Add option to use weval, an experimental JS AOT option using partia…

…l evaluation. This PR pulls in some still-experimental work to partially evaluate the SpiderMonkey JS interpreter together with JS scripts, ahead-of-time, to produce compiled code. It should not yet be considered production-worthy, pending more testing and proving out its stability and performance; but, it is at a point where we believe it should be under a *non-default* option so that users of the SDK may try it. No guarantees! It may explode your bytecode! The support works by bundling two builds of the engine Wasm -- with and without the weval intrinsics -- and invoking either Wizer with the "normal" build or weval with the "weval" build, as appropriate. The `--enable-weval` option selects the latter.
fastly · cfallin · May 12, 2023 · May 26, 2023 · Jun 2, 2023 · Jun 2, 2023
commit 88638f719d700d530a4a6a410ed3f36295ebb3f0
diff --git a/js-compute-runtime-cli.js b/js-compute-runtime-cli.js
@@ -7,6 +7,7 @@ import { addSdkMetadataField } from "./src/addSdkMetadataField.js";
 
 const {
   enableExperimentalHighResolutionTimeMethods,
+  enableWeval,
   wasmEngine,
   input,
   component,
@@ -27,7 +28,7 @@ if (version) {
   // it could be that the user is using an older version of js-compute-runtime
   // and a newer version does not support the platform they are using.
   const {compileApplicationToWasm} = await import('./src/compileApplicationToWasm.js')
-  await compileApplicationToWasm(input, output, wasmEngine, enableExperimentalHighResolutionTimeMethods);
+  await compileApplicationToWasm(input, output, wasmEngine, enableExperimentalHighResolutionTimeMethods, enableWeval);
   if (component) {
     const {compileComponent} = await import('./src/component.js');
     await compileComponent(output);

diff --git a/package.json b/package.json
@@ -31,8 +31,8 @@
     "test": "npm run test:types && npm run test:cli",
     "test:cli": "brittle --bail integration-tests/cli/**.test.js",
     "test:types": "tsd",
-    "build": "make -j8 -C runtime/js-compute-runtime && cp runtime/js-compute-runtime/*.wasm runtime/js-compute-runtime/fastly.wit .",
-    "build:debug": "DEBUG=true make -j8 -C runtime/js-compute-runtime && cp runtime/js-compute-runtime/*.wasm runtime/js-compute-runtime/fastly.wit .",
+    "build": "make -j8 -C runtime/js-compute-runtime && make -j8 -C runtime/js-compute-runtime VARIANT=-weval && cp runtime/js-compute-runtime/*.wasm runtime/js-compute-runtime/fastly.wit .",
+    "build:debug": "DEBUG=true make -j8 -C runtime/js-compute-runtime && make -j8 -C runtime/js-compute-runtime VARIANT=-weval && cp runtime/js-compute-runtime/*.wasm runtime/js-compute-runtime/fastly.wit .",
     "check-changelog": "cae-release-notes-format-checker CHANGELOG.md"
   },
   "devDependencies": {
@@ -47,6 +47,7 @@
   "dependencies": {
     "@bytecodealliance/jco": "^0.7.0",
     "@bytecodealliance/wizer": "^3.0.1",
+    "@cfallin/weval": "^0.1.3",
     "acorn": "^8.8.2",
     "acorn-walk": "^8.2.0",
     "esbuild": "^0.17.18",

diff --git a/runtime/js-compute-runtime/Makefile b/runtime/js-compute-runtime/Makefile
@@ -67,6 +67,9 @@ else
   WASM_STRIP = wasm-opt --strip-debug -o $1 $1
 endif
 
+# The build variant (normal or weval).
+VARIANT ?= -normal
+
 # The path to the wasm-tools executable
 WASM_TOOLS ?= $(shell which wasm-tools)
 
@@ -80,10 +83,10 @@ endif
 BUILD := $(FSM_SRC)/build
 
 # The output directory for the current build mode (relase/debug).
-OBJ_DIR := $(BUILD)/$(MODE)
+OBJ_DIR := $(BUILD)/$(MODE)$(VARIANT)
 
