Fixing generated hash function on all platforms.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index cd269cb6f3e0395c04832e73fe93c837d4707e82..2001b80d82e47397f98744675ea0b86ad53bffbf 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -4705,6 +4705,7 @@ void StringHelper::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
   static const int kProbes = 4;
   Label found_in_symbol_table;
   Label next_probe[kProbes];
+  Register candidate = scratch;  // Scratch register contains candidate.
   for (int i = 0; i < kProbes; i++) {
     // Calculate entry in symbol table.
     __ movl(scratch, hash);
@@ -4714,7 +4715,6 @@ void StringHelper::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
     __ andl(scratch, mask);
 
     // Load the entry from the symbol table.
-    Register candidate = scratch;  // Scratch register contains candidate.
     STATIC_ASSERT(SymbolTable::kEntrySize == 1);
     __ movq(candidate,
             FieldOperand(symbol_table,
@@ -4729,7 +4729,12 @@ void StringHelper::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
 
     __ CompareRoot(candidate, Heap::kUndefinedValueRootIndex);
     __ j(equal, not_found);
-    // Must be null (deleted entry).
+    // Must be the hole (deleted entry).
+    if (FLAG_debug_code) {
+      __ LoadRoot(kScratchRegister, Heap::kTheHoleValueRootIndex);
+      __ cmpq(kScratchRegister, candidate);
+      __ Assert(equal, "oddball in symbol table is not undefined or the hole");
+    }
     __ jmp(&next_probe[i]);
 
     __ bind(&is_string);
@@ -4760,7 +4765,7 @@ void StringHelper::GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
   __ jmp(not_found);
 
   // Scratch register contains result when we fall through to here.
-  Register result = scratch;
+  Register result = candidate;
   __ bind(&found_in_symbol_table);
   if (!result.is(rax)) {
     __ movq(rax, result);
@@ -4778,7 +4783,7 @@ void StringHelper::GenerateHashInit(MacroAssembler* masm,
   __ addl(hash, character);
   // hash ^= hash >> 6;
   __ movl(scratch, hash);
-  __ sarl(scratch, Immediate(6));
+  __ shrl(scratch, Immediate(6));
   __ xorl(hash, scratch);
 }
 
@@ -4795,7 +4800,7 @@ void StringHelper::GenerateHashAddCharacter(MacroAssembler* masm,
   __ addl(hash, scratch);
   // hash ^= hash >> 6;
   __ movl(scratch, hash);
-  __ sarl(scratch, Immediate(6));
+  __ shrl(scratch, Immediate(6));
   __ xorl(hash, scratch);
 }
 
@@ -4807,13 +4812,16 @@ void StringHelper::GenerateHashGetHash(MacroAssembler* masm,
   __ leal(hash, Operand(hash, hash, times_8, 0));
   // hash ^= hash >> 11;
   __ movl(scratch, hash);
-  __ sarl(scratch, Immediate(11));
+  __ shrl(scratch, Immediate(11));
   __ xorl(hash, scratch);
   // hash += hash << 15;
   __ movl(scratch, hash);
   __ shll(scratch, Immediate(15));
   __ addl(hash, scratch);
 
+  uint32_t kHashShiftCutOffMask = (1 << (32 - String::kHashShift)) - 1;
+  __ andl(hash, Immediate(kHashShiftCutOffMask));
+
   // if (hash == 0) hash = 27;
   Label hash_not_zero;
   __ j(not_zero, &hash_not_zero);