Remove much of the register allocation overhead from ARM. When

registers are required for calls, explicitly construct a Result with
the needed register rather than allocating it.  For returns from
calls, let the return value in r0 be implicit rather than explicitly
allocated.

Review URL: http://codereview.chromium.org/164316

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2659 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/virtual-frame-arm.cc

@@ -186,76 +186,62 @@ void VirtualFrame::PushTryHandler(HandlerType type) {
 }
 
 
-Result VirtualFrame::RawCallStub(CodeStub* stub) {
+void VirtualFrame::RawCallStub(CodeStub* stub) {
   ASSERT(cgen()->HasValidEntryRegisters());
   __ CallStub(stub);
-  Result result = cgen()->allocator()->Allocate(r0);
-  ASSERT(result.is_valid());
-  return result;
 }
 
 
-Result VirtualFrame::CallStub(CodeStub* stub, Result* arg) {
+void VirtualFrame::CallStub(CodeStub* stub, Result* arg) {
   PrepareForCall(0, 0);
   arg->Unuse();
-  return RawCallStub(stub);
+  RawCallStub(stub);
 }
 
 
-Result VirtualFrame::CallStub(CodeStub* stub, Result* arg0, Result* arg1) {
+void VirtualFrame::CallStub(CodeStub* stub, Result* arg0, Result* arg1) {
   PrepareForCall(0, 0);
   arg0->Unuse();
   arg1->Unuse();
-  return RawCallStub(stub);
+  RawCallStub(stub);
 }
 
 
-Result VirtualFrame::CallRuntime(Runtime::Function* f, int arg_count) {
+void VirtualFrame::CallRuntime(Runtime::Function* f, int arg_count) {
   PrepareForCall(arg_count, arg_count);
   ASSERT(cgen()->HasValidEntryRegisters());
   __ CallRuntime(f, arg_count);
-  Result result = cgen()->allocator()->Allocate(r0);
-  ASSERT(result.is_valid());
-  return result;
 }
 
 
-Result VirtualFrame::CallRuntime(Runtime::FunctionId id, int arg_count) {
+void VirtualFrame::CallRuntime(Runtime::FunctionId id, int arg_count) {
   PrepareForCall(arg_count, arg_count);
   ASSERT(cgen()->HasValidEntryRegisters());
   __ CallRuntime(id, arg_count);
-  Result result = cgen()->allocator()->Allocate(r0);
-  ASSERT(result.is_valid());
-  return result;
 }
 
 
-Result VirtualFrame::InvokeBuiltin(Builtins::JavaScript id,
-                                   InvokeJSFlags flags,
-                                   Result* arg_count_register,
-                                   int arg_count) {
+void VirtualFrame::InvokeBuiltin(Builtins::JavaScript id,
+                                 InvokeJSFlags flags,
+                                 Result* arg_count_register,
+                                 int arg_count) {
   ASSERT(arg_count_register->reg().is(r0));
   PrepareForCall(arg_count, arg_count);
   arg_count_register->Unuse();
   __ InvokeBuiltin(id, flags);
-  Result result = cgen()->allocator()->Allocate(r0);
-  return result;
 }
 
 
-Result VirtualFrame::RawCallCodeObject(Handle<Code> code,
+void VirtualFrame::RawCallCodeObject(Handle<Code> code,
                                        RelocInfo::Mode rmode) {
   ASSERT(cgen()->HasValidEntryRegisters());
   __ Call(code, rmode);
-  Result result = cgen()->allocator()->Allocate(r0);
-  ASSERT(result.is_valid());
-  return result;
 }
 
 
-Result VirtualFrame::CallCodeObject(Handle<Code> code,
-                                    RelocInfo::Mode rmode,
-                                    int dropped_args) {
+void VirtualFrame::CallCodeObject(Handle<Code> code,
+                                  RelocInfo::Mode rmode,
+                                  int dropped_args) {
   int spilled_args = 0;
   switch (code->kind()) {
     case Code::CALL_IC:
@@ -276,14 +262,14 @@ Result VirtualFrame::CallCodeObject(Handle<Code> code,
       break;
   }
   PrepareForCall(spilled_args, dropped_args);
-  return RawCallCodeObject(code, rmode);
+  RawCallCodeObject(code, rmode);
 }
 
 
-Result VirtualFrame::CallCodeObject(Handle<Code> code,
-                                    RelocInfo::Mode rmode,
-                                    Result* arg,
-                                    int dropped_args) {
+void VirtualFrame::CallCodeObject(Handle<Code> code,
+                                  RelocInfo::Mode rmode,
+                                  Result* arg,
+                                  int dropped_args) {
   int spilled_args = 0;
   switch (code->kind()) {
     case Code::LOAD_IC:
@@ -304,15 +290,15 @@ Result VirtualFrame::CallCodeObject(Handle<Code> code,
   }
   PrepareForCall(spilled_args, dropped_args);
   arg->Unuse();
-  return RawCallCodeObject(code, rmode);
+  RawCallCodeObject(code, rmode);
 }
 
