Implement .table and .elem

asm.js

@@ -100,6 +100,10 @@ const State = Object.freeze({
     TYPE_NAME:    28,
     TYPE_PARAM:   29,
     TYPE_RESULT:  30,
+    TABLE_NAME:   31,
+    TABLE_SIZE:   32,
+    ELEM_TABLE:   33,
+    ELEM_ELEM:    34,
 });
 
 const Action = Object.freeze({
@@ -122,6 +126,8 @@ const Action = Object.freeze({
     EXIT:   17,
     ELSE:   18,
     TYPE:   19,
+    TABLE:  20,
+    ELEM:   21,
 });
 
 const types = {
@@ -214,6 +220,8 @@ class Parser {
             ".align":  State.ALIGN,
             ".def":    State.DEF_NAME,
             ".type":   State.TYPE_NAME,
+            ".table":  State.TABLE_NAME,
+            ".elem":   State.ELEM_TABLE,
         };
         this.blocks = new Set(["block", "loop", "if"]);
         this.handlers = {
@@ -248,6 +256,10 @@ class Parser {
             [State.TYPE_NAME]:    (token) => this.token_type_name(token),
             [State.TYPE_PARAM]:   (token) => this.token_type_param(token),
             [State.TYPE_RESULT]:  (token) => this.token_type_result(token),
+            [State.TABLE_NAME]:   (token) => this.token_table_name(token),
+            [State.TABLE_SIZE]:   (token) => this.token_table_size(token),
+            [State.ELEM_TABLE]:   (token) => this.token_elem_table(token),
+            [State.ELEM_ELEM]:    (token) => this.token_elem_elem(token),
         };
 
         this.results = [];
@@ -740,6 +752,73 @@ class Parser {
         this.type.results.push(type);
     }
 
+    token_table_name(token) {
+        if (token == LINE_END) {
+            console.error(
+                "ERROR: Unexpected end of line in .table, expected name");
+            this.state = State.TOP;
+            return;
+        }
+
+        this.table = { name: token };
+        this.state = State.TABLE_SIZE;
+    }
+
+    token_table_size(token) {
+        if (token == LINE_END) {
+            console.error(
+                "ERROR: Unexpected end of line in .table, expected size");
+            this.table = undefined;
+            this.state = State.TOP;
+            return;
+        }
+
+        const size = this.integer(token);
+        if (size == null) {
+            console.error(
+                `ERROR: Unexpected token ${token} in .table, expected size`);
+            this.table = undefined;
+            this.state = State.TOP;
+            return;
+        }
+
+        this.table.size = size;
+        const action = { type: Action.TABLE, table: this.table };
+        this.table = undefined;
+        this.state = State.TOP;
+        return action;
+    }
+
+    token_elem_table(token) {
+        if (token == LINE_END) {
+            console.error(
+                "ERROR: Unexpected end of line in .elem, expected "
+                    + "table name");
+            this.state = State.TOP;
+            return;
+        }
+
+        this.elem = { table: token };
+        this.state = State.ELEM_ELEM;
+    }
+
+    token_elem_elem(token) {
+        if (token == LINE_END) {
+            console.error(
+                "ERROR: Unexpected end of line in .elem, expected "
+                    + "element name");
+            this.state = State.TOP;
+            this.elem = undefined;
+            return;
+        }
+
+        this.elem.elem = token;
+        const action = { type: Action.ELEM, elem: this.elem };
+        this.elem = undefined
+        this.state = State.TOP;
+        return action;
+    }
+
     mem_action() {
         const action = {
             type: Action.MEM,
@@ -771,9 +850,11 @@ const Section = Object.freeze({
     TYPE:   0x01,
     IMPORT: 0x02,
     FUNC:   0x03,
+    TABLE:  0x04,
     MEM:    0x05,
     GLOBAL: 0x06,
     EXPORT: 0x07,
+    ELEM:   0x09,
     CODE:   0x0a,
     DATA:   0x0b,
 });
@@ -808,6 +889,8 @@ export class Assembler {
             [Action.EXIT]:   (action) => this.action_exit(action),
             [Action.ELSE]:   (action) => this.action_else(action),
             [Action.TYPE]:   (action) => this.action_type(action),
+            [Action.TABLE]:  (action) => this.action_table(action),
+            [Action.ELEM]:   (action) => this.action_elem(action),
         };
 
