X87: Crankshaft is now able to compile top level code even if there is a ScriptContext.

port 29ebcc32 (r30496).

original commit message:

    This CL introduces HPrologue instruction which does the context allocation work and supports deoptimization.

BUG=

Review URL: https://codereview.chromium.org/1308743005

Cr-Commit-Position: refs/heads/master@{#30606}

src/full-codegen/x87/full-codegen-x87.cc

@@ -229,6 +229,11 @@ 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| 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();

src/x87/lithium-codegen-x87.cc

@@ -215,16 +215,27 @@ bool LCodeGen::GeneratePrologue() {
       }
     }
   }
+  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_->num_heap_slots() > 0) {
     Comment(";;; Allocate local context");
     bool need_write_barrier = true;
     // Argument to NewContext is the function, which is still in edi.
-    DCHECK(!info()->scope()->is_script_scope());
-    if (heap_slots <= FastNewContextStub::kMaximumSlots) {
-      FastNewContextStub stub(isolate(), heap_slots);
+    int slots = info_->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
+    Safepoint::DeoptMode deopt_mode = Safepoint::kNoLazyDeopt;
+    if (info()->scope()->is_script_scope()) {
+      __ push(edi);
+      __ 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;
@@ -232,7 +243,8 @@ bool LCodeGen::GeneratePrologue() {
       __ push(edi);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
-    RecordSafepoint(Safepoint::kNoLazyDeopt);
+    RecordSafepoint(deopt_mode);
+
     // Context is returned in eax.  It replaces the context passed to us.
     // It's saved in the stack and kept live in esi.
     __ mov(esi, eax);
@@ -268,13 +280,8 @@ bool LCodeGen::GeneratePrologue() {
 
   // Initailize FPU state.
   __ fninit();
-  // Trace the call.
-  if (FLAG_trace && info()->IsOptimizing()) {
-    // We have not executed any compiled code yet, so esi still holds the
-    // incoming context.
-    __ CallRuntime(Runtime::kTraceEnter, 0);
-  }
-  return !is_aborted();
+
+  Comment(";;; Prologue end");
 }
 
 

src/x87/lithium-x87.cc

@@ -973,7 +973,7 @@ 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());
@@ -987,6 +987,11 @@ 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/x87/lithium-x87.h

@@ -134,6 +134,7 @@ class LCodeGen;
   V(OsrEntry)                                \
   V(Parameter)                               \
   V(Power)                                   \
+  V(Prologue)                                \
   V(PushArgument)                            \
   V(RegExpLiteral)                           \
   V(Return)                                  \
@@ -410,6 +411,12 @@ 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:
   DECLARE_CONCRETE_INSTRUCTION(LazyBailout, "lazy-bailout")