Load(args->at(1));
Load(args->at(2));
- frame_->CallRuntime(Runtime::kSubString, 3);
+ SubStringStub stub;
+ frame_->CallStub(&stub, 3);
frame_->EmitPush(r0);
}
}
+void StringStubBase::GenerateCopyCharacters(MacroAssembler* masm,
+ Register dest,
+ Register src,
+ Register count,
+ Register scratch,
+ bool ascii) {
+ Label loop;
+ Label done;
+ // This loop just copies one character at a time, as it is only used for very
+ // short strings.
+ if (!ascii) {
+ __ add(count, count, Operand(count), SetCC);
+ } else {
+ __ cmp(count, Operand(0));
+ }
+ __ b(eq, &done);
+
+ __ bind(&loop);
+ __ sub(count, count, Operand(1), SetCC);
+ __ ldrb(scratch, MemOperand(src, count), pl);
+ // Move branch between load and dependent store to not waste the cycle for
+ // each iteration of the loop. It does cost an extra instruction on the
+ // last iteration.
+ __ b(mi, &done);
+ __ strb(scratch, MemOperand(dest, count));
+ __ b(&loop);
+ __ bind(&done);
+}
+
+
+enum CopyCharactersFlags {
+ COPY_ASCII = 1,
+ DEST_ALWAYS_ALIGNED = 2
+};
+
+
+void StringStubBase::GenerateCopyCharactersLong(MacroAssembler* masm,
+ Register dest,
+ Register src,
+ Register count,
+ Register scratch1,
+ Register scratch2,
+ Register scratch3,
+ Register scratch4,
+ Register scratch5,
+ int flags) {
+ bool ascii = (flags & COPY_ASCII) != 0;
+ bool dest_always_aligned = (flags & DEST_ALWAYS_ALIGNED) != 0;
+
+ if (dest_always_aligned && FLAG_debug_code) {
+ // Check that destination is actually word aligned if the flag says
+ // that it is.
+ __ tst(dest, Operand(kPointerAlignmentMask));
+ __ Check(eq, "Destination of copy not aligned.");
+ }
+
+ const int kReadAlignment = 4;
+ const int kReadAlignmentMask = kReadAlignment - 1;
+ // Ensure that reading an entire aligned word containing the last character
+ // of a string will not read outside the allocated area (because we pad up
+ // to kObjectAlignment).
+ ASSERT(kObjectAlignment >= kReadAlignment);
+ // Assumes word reads and writes are little endian.
+ // Nothing to do for zero characters.
+ Label done;
+ if (!ascii) {
+ __ add(count, count, Operand(count), SetCC);
+ } else {
+ __ cmp(count, Operand(0));
+ }
+ __ b(eq, &done);
+
+ // Assume that you cannot read (or write) unaligned.
+ Label byte_loop;
+ // Must copy at least eight bytes, otherwise just do it one byte at a time.
+ __ cmp(count, Operand(8));
+ __ add(count, dest, Operand(count));
+ Register limit = count; // Read until src equals this.
+ __ b(lt, &byte_loop);
+
+ if (!dest_always_aligned) {
+ // Align dest by byte copying. Copies between zero and three bytes.
+ __ and_(scratch4, dest, Operand(kReadAlignmentMask), SetCC);
+ Label dest_aligned;
+ __ b(eq, &dest_aligned);
+ __ cmp(scratch4, Operand(2));
+ __ ldrb(scratch1, MemOperand(src, 1, PostIndex));
+ __ ldrb(scratch2, MemOperand(src, 1, PostIndex), le);
+ __ ldrb(scratch3, MemOperand(src, 1, PostIndex), lt);
+ __ strb(scratch1, MemOperand(dest, 1, PostIndex));
+ __ strb(scratch2, MemOperand(dest, 1, PostIndex), le);
+ __ strb(scratch3, MemOperand(dest, 1, PostIndex), lt);
+ __ bind(&dest_aligned);
+ }
+
+ Label simple_loop;
+
+ __ sub(scratch4, dest, Operand(src));
+ __ and_(scratch4, scratch4, Operand(0x03), SetCC);
+ __ b(eq, &simple_loop);
+ // Shift register is number of bits in a source word that
+ // must be combined with bits in the next source word in order
+ // to create a destination word.
+
+ // Complex loop for src/dst that are not aligned the same way.
+ {
+ Label loop;
+ __ mov(scratch4, Operand(scratch4, LSL, 3));
+ Register left_shift = scratch4;
+ __ and_(src, src, Operand(~3)); // Round down to load previous word.
