[Wasm] Convert many of the fixed-size values to LEB128.

test/unittests/wasm/encoder-unittest.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "test/unittests/test-utils.h"
 
 #include "src/v8.h"
 
 #include "src/wasm/ast-decoder.h"
 #include "src/wasm/encoder.h"
@@ skipping 90 matching lines @@
 
   WasmFunctionEncoder* f = function->Build(&zone, builder);
   ZoneVector<uint8_t> buffer_vector(f->HeaderSize() + f->BodySize(), &zone);
   byte* buffer = &buffer_vector[0];
   byte* header = buffer;
   byte* body = buffer + f->HeaderSize();
   f->Serialize(buffer, &header, &body);
   body = buffer + f->HeaderSize();
 }
 
+TEST_F(EncoderTest, Function_Builder_Block_Variable_Width) {
+  Zone zone;
+  WasmModuleBuilder* builder = new (&zone) WasmModuleBuilder(&zone);
+  uint16_t f_index = builder->AddFunction();
+  WasmFunctionBuilder* function = builder->FunctionAt(f_index);
+  function->EmitWithVarInt(kExprBlock, 200);
+  for (int i = 0; i < 200; ++i) {
+    function->Emit(kExprNop);
+  }
+
+  WasmFunctionEncoder* f = function->Build(&zone, builder);
+  CHECK_EQ(f->BodySize(), 204);
+}
+
+TEST_F(EncoderTest, Function_Builder_EmitEditableVarIntImmediate) {
+  Zone zone;
+  WasmModuleBuilder* builder = new (&zone) WasmModuleBuilder(&zone);
+  uint16_t f_index = builder->AddFunction();
+  WasmFunctionBuilder* function = builder->FunctionAt(f_index);
+  function->Emit(kExprLoop);
+  uint32_t offset = function->EmitEditableVarIntImmediate();
+  for (int i = 0; i < 200; ++i) {
+    function->Emit(kExprNop);
+  }
+  function->EditVarIntImmediate(offset, 200);
+
+  WasmFunctionEncoder* f = function->Build(&zone, builder);
+  CHECK_EQ(f->BodySize(), 204);
+}
+
+TEST_F(EncoderTest, Function_Builder_EmitEditableVarIntImmediate_Locals) {
+  Zone zone;
+  WasmModuleBuilder* builder = new (&zone) WasmModuleBuilder(&zone);
+  uint16_t f_index = builder->AddFunction();
+  WasmFunctionBuilder* function = builder->FunctionAt(f_index);
+  function->Emit(kExprBlock);
+  uint32_t offset = function->EmitEditableVarIntImmediate();
+  for (int i = 0; i < 200; ++i) {
+    AddLocal(function, kAstI32);
+  }
+  function->EditVarIntImmediate(offset, 200);
+
+  WasmFunctionEncoder* f = function->Build(&zone, builder);
+  ZoneVector<uint8_t> buffer_vector(f->HeaderSize() + f->BodySize(), &zone);
+  byte* buffer = &buffer_vector[0];
+  byte* header = buffer;
+  byte* body = buffer + f->HeaderSize();
+  f->Serialize(buffer, &header, &body);
+  body = buffer + f->HeaderSize();
+
+  CHECK_EQ(f->BodySize(), 479);
+  const uint8_t varint200_low = (200 & 0x7f) | 0x80;
+  const uint8_t varint200_high = (200 >> 7) & 0x7f;
+  offset = 0;
+  CHECK_EQ(body[offset++], 1);  // Local decl count.
+  CHECK_EQ(body[offset++], varint200_low);
+  CHECK_EQ(body[offset++], varint200_high);
+  CHECK_EQ(body[offset++], kLocalI32);
+  CHECK_EQ(body[offset++], kExprBlock);
+  CHECK_EQ(body[offset++], varint200_low);
+  CHECK_EQ(body[offset++], varint200_high);
+  // GetLocal with one-byte indices.
+  for (int i = 0; i <= 127; ++i) {
+    CHECK_EQ(body[offset++], kExprGetLocal);
+    CHECK_EQ(body[offset++], i);
+  }
+  // GetLocal with two-byte indices.
+  for (int i = 128; i < 200; ++i) {
+    CHECK_EQ(body[offset++], kExprGetLocal);
+    CHECK_EQ(body[offset++], (i & 0x7f) | 0x80);
+    CHECK_EQ(body[offset++], (i >> 7) & 0x7f);
+  }
+  CHECK_EQ(offset, 479);
+}
 
 TEST_F(EncoderTest, LEB_Functions) {
   byte leb_value[5] = {0, 0, 0, 0, 0};
   CheckReadValue(leb_value, 0, 1, kNoError);
   CheckWriteValue(0, 1, leb_value);
   leb_value[0] = 23;
   CheckReadValue(leb_value, 23, 1, kNoError);
   CheckWriteValue(23, 1, leb_value);
   leb_value[0] = 0x80;
   leb_value[1] = 0x01;
   CheckReadValue(leb_value, 128, 2, kNoError);
   CheckWriteValue(128, 2, leb_value);
   leb_value[0] = 0x80;
   leb_value[1] = 0x80;
   leb_value[2] = 0x80;
   leb_value[3] = 0x80;
   leb_value[4] = 0x01;
   CheckReadValue(leb_value, 0x10000000, 5, kNoError);
   CheckWriteValue(0x10000000, 5, leb_value);
   leb_value[0] = 0x80;
   leb_value[1] = 0x80;
   leb_value[2] = 0x80;
   leb_value[3] = 0x80;
   leb_value[4] = 0x80;
   CheckReadValue(leb_value, -1, -1, kInvalidLEB128);
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8