1//===-- CoreFileMemoryRanges.cpp --------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "lldb/Target/CoreFileMemoryRanges.h"
10
11using namespace lldb;
12using namespace lldb_private;
13
14using Entry = CoreFileMemoryRanges::Entry;
15
16static bool Overlaps(const Entry *region_one, const Entry *region_two) {
17 return !(region_one->GetRangeEnd() < region_two->GetRangeBase() ||
18 region_two->GetRangeEnd() < region_one->GetRangeBase());
19}
20
21static bool IntersectHelper(const Entry *region_one, const Entry *region_two) {
22 return region_one->GetRangeBase() == region_two->GetRangeEnd() ||
23 region_one->GetRangeEnd() == region_two->GetRangeBase();
24}
25
26static bool OnlyIntersects(const Entry *region_one, const Entry *region_two) {
27 return IntersectHelper(region_one, region_two) ||
28 IntersectHelper(region_one: region_two, region_two: region_one);
29}
30
31static bool PermissionsMatch(const Entry *region_one, const Entry *region_two) {
32 return region_one->data.lldb_permissions == region_two->data.lldb_permissions;
33}
34
35// This assumes any overlapping ranges will share the same permissions
36// and that adjacent ranges could have different permissions.
37Status CoreFileMemoryRanges::FinalizeCoreFileSaveRanges() {
38 Status error;
39 this->Sort();
40 for (size_t i = this->GetSize() - 1; i > 0; i--) {
41 auto region_one = this->GetMutableEntryAtIndex(i);
42 auto region_two = this->GetMutableEntryAtIndex(i: i - 1);
43 if (Overlaps(region_one, region_two)) {
44 // It's okay for interesecting regions to have different permissions but
45 // if they overlap we fail because we don't know what to do with them.
46 if (!PermissionsMatch(region_one, region_two)) {
47 // Permissions mismatch and it's not a simple intersection.
48 if (!OnlyIntersects(region_one, region_two)) {
49 error = Status::FromErrorStringWithFormatv(
50 format: "Memory region at {0}::{1} has different permssions than "
51 "overlapping region at {2}::{3}",
52 args: region_one->GetRangeBase(), args: region_one->GetRangeEnd(),
53 args: region_two->GetRangeBase(), args: region_two->GetRangeEnd());
54 return error;
55 }
56 // Simple intersection, we can just not merge these.
57 else
58 continue;
59 }
60 const addr_t base =
61 std::min(a: region_one->GetRangeBase(), b: region_two->GetRangeBase());
62 const addr_t byte_size =
63 std::max(a: region_one->GetRangeEnd(), b: region_two->GetRangeEnd()) - base;
64
65 region_two->SetRangeBase(base);
66 region_two->SetByteSize(byte_size);
67
68 // Because this is a range data vector, the entry has a base as well
69 // as the data contained in the entry. So we have to update both.
70 // And llvm::AddressRange isn't mutable so we have to create a new one.
71 llvm::AddressRange range(base, base + byte_size);
72 const CoreFileMemoryRange core_range = {
73 .range: range, .lldb_permissions: region_two->data.lldb_permissions};
74 region_two->data = core_range;
75 // Erase is delete from [Inclusive, exclusive index).
76 if (!this->Erase(start: i, end: i + 1)) {
77 error = Status::FromErrorStringWithFormat(
78 format: "Core file memory ranges mutated outside of "
79 "CalculateCoreFileSaveRanges");
80 return error;
81 }
82 }
83 }
84
85 return error;
86}
87

source code of lldb/source/Target/CoreFileMemoryRanges.cpp