[wasm] remove faux code objects

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 "src/isolate-inl.h"
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/base/platform/platform.h"
@@ skipping 1856 matching lines @@
   CallDescriptor* desc =
       Linkage::GetSimplifiedCDescriptor(jsgraph()->zone(), sig);
 
   const Operator* op = jsgraph()->common()->Call(desc);
   Node* call = graph()->NewNode(op, static_cast<int>(count), args);
   *effect_ = call;
   return call;
 }
 
 Node* WasmGraphBuilder::BuildWasmCall(wasm::FunctionSig* sig, Node** args,
-                                      wasm::WasmCodePosition position) {
+                                      wasm::WasmCodePosition position,
+                                      bool internal) {
   const size_t params = sig->parameter_count();
   const size_t extra = 2;  // effect and control inputs.
   const size_t count = 1 + params + extra;
 
   // Reallocate the buffer to make space for extra inputs.
   args = Realloc(args, 1 + params, count);
 
   // Add effect and control inputs.
   args[params + 1] = *effect_;
   args[params + 2] = *control_;
 
   CallDescriptor* descriptor =
-      wasm::ModuleEnv::GetWasmCallDescriptor(jsgraph()->zone(), sig);
+      wasm::ModuleEnv::GetWasmCallDescriptor(jsgraph()->zone(), sig, internal);
   const Operator* op = jsgraph()->common()->Call(descriptor);
   Node* call = graph()->NewNode(op, static_cast<int>(count), args);
   SetSourcePosition(call, position);
 
   *effect_ = call;
   return call;
 }
 
 Node* WasmGraphBuilder::CallDirect(uint32_t index, Node** args,
                                    wasm::WasmCodePosition position) {
   DCHECK_NULL(args[0]);
 
-  // Add code object as constant.
-  args[0] = HeapConstant(module_->GetCodeOrPlaceholder(index));
+  args[0] =
+      jsgraph()->RelocatableInt32Constant(index, RelocInfo::WASM_DIRECT_CALL);
   wasm::FunctionSig* sig = module_->GetFunctionSignature(index);
 
-  return BuildWasmCall(sig, args, position);
+  return BuildWasmCall(sig, args, position, true);
 }
 
 Node* WasmGraphBuilder::CallImport(uint32_t index, Node** args,
                                    wasm::WasmCodePosition position) {
   DCHECK_NULL(args[0]);
 
-  // Add code object as constant.
-  args[0] = HeapConstant(module_->GetImportCode(index));
+  args[0] =
+      jsgraph()->RelocatableInt32Constant(index, RelocInfo::WASM_IMPORT_CALL);
   wasm::FunctionSig* sig = module_->GetImportSignature(index);
-
-  return BuildWasmCall(sig, args, position);
+  return BuildWasmCall(sig, args, position, true);
 }
 
 Node* WasmGraphBuilder::CallIndirect(uint32_t index, Node** args,
                                      wasm::WasmCodePosition position) {
   DCHECK_NOT_NULL(args[0]);
   DCHECK(module_ && module_->instance);
 
   MachineOperatorBuilder* machine = jsgraph()->machine();
 
   // Compute the code object by loading it from the function table.
@@ skipping 1366 matching lines @@
     double compile_ms = compile_timer.Elapsed().InMillisecondsF();
     PrintF("wasm-code-generation ok: %d bytes, %0.3f ms code generation\n",
            static_cast<int>(function_->code_end_offset -
                             function_->code_start_offset),
            compile_ms);
   }
 
   return code;
 }
 
+void Link(Isolate* isolate, std::vector<Handle<Code>>& unlinked_functions,
+          const std::vector<Handle<Code>>& functions_to_link, int mode_mask) {
+  // On architectures supporting constant pools, if a function A calls another
+  // function B in a number of places, then the same slot in the constant pool
+  // would be used for the call to B. We can't update eagerly the location,
+  // because that would mean that the next time we look at the location to find
+  // the index of the function being called, we'd find the actual address
+  // instead. So we keep a worklist. To keep the code simple, we maintain the
+  // worklist even on architectures that do not support constant pools.
+
+  std::vector<std::pair<RelocInfo, Address>> worklist;
+  {
+    DisallowHeapAllocation no_gc_scope;
+    RelocInfoWriter writer;
+    for (Handle<Code> code : unlinked_functions) {
+      AllowDeferredHandleDereference embedding_raw_address;
+      for (RelocIterator it(*code, mode_mask); !it.done(); it.next()) {
+        size_t f_index = it.rinfo()->wasm_function_index();
+        Handle<Code> to_link = functions_to_link[f_index];
+        worklist.push_back(
+            std::make_pair(*it.rinfo(), to_link->instruction_start()));
+        writer.Reposition(it.mode_pos(), it.rinfo()->pc());
+        writer.WriteModeNoAdvance(RelocInfo::CODE_TARGET);
+      }
+      for (auto pair : worklist) {
+        pair.first.set_target_address(pair.second, SKIP_WRITE_BARRIER,
+                                      SKIP_ICACHE_FLUSH);
+      }
+      if (!worklist.empty()) {
+        worklist.clear();
+        Assembler::FlushICache(isolate, code->instruction_start(),
+                               code->instruction_size());
+      }
+    }
+  }
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8