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 +1,34 @@
+{
+  "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"
+  }
+}

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

@@ -0,0 +1,78 @@
+import { traverse, callInstruction, numberLiteral } from "@webassemblyjs/ast";
+import i32_extend8_s from "./polyfills/i32_extend8_s.json";
+import i32_extend16_s from "./polyfills/i32_extend16_s.json";
+import i64_extend8_s from "./polyfills/i64_extend8_s.json";
+import i64_extend16_s from "./polyfills/i64_extend16_s.json";
+import i64_extend32_s from "./polyfills/i64_extend32_s.json";
+
+class Polyfills {
+  constructor(startIndex) {
+    this.startIndex = startIndex;
+
+    this.asts = {
+      i32_extend8_s,
+      i32_extend16_s,
+      i64_extend8_s,
+      i64_extend16_s,
+      i64_extend32_s
+    };
+
+    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.json

@@ -0,0 +1,165 @@
+{
+  "type": "Func",
+  "name": {
+    "type": "Identifier",
+    "value": "packages/proposal-sign-extension-ops/src/polyfills/i32_extend16_s/i32_extend16_s"
+  },
+  "signature": {
+    "type": "Signature",
+    "params": [
+      {
+        "valtype": "i32"
+      }
+    ],
+    "results": [
+      "i32"
+    ]
+  },
+  "body": [
+    {
+      "type": "Instr",
+      "id": "get_local",
+      "args": [
+        {
+          "type": "NumberLiteral",
+          "value": 0,
+          "raw": "0"
+        }
+      ],
+      "loc": {
+        "start": {
+          "line": -1,
+          "column": 59
+        },
+        "end": {
+          "line": -1,
+          "column": 61
+        }
+      }
+    },
+    {
+      "type": "Instr",
+      "id": "const",
+      "args": [
+        {
+          "type": "NumberLiteral",
+          "value": -32768,
+          "raw": "-32768"
+        }
+      ],
+      "object": "i32"
+    },
+    {
+      "type": "Instr",
+      "id": "or",
+      "args": [],
+      "object": "i32"
+    },
+    {
+      "type": "Instr",
+      "id": "get_local",
+      "args": [
+        {
+          "type": "NumberLiteral",
+          "value": 0,
+          "raw": "0"
+        }
+      ],
+      "loc": {
+        "start": {
+          "line": -1,
+          "column": 66
+        },
+        "end": {
+          "line": -1,
+          "column": 68
+        }
+      }
+    },
+    {
+      "type": "Instr",
+      "id": "const",
+      "args": [
+        {
+          "type": "NumberLiteral",
+          "value": 32767,
+          "raw": "32767"
+        }
+      ],
+      "object": "i32"
+    },
+    {
+      "type": "Instr",
+      "id": "and",
+      "args": [],
+      "object": "i32"
+    },
+    {
+      "type": "Instr",
+      "id": "get_local",
+      "args": [
+        {
+          "type": "NumberLiteral",
+          "value": 0,
+          "raw": "0"
+        }
+      ],
+      "loc": {
+        "start": {
+          "line": -1,
+          "column": 73
+        },
+        "end": {
+          "line": -1,
+          "column": 75
+        }
+      }
+    },
+    {
+      "type": "Instr",
+      "id": "const",
+      "args": [
+        {
+          "type": "NumberLiteral",
+          "value": 32768,
+          "raw": "32768"
+        }
+      ],
+      "object": "i32"
+    },
+    {
+      "type": "Instr",
+      "id": "and",
+      "args": [],
+      "object": "i32"
+    },
+    {
+      "type": "Instr",
+      "id": "select",
+      "args": [],
+      "loc": {
+        "start": {
+          "line": -1,
+          "column": 80
+        },
+        "end": {
+          "line": -1,
+          "column": 81
+        }
+      }
+    }
+  ],
+  "loc": {
+    "start": {
+      "line": -1,
+      "column": 57
+    },
+    "end": {
+      "line": -1,
+      "column": 82
+    }
+  },
+  "metadata": {
+    "bodySize": 24
+  }
+}

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

@@ -0,0 +1,6 @@
+/**
+ * Polyfill for i32_extend16_s instruction
+ */
+export function i32_extend16_s(x: i32): i32 {
+	return (x & 0x00008000) ? (x | 0xffff8000) : (x & 0x00007fff);
+}