make wasi support optional

.github/workflows/ci.yml

@@ -47,6 +47,10 @@ jobs:
         run: |
           zig build -Dvm_kind=${{ matrix.stack_kind }}
 
+      - name: Build (no wasi)
+        run: |
+          zig build -Dvm_kind=${{ matrix.stack_kind }} -Dwasi=false
+
       - name: Bench
         run: |
           zig build bench -Dvm_kind=${{ matrix.stack_kind }} -Doptimize=ReleaseFast

build.zig

@@ -41,9 +41,15 @@ pub fn build(b: *Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
-    const enable_metering = b.option(bool, "meter", "Enable metering") orelse false;
-    const enable_debug_trace = b.option(bool, "debug_trace", "Enable debug tracing feature") orelse false;
-    const enable_debug_trap = b.option(bool, "debug_trap", "Enable debug trap features") orelse false;
+    const enable_metering = b.option(bool, "meter", "Enable metering (default: false)") orelse false;
+    const enable_debug_trace = b.option(bool, "debug_trace", "Enable debug tracing feature (default: false)") orelse false;
+    const enable_debug_trap = b.option(bool, "debug_trap", "Enable debug trap features (default: false)") orelse false;
+    const enable_wasi = b.option(bool, "wasi", "Enable wasi support (default: true if target has support)") orelse blk: {
+        if (target.result.cpu.arch.isWasm() and target.result.os.tag != .wasi) {
+            break :blk false;
+        }
+        break :blk true;
+    };
     const vm_kind = b.option(
         StackVmKind,
         "vm_kind",
@@ -54,6 +60,7 @@ pub fn build(b: *Build) void {
     options.addOption(bool, "enable_metering", enable_metering);
     options.addOption(bool, "enable_debug_trace", enable_debug_trace);
     options.addOption(bool, "enable_debug_trap", enable_debug_trap);
+    options.addOption(bool, "enable_wasi", enable_wasi);
     options.addOption(StackVmKind, "vm_kind", vm_kind);
 
     const stable_array = b.dependency("zig-stable-array", .{
@@ -150,12 +157,15 @@ pub fn build(b: *Build) void {
     });
 
     // wasi tests
-    const wasi_testsuite = b.addSystemCommand(&.{"python3"});
-    wasi_testsuite.addArg("test/wasi/run.py");
-    wasi_testsuite.step.dependOn(bytebox_exe_step);
-
-    const wasi_testsuite_step = b.step("test-wasi", "Run wasi testsuite");
-    wasi_testsuite_step.dependOn(&wasi_testsuite.step);
+    var maybe_wasi_testsuite_step: ?*Step = null;
+    if (enable_wasi) {
+        const wasi_testsuite = b.addSystemCommand(&.{"python3"});
+        wasi_testsuite.addArg("test/wasi/run.py");
+        wasi_testsuite.step.dependOn(bytebox_exe_step);
+
+        maybe_wasi_testsuite_step = b.step("test-wasi", "Run wasi testsuite");
+        maybe_wasi_testsuite_step.?.dependOn(&wasi_testsuite.step);
+    }
 
     // mem64 test
     const compile_mem64_test: WasmBuild = buildWasmExe(b, "test/mem64/memtest.zig", .wasm64);
@@ -197,9 +207,11 @@ pub fn build(b: *Build) void {
     const all_tests_step = b.step("test", "Run unit, wasm, and wasi tests");
     all_tests_step.dependOn(unit_test_step);
     all_tests_step.dependOn(wasm_testsuite_step);
-    all_tests_step.dependOn(wasi_testsuite_step);
     all_tests_step.dependOn(mem64_test_step);
     all_tests_step.dependOn(cffi_test_step);
+    if (maybe_wasi_testsuite_step) |wasi_testsuite_step| {
+        all_tests_step.dependOn(wasi_testsuite_step);
+    }
 }
 
 fn buildExeWithRunStep(b: *Build, target: Build.ResolvedTarget, optimize: std.builtin.OptimizeMode, imports: []const Import, opts: ExeOpts) *Build.Step {

run/main.zig

@@ -257,12 +257,24 @@ pub fn main() !void {
     var module_instance = try bytebox.createModuleInstance(.Stack, module_def, allocator);
     defer module_instance.destroy();
 
-    var imports_wasi: bytebox.ModuleImportPackage = try wasi.initImports(.{
-        .argv = opts.wasm_argv,
-        .env = opts.wasm_env,
-        .dirs = opts.wasm_dirs,
-    }, allocator);
-    defer wasi.deinitImports(&imports_wasi);
+    var imports_wasi: bytebox.ModuleImportPackage = blk: {
+        if (config.enable_wasi) {
+            break :blk try wasi.initImports(.{
+                .argv = opts.wasm_argv,
+                .env = opts.wasm_env,
+                .dirs = opts.wasm_dirs,
+            }, allocator);
+        } else {
+            break :blk try bytebox.ModuleImportPackage.init("empty_stub", null, null, allocator);
+        }
+    };
+    defer {
+        if (config.enable_wasi) {
+            wasi.deinitImports(&imports_wasi);
+        } else {
+            imports_wasi.deinit();
+        }
+    }
 
     const instantiate_opts = bytebox.ModuleInstantiateOpts{
         .imports = &[_]bytebox.ModuleImportPackage{imports_wasi},

src/core.zig

@@ -5,7 +5,7 @@ const inst = @import("instance.zig");
 const vm_stack = @import("vm_stack.zig");
 const vm_register = @import("vm_register.zig");
 pub const config = @import("config");
-pub const wasi = @import("wasi.zig");
+pub const wasi = if (config.enable_wasi) @import("wasi.zig") else void;
 
 pub const LogLevel = common.LogLevel;
 pub const Logger = common.Logger;

src/definition.zig

@@ -11,12 +11,6 @@ const opcodes = @import("opcode.zig");
 const Opcode = opcodes.Opcode;
 const WasmOpcode = opcodes.WasmOpcode;
 
-// HACK: just get the code working, will need to resolve anything dependent on this eventually
-const inst = @import("instance.zig");
-const ModuleInstance = inst.ModuleInstance;
-const Store = inst.Store;
-const GlobalInstance = inst.GlobalInstance;
-
 pub const MalformedError = error{
     MalformedBytecode,
     MalformedCustomSection,