[compiler] only enable MidTierRegisterAllocator for Wasm

The mid-tier register allocator keeps values in stack slots for too
long. This is incompatible with left-trimming, therefore we cannot
enable it for JS functions.

Bug: chromium:1335054
Change-Id: I61ab97d4fbfcbb81319e611a64a6454e050a1d65
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3695266Reviewed-by: Clemens Backes <clemensb@chromium.org>
Auto-Submit: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81070}

src/compiler/pipeline.cc

@@ -3659,8 +3659,11 @@ bool PipelineImpl::SelectInstructions(Linkage* linkage) {
 
   const RegisterConfiguration* config = RegisterConfiguration::Default();
   std::unique_ptr<const RegisterConfiguration> restricted_config;
+  // The mid-tier register allocator keeps values in stack slots for too long.
+  // This is incompatible with left-trimming, therefore we cannot enable it for
+  // JS functions.
   bool use_mid_tier_register_allocator =
-      !CodeKindIsStaticallyCompiled(data->info()->code_kind()) &&
+      data->info()->code_kind() == CodeKind::WASM_FUNCTION &&
       (FLAG_turbo_force_mid_tier_regalloc ||
        (FLAG_turbo_use_mid_tier_regalloc_for_huge_functions &&
         data->sequence()->VirtualRegisterCount() >

src/objects/code-kind.h

@@ -57,10 +57,6 @@ inline constexpr bool CodeKindIsBaselinedJSFunction(CodeKind kind) {
   return kind == CodeKind::BASELINE;
 }
 
-inline constexpr bool CodeKindIsStaticallyCompiled(CodeKind kind) {
-  return kind == CodeKind::BYTECODE_HANDLER || kind == CodeKind::BUILTIN;
-}
-
 inline constexpr bool CodeKindIsUnoptimizedJSFunction(CodeKind kind) {
   static_assert(static_cast<int>(CodeKind::INTERPRETED_FUNCTION) + 1 ==
                 static_cast<int>(CodeKind::BASELINE));