 @@ impl Drop for Compiler {
     }
 }
 
-#[cfg(feature = "lightbeam")]
-type DefaultCompiler = wasmtime_environ::lightbeam::Lightbeam;
-#[cfg(not(feature = "lightbeam"))]
-type DefaultCompiler = wasmtime_environ::cranelift::Cranelift;
-
 impl Compiler {
     /// Return the target's frontend configuration settings.
     pub fn frontend_config(&self) -> TargetFrontendConfig {
@@ -105,12 +116,27 @@ impl Compiler {
         SetupError,
     > {
         let (compilation, relocations, address_transform, value_ranges, stack_slots, traps) =
-            DefaultCompiler::compile_module(
+            match self.strategy {
+                // For now, interpret `Auto` as `AlwaysCranelift` since that's the most stable
+                // implementation.
+                CompilationStrategy::Auto | CompilationStrategy::AlwaysCranelift => {
+                    wasmtime_environ::cranelift::Cranelift::compile_module(
                         module,
                         function_body_inputs,
                         &*self.isa,
                         debug_data.is_some(),
                     )
+                }
+                #[cfg(feature = "lightbeam")]
+                CompilationStrategy::AlwaysLightbeam => {
+                    wasmtime_environ::lightbeam::Lightbeam::compile_module(
+                        module,
+                        function_body_inputs,
+                        &*self.isa,
+                        debug_data.is_some(),
+                    )
+                }
+            }
             .map_err(SetupError::Compile)?;
 
         let allocated_functions =

wasmtime-jit/src/context.rs

@@ -1,7 +1,7 @@
 use crate::action::{get, inspect_memory, invoke};
 use crate::{
-    instantiate, ActionError, ActionOutcome, Compiler, InstanceHandle, Namespace, RuntimeValue,
+    instantiate, ActionError, ActionOutcome, CompilationStrategy, Compiler, InstanceHandle,
-    SetupError,
+    Namespace, RuntimeValue, SetupError,
 };
 use cranelift_codegen::isa::TargetIsa;
 use std::boxed::Box;
@@ -103,8 +103,8 @@ impl Context {
     }
 
     /// Construct a new instance of `Context` with the given target.
-    pub fn with_isa(isa: Box<dyn TargetIsa>) -> Self {
+    pub fn with_isa(isa: Box<dyn TargetIsa>, strategy: CompilationStrategy) -> Self {
-        Self::new(Box::new(Compiler::new(isa)))
+        Self::new(Box::new(Compiler::new(isa, strategy)))
     }
 
     /// Retrieve the context features

wasmtime-jit/src/lib.rs

@@ -49,7 +49,7 @@ mod resolver;
 mod target_tunables;
 
 pub use crate::action::{ActionError, ActionOutcome, RuntimeValue};
-pub use crate::compiler::Compiler;
+pub use crate::compiler::{CompilationStrategy, Compiler};
 pub use crate::context::{Context, ContextError, Features, UnknownInstance};
 pub use crate::instantiate::{instantiate, CompiledModule, SetupError};
 pub use crate::link::link_module;