Landing for Rodolph Perfetta.

Allow compareStub on ARM to take register in reverse order optionally.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/2850046/show

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5059 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/full-codegen-arm.cc

@@ -822,8 +822,7 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     // the smi vs. smi case to be handled before it is called.
     Label slow_case;
     __ ldr(r1, MemOperand(sp, 0));  // Switch value.
-    __ mov(r2, r1);
-    __ orr(r2, r2, r0);
+    __ orr(r2, r1, r0);
     __ tst(r2, Operand(kSmiTagMask));
     __ b(ne, &slow_case);
     __ cmp(r1, r0);
@@ -832,9 +831,9 @@ void FullCodeGenerator::VisitSwitchStatement(SwitchStatement* stmt) {
     __ b(clause->body_target()->entry_label());
 
     __ bind(&slow_case);
-    CompareStub stub(eq, true);
+    CompareStub stub(eq, true, kBothCouldBeNaN, true, r1, r0);
     __ CallStub(&stub);
-    __ tst(r0, r0);
+    __ cmp(r0, Operand(0));
     __ b(ne, &next_test);
     __ Drop(1);  // Switch value is no longer needed.
     __ b(clause->body_target()->entry_label());
@@ -3088,7 +3087,7 @@ void FullCodeGenerator::VisitCompareOperation(CompareOperation* expr) {
       __ jmp(if_false);
 
       __ bind(&slow_case);
-      CompareStub stub(cc, strict);
+      CompareStub stub(cc, strict, kBothCouldBeNaN, true, r1, r0);
       __ CallStub(&stub);
       __ cmp(r0, Operand(0));
       __ b(cc, if_true);

src/codegen.h

@@ -461,11 +461,15 @@ class CompareStub: public CodeStub {
   CompareStub(Condition cc,
               bool strict,
               NaNInformation nan_info = kBothCouldBeNaN,
-              bool include_number_compare = true) :
+              bool include_number_compare = true,
+              Register lhs = no_reg,
+              Register rhs = no_reg) :
       cc_(cc),
       strict_(strict),
       never_nan_nan_(nan_info == kCantBothBeNaN),
       include_number_compare_(include_number_compare),
+      lhs_(lhs),
+      rhs_(rhs),
       name_(NULL) { }
 
   void Generate(MacroAssembler* masm);
@@ -483,12 +487,19 @@ class CompareStub: public CodeStub {
   // comparison code is used when the number comparison has been inlined, and
   // the stub will be called if one of the operands is not a number.
   bool include_number_compare_;
-
-  // Encoding of the minor key CCCCCCCCCCCCCCNS.
+  // Register holding the left hand side of the comparison if the stub gives
+  // a choice, no_reg otherwise.
+  Register lhs_;
+  // Register holding the right hand side of the comparison if the stub gives
+  // a choice, no_reg otherwise.
+  Register rhs_;
+
+  // Encoding of the minor key CCCCCCCCCCCCRCNS.
   class StrictField: public BitField<bool, 0, 1> {};
   class NeverNanNanField: public BitField<bool, 1, 1> {};
   class IncludeNumberCompareField: public BitField<bool, 2, 1> {};
-  class ConditionField: public BitField<int, 3, 13> {};
+  class RegisterField: public BitField<bool, 3, 1> {};
+  class ConditionField: public BitField<int, 4, 12> {};
 
   Major MajorKey() { return Compare; }
 
@@ -507,11 +518,17 @@ class CompareStub: public CodeStub {
 #ifdef DEBUG
   void Print() {
     PrintF("CompareStub (cc %d), (strict %s), "
-           "(never_nan_nan %s), (number_compare %s)\n",
+           "(never_nan_nan %s), (number_compare %s) ",
            static_cast<int>(cc_),
            strict_ ? "true" : "false",
            never_nan_nan_ ? "true" : "false",
            include_number_compare_ ? "included" : "not included");
+
+    if (!lhs_.is(no_reg) && !rhs_.is(no_reg)) {
+      PrintF("(lhs r%d), (rhs r%d)\n", lhs_.code(), rhs_.code());
+    } else {
+      PrintF("\n");
+    }
   }
 #endif
 };

src/ia32/codegen-ia32.cc

@@ -11635,6 +11635,8 @@ static int NegativeComparisonResult(Condition cc) {
 
 
 void CompareStub::Generate(MacroAssembler* masm) {
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
+
   Label check_unequal_objects, done;
 
   // NOTICE! This code is only reached after a smi-fast-case check, so
@@ -12528,8 +12530,10 @@ int CompareStub::MinorKey() {
   // Encode the three parameters in a unique 16 bit value. To avoid duplicate
   // stubs the never NaN NaN condition is only taken into account if the
   // condition is equals.
-  ASSERT(static_cast<unsigned>(cc_) < (1 << 13));
+  ASSERT(static_cast<unsigned>(cc_) < (1 << 12));
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
   return ConditionField::encode(static_cast<unsigned>(cc_))
+         | RegisterField::encode(false)   // lhs_ and rhs_ are not used
          | StrictField::encode(strict_)
          | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false)
          | IncludeNumberCompareField::encode(include_number_compare_);
@@ -12539,6 +12543,8 @@ int CompareStub::MinorKey() {
 // Unfortunately you have to run without snapshots to see most of these
 // names in the profile since most compare stubs end up in the snapshot.
 const char* CompareStub::GetName() {
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
+
   if (name_ != NULL) return name_;
   const int kMaxNameLength = 100;
   name_ = Bootstrapper::AllocateAutoDeletedArray(kMaxNameLength);

src/x64/codegen-x64.cc

@@ -10094,6 +10094,8 @@ static int NegativeComparisonResult(Condition cc) {
 
 
 void CompareStub::Generate(MacroAssembler* masm) {
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
+
   Label check_unequal_objects, done;
   // The compare stub returns a positive, negative, or zero 64-bit integer
   // value in rax, corresponding to result of comparing the two inputs.
@@ -10942,8 +10944,10 @@ int CompareStub::MinorKey() {
   // Encode the three parameters in a unique 16 bit value. To avoid duplicate
   // stubs the never NaN NaN condition is only taken into account if the
   // condition is equals.
-  ASSERT(static_cast<unsigned>(cc_) < (1 << 13));
+  ASSERT(static_cast<unsigned>(cc_) < (1 << 12));
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
   return ConditionField::encode(static_cast<unsigned>(cc_))
+         | RegisterField::encode(false)    // lhs_ and rhs_ are not used
          | StrictField::encode(strict_)
          | NeverNanNanField::encode(cc_ == equal ? never_nan_nan_ : false)
          | IncludeNumberCompareField::encode(include_number_compare_);
@@ -10953,6 +10957,8 @@ int CompareStub::MinorKey() {
 // Unfortunately you have to run without snapshots to see most of these
 // names in the profile since most compare stubs end up in the snapshot.
 const char* CompareStub::GetName() {
+  ASSERT(lhs_.is(no_reg) && rhs_.is(no_reg));
+
   if (name_ != NULL) return name_;
   const int kMaxNameLength = 100;
   name_ = Bootstrapper::AllocateAutoDeletedArray(kMaxNameLength);