Tess Strickland
45a46ca2b8
Unlikecfc8e6de, this does _not_ replace the default variable length encoding for {Read,Write}Streams, but insteads adds separate {Read,Write}{S,}LEB128 methods to the appropriate classes. If we later find the cause of the issues that led to the revert ofcfc8e6de, it'll be easy to switch over then. Note that WriteLEB128 asserts that the value is non-negative if used with a signed type (since negative values suggests that SLEB128 should be used instead for minimal encoding). Also removes the various other encoding and decoding methods for (S)LEB128 across the codebase and changes those clients to use {Read,Write}Streams instead. Other cleanups: * Various constant-related cleanups in datastream.h. * Adds DART_FORCE_INLINE to ReadStream::ReadByte and uses it in the default variable length decoding methods for retrieving bytes from the stream instead of managing current_ by hand. * Creates a canonical empty CompressedStackMaps instance and uses that instead of the null CompressedStackMaps instance in most cases. The only remaining (expected) use of the null CompressedStackMaps instance is for the global table in the object store when no global table exists (e.g., in JIT mode before any snapshotting). * Moves CompressedStackMapsIterator from code_descriptors.h to an Iterator class within CompressedStackMaps in object.h (similar to PcDescriptors::Iterator), to limit friend declarations and because it conceptually makes more sense as part of CompressedStackMaps. * Removed CompressedStackMaps::PayloadByte, since existing clients (CompressedStackMaps::Iterator, StackMapEntry in program_visitor.cc) are better served by just operating on the payload buffer directly (with appropriate NoSafepointScopes). * WriteStreams no longer allocate their initial space on construction, but rather on the first write, so no allocation is performed by constructing a never-used WriteStream. Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-debug-simarm_x64-try,vm-kernel-precomp-mac-release-simarm64-try,vm-kernel-mac-debug-x64-try,vm-kernel-win-debug-x64-try,vm-kernel-win-debug-ia32-try,vm-kernel-precomp-win-release-x64-try,vm-kernel-ubsan-linux-release-x64-try,vm-kernel-tsan-linux-release-x64-try,vm-kernel-precomp-ubsan-linux-release-x64-try,vm-kernel-precomp-tsan-linux-release-x64-try,vm-kernel-precomp-msan-linux-release-x64-try,vm-kernel-precomp-asan-linux-release-x64-try,vm-kernel-msan-linux-release-x64-try,vm-kernel-asan-linux-release-x64-try Change-Id: Ice63321abaa79157fbe9f230a864c8bba0e6dea9 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/166421 Reviewed-by: Ryan Macnak <rmacnak@google.com> Commit-Queue: Tess Strickland <sstrickl@google.com>
80 lines
2.3 KiB
C++
80 lines
2.3 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
|
// BSD-style license that can be found in the LICENSE file.
|
|
|
|
#ifndef RUNTIME_VM_BITMAP_H_
|
|
#define RUNTIME_VM_BITMAP_H_
|
|
|
|
#include "vm/allocation.h"
|
|
#include "vm/datastream.h"
|
|
#include "vm/thread_state.h"
|
|
#include "vm/zone.h"
|
|
|
|
namespace dart {
|
|
|
|
// BitmapBuilder is used to build a bitmap. The implementation is optimized
|
|
// for a dense set of small bit maps without a fixed upper bound (e.g: a
|
|
// pointer map description of a stack).
|
|
class BitmapBuilder : public ZoneAllocated {
|
|
public:
|
|
BitmapBuilder()
|
|
: length_(0),
|
|
data_size_in_bytes_(kInitialSizeInBytes),
|
|
data_(ThreadState::Current()->zone()->Alloc<uint8_t>(
|
|
kInitialSizeInBytes)) {
|
|
memset(data_, 0, kInitialSizeInBytes);
|
|
}
|
|
|
|
intptr_t Length() const { return length_; }
|
|
void SetLength(intptr_t length);
|
|
|
|
// Get/Set individual bits in the bitmap, setting bits beyond the bitmap's
|
|
// length increases the length and expands the underlying bitmap if
|
|
// needed.
|
|
bool Get(intptr_t bit_offset) const;
|
|
void Set(intptr_t bit_offset, bool value);
|
|
|
|
// Return the bit offset of the highest bit set.
|
|
intptr_t Maximum() const;
|
|
|
|
// Return the bit offset of the lowest bit set.
|
|
intptr_t Minimum() const;
|
|
|
|
// Sets min..max (inclusive) to value.
|
|
void SetRange(intptr_t min, intptr_t max, bool value);
|
|
|
|
void Print() const;
|
|
void AppendAsBytesTo(BaseWriteStream* stream) const;
|
|
|
|
private:
|
|
static const intptr_t kInitialSizeInBytes = 16;
|
|
static const intptr_t kIncrementSizeInBytes = 16;
|
|
|
|
bool InRange(intptr_t offset) const {
|
|
if (offset < 0) {
|
|
FATAL1(
|
|
"Fatal error in BitmapBuilder::InRange :"
|
|
" invalid bit_offset, %" Pd "\n",
|
|
offset);
|
|
}
|
|
return (offset < length_);
|
|
}
|
|
|
|
// Get/Set a bit that is known to be covered by the backing store.
|
|
bool GetBit(intptr_t bit_offset) const;
|
|
void SetBit(intptr_t bit_offset, bool value);
|
|
|
|
intptr_t length_;
|
|
|
|
// Backing store for the bitmap. Reading bits beyond the backing store
|
|
// (up to length_) is allowed and they are assumed to be false.
|
|
intptr_t data_size_in_bytes_;
|
|
uint8_t* data_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(BitmapBuilder);
|
|
};
|
|
|
|
} // namespace dart
|
|
|
|
#endif // RUNTIME_VM_BITMAP_H_
|