+ __ ldr(scratch1, MemOperand(src, 4, PostIndex));
+ // Store the "shift" most significant bits of scratch in the least
+ // signficant bits (i.e., shift down by (32-shift)).
+ __ rsb(scratch2, left_shift, Operand(32));
+ Register right_shift = scratch2;
+ __ mov(scratch1, Operand(scratch1, LSR, right_shift));
+
+ __ bind(&loop);
+ __ ldr(scratch3, MemOperand(src, 4, PostIndex));
+ __ sub(scratch5, limit, Operand(dest));
+ __ orr(scratch1, scratch1, Operand(scratch3, LSL, left_shift));
+ __ str(scratch1, MemOperand(dest, 4, PostIndex));
+ __ mov(scratch1, Operand(scratch3, LSR, right_shift));
+ // Loop if four or more bytes left to copy.
+ // Compare to eight, because we did the subtract before increasing dst.
+ __ sub(scratch5, scratch5, Operand(8), SetCC);
+ __ b(ge, &loop);
+ }
+ // There is now between zero and three bytes left to copy (negative that
+ // number is in scratch5), and between one and three bytes already read into
+ // scratch1 (eight times that number in scratch4). We may have read past
+ // the end of the string, but because objects are aligned, we have not read
+ // past the end of the object.
+ // Find the minimum of remaining characters to move and preloaded characters
+ // and write those as bytes.
+ __ add(scratch5, scratch5, Operand(4), SetCC);
+ __ b(eq, &done);
+ __ cmp(scratch4, Operand(scratch5, LSL, 3), ne);
+ // Move minimum of bytes read and bytes left to copy to scratch4.
+ __ mov(scratch5, Operand(scratch4, LSR, 3), LeaveCC, lt);
+ // Between one and three (value in scratch5) characters already read into
+ // scratch ready to write.
+ __ cmp(scratch5, Operand(2));
+ __ strb(scratch1, MemOperand(dest, 1, PostIndex));
+ __ mov(scratch1, Operand(scratch1, LSR, 8), LeaveCC, ge);
+ __ strb(scratch1, MemOperand(dest, 1, PostIndex), ge);
+ __ mov(scratch1, Operand(scratch1, LSR, 8), LeaveCC, gt);
+ __ strb(scratch1, MemOperand(dest, 1, PostIndex), gt);
+ // Copy any remaining bytes.
+ __ b(&byte_loop);
+
+ // Simple loop.
+ // Copy words from src to dst, until less than four bytes left.
+ // Both src and dest are word aligned.
+ __ bind(&simple_loop);
+ {
+ Label loop;
+ __ bind(&loop);
+ __ ldr(scratch1, MemOperand(src, 4, PostIndex));
+ __ sub(scratch3, limit, Operand(dest));
+ __ str(scratch1, MemOperand(dest, 4, PostIndex));
+ // Compare to 8, not 4, because we do the substraction before increasing
+ // dest.
+ __ cmp(scratch3, Operand(8));
+ __ b(ge, &loop);
+ }
+
+ // Copy bytes from src to dst until dst hits limit.
+ __ bind(&byte_loop);
+ __ cmp(dest, Operand(limit));
+ __ ldrb(scratch1, MemOperand(src, 1, PostIndex), lt);
+ __ b(ge, &done);
+ __ strb(scratch1, MemOperand(dest, 1, PostIndex));
+ __ b(&byte_loop);
+
+ __ bind(&done);
+}
+
+
+void SubStringStub::Generate(MacroAssembler* masm) {
+ Label runtime;
+
+ // Stack frame on entry.
+ // lr: return address
+ // sp[0]: to
+ // sp[4]: from
+ // sp[8]: string
+
+ // This stub is called from the native-call %_SubString(...), so
+ // nothing can be assumed about the arguments. It is tested that:
+ // "string" is a sequential string,
+ // both "from" and "to" are smis, and
+ // 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;
+
+
+ // Check bounds and smi-ness.
+ __ ldr(r7, MemOperand(sp, kToOffset));
+ __ ldr(r6, MemOperand(sp, kFromOffset));
+ ASSERT_EQ(0, kSmiTag);
+ ASSERT_EQ(1, kSmiTagSize + kSmiShiftSize);
+ // I.e., arithmetic shift right by one un-smi-tags.
