A64: Improve the deoptimization helpers to generate fewer instructions.

src/a64/lithium-codegen-a64.cc

Index: src/a64/lithium-codegen-a64.cc
diff --git a/src/a64/lithium-codegen-a64.cc b/src/a64/lithium-codegen-a64.cc
index 033a439513672589c0727811ac25f47fd4d984a6..703399213cca10f6f72888c01d36618110ee9971 100644
--- a/src/a64/lithium-codegen-a64.cc
+++ b/src/a64/lithium-codegen-a64.cc
@@ -1005,8 +1005,11 @@ Deoptimizer::BailoutType LCodeGen::DeoptimizeHeader(
 }
 
 
-void LCodeGen::Deoptimize(LEnvironment* environment,
-                          Deoptimizer::BailoutType bailout_type) {
+void LCodeGen::DeoptimizeBranch(LEnvironment* environment,
+                                Deoptimizer::BailoutType bailout_type,
+                                BranchType branch_type,
+                                Register reg,
+                                int bit) {

[jochen (gone - plz use gerrit), 2014/02/19 16:22:47]

it should be possible to merge DeoptimizeHeader into this method now, no?

[Alexandre Rames, 2014/02/19 17:20:29]

Done.

   ASSERT(environment->HasBeenRegistered());
   ASSERT(info()->IsOptimizing() || info()->IsStub());
   int id = environment->deoptimization_index();
@@ -1014,13 +1017,19 @@ void LCodeGen::Deoptimize(LEnvironment* environment,
       Deoptimizer::GetDeoptimizationEntry(isolate(), id, bailout_type);
 
   if (info()->ShouldTrapOnDeopt()) {
+    Label dont_trap;
+    __ B(&dont_trap, InvertBranchType(branch_type), reg, bit);
     __ Debug("trap_on_deopt", __LINE__, BREAK);
+    __ Bind(&dont_trap);
   }
 
   ASSERT(info()->IsStub() || frame_is_built_);
   // Go through jump table if we need to build frame, or restore caller doubles.
   if (frame_is_built_ && !info()->saves_caller_doubles()) {
+    Label dont_deopt;
+    __ B(&dont_deopt, InvertBranchType(branch_type), reg, bit);
     __ Call(entry, RelocInfo::RUNTIME_ENTRY);
+    __ Bind(&dont_deopt);
   } else {
     // We often have several deopts to the same entry, reuse the last
     // jump entry if this is the case.
@@ -1033,82 +1042,63 @@ void LCodeGen::Deoptimize(LEnvironment* environment,
                                               !frame_is_built_);
       deopt_jump_table_.Add(table_entry, zone());
     }
-    __ B(&deopt_jump_table_.last().label);
+    __ B(&deopt_jump_table_.last().label,
+         branch_type, reg, bit);
   }
 }
 
 
+void LCodeGen::Deoptimize(LEnvironment* environment,
+                          Deoptimizer::BailoutType bailout_type) {
+  DeoptimizeBranch(environment, bailout_type, always);
+}
+
+
 void LCodeGen::Deoptimize(LEnvironment* environment) {
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  Deoptimize(environment, bailout_type);
+  DeoptimizeBranch(environment, always);
 }
 
 
 void LCodeGen::DeoptimizeIf(Condition cond, LEnvironment* environment) {
-  Label dont_deopt;
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  __ B(InvertCondition(cond), &dont_deopt);
-  Deoptimize(environment, bailout_type);
-  __ Bind(&dont_deopt);
+  DeoptimizeBranch(environment, static_cast<BranchType>(cond));
 }
 
 
 void LCodeGen::DeoptimizeIfZero(Register rt, LEnvironment* environment) {
-  Label dont_deopt;
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  __ Cbnz(rt, &dont_deopt);
-  Deoptimize(environment, bailout_type);
-  __ Bind(&dont_deopt);
+  DeoptimizeBranch(environment, reg_zero, rt);
 }
 
 
 void LCodeGen::DeoptimizeIfNegative(Register rt, LEnvironment* environment) {
-  Label dont_deopt;
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  __ Tbz(rt, rt.Is64Bits() ? kXSignBit : kWSignBit, &dont_deopt);
-  Deoptimize(environment, bailout_type);
-  __ Bind(&dont_deopt);
+  int sign_bit = rt.Is64Bits() ? kXSignBit : kWSignBit;
+  DeoptimizeBranch(environment, reg_bit_set, rt, sign_bit);
 }
 
 
 void LCodeGen::DeoptimizeIfSmi(Register rt,
                                LEnvironment* environment) {
-  Label dont_deopt;
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  __ JumpIfNotSmi(rt, &dont_deopt);
-  Deoptimize(environment, bailout_type);
-  __ Bind(&dont_deopt);
+  DeoptimizeBranch(environment, reg_bit_clear, rt, MaskToBit(kSmiTagMask));
 }
 
 
 void LCodeGen::DeoptimizeIfNotSmi(Register rt, LEnvironment* environment) {
-  Label dont_deopt;
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  __ JumpIfSmi(rt, &dont_deopt);
-  Deoptimize(environment, bailout_type);
-  __ Bind(&dont_deopt);
+  DeoptimizeBranch(environment, reg_bit_set, rt, MaskToBit(kSmiTagMask));
 }
 
 
 void LCodeGen::DeoptimizeIfRoot(Register rt,
                                 Heap::RootListIndex index,
                                 LEnvironment* environment) {
-  Label dont_deopt;
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  __ JumpIfNotRoot(rt, index, &dont_deopt);
-  Deoptimize(environment, bailout_type);
-  __ Bind(&dont_deopt);
+  __ CompareRoot(rt, index);
+  DeoptimizeIf(eq, environment);
 }
 
 
 void LCodeGen::DeoptimizeIfNotRoot(Register rt,
                                    Heap::RootListIndex index,
                                    LEnvironment* environment) {
-  Label dont_deopt;
-  Deoptimizer::BailoutType bailout_type = DeoptimizeHeader(environment, NULL);
-  __ JumpIfRoot(rt, index, &dont_deopt);
-  Deoptimize(environment, bailout_type);
-  __ Bind(&dont_deopt);
+  __ CompareRoot(rt, index);
+  DeoptimizeIf(ne, environment);
 }
 
 
@@ -2126,9 +2116,6 @@ void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
 
 void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
   if (!instr->hydrogen()->value()->IsHeapObject()) {
-    // TODO(all): Depending of how we chose to implement the deopt, if we could
-    // guarantee that we have a deopt handler reachable by a tbz instruction,
-    // we could use tbz here and produce less code to support this instruction.
     DeoptimizeIfSmi(ToRegister(instr->value()), instr->environment());
   }
 }
@@ -2137,7 +2124,6 @@ void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
 void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
   Register value = ToRegister(instr->value());
   ASSERT(!instr->result() || ToRegister(instr->result()).Is(value));
-  // TODO(all): See DoCheckNonSmi for comments on use of tbz.
   DeoptimizeIfNotSmi(value, instr->environment());
 }