96b7c64b8a
Recently in #107731 this change was revereted due to excess memory size in `TestSkinnyCore`. This was due to a bug where a range's end was being passed as size. Creating massive memory ranges. Additionally, and requiring additional review, I added more unit tests and more verbose logic to the merging of save core memory regions. @jasonmolenda as an FYI.
87 lines
3.5 KiB
C++
87 lines
3.5 KiB
C++
//===-- CoreFileMemoryRanges.cpp --------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "lldb/Target/CoreFileMemoryRanges.h"
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using namespace lldb;
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using namespace lldb_private;
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using Entry = CoreFileMemoryRanges::Entry;
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static bool Overlaps(const Entry *region_one, const Entry *region_two) {
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return !(region_one->GetRangeEnd() < region_two->GetRangeBase() ||
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region_two->GetRangeEnd() < region_one->GetRangeBase());
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}
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static bool IntersectHelper(const Entry *region_one, const Entry *region_two) {
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return region_one->GetRangeBase() == region_two->GetRangeEnd() ||
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region_one->GetRangeEnd() == region_two->GetRangeBase();
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}
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static bool OnlyIntersects(const Entry *region_one, const Entry *region_two) {
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return IntersectHelper(region_one, region_two) ||
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IntersectHelper(region_two, region_one);
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}
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static bool PermissionsMatch(const Entry *region_one, const Entry *region_two) {
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return region_one->data.lldb_permissions == region_two->data.lldb_permissions;
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}
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// This assumes any overlapping ranges will share the same permissions
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// and that adjacent ranges could have different permissions.
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Status CoreFileMemoryRanges::FinalizeCoreFileSaveRanges() {
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Status error;
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this->Sort();
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for (size_t i = this->GetSize() - 1; i > 0; i--) {
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auto region_one = this->GetMutableEntryAtIndex(i);
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auto region_two = this->GetMutableEntryAtIndex(i - 1);
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if (Overlaps(region_one, region_two)) {
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// It's okay for interesecting regions to have different permissions but
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// if they overlap we fail because we don't know what to do with them.
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if (!PermissionsMatch(region_one, region_two)) {
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// Permissions mismatch and it's not a simple intersection.
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if (!OnlyIntersects(region_one, region_two)) {
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error = Status::FromErrorStringWithFormatv(
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"Memory region at {0}::{1} has different permssions than "
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"overlapping region at {2}::{3}",
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region_one->GetRangeBase(), region_one->GetRangeEnd(),
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region_two->GetRangeBase(), region_two->GetRangeEnd());
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return error;
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}
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// Simple intersection, we can just not merge these.
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else
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continue;
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}
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const addr_t base =
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std::min(region_one->GetRangeBase(), region_two->GetRangeBase());
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const addr_t byte_size =
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std::max(region_one->GetRangeEnd(), region_two->GetRangeEnd()) - base;
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region_two->SetRangeBase(base);
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region_two->SetByteSize(byte_size);
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// Because this is a range data vector, the entry has a base as well
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// as the data contained in the entry. So we have to update both.
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// And llvm::AddressRange isn't mutable so we have to create a new one.
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llvm::AddressRange range(base, base + byte_size);
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const CoreFileMemoryRange core_range = {
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range, region_two->data.lldb_permissions};
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region_two->data = core_range;
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// Erase is delete from [Inclusive, exclusive index).
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if (!this->Erase(i, i + 1)) {
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error = Status::FromErrorStringWithFormat(
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"Core file memory ranges mutated outside of "
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"CalculateCoreFileSaveRanges");
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return error;
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}
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}
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}
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return error;
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}
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