+ __ mov(r2, Operand(r7, ASR, 1), SetCC);
+ __ mov(r3, Operand(r6, ASR, 1), SetCC, cc);
+ // If either r2 or r6 had the smi tag bit set, then carry is set now.
+ __ b(cs, &runtime); // Either "from" or "to" is not a smi.
+ __ b(mi, &runtime); // From is negative.
+
+ __ sub(r2, r2, Operand(r3), SetCC);
+ __ b(mi, &runtime); // Fail if from > to.
+ // Handle sub-strings of length 2 and less in the runtime system.
+ __ cmp(r2, Operand(2));
+ __ b(le, &runtime);
+
+ // r2: length
+ // r6: from (smi)
+ // r7: to (smi)
+
+ // Make sure first argument is a sequential (or flat) string.
+ __ ldr(r5, MemOperand(sp, kStringOffset));
+ ASSERT_EQ(0, kSmiTag);
+ __ tst(r5, Operand(kSmiTagMask));
+ __ b(eq, &runtime);
+ Condition is_string = masm->IsObjectStringType(r5, r1);
+ __ b(NegateCondition(is_string), &runtime);
+
+ // r1: instance type
+ // r2: length
+ // r5: string
+ // r6: from (smi)
+ // r7: to (smi)
+ Label seq_string;
+ __ and_(r4, r1, Operand(kStringRepresentationMask));
+ ASSERT(kSeqStringTag < kConsStringTag);
+ ASSERT(kExternalStringTag > kConsStringTag);
+ __ cmp(r4, Operand(kConsStringTag));
+ __ b(gt, &runtime); // External strings go to runtime.
+ __ b(lt, &seq_string); // Sequential strings are handled directly.
+
+ // 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).
+ __ ldr(r5, FieldMemOperand(r5, ConsString::kFirstOffset));
+ __ ldr(r4, FieldMemOperand(r5, HeapObject::kMapOffset));
+ __ ldrb(r1, FieldMemOperand(r4, Map::kInstanceTypeOffset));
+ __ tst(r1, Operand(kStringRepresentationMask));
+ ASSERT_EQ(0, kSeqStringTag);
+ __ b(ne, &runtime); // Cons and External strings go to runtime.
+
+ // Definitly a sequential string.
+ __ bind(&seq_string);
+
+ // r1: instance type.
+ // r2: length
+ // r5: string
+ // r6: from (smi)
+ // r7: to (smi)
+ __ ldr(r4, FieldMemOperand(r5, String::kLengthOffset));
+ __ cmp(r4, Operand(r7, ASR, 1));
+ __ b(lt, &runtime); // Fail if to > length.
+
+ // r1: instance type.
+ // r2: result string length.
+ // r5: string.
+ // r6: from offset (smi)
+ // Check for flat ascii string.
+ Label non_ascii_flat;
+ __ tst(r1, Operand(kStringEncodingMask));
+ ASSERT_EQ(0, kTwoByteStringTag);
+ __ b(eq, &non_ascii_flat);
+
+ // Allocate the result.
+ __ AllocateAsciiString(r0, r2, r3, r4, r1, &runtime);
+
+ // r0: result string.
+ // r2: result string length.
+ // r5: string.
+ // r6: from offset (smi)
+ // Locate first character of result.
+ __ add(r1, r0, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+ // Locate 'from' character of string.
+ __ add(r5, r5, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
+ __ add(r5, r5, Operand(r6, ASR, 1));
+
+ // r0: result string.
+ // r1: first character of result string.
+ // r2: result string length.
+ // r5: first character of sub string to copy.
+ ASSERT_EQ(0, SeqAsciiString::kHeaderSize & kObjectAlignmentMask);
+ GenerateCopyCharactersLong(masm, r1, r5, r2, r3, r4, r6, r7, r9,
+ COPY_ASCII | DEST_ALWAYS_ALIGNED);
+ __ IncrementCounter(&Counters::sub_string_native, 1, r3, r4);
+ __ add(sp, sp, Operand(3 * kPointerSize));
+ __ Ret();
+
+ __ bind(&non_ascii_flat);
+ // r2: result string length.
+ // r5: string.
+ // r6: from offset (smi)
+ // Check for flat two byte string.
+
+ // Allocate the result.
+ __ AllocateTwoByteString(r0, r2, r1, r3, r4, &runtime);
+
+ // r0: result string.
+ // r2: result string length.
+ // r5: string.
+ // Locate first character of result.
+ __ add(r1, r0, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+ // Locate 'from' character of string.
+ __ add(r5, r5, Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+ // As "from" is a smi it is 2 times the value which matches the size of a two
+ // byte character.
