Out-of-line constant pool on Arm: Stage 3 - Set Constant Pool Pointer on Function Entry

src/arm/builtins-arm.cc

Index: src/arm/builtins-arm.cc
diff --git a/src/arm/builtins-arm.cc b/src/arm/builtins-arm.cc
index 7ae29242b2e48d68d5a96cd40abe0ebab610a48a..eae6f74bdebb07a3984f4df6f929b92a76e37f3d 100644
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -622,12 +622,13 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
       masm->isolate()->heap()->SetConstructStubDeoptPCOffset(masm->pc_offset());
     }
 
-    // Restore context from the frame.
+    // Restore context and pool pointer from the frame.
     // r0: result
     // sp[0]: receiver
     // sp[1]: constructor function
     // sp[2]: number of arguments (smi-tagged)
     __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
+    __ RestoreConstantPoolPointer();
 
     // If the result is an object (in the ECMA sense), we should get rid
     // of the receiver and use the result; see ECMA-262 section 13.2.2-7
@@ -705,6 +706,7 @@ static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
 
     // Set up the context from the function argument.
     __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
+    __ LoadConstantPoolPointer(r1);
 
     __ InitializeRootRegister();
 
@@ -843,7 +845,7 @@ void Builtins::Generate_MarkCodeAsExecutedOnce(MacroAssembler* masm) {
   __ ldm(ia_w, sp, r0.bit() | r1.bit() | fp.bit() | lr.bit());
 
   // Perform prologue operations usually performed by the young code stub.
-  __ stm(db_w, sp, r1.bit() | cp.bit() | fp.bit() | lr.bit());
+  __ PushFixedFrame(r1);

[JF, 2013/11/26 18:43:59]

Maybe I'm missing some context, but why is this needed?

[rmcilroy, 2013/11/27 17:33:56]

If code is pre-aged it will hit call this stub (rather than running it's
prologue).  Usually, the code-age stub will patch the prologue back in again,
and the stub will return to the start of the function and execute this prologue.
 In the case of the "MarkAsExecutedOnce" code stub however, the prologue code is
replaced with another marker, so we need to do the usual prologue operations
here, and jump to the point after the code-age marker.

   __ add(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
 
   // Jump to point after the code-age stub.
@@ -1026,6 +1028,7 @@ void Builtins::Generate_FunctionCall(MacroAssembler* masm) {
   { Label convert_to_object, use_global_receiver, patch_receiver;
     // Change context eagerly in case we need the global receiver.
     __ ldr(cp, FieldMemOperand(r1, JSFunction::kContextOffset));
+    __ LoadConstantPoolPointer(r1);
 
     // Do not transform the receiver for strict mode functions.
     __ ldr(r2, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
@@ -1353,7 +1356,12 @@ void Builtins::Generate_FunctionApply(MacroAssembler* masm) {
 static void EnterArgumentsAdaptorFrame(MacroAssembler* masm) {
   __ SmiTag(r0);
   __ mov(r4, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
-  __ stm(db_w, sp, r0.bit() | r1.bit() | r4.bit() | fp.bit() | lr.bit());
+  if (FLAG_enable_ool_constant_pool) {
+    __ stm(db_w, sp, r4.bit() | fp.bit() | lr.bit());
+    __ stm(db_w, sp, r0.bit() | r1.bit() | r4.bit());

[JF, 2013/11/26 18:43:59]

Can you explain why r4 is spilled twice?

[rmcilroy, 2013/11/27 17:33:56]

The second r4 is pushed where pp would usually be in the normal FixedFrame (We
need to push something here in order to have a proper FixedFrame, but didn't
need to push pp, and doing so would have not worked using stm due to the
register order).  However, due to my change to re-order the constant pool stack
slot, I can now push everything (including the pp) in a single stm instruction. 

+  } else {
+    __ stm(db_w, sp, r0.bit() | r1.bit() | r4.bit() | fp.bit() | lr.bit());
+  }
   __ add(fp, sp,
          Operand(StandardFrameConstants::kFixedFrameSizeFromFp + kPointerSize));
 }