Alexander Markov
ddfc98337b
This is a reland of b6dc4dad4d
TEST=ci
Original change's description:
> [vm/aot] Avoid using most Code objects in stack traces with --dwarf-stack-traces
>
> The following changes are done in preparation for the removal of Code
> objects in AOT with --dwarf-stack-traces:
>
> * Stack trace objects are extended to hold uword PCs (which may not
> fit into Smi range).
>
> * Scanning stack frames in GC (StackFrame::VisitObjectPointers)
> now avoids using Code objects.
> In order to find CompressedStackMaps it now calls
> ReversePc::FindCompressedStackMaps.
>
> * Singleton Code object (StubCode::UnknownDartCode()) is prepared as
> a replacement for Code objects in stack traces. It has
> PayloadStart() == 0 and Size() == kUwordMax so it includes
> arbitrary PCs.
>
> * In --dwarf-stack-traces mode, most Code objects obtained from stack
> frames are replaced with StubCode::UnknownDartCode().
> This simulates future behavior of ReversePc::Lookup when Code objects
> will be removed.
>
> Issue: https://github.com/dart-lang/sdk/issues/44852
> Change-Id: I7cec7b8b9396c9cfeca3c256a412ba4e82a7e0c4
> TEST=ci
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/182720
> Commit-Queue: Alexander Markov <alexmarkov@google.com>
> Reviewed-by: Tess Strickland <sstrickl@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>
Change-Id: Ia2fc4672a085cd963b7fc103369851df3603590c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/186202
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
102 lines
3.1 KiB
C++
102 lines
3.1 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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#include "vm/reverse_pc_lookup_cache.h"
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#include "vm/isolate.h"
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#include "vm/object.h"
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#include "vm/object_store.h"
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namespace dart {
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CodePtr ReversePc::LookupInGroup(IsolateGroup* group,
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uword pc,
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bool is_return_address) {
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#if defined(DART_PRECOMPILED_RUNTIME)
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// This can run in the middle of GC and must not allocate handles.
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NoSafepointScope no_safepoint;
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if (is_return_address) {
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pc--;
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}
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// This expected number of tables is low, so we go through them linearly. If
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// this changes, would could sort the table list during deserialization and
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// binary search for the table.
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GrowableObjectArrayPtr tables = group->object_store()->code_order_tables();
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intptr_t tables_length = Smi::Value(tables->untag()->length_);
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for (intptr_t i = 0; i < tables_length; i++) {
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ArrayPtr table =
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static_cast<ArrayPtr>(tables->untag()->data_->untag()->data()[i]);
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intptr_t lo = 0;
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intptr_t hi = Smi::Value(table->untag()->length_) - 1;
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// Fast check if pc belongs to this table.
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if (lo > hi) {
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continue;
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}
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CodePtr first = static_cast<CodePtr>(table->untag()->data()[lo]);
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if (pc < Code::PayloadStartOf(first)) {
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continue;
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}
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CodePtr last = static_cast<CodePtr>(table->untag()->data()[hi]);
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if (pc >= (Code::PayloadStartOf(last) + Code::PayloadSizeOf(last))) {
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continue;
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}
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// Binary search within the table for the matching Code.
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while (lo <= hi) {
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intptr_t mid = (hi - lo + 1) / 2 + lo;
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ASSERT(mid >= lo);
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ASSERT(mid <= hi);
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CodePtr code = static_cast<CodePtr>(table->untag()->data()[mid]);
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uword code_start = Code::PayloadStartOf(code);
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uword code_end = code_start + Code::PayloadSizeOf(code);
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if (pc < code_start) {
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hi = mid - 1;
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} else if (pc >= code_end) {
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lo = mid + 1;
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} else {
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return code;
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}
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}
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}
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#endif // defined(DART_PRECOMPILED_RUNTIME)
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return Code::null();
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}
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CodePtr ReversePc::Lookup(IsolateGroup* group,
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uword pc,
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bool is_return_address) {
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ASSERT(FLAG_precompiled_mode && FLAG_use_bare_instructions);
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NoSafepointScope no_safepoint;
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CodePtr code = LookupInGroup(group, pc, is_return_address);
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if (code == Code::null()) {
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code = LookupInGroup(Dart::vm_isolate_group(), pc, is_return_address);
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}
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return code;
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}
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CompressedStackMapsPtr ReversePc::FindCompressedStackMaps(
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IsolateGroup* group,
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uword pc,
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bool is_return_address,
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uword* code_start) {
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ASSERT(FLAG_precompiled_mode && FLAG_use_bare_instructions);
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NoSafepointScope no_safepoint;
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CodePtr code = Lookup(group, pc, is_return_address);
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if (code != Code::null()) {
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*code_start = Code::PayloadStartOf(code);
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return code->untag()->compressed_stackmaps();
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}
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*code_start = 0;
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return CompressedStackMaps::null();
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}
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} // namespace dart
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