PPC: use DirectCEntry for regexp code

Change-Id: I9bd7c97dd0b36935bd1fb76cd2cbc83a1b28cdfb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1521223
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Auto-Submit: Junliang Yan <jyan@ca.ibm.com>
Reviewed-by: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#60223}

src/builtins/ppc/builtins-ppc.cc

@@ -3272,8 +3272,21 @@ void Builtins::Generate_CallApiGetter(MacroAssembler* masm) {
 }
 
 void Builtins::Generate_DirectCEntry(MacroAssembler* masm) {
-  // Unused.
-  __ stop(0);
+  // Place the return address on the stack, making the call
+  // GC safe. The RegExp backend also relies on this.
+  __ mflr(r0);
+  __ StoreP(r0, MemOperand(sp, kStackFrameExtraParamSlot * kPointerSize));
+
+  if (ABI_USES_FUNCTION_DESCRIPTORS && FLAG_embedded_builtins) {
+    // AIX/PPC64BE Linux use a function descriptor;
+    __ LoadP(ToRegister(ABI_TOC_REGISTER), MemOperand(ip, kPointerSize));
+    __ LoadP(ip, MemOperand(ip, 0));  // Instruction address
+  }
+
+  __ Call(ip);  // Call the C++ function.
+  __ LoadP(r0, MemOperand(sp, kStackFrameExtraParamSlot * kPointerSize));
+  __ mtlr(r0);
+  __ blr();
 }
 
 #undef __

src/regexp/ppc/regexp-macro-assembler-ppc.cc

@@ -1131,7 +1131,19 @@ void RegExpMacroAssemblerPPC::CallCheckStackGuardState(Register scratch) {
   ExternalReference stack_guard_check =
       ExternalReference::re_check_stack_guard_state(isolate());
   __ mov(ip, Operand(stack_guard_check));
-  __ StoreReturnAddressAndCall(ip);
+
+  if (FLAG_embedded_builtins) {
+    EmbeddedData d = EmbeddedData::FromBlob();
+    CHECK(Builtins::IsIsolateIndependent(Builtins::kDirectCEntry));
+    Address entry = d.InstructionStartOfBuiltin(Builtins::kDirectCEntry);
+    __ mov(r0, Operand(entry, RelocInfo::OFF_HEAP_TARGET));
+  } else {
+    // TODO(v8:8519): Remove this once embedded builtins are on unconditionally.
+    Handle<Code> code = BUILTIN_CODE(isolate(), DirectCEntry);
+    __ mov(r0, Operand(reinterpret_cast<intptr_t>(code.location()),
+                       RelocInfo::CODE_TARGET));
+  }
+  __ Call(r0);
 
   // Restore the stack pointer
   stack_space = kNumRequiredStackFrameSlots + stack_passed_arguments;