[codegen] Block const pool emission in safepoint table

We cannot emit the constant pool within the safepoint table data. It
seems like we also don't do that, but the forgotten
{BlockConstPoolScope} triggered a DCHECK.

R=leszeks@chromium.org

Bug: chromium:1227351, chromium:1217074
Change-Id: I187004c83e05002c651a15643bddea5b02cb00c3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3015559Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75657}

src/codegen/safepoint-table.cc

@@ -113,6 +113,11 @@ void SafepointTableBuilder::Emit(Assembler* assembler, int bits_per_entry) {
   RemoveDuplicates();
   TrimEntries(&bits_per_entry);
 
+#if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_ARM64
+  // We cannot emit a const pool within the safepoint table.
+  Assembler::BlockConstPoolScope block_const_pool(assembler);
+#endif
+
   // Make sure the safepoint table is properly aligned. Pad with nops.
   assembler->Align(Code::kMetadataAlignment);
   assembler->RecordComment(";;; Safepoint table.");

test/mjsunit/regress/wasm/regress-1227351.js

+// Copyright 2021 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.
+
+// Flags: --wasm-staging
+
+load('test/mjsunit/wasm/wasm-module-builder.js');
+
+const builder = new WasmModuleBuilder();
+builder.addFunction(undefined, kSig_d_v)
+    .addLocals(kWasmExternRef, 16000)
+    .addBody([kExprCallFunction, 0]);
+builder.toModule();