runtime/wasm: add opt-in non-moving collector (based on #2197)

.github/actions/setup-binaryen/action.yml

@@ -0,0 +1,40 @@
+name: "Setup Binaryen"
+description: "Install a pinned Binaryen release"
+inputs:
+  version:
+    description: "Binaryen release version"
+    required: false
+    default: "131"
+
+runs:
+  using: "composite"
+  steps:
+    - name: Install Binaryen
+      shell: bash
+      run: |
+        set -euo pipefail
+
+        version="${{ inputs.version }}"
+        case "$(uname -s):$(uname -m)" in
+          Linux:x86_64) platform="x86_64-linux" ;;
+          Linux:aarch64|Linux:arm64) platform="aarch64-linux" ;;
+          Darwin:x86_64) platform="x86_64-macos" ;;
+          Darwin:arm64) platform="arm64-macos" ;;
+          *)
+            echo "Unsupported Binaryen host: $(uname -s) $(uname -m)" >&2
+            exit 1
+            ;;
+        esac
+
+        archive="binaryen-version_${version}-${platform}.tar.gz"
+        base_url="https://github.com/WebAssembly/binaryen/releases/download/version_${version}"
+        cd "$RUNNER_TEMP"
+        curl --retry 3 --retry-all-errors -fsSLO "${base_url}/${archive}"
+        curl --retry 3 --retry-all-errors -fsSLO "${base_url}/${archive}.sha256"
+        if command -v sha256sum >/dev/null; then
+          sha256sum --check "${archive}.sha256"
+        else
+          shasum -a 256 --check "${archive}.sha256"
+        fi
+        tar -xzf "$archive" -C "$RUNNER_TEMP"
+        echo "$RUNNER_TEMP/binaryen-version_${version}/bin" >> "$GITHUB_PATH"

.github/workflows/build-cache.yml

@@ -35,6 +35,9 @@ jobs:
       - name: Set up Go
         uses: ./.github/actions/setup-go
 
+      - name: Set up Binaryen
+        uses: ./.github/actions/setup-binaryen
+
       - name: Install wamr (for wasm tests)
         if: startsWith(matrix.os, 'macos')
         run: |

.github/workflows/llgo.yml

@@ -180,7 +180,9 @@ jobs:
   test:
     name: test (${{ matrix.lane }}, ${{ matrix.os }}, LLVM ${{ matrix.llvm }}, Go ${{ matrix.go }}, shard ${{ matrix.shard }})
     continue-on-error: ${{ matrix.lane == 'compatibility' }}
-    timeout-minutes: 30
+    # macOS runs the full package set in one shard and is normally just over
+    # 30 minutes once the wasm runtime sources are present.
+    timeout-minutes: 40
     strategy:
       matrix:
         # Keep compatibility and primary toolchains pinned to exact patches.
@@ -366,6 +368,9 @@ jobs:
       - name: Set up Go for building llgo
         uses: ./.github/actions/setup-go
 
+      - name: Set up Binaryen
+        uses: ./.github/actions/setup-binaryen
+
       - name: Install wamr
         run: |
           git clone --branch WAMR-2.4.4 --depth 1 https://github.com/bytecodealliance/wasm-micro-runtime.git
@@ -414,6 +419,24 @@ jobs:
         with:
           version: "4.0.21"
 
+      - name: Set up Node.js
+        uses: actions/setup-node@v7
+        with:
+          node-version: "25"
+
+      - name: Set up Binaryen
+        uses: ./.github/actions/setup-binaryen
+
+      - name: Set up Wasmtime
+        uses: bytecodealliance/actions/wasmtime/setup@v1
+        with:
+          version: "39.0.1"
+
+      - name: Set up wasm-tools
+        uses: bytecodealliance/actions/wasm-tools/setup@v1
+        with:
+          version: "1.243.0"
+
       - name: Set up Go for building llgo
         uses: ./.github/actions/setup-go
 
