Code cleanup in GenerateRecordCallTarget.

BUG=

Review URL: https://codereview.chromium.org/1057613003

Cr-Commit-Position: refs/heads/master@{#27630}

src/arm/code-stubs-arm.cc

@@ -2364,7 +2364,7 @@ static void CallStubInRecordCallTarget(MacroAssembler* masm, CodeStub* stub) {
   // r1 : the function to call
   FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
 
-  // Arguments register must be smi-tagged to call out.
+  // Number-of-arguments register must be smi-tagged to call out.
   __ SmiTag(r0);
   __ Push(r3, r2, r1, r0);
 
@@ -2396,6 +2396,8 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
 
   // A monomorphic cache hit or an already megamorphic state: invoke the
   // function without changing the state.
+  // We don't know if r4 is a WeakCell or a Symbol, but it's harmless to read at
+  // this position in a symbol (see static asserts in type-feedback-vector.h).
   Label check_allocation_site;
   Register feedback_map = r5;
   Register weak_value = r8;
@@ -2404,12 +2406,11 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   __ b(eq, &done);
   __ CompareRoot(r4, Heap::kmegamorphic_symbolRootIndex);
   __ b(eq, &done);
-  __ ldr(feedback_map, FieldMemOperand(r4, 0));
+  __ ldr(feedback_map, FieldMemOperand(r4, HeapObject::kMapOffset));
   __ CompareRoot(feedback_map, Heap::kWeakCellMapRootIndex);
   __ b(ne, FLAG_pretenuring_call_new ? &miss : &check_allocation_site);
 
-  // If r1 is not equal to the weak cell value, and the weak cell value is
-  // cleared, we have a new chance to become monomorphic.
+  // If the weak cell is cleared, we have a new chance to become monomorphic.
   __ JumpIfSmi(weak_value, &initialize);
   __ jmp(&megamorphic);
 
@@ -2418,7 +2419,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
     // If we came here, we need to see if we are the array function.
     // If we didn't have a matching function, and we didn't find the megamorph
     // sentinel, then we have in the slot either some other function or an
-    // AllocationSite. Do a map check on the object in ecx.
+    // AllocationSite.
     __ CompareRoot(feedback_map, Heap::kAllocationSiteMapRootIndex);
     __ b(ne, &miss);
 

src/arm64/code-stubs-arm64.cc

@@ -2736,7 +2736,7 @@ static void CallStubInRecordCallTarget(MacroAssembler* masm, CodeStub* stub,
                                        Register index) {
   FrameScope scope(masm, StackFrame::INTERNAL);
 
-  // Arguments register must be smi-tagged to call out.
+  // Number-of-arguments register must be smi-tagged to call out.
   __ SmiTag(argc);
   __ Push(argc, function, feedback_vector, index);
 
@@ -2779,18 +2779,20 @@ static void GenerateRecordCallTarget(MacroAssembler* masm, Register argc,
 
   // A monomorphic cache hit or an already megamorphic state: invoke the
   // function without changing the state.
+  // We don't know if feedback value is a WeakCell or a Symbol, but it's
+  // harmless to read at this position in a symbol (see static asserts in
+  // type-feedback-vector.h).
   Label check_allocation_site;
   __ Ldr(feedback_value, FieldMemOperand(feedback, WeakCell::kValueOffset));
   __ Cmp(function, feedback_value);
   __ B(eq, &done);
   __ CompareRoot(feedback, Heap::kmegamorphic_symbolRootIndex);
   __ B(eq, &done);
-  __ Ldr(feedback_map, FieldMemOperand(feedback, 0));
+  __ Ldr(feedback_map, FieldMemOperand(feedback, HeapObject::kMapOffset));
   __ CompareRoot(feedback_map, Heap::kWeakCellMapRootIndex);
   __ B(ne, FLAG_pretenuring_call_new ? &miss : &check_allocation_site);
 
-  // If function is not equal to the weak cell value, and the weak cell value is
-  // cleared, we have a new chance to become monomorphic.
+  // If the weak cell is cleared, we have a new chance to become monomorphic.
   __ JumpIfSmi(feedback_value, &initialize);
   __ B(&megamorphic);
 
@@ -2799,7 +2801,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm, Register argc,
     // If we came here, we need to see if we are the array function.
     // If we didn't have a matching function, and we didn't find the megamorph
     // sentinel, then we have in the slot either some other function or an
-    // AllocationSite. Do a map check on the object in scratch1 register.
+    // AllocationSite.
     __ JumpIfNotRoot(feedback_map, Heap::kAllocationSiteMapRootIndex, &miss);
 
