VM-codegen: Clean up the way we emit code for comparison instructions.

runtime/vm/intermediate_language_mips.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/compiler.h"
@@ skipping 160 matching lines @@
     intptr_t temp = true_value;
     true_value = false_value;
     false_value = temp;
     swapped = true;
   }
 
   // Initialize result with the true value.
   __ LoadImmediate(result, Smi::RawValue(true_value));
 
   // Emit comparison code. This must not overwrite the result register.
+  // IfThenElseInstr::Supports() should prevent EmitComparisonCode from using
+  // the labels or returning an invalid condition.
   BranchLabels labels = {NULL, NULL, NULL};  // Emit branch-free code.
   Condition true_condition = comparison()->EmitComparisonCode(compiler, labels);
+  ASSERT(true_condition.IsValid());
   if (swapped) {
     true_condition = NegateCondition(true_condition);
   }
 
   // Evaluate condition and provide result in CMPRES1.
   Register left = true_condition.left();
   Register right = true_condition.right();
   bool zero_is_false = true;  // Zero in CMPRES1 indicates a false condition.
   switch (true_condition.rel_op()) {
     case AL:
@@ skipping 581 matching lines @@
     return EmitSmiComparisonOp(compiler, *locs(), kind());
   } else if (operation_cid() == kMintCid) {
     return EmitUnboxedMintEqualityOp(compiler, *locs(), kind(), labels);
   } else {
     ASSERT(operation_cid() == kDoubleCid);
     return EmitDoubleComparisonOp(compiler, *locs(), kind(), labels);
   }
 }
 
 
-void EqualityCompareInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  ASSERT((kind() == Token::kNE) || (kind() == Token::kEQ));
-  __ Comment("EqualityCompareInstr");
-
+void ComparisonInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Label is_true, is_false;
   BranchLabels labels = {&is_true, &is_false, &is_false};
   Condition true_condition = EmitComparisonCode(compiler, labels);
-  EmitBranchOnCondition(compiler, true_condition, labels);
+  if (true_condition.IsValid()) {
+    EmitBranchOnCondition(compiler, true_condition, labels);
+  }
 
-  Register result = locs()->out(0).reg();
+  Register result = this->locs()->out(0).reg();
   Label done;
   __ Bind(&is_false);
   __ LoadObject(result, Bool::False());
   __ b(&done);
   __ Bind(&is_true);
   __ LoadObject(result, Bool::True());
   __ Bind(&done);
 }
 
 
-void EqualityCompareInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                          BranchInstr* branch) {
-  __ Comment("EqualityCompareInstr::EmitBranchCode");
-  ASSERT((kind() == Token::kNE) || (kind() == Token::kEQ));
-
+void ComparisonInstr::EmitBranchCode(FlowGraphCompiler* compiler,
+                                     BranchInstr* branch) {
   BranchLabels labels = compiler->CreateBranchLabels(branch);
   Condition true_condition = EmitComparisonCode(compiler, labels);
-  EmitBranchOnCondition(compiler, true_condition, labels);
+  if (true_condition.IsValid()) {
+    EmitBranchOnCondition(compiler, true_condition, labels);
+  }
 }
 
 
 LocationSummary* TestSmiInstr::MakeLocationSummary(Zone* zone, bool opt) const {
   const intptr_t kNumInputs = 2;
   const intptr_t kNumTemps = 0;
   LocationSummary* locs = new (zone)
       LocationSummary(zone, kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_in(0, Location::RequiresRegister());
   // Only one input can be a constant operand. The case of two constant
@@ skipping 11 matching lines @@
     ASSERT(right.constant().IsSmi());
     const int32_t imm = reinterpret_cast<int32_t>(right.constant().raw());
     __ AndImmediate(CMPRES1, left, imm);
   } else {
     __ and_(CMPRES1, left, right.reg());
   }
   return Condition(CMPRES1, ZR, (kind() == Token::kNE) ? NE : EQ);
 }
 
 
-void TestSmiInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  // Never emitted outside of the BranchInstr.
-  UNREACHABLE();
-}
-
-
-void TestSmiInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                  BranchInstr* branch) {
-  BranchLabels labels = compiler->CreateBranchLabels(branch);
-  Condition true_condition = EmitComparisonCode(compiler, labels);
-  EmitBranchOnCondition(compiler, true_condition, labels);
-}
-
-
 LocationSummary* TestCidsInstr::MakeLocationSummary(Zone* zone,
                                                     bool opt) const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 1;
   LocationSummary* locs = new (zone)
       LocationSummary(zone, kNumInputs, kNumTemps, LocationSummary::kNoCall);
   locs->set_in(0, Location::RequiresRegister());
   locs->set_temp(0, Location::RequiresRegister());
   locs->set_out(0, Location::RequiresRegister());
   return locs;
@@ skipping 32 matching lines @@
     // If the cid is not in the list, jump to the opposite label from the cids
     // that are in the list.  These must be all the same (see asserts in the
     // constructor).
     Label* target = result ? labels.false_label : labels.true_label;
     if (target != labels.fall_through) {
       __ b(target);
     }
   } else {
     __ b(deopt);
   }
-  // Dummy result as the last instruction is a jump or fall through.
-  return Condition(CMPRES1, ZR, AL);
+  // Dummy result as this method already did the jump, there's no need
+  // for the caller to branch on a condition.
+  return Condition(ZR, ZR, INVALID_RELATION);
 }
 
