Improve mirror::String implementation.
Explicitly use string compression to optimize uses of
String::CharAt() in string.cc similarly to
https://android-review.googlesource.com/1446657 .
Move string content initialization to pre-fence visitor.
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 169674485
Change-Id: I3dc453ce995d09f996610a1eba5060bacbe0d498
diff --git a/runtime/mirror/string.cc b/runtime/mirror/string.cc
index 2dfb57f..72d82f1 100644
--- a/runtime/mirror/string.cc
+++ b/runtime/mirror/string.cc
@@ -80,35 +80,36 @@
(src->IsCompressed() || (!IsASCII(old_c) && AllASCIIExcept(src->value_, length, old_c)));
gc::AllocatorType allocator_type = Runtime::Current()->GetHeap()->GetCurrentAllocator();
const int32_t length_with_flag = String::GetFlaggedCount(length, compressible);
- SetStringCountVisitor visitor(length_with_flag);
- ObjPtr<String> string = Alloc(self, length_with_flag, allocator_type, visitor);
- if (UNLIKELY(string == nullptr)) {
- return nullptr;
- }
- if (compressible) {
- auto replace = [old_c, new_c](uint16_t c) {
- return dchecked_integral_cast<uint8_t>((old_c != c) ? c : new_c);
- };
- uint8_t* out = string->value_compressed_;
- if (LIKELY(src->IsCompressed())) { // LIKELY(compressible == src->IsCompressed())
- std::transform(src->value_compressed_, src->value_compressed_ + length, out, replace);
+
+ auto visitor = [=](ObjPtr<Object> obj, size_t usable_size) REQUIRES_SHARED(Locks::mutator_lock_) {
+ SetStringCountVisitor set_string_count_visitor(length_with_flag);
+ set_string_count_visitor(obj, usable_size);
+ ObjPtr<String> new_string = obj->AsString();
+ if (compressible) {
+ auto replace = [old_c, new_c](uint16_t c) {
+ return dchecked_integral_cast<uint8_t>((old_c != c) ? c : new_c);
+ };
+ uint8_t* out = new_string->value_compressed_;
+ if (LIKELY(src->IsCompressed())) { // LIKELY(compressible == src->IsCompressed())
+ std::transform(src->value_compressed_, src->value_compressed_ + length, out, replace);
+ } else {
+ std::transform(src->value_, src->value_ + length, out, replace);
+ }
+ DCHECK(kUseStringCompression && AllASCII(out, length));
} else {
- std::transform(src->value_, src->value_ + length, out, replace);
+ auto replace = [old_c, new_c](uint16_t c) {
+ return (old_c != c) ? c : new_c;
+ };
+ uint16_t* out = new_string->value_;
+ if (UNLIKELY(src->IsCompressed())) { // LIKELY(compressible == src->IsCompressed())
+ std::transform(src->value_compressed_, src->value_compressed_ + length, out, replace);
+ } else {
+ std::transform(src->value_, src->value_ + length, out, replace);
+ }
+ DCHECK(!kUseStringCompression || !AllASCII(out, length));
}
- DCHECK(kUseStringCompression && AllASCII(out, length));
- } else {
- auto replace = [old_c, new_c](uint16_t c) {
- return (old_c != c) ? c : new_c;
- };
- uint16_t* out = string->value_;
- if (UNLIKELY(src->IsCompressed())) { // LIKELY(compressible == src->IsCompressed())
- std::transform(src->value_compressed_, src->value_compressed_ + length, out, replace);
- } else {
- std::transform(src->value_, src->value_ + length, out, replace);
- }
- DCHECK(!kUseStringCompression || !AllASCII(out, length));
- }
- return string;
+ };
+ return Alloc(self, length_with_flag, allocator_type, visitor);
}
ObjPtr<String> String::AllocFromStrings(Thread* self,
@@ -121,33 +122,35 @@
(string->IsCompressed() && string2->IsCompressed());
const int32_t length_with_flag = String::GetFlaggedCount(length + length2, compressible);
- SetStringCountVisitor visitor(length_with_flag);
- ObjPtr<String> new_string = Alloc(self, length_with_flag, allocator_type, visitor);
- if (UNLIKELY(new_string == nullptr)) {
- return nullptr;
- }
- if (compressible) {
- uint8_t* new_value = new_string->GetValueCompressed();
- memcpy(new_value, string->GetValueCompressed(), length * sizeof(uint8_t));
- memcpy(new_value + length, string2->GetValueCompressed(), length2 * sizeof(uint8_t));