     // Make sure the function is the Array() function

src/ia32/code-stubs-ia32.cc

@@ -1920,7 +1920,7 @@ static void CallStubInRecordCallTarget(MacroAssembler* masm, CodeStub* stub) {
   // edi : the function to call
   FrameScope scope(masm, StackFrame::INTERNAL);
 
-  // Arguments register must be smi-tagged to call out.
+  // Number-of-arguments register must be smi-tagged to call out.
   __ SmiTag(eax);
   __ push(eax);
   __ push(edi);
@@ -1954,16 +1954,19 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
 
   // A monomorphic cache hit or an already megamorphic state: invoke the
   // function without changing the state.
+  // We don't know if ecx is a WeakCell or a Symbol, but it's harmless to read
+  // at this position in a symbol (see static asserts in
+  // type-feedback-vector.h).
   Label check_allocation_site;
   __ cmp(edi, FieldOperand(ecx, WeakCell::kValueOffset));
   __ j(equal, &done, Label::kFar);
   __ CompareRoot(ecx, Heap::kmegamorphic_symbolRootIndex);
   __ j(equal, &done, Label::kFar);
-  __ CompareRoot(FieldOperand(ecx, 0), Heap::kWeakCellMapRootIndex);
+  __ CompareRoot(FieldOperand(ecx, HeapObject::kMapOffset),
+                 Heap::kWeakCellMapRootIndex);
   __ j(not_equal, FLAG_pretenuring_call_new ? &miss : &check_allocation_site);
 
-  // If edi is not equal to the weak cell value, and the weak cell value is
-  // cleared, we have a new chance to become monomorphic.
+  // If the weak cell is cleared, we have a new chance to become monomorphic.
   __ JumpIfSmi(FieldOperand(ecx, WeakCell::kValueOffset), &initialize);
   __ jmp(&megamorphic);
 
@@ -1972,7 +1975,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
     // If we came here, we need to see if we are the array function.
     // If we didn't have a matching function, and we didn't find the megamorph
     // sentinel, then we have in the slot either some other function or an
-    // AllocationSite. Do a map check on the object in ecx.
+    // AllocationSite.
     __ CompareRoot(FieldOperand(ecx, 0), Heap::kAllocationSiteMapRootIndex);
     __ j(not_equal, &miss);
 

src/mips/code-stubs-mips.cc

@@ -2505,7 +2505,7 @@ static void CallStubInRecordCallTarget(MacroAssembler* masm, CodeStub* stub) {
                              1 << 6 |  // a2
                              1 << 7;   // a3
 
-  // Arguments register must be smi-tagged to call out.
+  // Number-of-arguments register must be smi-tagged to call out.
   __ SmiTag(a0);
   __ MultiPush(kSavedRegs);
 
@@ -2538,6 +2538,8 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
 
   // A monomorphic cache hit or an already megamorphic state: invoke the
   // function without changing the state.
+  // We don't know if t0 is a WeakCell or a Symbol, but it's harmless to read at
+  // this position in a symbol (see static asserts in type-feedback-vector.h).
   Label check_allocation_site;
   Register feedback_map = t1;
   Register weak_value = t4;
@@ -2545,13 +2547,12 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   __ Branch(&done, eq, a1, Operand(weak_value));
   __ LoadRoot(at, Heap::kmegamorphic_symbolRootIndex);
   __ Branch(&done, eq, t0, Operand(at));
-  __ lw(feedback_map, FieldMemOperand(t0, 0));
+  __ lw(feedback_map, FieldMemOperand(t0, Heap::kMapOffset));
   __ LoadRoot(at, Heap::kWeakCellMapRootIndex);
   __ Branch(FLAG_pretenuring_call_new ? &miss : &check_allocation_site, ne,
             feedback_map, Operand(at));
 
-  // If a1 is not equal to the weak cell value, and the weak cell value is
-  // cleared, we have a new chance to become monomorphic.
+  // If the weak cell is cleared, we have a new chance to become monomorphic.
   __ JumpIfSmi(weak_value, &initialize);
   __ jmp(&megamorphic);
 
@@ -2560,7 +2561,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
     // If we came here, we need to see if we are the array function.
     // If we didn't have a matching function, and we didn't find the megamorph
     // sentinel, then we have in the slot either some other function or an
-    // AllocationSite. Do a map check on the object in a3.
+    // AllocationSite.
     __ LoadRoot(at, Heap::kAllocationSiteMapRootIndex);
     __ Branch(&miss, ne, feedback_map, Operand(at));
 

src/mips64/code-stubs-mips64.cc

@@ -2541,7 +2541,7 @@ static void CallStubInRecordCallTarget(MacroAssembler* masm, CodeStub* stub) {
                              1 << 6 |  // a2
                              1 << 7;   // a3
 
