1 /*===- InstrProfilingMerge.c - Profile in-process Merging  ---------------===*\
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 |* This file defines the API needed for in-process merging of profile data
9 |* stored in memory buffer.
10 \*===---------------------------------------------------------------------===*/
11 
12 #include "InstrProfiling.h"
13 #include "InstrProfilingInternal.h"
14 #include "InstrProfilingUtil.h"
15 
16 #define INSTR_PROF_VALUE_PROF_DATA
17 #include "profile/InstrProfData.inc"
18 
19 COMPILER_RT_VISIBILITY
20 void (*VPMergeHook)(ValueProfData *, __llvm_profile_data *);
21 
22 COMPILER_RT_VISIBILITY
23 uint64_t lprofGetLoadModuleSignature() {
24   /* A very fast way to compute a module signature.  */
25   uint64_t Version = __llvm_profile_get_version();
26   uint64_t CounterSize = (uint64_t)(__llvm_profile_end_counters() -
27                                     __llvm_profile_begin_counters());
28   uint64_t DataSize = __llvm_profile_get_data_size(__llvm_profile_begin_data(),
29                                                    __llvm_profile_end_data());
30   uint64_t NamesSize =
31       (uint64_t)(__llvm_profile_end_names() - __llvm_profile_begin_names());
32   uint64_t NumVnodes =
33       (uint64_t)(__llvm_profile_end_vnodes() - __llvm_profile_begin_vnodes());
34   const __llvm_profile_data *FirstD = __llvm_profile_begin_data();
35 
36   return (NamesSize << 40) + (CounterSize << 30) + (DataSize << 20) +
37          (NumVnodes << 10) + (DataSize > 0 ? FirstD->NameRef : 0) + Version +
38          __llvm_profile_get_magic();
39 }
40 
41 /* Returns 1 if profile is not structurally compatible.  */
42 COMPILER_RT_VISIBILITY
43 int __llvm_profile_check_compatibility(const char *ProfileData,
44                                        uint64_t ProfileSize) {
45   /* Check profile header only for now  */
46   __llvm_profile_header *Header = (__llvm_profile_header *)ProfileData;
47   __llvm_profile_data *SrcDataStart, *SrcDataEnd, *SrcData, *DstData;
48   SrcDataStart =
49       (__llvm_profile_data *)(ProfileData + sizeof(__llvm_profile_header) +
50                               Header->BinaryIdsSize);
51   SrcDataEnd = SrcDataStart + Header->DataSize;
52 
53   if (ProfileSize < sizeof(__llvm_profile_header))
54     return 1;
55 
56   /* Check the header first.  */
57   if (Header->Magic != __llvm_profile_get_magic() ||
58       Header->Version != __llvm_profile_get_version() ||
59       Header->DataSize !=
60           __llvm_profile_get_data_size(__llvm_profile_begin_data(),
61                                        __llvm_profile_end_data()) ||
62       Header->CountersSize != (uint64_t)(__llvm_profile_end_counters() -
63                                          __llvm_profile_begin_counters()) ||
64       Header->NamesSize != (uint64_t)(__llvm_profile_end_names() -
65                                       __llvm_profile_begin_names()) ||
66       Header->ValueKindLast != IPVK_Last)
67     return 1;
68 
69   if (ProfileSize < sizeof(__llvm_profile_header) + Header->BinaryIdsSize +
70                         Header->DataSize * sizeof(__llvm_profile_data) +
71                         Header->NamesSize + Header->CountersSize)
72     return 1;
73 
74   for (SrcData = SrcDataStart,
75        DstData = (__llvm_profile_data *)__llvm_profile_begin_data();
76        SrcData < SrcDataEnd; ++SrcData, ++DstData) {
77     if (SrcData->NameRef != DstData->NameRef ||
78         SrcData->FuncHash != DstData->FuncHash ||
79         SrcData->NumCounters != DstData->NumCounters)
80       return 1;
81   }
82 
