1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
//===- LTO.cpp ------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "LTO.h"
#include "Config.h"
#include "Driver.h"
#include "InputFiles.h"
#include "Symbols.h"
#include "Target.h"
#include "lld/Common/Args.h"
#include "lld/Common/CommonLinkerContext.h"
#include "lld/Common/Strings.h"
#include "lld/Common/TargetOptionsCommandFlags.h"
#include "llvm/LTO/Config.h"
#include "llvm/LTO/LTO.h"
#include "llvm/Support/Caching.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/ObjCARC.h"
using namespace lld;
using namespace lld::macho;
using namespace llvm;
using namespace llvm::MachO;
using namespace llvm::sys;
static lto::Config createConfig() {
lto::Config c;
c.Options = initTargetOptionsFromCodeGenFlags();
c.CodeModel = getCodeModelFromCMModel();
c.CPU = getCPUStr();
c.MAttrs = getMAttrs();
c.DiagHandler = diagnosticHandler;
c.UseNewPM = config->ltoNewPassManager;
c.PreCodeGenPassesHook = [](legacy::PassManager &pm) {
pm.add(createObjCARCContractPass());
};
c.TimeTraceEnabled = config->timeTraceEnabled;
c.TimeTraceGranularity = config->timeTraceGranularity;
c.OptLevel = config->ltoo;
c.CGOptLevel = args::getCGOptLevel(config->ltoo);
if (config->saveTemps)
checkError(c.addSaveTemps(config->outputFile.str() + ".",
/*UseInputModulePath=*/true));
return c;
}
BitcodeCompiler::BitcodeCompiler() {
lto::ThinBackend backend = lto::createInProcessThinBackend(
heavyweight_hardware_concurrency(config->thinLTOJobs));
ltoObj = std::make_unique<lto::LTO>(createConfig(), backend);
}
void BitcodeCompiler::add(BitcodeFile &f) {
ArrayRef<lto::InputFile::Symbol> objSyms = f.obj->symbols();
std::vector<lto::SymbolResolution> resols;
resols.reserve(objSyms.size());
// Provide a resolution to the LTO API for each symbol.
bool exportDynamic =
config->outputType != MH_EXECUTE || config->exportDynamic;
auto symIt = f.symbols.begin();
for (const lto::InputFile::Symbol &objSym : objSyms) {
resols.emplace_back();
lto::SymbolResolution &r = resols.back();
Symbol *sym = *symIt++;
// Ideally we shouldn't check for SF_Undefined but currently IRObjectFile
// reports two symbols for module ASM defined. Without this check, lld
// flags an undefined in IR with a definition in ASM as prevailing.
// Once IRObjectFile is fixed to report only one symbol this hack can
// be removed.
r.Prevailing = !objSym.isUndefined() && sym->getFile() == &f;
if (const auto *defined = dyn_cast<Defined>(sym))
r.ExportDynamic =
defined->isExternal() && !defined->privateExtern && exportDynamic;
else if (const auto *common = dyn_cast<CommonSymbol>(sym))
r.ExportDynamic = !common->privateExtern && exportDynamic;
r.VisibleToRegularObj =
sym->isUsedInRegularObj || (r.Prevailing && r.ExportDynamic);
// Un-define the symbol so that we don't get duplicate symbol errors when we
// load the ObjFile emitted by LTO compilation.
if (r.Prevailing)
replaceSymbol<Undefined>(sym, sym->getName(), sym->getFile(),
RefState::Strong);
// TODO: set the other resolution configs properly
}
checkError(ltoObj->add(std::move(f.obj), resols));
}
// Merge all the bitcode files we have seen, codegen the result
// and return the resulting ObjectFile(s).
std::vector<ObjFile *> BitcodeCompiler::compile() {
unsigned maxTasks = ltoObj->getMaxTasks();
buf.resize(maxTasks);
files.resize(maxTasks);
// The -cache_path_lto option specifies the path to a directory in which
// to cache native object files for ThinLTO incremental builds. If a path was
// specified, configure LTO to use it as the cache directory.
FileCache cache;
if (!config->thinLTOCacheDir.empty())
cache =
check(localCache("ThinLTO", "Thin", config->thinLTOCacheDir,
[&](size_t task, std::unique_ptr<MemoryBuffer> mb) {
files[task] = std::move(mb);
}));
checkError(ltoObj->run(
[&](size_t task) {
return std::make_unique<CachedFileStream>(
std::make_unique<raw_svector_ostream>(buf[task]));
},
cache));
if (!config->thinLTOCacheDir.empty())
pruneCache(config->thinLTOCacheDir, config->thinLTOCachePolicy);
if (config->saveTemps) {
if (!buf[0].empty())
saveBuffer(buf[0], config->outputFile + ".lto.o");
for (unsigned i = 1; i != maxTasks; ++i)
saveBuffer(buf[i], config->outputFile + Twine(i) + ".lto.o");
}
if (!config->ltoObjPath.empty())
fs::create_directories(config->ltoObjPath);
std::vector<ObjFile *> ret;
for (unsigned i = 0; i != maxTasks; ++i) {
if (buf[i].empty())
continue;
SmallString<261> filePath("/tmp/lto.tmp");
uint32_t modTime = 0;
if (!config->ltoObjPath.empty()) {
filePath = config->ltoObjPath;
path::append(filePath, Twine(i) + "." +
getArchitectureName(config->arch()) +
".lto.o");
saveBuffer(buf[i], filePath);
modTime = getModTime(filePath);
}
ret.push_back(make<ObjFile>(
MemoryBufferRef(buf[i], saver().save(filePath.str())), modTime, ""));
}
for (std::unique_ptr<MemoryBuffer> &file : files)
if (file)
ret.push_back(make<ObjFile>(*file, 0, ""));
return ret;
}
|