 # The path to the //runtime/spidermonkey/$(MODE) directory.
-SM_SRC := $(ROOT_SRC)/spidermonkey/$(MODE)
+SM_SRC := $(ROOT_SRC)/spidermonkey/$(MODE)$(VARIANT)
 
 # The objects we link in from spidermonkey
 SM_OBJ := $(wildcard $(SM_SRC)/lib/*.o)
@@ -121,14 +124,16 @@ LD_FLAGS += -L$(BUILD)/openssl/libx32 -lcrypto
 # Default targets ##############################################################
 
 .PHONY: all
-all: $(FSM_SRC)/js-compute-runtime.wasm
-all: $(FSM_SRC)/js-compute-runtime-component.wasm
+all: $(FSM_SRC)/js-compute-runtime$(VARIANT).wasm
+all: $(FSM_SRC)/js-compute-runtime-component$(VARIANT).wasm
 
 # Remove just the build artifacts for the current runtime build.
 .PHONY: clean
 clean:
-	$(call cmd,rm,$(FSM_SRC)/js-compute-runtime.wasm)
-	$(call cmd,rm,$(FSM_SRC)/js-compute-runtime-component.wasm)
+	$(call cmd,rm,$(FSM_SRC)/js-compute-runtime-normal.wasm)
+	$(call cmd,rm,$(FSM_SRC)/js-compute-runtime-component-normal.wasm)
+	$(call cmd,rm,$(FSM_SRC)/js-compute-runtime-weval.wasm)
+	$(call cmd,rm,$(FSM_SRC)/js-compute-runtime-component-weval.wasm)
 	$(call cmd,rmdir,$(BUILD)/release)
 	$(call cmd,rmdir,$(BUILD)/debug)
 
@@ -304,9 +309,9 @@ $(eval $(call compile_cxx,$(FSM_SRC)/fastly-world/fastly_world_adapter.cpp))
 # NOTE: we shadow wasm-opt by adding $(FSM_SRC)/scripts to the path, which
 # includes a script called wasm-opt that immediately exits successfully. See
 # that script for more information about why we do this.
-$(OBJ_DIR)/js-compute-runtime.wasm: $(FSM_OBJ) $(SM_OBJ) $(RUST_URL_LIB) $(RUST_ENCODING_LIB)
-$(OBJ_DIR)/js-compute-runtime.wasm: $(OBJ_DIR)/impl/main.o
-$(OBJ_DIR)/js-compute-runtime.wasm: $(OBJ_DIR)/fastly-world/fastly_world_adapter.o
+$(OBJ_DIR)/js-compute-runtime$(VARIANT).wasm: $(FSM_OBJ) $(SM_OBJ) $(RUST_URL_LIB) $(RUST_ENCODING_LIB)
+$(OBJ_DIR)/js-compute-runtime$(VARIANT).wasm: $(OBJ_DIR)/impl/main.o
+$(OBJ_DIR)/js-compute-runtime$(VARIANT).wasm: $(OBJ_DIR)/fastly-world/fastly_world_adapter.o
 	$(call cmd_format,WASI_LD,$@) PATH="$(FSM_SRC)/scripts:$$PATH" \
 	$(WASI_CXX) $(LD_FLAGS) $(OPENSSL_LIBS) -o $@ $^
 	$(call cmd_format,WASM_STRIP,$@) $(call WASM_STRIP,$@)
@@ -324,13 +329,13 @@ $(eval $(call compile_c,$(FSM_SRC)/fastly-world/fastly_world.c))
 # NOTE: we shadow wasm-opt by adding $(FSM_SRC)/scripts to the path, which
 # includes a script called wasm-opt that immediately exits successfully. See
 # that script for more information about why we do this.
-$(OBJ_DIR)/js-compute-runtime-component.wasm: $(FSM_OBJ) $(SM_OBJ) $(RUST_URL_LIB) $(RUST_ENCODING_LIB)
-$(OBJ_DIR)/js-compute-runtime-component.wasm: $(OBJ_DIR)/impl/main_component.o
+$(OBJ_DIR)/js-compute-runtime-component$(VARIANT).wasm: $(FSM_OBJ) $(SM_OBJ) $(RUST_URL_LIB) $(RUST_ENCODING_LIB)
+$(OBJ_DIR)/js-compute-runtime-component$(VARIANT).wasm: $(OBJ_DIR)/impl/main_component.o
 # NOTE: we don't currently link in the component type object because we
 # explicitly reference fastly.wit when building the component. If this changes,
 # uncommenting this line will link the component type object in.
-# $(OBJ_DIR)/js-compute-runtime-component.wasm: $(FSM_SRC)/fastly-world/fastly_world_component_type.o
-$(OBJ_DIR)/js-compute-runtime-component.wasm: $(OBJ_DIR)/fastly-world/fastly_world.o
+# $(OBJ_DIR)/js-compute-runtime-component$(VARIANT).wasm: $(FSM_SRC)/fastly-world/fastly_world_component_type.o
+$(OBJ_DIR)/js-compute-runtime-component$(VARIANT).wasm: $(OBJ_DIR)/fastly-world/fastly_world.o
 	$(call cmd_format,WASI_LD,$@) PATH="$(FSM_SRC)/scripts:$$PATH" \
 	$(WASI_CXX) $(LD_FLAGS) $(OPENSSL_LIBS) -o $@ $^
 	$(call cmd_format,WASM_STRIP,$@) $(call WASM_STRIP,$@)
@@ -360,12 +365,12 @@ shared/librust_encoding.a: $(RUST_ENCODING_LIB) | shared
 # Without marking them phony, the wasm won't be copied in the last invocation of
 # make, as it will look up-to-date.
 