83   /* Matched! */
84   return 0;
85 }
86 
87 static uintptr_t signextIfWin64(void *V) {
88 #ifdef _WIN64
89   return (uintptr_t)(int32_t)(uintptr_t)V;
90 #else
91   return (uintptr_t)V;
92 #endif
93 }
94 
95 COMPILER_RT_VISIBILITY
96 int __llvm_profile_merge_from_buffer(const char *ProfileData,
97                                      uint64_t ProfileSize) {
98   __llvm_profile_data *SrcDataStart, *SrcDataEnd, *SrcData, *DstData;
99   __llvm_profile_header *Header = (__llvm_profile_header *)ProfileData;
100   uint64_t *SrcCountersStart;
101   const char *SrcNameStart;
102   const char *SrcValueProfDataStart, *SrcValueProfData;
103   uintptr_t CountersDelta = Header->CountersDelta;
104 
105   SrcDataStart =
106       (__llvm_profile_data *)(ProfileData + sizeof(__llvm_profile_header) +
107                               Header->BinaryIdsSize);
108   SrcDataEnd = SrcDataStart + Header->DataSize;
109   SrcCountersStart = (uint64_t *)SrcDataEnd;
110   SrcNameStart = (const char *)(SrcCountersStart + Header->CountersSize);
111   SrcValueProfDataStart =
112       SrcNameStart + Header->NamesSize +
113       __llvm_profile_get_num_padding_bytes(Header->NamesSize);
114   if (SrcNameStart < (const char *)SrcCountersStart)
115     return 1;
116 
117   for (SrcData = SrcDataStart,
118       DstData = (__llvm_profile_data *)__llvm_profile_begin_data(),
119       SrcValueProfData = SrcValueProfDataStart;
120        SrcData < SrcDataEnd; ++SrcData, ++DstData) {
121     // For the in-memory destination, CounterPtr is the distance from the start
122     // address of the data to the start address of the counter. On WIN64,
123     // CounterPtr is a truncated 32-bit value due to COFF limitation. Sign
124     // extend CounterPtr to get the original value.
125     uint64_t *DstCounters =
126         (uint64_t *)((uintptr_t)DstData + signextIfWin64(DstData->CounterPtr));
127     unsigned NVK = 0;
128 
129     // SrcData is a serialized representation of the memory image. We need to
130     // compute the in-buffer counter offset from the in-memory address distance.
131     // The initial CountersDelta is the in-memory address difference
132     // start(__llvm_prf_cnts)-start(__llvm_prf_data), so SrcData->CounterPtr -
133     // CountersDelta computes the offset into the in-buffer counter section.
134     //
135     // On WIN64, CountersDelta is truncated as well, so no need for signext.
136     uint64_t *SrcCounters =
137         SrcCountersStart +
138         ((uintptr_t)SrcData->CounterPtr - CountersDelta) / sizeof(uint64_t);
139     // CountersDelta needs to be decreased as we advance to the next data
140     // record.
141     CountersDelta -= sizeof(*SrcData);
142     unsigned NC = SrcData->NumCounters;
143     if (NC == 0)
144       return 1;
145     if (SrcCounters < SrcCountersStart ||
146         (const char *)SrcCounters >= SrcNameStart ||
147         (const char *)(SrcCounters + NC) > SrcNameStart)
148       return 1;
149     for (unsigned I = 0; I < NC; I++)
150       DstCounters[I] += SrcCounters[I];
151 
152     /* Now merge value profile data. */
153     if (!VPMergeHook)
154       continue;
155 
156     for (unsigned I = 0; I <= IPVK_Last; I++)
157       NVK += (SrcData->NumValueSites[I] != 0);
158 
159     if (!NVK)
160       continue;
161 
162     if (SrcValueProfData >= ProfileData + ProfileSize)
163       return 1;
164     VPMergeHook((ValueProfData *)SrcValueProfData, DstData);
165     SrcValueProfData =
166         SrcValueProfData + ((ValueProfData *)SrcValueProfData)->TotalSize;
167   }
168 
169   return 0;
170 }
171