+ __ add(r5, r5, Operand(r6));
+
+ // r0: result string.
+ // r1: first character of result.
+ // r2: result length.
+ // r5: first character of string to copy.
+ ASSERT_EQ(0, SeqTwoByteString::kHeaderSize & kObjectAlignmentMask);
+ GenerateCopyCharactersLong(masm, r1, r5, r2, r3, r4, r6, r7, r9,
+ DEST_ALWAYS_ALIGNED);
+ __ IncrementCounter(&Counters::sub_string_native, 1, r3, r4);
+ __ add(sp, sp, Operand(3 * kPointerSize));
+ __ Ret();
+
+ // Just jump to runtime to create the sub string.
+ __ bind(&runtime);
+ __ TailCallRuntime(ExternalReference(Runtime::kSubString), 3, 1);
+}
void StringCompareStub::GenerateCompareFlatAsciiStrings(MacroAssembler* masm,
void MacroAssembler::LoadRoot(Register destination,
Heap::RootListIndex index,
Condition cond) {
- ldr(destination, MemOperand(r10, index << kPointerSizeLog2), cond);
+ ldr(destination, MemOperand(roots, index << kPointerSizeLog2), cond);
}
}
+void MacroAssembler::AllocateTwoByteString(Register result,
+ Register length,
+ Register scratch1,
+ Register scratch2,
+ Register scratch3,
+ Label* gc_required) {
+ // Calculate the number of bytes needed for the characters in the string while
+ // observing object alignment.
+ ASSERT((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
+ mov(scratch1, Operand(length, LSL, 1)); // Length in bytes, not chars.
+ add(scratch1, scratch1,
+ Operand(kObjectAlignmentMask + SeqTwoByteString::kHeaderSize));
+ // AllocateInNewSpace expects the size in words, so we can round down
+ // to kObjectAlignment and divide by kPointerSize in the same shift.
+ ASSERT_EQ(kPointerSize, kObjectAlignmentMask + 1);
+ mov(scratch1, Operand(scratch1, ASR, kPointerSizeLog2));
+
+ // Allocate two-byte string in new space.
+ AllocateInNewSpace(scratch1,
+ result,
+ scratch2,
+ scratch3,
+ gc_required,
+ TAG_OBJECT);
+
+ // Set the map, length and hash field.
+ LoadRoot(scratch1, Heap::kStringMapRootIndex);
+ str(length, FieldMemOperand(result, String::kLengthOffset));
+ str(scratch1, FieldMemOperand(result, HeapObject::kMapOffset));
+ mov(scratch2, Operand(String::kEmptyHashField));
+ str(scratch2, FieldMemOperand(result, String::kHashFieldOffset));
+}
+
+
+void MacroAssembler::AllocateAsciiString(Register result,
+ Register length,
+ Register scratch1,
+ Register scratch2,
+ Register scratch3,
+ Label* gc_required) {
+ // Calculate the number of bytes needed for the characters in the string while
+ // observing object alignment.
+ ASSERT((SeqAsciiString::kHeaderSize & kObjectAlignmentMask) == 0);
+ ASSERT(kCharSize == 1);
+ add(scratch1, length,
+ Operand(kObjectAlignmentMask + SeqAsciiString::kHeaderSize));
+ // AllocateInNewSpace expects the size in words, so we can round down
+ // to kObjectAlignment and divide by kPointerSize in the same shift.
+ ASSERT_EQ(kPointerSize, kObjectAlignmentMask + 1);
+ mov(scratch1, Operand(scratch1, ASR, kPointerSizeLog2));
+
+ // Allocate ASCII string in new space.
+ AllocateInNewSpace(scratch1,
+ result,
+ scratch2,
+ scratch3,
+ gc_required,
+ TAG_OBJECT);
+
+ // Set the map, length and hash field.
+ LoadRoot(scratch1, Heap::kAsciiStringMapRootIndex);
+ mov(scratch1, Operand(Factory::ascii_string_map()));
+ str(length, FieldMemOperand(result, String::kLengthOffset));
+ str(scratch1, FieldMemOperand(result, HeapObject::kMapOffset));
+ mov(scratch2, Operand(String::kEmptyHashField));
+ str(scratch2, FieldMemOperand(result, String::kHashFieldOffset));
+}
+
+
void MacroAssembler::CompareObjectType(Register function,
Register map,
Register type_reg,
projects / platform / upstream / v8.git / commitdiff