[wasm][interpreter] Store code entry as raw pointer

We are currently wrapping the pointer to the instruction start in a
Foreign. The argument buffer, which is also a raw pointer, is passed
directly though.
This CL changes this to also pass the code entry as a raw pointer.

R=mstarzinger@chromium.org

Change-Id: Id7344efa589a5297339ec01c3cfa7688bcc706b3
Reviewed-on: https://chromium-review.googlesource.com/1226970Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55895}

src/compiler/wasm-compiler.cc

@@ -4704,12 +4704,7 @@ class WasmWrapperGraphBuilder : public WasmGraphBuilder {
     SetEffect(SetControl(Start(CWasmEntryParameters::kNumParameters + 5)));
 
     // Create parameter nodes (offset by 1 for the receiver parameter).
-    Node* foreign_code_obj = Param(CWasmEntryParameters::kCodeObject + 1);
-    MachineOperatorBuilder* machine = mcgraph()->machine();
-    Node* code_obj = graph()->NewNode(
-        machine->Load(MachineType::Pointer()), foreign_code_obj,
-        Int32Constant(Foreign::kForeignAddressOffset - kHeapObjectTag),
-        Effect(), Control());
+    Node* code_entry = Param(CWasmEntryParameters::kCodeEntry + 1);
     Node* instance_node = Param(CWasmEntryParameters::kWasmInstance + 1);
     Node* arg_buffer = Param(CWasmEntryParameters::kArgumentsBuffer + 1);
 
@@ -4718,7 +4713,7 @@ class WasmWrapperGraphBuilder : public WasmGraphBuilder {
     Node** args = Buffer(arg_count);
 
     int pos = 0;
-    args[pos++] = code_obj;
+    args[pos++] = code_entry;
     args[pos++] = instance_node;
 
     int offset = 0;

src/compiler/wasm-compiler.h

@@ -88,7 +88,7 @@ MaybeHandle<Code> CompileWasmInterpreterEntry(Isolate*, uint32_t func_index,
                                               wasm::FunctionSig*);
 
 enum CWasmEntryParameters {
-  kCodeObject,
+  kCodeEntry,
   kWasmInstance,
   kArgumentsBuffer,
   // marker:

src/wasm/wasm-interpreter.cc

@@ -2762,17 +2762,19 @@ class ThreadImpl {
       arg_buffer.resize(return_size);
     }
 
-    // Wrap the arg_buffer data pointer in a handle. As
-    // this is an aligned pointer, to the GC it will look like a Smi.
+    // Wrap the arg_buffer and the code target data pointers in handles. As
+    // these are aligned pointers, to the GC it will look like Smis.
     Handle<Object> arg_buffer_obj(reinterpret_cast<Object*>(arg_buffer.data()),
                                   isolate);
     DCHECK(!arg_buffer_obj->IsHeapObject());
+    Handle<Object> code_entry_obj(
+        reinterpret_cast<Object*>(code->instruction_start()), isolate);
+    DCHECK(!code_entry_obj->IsHeapObject());
 
     static_assert(compiler::CWasmEntryParameters::kNumParameters == 3,
                   "code below needs adaption");
     Handle<Object> args[compiler::CWasmEntryParameters::kNumParameters];
-    args[compiler::CWasmEntryParameters::kCodeObject] = Handle<Object>::cast(
-        isolate->factory()->NewForeign(code->instruction_start(), TENURED));
+    args[compiler::CWasmEntryParameters::kCodeEntry] = code_entry_obj;
     args[compiler::CWasmEntryParameters::kWasmInstance] = instance;
     args[compiler::CWasmEntryParameters::kArgumentsBuffer] = arg_buffer_obj;
 

test/cctest/wasm/test-c-wasm-entry.cc

@@ -62,10 +62,11 @@ class CWasmEntryArgTester {
     Handle<Object> buffer_obj(reinterpret_cast<Object*>(arg_buffer.data()),
                               isolate_);
     CHECK(!buffer_obj->IsHeapObject());
-    Handle<Object> call_args[]{
-        Handle<Object>::cast(isolate_->factory()->NewForeign(
-            wasm_code_->instruction_start(), TENURED)),
-        runner_.builder().instance_object(), buffer_obj};
+    Handle<Object> code_entry_obj(
+        reinterpret_cast<Object*>(wasm_code_->instruction_start()), isolate_);
+    CHECK(!code_entry_obj->IsHeapObject());
+    Handle<Object> call_args[]{code_entry_obj,
+                               runner_.builder().instance_object(), buffer_obj};
     static_assert(
         arraysize(call_args) == compiler::CWasmEntryParameters::kNumParameters,
         "adapt this test");