[wasm] remove extra nops in asm-wasm

src/wasm/asm-wasm-builder.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 "src/v8.h"
 
 // Required to get M_E etc. in MSVC.
 #if defined(_WIN32)
 #define _USE_MATH_DEFINES
 #endif
@@ skipping 169 matching lines @@
       if (elem.first == stmt->target()) {
         DCHECK(elem.second);
         break;
       } else if (elem.second) {
         block_distance += 2;
       } else {
         block_distance += 1;
       }
     }
     DCHECK(i >= 0);
-    current_function_builder_->Emit(kExprNop);
     current_function_builder_->EmitWithU8(kExprBr, ARITY_0);
     current_function_builder_->EmitVarInt(block_distance);
   }
 
   void VisitBreakStatement(BreakStatement* stmt) {
     DCHECK_EQ(kFuncScope, scope_);
     DCHECK_NOT_NULL(stmt->target());
     int i = static_cast<int>(breakable_blocks_.size()) - 1;
     int block_distance = 0;
     for (; i >= 0; i--) {
       auto elem = breakable_blocks_.at(i);
       if (elem.first == stmt->target()) {
         if (elem.second) {
           block_distance++;
         }
         break;
       } else if (elem.second) {
         block_distance += 2;
       } else {
         block_distance += 1;
       }
     }
     DCHECK(i >= 0);
-    current_function_builder_->Emit(kExprNop);
     current_function_builder_->EmitWithU8(kExprBr, ARITY_0);
     current_function_builder_->EmitVarInt(block_distance);
   }
 
   void VisitReturnStatement(ReturnStatement* stmt) {
     if (scope_ == kModuleScope) {
       scope_ = kExportScope;
       RECURSE(Visit(stmt->expression()));
       scope_ = kModuleScope;
     } else if (scope_ == kFuncScope) {
@@ skipping 31 matching lines @@
       breakable_blocks_.push_back(std::make_pair(nullptr, false));
       HandleCase(node->right, case_to_block, tag, default_block, if_depth);
       current_function_builder_->Emit(kExprElse);
     }
     if (node->begin == node->end) {
       VisitVariableProxy(tag);
       current_function_builder_->EmitI32Const(node->begin);
       current_function_builder_->Emit(kExprI32Eq);
       current_function_builder_->Emit(kExprIf);
       DCHECK(case_to_block.find(node->begin) != case_to_block.end());
-      current_function_builder_->Emit(kExprNop);
       current_function_builder_->EmitWithU8(kExprBr, ARITY_0);
       current_function_builder_->EmitVarInt(1 + if_depth +
                                             case_to_block.at(node->begin));
       current_function_builder_->Emit(kExprEnd);
     } else {
-      current_function_builder_->Emit(kExprNop);
       if (node->begin != 0) {
         VisitVariableProxy(tag);
         current_function_builder_->EmitI32Const(node->begin);
         current_function_builder_->Emit(kExprI32Sub);
       } else {
         VisitVariableProxy(tag);
       }
       current_function_builder_->EmitWithU8(kExprBrTable, ARITY_0);
       current_function_builder_->EmitVarInt(node->end - node->begin + 1);
       for (int v = node->begin; v <= node->end; v++) {
@@ skipping 52 matching lines @@
     }
     if (!has_default || case_count > 1) {
       int default_block = has_default ? case_count - 1 : case_count;
       BlockVisitor switch_logic_block(this, nullptr, kExprBlock, false);
       CaseNode* root = OrderCases(&cases, zone_);
       HandleCase(root, case_to_block, tag, default_block, 0);
       if (root->left != nullptr || root->right != nullptr ||
           root->begin == root->end) {
         current_function_builder_->EmitWithU8(kExprBr, ARITY_0);
         current_function_builder_->EmitVarInt(default_block);
-        current_function_builder_->Emit(kExprNop);
       }
     }
     for (int i = 0; i < case_count; i++) {
       CaseClause* clause = clauses->at(i);
       RECURSE(VisitStatements(clause->statements()));
       BlockVisitor* v = blocks.at(case_count - i - 1);
       blocks.pop_back();
       delete v;
     }
   }
@@ skipping 1386 matching lines @@
 // that zone in constructor may be thrown away once wasm module is written.
 WasmModuleIndex* AsmWasmBuilder::Run() {
   AsmWasmBuilderImpl impl(isolate_, zone_, literal_, foreign_, typer_);
   impl.Compile();
   WasmModuleWriter* writer = impl.builder_->Build(zone_);
   return writer->WriteTo(zone_);
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8