Change string compression encoding.
Encode the string compression flag as the least significant
bit of the "count" field, with 0 meaning compressed and 1
meaning uncompressed.
The main vdex file is a tiny bit larger (+28B for prebuilt
boot images, +32 for on-device built images) and the oat
file sizes change. Measured on Nexus 9, AOSP ToT, these
changes are insignificant when string compression is
disabled (-200B for the 32-bit boot*.oat for prebuilt boot
image, -4KiB when built on the device attributable to
rounding, -16B for 64-bit boot*.oat for prebuilt boot image,
no change when built on device) but with string compression
enabled we get significant differences:
prebuilt multi-part boot image:
- 32-bit boot*.oat: -28KiB
- 64-bit boot*.oat: -24KiB
on-device built single boot image:
- 32-bit boot.oat: -32KiB
- 64-bit boot.oat: -28KiB
The boot image oat file overhead for string compression:
prebuilt multi-part boot image:
- 32-bit boot*.oat: before: ~80KiB after: ~52KiB
- 64-bit boot*.oat: before: ~116KiB after: ~92KiB
on-device built single boot image:
- 32-bit boot.oat: before: 92KiB after: 60KiB
- 64-bit boot.oat: before: 116KiB after: 92KiB
The differences in the SplitStringBenchmark seem to be lost
in the noise.
Test: Run ART test suite on host and Nexus 9 with Optimizing.
Test: Run ART test suite on host and Nexus 9 with interpreter.
Test: All of the above with string compression enabled.
Bug: 31040547
Change-Id: I7570c2b700f1a31004a2d3c18b1cc30046d35a74
diff --git a/runtime/interpreter/unstarted_runtime.cc b/runtime/interpreter/unstarted_runtime.cc
index 6bf7e15..2257fd6 100644
--- a/runtime/interpreter/unstarted_runtime.cc
+++ b/runtime/interpreter/unstarted_runtime.cc
@@ -1097,10 +1097,12 @@
return;
}
DCHECK_GE(start, 0);
- DCHECK_GE(end, string->GetLength());
+ DCHECK_LE(start, end);
+ DCHECK_LE(end, string->GetLength());
StackHandleScope<1> hs(self);
Handle<mirror::CharArray> h_char_array(
hs.NewHandle(shadow_frame->GetVRegReference(arg_offset + 3)->AsCharArray()));
+ DCHECK_GE(index, 0);
DCHECK_LE(index, h_char_array->GetLength());
DCHECK_LE(end - start, h_char_array->GetLength() - index);
string->GetChars(start, end, h_char_array, index);