[wasm] Remove TableSwitch and replace with br_table.

src/wasm/ast-decoder.h

 // 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.
 
 #ifndef V8_WASM_AST_DECODER_H_
 #define V8_WASM_AST_DECODER_H_
 
 #include "src/signature.h"
 #include "src/wasm/decoder.h"
 #include "src/wasm/wasm-opcodes.h"
@@ skipping 124 matching lines @@
 struct ImportIndexOperand {
   uint32_t index;
   FunctionSig* sig;
   int length;
   inline ImportIndexOperand(Decoder* decoder, const byte* pc) {
     index = decoder->checked_read_u32v(pc, 1, &length, "import index");
     sig = nullptr;
   }
 };
 
-struct TableSwitchOperand {
-  uint32_t case_count;
+struct BranchTableOperand {
   uint32_t table_count;
   const byte* table;
   int length;
-  inline TableSwitchOperand(Decoder* decoder, const byte* pc) {
-    case_count = decoder->checked_read_u16(pc, 1, "expected #cases");
-    table_count = decoder->checked_read_u16(pc, 3, "expected #entries");
-    length = 4 + table_count * 2;
+  inline BranchTableOperand(Decoder* decoder, const byte* pc) {
+    table_count = decoder->checked_read_u16(pc, 1, "expected #entries");
+    length = 2 + table_count * 2 + 2;
 
-    if (decoder->check(pc, 5, table_count * 2, "expected <table entries>")) {
-      table = pc + 5;
+    if (decoder->check(pc, 3, table_count * 2 + 2,
+                       "expected <table entries>")) {
+      table = pc + 3;
     } else {
       table = nullptr;
     }
   }
   inline uint16_t read_entry(Decoder* decoder, int i) {
-    DCHECK(i >= 0 && static_cast<uint32_t>(i) < table_count);
+    DCHECK(i >= 0 && static_cast<uint32_t>(i) <= table_count);
     return table ? decoder->read_u16(table + i * sizeof(uint16_t)) : 0;
   }
 };
 
 struct MemoryAccessOperand {
   bool aligned;
   uint32_t offset;
   int length;
   inline MemoryAccessOperand(Decoder* decoder, const byte* pc) {
     byte bitfield = decoder->checked_read_u8(pc, 1, "memory access byte");
@@ skipping 101 matching lines @@
 // Computes the length of the opcode at the given address.
 int OpcodeLength(const byte* pc, const byte* end);
 
 // Computes the arity (number of sub-nodes) of the opcode at the given address.
 int OpcodeArity(FunctionEnv* env, const byte* pc, const byte* end);
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_WASM_AST_DECODER_H_