From cd7a1c740a30fe1fcaf0756dd48a825ea2ab2337 Mon Sep 17 00:00:00 2001
From: "plind44@gmail.com"
 <plind44@gmail.com@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Wed, 13 Nov 2013 18:23:42 +0000
Subject: [PATCH] MIPS: Simplify behavior of code stubs that accept a variable
 number of stack arguments in addition to their parameters.

Port r17680 (cc0b972)

Original commit message:
Before, we'd add a special
variable to the environment with the value of a register with the
number of arguments. Now, that register just appears as a parameter to
the code stub.

BUG=
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/70163006

Patch from Balazs Kilvady <kilvadyb@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17710 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/mips/code-stubs-mips.cc  | 31 ++++++++++++++++++++++---------
 src/mips/deoptimizer-mips.cc |  2 +-
 src/mips/lithium-mips.cc     |  2 +-
 3 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index f053c79..1982c64 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -178,14 +178,21 @@ static void InitializeArrayConstructorDescriptor(
   // a0 -- number of arguments
   // a1 -- function
   // a2 -- type info cell with elements kind
-  static Register registers[] = { a1, a2 };
-  descriptor->register_param_count_ = 2;
-  if (constant_stack_parameter_count != 0) {
+  static Register registers_variable_args[] = { a1, a2, a0 };
+  static Register registers_no_args[] = { a1, a2 };
+
+  if (constant_stack_parameter_count == 0) {
+    descriptor->register_param_count_ = 2;
+    descriptor->register_params_ = registers_no_args;
+  } else {
     // stack param count needs (constructor pointer, and single argument)
+    descriptor->handler_arguments_mode_ = PASS_ARGUMENTS;
     descriptor->stack_parameter_count_ = a0;
+    descriptor->register_param_count_ = 3;
+    descriptor->register_params_ = registers_variable_args;
   }
+
   descriptor->hint_stack_parameter_count_ = constant_stack_parameter_count;
-  descriptor->register_params_ = registers;
   descriptor->function_mode_ = JS_FUNCTION_STUB_MODE;
   descriptor->deoptimization_handler_ =
       Runtime::FunctionForId(Runtime::kArrayConstructor)->entry;
@@ -199,15 +206,21 @@ static void InitializeInternalArrayConstructorDescriptor(
   // register state
   // a0 -- number of arguments
   // a1 -- constructor function
-  static Register registers[] = { a1 };
-  descriptor->register_param_count_ = 1;
+  static Register registers_variable_args[] = { a1, a0 };
+  static Register registers_no_args[] = { a1 };
 
-  if (constant_stack_parameter_count != 0) {
-    // Stack param count needs (constructor pointer, and single argument).
+  if (constant_stack_parameter_count == 0) {
+    descriptor->register_param_count_ = 1;
+    descriptor->register_params_ = registers_no_args;
+  } else {
+    // stack param count needs (constructor pointer, and single argument)
+    descriptor->handler_arguments_mode_ = PASS_ARGUMENTS;
     descriptor->stack_parameter_count_ = a0;
+    descriptor->register_param_count_ = 2;
+    descriptor->register_params_ = registers_variable_args;
   }
+
   descriptor->hint_stack_parameter_count_ = constant_stack_parameter_count;
-  descriptor->register_params_ = registers;
   descriptor->function_mode_ = JS_FUNCTION_STUB_MODE;
   descriptor->deoptimization_handler_ =
       Runtime::FunctionForId(Runtime::kInternalArrayConstructor)->entry;
diff --git a/src/mips/deoptimizer-mips.cc b/src/mips/deoptimizer-mips.cc
index d31990b..c66472f 100644
--- a/src/mips/deoptimizer-mips.cc
+++ b/src/mips/deoptimizer-mips.cc
@@ -104,7 +104,7 @@ void Deoptimizer::SetPlatformCompiledStubRegisters(
   ApiFunction function(descriptor->deoptimization_handler_);
   ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_);
   intptr_t handler = reinterpret_cast<intptr_t>(xref.address());
-  int params = descriptor->environment_length();
+  int params = descriptor->GetHandlerParameterCount();
   output_frame->SetRegister(s0.code(), params);
   output_frame->SetRegister(s1.code(), (params - 1) * kPointerSize);
   output_frame->SetRegister(s2.code(), handler);
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 70dd60d..03c64d9 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -2421,7 +2421,7 @@ LInstruction* LChunkBuilder::DoParameter(HParameter* instr) {
     CodeStubInterfaceDescriptor* descriptor =
         info()->code_stub()->GetInterfaceDescriptor(info()->isolate());
     int index = static_cast<int>(instr->index());
-    Register reg = DESCRIPTOR_GET_PARAMETER_REGISTER(descriptor, index);
+    Register reg = descriptor->GetParameterRegister(index);
     return DefineFixed(result, reg);
   }
 }
-- 
2.7.4