feat: remove type section from disassembly

BREAKING CHANGE: Disassembly output will no longer print all the
types in the beginning by default.

The type section can be reconstructed from the implicit type
information in the remainder of the disassembly, and is generally
just cognitive overhead for developers, especially in the browser
DevTools (see https://crbug.com/1092763 for relevant downstream
issue in Chromium DevTools). Relying on the implicit type information
is far more readable for humans and also avoids the need to dump all
the types in the beginning, which take up precious space since both
Chromium and Firefox DevTools limit the number of lines that are
displayed for large Wasm modules.

This adds a `skipTypes` option to `WasmDisassembler` instances, which
can be used to restore the old behavior. By default this option is set
to `true`.

This includes a fix to `call_indirect` and `return_call_indirect`,
where we had previously refered to the type by name, and now we
use the abbreviated form for printing types as well [1].

[1]: https://webassembly.github.io/spec/core/text/modules.html#abbreviations

Refs: #56

src/WasmDis.spec.ts

@@ -302,7 +302,6 @@ describe("WasmDisassembler.getResult() with function code", () => {
   const fileName = `test.wat`;
   const expectedLines = [
     "(module",
-    "  (type $type0 (func (result i32)))",
     "  (export \"export.function\" (func $func0))",
     "  (func $func0 (result i32)",
     "    (local $var0 i32)",
@@ -327,7 +326,7 @@ describe("WasmDisassembler.getResult() with function code", () => {
     const result = dis.getResult();
     expect(result.done).toBe(true);
     expect(result.lines).toEqual(expectedLines);
-    expect(result.offsets).toEqual([0, 10, 22, 43, 43, 48, 50, 51, 53, 55, 83]);
+    expect(result.offsets).toEqual([0, 22, 43, 43, 48, 50, 51, 53, 55, 83]);
     expect(result.functionBodyOffsets).toEqual(
       [
         {
@@ -366,6 +365,12 @@ describe("WasmDisassembler.getResult() without function code", () => {
    (export "export.function" (func 0)))`;
   const fileName = `test.wat`;
   const expectedLines = [
+    "(module",
+    "  (import \"import\" \"function\" (func $import0))",
+    "  (export \"export.function\" (func $import0))",
+    ")",
+  ];
+  const expectedLinesWithTypes = [
     "(module",
     "  (type $type0 (func))",
     "  (import \"import\" \"function\" (func $import0))",
@@ -386,7 +391,7 @@ describe("WasmDisassembler.getResult() without function code", () => {
     const result = dis.getResult();
     expect(result.done).toBe(true);
     expect(result.lines).toEqual(expectedLines);
-    expect(result.offsets).toEqual([0, 10, 16, 37, 68, ]);
+    expect(result.offsets).toEqual([0, 16, 37, 68, ]);
     expect(result.functionBodyOffsets).toEqual([]);
   });
 
@@ -406,4 +411,18 @@ describe("WasmDisassembler.getResult() without function code", () => {
     expect(result.offsets).toBeUndefined();
     expect(result.functionBodyOffsets).toBeUndefined();
   });
+
+  test("skipTypes is false", () => {
+    const { buffer } = parseWat(fileName, watString).toBinary({
+      write_debug_names: true
+    });
+    const parser = new BinaryReader();
+    parser.setData(buffer.buffer, 0, buffer.byteLength);
+    const dis = new WasmDisassembler();
+    dis.skipTypes = false;
+    dis.disassembleChunk(parser);
+    const result = dis.getResult();
+    expect(result.done).toBe(true);
+    expect(result.lines).toEqual(expectedLinesWithTypes);
+  });
 });

