Add dynamic stack frame alignment to optimized functions with untagged doubles on the stack.

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // 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 60 matching lines @@
   status_ = GENERATING;
   CpuFeatures::Scope scope(SSE2);
 
   CodeStub::GenerateFPStubs();
 
   // Open a frame scope to indicate that there is a frame on the stack.  The
   // MANUAL indicates that the scope shouldn't actually generate code to set up
   // the frame (that is done in GeneratePrologue).
   FrameScope frame_scope(masm_, StackFrame::MANUAL);
 
+  set_dynamic_frame_alignment(chunk()->num_double_slots() > 2 ||
+                              info()->osr_ast_id() != AstNode::kNoNumber);
+
   return GeneratePrologue() &&
       GenerateBody() &&
       GenerateDeferredCode() &&
       GenerateSafepointTable();
 }
 
 
 void LCodeGen::FinishCode(Handle<Code> code) {
   ASSERT(is_done());
   code->set_stack_slots(GetStackSlotCount());
@@ skipping 54 matching lines @@
     Label ok;
     __ test(ecx, Operand(ecx));
     __ j(zero, &ok, Label::kNear);
     // +1 for return address.
     int receiver_offset = (scope()->num_parameters() + 1) * kPointerSize;
     __ mov(Operand(esp, receiver_offset),
            Immediate(isolate()->factory()->undefined_value()));
     __ bind(&ok);
   }
 
+  if (dynamic_frame_alignment()) {
+    Label do_not_pad, align_loop;
+    __ mov(ebx, esp);

[Kevin Millikin (Chromium), 2011/09/23 09:38:49]

Can you test(esp, 4)?

[William Hesse, 2011/09/23 12:50:11]

Done.

+    __ and_(ebx, Immediate(0x4));

[Kevin Millikin (Chromium), 2011/09/23 09:38:49]

Is this better (kDoubleSize - 1) or (kDoubleSize >> 1) or some other named
constant?

[William Hesse, 2011/09/23 12:50:11]

Done.

+    __ j(zero, &do_not_pad, Label::kNear);
+    __ mov(ebx, esp);

[Kevin Millikin (Chromium), 2011/09/23 09:38:49]

The last move after the loop might be slightly more obvious if you make ebx be
the address you're copying to, rather than from.

[William Hesse, 2011/09/23 12:50:11]

Done.

+    __ push(Immediate(0));
+    __ mov(ecx, Immediate(scope()->num_parameters() + 2));

[Kevin Millikin (Chromium), 2011/09/23 09:38:49]

Comment should say 2 is receiver + return address.

[William Hesse, 2011/09/23 12:50:11]

Done.

+
+    __ bind(&align_loop);
+    __ mov(eax, Operand(ebx, 0));
+    __ mov(Operand(ebx, -1 * kPointerSize), eax);
+    __ add(Operand(ebx), Immediate(kPointerSize));
+    __ dec(ecx);
+    __ j(not_zero, &align_loop, Label::kNear);
+    __ mov(Operand(ebx, -1 * kPointerSize),
+           Immediate(isolate()->factory()->frame_alignment_marker()));
+
+    __ bind(&do_not_pad);
+  }
+
   __ push(ebp);  // Caller's frame pointer.
   __ mov(ebp, esp);
   __ push(esi);  // Callee's context.
   __ push(edi);  // Callee's JS function.
 
   // Reserve space for the stack slots needed by the code.
   int slots = GetStackSlotCount();
   if (slots > 0) {
     if (FLAG_debug_code) {
       __ mov(Operand(eax), Immediate(slots));
@@ skipping 1844 matching lines @@
 void LCodeGen::DoReturn(LReturn* instr) {
   if (FLAG_trace) {
     // Preserve the return value on the stack and rely on the runtime call
     // to return the value in the same register.  We're leaving the code
     // managed by the register allocator and tearing down the frame, it's
     // safe to write to the context register.
     __ push(eax);
     __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
     __ CallRuntime(Runtime::kTraceExit, 1);
   }
+  if (dynamic_frame_alignment()) {
+    Label aligned;
+    __ cmp(Operand(ebp, (GetParameterCount() + 3) * kPointerSize),

[Kevin Millikin (Chromium), 2011/09/23 09:38:49]

3 ~ caller's fp, return address, receiver.

[William Hesse, 2011/09/23 12:50:11]

Done.

+           Immediate(factory()->frame_alignment_marker()));
+    __ j(not_equal, &aligned);
+    __ mov(esp, ebp);
+    __ pop(ebp);

[Kevin Millikin (Chromium), 2011/09/23 09:38:49]

Slightly more compact is:

__ mov(esp, ebp);
__ pop(ebp);
__ cmp(Operand(esp, (param_count + 2) * kPointerSize), marker);
__ j(not_equal, &aligned);
__ Ret(parameter_count + 2);
__ bind(&aligned);
__ Ret(parameter_count + 1);

[William Hesse, 2011/09/23 12:50:11]

Done.

+    __ Ret((GetParameterCount() + 2) * kPointerSize, ecx);
+    __ bind(&aligned);
+  }
   __ mov(esp, ebp);
   __ pop(ebp);
   __ Ret((GetParameterCount() + 1) * kPointerSize, ecx);
 }
 
 
 void LCodeGen::DoLoadGlobalCell(LLoadGlobalCell* instr) {
   Register result = ToRegister(instr->result());
   __ mov(result, Operand::Cell(instr->hydrogen()->cell()));
   if (instr->hydrogen()->check_hole_value()) {
@@ skipping 2392 matching lines @@
                                          env->deoptimization_index());
   __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION, safepoint_generator);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32