PPC/s390: [builtins] implement RunMicrotasks pump as a code stub

Port 52ff3ae4

Original Commit Message:

    - Implement RunMicrotasks in CSA to prevent a potentially large number
      of jumps between C++ and JS code while consuming te queue. Appears to
      provide a ~60% speedup in microtask-heavy code, which from limited
      testing appears to scale linearly.

      The code-stub microtask pump bails out to the old C++ microtask pump
      if it encounters a CallHandlerInfo microtask, and remains in C++ for
      the remainder of the queue (returning to the JS/stub implementation
      after the bailed out queue is exhausted).

    - Add a variation of JSEntryStub which enters the new RunMicrotasks code
      stub.

    - Add a new RunMicrotasks helper to Execution, which uses the
      RunMicrotasks entry stub.

R=caitp@igalia.com, joransiu@ca.ibm.com, jbarboza@ca.ibm.com
BUG=
LOG=N

Change-Id: Ifa15ca19312bb92758e82d19c3e3fc0a8b908d82
Reviewed-on: https://chromium-review.googlesource.com/820197Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#50018}

src/builtins/ppc/builtins-ppc.cc

@@ -643,8 +643,6 @@ static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
     __ mov(cp, Operand(context_address));
     __ LoadP(cp, MemOperand(cp));
 
-    __ InitializeRootRegister();
-
     // Push the function and the receiver onto the stack.
     __ Push(r4, r5);
 

src/builtins/s390/builtins-s390.cc

@@ -639,8 +639,6 @@ static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
     __ mov(cp, Operand(context_address));
     __ LoadP(cp, MemOperand(cp));
 
-    __ InitializeRootRegister();
-
     // Push the function and the receiver onto the stack.
     __ Push(r3, r4);
 

src/ppc/code-stubs-ppc.cc

@@ -489,6 +489,8 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
   // Set up the reserved register for 0.0.
   __ LoadDoubleLiteral(kDoubleRegZero, Double(0.0), r0);
 
+  __ InitializeRootRegister();
+
   // Push a frame with special values setup to mark it as an entry frame.
   // r3: code entry
   // r4: function
@@ -566,12 +568,7 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
   // r5: receiver
   // r6: argc
   // r7: argv
-  if (type() == StackFrame::CONSTRUCT_ENTRY) {
-    __ Call(BUILTIN_CODE(isolate(), JSConstructEntryTrampoline),
-            RelocInfo::CODE_TARGET);
-  } else {
-    __ Call(BUILTIN_CODE(isolate(), JSEntryTrampoline), RelocInfo::CODE_TARGET);
-  }
+  __ Call(EntryTrampoline(), RelocInfo::CODE_TARGET);
 
   // Unlink this frame from the handler chain.
   __ PopStackHandler();

src/s390/code-stubs-s390.cc

@@ -495,6 +495,7 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
   //   kCEntryFPAddress
   //   Frame type
   __ lay(sp, MemOperand(sp, -5 * kPointerSize));
+
   // Push a bad frame pointer to fail if it is used.
   __ LoadImmP(r10, Operand(-1));
 
@@ -512,6 +513,8 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
   __ lay(fp,
          MemOperand(sp, -EntryFrameConstants::kCallerFPOffset + kPointerSize));
 
+  __ InitializeRootRegister();
+
   // If this is the outermost JS call, set js_entry_sp value.
   Label non_outermost_js;
   ExternalReference js_entry_sp(IsolateAddressId::kJSEntrySPAddress, isolate());
@@ -564,12 +567,7 @@ void JSEntryStub::Generate(MacroAssembler* masm) {
   // r4: receiver
   // r5: argc
   // r6: argv
-  if (type() == StackFrame::CONSTRUCT_ENTRY) {
-    __ Call(BUILTIN_CODE(isolate(), JSConstructEntryTrampoline),
-            RelocInfo::CODE_TARGET);
-  } else {
-    __ Call(BUILTIN_CODE(isolate(), JSEntryTrampoline), RelocInfo::CODE_TARGET);
-  }
+  __ Call(EntryTrampoline(), RelocInfo::CODE_TARGET);
 
   // Unlink this frame from the handler chain.
   __ PopStackHandler();