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

src/arm/full-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:
 //
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 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
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@@ skipping 101 matching lines @@
 
 
 // Generate code for a JS function.  On entry to the function the receiver
 // and arguments have been pushed on the stack left to right.  The actual
 // argument count matches the formal parameter count expected by the
 // function.
 //
 // The live registers are:
 //   o r1: the JS function object being called (i.e., ourselves)
 //   o cp: our context
+//   o pp: our caller's constant pool pointer (if FLAG_enable_ool_constant_pool)
 //   o fp: our caller's frame pointer
 //   o sp: stack pointer
 //   o lr: return address
 //
 // The function builds a JS frame.  Please see JavaScriptFrameConstants in
 // frames-arm.h for its layout.
 void FullCodeGenerator::Generate() {
   CompilationInfo* info = info_;
   handler_table_ =
       isolate()->factory()->NewFixedArray(function()->handler_count(), TENURED);
@@ skipping 291 matching lines @@
 
 #ifdef DEBUG
     // Add a label for checking the size of the code used for returning.
     Label check_exit_codesize;
     masm_->bind(&check_exit_codesize);
 #endif
     // Make sure that the constant pool is not emitted inside of the return
     // sequence.
     { Assembler::BlockConstPoolScope block_const_pool(masm_);
       // Here we use masm_-> instead of the __ macro to avoid the code coverage
       // tool from instrumenting as we rely on the code size here.

[JF, 2013/12/13 17:33:39]

This comment seems to say __ shouldn't be used at least for a certain scope,
could you add a comment where that scope banning __ ends?

[rmcilroy, 2013/12/16 14:56:21]

I missed this comment.  From talking with the the original author (Soren) who
added this comment, he said he didn't think the code coverage tool was used any
longer.  

Daniel: Do you know if this is the case?

I've changing all to masm()-> to __ on this assumption.

[Sven Panne, 2013/12/17 07:23:58]

I can't find any place where GENERATED_CODE_COVERAGE is #defined, so I guess
that it is untested for several years, which in turn implies that it is broken
with 99.99% probability, anyway. :-) So my gut feeling is that we should simply
remove this stuff.

[rmcilroy, 2013/12/18 13:23:08]

Great, thanks Sven. Done.

       int32_t sp_delta = (info_->scope()->num_parameters() + 1) * kPointerSize;
       CodeGenerator::RecordPositions(masm_, function()->end_position() - 1);
       // TODO(svenpanne) The code below is sometimes 4 words, sometimes 5!
       PredictableCodeSizeScope predictable(masm_, -1);
       __ RecordJSReturn();
-      masm_->mov(sp, fp);
-      int no_frame_start = masm_->pc_offset();
-      masm_->ldm(ia_w, sp, fp.bit() | lr.bit());
-      masm_->add(sp, sp, Operand(sp_delta));
-      masm_->Jump(lr);
+      int no_frame_start = masm_->LeaveFrame(StackFrame::JAVA_SCRIPT);
+      __ add(sp, sp, Operand(sp_delta));
+      __ Jump(lr);
       info_->AddNoFrameRange(no_frame_start, masm_->pc_offset());
     }
 
 #ifdef DEBUG
     // Check that the size of the code used for returning is large enough
     // for the debugger's requirements.
     ASSERT(Assembler::kJSReturnSequenceInstructions <=
            masm_->InstructionsGeneratedSince(&check_exit_codesize));
 #endif
   }
@@ skipping 1708 matching lines @@
 
   // Enter a new JavaScript frame, and initialize its slots as they were when
   // the generator was suspended.
   Label resume_frame;
   __ bind(&push_frame);
   __ bl(&resume_frame);
   __ jmp(&done);
   __ bind(&resume_frame);
   // lr = return address.
   // fp = caller's frame pointer.
+  // pp = caller's constant pool (if FLAG_enable_ool_constant_pool),
   // cp = callee's context,
   // r4 = callee's JS function.
-  __ Push(lr, fp, cp, r4);
+  __ PushFixedFrame(r4);
   // Adjust FP to point to saved FP.
-  __ add(fp, sp, Operand(2 * kPointerSize));
+  __ add(fp, sp, Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
 
   // Load the operand stack size.
   __ ldr(r3, FieldMemOperand(r1, JSGeneratorObject::kOperandStackOffset));
   __ ldr(r3, FieldMemOperand(r3, FixedArray::kLengthOffset));
   __ SmiUntag(r3);
 
   // If we are sending a value and there is no operand stack, we can jump back
   // in directly.
   if (resume_mode == JSGeneratorObject::NEXT) {
     Label slow_resume;
@@ skipping 2742 matching lines @@
   ASSERT(Memory::uint32_at(interrupt_address_pointer) ==
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM