[wasm][test] Add method to create signed LEB values

This method will be used for a test with multiple code spaces, to
encode large function indexes. The current implementation in
{wasmI32Const} just always uses 5 bytes for encoding the LEB value.
This CL adds a {wasmSignedLeb} function which properly encodes the
value, and adds tests for that.

Drive-by: Clean up the rest of {test-wasm-module-builder.js}.

R=mstarzinger@chromium.org

Bug: v8:9477
Change-Id: Ide2d90eed9d40aa28df680fbb413275346d9c0b6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1725623Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62990}

test/mjsunit/wasm/test-wasm-module-builder.js

@@ -13,12 +13,12 @@ function instantiate(buffer, ffi) {
 }
 
 (function BasicTest() {
-  print("BasicTest");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
   builder.addMemory(1, 2, false);
-    builder.addFunction("foo", kSig_i_v)
+  builder.addFunction('foo', kSig_i_v)
       .addBody([kExprI32Const, 11])
-        .exportAs("blarg");
+      .exportAs('blarg');
 
   var buffer = builder.toBuffer(debug);
   var instance = instantiate(buffer);
@@ -26,26 +26,26 @@ function instantiate(buffer, ffi) {
 })();
 
 (function ImportTest() {
-  print("ImportTest");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
-  var index = builder.addImport("", "print", makeSig_v_x(kWasmI32));
-    builder.addFunction("foo", kSig_v_v)
+  var index = builder.addImport('', 'print', makeSig_v_x(kWasmI32));
+  builder.addFunction('foo', kSig_v_v)
       .addBody([kExprI32Const, 13, kExprCallFunction, index])
-        .exportAs("main");
+      .exportAs('main');
 
   var buffer = builder.toBuffer(debug);
-    var instance = instantiate(buffer, {"": {print: print}});
-    print("should print 13! ");
+  var instance = instantiate(buffer, {'': {print: print}});
+  print('should print 13! ');
   instance.exports.main();
 })();
 
 (function LocalsTest() {
-  print("LocalsTest");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
   builder.addFunction(undefined, kSig_i_i)
       .addLocals({i32_count: 1})
       .addBody([kExprGetLocal, 0, kExprSetLocal, 1, kExprGetLocal, 1])
-        .exportAs("main");
+      .exportAs('main');
 
   var buffer = builder.toBuffer(debug);
   var instance = instantiate(buffer);
@@ -54,11 +54,11 @@ function instantiate(buffer, ffi) {
 })();
 
 (function LocalsTest2() {
-  print("LocalsTest2");
+  print(arguments.callee.name);
   // TODO(titzer): i64 only works on 64-bit platforms.
   var types = [
     {locals: {i32_count: 1}, type: kWasmI32},
-//      {locals: {i64_count: 1}, type: kWasmI64},
+    // {locals: {i64_count: 1}, type: kWasmI64},
     {locals: {f32_count: 1}, type: kWasmF32},
     {locals: {f64_count: 1}, type: kWasmF64},
   ];
@@ -68,7 +68,7 @@ function instantiate(buffer, ffi) {
     builder.addFunction(undefined, makeSig_r_x(p.type, p.type))
         .addLocals(p.locals)
         .addBody([kExprGetLocal, 0, kExprSetLocal, 1, kExprGetLocal, 1])
-        .exportAs("main");
+        .exportAs('main');
 
     var buffer = builder.toBuffer(debug);
     var instance = instantiate(buffer);
@@ -78,13 +78,14 @@ function instantiate(buffer, ffi) {
 })();
 
 (function CallTest() {
-  print("CallTest");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
-    builder.addFunction("add", kSig_i_ii)
-        .addBody([kExprGetLocal, 0, kExprGetLocal, 1, kExprI32Add]);
-    builder.addFunction("main", kSig_i_ii)
+  builder.addFunction('add', kSig_i_ii).addBody([
+    kExprGetLocal, 0, kExprGetLocal, 1, kExprI32Add
+  ]);
+  builder.addFunction('main', kSig_i_ii)
       .addBody([kExprGetLocal, 0, kExprGetLocal, 1, kExprCallFunction, 0])
-        .exportAs("main");
+      .exportAs('main');
 
   var instance = builder.instantiate();
   assertEquals(44, instance.exports.main(11, 33));
@@ -92,29 +93,32 @@ function instantiate(buffer, ffi) {
 })();
 
 (function IndirectCallTest() {
-  print("IndirectCallTest");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
-    builder.addFunction("add", kSig_i_ii)
-        .addBody([kExprGetLocal, 0, kExprGetLocal, 1, kExprI32Add]);
-    builder.addFunction("main", kSig_i_iii)
-        .addBody([kExprGetLocal,
-                  1, kExprGetLocal, 2, kExprGetLocal, 0, kExprCallIndirect, 0, kTableZero])
-        .exportAs("main");
+  builder.addFunction('add', kSig_i_ii).addBody([
+    kExprGetLocal, 0, kExprGetLocal, 1, kExprI32Add
+  ]);
+  builder.addFunction('main', kSig_i_iii)
+      .addBody([
+        kExprGetLocal, 1, kExprGetLocal, 2, kExprGetLocal, 0, kExprCallIndirect,
+        0, kTableZero
+      ])
+      .exportAs('main');
   builder.appendToTable([0]);
 
   var instance = builder.instantiate();
   assertEquals(44, instance.exports.main(0, 11, 33));
   assertEquals(7777, instance.exports.main(0, 2222, 5555));
-    assertThrows(function() { instance.exports.main(1, 1, 1); });
+  assertThrows(() => instance.exports.main(1, 1, 1));
 })();
 