@@ -430,6 +453,50 @@ jobs:
       - name: Build standard runtime for wasm
         shell: bash
         run: |
+          run_wasm_scheduler() {
+            local module="$1"
+            local output
+            node --input-type=module -e "import Module from '$module'; await Module();"
+            if output=$(node --input-type=module -e "import Module from '$module'; await Module({preRun: [module => { module.ENV.LLGO_WASM_SCHEDULER_DEADLOCK = '1'; }]});" 2>&1); then
+              echo "deadlock scheduler fixture unexpectedly succeeded"
+              return 1
+            fi
+            grep -Fq "fatal error: all goroutines are asleep - deadlock!" <<<"$output"
+          }
+
+          run_wasi_scheduler() {
+            local module="$1"
+            local output
+            wasm-tools validate --features all "$module"
+            output=$(wasmtime run -W exceptions=y "$module" 2>&1)
+            grep -Fq "wasm scheduler ok" <<<"$output"
+            if output=$(wasmtime run -W exceptions=y \
+              --env LLGO_WASM_SCHEDULER_DEADLOCK=1 "$module" 2>&1); then
+              echo "deadlock scheduler fixture unexpectedly succeeded"
+              return 1
+            fi
+            grep -Fq "fatal error: all goroutines are asleep - deadlock!" <<<"$output"
+          }
+
           GOOS=js GOARCH=wasm llgo build -o "$RUNNER_TEMP/runtime-js.wasm" ./internal/build/testdata/wasm-runtime
           GOOS=wasip1 GOARCH=wasm llgo build -o "$RUNNER_TEMP/runtime-wasip1.wasm" ./internal/build/testdata/wasm-runtime
-          file "$RUNNER_TEMP/runtime-js.wasm" "$RUNNER_TEMP/runtime-wasip1.wasm"
+          LLGO_WASI_THREADS=1 GOOS=wasip1 GOARCH=wasm llgo build \
+            -o "$RUNNER_TEMP/runtime-wasip1-threads.wasm" ./internal/build/testdata/wasm-runtime
+          test "$(wasmtime run -W exceptions=y "$RUNNER_TEMP/runtime-wasip1.wasm" 2>&1)" = "wasip1"
+          GOOS=js GOARCH=wasm llgo build -o "$RUNNER_TEMP/wasm-scheduler-go.mjs" ./internal/build/testdata/wasm-scheduler
+          run_wasm_scheduler "$RUNNER_TEMP/wasm-scheduler-go.mjs"
+          llgo build -target wasm -o "$RUNNER_TEMP/wasm-scheduler.mjs" ./internal/build/testdata/wasm-scheduler
+          run_wasm_scheduler "$RUNNER_TEMP/wasm-scheduler.mjs"
+          GOOS=wasip1 GOARCH=wasm llgo build -o "$RUNNER_TEMP/wasm-scheduler-wasip1.wasm" ./internal/build/testdata/wasm-scheduler
+          run_wasi_scheduler "$RUNNER_TEMP/wasm-scheduler-wasip1.wasm"
+          GOOS=js GOARCH=wasm llgo build -tags=llgo_wasm_gc -o "$RUNNER_TEMP/wasm-gc-go.mjs" ./internal/build/testdata/wasm-gc
+          node --input-type=module -e "import Module from '$RUNNER_TEMP/wasm-gc-go.mjs'; await Module();"
+          llgo build -target wasm -tags=llgo_wasm_gc -o "$RUNNER_TEMP/wasm-gc.mjs" ./internal/build/testdata/wasm-gc
+          node --input-type=module -e "import Module from '$RUNNER_TEMP/wasm-gc.mjs'; await Module();"
+          GOOS=wasip1 GOARCH=wasm LLGO_WASI_THREADS=0 llgo build -tags=llgo_wasm_gc -o "$RUNNER_TEMP/wasm-gc-wasip1.wasm" ./internal/build/testdata/wasm-gc
+          wasm-tools validate --features all "$RUNNER_TEMP/wasm-gc-wasip1.wasm"
+          test "$(wasmtime run -W exceptions=y "$RUNNER_TEMP/wasm-gc-wasip1.wasm" 2>&1)" = "wasm gc ok"
+          file "$RUNNER_TEMP/runtime-js.wasm" \
+            "$RUNNER_TEMP/runtime-wasip1.wasm" \
+            "$RUNNER_TEMP/runtime-wasip1-threads.wasm" \
+            "$RUNNER_TEMP/wasm-gc-wasip1.wasm"

.github/workflows/targets.yml

@@ -29,6 +29,11 @@ jobs:
         with:
           llvm-version: ${{matrix.llvm}}
 
+      - name: Set up Emscripten
+        uses: emscripten-core/setup-emsdk@v15
+        with:
+          version: "4.0.21"
+
       - name: Set up Go for build
         uses: ./.github/actions/setup-go
 

internal/build/build.go

@@ -36,6 +36,7 @@ import (
 	"strings"
 	"sync"
 	"sync/atomic"
+	"unicode"
 
 	"golang.org/x/tools/go/ssa"
 
