Martin Kustermann
3669086a40
In AOT we can have unboxed fields that will not be visited by GC
visitors and as such are also not reported as <obj>.references when
producing heap snapshots.
Though the heapsnapshot's <class>.fields will contain entries
for unboxed fields, which causes the fields index calculation to be
incorrect.
This can cause various confusing things, e.g. incorrectly caluclated
retaining paths, since the <class>.fields.index doesn't match the
index in <obj>.references.
To fix this this CL will change the visiting code to emit dummy
references for unboxed fields.
The written test uncovered a few other issues:
- report type_arguments and native_fields in <class>.fields
=> the visitors already visit those fields
- fix `Class::next_{host,target}_field_offset` for classes
with native fields
=> this will also shrink size of `NativeWrapperClass` subclasses
- ensure classes with vm-defined layout are finalized
=> we assume objects should only exist in heap if their class
is finalized
- fix `FfiNativeFunction` type_argument offset
- fixes for object fields list
=> add missing entries, fix existing entries
Fixes https://github.com/dart-lang/sdk/issues/49711
TEST=vm/dart{,_2}/heap_snapshot_regress_49711_test
Change-Id: I8e25680b2c0c8c49caafbb8da57b0b6419e89c4f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/255814
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
// Copyright (c) 2018, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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//
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// This file (and "raw_object_fields.cc") provide a kind of reflection that
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// allows us to identify the name of fields in hand-written "Raw..." classes
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// (from "raw_object.h") given the class and the offset within the object. This
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// is used for example by the snapshot profile writer ("v8_snapshot_writer.h")
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// to show the property names of these built-in objects in the snapshot profile.
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#ifndef RUNTIME_VM_RAW_OBJECT_FIELDS_H_
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#define RUNTIME_VM_RAW_OBJECT_FIELDS_H_
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#include <utility>
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#include "vm/hash_map.h"
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#include "vm/object.h"
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#include "vm/raw_object.h"
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namespace dart {
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#if defined(DART_PRECOMPILER) || !defined(PRODUCT)
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class OffsetsTable : public ZoneAllocated {
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public:
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explicit OffsetsTable(Zone* zone);
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// Returns 'nullptr' if no offset was found.
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// Otherwise, the returned string is allocated in global static memory.
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const char* FieldNameForOffset(intptr_t cid, intptr_t offset);
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struct OffsetsTableEntry {
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intptr_t class_id;
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const char* field_name;
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bool is_compressed_pointer;
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intptr_t offset;
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};
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static const MallocGrowableArray<OffsetsTableEntry>& offsets_table();
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static void Init();
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static void Cleanup();
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private:
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struct IntAndIntToStringMapTraits {
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typedef std::pair<intptr_t, intptr_t> Key;
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typedef const char* Value;
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struct Pair {
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Key key;
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Value value;
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Pair() : key({-1, -1}), value(nullptr) {}
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Pair(Key k, Value v) : key(k), value(v) {}
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};
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static Value ValueOf(Pair pair) { return pair.value; }
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static Key KeyOf(Pair pair) { return pair.key; }
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static uword Hash(Key key) {
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return Utils::WordHash(key.first ^ key.second);
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}
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static bool IsKeyEqual(Pair x, Key y) {
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return x.key.first == y.first && x.key.second == y.second;
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}
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};
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DirectChainedHashMap<IntAndIntToStringMapTraits> cached_offsets_;
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};
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#else
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class OffsetsTable : public ZoneAllocated {
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public:
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explicit OffsetsTable(Zone* zone) {}
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const char* FieldNameForOffset(intptr_t cid, intptr_t offset) {
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return nullptr;
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}
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static void Init() {}
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static void Cleanup() {}
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};
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#endif
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} // namespace dart
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#endif // RUNTIME_VM_RAW_OBJECT_FIELDS_H_
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