1//===-- memprof_shadow_setup.cpp -----------------------------------------===//
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// This file is a part of MemProfiler, a memory profiler.
10//
11// Set up the shadow memory.
12//===----------------------------------------------------------------------===//
13
14#include "sanitizer_common/sanitizer_platform.h"
15
16#include "memprof_internal.h"
17#include "memprof_mapping.h"
18
19namespace __memprof {
20
21static void ProtectGap(uptr addr, uptr size) {
22 if (!flags()->protect_shadow_gap) {
23 // The shadow gap is unprotected, so there is a chance that someone
24 // is actually using this memory. Which means it needs a shadow...
25 uptr GapShadowBeg = RoundDownTo(MEM_TO_SHADOW(addr), boundary: GetPageSizeCached());
26 uptr GapShadowEnd =
27 RoundUpTo(MEM_TO_SHADOW(addr + size), boundary: GetPageSizeCached()) - 1;
28 if (Verbosity())
29 Printf(format: "protect_shadow_gap=0:"
30 " not protecting shadow gap, allocating gap's shadow\n"
31 "|| `[%p, %p]` || ShadowGap's shadow ||\n",
32 GapShadowBeg, GapShadowEnd);
33 ReserveShadowMemoryRange(beg: GapShadowBeg, end: GapShadowEnd,
34 name: "unprotected gap shadow");
35 return;
36 }
37 __sanitizer::ProtectGap(addr, size, kZeroBaseShadowStart,
38 kZeroBaseMaxShadowStart);
39}
40
41void InitializeShadowMemory() {
42 uptr shadow_start = FindDynamicShadowStart();
43 // Update the shadow memory address (potentially) used by instrumentation.
44 __memprof_shadow_memory_dynamic_address = shadow_start;
45
46 if (kLowShadowBeg)
47 shadow_start -= GetMmapGranularity();
48
49 if (Verbosity())
50 PrintAddressSpaceLayout();
51
52 // mmap the low shadow plus at least one page at the left.
53 if (kLowShadowBeg)
54 ReserveShadowMemoryRange(beg: shadow_start, kLowShadowEnd, name: "low shadow");
55 // mmap the high shadow.
56 ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd, name: "high shadow");
57 // protect the gap.
58 ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
59 CHECK_EQ(kShadowGapEnd, kHighShadowBeg - 1);
60}
61
62} // namespace __memprof
63

source code of compiler-rt/lib/memprof/memprof_shadow_setup.cpp