-.PHONY: $(FSM_SRC)/js-compute-runtime.wasm
-$(FSM_SRC)/js-compute-runtime.wasm: $(OBJ_DIR)/js-compute-runtime.wasm
+.PHONY: $(FSM_SRC)/js-compute-runtime$(VARIANT).wasm
+$(FSM_SRC)/js-compute-runtime$(VARIANT).wasm: $(OBJ_DIR)/js-compute-runtime$(VARIANT).wasm
 	$(call cmd,cp,$@)
 
-.PHONY: $(FSM_SRC)/js-compute-runtime-component.wasm
-$(FSM_SRC)/js-compute-runtime-component.wasm: $(OBJ_DIR)/js-compute-runtime-component.wasm
+.PHONY: $(FSM_SRC)/js-compute-runtime-component$(VARIANT).wasm
+$(FSM_SRC)/js-compute-runtime-component$(VARIANT).wasm: $(OBJ_DIR)/js-compute-runtime-component$(VARIANT).wasm
 	$(call cmd,cp,$@)
 
 

diff --git a/runtime/spidermonkey b/runtime/spidermonkey
diff --git a/src/compileApplicationToWasm.js b/src/compileApplicationToWasm.js
@@ -4,11 +4,12 @@ import { mkdir, readFile } from "node:fs/promises";
 import { isFile } from "./isFile.js";
 import { isFileOrDoesNotExist } from "./isFileOrDoesNotExist.js";
 import wizer from "@bytecodealliance/wizer";
+import weval from "@cfallin/weval";
 import { precompile } from "./precompile.js";
 import { bundle } from "./bundle.js";
 import { containsSyntaxErrors } from "./containsSyntaxErrors.js";
 
