[wasm] Validate the alignment of load and store instructions.

src/wasm/ast-decoder.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/signature.h"
 
 #include "src/bit-vector.h"
 #include "src/flags.h"
 #include "src/handles.h"
 #include "src/zone-containers.h"
@@ skipping 383 matching lines @@
     }
   }
 
   unsigned OpcodeLength(const byte* pc) {
     switch (static_cast<WasmOpcode>(*pc)) {
 #define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
       FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE)
       FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE)
 #undef DECLARE_OPCODE_CASE
       {
-        MemoryAccessOperand operand(this, pc);
+        MemoryAccessOperand operand(this, pc, UINT32_MAX);
         return 1 + operand.length;
       }
       case kExprBr:
       case kExprBrIf: {
         BreakDepthOperand operand(this, pc);
         return 1 + operand.length;
       }
       case kExprSetGlobal:
       case kExprGetGlobal: {
         GlobalIndexOperand operand(this, pc);
@@ skipping 956 matching lines @@
   }
 
   void PopControl() {
     const Control& c = control_.back();
     most_recent_finally_ = c.prev_finally;
     control_.pop_back();
     // No more accesses to (danging pointer) c
   }
 
   int DecodeLoadMem(LocalType type, MachineType mem_type) {
-    MemoryAccessOperand operand(this, pc_);
+    MemoryAccessOperand operand(this, pc_,
+                                ElementSizeLog2Of(mem_type.representation()));
+
     Value index = Pop(0, kAstI32);
     TFNode* node = BUILD(LoadMem, type, mem_type, index.node, operand.offset,
                          operand.alignment, position());
     Push(type, node);
     return 1 + operand.length;
   }
 
   int DecodeStoreMem(LocalType type, MachineType mem_type) {
-    MemoryAccessOperand operand(this, pc_);
+    MemoryAccessOperand operand(this, pc_,
+                                ElementSizeLog2Of(mem_type.representation()));
     Value val = Pop(1, type);
     Value index = Pop(0, kAstI32);
     BUILD(StoreMem, mem_type, index.node, operand.offset, operand.alignment,
           val.node, position());
     Push(type, val.node);
     return 1 + operand.length;
   }
 
   void DecodeSimdOpcode(WasmOpcode opcode) {
     FunctionSig* sig = WasmOpcodes::Signature(opcode);
@@ skipping 663 matching lines @@
 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
                                            const byte* start, const byte* end) {
   FunctionBody body = {nullptr, nullptr, nullptr, start, end};
   WasmFullDecoder decoder(zone, nullptr, body);
   return decoder.AnalyzeLoopAssignmentForTesting(start, num_locals);
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8