[wasm] Support for restricted table imports.

src/compiler/wasm-compiler.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/compiler/wasm-compiler.h"
 
 #include <memory>
 
 #include "src/isolate-inl.h"
 
@@ skipping 280 matching lines @@
 
 WasmGraphBuilder::WasmGraphBuilder(
     Zone* zone, JSGraph* jsgraph, wasm::FunctionSig* function_signature,
     compiler::SourcePositionTable* source_position_table)
     : zone_(zone),
       jsgraph_(jsgraph),
       module_(nullptr),
       mem_buffer_(nullptr),
       mem_size_(nullptr),
       function_tables_(zone),
+      function_table_sizes_(zone),
       control_(nullptr),
       effect_(nullptr),
       cur_buffer_(def_buffer_),
       cur_bufsize_(kDefaultBufferSize),
       trap_(new (zone) WasmTrapHelper(this)),
       function_signature_(function_signature),
       source_position_table_(source_position_table) {
   DCHECK_NOT_NULL(jsgraph_);
 }
 
@@ skipping 1394 matching lines @@
                        *effect_, *control_);
   *effect_ = load;
   return load;
 }
 
 Node* WasmGraphBuilder::GrowMemory(Node* input) {
   Diamond check_input_range(
       graph(), jsgraph()->common(),
       graph()->NewNode(
           jsgraph()->machine()->Uint32LessThanOrEqual(), input,
-          jsgraph()->Uint32Constant(wasm::WasmModule::kMaxMemPages)),
+          jsgraph()->Uint32Constant(wasm::WasmModule::kV8MaxPages)),
       BranchHint::kTrue);
 
   check_input_range.Chain(*control_);
 
   Runtime::FunctionId function_id = Runtime::kWasmGrowMemory;
   const Runtime::Function* function = Runtime::FunctionForId(function_id);
   CallDescriptor* desc = Linkage::GetRuntimeCallDescriptor(
       jsgraph()->zone(), function_id, function->nargs, Operator::kNoThrow,
       CallDescriptor::kNoFlags);
   wasm::ModuleEnv* module = module_;
@@ skipping 398 matching lines @@
 
   // Add code object as constant.
   Handle<Code> code = module_->GetFunctionCode(index);
   DCHECK(!code.is_null());
   args[0] = HeapConstant(code);
   wasm::FunctionSig* sig = module_->GetFunctionSignature(index);
 
   return BuildWasmCall(sig, args, rets, position);
 }
 
-Node* WasmGraphBuilder::CallIndirect(uint32_t index, Node** args, Node*** rets,
+Node* WasmGraphBuilder::CallIndirect(uint32_t sig_index, Node** args,
+                                     Node*** rets,
                                      wasm::WasmCodePosition position) {
   DCHECK_NOT_NULL(args[0]);
   DCHECK(module_ && module_->instance);
 
-  MachineOperatorBuilder* machine = jsgraph()->machine();
+  // Assume only one table for now.
+  uint32_t table_index = 0;
+  wasm::FunctionSig* sig = module_->GetSignature(sig_index);
 
-  // Compute the code object by loading it from the function table.
-  Node* key = args[0];
-
-  // Assume only one table for now.
-  DCHECK_LE(module_->instance->function_tables.size(), 1u);
-  // Bounds check the index.
-  uint32_t table_size =
-      module_->IsValidTable(0) ? module_->GetTable(0)->max_size : 0;
-  wasm::FunctionSig* sig = module_->GetSignature(index);
-  if (table_size > 0) {
-    // Bounds check against the table size.
-    Node* size = Uint32Constant(table_size);
-    Node* in_bounds = graph()->NewNode(machine->Uint32LessThan(), key, size);
-    trap_->AddTrapIfFalse(wasm::kTrapFuncInvalid, in_bounds, position);
-  } else {
+  if (!module_->IsValidTable(table_index)) {
     // No function table. Generate a trap and return a constant.
     trap_->AddTrapIfFalse(wasm::kTrapFuncInvalid, Int32Constant(0), position);
     (*rets) = Buffer(sig->return_count());
     for (size_t i = 0; i < sig->return_count(); i++) {
       (*rets)[i] = trap_->GetTrapValue(sig->GetReturn(i));
     }
     return trap_->GetTrapValue(sig);
   }
-  Node* table = FunctionTable(0);
+
+  EnsureFunctionTableNodes();

[bradnelson, 2016/10/28 16:59:01]

Don't care for Ensure, but not sure a good alternative.
I assume Domenic stuck this in here lazily to keep it localized.
Any reason this can't be done up front?

