Fix SmiCompare on 64 bit to distinguish between comparisons where...

src/x64/code-stubs-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2226 matching lines @@
 
   // The displacement is used for skipping the frame pointer on the
   // stack. It is the offset of the last parameter (if any) relative
   // to the frame pointer.
   static const int kDisplacement = 1 * kPointerSize;
 
   // Check that the key is a smi.
   Label slow;
   __ JumpIfNotSmi(rdx, &slow);
 
-  // Check if the calling frame is an arguments adaptor frame.
+  // Check if the calling frame is an arguments adaptor frame.  We look at the
+  // context offset, and if the frame is not a regular one, then we find a
+  // Smi instead of the context.  We can't use SmiCompare here, because that
+  // only works for comparing two smis.
   Label adaptor;
   __ movq(rbx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
-  __ SmiCompare(Operand(rbx, StandardFrameConstants::kContextOffset),
-                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
+  __ Cmp(Operand(rbx, StandardFrameConstants::kContextOffset),
+         Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
   __ j(equal, &adaptor);
 
   // Check index against formal parameters count limit passed in
   // through register rax. Use unsigned comparison to get negative
   // check for free.
   __ cmpq(rdx, rax);
   __ j(above_equal, &slow);
 
   // Read the argument from the stack and return it.
   SmiIndex index = masm->SmiToIndex(rax, rax, kPointerSizeLog2);
@@ skipping 34 matching lines @@
   // rsp[24] : function
 
   // The displacement is used for skipping the return address and the
   // frame pointer on the stack. It is the offset of the last
   // parameter (if any) relative to the frame pointer.
   static const int kDisplacement = 2 * kPointerSize;
 
   // Check if the calling frame is an arguments adaptor frame.
   Label adaptor_frame, try_allocate, runtime;
   __ movq(rdx, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
-  __ SmiCompare(Operand(rdx, StandardFrameConstants::kContextOffset),
-                Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
+  __ Cmp(Operand(rdx, StandardFrameConstants::kContextOffset),
+         Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
   __ j(equal, &adaptor_frame);
 
   // Get the length from the frame.
   __ SmiToInteger32(rcx, Operand(rsp, 1 * kPointerSize));
   __ jmp(&try_allocate);
 
   // Patch the arguments.length and the parameters pointer.
   __ bind(&adaptor_frame);
   __ SmiToInteger32(rcx,
                     Operand(rdx,
@@ skipping 1832 matching lines @@
     __ movq(r8, FieldOperand(rax, HeapObject::kMapOffset));
     __ movq(r9, FieldOperand(rdx, HeapObject::kMapOffset));
   }
   // Get the instance types of the two strings as they will be needed soon.
   __ movzxbl(r8, FieldOperand(r8, Map::kInstanceTypeOffset));
   __ movzxbl(r9, FieldOperand(r9, Map::kInstanceTypeOffset));
 
   // Look at the length of the result of adding the two strings.
   STATIC_ASSERT(String::kMaxLength <= Smi::kMaxValue / 2);
   __ SmiAdd(rbx, rbx, rcx);
-  // Use the runtime system when adding two one character strings, as it
-  // contains optimizations for this specific case using the symbol table.
+  // Use the symbol table when adding two one character strings, as it
+  // helps later optimizations to return a symbol here.
   __ SmiCompare(rbx, Smi::FromInt(2));
   __ j(not_equal, &longer_than_two);
 
   // Check that both strings are non-external ascii strings.
   __ JumpIfBothInstanceTypesAreNotSequentialAscii(r8, r9, rbx, rcx,
                                                   &string_add_runtime);
 
   // Get the two characters forming the sub string.
   __ movzxbq(rbx, FieldOperand(rax, SeqAsciiString::kHeaderSize));
   __ movzxbq(rcx, FieldOperand(rdx, SeqAsciiString::kHeaderSize));
@@ skipping 331 matching lines @@
   // Load the symbol table.
   Register symbol_table = c2;
   __ LoadRoot(symbol_table, Heap::kSymbolTableRootIndex);
 
   // Calculate capacity mask from the symbol table capacity.
   Register mask = scratch2;
   __ SmiToInteger32(mask,
                     FieldOperand(symbol_table, SymbolTable::kCapacityOffset));
   __ decl(mask);
 
-  Register undefined = scratch4;
-  __ LoadRoot(undefined, Heap::kUndefinedValueRootIndex);
+  Register map = scratch4;
 
   // Registers
   // chars:        two character string, char 1 in byte 0 and char 2 in byte 1.
   // hash:         hash of two character string (32-bit int)
   // symbol_table: symbol table
   // mask:         capacity mask (32-bit int)
-  // undefined:    undefined value
+  // map:          -
   // scratch:      -
 
   // Perform a number of probes in the symbol table.
   static const int kProbes = 4;
   Label found_in_symbol_table;
   Label next_probe[kProbes];
   for (int i = 0; i < kProbes; i++) {
     // Calculate entry in symbol table.
     __ movl(scratch, hash);
     if (i > 0) {
       __ addl(scratch, Immediate(SymbolTable::GetProbeOffset(i)));
     }
     __ andl(scratch, mask);
 
-    // Load the entry from the symble table.
+    // Load the entry from the symbol table.
     Register candidate = scratch;  // Scratch register contains candidate.
     STATIC_ASSERT(SymbolTable::kEntrySize == 1);
     __ movq(candidate,
             FieldOperand(symbol_table,
                          scratch,
                          times_pointer_size,
                          SymbolTable::kElementsStartOffset));
 
     // If entry is undefined no string with this hash can be found.
-    __ cmpq(candidate, undefined);
+    NearLabel is_string;
+    __ CmpObjectType(candidate, ODDBALL_TYPE, map);
+    __ j(not_equal, &is_string);
+
+    __ CompareRoot(candidate, Heap::kUndefinedValueRootIndex);
     __ j(equal, not_found);
+    // Must be null (deleted entry).
+    __ jmp(&next_probe[i]);
+
+    __ bind(&is_string);
 
     // If length is not 2 the string is not a candidate.
     __ SmiCompare(FieldOperand(candidate, String::kLengthOffset),
                   Smi::FromInt(2));
     __ j(not_equal, &next_probe[i]);
 
     // We use kScratchRegister as a temporary register in assumption that
     // JumpIfInstanceTypeIsNotSequentialAscii does not use it implicitly
     Register temp = kScratchRegister;
 
     // Check that the candidate is a non-external ascii string.
-    __ movq(temp, FieldOperand(candidate, HeapObject::kMapOffset));
-    __ movzxbl(temp, FieldOperand(temp, Map::kInstanceTypeOffset));
+    __ movzxbl(temp, FieldOperand(map, Map::kInstanceTypeOffset));
     __ JumpIfInstanceTypeIsNotSequentialAscii(
         temp, temp, &next_probe[i]);
 
     // Check if the two characters match.
     __ movl(temp, FieldOperand(candidate, SeqAsciiString::kHeaderSize));
     __ andl(temp, Immediate(0x0000ffff));
     __ cmpl(chars, temp);
     __ j(equal, &found_in_symbol_table);
     __ bind(&next_probe[i]);
   }
@@ skipping 507 matching lines @@
   // Do a tail call to the rewritten stub.
   __ jmp(rdi);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64