1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4  * License, v. 2.0. If a copy of the MPL was not distributed with this
5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 
7 #include "mozilla/MemoryInfo.h"
8 
9 #include "mozilla/DebugOnly.h"
10 
11 #include <algorithm>
12 #include <windows.h>
13 
14 namespace mozilla {
15 
16 /* static */
Get(const void * aPtr,size_t aSize)17 MemoryInfo MemoryInfo::Get(const void* aPtr, size_t aSize) {
18   MemoryInfo result;
19 
20   result.mStart = uintptr_t(aPtr);
21   const char* ptr = reinterpret_cast<const char*>(aPtr);
22   const char* end = ptr + aSize;
23   DebugOnly<void*> base = nullptr;
24   while (ptr < end) {
25     MEMORY_BASIC_INFORMATION basicInfo;
26     if (!VirtualQuery(ptr, &basicInfo, sizeof(basicInfo))) {
27       break;
28     }
29 
30     MOZ_ASSERT_IF(base, base == basicInfo.AllocationBase);
31     base = basicInfo.AllocationBase;
32 
33     size_t regionSize =
34         std::min(size_t(basicInfo.RegionSize), size_t(end - ptr));
35 
36     if (basicInfo.State == MEM_COMMIT) {
37       result.mCommitted += regionSize;
38     } else if (basicInfo.State == MEM_RESERVE) {
39       result.mReserved += regionSize;
40     } else if (basicInfo.State == MEM_FREE) {
41       result.mFree += regionSize;
42     } else {
43       MOZ_ASSERT_UNREACHABLE("Unexpected region state");
44     }
45     result.mSize += regionSize;
46     ptr += regionSize;
47 
48     if (result.mType.isEmpty()) {
49       if (basicInfo.Type & MEM_IMAGE) {
50         result.mType += PageType::Image;
51       }
52       if (basicInfo.Type & MEM_MAPPED) {
53         result.mType += PageType::Mapped;
54       }
55       if (basicInfo.Type & MEM_PRIVATE) {
56         result.mType += PageType::Private;
57       }
58 
59       // The first 8 bits of AllocationProtect are an enum. The remaining bits
60       // are flags.
61       switch (basicInfo.AllocationProtect & 0xff) {
62         case PAGE_EXECUTE_WRITECOPY:
63           result.mPerms += Perm::CopyOnWrite;
64           [[fallthrough]];
65         case PAGE_EXECUTE_READWRITE:
66           result.mPerms += Perm::Write;
67           [[fallthrough]];
68         case PAGE_EXECUTE_READ:
69           result.mPerms += Perm::Read;
70           [[fallthrough]];
71         case PAGE_EXECUTE:
72           result.mPerms += Perm::Execute;
73           break;
74 
75         case PAGE_WRITECOPY:
76           result.mPerms += Perm::CopyOnWrite;
77           [[fallthrough]];
78         case PAGE_READWRITE:
79           result.mPerms += Perm::Write;
80           [[fallthrough]];
81         case PAGE_READONLY:
82           result.mPerms += Perm::Read;
83           break;
84 
85         default:
86           break;
87       }
88 
89       if (basicInfo.AllocationProtect & PAGE_GUARD) {
90         result.mPerms += Perm::Guard;
91       }
92       if (basicInfo.AllocationProtect & PAGE_NOCACHE) {
93         result.mPerms += Perm::NoCache;
94       }
95       if (basicInfo.AllocationProtect & PAGE_WRITECOMBINE) {
96         result.mPerms += Perm::WriteCombine;
97       }
98     }
99   }
100 
101   result.mEnd = uintptr_t(ptr);
102   return result;
103 }
104 
105 }  // namespace mozilla
106