PPC: Crankshaft is now able to compile top level code even if there is a ScriptContext.

Port 29ebcc32

Original commit message:
    This CL introduces HPrologue instruction which does the context allocation work and supports deoptimization.

R=ishell@chromium.org, jyan@ca.ibm.com, dstence@us.ibm.com, joransiu@ca.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1324023002

Cr-Commit-Position: refs/heads/master@{#30516}

src/full-codegen/ppc/full-codegen-ppc.cc

@@ -186,7 +186,7 @@ void FullCodeGenerator::Generate() {
     }
   }
 
-  bool function_in_register = true;
+  bool function_in_register_r4 = true;
 
   // Possibly allocate a local context.
   if (info->scope()->num_heap_slots() > 0) {
@@ -207,7 +207,7 @@ void FullCodeGenerator::Generate() {
       __ push(r4);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
-    function_in_register = false;
+    function_in_register_r4 = false;
     // Context is returned in r3.  It replaces the context passed to us.
     // It's saved in the stack and kept live in cp.
     __ mr(cp, r3);
@@ -240,14 +240,19 @@ void FullCodeGenerator::Generate() {
     }
   }
 
+  PrepareForBailoutForId(BailoutId::Prologue(), NO_REGISTERS);
+  // Function register is trashed in case we bailout here. But since that
+  // could happen only when we allocate a context the value of
+  // |function_in_register_r4| is correct.
+
   // Possibly set up a local binding to the this function which is used in
   // derived constructors with super calls.
   Variable* this_function_var = scope()->this_function_var();
   if (this_function_var != nullptr) {
     Comment cmnt(masm_, "[ This function");
-    if (!function_in_register) {
+    if (!function_in_register_r4) {
       __ LoadP(r4, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
-      // The write barrier clobbers register again, keep is marked as such.
+      // The write barrier clobbers register again, keep it marked as such.
     }
     SetVar(this_function_var, r4, r3, r5);
   }
@@ -271,6 +276,7 @@ void FullCodeGenerator::Generate() {
     __ LoadP(r4, MemOperand(r5, StandardFrameConstants::kMarkerOffset));
     __ CmpSmiLiteral(r4, Smi::FromInt(StackFrame::CONSTRUCT), r0);
     Label non_construct_frame, done;
+    function_in_register_r4 = false;
 
     __ bne(&non_construct_frame);
     __ LoadP(r3, MemOperand(
@@ -298,6 +304,7 @@ void FullCodeGenerator::Generate() {
     __ LoadSmiLiteral(r4, Smi::FromInt(rest_index));
     __ LoadSmiLiteral(r3, Smi::FromInt(language_mode()));
     __ Push(r6, r5, r4, r3);
+    function_in_register_r4 = false;
 
     RestParamAccessStub stub(isolate());
     __ CallStub(&stub);
@@ -309,7 +316,7 @@ void FullCodeGenerator::Generate() {
   if (arguments != NULL) {
     // Function uses arguments object.
     Comment cmnt(masm_, "[ Allocate arguments object");
-    if (!function_in_register) {
+    if (!function_in_register_r4) {
       // Load this again, if it's used by the local context below.
       __ LoadP(r6, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
     } else {

src/ppc/lithium-codegen-ppc.cc

@@ -176,16 +176,27 @@ bool LCodeGen::GeneratePrologue() {
   if (info()->saves_caller_doubles()) {
     SaveCallerDoubles();
   }
+  return !is_aborted();
+}
+
+
+void LCodeGen::DoPrologue(LPrologue* instr) {
+  Comment(";;; Prologue begin");
 
   // Possibly allocate a local context.
-  int heap_slots = info()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
-  if (heap_slots > 0) {
+  if (info()->scope()->num_heap_slots() > 0) {
     Comment(";;; Allocate local context");
     bool need_write_barrier = true;
     // Argument to NewContext is the function, which is in r4.
-    DCHECK(!info()->scope()->is_script_scope());
-    if (heap_slots <= FastNewContextStub::kMaximumSlots) {
-      FastNewContextStub stub(isolate(), heap_slots);
+    int slots = info()->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+    Safepoint::DeoptMode deopt_mode = Safepoint::kNoLazyDeopt;
+    if (info()->scope()->is_script_scope()) {
+      __ push(r4);
+      __ Push(info()->scope()->GetScopeInfo(info()->isolate()));
+      __ CallRuntime(Runtime::kNewScriptContext, 2);
+      deopt_mode = Safepoint::kLazyDeopt;
+    } else if (slots <= FastNewContextStub::kMaximumSlots) {
+      FastNewContextStub stub(isolate(), slots);
       __ CallStub(&stub);
       // Result of FastNewContextStub is always in new space.
       need_write_barrier = false;
@@ -193,7 +204,8 @@ bool LCodeGen::GeneratePrologue() {
       __ push(r4);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
-    RecordSafepoint(Safepoint::kNoLazyDeopt);
+    RecordSafepoint(deopt_mode);
+
     // Context is returned in both r3 and cp.  It replaces the context
     // passed to us.  It's saved in the stack and kept live in cp.
     __ mr(cp, r3);
@@ -226,13 +238,7 @@ bool LCodeGen::GeneratePrologue() {
     Comment(";;; End allocate local context");
   }
 
-  // Trace the call.
-  if (FLAG_trace && info()->IsOptimizing()) {
-    // We have not executed any compiled code yet, so cp still holds the
-    // incoming context.
-    __ CallRuntime(Runtime::kTraceEnter, 0);
-  }
-  return !is_aborted();
+  Comment(";;; Prologue end");
 }
 
 

src/ppc/lithium-ppc.cc

@@ -928,7 +928,7 @@ void LChunkBuilder::AddInstruction(LInstruction* instr,
   }
   chunk_->AddInstruction(instr, current_block_);
 
-  if (instr->IsCall()) {
+  if (instr->IsCall() || instr->IsPrologue()) {
     HValue* hydrogen_value_for_lazy_bailout = hydrogen_val;
     if (hydrogen_val->HasObservableSideEffects()) {
       HSimulate* sim = HSimulate::cast(hydrogen_val->next());
@@ -942,6 +942,11 @@ void LChunkBuilder::AddInstruction(LInstruction* instr,
 }
 
 
+LInstruction* LChunkBuilder::DoPrologue(HPrologue* instr) {
+  return new (zone()) LPrologue();
+}
+
+
 LInstruction* LChunkBuilder::DoGoto(HGoto* instr) {
   return new (zone()) LGoto(instr->FirstSuccessor());
 }

src/ppc/lithium-ppc.h

@@ -131,6 +131,7 @@ class LCodeGen;
   V(OsrEntry)                                \
   V(Parameter)                               \
   V(Power)                                   \
+  V(Prologue)                                \
   V(PushArgument)                            \
   V(RegExpLiteral)                           \
   V(Return)                                  \
@@ -384,6 +385,12 @@ class LGoto final : public LTemplateInstruction<0, 0, 0> {
 };
 
 
+class LPrologue final : public LTemplateInstruction<0, 0, 0> {
+ public:
+  DECLARE_CONCRETE_INSTRUCTION(Prologue, "prologue")
+};
+
+
 class LLazyBailout final : public LTemplateInstruction<0, 0, 0> {
  public:
   LLazyBailout() : gap_instructions_size_(0) {}