ART: Optimize StringBuilder append pattern.
Recognize appending with StringBuilder and replace the
entire expression with a runtime call that perfoms the
append in a more efficient manner.
For now, require the entire pattern to be in a single block
and be very strict about the StringBuilder environment uses.
Also, do not accept StringBuilder/char[]/Object/float/double
arguments as they throw non-OOME exceptions and/or require a
call from the entrypoint back to a helper function in Java;
these shall be implemented later.
Boot image size for aosp_taimen-userdebug:
- before:
arm/boot*.oat: 19653872
arm64/boot*.oat: 23292784
oat/arm64/services.odex: 22408664
- after:
arm/boot*.oat: 19432184 (-216KiB)
arm64/boot*.oat: 22992488 (-293KiB)
oat/arm64/services.odex: 22376776 (-31KiB)
Note that const-string in compiled boot image methods cannot
throw, but for apps it can and therefore its environment can
prevent the optimization for apps. We could implement either
a simple carve-out for const-string or generic environment
pruning to allow this pattern to be applied more often.
Results for the new StringBuilderAppendBenchmark on taimen:
timeAppendLongStrings: ~700ns -> ~200ns
timeAppendStringAndInt: ~220ns -> ~140ns
timeAppendStrings: ~200ns -> 130ns
Bug: 19575890
Test: 697-checker-string-append
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: aosp_taimen-userdebug boots.
Test: run-gtests.sh
Test: testrunner.py --target --optimizing
Test: vogar --benchmark art/benchmark/stringbuilder-append/src/StringBuilderAppendBenchmark.java
Change-Id: I51789bf299f5219f68ada4c077b6a1d3fe083964
diff --git a/runtime/entrypoints/quick/quick_default_init_entrypoints.h b/runtime/entrypoints/quick/quick_default_init_entrypoints.h
index ce12fde..f5bb5a3 100644
--- a/runtime/entrypoints/quick/quick_default_init_entrypoints.h
+++ b/runtime/entrypoints/quick/quick_default_init_entrypoints.h
@@ -121,6 +121,9 @@
// Deoptimize
qpoints->pDeoptimize = art_quick_deoptimize_from_compiled_code;
+
+ // StringBuilder append
+ qpoints->pStringBuilderAppend = art_quick_string_builder_append;
}
} // namespace art
diff --git a/runtime/entrypoints/quick/quick_entrypoints.h b/runtime/entrypoints/quick/quick_entrypoints.h
index 243f7ec..954450f 100644
--- a/runtime/entrypoints/quick/quick_entrypoints.h
+++ b/runtime/entrypoints/quick/quick_entrypoints.h
@@ -34,6 +34,7 @@
class Class;
template<class MirrorType> class CompressedReference;
class Object;
+class String;
} // namespace mirror
class ArtMethod;
@@ -78,6 +79,11 @@
jobject locked, Thread* self)
NO_THREAD_SAFETY_ANALYSIS HOT_ATTR;
+extern "C" mirror::String* artStringBuilderAppend(uint32_t format,
+ const uint32_t* args,
+ Thread* self)
+ REQUIRES_SHARED(Locks::mutator_lock_) HOT_ATTR;
+
extern void ReadBarrierJni(mirror::CompressedReference<mirror::Object>* handle_on_stack,
Thread* self)
NO_THREAD_SAFETY_ANALYSIS HOT_ATTR;
diff --git a/runtime/entrypoints/quick/quick_entrypoints_list.h b/runtime/entrypoints/quick/quick_entrypoints_list.h
index 42b680e..21e248c 100644
--- a/runtime/entrypoints/quick/quick_entrypoints_list.h
+++ b/runtime/entrypoints/quick/quick_entrypoints_list.h
@@ -169,6 +169,8 @@
V(NewStringFromStringBuffer, void, void) \
V(NewStringFromStringBuilder, void, void) \
\
+ V(StringBuilderAppend, void*, uint32_t) \
+\
V(ReadBarrierJni, void, mirror::CompressedReference<mirror::Object>*, Thread*) \
V(ReadBarrierMarkReg00, mirror::Object*, mirror::Object*) \
V(ReadBarrierMarkReg01, mirror::Object*, mirror::Object*) \
diff --git a/runtime/entrypoints/quick/quick_string_builder_append_entrypoints.cc b/runtime/entrypoints/quick/quick_string_builder_append_entrypoints.cc
new file mode 100644
index 0000000..9afaf43
--- /dev/null
+++ b/runtime/entrypoints/quick/quick_string_builder_append_entrypoints.cc
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "quick_entrypoints.h"
+
+#include "string_builder_append.h"
+#include "obj_ptr-inl.h"
+
+namespace art {
+
+extern "C" mirror::String* artStringBuilderAppend(uint32_t format,
+ const uint32_t* args,
+ Thread* self) {
+ return StringBuilderAppend::AppendF(format, args, self).Ptr();
+}
+
+} // namespace art
diff --git a/runtime/entrypoints/runtime_asm_entrypoints.h b/runtime/entrypoints/runtime_asm_entrypoints.h
index fa287cb..3f4e91e 100644
--- a/runtime/entrypoints/runtime_asm_entrypoints.h
+++ b/runtime/entrypoints/runtime_asm_entrypoints.h
@@ -87,6 +87,8 @@
return reinterpret_cast<const void*>(art_quick_instrumentation_exit);
}
+extern "C" void* art_quick_string_builder_append(uint32_t format);
+
} // namespace art
#endif // ART_RUNTIME_ENTRYPOINTS_RUNTIME_ASM_ENTRYPOINTS_H_