WIP: Transpile sign extension proposal

.gitignore

@@ -60,3 +60,6 @@ typings/
 lib/
 
 package-lock.json
+
+# Generated polyfill binaries
+packages/proposal-sign-extension-ops/src/polyfills/*.wasm

package.json

@@ -31,7 +31,8 @@
     "markdown-to-html": "0.0.13",
     "mocha": "4.0.1",
     "performance-now": "2.1.0",
-    "prettier": "1.9.2"
+    "prettier": "1.9.2",
+	"assemblyscript": "github:AssemblyScript/assemblyscript"
   },
   "dependencies": {
     "babel-plugin-mamacro": "0.0.3",

packages/helper-wasm-bytecode/src/index.js

@@ -319,6 +319,13 @@ const symbolsByByte = {
   0xba: createSymbolObject("convert_u/i64", "f64"),
   0xbb: createSymbolObject("promote/f32", "f64"),
 
+  // Sign extension op proposal
+  0xc0: createSymbolObject("extend8_s", "i32"),
+  0xc1: createSymbolObject("extend16_s", "i32"),
+  0xc2: createSymbolObject("extend8_s", "i64"),
+  0xc3: createSymbolObject("extend16_s", "i64"),
+  0xc4: createSymbolObject("extend32_s", "i64"),
+
   0xbc: createSymbolObject("reinterpret/f32", "i32"),
   0xbd: createSymbolObject("reinterpret/f64", "i64"),
   0xbe: createSymbolObject("reinterpret/i32", "f32"),

packages/proposal-sign-extension-ops/README.md

@@ -0,0 +1,4 @@
+# Sign extension proposal
+
+<https://github.com/WebAssembly/sign-extension-ops>
+

packages/proposal-sign-extension-ops/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "@webassemblyjs/proposal-sign-ops",
+  "version": "1.5.6",
+  "description": "",
+  "main": "lib/index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/xtuc/webassemblyjs.git"
+  },
+  "publishConfig": {
+    "access": "public"
+  },
+  "author": "Mauro Bringolf",
+  "license": "MIT",
+  "dependencies": {
+    "@webassemblyjs/ast": "1.5.6",
+    "@webassemblyjs/helper-buffer": "1.5.6",
+    "@webassemblyjs/helper-wasm-bytecode": "1.5.6",
+    "@webassemblyjs/helper-wasm-section": "1.5.6",
+    "@webassemblyjs/wasm-edit": "1.5.6",
+    "@webassemblyjs/wasm-gen": "1.5.6",
+    "@webassemblyjs/wasm-opt": "1.5.6",
+    "debug": "^3.1.0"
+  },
+  "devDependencies": {
+    "@webassemblyjs/helper-test-framework": "1.5.6",
+    "@webassemblyjs/wast-parser": "1.5.6",
+    "@webassemblyjs/wasm-parser": "1.5.6",
+    "@webassemblyjs/wast-printer": "1.5.6",
+    "wabt": "1.0.0"
+  }
+}