src/WasmDis.ts

@@ -374,7 +374,7 @@ export class WasmDisassembler {
   private _indent: string;
   private _indentLevel: number;
   private _addOffsets: boolean;
-  private _nextLineToAddOffset: number;
+  private _skipTypes: boolean = true;
   private _done: boolean;
   private _currentPosition: number;
   private _nameResolver: INameResolver;
@@ -421,6 +421,14 @@ export class WasmDisassembler {
       throw new Error('Cannot switch addOffsets during processing.');
     this._addOffsets = value;
   }
+  public get skipTypes() {
+    return this._skipTypes;
+  }
+  public set skipTypes(skipTypes: boolean) {
+    if (this._currentPosition)
+      throw new Error('Cannot switch skipTypes during processing.');
+    this._skipTypes = skipTypes;
+  }
   public get labelMode() {
     return this._labelMode;
   }
@@ -581,8 +589,7 @@ export class WasmDisassembler {
         break;
       case OperatorCode.call_indirect:
       case OperatorCode.return_call_indirect:
-        var typeName = this._nameResolver.getTypeName(operator.typeIndex, true);
-        this.appendBuffer(` (type ${typeName})`);
+        this.printFuncType(operator.typeIndex);
         break;
       case OperatorCode.local_get:
       case OperatorCode.local_set:
@@ -1016,11 +1023,13 @@ export class WasmDisassembler {
           var funcType = <IFunctionType>reader.result;
           var typeIndex = this._types.length;
           this._types.push(funcType);
-          var typeName = this._nameResolver.getTypeName(typeIndex, false);
-          this.appendBuffer(`  (type ${typeName} (func`);
-          this.printFuncType(typeIndex);
-          this.appendBuffer('))');
-          this.newLine();
+          if (!this._skipTypes) {
+            var typeName = this._nameResolver.getTypeName(typeIndex, false);
+            this.appendBuffer(`  (type ${typeName} (func`);
+            this.printFuncType(typeIndex);
+            this.appendBuffer('))');
+            this.newLine();
+          }
           break;
         case BinaryReaderState.START_SECTION_ENTRY:
           var startEntry = <IStartEntry>reader.result;

test/address.wast.0.wasm.out

@@ -1,5 +1,4 @@
 (module
-  (type $type0 (func (param i32)))
   (import "spectest" "print" (func $import0 (param i32)))
   (memory $memory0 1)
   (export "good" (func $func1))

test/atomic.0.wasm.out

@@ -1,13 +1,4 @@
 (module
-  (type $type0 (func (param i64)))
-  (type $type1 (func (param i32) (result i32)))
-  (type $type2 (func (param i32) (result i64)))
-  (type $type3 (func (param i32 i32)))
-  (type $type4 (func (param i32 i64)))
-  (type $type5 (func (param i32 i32) (result i32)))
-  (type $type6 (func (param i32 i64) (result i64)))
-  (type $type7 (func (param i32 i32 i32) (result i32)))
-  (type $type8 (func (param i32 i64 i64) (result i64)))
   (memory $memory0 1 1 shared)
   (export "init" (func $func0))
   (export "i32.atomic.load" (func $func1))

test/atomic.1.wasm.out

@@ -1,8 +1,4 @@
 (module
-  (type $type0 (func (param i64)))
-  (type $type1 (func (param i32 i32) (result i32)))
-  (type $type2 (func (param i32 i64 i64) (result i32)))
-  (type $type3 (func (param i32 i32 i64) (result i32)))
   (memory $memory0 1 1 shared)
   (export "init" (func $func0))
   (export "atomic.notify" (func $func1))

test/block-typed.wasm.out

@@ -1,7 +1,4 @@
 (module
-  (type $type0 (func (result i32)))
-  (type $type1 (func (param i32 i32) (result i32)))
-  (type $type2 (func (param i32) (result i32)))
   (export "run" (func $func0))
   (func $func0 (result i32)
     (local $var0 i32)

test/block.wast.0.wasm.out

@@ -1,6 +1,4 @@
 (module
-  (type $type0 (func))
-  (type $type1 (func (result i32)))
   (export "empty" (func $func1))
   (export "singular" (func $func2))
   (export "multi" (func $func3))

