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

src/arm/lithium-codegen-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
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 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 127 matching lines @@
 
 #ifdef DEBUG
     if (strlen(FLAG_stop_at) > 0 &&
         info_->function()->name()->IsUtf8EqualTo(CStrVector(FLAG_stop_at))) {
       __ stop("stop_at");
     }
 #endif
 
     // r1: Callee's JS function.
     // cp: Callee's context.
+    // pp: Callee's constant pool pointer (if FLAG_enable_ool_constant_pool)
     // fp: Caller's frame pointer.
     // lr: Caller's pc.
 
     // Strict mode functions and builtins need to replace the receiver
     // with undefined when called as functions (without an explicit
     // receiver object). r5 is zero for method calls and non-zero for
     // function calls.
     if (!info_->is_classic_mode() || info_->is_native()) {
       __ cmp(r5, Operand::Zero());
       int receiver_offset = scope()->num_parameters() * kPointerSize;
       __ LoadRoot(r2, Heap::kUndefinedValueRootIndex);
       __ str(r2, MemOperand(sp, receiver_offset), ne);
     }
   }
 
   info()->set_prologue_offset(masm_->pc_offset());
   if (NeedsEagerFrame()) {

[ulan, 2013/12/18 15:06:56]

If there is no eager frame, then we load constant from the inline constant pool?

[rmcilroy, 2013/12/19 11:08:25]

We aren't going to have an inline constant pool any longer once the OOL one is
finished.  My plan is to have the asm generate movew/movev or mov/orr/orr
instruction sequences until it knows it can use the constant pool.  We might
want to have some way for lithium to know that it should output a lazy frame if
it knows that a bit of upcoming code would benefit from the constant pool
though.  Any thoughts here?

[ulan, 2013/12/19 12:54:41]

Let's see how this will affect performance. Maybe movew/movev will be
sufficient. Otherwise, we need to find some way to save/restore caller's pp.

[rmcilroy, 2013/12/19 13:31:59]

SGTM

     __ Prologue(info()->IsStub() ? BUILD_STUB_FRAME : BUILD_FUNCTION_FRAME);
     frame_is_built_ = true;
     info_->AddNoFrameRange(0, masm_->pc_offset());
+    __ LoadConstantPoolPointerRegister();

[ulan, 2013/12/18 15:06:56]

Ensure that there are no constant pool accesses before this point.

[rmcilroy, 2013/12/19 11:08:25]

Ditto.

   }
 
   // Reserve space for the stack slots needed by the code.
   int slots = GetStackSlotCount();
   if (slots > 0) {
     if (FLAG_debug_code) {
       __ sub(sp,  sp, Operand(slots * kPointerSize));
       __ push(r0);
       __ push(r1);
       __ add(r0, sp, Operand(slots *  kPointerSize));
@@ skipping 95 matching lines @@
               "-------------------- Deferred %s --------------------",
               code->instruction_index(),
               code->instr()->hydrogen_value()->id(),
               code->instr()->Mnemonic());
       __ bind(code->entry());
       if (NeedsDeferredFrame()) {
         Comment(";;; Build frame");
         ASSERT(!frame_is_built_);
         ASSERT(info()->IsStub());
         frame_is_built_ = true;
-        __ stm(db_w, sp, cp.bit() | fp.bit() | lr.bit());
+        __ PushFixedFrame();
         __ mov(scratch0(), Operand(Smi::FromInt(StackFrame::STUB)));
         __ push(scratch0());
         __ add(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
         Comment(";;; Deferred code");
       }
       code->Generate();
       if (NeedsDeferredFrame()) {
         Comment(";;; Destroy frame");
         ASSERT(frame_is_built_);
         __ pop(ip);
-        __ ldm(ia_w, sp, cp.bit() | fp.bit() | lr.bit());
+        __ PopFixedFrame();
         frame_is_built_ = false;
       }
       __ jmp(code->exit());
     }
   }
 
   // Force constant pool emission at the end of the deferred code to make
   // sure that no constant pools are emitted after.
   masm()->CheckConstPool(true, false);
 
@@ skipping 30 matching lines @@
     } else {
       Comment(";;; jump table entry %d: deoptimization bailout %d.", i, id);
     }
     if (deopt_jump_table_[i].needs_frame) {
       ASSERT(!info()->saves_caller_doubles());
       __ mov(ip, Operand(ExternalReference::ForDeoptEntry(entry)));
       if (needs_frame.is_bound()) {
         __ b(&needs_frame);
       } else {
         __ bind(&needs_frame);
-        __ stm(db_w, sp, cp.bit() | fp.bit() | lr.bit());
+        __ PushFixedFrame();
         // This variant of deopt can only be used with stubs. Since we don't
         // have a function pointer to install in the stack frame that we're
         // building, install a special marker there instead.
         ASSERT(info()->IsStub());
         __ mov(scratch0(), Operand(Smi::FromInt(StackFrame::STUB)));
         __ push(scratch0());
         __ add(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
         __ mov(lr, Operand(pc), LeaveCC, al);
         __ mov(pc, ip);
       }
@@ skipping 2595 matching lines @@
     // safe to write to the context register.
     __ push(r0);
     __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
     __ CallRuntime(Runtime::kTraceExit, 1);
   }
   if (info()->saves_caller_doubles()) {
     RestoreCallerDoubles();
   }
   int no_frame_start = -1;
   if (NeedsEagerFrame()) {
-    __ mov(sp, fp);
-    no_frame_start = masm_->pc_offset();
-    __ ldm(ia_w, sp, fp.bit() | lr.bit());
+    no_frame_start = masm_->LeaveFrame(StackFrame::JAVA_SCRIPT);
   }
   if (instr->has_constant_parameter_count()) {
     int parameter_count = ToInteger32(instr->constant_parameter_count());
     int32_t sp_delta = (parameter_count + 1) * kPointerSize;
     if (sp_delta != 0) {
       __ add(sp, sp, Operand(sp_delta));
     }
   } else {
     Register reg = ToRegister(instr->parameter_count());
     // The argument count parameter is a smi
@@ skipping 2902 matching lines @@
   __ sub(scratch, result, Operand::PointerOffsetFromSmiKey(index));
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal