Optimize isFinite and isNaN.

src/mips/code-stubs-mips.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 3520 matching lines @@
     masm->bal(&find_ra);  // bal exposes branch delay slot.
     masm->nop();  // Branch delay slot nop.
     masm->bind(&find_ra);
 
     // Adjust the value in ra to point to the correct return location, 2nd
     // instruction past the real call into C code (the jalr(t9)), and push it.
     // This is the return address of the exit frame.
     const int kNumInstructionsToJump = 6;
     masm->Addu(ra, ra, kNumInstructionsToJump * kPointerSize);
     masm->sw(ra, MemOperand(sp));  // This spot was reserved in EnterExitFrame.
-    masm->Subu(sp, sp, kCArgsSlotsSize);
+    masm->Subu(sp, sp, StandardFrameConstants::kCArgsSlotsSize);
     // Stack is still aligned.
 
     // Call the C routine.
     masm->mov(t9, s2);  // Function pointer to t9 to conform to ABI for PIC.
     masm->jalr(t9);
     masm->nop();    // Branch delay slot nop.
     // Make sure the stored 'ra' points to this position.
     ASSERT_EQ(kNumInstructionsToJump,
               masm->InstructionsGeneratedSince(&find_ra));
   }
 
   // Restore stack (remove arg slots).
-  __ Addu(sp, sp, kCArgsSlotsSize);
+  __ Addu(sp, sp, StandardFrameConstants::kCArgsSlotsSize);
 
   if (always_allocate) {
     // It's okay to clobber a2 and a3 here. v0 & v1 contain result.
     __ li(a2, Operand(scope_depth));
     __ lw(a3, MemOperand(a2));
     __ Subu(a3, a3, Operand(1));
     __ sw(a3, MemOperand(a2));
   }
 
   // Check for failure result.
@@ skipping 135 matching lines @@
     // Save callee-saved FPU registers.
     __ MultiPushFPU(kCalleeSavedFPU);
   }
 
   // Load argv in s0 register.
   int offset_to_argv = (kNumCalleeSaved + 1) * kPointerSize;
   if (CpuFeatures::IsSupported(FPU)) {
     offset_to_argv += kNumCalleeSavedFPU * kDoubleSize;
   }
 
-  __ lw(s0, MemOperand(sp, offset_to_argv + kCArgsSlotsSize));
+  __ lw(s0, MemOperand(sp, offset_to_argv +
+        StandardFrameConstants::kCArgsSlotsSize));
 
   // We build an EntryFrame.
   __ li(t3, Operand(-1));  // Push a bad frame pointer to fail if it is used.
   int marker = is_construct ? StackFrame::ENTRY_CONSTRUCT : StackFrame::ENTRY;
   __ li(t2, Operand(Smi::FromInt(marker)));
   __ li(t1, Operand(Smi::FromInt(marker)));
   __ li(t0, Operand(ExternalReference(Isolate::k_c_entry_fp_address,
                                       masm->isolate())));
   __ lw(t0, MemOperand(t0));
   __ Push(t3, t2, t1, t0);
@@ skipping 1914 matching lines @@
   //  0 <= from <= to <= string.length.
   // If any of these assumptions fail, we call the runtime system.
 
   static const int kToOffset = 0 * kPointerSize;
   static const int kFromOffset = 1 * kPointerSize;
   static const int kStringOffset = 2 * kPointerSize;
 
   Register to = t2;
   Register from = t3;
 
+  if (FLAG_string_slices) {
+    __ nop();  // Jumping as first instruction would crash the code generation.
+    __ jmp(&sub_string_runtime);
+  }
+
   // Check bounds and smi-ness.
   __ lw(to, MemOperand(sp, kToOffset));
   __ lw(from, MemOperand(sp, kFromOffset));
   STATIC_ASSERT(kFromOffset == kToOffset + 4);
   STATIC_ASSERT(kSmiTag == 0);
   STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
 
   __ JumpIfNotSmi(from, &sub_string_runtime);
   __ JumpIfNotSmi(to, &sub_string_runtime);
 
   __ sra(a3, from, kSmiTagSize);  // Remove smi tag.
   __ sra(t5, to, kSmiTagSize);  // Remove smi tag.
 
   // a3: from index (untagged smi)
   // t5: to index (untagged smi)
 
   __ Branch(&sub_string_runtime, lt, a3, Operand(zero_reg));  // From < 0.
 
   __ subu(a2, t5, a3);
   __ Branch(&sub_string_runtime, gt, a3, Operand(t5));  // Fail if from > to.
 
   // Special handling of sub-strings of length 1 and 2. One character strings
   // are handled in the runtime system (looked up in the single character
-  // cache). Two character strings are looked for in the symbol cache in
-  // generated code.
+  // cache). Two character strings are looked for in the symbol cache.
   __ Branch(&sub_string_runtime, lt, a2, Operand(2));
 
   // Both to and from are smis.
 
   // a2: result string length
   // a3: from index (untagged smi)
   // t2: (a.k.a. to): to (smi)
   // t3: (a.k.a. from): from offset (smi)
   // t5: to index (untagged smi)
 
   // Make sure first argument is a sequential (or flat) string.
-  __ lw(v0, MemOperand(sp, kStringOffset));
-  __ Branch(&sub_string_runtime, eq, v0, Operand(kSmiTagMask));
+  __ lw(t1, MemOperand(sp, kStringOffset));
+  __ Branch(&sub_string_runtime, eq, t1, Operand(kSmiTagMask));
 
-  __ lw(a1, FieldMemOperand(v0, HeapObject::kMapOffset));
+  __ lw(a1, FieldMemOperand(t1, HeapObject::kMapOffset));
   __ lbu(a1, FieldMemOperand(a1, Map::kInstanceTypeOffset));
-  __ And(t4, v0, Operand(kIsNotStringMask));
+  __ And(t4, a1, Operand(kIsNotStringMask));
 
   __ Branch(&sub_string_runtime, ne, t4, Operand(zero_reg));
 
-  // Short-cut for the case of trivial substring.
-  Label return_v0;
-  // v0: original string
-  // a2: result string length
-  __ lw(t0, FieldMemOperand(v0, String::kLengthOffset));
-  __ sra(t0, t0, 1);
-  __ Branch(&return_v0, eq, a2, Operand(t0));
-
-  Label create_slice;
-  if (FLAG_string_slices) {
-    __ Branch(&create_slice, ge, a2, Operand(SlicedString::kMinLength));
-  }
-
-  // v0: original string
   // a1: instance type
   // a2: result string length
   // a3: from index (untagged smi)
+  // t1: string
   // t2: (a.k.a. to): to (smi)
   // t3: (a.k.a. from): from offset (smi)
   // t5: to index (untagged smi)
 
   Label seq_string;
   __ And(t0, a1, Operand(kStringRepresentationMask));
   STATIC_ASSERT(kSeqStringTag < kConsStringTag);
   STATIC_ASSERT(kConsStringTag < kExternalStringTag);
-  STATIC_ASSERT(kConsStringTag < kSlicedStringTag);
 
-  // Slices and external strings go to runtime.
+  // External strings go to runtime.
   __ Branch(&sub_string_runtime, gt, t0, Operand(kConsStringTag));
 
   // Sequential strings are handled directly.
   __ Branch(&seq_string, lt, t0, Operand(kConsStringTag));
 
   // Cons string. Try to recurse (once) on the first substring.
   // (This adds a little more generality than necessary to handle flattened
   // cons strings, but not much).
-  __ lw(v0, FieldMemOperand(v0, ConsString::kFirstOffset));
-  __ lw(t0, FieldMemOperand(v0, HeapObject::kMapOffset));
+  __ lw(t1, FieldMemOperand(t1, ConsString::kFirstOffset));
+  __ lw(t0, FieldMemOperand(t1, HeapObject::kMapOffset));
   __ lbu(a1, FieldMemOperand(t0, Map::kInstanceTypeOffset));
   STATIC_ASSERT(kSeqStringTag == 0);
-  // Cons, slices and external strings go to runtime.
+  // Cons and External strings go to runtime.
   __ Branch(&sub_string_runtime, ne, a1, Operand(kStringRepresentationMask));
 
   // Definitly a sequential string.
   __ bind(&seq_string);
 
-  // v0: original string
   // a1: instance type
   // a2: result string length
   // a3: from index (untagged smi)
+  // t1: string
   // t2: (a.k.a. to): to (smi)
   // t3: (a.k.a. from): from offset (smi)
   // t5: to index (untagged smi)
 
-  __ lw(t0, FieldMemOperand(v0, String::kLengthOffset));
+  __ lw(t0, FieldMemOperand(t1, String::kLengthOffset));
   __ Branch(&sub_string_runtime, lt, t0, Operand(to));  // Fail if to > length.
   to = no_reg;
 
-  // v0: original string or left hand side of the original cons string.
   // a1: instance type
   // a2: result string length
   // a3: from index (untagged smi)
+  // t1: string
   // t3: (a.k.a. from): from offset (smi)
   // t5: to index (untagged smi)
 
   // Check for flat ASCII string.
   Label non_ascii_flat;
   STATIC_ASSERT(kTwoByteStringTag == 0);
 
   __ And(t4, a1, Operand(kStringEncodingMask));
   __ Branch(&non_ascii_flat, eq, t4, Operand(zero_reg));
 
   Label result_longer_than_two;
   __ Branch(&result_longer_than_two, gt, a2, Operand(2));
 
   // Sub string of length 2 requested.
   // Get the two characters forming the sub string.
-  __ Addu(v0, v0, Operand(a3));
-  __ lbu(a3, FieldMemOperand(v0, SeqAsciiString::kHeaderSize));
-  __ lbu(t0, FieldMemOperand(v0, SeqAsciiString::kHeaderSize + 1));
+  __ Addu(t1, t1, Operand(a3));
+  __ lbu(a3, FieldMemOperand(t1, SeqAsciiString::kHeaderSize));
+  __ lbu(t0, FieldMemOperand(t1, SeqAsciiString::kHeaderSize + 1));
 
   // Try to lookup two character string in symbol table.
   Label make_two_character_string;
   StringHelper::GenerateTwoCharacterSymbolTableProbe(
       masm, a3, t0, a1, t1, t2, t3, t4, &make_two_character_string);
   Counters* counters = masm->isolate()->counters();
-  __ jmp(&return_v0);
+  __ IncrementCounter(counters->sub_string_native(), 1, a3, t0);
+  __ Addu(sp, sp, Operand(3 * kPointerSize));
+  __ Ret();
+
 
   // a2: result string length.
   // a3: two characters combined into halfword in little endian byte order.
   __ bind(&make_two_character_string);
   __ AllocateAsciiString(v0, a2, t0, t1, t4, &sub_string_runtime);
   __ sh(a3, FieldMemOperand(v0, SeqAsciiString::kHeaderSize));
-  __ jmp(&return_v0);
+  __ IncrementCounter(counters->sub_string_native(), 1, a3, t0);
+  __ Addu(sp, sp, Operand(3 * kPointerSize));
+  __ Ret();
 
   __ bind(&result_longer_than_two);
 
-  // Locate 'from' character of string.
-  __ Addu(t1, v0, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
-  __ sra(t4, from, 1);
-  __ Addu(t1, t1, t4);
-
   // Allocate the result.
   __ AllocateAsciiString(v0, a2, t4, t0, a1, &sub_string_runtime);
 
-  // v0: result string
-  // a2: result string length
+  // v0: result string.
+  // a2: result string length.
   // a3: from index (untagged smi)
-  // t1: first character of substring to copy
+  // t1: string.
   // t3: (a.k.a. from): from offset (smi)
   // Locate first character of result.
   __ Addu(a1, v0, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  // Locate 'from' character of string.
+  __ Addu(t1, t1, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+  __ Addu(t1, t1, Operand(a3));
 
-  // v0: result string
-  // a1: first character of result string
-  // a2: result string length
-  // t1: first character of substring to copy
+  // v0: result string.
+  // a1: first character of result string.
+  // a2: result string length.
+  // t1: first character of sub string to copy.
   STATIC_ASSERT((SeqAsciiString::kHeaderSize & kObjectAlignmentMask) == 0);
   StringHelper::GenerateCopyCharactersLong(
       masm, a1, t1, a2, a3, t0, t2, t3, t4, COPY_ASCII | DEST_ALWAYS_ALIGNED);
-  __ jmp(&return_v0);
+  __ IncrementCounter(counters->sub_string_native(), 1, a3, t0);
+  __ Addu(sp, sp, Operand(3 * kPointerSize));
+  __ Ret();
 
   __ bind(&non_ascii_flat);
-  // a2: result string length
-  // t1: string
+  // a2: result string length.
+  // t1: string.
   // t3: (a.k.a. from): from offset (smi)
   // Check for flat two byte string.
 