 
-void TestCidsInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                   BranchInstr* branch) {
-  BranchLabels labels = compiler->CreateBranchLabels(branch);
-  EmitComparisonCode(compiler, labels);
-}
-
-
-void TestCidsInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  Register result_reg = locs()->out(0).reg();
-  Label is_true, is_false, done;
-  BranchLabels labels = {&is_true, &is_false, &is_false};
-  EmitComparisonCode(compiler, labels);
-  __ Bind(&is_false);
-  __ LoadObject(result_reg, Bool::False());
-  __ b(&done);
-  __ Bind(&is_true);
-  __ LoadObject(result_reg, Bool::True());
-  __ Bind(&done);
-}
-
-
 LocationSummary* RelationalOpInstr::MakeLocationSummary(Zone* zone,
                                                         bool opt) const {
   const intptr_t kNumInputs = 2;
   const intptr_t kNumTemps = 0;
   if (operation_cid() == kMintCid) {
     const intptr_t kNumTemps = 0;
     LocationSummary* locs = new (zone)
         LocationSummary(zone, kNumInputs, kNumTemps, LocationSummary::kNoCall);
     locs->set_in(0, Location::Pair(Location::RequiresRegister(),
                                    Location::RequiresRegister()));
@@ skipping 30 matching lines @@
     return EmitSmiComparisonOp(compiler, *locs(), kind());
   } else if (operation_cid() == kMintCid) {
     return EmitUnboxedMintComparisonOp(compiler, *locs(), kind(), labels);
   } else {
     ASSERT(operation_cid() == kDoubleCid);
     return EmitDoubleComparisonOp(compiler, *locs(), kind(), labels);
   }
 }
 
 
-void RelationalOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  __ Comment("RelationalOpInstr");
-
-  Label is_true, is_false;
-  BranchLabels labels = {&is_true, &is_false, &is_false};
-  Condition true_condition = EmitComparisonCode(compiler, labels);
-  EmitBranchOnCondition(compiler, true_condition, labels);
-
-  Register result = locs()->out(0).reg();
-  Label done;
-  __ Bind(&is_false);
-  __ LoadObject(result, Bool::False());
-  __ b(&done);
-  __ Bind(&is_true);
-  __ LoadObject(result, Bool::True());
-  __ Bind(&done);
-}
-
-
-void RelationalOpInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                       BranchInstr* branch) {
-  __ Comment("RelationalOpInstr");
-
-  BranchLabels labels = compiler->CreateBranchLabels(branch);
-  Condition true_condition = EmitComparisonCode(compiler, labels);
-  EmitBranchOnCondition(compiler, true_condition, labels);
-}
-
-
 LocationSummary* NativeCallInstr::MakeLocationSummary(Zone* zone,
                                                       bool opt) const {
   return MakeCallSummary(zone);
 }
 
 
 void NativeCallInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   SetupNative();
   __ Comment("NativeCallInstr");
   Register result = locs()->out(0).reg();
@@ skipping 2216 matching lines @@
 
 void CheckedSmiComparisonInstr::EmitBranchCode(FlowGraphCompiler* compiler,
                                                BranchInstr* branch) {
   BranchLabels labels = compiler->CreateBranchLabels(branch);
   CheckedSmiComparisonSlowPath* slow_path = new CheckedSmiComparisonSlowPath(
       this, compiler->CurrentTryIndex(), labels,
       /* merged = */ true);
   compiler->AddSlowPathCode(slow_path);
   EMIT_SMI_CHECK;
   Condition true_condition = EmitComparisonCode(compiler, labels);
+  ASSERT(true_condition.IsValid());
   EmitBranchOnCondition(compiler, true_condition, labels);
   __ Bind(slow_path->exit_label());
 }
 