[titzer, 2016/10/28 17:29:08]

Just to save nodes, since I assume most functions don't have direct calls. The
previous code was allocating new nodes every time, which isn't a huge deal. I
also made it easier to extend to multiple tables.

+  MachineOperatorBuilder* machine = jsgraph()->machine();
+  Node* key = args[0];
+
+  // Bounds check against the table size.
+  Node* size = function_table_sizes_[table_index];
+  Node* in_bounds = graph()->NewNode(machine->Uint32LessThan(), key, size);
+  trap_->AddTrapIfFalse(wasm::kTrapFuncInvalid, in_bounds, position);
+  Node* table = function_tables_[table_index];
 
   // Load signature from the table and check.
   // The table is a FixedArray; signatures are encoded as SMIs.
   // [sig1, sig2, sig3, ...., code1, code2, code3 ...]
   ElementAccess access = AccessBuilder::ForFixedArrayElement();
   const int fixed_offset = access.header_size - access.tag();
   {
     Node* load_sig = graph()->NewNode(
         machine->Load(MachineType::AnyTagged()), table,
         graph()->NewNode(machine->Int32Add(),
                          graph()->NewNode(machine->Word32Shl(), key,
                                           Int32Constant(kPointerSizeLog2)),
                          Int32Constant(fixed_offset)),
         *effect_, *control_);
     auto map = const_cast<wasm::SignatureMap&>(
         module_->module->function_tables[0].map);
     Node* sig_match = graph()->NewNode(
         machine->WordEqual(), load_sig,
         jsgraph()->SmiConstant(static_cast<int>(map.FindOrInsert(sig))));
     trap_->AddTrapIfFalse(wasm::kTrapFuncSigMismatch, sig_match, position);
   }
 
   // Load code object from the table.
+  uint32_t table_size = module_->module->function_tables[table_index].min_size;
   uint32_t offset = fixed_offset + kPointerSize * table_size;
   Node* load_code = graph()->NewNode(
       machine->Load(MachineType::AnyTagged()), table,
       graph()->NewNode(machine->Int32Add(),
                        graph()->NewNode(machine->Word32Shl(), key,
                                         Int32Constant(kPointerSizeLog2)),
                        Uint32Constant(offset)),
       *effect_, *control_);
 
   args[0] = load_code;
@@ skipping 626 matching lines @@
     if (!mem_size_)
       mem_size_ = jsgraph()->RelocatableInt32Constant(
           size, RelocInfo::WASM_MEMORY_SIZE_REFERENCE);
     return mem_size_;
   } else {
     return jsgraph()->RelocatableInt32Constant(
         size + offset, RelocInfo::WASM_MEMORY_SIZE_REFERENCE);
   }
 }
 
-Node* WasmGraphBuilder::FunctionTable(uint32_t index) {
-  DCHECK(module_ && module_->instance &&
-         index < module_->instance->function_tables.size());
-  if (!function_tables_.size()) {
-    for (size_t i = 0; i < module_->instance->function_tables.size(); ++i) {
-      DCHECK(!module_->instance->function_tables[i].is_null());
-      function_tables_.push_back(
-          HeapConstant(module_->instance->function_tables[i]));
-    }
+void WasmGraphBuilder::EnsureFunctionTableNodes() {
+  if (function_tables_.size() > 0) return;
+  for (size_t i = 0; i < module_->instance->function_tables.size(); ++i) {
+    auto handle = module_->instance->function_tables[i];
+    DCHECK(!handle.is_null());
+    function_tables_.push_back(HeapConstant(handle));
+    uint32_t table_size = module_->module->function_tables[i].min_size;
+    function_table_sizes_.push_back(Uint32Constant(table_size));
   }
-  return function_tables_[index];
 }
 
 Node* WasmGraphBuilder::GetGlobal(uint32_t index) {
   MachineType mem_type =
       wasm::WasmOpcodes::MachineTypeFor(module_->GetGlobalType(index));
   Node* addr = jsgraph()->RelocatableIntPtrConstant(
       reinterpret_cast<uintptr_t>(module_->instance->globals_start +
                                   module_->module->globals[index].offset),
       RelocInfo::WASM_GLOBAL_REFERENCE);
   const Operator* op = jsgraph()->machine()->Load(mem_type);
@@ skipping 604 matching lines @@
                             function_->code_start_offset),
            compile_ms);
   }
 
   return code;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8