- } else {
- uint16_t* new_value = new_string->GetValue();
- if (string->IsCompressed()) {
- for (int i = 0; i < length; ++i) {
- new_value[i] = string->CharAt(i);
- }
+ auto visitor = [=](ObjPtr<Object> obj, size_t usable_size) REQUIRES_SHARED(Locks::mutator_lock_) {
+ SetStringCountVisitor set_string_count_visitor(length_with_flag);
+ set_string_count_visitor(obj, usable_size);
+ ObjPtr<String> new_string = obj->AsString();
+ if (compressible) {
+ uint8_t* new_value = new_string->GetValueCompressed();
+ memcpy(new_value, string->GetValueCompressed(), length * sizeof(uint8_t));
+ memcpy(new_value + length, string2->GetValueCompressed(), length2 * sizeof(uint8_t));
} else {
- memcpy(new_value, string->GetValue(), length * sizeof(uint16_t));
- }
- if (string2->IsCompressed()) {
- for (int i = 0; i < length2; ++i) {
- new_value[i+length] = string2->CharAt(i);
+ uint16_t* new_value = new_string->GetValue();
+ if (string->IsCompressed()) {
+ const uint8_t* value = string->GetValueCompressed();
+ for (int i = 0; i < length; ++i) {
+ new_value[i] = value[i];
+ }
+ } else {
+ memcpy(new_value, string->GetValue(), length * sizeof(uint16_t));
}
- } else {
- memcpy(new_value + length, string2->GetValue(), length2 * sizeof(uint16_t));
+ if (string2->IsCompressed()) {
+ const uint8_t* value2 = string->GetValueCompressed();
+ for (int i = 0; i < length2; ++i) {
+ new_value[i+length] = value2[i];
+ }
+ } else {
+ memcpy(new_value + length, string2->GetValue(), length2 * sizeof(uint16_t));
+ }
}
- }
- return new_string;
+ };
+ return Alloc(self, length_with_flag, allocator_type, visitor);
}
ObjPtr<String> String::AllocFromUtf16(Thread* self,
@@ -158,20 +161,21 @@
const bool compressible = kUseStringCompression &&
String::AllASCII<uint16_t>(utf16_data_in, utf16_length);
int32_t length_with_flag = String::GetFlaggedCount(utf16_length, compressible);
- SetStringCountVisitor visitor(length_with_flag);
- ObjPtr<String> string = Alloc(self, length_with_flag, allocator_type, visitor);
- if (UNLIKELY(string == nullptr)) {
- return nullptr;
- }
- if (compressible) {
- for (int i = 0; i < utf16_length; ++i) {
- string->GetValueCompressed()[i] = static_cast<uint8_t>(utf16_data_in[i]);
+
+ auto visitor = [=](ObjPtr<Object> obj, size_t usable_size) REQUIRES_SHARED(Locks::mutator_lock_) {
+ SetStringCountVisitor set_string_count_visitor(length_with_flag);
+ set_string_count_visitor(obj, usable_size);
+ ObjPtr<String> new_string = obj->AsString();
+ if (compressible) {
+ uint8_t* value = new_string->GetValueCompressed();
+ for (int i = 0; i < utf16_length; ++i) {
+ value[i] = static_cast<uint8_t>(utf16_data_in[i]);
+ }
+ } else {
+ memcpy(new_string->GetValue(), utf16_data_in, utf16_length * sizeof(uint16_t));
}
- } else {
- uint16_t* array = string->GetValue();
- memcpy(array, utf16_data_in, utf16_length * sizeof(uint16_t));
- }
- return string;
+ };
+ return Alloc(self, length_with_flag, allocator_type, visitor);
}
ObjPtr<String> String::AllocFromModifiedUtf8(Thread* self, const char* utf) {
@@ -193,19 +197,20 @@
int32_t utf8_length) {
gc::AllocatorType allocator_type = Runtime::Current()->GetHeap()->GetCurrentAllocator();
const bool compressible = kUseStringCompression && (utf16_length == utf8_length);
- const int32_t utf16_length_with_flag = String::GetFlaggedCount(utf16_length, compressible);
- SetStringCountVisitor visitor(utf16_length_with_flag);
- ObjPtr<String> string = Alloc(self, utf16_length_with_flag, allocator_type, visitor);
- if (UNLIKELY(string == nullptr)) {
- return nullptr;
- }
- if (compressible) {
- memcpy(string->GetValueCompressed(), utf8_data_in, utf16_length * sizeof(uint8_t));
- } else {
- uint16_t* utf16_data_out = string->GetValue();
- ConvertModifiedUtf8ToUtf16(utf16_data_out, utf16_length, utf8_data_in, utf8_length);
- }
- return string;
+ const int32_t length_with_flag = String::GetFlaggedCount(utf16_length, compressible);
