ART: Fast copy stack mask
StackMap::SetStackMask will currently copy a BitVector into a Memory-
Region bit by bit. This patch adds a new function for copying the data
with memcpy.
This is resubmission of CL I28d45a590b35a4a854cca2f57db864cf8a081487
but with a fix for a broken test which it revealed.
Change-Id: Ib65aa614d3ab7b5c99c6719fdc8e436466a4213d
diff --git a/compiler/optimizing/stack_map_test.cc b/compiler/optimizing/stack_map_test.cc
index 98e14ea..666fb60 100644
--- a/compiler/optimizing/stack_map_test.cc
+++ b/compiler/optimizing/stack_map_test.cc
@@ -136,7 +136,7 @@
ArenaBitVector sp_mask2(&arena, 0, true);
sp_mask2.SetBit(3);
- sp_mask1.SetBit(8);
+ sp_mask2.SetBit(8);
stream.BeginStackMapEntry(1, 128, 0xFF, &sp_mask2, number_of_dex_registers, 0);
stream.AddDexRegisterEntry(Kind::kInRegister, 18); // Short location.
stream.AddDexRegisterEntry(Kind::kInFpuRegister, 3); // Short location.
@@ -148,7 +148,7 @@
stream.FillIn(region);
CodeInfo code_info(region);
- ASSERT_EQ(1u, code_info.GetStackMaskSize());
+ ASSERT_EQ(2u, code_info.GetStackMaskSize());
ASSERT_EQ(2u, code_info.GetNumberOfStackMaps());
uint32_t number_of_location_catalog_entries =
diff --git a/runtime/base/bit_vector.h b/runtime/base/bit_vector.h
index 17835f5..afa8dc1 100644
--- a/runtime/base/bit_vector.h
+++ b/runtime/base/bit_vector.h
@@ -21,6 +21,7 @@
#include <iterator>
#include "base/bit_utils.h"
+#include "globals.h"
namespace art {
@@ -229,6 +230,19 @@
// Number of bits set in range [0, end) in storage. (No range check.)
static uint32_t NumSetBits(const uint32_t* storage, uint32_t end);
+ // Fill given memory region with the contents of the vector and zero padding.
+ void CopyTo(void* dst, size_t len) const {
+ DCHECK_LE(static_cast<size_t>(GetHighestBitSet() + 1), len * kBitsPerByte);
+ size_t vec_len = GetSizeOf();
+ if (vec_len < len) {
+ void* dst_padding = reinterpret_cast<uint8_t*>(dst) + vec_len;
+ memcpy(dst, storage_, vec_len);
+ memset(dst_padding, 0, len - vec_len);
+ } else {
+ memcpy(dst, storage_, len);
+ }
+ }
+
void Dump(std::ostream& os, const char* prefix) const;
private:
diff --git a/runtime/base/bit_vector_test.cc b/runtime/base/bit_vector_test.cc
index c51b9b0..19c01f2 100644
--- a/runtime/base/bit_vector_test.cc
+++ b/runtime/base/bit_vector_test.cc
@@ -211,4 +211,62 @@
}
}
+TEST(BitVector, CopyTo) {
+ {
+ // Test copying an empty BitVector. Padding should fill `buf` with zeroes.
+ BitVector bv(0, true, Allocator::GetMallocAllocator());
+ uint32_t buf;
+
+ bv.CopyTo(&buf, sizeof(buf));
+ EXPECT_EQ(0u, bv.GetSizeOf());
+ EXPECT_EQ(0u, buf);
+ }
+
+ {
+ // Test copying when `bv.storage_` and `buf` are of equal lengths.
+ BitVector bv(0, true, Allocator::GetMallocAllocator());
+ uint32_t buf;
+
+ bv.SetBit(0);
+ bv.SetBit(17);
+ bv.SetBit(26);
+ EXPECT_EQ(sizeof(buf), bv.GetSizeOf());
+
+ bv.CopyTo(&buf, sizeof(buf));
+ EXPECT_EQ(0x04020001u, buf);
+ }
+
+ {
+ // Test copying when the `bv.storage_` is longer than `buf`. As long as
+ // `buf` is long enough to hold all set bits, copying should succeed.
+ BitVector bv(0, true, Allocator::GetMallocAllocator());
+ uint8_t buf[5];
+
+ bv.SetBit(18);
+ bv.SetBit(39);
+ EXPECT_LT(sizeof(buf), bv.GetSizeOf());
+
+ bv.CopyTo(buf, sizeof(buf));
+ EXPECT_EQ(0x00u, buf[0]);
+ EXPECT_EQ(0x00u, buf[1]);
+ EXPECT_EQ(0x04u, buf[2]);
+ EXPECT_EQ(0x00u, buf[3]);
+ EXPECT_EQ(0x80u, buf[4]);
+ }
+
+ {
+ // Test zero padding when `bv.storage_` is shorter than `buf`.
+ BitVector bv(0, true, Allocator::GetMallocAllocator());
+ uint32_t buf[2];
+
+ bv.SetBit(18);
+ bv.SetBit(31);
+ EXPECT_GT(sizeof(buf), bv.GetSizeOf());
+
+ bv.CopyTo(buf, sizeof(buf));
+ EXPECT_EQ(0x80040000U, buf[0]);
+ EXPECT_EQ(0x00000000U, buf[1]);
+ }
+}
+
} // namespace art
diff --git a/runtime/stack_map.h b/runtime/stack_map.h
index eefdaa7..ba0b6d6 100644
--- a/runtime/stack_map.h
+++ b/runtime/stack_map.h
@@ -671,9 +671,7 @@
void SetStackMask(const CodeInfo& info, const BitVector& sp_map) {
MemoryRegion region = GetStackMask(info);
- for (size_t i = 0; i < region.size_in_bits(); i++) {
- region.StoreBit(i, sp_map.IsBitSet(i));
- }
+ sp_map.CopyTo(region.start(), region.size());
}
bool HasDexRegisterMap(const CodeInfo& info) const {
