[wasm] Remove MemoryAccessImmediate constructor

When we later introduce an additional template argument to WasmDecoder,
we will have to add it here too, as well as in all places which use
MemoryAccessImmediate. It is simpler to have a helper function in
WasmDecoder to fetch the 64-bit memory status.

Bug: v8:11895
Change-Id: I08edbf4e825cd148b30b2a5c0d04a26dfbaed186
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2972905
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75252}

src/wasm/function-body-decoder-impl.h

@@ -703,9 +703,6 @@ struct MemoryAccessImmediate {
                                pc + alignment_length, &offset_length, "offset");
     length = alignment_length + offset_length;
   }
-  // Defined below, after the definition of WasmDecoder.
-  inline MemoryAccessImmediate(WasmDecoder<validate>* decoder, const byte* pc,
-                               uint32_t max_alignment);
 };
 
 // Immediate for SIMD lane operations.
@@ -2080,12 +2077,6 @@ class WasmDecoder : public Decoder {
   const FunctionSig* sig_;
 };
 
-template <Decoder::ValidateFlag validate>
-MemoryAccessImmediate<validate>::MemoryAccessImmediate(
-    WasmDecoder<validate>* decoder, const byte* pc, uint32_t max_alignment)
-    : MemoryAccessImmediate(decoder, pc, max_alignment,
-                            decoder->module_->is_memory64) {}
-
 // Only call this in contexts where {current_code_reachable_and_ok_} is known to
 // hold.
 #define CALL_INTERFACE(name, ...)                         \
@@ -2282,6 +2273,12 @@ class WasmFullDecoder : public WasmDecoder<validate> {
     return true;
   }
 
+  MemoryAccessImmediate<validate> MakeMemoryAccessImmediate(
+      uint32_t pc_offset, uint32_t max_alignment) {
+    return MemoryAccessImmediate<validate>(
+        this, this->pc_ + pc_offset, max_alignment, this->module_->is_memory64);
+  }
+
 #ifdef DEBUG
   class TraceLine {
    public:
@@ -3610,8 +3607,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
   }
 
   int DecodeLoadMem(LoadType type, int prefix_len = 1) {
-    MemoryAccessImmediate<validate> imm(this, this->pc_ + prefix_len,
-                                        type.size_log_2());
+    MemoryAccessImmediate<validate> imm =
+        MakeMemoryAccessImmediate(prefix_len, type.size_log_2());
     if (!this->Validate(this->pc_ + prefix_len, imm)) return 0;
     ValueType index_type = this->module_->is_memory64 ? kWasmI64 : kWasmI32;
     Value index = Peek(0, 0, index_type);
@@ -3627,8 +3624,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
     // Load extends always load 64-bits.
     uint32_t max_alignment =
         transform == LoadTransformationKind::kExtend ? 3 : type.size_log_2();
-    MemoryAccessImmediate<validate> imm(this, this->pc_ + opcode_length,
-                                        max_alignment);
+    MemoryAccessImmediate<validate> imm =
+        MakeMemoryAccessImmediate(opcode_length, max_alignment);
     if (!this->Validate(this->pc_ + opcode_length, imm)) return 0;
     ValueType index_type = this->module_->is_memory64 ? kWasmI64 : kWasmI32;
     Value index = Peek(0, 0, index_type);
@@ -3641,8 +3638,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
   }
 
   int DecodeLoadLane(WasmOpcode opcode, LoadType type, uint32_t opcode_length) {
-    MemoryAccessImmediate<validate> mem_imm(this, this->pc_ + opcode_length,
-                                            type.size_log_2());
+    MemoryAccessImmediate<validate> mem_imm =
+        MakeMemoryAccessImmediate(opcode_length, type.size_log_2());
     if (!this->Validate(this->pc_ + opcode_length, mem_imm)) return 0;
     SimdLaneImmediate<validate> lane_imm(
         this, this->pc_ + opcode_length + mem_imm.length);
@@ -3660,8 +3657,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
 
   int DecodeStoreLane(WasmOpcode opcode, StoreType type,
                       uint32_t opcode_length) {
-    MemoryAccessImmediate<validate> mem_imm(this, this->pc_ + opcode_length,
-                                            type.size_log_2());
+    MemoryAccessImmediate<validate> mem_imm =
+        MakeMemoryAccessImmediate(opcode_length, type.size_log_2());
     if (!this->Validate(this->pc_ + opcode_length, mem_imm)) return 0;
     SimdLaneImmediate<validate> lane_imm(
         this, this->pc_ + opcode_length + mem_imm.length);
@@ -3676,8 +3673,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
   }
 
   int DecodeStoreMem(StoreType store, int prefix_len = 1) {
-    MemoryAccessImmediate<validate> imm(this, this->pc_ + prefix_len,
-                                        store.size_log_2());
+    MemoryAccessImmediate<validate> imm =
+        MakeMemoryAccessImmediate(prefix_len, store.size_log_2());
     if (!this->Validate(this->pc_ + prefix_len, imm)) return 0;
     Value value = Peek(0, 1, store.value_type());
     ValueType index_type = this->module_->is_memory64 ? kWasmI64 : kWasmI32;
@@ -4591,9 +4588,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
         return 0;
     }
 
-    MemoryAccessImmediate<validate> imm(
-        this, this->pc_ + opcode_length,
-        ElementSizeLog2Of(memtype.representation()));
+    MemoryAccessImmediate<validate> imm = MakeMemoryAccessImmediate(
+        opcode_length, ElementSizeLog2Of(memtype.representation()));
     if (!this->Validate(this->pc_ + opcode_length, imm)) return false;
 
     // TODO(10949): Fix this for memory64 (index type should be kWasmI64