-  // Arguments register must be smi-tagged to call out.
+  // Number-of-arguments register must be smi-tagged to call out.
   __ SmiTag(a0);
   __ MultiPush(kSavedRegs);
 
@@ -2574,6 +2574,8 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
 
   // A monomorphic cache hit or an already megamorphic state: invoke the
   // function without changing the state.
+  // We don't know if a4 is a WeakCell or a Symbol, but it's harmless to read at
+  // this position in a symbol (see static asserts in type-feedback-vector.h).
   Label check_allocation_site;
   Register feedback_map = a5;
   Register weak_value = t0;
@@ -2581,13 +2583,12 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   __ Branch(&done, eq, a1, Operand(weak_value));
   __ LoadRoot(at, Heap::kmegamorphic_symbolRootIndex);
   __ Branch(&done, eq, a4, Operand(at));
-  __ ld(feedback_map, FieldMemOperand(a4, 0));
+  __ ld(feedback_map, FieldMemOperand(a4, HeapObject::kMapOffset));
   __ LoadRoot(at, Heap::kWeakCellMapRootIndex);
   __ Branch(FLAG_pretenuring_call_new ? &miss : &check_allocation_site, ne,
             feedback_map, Operand(at));
 
-  // If a1 is not equal to the weak cell value, and the weak cell value is
-  // cleared, we have a new chance to become monomorphic.
+  // If the weak cell is cleared, we have a new chance to become monomorphic.
   __ JumpIfSmi(weak_value, &initialize);
   __ jmp(&megamorphic);
 
@@ -2596,7 +2597,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
     // If we came here, we need to see if we are the array function.
     // If we didn't have a matching function, and we didn't find the megamorph
     // sentinel, then we have in the slot either some other function or an
-    // AllocationSite. Do a map check on the object in a3.
+    // AllocationSite.
     __ LoadRoot(at, Heap::kAllocationSiteMapRootIndex);
     __ Branch(&miss, ne, feedback_map, Operand(at));
 

src/x64/code-stubs-x64.cc

@@ -1785,7 +1785,7 @@ static void CallStubInRecordCallTarget(MacroAssembler* masm, CodeStub* stub) {
   // edi : the function to call
   FrameScope scope(masm, StackFrame::INTERNAL);
 
-  // Arguments register must be smi-tagged to call out.
+  // Number-of-arguments register must be smi-tagged to call out.
   __ Integer32ToSmi(rax, rax);
   __ Push(rax);
   __ Push(rdi);
@@ -1822,17 +1822,19 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
 
   // A monomorphic cache hit or an already megamorphic state: invoke the
   // function without changing the state.
+  // We don't know if rcx is a WeakCell or a Symbol, but it's harmless to read
+  // at this position in a symbol (see static asserts in
+  // type-feedback-vector.h).
   Label check_allocation_site;
   __ cmpp(rdi, FieldOperand(rcx, WeakCell::kValueOffset));
   __ j(equal, &done, Label::kFar);
   __ CompareRoot(rcx, Heap::kmegamorphic_symbolRootIndex);
   __ j(equal, &done, Label::kFar);
-  __ CompareRoot(FieldOperand(rcx, 0), Heap::kWeakCellMapRootIndex);
+  __ CompareRoot(FieldOperand(rcx, HeapObject::kMapOffset),
+                 Heap::kWeakCellMapRootIndex);
   __ j(not_equal, FLAG_pretenuring_call_new ? &miss : &check_allocation_site);
 
-  // If edi is not equal to the weak cell value, and the weak cell value is
-  // cleared, we have a new chance to become monomorphic. Otherwise, we
-  // need to go megamorphic.
+  // If the weak cell is cleared, we have a new chance to become monomorphic.
   __ CheckSmi(FieldOperand(rcx, WeakCell::kValueOffset));
   __ j(equal, &initialize);
   __ jmp(&megamorphic);
@@ -1842,7 +1844,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
     // If we came here, we need to see if we are the array function.
     // If we didn't have a matching function, and we didn't find the megamorph
     // sentinel, then we have in the slot either some other function or an
-    // AllocationSite. Do a map check on the object in rcx.
+    // AllocationSite.
     __ CompareRoot(FieldOperand(rcx, 0), Heap::kAllocationSiteMapRootIndex);
     __ j(not_equal, &miss);