1//=-- MemProfSummary.cpp - MemProf summary support ---------------=//
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 contains MemProf summary support.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/ProfileData/MemProfSummary.h"
14
15using namespace llvm;
16using namespace llvm::memprof;
17
18void MemProfSummary::printSummaryYaml(raw_ostream &OS) const {
19 // For now emit as YAML comments, since they aren't read on input.
20 OS << "---\n";
21 OS << "# MemProfSummary:\n";
22 OS << "# Total contexts: " << NumContexts << "\n";
23 OS << "# Total cold contexts: " << NumColdContexts << "\n";
24 OS << "# Total hot contexts: " << NumHotContexts << "\n";
25 OS << "# Maximum cold context total size: " << MaxColdTotalSize << "\n";
26 OS << "# Maximum warm context total size: " << MaxWarmTotalSize << "\n";
27 OS << "# Maximum hot context total size: " << MaxHotTotalSize << "\n";
28}
29
30void MemProfSummary::write(ProfOStream &OS) const {
31 // Write the current number of fields first, which helps enable backwards and
32 // forwards compatibility (see comment in header).
33 OS.write32(V: memprof::MemProfSummary::getNumSummaryFields());
34 auto StartPos = OS.tell();
35 (void)StartPos;
36 OS.write(V: NumContexts);
37 OS.write(V: NumColdContexts);
38 OS.write(V: NumHotContexts);
39 OS.write(V: MaxColdTotalSize);
40 OS.write(V: MaxWarmTotalSize);
41 OS.write(V: MaxHotTotalSize);
42 // Sanity check that the number of fields was kept in sync with actual fields.
43 assert((OS.tell() - StartPos) / 8 == MemProfSummary::getNumSummaryFields());
44}
45
46std::unique_ptr<MemProfSummary>
47MemProfSummary::deserialize(const unsigned char *&Ptr) {
48 auto NumSummaryFields =
49 support::endian::readNext<uint32_t, llvm::endianness::little>(memory&: Ptr);
50 // The initial version of the summary contains 6 fields. To support backwards
51 // compatibility with older profiles, if new summary fields are added (until a
52 // version bump) this code will need to check NumSummaryFields against the
53 // current value of MemProfSummary::getNumSummaryFields(). If NumSummaryFields
54 // is lower then default values will need to be filled in for the newer fields
55 // instead of trying to read them from the profile.
56 //
57 // For now, assert that the profile contains at least as many fields as
58 // expected by the code.
59 assert(NumSummaryFields >= MemProfSummary::getNumSummaryFields());
60
61 auto MemProfSum = std::make_unique<MemProfSummary>(
62 args: support::endian::read<uint64_t, llvm::endianness::little>(P: Ptr),
63 args: support::endian::read<uint64_t, llvm::endianness::little>(P: Ptr + 8),
64 args: support::endian::read<uint64_t, llvm::endianness::little>(P: Ptr + 16),
65 args: support::endian::read<uint64_t, llvm::endianness::little>(P: Ptr + 24),
66 args: support::endian::read<uint64_t, llvm::endianness::little>(P: Ptr + 32),
67 args: support::endian::read<uint64_t, llvm::endianness::little>(P: Ptr + 40));
68
69 // Enable forwards compatibility by skipping past any additional fields in the
70 // profile's summary.
71 Ptr += NumSummaryFields * sizeof(uint64_t);
72
73 return MemProfSum;
74}
75