-export async function compileApplicationToWasm(input, output, wasmEngine, enableExperimentalHighResolutionTimeMethods = false) {
+export async function compileApplicationToWasm(input, output, wasmEngine, enableExperimentalHighResolutionTimeMethods = false, enableWeval = false) {
   try {
     if (!(await isFile(input))) {
       console.error(
@@ -82,17 +83,8 @@ export async function compileApplicationToWasm(input, output, wasmEngine, enable
   let application = precompile(contents.outputFiles[0].text);
 
   try {
-    let wizerProcess = spawnSync(
-      wizer,
-      [
-        "--inherit-env=true",
-        "--allow-wasi",
-        `--dir=.`,
-        `--wasm-bulk-memory=true`,
-        "-r _start=wizer.resume",
-        `-o=${output}`,
-        wasmEngine,
-      ],
+    let wizerProcess;
+    let spawnEnv = 
       {
         stdio: [null, process.stdout, process.stderr],
         input: application,
@@ -101,8 +93,35 @@ export async function compileApplicationToWasm(input, output, wasmEngine, enable
         env: {
           ENABLE_EXPERIMENTAL_HIGH_RESOLUTION_TIME_METHODS: enableExperimentalHighResolutionTimeMethods ? '1' : '0'
         }
-      }
-    );
+      };
+    if (enableWeval) {
+      let wevalBinary = await weval();  // Lazily fetch the toolchain.
+      wizerProcess = spawnSync(
+        wevalBinary,
+        [
+          "-w",
+          "-o",
+          output,
+          "-i",
+          wasmEngine,
+        ],
+        spawnEnv
+      );
+    } else {
+      wizerProcess = spawnSync(
+        wizer,
+        [
+          "--inherit-env=true",
+          "--allow-wasi",
+          `--dir=.`,
+          `--wasm-bulk-memory=true`,
+          "-r _start=wizer.resume",
+          `-o=${output}`,
+          wasmEngine,
+        ],
+        spawnEnv
+      );
+    }
     if (wizerProcess.status !== 0) {
       throw new Error(`Wizer initialization failure`);
     }

diff --git a/src/parseInputs.js b/src/parseInputs.js
@@ -8,8 +8,10 @@ export async function parseInputs(cliInputs) {
 
   let component = false;
   let enableExperimentalHighResolutionTimeMethods = false;
+  let enableWeval = false;
   let customEngineSet = false;
-  let wasmEngine = join(__dirname, "../js-compute-runtime.wasm");
+  let wasmEngineBase = join(__dirname, "../js-compute-runtime");
+  let wasmEngine;
   let customInputSet = false;
   let input = join(process.cwd(), "bin/index.js");
   let customOutputSet = false;
@@ -25,6 +27,10 @@ export async function parseInputs(cliInputs) {
         enableExperimentalHighResolutionTimeMethods = true;
         break;
       }
+      case "--enable-weval": {
+        enableWeval = true;
+        break;
+      }
       case "-V":
       case "--version": {
         return { version: true };
@@ -35,7 +41,6 @@ export async function parseInputs(cliInputs) {
       }
       case "--component": {
         component = true;
-        wasmEngine = join(__dirname, "../js-compute-runtime-component.wasm");
         break;
       }
       case "--engine-wasm": {
@@ -93,5 +98,17 @@ export async function parseInputs(cliInputs) {
       }
     }
   }
-  return { wasmEngine, component, input, output, enableExperimentalHighResolutionTimeMethods };
+
+  if (!wasmEngine) {
+    wasmEngine = wasmEngineBase;
+    if (component) {
+      wasmEngine += "-component";
+    }
+    if (enableWeval) {
+      wasmEngine += "-weval.wasm";
+    } else {
+      wasmEngine += "-normal.wasm";
+    }
+  }
+  return { wasmEngine, component, input, output, enableExperimentalHighResolutionTimeMethods, enableWeval };
 }
diff --git a/tests/wpt-harness/run-wpt.sh b/tests/wpt-harness/run-wpt.sh
@@ -42,7 +42,7 @@ if ! npm run build > "$output" 2>&1; then
   cat "$output"
   exit 1
 fi
-cp js-compute-runtime.wasm "$working_dir"
+cp js-compute-runtime-normal.wasm "$working_dir"/js-compute-runtime.wasm
 
 cd "$working_dir"
+12 −5		.github/workflows/main.yml
+30 −19		build-engine.sh
+3 −6		download-engine.sh
+1 −1		gecko-repository
+1 −1		gecko-revision
+13 −0		mozconfig.defaults
+3 −0		mozconfig.weval
+22 −19		rebuild.sh