packages/proposal-sign-extension-ops/src/index.js

@@ -0,0 +1,91 @@
+import { traverse, callInstruction, numberLiteral } from "@webassemblyjs/ast";
+import { parse } from "@webassemblyjs/wast-parser";
+import { readFileSync } from "fs";
+import path from "path";
+
+const funcFromWast = sourcePath => {
+  const ast = parse(readFileSync(sourcePath, "utf8"));
+  return ast.body[0].fields.find(f => f.type === "Func");
+};
+
+class Polyfills {
+  constructor(startIndex) {
+    this.startIndex = startIndex;
+
+    this.asts = {
+      i32_extend8_s: funcFromWast(
+        path.join(__dirname, "/polyfills/i32_extend8_s.wast")
+      ),
+      i32_extend16_s: funcFromWast(
+        path.join(__dirname, "/polyfills/i32_extend16_s.wast")
+      ),
+      i64_extend8_s: funcFromWast(
+        path.join(__dirname, "/polyfills/i64_extend8_s.wast")
+      ),
+      i64_extend16_s: funcFromWast(
+        path.join(__dirname, "/polyfills/i64_extend16_s.wast")
+      ),
+      i64_extend32_s: funcFromWast(
+        path.join(__dirname, "/polyfills/i64_extend32_s.wast")
+      )
+    };
+
+    this.instructions = Object.keys(this.asts);
+
+    this.index = {};
+
+    this.instructions.forEach(instrName => {
+      this.index[instrName] = -1;
+    });
+  }
+
+  replaceWith(path, instrName) {
+    if (this.index[instrName] === -1) {
+      this.index[instrName] = this.startIndex++;
+    }
+
+    const index = this.index[instrName];
+    path.replaceWith(callInstruction(numberLiteral(index, String(index))));
+  }
+
+  matchesInstruction(instrName) {
+    return this.instructions.includes(instrName);
+  }
+
+  insertInto(ast) {
+    const funcsToPush = Object.keys(this.index)
+      .filter(instrName => this.index[instrName] >= 0)
+      .sort((x, y) => (this.index[x] > this.index[y] ? 1 : -1))
+      .map(instrName => this.asts[instrName]);
+
+    ast.body[0].fields.push(...funcsToPush);
+  }
+}
+
+export function transformAst(ast) {
+  let numberOfFuncs = 0;
+
+  const countFuncVisitor = {
+    Func() {
+      ++numberOfFuncs;
+    }
+  };
+
+  traverse(ast, countFuncVisitor);
+
+  const polyfills = new Polyfills(numberOfFuncs);
+
+  const signExtendVisitor = {
+    Instr(path) {
+      if (polyfills.matchesInstruction(path.node.id)) {
+        polyfills.replaceWith(path, path.node.id);
+      }
+    }
+  };
+
+  traverse(ast, signExtendVisitor);
+
+  polyfills.insertInto(ast);
+
+  return ast;
+}

packages/proposal-sign-extension-ops/src/polyfills/i32_extend16_s.wast

@@ -0,0 +1,16 @@
+(module
+  (type (func (param i32) (result i32)))
+  (func $i32_extend16_s (param i32) (result i32)
+    (get_local 0)
+    (i32.const -32768)
+    (i32.or)
+    (get_local 0)
+    (i32.const 32767)
+    (i32.and)
+    (get_local 0)
+    (i32.const 32768)
+    (i32.and)
+    (select)
+  )
+  (export "i32_extend16_s" (func $i32_extend16_s))
+)

packages/proposal-sign-extension-ops/src/polyfills/i32_extend8_s.wast

@@ -0,0 +1,16 @@
+(module
+  (type (func (param i32) (result i32)))
+  (func $i32_extend8_s (param i32) (result i32)
+    (get_local 0)
+    (i32.const -128)
+    (i32.or)
+    (get_local 0)
+    (i32.const 127)
+    (i32.and)
+    (get_local 0)
+    (i32.const 128)
+    (i32.and)
+    (select)
+  )
+  (export "i32_extend8_s" (func $i32_extend8_s))
+)

packages/proposal-sign-extension-ops/src/polyfills/i64_extend16_s.wast

@@ -0,0 +1,18 @@
+(module
+  (type (func (param i64) (result i64)))
+  (func $i64_extend16_s (param i64) (result i64)
+    (get_local 0)
+    (i64.const -32768)
+    (i64.or)
+    (get_local 0)
+    (i64.const 32767)
+    (i64.and)
+    (get_local 0)
+    (i64.const 32768)
+    (i64.and)
+    (i64.const 0)
+    (i64.ne)
+    (select)
+  )
+  (export "i64_extend16_s" (func $i64_extend16_s))
+)

packages/proposal-sign-extension-ops/src/polyfills/i64_extend32_s.wast

@@ -0,0 +1,18 @@
+(module
+  (type (func (param i64) (result i64)))
+  (func $i64_extend32_s (param i64) (result i64)
+    (get_local 0)
+    (i64.const -2147483648)
+    (i64.or)
+    (get_local 0)
+    (i64.const 2147483647)
+    (i64.and)
+    (get_local 0)
+    (i64.const 2147483648)
+    (i64.and)
+    (i64.const 0)
+    (i64.ne)
+    (select)
+  )
+  (export "i64_extend32_s" (func $i64_extend32_s))
+)

