[wasm] Use constant table size when possible

This patch constantize the table size, both for primary and secondary tables, whenever the table size
is known to never change.

By default WebAssebly tables can be grown indefinitely, but producers can specify a maximal limit.
In particular, producers can specify that the initial size of the table also correspond to the
maximum size, in which case the table cannot be grown and the size is constant.

This is a common case, for example when generating WebAssembly from a C++ codebase the list
of indirectly called function does not need, in general, to change at runtime.

Change-Id: I7f6bab60841ee8eb8bdfd996c34513f69b74d5d2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2912586Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74760}

src/compiler/wasm-compiler.cc

@@ -3012,9 +3012,18 @@ void WasmGraphBuilder::LoadIndirectFunctionTable(uint32_t table_index,
                                                  Node** ift_sig_ids,
                                                  Node** ift_targets,
                                                  Node** ift_instances) {
+  bool needs_dynamic_size = true;
+  const wasm::WasmTable& table = env_->module->tables[table_index];
+  if (table.has_maximum_size && table.maximum_size == table.initial_size) {
+    *ift_size = Int32Constant(table.initial_size);
+    needs_dynamic_size = false;
+  }
+
   if (table_index == 0) {
-    *ift_size = LOAD_MUTABLE_INSTANCE_FIELD(IndirectFunctionTableSize,
-                                            MachineType::Uint32());
+    if (needs_dynamic_size) {
+      *ift_size = LOAD_MUTABLE_INSTANCE_FIELD(IndirectFunctionTableSize,
+                                              MachineType::Uint32());
+    }
     *ift_sig_ids = LOAD_MUTABLE_INSTANCE_FIELD(IndirectFunctionTableSigIds,
                                                MachineType::Pointer());
     *ift_targets = LOAD_MUTABLE_INSTANCE_FIELD(IndirectFunctionTableTargets,
@@ -3028,9 +3037,11 @@ void WasmGraphBuilder::LoadIndirectFunctionTable(uint32_t table_index,
                                                  MachineType::TaggedPointer());
   Node* ift_table = gasm_->LoadFixedArrayElementAny(ift_tables, table_index);
 
-  *ift_size = gasm_->LoadFromObject(
-      MachineType::Int32(), ift_table,
-      wasm::ObjectAccess::ToTagged(WasmIndirectFunctionTable::kSizeOffset));
+  if (needs_dynamic_size) {
+    *ift_size = gasm_->LoadFromObject(
+        MachineType::Int32(), ift_table,
+        wasm::ObjectAccess::ToTagged(WasmIndirectFunctionTable::kSizeOffset));
+  }
 
   *ift_sig_ids = gasm_->LoadFromObject(
       MachineType::Pointer(), ift_table,