[wasm] Re-enable Simd lowering tests for wasm

This adds a new simd lowering execution mode for
simd and re-enables the lowering tests

R=titzer@chromium.org,gdeepti@chromium.org,bbudge@chromium.org,mtrofin@chromium.org
BUG=v8:6020

Change-Id: Ice6b7ff2f5973804d379c88241d49b811429a965
Reviewed-on: https://chromium-review.googlesource.com/698928
Commit-Queue: Aseem Garg <aseemgarg@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48322}

src/compiler/wasm-compiler.cc

@@ -4619,7 +4619,8 @@ SourcePositionTable* WasmCompilationUnit::BuildGraphForWasmFunction(
 
   builder.LowerInt64();
 
-  if (builder.has_simd() && !CpuFeatures::SupportsWasmSimd128()) {
+  if (builder.has_simd() &&
+      (!CpuFeatures::SupportsWasmSimd128() || lower_simd_)) {
     SimdScalarLowering(jsgraph_, func_body_.sig).LowerGraph();
   }
 
@@ -4656,7 +4657,8 @@ Vector<const char> GetDebugName(Zone* zone, wasm::WasmName name, int index) {
 WasmCompilationUnit::WasmCompilationUnit(
     Isolate* isolate, ModuleEnv* env, wasm::FunctionBody body,
     wasm::WasmName name, int index, Handle<Code> centry_stub,
-    Counters* counters, RuntimeExceptionSupport exception_support)
+    Counters* counters, RuntimeExceptionSupport exception_support,
+    bool lower_simd)
     : isolate_(isolate),
       env_(env),
       func_body_(body),
@@ -4664,7 +4666,8 @@ WasmCompilationUnit::WasmCompilationUnit(
       counters_(counters ? counters : isolate->counters()),
       centry_stub_(centry_stub),
       func_index_(index),
-      runtime_exception_support_(exception_support) {}
+      runtime_exception_support_(exception_support),
+      lower_simd_(lower_simd) {}
 
 void WasmCompilationUnit::ExecuteCompilation() {
   auto timed_histogram = env_->module->is_wasm()

src/compiler/wasm-compiler.h

@@ -88,7 +88,8 @@ class WasmCompilationUnit final {
   // only allowed to happen on the foreground thread.
   WasmCompilationUnit(Isolate*, ModuleEnv*, wasm::FunctionBody, wasm::WasmName,
                       int index, Handle<Code> centry_stub, Counters* = nullptr,
-                      RuntimeExceptionSupport = kRuntimeExceptionSupport);
+                      RuntimeExceptionSupport = kRuntimeExceptionSupport,
+                      bool lower_simd = false);
 
   int func_index() const { return func_index_; }
 
@@ -105,6 +106,7 @@ class WasmCompilationUnit final {
 
  private:
   SourcePositionTable* BuildGraphForWasmFunction(double* decode_ms);
+  Counters* counters() { return counters_; }
 
   Isolate* isolate_;
   ModuleEnv* env_;
@@ -127,8 +129,7 @@ class WasmCompilationUnit final {
   RuntimeExceptionSupport runtime_exception_support_;
   bool ok_ = true;
   size_t memory_cost_ = 0;
-
-  Counters* counters() { return counters_; }
+  bool lower_simd_;
 
   DISALLOW_COPY_AND_ASSIGN(WasmCompilationUnit);
 };

test/cctest/wasm/wasm-run-utils.cc

@@ -22,7 +22,8 @@ TestingModuleBuilder::TestingModuleBuilder(
       mem_start_(nullptr),
       mem_size_(0),
       interpreter_(nullptr),
-      runtime_exception_support_(exception_support) {
+      runtime_exception_support_(exception_support),
+      lower_simd_(mode == kExecuteSimdLowered) {
   WasmJs::Install(isolate_, true);
   test_module_.globals_size = kMaxGlobalsSize;
   memset(globals_data_, 0, sizeof(globals_data_));
@@ -429,7 +430,7 @@ void WasmFunctionCompiler::Build(const byte* start, const byte* end) {
   compiler::WasmCompilationUnit unit(
       isolate(), &module_env, func_body, func_name, function_->func_index,
       CEntryStub(isolate(), 1).GetCode(), isolate()->counters(),
-      builder_->runtime_exception_support());
+      builder_->runtime_exception_support(), builder_->lower_simd());
   unit.ExecuteCompilation();
   Handle<Code> code = unit.FinishCompilation(&thrower).ToHandleChecked();
   CHECK(!thrower.error());

test/cctest/wasm/wasm-run-utils.h

@@ -47,7 +47,11 @@ namespace wasm {
 constexpr uint32_t kMaxFunctions = 10;
 constexpr uint32_t kMaxGlobalsSize = 128;
 
-enum WasmExecutionMode { kExecuteInterpreted, kExecuteCompiled };
+enum WasmExecutionMode {
+  kExecuteInterpreted,
+  kExecuteCompiled,
+  kExecuteSimdLowered
+};
 
 using compiler::CallDescriptor;
 using compiler::MachineTypeForC;
@@ -187,6 +191,7 @@ class TestingModuleBuilder {
 
   WasmInterpreter* interpreter() { return interpreter_; }
   bool interpret() { return interpreter_ != nullptr; }
+  bool lower_simd() { return lower_simd_; }
   Isolate* isolate() { return isolate_; }
   Handle<WasmInstanceObject> instance_object() { return instance_object_; }
   Handle<Code> GetFunctionCode(int index) { return function_code_[index]; }
@@ -215,6 +220,7 @@ class TestingModuleBuilder {
   WasmInterpreter* interpreter_;
   Handle<WasmInstanceObject> instance_object_;
   compiler::RuntimeExceptionSupport runtime_exception_support_;
+  bool lower_simd_;
 
   const WasmGlobal* AddGlobal(ValueType type);