 (function DataSegmentTest() {
-  print("DataSegmentTest");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
   builder.addMemory(1, 1, false);
-    builder.addFunction("load", kSig_i_i)
+  builder.addFunction('load', kSig_i_i)
       .addBody([kExprGetLocal, 0, kExprI32LoadMem, 0, 0])
-        .exportAs("load");
+      .exportAs('load');
   builder.addDataSegment(0, [9, 9, 9, 9]);
 
   var buffer = builder.toBuffer(debug);
@@ -122,14 +126,13 @@ function instantiate(buffer, ffi) {
   assertEquals(151587081, instance.exports.load(0));
 })();
 
-
 (function BasicTestWithUint8Array() {
-  print("BasicTestWithUint8Array");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
   builder.addMemory(1, 2, false);
-    builder.addFunction("foo", kSig_i_v)
+  builder.addFunction('foo', kSig_i_v)
       .addBody([kExprI32Const, 17])
-        .exportAs("blarg");
+      .exportAs('blarg');
 
   var buffer = builder.toBuffer(debug);
   var array = new Uint8Array(buffer);
@@ -151,15 +154,33 @@ function instantiate(buffer, ffi) {
 })();
 
 (function ImportTestTwoLevel() {
-  print("ImportTestTwoLevel");
+  print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
-    var index = builder.addImport("mod", "print", makeSig_v_x(kWasmI32));
-    builder.addFunction("foo", kSig_v_v)
+  var index = builder.addImport('mod', 'print', makeSig_v_x(kWasmI32));
+  builder.addFunction('foo', kSig_v_v)
       .addBody([kExprI32Const, 19, kExprCallFunction, index])
-        .exportAs("main");
+      .exportAs('main');
 
   var buffer = builder.toBuffer(debug);
   var instance = instantiate(buffer, {mod: {print: print}});
-    print("should print 19! ");
+  print('should print 19! ');
   instance.exports.main();
 })();
+
+(function TestI32Const() {
+  print(arguments.callee.name);
+  let ints = [
+    // A few negative number of different length.
+    -3 << 28, -20000, -400, -200, -100, -50, -10, -1,
+    // And a few positive number of different length.
+    0, 1, 2, 20, 120, 130, 260, 500, 5000000, 3 << 28
+  ];
+  for (let i of ints) {
+    let builder = new WasmModuleBuilder();
+    builder.addFunction('main', kSig_i_v)
+        .addBody([...wasmI32Const(i)])
+        .exportAs('main');
+    let instance = builder.instantiate();
+    assertEquals(i, instance.exports.main());
+  }
+})();

test/mjsunit/wasm/wasm-module-builder.js

@@ -552,7 +552,7 @@ class Binary {
     this.buffer[this.length++] = val >> 24;
   }
 
-  emit_leb(val, max_len) {
+  emit_leb_u(val, max_len) {
     this.ensure_space(max_len);
     for (let i = 0; i < max_len; ++i) {
       let v = val & 0xff;
@@ -567,11 +567,11 @@ class Binary {
   }
 
   emit_u32v(val) {
-    this.emit_leb(val, kMaxVarInt32Size);
+    this.emit_leb_u(val, kMaxVarInt32Size);
   }
 
   emit_u64v(val) {
-    this.emit_leb(val, kMaxVarInt64Size);
+    this.emit_leb_u(val, kMaxVarInt64Size);
   }
 
   emit_bytes(data) {
@@ -1384,13 +1384,24 @@ class WasmModuleBuilder {
   }
 }
 
-function wasmI32Const(val) {
-  let bytes = [kExprI32Const];
-  for (let i = 0; i < 4; ++i) {
-    bytes.push(0x80 | ((val >> (7 * i)) & 0x7f));
+function wasmSignedLeb(val, max_len = 5) {
+  let res = [];
+  for (let i = 0; i < max_len; ++i) {
+    let v = val & 0x7f;
+    // If {v} sign-extended from 7 to 32 bits is equal to val, we are done.
+    if (((v << 25) >> 25) == val) {
+      res.push(v);
+      return res;
+    }
+    res.push(v | 0x80);
+    val = val >> 7;
   }
-  bytes.push((val >> (7 * 4)) & 0x7f);
-  return bytes;
+  throw new Error(
+      'Leb value <' + val + '> exceeds maximum length of ' + max_len);
+}
+
+function wasmI32Const(val) {
+  return [kExprI32Const, ...wasmSignedLeb(val, 5)];
 }
 
 function wasmF32Const(f) {