-  // Locate 'from' character of string.
-  __ Addu(t1, v0, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-  // As "from" is a smi it is 2 times the value which matches the size of a two
-  // byte character.
-  STATIC_ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
-  __ Addu(t1, t1, Operand(from));
-
   // Allocate the result.
   __ AllocateTwoByteString(v0, a2, a1, a3, t0, &sub_string_runtime);
 
-  // v0: result string
-  // a2: result string length
-  // t1: first character of substring to copy
+  // v0: result string.
+  // a2: result string length.
+  // t1: string.
   // Locate first character of result.
   __ Addu(a1, v0, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
-
+  // Locate 'from' character of string.
+  __ Addu(t1, t1, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+  // As "from" is a smi it is 2 times the value which matches the size of a two
+  // byte character.
+  __ Addu(t1, t1, Operand(from));
   from = no_reg;
 
   // v0: result string.
   // a1: first character of result.
   // a2: result length.
-  // t1: first character of substring to copy.
+  // t1: first character of string to copy.
   STATIC_ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
   StringHelper::GenerateCopyCharactersLong(
       masm, a1, t1, a2, a3, t0, t2, t3, t4, DEST_ALWAYS_ALIGNED);
-  __ jmp(&return_v0);
-
-  if (FLAG_string_slices) {
-    __ bind(&create_slice);
-    // v0: original string
-    // a1: instance type
-    // a2: length
-    // a3: from index (untagged smi)
-    // t2 (a.k.a. to): to (smi)
-    // t3 (a.k.a. from): from offset (smi)
-    Label allocate_slice, sliced_string, seq_string;
-    STATIC_ASSERT(kSeqStringTag == 0);
-    __ And(t4, a1, Operand(kStringRepresentationMask));
-    __ Branch(&seq_string, eq, t4, Operand(zero_reg));
-    STATIC_ASSERT(kIsIndirectStringMask == (kSlicedStringTag & kConsStringTag));
-    STATIC_ASSERT(kIsIndirectStringMask != 0);
-    __ And(t4, a1, Operand(kIsIndirectStringMask));
-    // External string.  Jump to runtime.
-    __ Branch(&sub_string_runtime, eq, t4, Operand(zero_reg));
-
-    __ And(t4, a1, Operand(kSlicedNotConsMask));
-    __ Branch(&sliced_string, ne, t4, Operand(zero_reg));
-    // Cons string.  Check whether it is flat, then fetch first part.
-    __ lw(t1, FieldMemOperand(v0, ConsString::kSecondOffset));
-    __ LoadRoot(t5, Heap::kEmptyStringRootIndex);
-    __ Branch(&sub_string_runtime, ne, t1, Operand(t5));
-    __ lw(t1, FieldMemOperand(v0, ConsString::kFirstOffset));
-    __ jmp(&allocate_slice);
-
-    __ bind(&sliced_string);
-    // Sliced string.  Fetch parent and correct start index by offset.
-    __ lw(t1, FieldMemOperand(v0, SlicedString::kOffsetOffset));
-    __ addu(t3, t3, t1);
-    __ lw(t1, FieldMemOperand(v0, SlicedString::kParentOffset));
-    __ jmp(&allocate_slice);
-
-    __ bind(&seq_string);
-    // Sequential string.  Just move string to the right register.
-    __ mov(t1, v0);
-
-    __ bind(&allocate_slice);
-    // a1: instance type of original string
-    // a2: length
-    // t1: underlying subject string
-    // t3 (a.k.a. from): from offset (smi)
-    // Allocate new sliced string.  At this point we do not reload the instance
-    // type including the string encoding because we simply rely on the info
-    // provided by the original string.  It does not matter if the original
-    // string's encoding is wrong because we always have to recheck encoding of
-    // the newly created string's parent anyways due to externalized strings.
-    Label two_byte_slice, set_slice_header;
-    STATIC_ASSERT((kStringEncodingMask & kAsciiStringTag) != 0);
-    STATIC_ASSERT((kStringEncodingMask & kTwoByteStringTag) == 0);
-    __ And(t4, a1, Operand(kStringEncodingMask));
-    __ Branch(&two_byte_slice, eq, t4, Operand(zero_reg));
-    __ AllocateAsciiSlicedString(v0, a2, a3, t0, &sub_string_runtime);
-    __ jmp(&set_slice_header);
-    __ bind(&two_byte_slice);
-    __ AllocateTwoByteSlicedString(v0, a2, a3, t0, &sub_string_runtime);
-    __ bind(&set_slice_header);
-    __ sw(t3, FieldMemOperand(v0, SlicedString::kOffsetOffset));
-    __ sw(t1, FieldMemOperand(v0, SlicedString::kParentOffset));
-  }
-
-  __ bind(&return_v0);
   __ IncrementCounter(counters->sub_string_native(), 1, a3, t0);
   __ Addu(sp, sp, Operand(3 * kPointerSize));
   __ Ret();
 
   // Just jump to runtime to create the sub string.
   __ bind(&sub_string_runtime);
   __ TailCallRuntime(Runtime::kSubString, 3, 1);
 }
 
 
@@ skipping 1040 matching lines @@
   __ mov(result, zero_reg);
   __ Ret();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS