ART: Compress LengthPrefixedArray on 32-bit targets.
Previously, the LengthPrefixedArray<ArtMethod> on 32-bit
targets contained a 64-bit length field followed by the
ArtMethod elements with size only a multiple of 4, not 8.
Consequently, an odd-length array broke the alignment for
the following array which would have the 64-bit length
placed at an unaligned address.
To fix that, we make the length field 32-bit and explicitly
pass the alignment information to the LengthPrefixedArray.
This also makes the 32-bit boot image a bit smaller.
On Nexus 5, AOSP, ToT, the field section is 11528B smaller
and the method section is 21036B smaller. 64-bit targets
should see the same savings for the field section but no
difference for the methods section.
Change-Id: I3e03e7b94129025c8a1c117c27645a34dec516d2
diff --git a/compiler/image_writer.h b/compiler/image_writer.h
index f4e10cc..c8aa82d 100644
--- a/compiler/image_writer.h
+++ b/compiler/image_writer.h
@@ -54,7 +54,7 @@
quick_imt_conflict_trampoline_offset_(0), quick_resolution_trampoline_offset_(0),
quick_to_interpreter_bridge_offset_(0), compile_pic_(compile_pic),
target_ptr_size_(InstructionSetPointerSize(compiler_driver_.GetInstructionSet())),
- bin_slot_sizes_(), bin_slot_previous_sizes_(), bin_slot_count_(),
+ bin_slot_sizes_(), bin_slot_offsets_(), bin_slot_count_(),
intern_table_bytes_(0u), image_method_array_(ImageHeader::kImageMethodsCount),
dirty_methods_(0u), clean_methods_(0u) {
CHECK_NE(image_begin, 0U);
@@ -359,7 +359,7 @@
// Bin slot tracking for dirty object packing
size_t bin_slot_sizes_[kBinSize]; // Number of bytes in a bin
- size_t bin_slot_previous_sizes_[kBinSize]; // Number of bytes in previous bins.
+ size_t bin_slot_offsets_[kBinSize]; // Number of bytes in previous bins.
size_t bin_slot_count_[kBinSize]; // Number of objects in a bin
// Cached size of the intern table for when we allocate memory.