 
-Result VirtualFrame::CallCodeObject(Handle<Code> code,
-                                    RelocInfo::Mode rmode,
-                                    Result* arg0,
-                                    Result* arg1,
-                                    int dropped_args) {
+void VirtualFrame::CallCodeObject(Handle<Code> code,
+                                  RelocInfo::Mode rmode,
+                                  Result* arg0,
+                                  Result* arg1,
+                                  int dropped_args) {
   int spilled_args = 1;
   switch (code->kind()) {
     case Code::STORE_IC:
@@ -336,7 +322,7 @@ Result VirtualFrame::CallCodeObject(Handle<Code> code,
   PrepareForCall(spilled_args, dropped_args);
   arg0->Unuse();
   arg1->Unuse();
-  return RawCallCodeObject(code, rmode);
+  RawCallCodeObject(code, rmode);
 }
 
 

src/arm/virtual-frame-arm.h

@@ -283,46 +283,46 @@ class VirtualFrame : public ZoneObject {
 
   // Call stub given the number of arguments it expects on (and
   // removes from) the stack.
-  Result CallStub(CodeStub* stub, int arg_count) {
+  void CallStub(CodeStub* stub, int arg_count) {
     PrepareForCall(arg_count, arg_count);
-    return RawCallStub(stub);
+    RawCallStub(stub);
   }
 
   // Call stub that expects its argument in r0.  The argument is given
   // as a result which must be the register r0.
-  Result CallStub(CodeStub* stub, Result* arg);
+  void CallStub(CodeStub* stub, Result* arg);
 
   // Call stub that expects its arguments in r1 and r0.  The arguments
   // are given as results which must be the appropriate registers.
-  Result CallStub(CodeStub* stub, Result* arg0, Result* arg1);
+  void CallStub(CodeStub* stub, Result* arg0, Result* arg1);
 
   // Call runtime given the number of arguments expected on (and
   // removed from) the stack.
-  Result CallRuntime(Runtime::Function* f, int arg_count);
-  Result CallRuntime(Runtime::FunctionId id, int arg_count);
+  void CallRuntime(Runtime::Function* f, int arg_count);
+  void CallRuntime(Runtime::FunctionId id, int arg_count);
 
   // Invoke builtin given the number of arguments it expects on (and
   // removes from) the stack.
-  Result InvokeBuiltin(Builtins::JavaScript id,
-                       InvokeJSFlags flag,
-                       Result* arg_count_register,
-                       int arg_count);
+  void InvokeBuiltin(Builtins::JavaScript id,
+                     InvokeJSFlags flag,
+                     Result* arg_count_register,
+                     int arg_count);
 
   // Call into an IC stub given the number of arguments it removes
   // from the stack.  Register arguments are passed as results and
   // consumed by the call.
-  Result CallCodeObject(Handle<Code> ic,
-                        RelocInfo::Mode rmode,
-                        int dropped_args);
-  Result CallCodeObject(Handle<Code> ic,
-                        RelocInfo::Mode rmode,
-                        Result* arg,
-                        int dropped_args);
-  Result CallCodeObject(Handle<Code> ic,
-                        RelocInfo::Mode rmode,
-                        Result* arg0,
-                        Result* arg1,
-                        int dropped_args);
+  void CallCodeObject(Handle<Code> ic,
+                      RelocInfo::Mode rmode,
+                      int dropped_args);
+  void CallCodeObject(Handle<Code> ic,
+                      RelocInfo::Mode rmode,
+                      Result* arg,
+                      int dropped_args);
+  void CallCodeObject(Handle<Code> ic,
+                      RelocInfo::Mode rmode,
+                      Result* arg0,
+                      Result* arg1,
+                      int dropped_args);
 
   // Drop a number of elements from the top of the expression stack.  May
   // emit code to affect the physical frame.  Does not clobber any registers
@@ -506,11 +506,11 @@ class VirtualFrame : public ZoneObject {
 
   // Call a code stub that has already been prepared for calling (via
   // PrepareForCall).
-  Result RawCallStub(CodeStub* stub);
+  void RawCallStub(CodeStub* stub);
 
   // Calls a code object which has already been prepared for calling
   // (via PrepareForCall).
-  Result RawCallCodeObject(Handle<Code> code, RelocInfo::Mode rmode);
+  void RawCallCodeObject(Handle<Code> code, RelocInfo::Mode rmode);
 
   bool Equals(VirtualFrame* other);