packages/proposal-sign-extension-ops/src/polyfills/i64_extend8_s.wast

@@ -0,0 +1,18 @@
+(module
+  (type (func (param i64) (result i64)))
+  (func $i64_extend8_s (param i64) (result i64)
+    (get_local 0)
+    (i64.const -128)
+    (i64.or)
+    (get_local 0)
+    (i64.const 127)
+    (i64.and)
+    (get_local 0)
+    (i64.const 128)
+    (i64.and)
+    (i64.const 0)
+    (i64.ne)
+    (select)
+  )
+  (export "i64_extend8_s" (func $i64_extend8_s))
+)

packages/proposal-sign-extension-ops/test/exec.js

@@ -0,0 +1,54 @@
+const path = require("path");
+const wabt = require("wabt");
+const assert = require("assert");
+
+const { readFileSync } = require("fs");
+
+const polyfills = [
+  {
+    name: "i32_extend8_s",
+    fixtures: [
+      [0, 0],
+      [0x7f, 127],
+      [0x80, -128],
+      [0xff, -1],
+      [0x01234500, 0],
+      [0xfedcba80, -0x80],
+      [-1, -1]
+    ]
+  },
+  {
+    name: "i32_extend16_s",
+    fixtures: [
+      [0, 0],
+      [0x7fff, 32767],
+      [0x8000, -32768],
+      [0xffff, -1],
+      [0x01230000, 0],
+      [0xfedc8000, -0x8000],
+      [-1, -1]
+    ]
+  }
+];
+
+polyfills.forEach(p => {
+  p.path = path.join(__dirname, `../lib/polyfills/${p.name}.wast`);
+});
+
+polyfills.forEach(polyfill => {
+  describe(polyfill.path, () => {
+    const wast = readFileSync(polyfill.path, "utf8").trim();
+    const wasm = wabt
+      .parseWat(polyfill.path, wast)
+      .toBinary({ write_debug_names: false });
+
+    it("should return correct values", () => {
+      return WebAssembly.instantiate(wasm.buffer).then(result => {
+        const polyfillFn = result.instance.exports[polyfill.name];
+        polyfill.fixtures.forEach(([input, output]) => {
+          assert.equal(output, polyfillFn(input));
+        });
+      });
+    });
+  });
+});

packages/proposal-sign-extension-ops/test/index.js

@@ -0,0 +1,41 @@
+const { parse } = require("@webassemblyjs/wast-parser");
+const { print } = require("@webassemblyjs/wast-printer");
+const path = require("path");
+
+const {
+  getFixtures,
+  compareStrings
+} = require("@webassemblyjs/helper-test-framework");
+const { readFileSync, existsSync, writeFileSync } = require("fs");
+
+const { transformAst } = require("../lib/");
+
+const testCases = getFixtures(
+  path.join(__dirname, "./wast/"),
+  "/**/input.wast"
+);
+
+testCases.forEach(testCase => {
+  describe(testCase, () => {
+    const input = readFileSync(testCase, "utf8").trim();
+
+    it("should transpile sign extension operators into functions correctly", () => {
+      const actualOutput = print(transformAst(parse(input)));
+
+      if (!existsSync(path.join(path.dirname(testCase), "output.wast"))) {
+        writeFileSync(
+          path.join(path.dirname(testCase), "output.wast"),
+          actualOutput
+        );
+        return;
+      }
+
+      const expectedOutput = readFileSync(
+        path.join(path.dirname(testCase), "output.wast"),
+        "utf8"
+      ).trim();
+
+      compareStrings(actualOutput, expectedOutput);
+    });
+  });
+});

packages/proposal-sign-extension-ops/test/wast/empty/input.wast

@@ -0,0 +1,4 @@
+(module
+  (func)
+)
+

packages/proposal-sign-extension-ops/test/wast/empty/output.wast

@@ -0,0 +1,4 @@
+(module
+  (func)
+)
+

packages/proposal-sign-extension-ops/test/wast/mixed/input.wast

@@ -0,0 +1,15 @@
+(module
+  (func (param i32) (result i32)
+    (get_local 0)
+    (i32_extend16_s)
+    (i32_extend8_s)
+  )
+  (func (param i32) (result i32)
+    (get_local 0)
+  )
+  (func (param i32) (result i32)
+    (get_local 0)
+    (i32_extend8_s)
+  )
+)
+