test/br.wast.0.wasm.out

@@ -1,12 +1,4 @@
 (module
-  (type $type0 (func))
-  (type $type1 (func (result i32)))
-  (type $type2 (func (result i64)))
-  (type $type3 (func (result f32)))
-  (type $type4 (func (result f64)))
-  (type $type5 (func (param i32 i32) (result i32)))
-  (type $type6 (func (param i32 i32 i32) (result i32)))
-  (type $type7 (func (param i32 i32 i32) (result i32)))
   (table $table0 1 1 anyfunc)
   (memory $memory0 1)
   (export "type-i32" (func $func1))
@@ -343,7 +335,7 @@
       i32.const 1
       i32.const 2
       i32.const 3
-      call_indirect (type $type7)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func35 (result i32)
@@ -353,7 +345,7 @@
       br $label0
       i32.const 2
       i32.const 3
-      call_indirect (type $type7)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func36 (result i32)
@@ -363,7 +355,7 @@
       i32.const 22
       br $label0
       i32.const 3
-      call_indirect (type $type7)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func37 (result i32)
@@ -373,7 +365,7 @@
       i32.const 2
       i32.const 23
       br $label0
-      call_indirect (type $type7)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func38 (result i32)

test/br_if.wast.0.wasm.out

@@ -1,8 +1,4 @@
 (module
-  (type $type0 (func))
-  (type $type1 (func (param i32) (result i32)))
-  (type $type2 (func (param i32)))
-  (type $type3 (func (param i32 i32)))
   (export "as-block-first" (func $func1))
   (export "as-block-mid" (func $func2))
   (export "as-block-last" (func $func3))

test/br_table.wast.0.wasm.out

@@ -1,13 +1,4 @@
 (module
-  (type $type0 (func))
-  (type $type1 (func (result i32)))
-  (type $type2 (func (result i64)))
-  (type $type3 (func (result f32)))
-  (type $type4 (func (result f64)))
-  (type $type5 (func (param i32) (result i32)))
-  (type $type6 (func (param i32 i32) (result i32)))
-  (type $type7 (func (param i32 i32 i32) (result i32)))
-  (type $type8 (func (param i32 i32 i32) (result i32)))
   (table $table0 1 1 anyfunc)
   (memory $memory0 1)
   (export "type-i32" (func $func1))
@@ -504,7 +495,7 @@
       i32.const 1
       i32.const 2
       i32.const 3
-      call_indirect (type $type8)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func42 (result i32)
@@ -515,7 +506,7 @@
       br_table $label0
       i32.const 2
       i32.const 3
-      call_indirect (type $type8)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func43 (result i32)
@@ -526,7 +517,7 @@
       i32.const 1
       br_table $label0
       i32.const 3
-      call_indirect (type $type8)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func44 (result i32)
@@ -537,7 +528,7 @@
       i32.const 23
       i32.const 1
       br_table $label0
-      call_indirect (type $type8)
+      call_indirect (param i32 i32 i32) (result i32)
     end $label0
   )
   (func $func45 (result i32)

test/break-drop.wast.0.wasm.out

@@ -1,5 +1,4 @@
 (module
-  (type $type0 (func))
   (export "br" (func $func0))
   (export "br_if" (func $func1))
   (export "br_table" (func $func2))

test/call.wast.0.wasm.out

@@ -1,19 +1,4 @@
 (module
-  (type $type0 (func (result i32)))
-  (type $type1 (func (result i64)))
-  (type $type2 (func (result f32)))
-  (type $type3 (func (result f64)))
-  (type $type4 (func (param i32) (result i32)))
-  (type $type5 (func (param i64) (result i64)))
-  (type $type6 (func (param f32) (result f32)))
-  (type $type7 (func (param f64) (result f64)))
-  (type $type8 (func (param f32 i32) (result i32)))
-  (type $type9 (func (param i32 i64) (result i64)))
-  (type $type10 (func (param f64 f32) (result f32)))
-  (type $type11 (func (param i64 f64) (result f64)))
-  (type $type12 (func (param i64 i64) (result i64)))
-  (type $type13 (func (param i64) (result i32)))
-  (type $type14 (func))
   (export "type-i32" (func $func12))
   (export "type-i64" (func $func13))
   (export "type-f32" (func $func14))