         this.exports = [];
@@ -821,6 +904,7 @@ export class Assembler {
         this.blocks = [];
         this.types = [];
         this.type_bindings = {};
+        this.tables = {};
 	}
 
     action_append(action) {
@@ -959,6 +1043,23 @@ export class Assembler {
         this.type_bindings[action.the_type.name] = index;
     }
 
+    action_table(action) {
+        this.tables[action.table.name] = {
+            size: action.table.size,
+            elems: [],
+        };
+    }
+
+    action_elem(action) {
+        const table = this.tables[action.elem.table];
+        const index = Object.keys(this.funcs).indexOf(action.elem.elem);
+        if (index == -1) {
+            console.error(`ERROR: ${action.elem.elem}: no such function`);
+            return;
+        }
+        table.elems.push(index);
+    }
+
 	push(chunk) {
 		const text = this.decoder.decode(chunk, { stream: true });
 		for (const action of this.parser.handle(text)) {
@@ -1009,7 +1110,6 @@ export class Assembler {
     }
 
     leb128(x) {
-        const orig = x;
         const bytes = [];
         while (true) {
             const b = x & 0x7f;
@@ -1022,6 +1122,18 @@ export class Assembler {
         }
     }
 
+    uleb128(x) {
+        const bytes = [];
+        do {
+            const b = x & 0x7f;
+            x >>= 7;
+            if (x != 0)
+                b |= 0x80;
+            bytes.push(b);
+        } while (x != 0);
+        return bytes;
+    }
+
     wasm_section_type() {
         if (this.types.length == 0) return null;
         return [ this.types.length ].concat(...this.types);
@@ -1052,6 +1164,17 @@ export class Assembler {
         return [ count, ...types ];
     }
 
+    wasm_section_table() {
+        const sizes = Object.values(this.tables).map(({size}) => size);
+        if (sizes.length == 0) return null;
+        const contents = sizes.map((size) => [
+            types.funcref,
+            0x00,
+            this.uleb128(size),
+        ]);
+        return [ sizes.length, contents ].flat(Infinity)
+    }
+
     wasm_section_mem() {
         const mems = Object.values(this.mems).filter(
             ({imported}) => !imported);
@@ -1085,6 +1208,24 @@ export class Assembler {
         return [ exports.length ].concat(...contents);
     }
 
+    wasm_section_elem() {
+        const table_elems = Object.values(this.tables).map(
+            ({elems}) => elems);
+        const count = table_elems.flat().length;
+        if (count == 0) return null;
+        const contents = table_elems.flatMap((elems, table) =>
+            elems.flatMap((fn, index) => [
+                table == 0 ? 0 : [ 2, table ],
+                opcodes["i32.const"],
+                index,
+                opcodes["end"],
+                1,
+                fn,
+            ])
+        );
+        return [ count, contents ].flat();
+    }
+
     wasm_section_code() {
         const funcs = Object.values(this.funcs);
         if (funcs.length == 0) return null;
@@ -1134,9 +1275,11 @@ export class Assembler {
             [ Section.TYPE,   () => this.wasm_section_type() ],
             [ Section.IMPORT, () => this.wasm_section_import() ],
             [ Section.FUNC,   () => this.wasm_section_func() ],
+            [ Section.TABLE,  () => this.wasm_section_table() ],
             [ Section.MEM,    () => this.wasm_section_mem() ],
             [ Section.GLOBAL, () => this.wasm_section_global() ],
             [ Section.EXPORT, () => this.wasm_section_export() ],
+            [ Section.ELEM,   () => this.wasm_section_elem() ],
             [ Section.CODE,   () => this.wasm_section_code() ],
             [ Section.DATA,   () => this.wasm_section_data() ],
         ];