@@ -298,9 +299,6 @@ func Do(args []string, conf *Config) ([]Package, error) {
 	if conf.Goarch == "" {
 		conf.Goarch = runtime.GOARCH
 	}
-	if conf.AppExt == "" {
-		conf.AppExt = defaultAppExt(conf)
-	}
 	if conf.BuildMode == "" {
 		conf.BuildMode = BuildModeExe
 	}
@@ -339,6 +337,12 @@ func Do(args []string, conf *Config) ([]Package, error) {
 	if conf.Target != "" && export.GOARCH != "" {
 		conf.Goarch = export.GOARCH
 	}
+	if err := configureWasmGC(conf, &export); err != nil {
+		return nil, err
+	}
+	if conf.AppExt == "" {
+		conf.AppExt = defaultAppExt(conf)
+	}
 	if err := validateLinkOptions(conf, &export); err != nil {
 		return nil, err
 	}
@@ -418,10 +422,7 @@ func Do(args []string, conf *Config) ([]Package, error) {
 	// final-PC sites for sidecar construction.
 	prog.EnableFuncInfoSites(shouldEnablePCLNSites(conf, funcInfo, emitDebugInfo))
 	sizes := func(sizes types.Sizes, compiler, arch string) types.Sizes {
-		if arch == "wasm" {
-			sizes = &types.StdSizes{WordSize: 4, MaxAlign: 4}
-		}
-		return prog.TypeSizes(sizes)
+		return prog.TypeSizes(effectiveTypeSizes(sizes, conf.Goos, arch, conf.Target))
 	}
 	dedup := packages.NewDeduper()
 	var syntaxErr error
@@ -727,16 +728,52 @@ func DefaultBuildTags(goarch, target string) string {
 
 func defaultBuildTags(goarch, target string) string {
 	tags := "llgo,math_big_pure_go,purego"
-	// Raw GOOS/GOARCH wasm builds do not have a target configuration that
-	// selects a collector. BDWGC is not available in either wasm host, so use
-	// the supported collector-free runtime unless a named target supplies its
-	// own runtime configuration.
-	if goarch == "wasm" && target == "" {
+	// BDWGC is unavailable in both wasm hosts.
+	if goarch == "wasm" {
 		tags += ",nogc"
 	}
 	return tags
 }
 
+func configureWasmGC(conf *Config, export *crosscompile.Export) error {
+	if conf.Goarch != "wasm" || !hasBuildTag(conf.Tags, "llgo_wasm_gc") {
+		return nil
+	}
+	switch conf.Goos {
+	case "js":
+		if !slices.Contains(export.LDFLAGS, "-sMALLOC=none") {
+			export.LDFLAGS = append(export.LDFLAGS, "-sMALLOC=none")
+		}
+	case "wasip1":
+		if IsWasiThreadsEnabled() {
+			return errors.New("llgo_wasm_gc requires single-worker WASI (set LLGO_WASI_THREADS=0)")
+		}
+	default:
+		return fmt.Errorf("llgo_wasm_gc does not support GOOS=%s", conf.Goos)
+	}
+	return nil
+}
+
+func hasBuildTag(tags, want string) bool {
+	for _, tag := range strings.FieldsFunc(tags, func(r rune) bool {
+		return r == ',' || unicode.IsSpace(r)
+	}) {
+		if tag == want {
+			return true
+		}
+	}
+	return false
+}
+
+func effectiveTypeSizes(sizes types.Sizes, goos, goarch, target string) types.Sizes {
+	// Named wasm targets use the native wasm32 data model. The raw js/wasm
+	// entry point keeps Go's 64-bit word model and is emitted as Memory64.
+	if goarch == "wasm" && (target != "" || goos != "js") {
+		return &types.StdSizes{WordSize: 4, MaxAlign: 4}
+	}
+	return sizes
+}
+
 func allowMissingFunctionBodies(initial []*packages.Package) {
 	for _, pkg := range initial {
 		hasMissingBody := false
@@ -1359,12 +1396,15 @@ func linkMainPkg(ctx *context, pkg *packages.Package, pkgs []*aPackage, outputPa
 	}
 	linkArgs = append(linkArgs, cSharedExportArgs(ctx, linkedOrder)...)
 
-	err = linkObjFiles(ctx, outputPath, linkInputs, linkArgs, verbose)
+	linkOutput, err := prepareWasmLinkOutput(ctx.buildConf, &ctx.crossCompile, outputPath)
 	if err != nil {
 		return err
 	}
-
-	return nil
+	defer cleanupWasmLinkOutput(linkOutput, outputPath)
+	if err := linkObjFiles(ctx, linkOutput, linkInputs, linkArgs, verbose); err != nil {
+		return err
+	}
+	return publishWasmLinkOutput(ctx, linkOutput, outputPath, verbose)
 }
 
 func linkedModuleGlobals(pkgs []Package) map[string]none {
@@ -2360,7 +2400,7 @@ func llvmPassPipeline(level optlevel.Level, ltoMode lto.Mode) string {
 }
 
 func IsWasiThreadsEnabled() bool {
-	return isEnvOn(llgoWasiThreads, true)
+	return isEnvOn(llgoWasiThreads, false)
 }
 
 func IsFullRpathEnabled() bool {