+
+ auto visitor = [=](ObjPtr<Object> obj, size_t usable_size) REQUIRES_SHARED(Locks::mutator_lock_) {
+ SetStringCountVisitor set_string_count_visitor(length_with_flag);
+ set_string_count_visitor(obj, usable_size);
+ ObjPtr<String> new_string = obj->AsString();
+ if (compressible) {
+ memcpy(new_string->GetValueCompressed(), utf8_data_in, utf16_length * sizeof(uint8_t));
+ } else {
+ uint16_t* utf16_data_out = new_string->GetValue();
+ ConvertModifiedUtf8ToUtf16(utf16_data_out, utf16_length, utf8_data_in, utf8_length);
+ }
+ };
+ return Alloc(self, length_with_flag, allocator_type, visitor);
}
bool String::Equals(ObjPtr<String> that) {
@@ -215,23 +220,27 @@
} else if (that == nullptr) {
// Null isn't an instanceof anything
return false;
- } else if (this->GetLength() != that->GetLength()) {
- // Quick length inequality test
+ } else if (this->GetCount() != that->GetCount()) {
+ // Quick length and compression inequality test
return false;
} else {
// Note: don't short circuit on hash code as we're presumably here as the
// hash code was already equal
- for (int32_t i = 0; i < that->GetLength(); ++i) {
- if (this->CharAt(i) != that->CharAt(i)) {
- return false;
- }
+ if (this->IsCompressed()) {
+ return memcmp(this->GetValueCompressed(), that->GetValueCompressed(), this->GetLength()) == 0;
+ } else {
+ return memcmp(this->GetValue(), that->GetValue(), sizeof(uint16_t) * this->GetLength()) == 0;
}
- return true;
}
}
bool String::Equals(const char* modified_utf8) {
const int32_t length = GetLength();
+ if (IsCompressed()) {
+ return strlen(modified_utf8) == dchecked_integral_cast<uint32_t>(length) &&
+ memcmp(modified_utf8, GetValueCompressed(), length) == 0;
+ }
+ const uint16_t* value = GetValue();
int32_t i = 0;
while (i < length) {
const uint32_t ch = GetUtf16FromUtf8(&modified_utf8);
@@ -239,7 +248,7 @@
return false;
}
- if (GetLeadingUtf16Char(ch) != CharAt(i++)) {
+ if (GetLeadingUtf16Char(ch) != value[i++]) {
return false;
}
@@ -249,7 +258,7 @@
return false;
}
- if (CharAt(i++) != trailing) {
+ if (value[i++] != trailing) {
return false;
}
}
@@ -259,17 +268,14 @@
// Create a modified UTF-8 encoded std::string from a java/lang/String object.
std::string String::ToModifiedUtf8() {
- size_t byte_count = GetUtfLength();
- std::string result(byte_count, static_cast<char>(0));
if (IsCompressed()) {
- for (size_t i = 0; i < byte_count; ++i) {
- result[i] = static_cast<char>(CharAt(i));
- }
+ return std::string(reinterpret_cast<const char*>(GetValueCompressed()), GetLength());
} else {
- const uint16_t* chars = GetValue();
- ConvertUtf16ToModifiedUtf8(&result[0], byte_count, chars, GetLength());
+ size_t byte_count = GetUtfLength();
+ std::string result(byte_count, static_cast<char>(0));
+ ConvertUtf16ToModifiedUtf8(&result[0], byte_count, GetValue(), GetLength());
+ return result;
}
- return result;
}
int32_t String::CompareTo(ObjPtr<String> rhs) {
@@ -320,8 +326,10 @@
if (result != nullptr) {
if (h_this->IsCompressed()) {
int32_t length = h_this->GetLength();
+ const uint8_t* src = h_this->GetValueCompressed();
+ uint16_t* dest = result->GetData();
for (int i = 0; i < length; ++i) {
- result->GetData()[i] = h_this->CharAt(i);
+ dest[i] = src[i];
}
} else {
memcpy(result->GetData(), h_this->GetValue(), h_this->GetLength() * sizeof(uint16_t));
@@ -334,13 +342,16 @@
void String::GetChars(int32_t start, int32_t end, Handle<CharArray> array, int32_t index) {
uint16_t* data = array->GetData() + index;
+ DCHECK_LE(start, end);
+ int32_t length = end - start;
if (IsCompressed()) {
- for (int i = start; i < end; ++i) {
- data[i-start] = CharAt(i);
+ const uint8_t* value = GetValueCompressed() + start;
+ for (int i = 0; i < length; ++i) {
+ data[i] = value[i];
}
} else {
uint16_t* value = GetValue() + start;
- memcpy(data, value, (end - start) * sizeof(uint16_t));
+ memcpy(data, value, length * sizeof(uint16_t));
}
}