 
 void CheckedSmiComparisonInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Label true_label, false_label, done;
   BranchLabels labels = {&true_label, &false_label, &false_label};
   CheckedSmiComparisonSlowPath* slow_path = new CheckedSmiComparisonSlowPath(
       this, compiler->CurrentTryIndex(), labels,
       /* merged = */ false);
   compiler->AddSlowPathCode(slow_path);
   EMIT_SMI_CHECK;
   Condition true_condition = EmitComparisonCode(compiler, labels);
+  ASSERT(true_condition.IsValid());
   EmitBranchOnCondition(compiler, true_condition, labels);
   Register result = locs()->out(0).reg();
   __ Bind(&false_label);
   __ LoadObject(result, Bool::False());
   __ b(&done);
   __ Bind(&true_label);
   __ LoadObject(result, Bool::True());
   __ Bind(&done);
   __ Bind(slow_path->exit_label());
 }
@@ skipping 694 matching lines @@
         __ bc1t(labels.true_label);
       }
     } else {
       if (is_negated) {
         __ bc1t(labels.false_label);
       } else {
         __ bc1f(labels.false_label);
       }
       __ b(labels.true_label);
     }
-    return Condition();  // Unused.
+    return Condition(ZR, ZR, INVALID_RELATION);  // Unused.
   } else {
     ASSERT(op_kind() == MethodRecognizer::kDouble_getIsInfinite);
     __ mfc1(CMPRES1, EvenFRegisterOf(value));
     // If the low word isn't zero, then it isn't infinity.
     __ bne(CMPRES1, ZR, is_negated ? labels.true_label : labels.false_label);
     __ mfc1(CMPRES1, OddFRegisterOf(value));
     // Mask off the sign bit.
     __ AndImmediate(CMPRES1, CMPRES1, 0x7FFFFFFF);
     // Compare with +infinity.
     __ LoadImmediate(CMPRES2, 0x7FF00000);
     return Condition(CMPRES1, CMPRES2, is_negated ? NE : EQ);
   }
 }
 
-void DoubleTestOpInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                       BranchInstr* branch) {
-  ASSERT(compiler->is_optimizing());
-  BranchLabels labels = compiler->CreateBranchLabels(branch);
-  Condition true_condition = EmitComparisonCode(compiler, labels);
-  // Branches for isNaN are emitted in EmitComparisonCode already.
-  if (op_kind() == MethodRecognizer::kDouble_getIsInfinite) {
-    EmitBranchOnCondition(compiler, true_condition, labels);
-  }
-}
-
-
-void DoubleTestOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  Label is_true, is_false;
-  BranchLabels labels = {&is_true, &is_false, &is_false};
-  Condition true_condition = EmitComparisonCode(compiler, labels);
-  // Branches for isNaN are emitted in EmitComparisonCode already.
-  if (op_kind() == MethodRecognizer::kDouble_getIsInfinite) {
-    EmitBranchOnCondition(compiler, true_condition, labels);
-  }
-  const Register result = locs()->out(0).reg();
-  Label done;
-  __ Comment("return bool");
-  __ Bind(&is_false);
-  __ LoadObject(result, Bool::False());
-  __ b(&done);
-  __ Bind(&is_true);
-  __ LoadObject(result, Bool::True());
-  __ Bind(&done);
-}
-
-
 LocationSummary* BinaryFloat32x4OpInstr::MakeLocationSummary(Zone* zone,
                                                              bool opt) const {
   UNIMPLEMENTED();
   return NULL;
 }
 
 
 void BinaryFloat32x4OpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   UNIMPLEMENTED();
 }
@@ skipping 1944 matching lines @@
         left.reg(), right.reg(), needs_number_check(), token_pos(), deopt_id_);
   }
   if (kind() != Token::kEQ_STRICT) {
     ASSERT(kind() == Token::kNE_STRICT);
     true_condition = NegateCondition(true_condition);
   }
   return true_condition;
 }
 
 
-void StrictCompareInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  __ Comment("StrictCompareInstr");
-  ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
-
-  Label is_true, is_false;
-  BranchLabels labels = {&is_true, &is_false, &is_false};
-  Condition true_condition = EmitComparisonCode(compiler, labels);
-  EmitBranchOnCondition(compiler, true_condition, labels);
-
-  Register result = locs()->out(0).reg();
-  Label done;
-  __ Bind(&is_false);
-  __ LoadObject(result, Bool::False());
-  __ b(&done);
-  __ Bind(&is_true);
-  __ LoadObject(result, Bool::True());
-  __ Bind(&done);
-}
-
-
-void StrictCompareInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                        BranchInstr* branch) {
-  __ Comment("StrictCompareInstr::EmitBranchCode");
-  ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
-
-  BranchLabels labels = compiler->CreateBranchLabels(branch);
-  Condition true_condition = EmitComparisonCode(compiler, labels);
-  EmitBranchOnCondition(compiler, true_condition, labels);
-}
-
-
 LocationSummary* BooleanNegateInstr::MakeLocationSummary(Zone* zone,
                                                          bool opt) const {
   return LocationSummary::Make(zone, 1, Location::RequiresRegister(),
                                LocationSummary::kNoCall);
 }
 
 
 void BooleanNegateInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register value = locs()->in(0).reg();
   Register result = locs()->out(0).reg();
@@ skipping 54 matching lines @@
   compiler->GenerateRuntimeCall(TokenPosition::kNoSource, deopt_id(),
                                 kGrowRegExpStackRuntimeEntry, 1, locs());
   __ lw(result, Address(SP, 1 * kWordSize));
   __ addiu(SP, SP, Immediate(2 * kWordSize));
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS