Repository navigation
Expand file tree
/
Copy pathlto.cpp
More file actions
529 lines (444 loc) · 16.6 KB
/
Copy pathlto.cpp
File metadata and controls
529 lines (444 loc) · 16.6 KB
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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
//===-lto.cpp - LLVM Link Time Optimizer ----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Link Time Optimization library. This library is
// intended to be used by linker to optimize code at link time.
//
//===----------------------------------------------------------------------===//
#include "llvm/Module.h"
#include "llvm/PassManager.h"
#include "llvm/Linker.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/ModuleProvider.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileUtilities.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/System/Program.h"
#include "llvm/System/Signals.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/CodeGen/FileWriters.h"
#include "llvm/Target/SubtargetFeature.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetMachineRegistry.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Analysis/LoadValueNumbering.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/LinkTimeOptimizer.h"
#include <fstream>
#include <ostream>
using namespace llvm;
extern "C"
llvm::LinkTimeOptimizer *createLLVMOptimizer(unsigned VERSION)
{
// Linker records LLVM_LTO_VERSION based on llvm optimizer available
// during linker build. Match linker's recorded LTO VERSION number
// with installed llvm optimizer version. If these numbers do not match
// then linker may not be able to use llvm optimizer dynamically.
if (VERSION != LLVM_LTO_VERSION)
return NULL;
llvm::LTO *l = new llvm::LTO();
return l;
}
/// If symbol is not used then make it internal and let optimizer takes
/// care of it.
void LLVMSymbol::mayBeNotUsed() {
gv->setLinkage(GlobalValue::InternalLinkage);
}
// Map LLVM LinkageType to LTO LinakgeType
static LTOLinkageTypes
getLTOLinkageType(GlobalValue *v)
{
LTOLinkageTypes lt;
if (v->hasExternalLinkage())
lt = LTOExternalLinkage;
else if (v->hasLinkOnceLinkage())
lt = LTOLinkOnceLinkage;
else if (v->hasWeakLinkage())
lt = LTOWeakLinkage;
else
// Otherwise it is internal linkage for link time optimizer
lt = LTOInternalLinkage;
return lt;
}
// MAP LLVM VisibilityType to LTO VisibilityType
static LTOVisibilityTypes
getLTOVisibilityType(GlobalValue *v)
{
LTOVisibilityTypes vis;
if (v->hasHiddenVisibility())
vis = LTOHiddenVisibility;
else if (v->hasProtectedVisibility())
vis = LTOProtectedVisibility;
else
vis = LTODefaultVisibility;
return vis;
}
// Find exeternal symbols referenced by VALUE. This is a recursive function.
static void
findExternalRefs(Value *value, std::set<std::string> &references,
Mangler &mangler) {
if (GlobalValue *gv = dyn_cast<GlobalValue>(value)) {
LTOLinkageTypes lt = getLTOLinkageType(gv);
if (lt != LTOInternalLinkage && strncmp (gv->getName().c_str(), "llvm.", 5))
references.insert(mangler.getValueName(gv));
}
// GlobalValue, even with InternalLinkage type, may have operands with
// ExternalLinkage type. Do not ignore these operands.
if (Constant *c = dyn_cast<Constant>(value))
// Handle ConstantExpr, ConstantStruct, ConstantArry etc..
for (unsigned i = 0, e = c->getNumOperands(); i != e; ++i)
findExternalRefs(c->getOperand(i), references, mangler);
}
/// If Module with InputFilename is available then remove it from allModules
/// and call delete on it.
void
LTO::removeModule (const std::string &InputFilename)
{
NameToModuleMap::iterator pos = allModules.find(InputFilename.c_str());
if (pos == allModules.end())
return;
Module *m = pos->second;
allModules.erase(pos);
delete m;
}
/// InputFilename is a LLVM bitcode file. If Module with InputFilename is
/// available then return it. Otherwise parseInputFilename.
Module *
LTO::getModule(const std::string &InputFilename)
{
Module *m = NULL;
NameToModuleMap::iterator pos = allModules.find(InputFilename.c_str());
if (pos != allModules.end())
m = allModules[InputFilename.c_str()];
else {
if (MemoryBuffer *Buffer
= MemoryBuffer::getFile(&InputFilename[0], InputFilename.size())) {
m = ParseBitcodeFile(Buffer);
delete Buffer;
}
allModules[InputFilename.c_str()] = m;
}
return m;
}
/// InputFilename is a LLVM bitcode file. Reade this bitcode file and
/// set corresponding target triplet string.
void
LTO::getTargetTriple(const std::string &InputFilename,
std::string &targetTriple)
{
Module *m = getModule(InputFilename);
if (m)
targetTriple = m->getTargetTriple();
}
/// InputFilename is a LLVM bitcode file. Read it using bitcode reader.
/// Collect global functions and symbol names in symbols vector.
/// Collect external references in references vector.
/// Return LTO_READ_SUCCESS if there is no error.
enum LTOStatus
LTO::readLLVMObjectFile(const std::string &InputFilename,
NameToSymbolMap &symbols,
std::set<std::string> &references)
{
Module *m = getModule(InputFilename);
if (!m)
return LTO_READ_FAILURE;
// Collect Target info
getTarget(m);
if (!Target)
return LTO_READ_FAILURE;
// Use mangler to add GlobalPrefix to names to match linker names.
// FIXME : Instead of hard coding "-" use GlobalPrefix.
Mangler mangler(*m, Target->getTargetAsmInfo()->getGlobalPrefix());
modules.push_back(m);
for (Module::iterator f = m->begin(), e = m->end(); f != e; ++f) {
LTOLinkageTypes lt = getLTOLinkageType(f);
LTOVisibilityTypes vis = getLTOVisibilityType(f);
if (!f->isDeclaration() && lt != LTOInternalLinkage
&& strncmp (f->getName().c_str(), "llvm.", 5)) {
int alignment = ( 16 > f->getAlignment() ? 16 : f->getAlignment());
LLVMSymbol *newSymbol = new LLVMSymbol(lt, vis, f, f->getName(),
mangler.getValueName(f),
Log2_32(alignment));
symbols[newSymbol->getMangledName()] = newSymbol;
allSymbols[newSymbol->getMangledName()] = newSymbol;
}
// Collect external symbols referenced by this function.
for (Function::iterator b = f->begin(), fe = f->end(); b != fe; ++b)
for (BasicBlock::iterator i = b->begin(), be = b->end();
i != be; ++i) {
for (unsigned count = 0, total = i->getNumOperands();
count != total; ++count)
findExternalRefs(i->getOperand(count), references, mangler);
}
}
for (Module::global_iterator v = m->global_begin(), e = m->global_end();
v != e; ++v) {
LTOLinkageTypes lt = getLTOLinkageType(v);
LTOVisibilityTypes vis = getLTOVisibilityType(v);
if (!v->isDeclaration() && lt != LTOInternalLinkage
&& strncmp (v->getName().c_str(), "llvm.", 5)) {
const TargetData *TD = Target->getTargetData();
LLVMSymbol *newSymbol = new LLVMSymbol(lt, vis, v, v->getName(),
mangler.getValueName(v),
TD->getPreferredAlignmentLog(v));
symbols[newSymbol->getMangledName()] = newSymbol;
allSymbols[newSymbol->getMangledName()] = newSymbol;
for (unsigned count = 0, total = v->getNumOperands();
count != total; ++count)
findExternalRefs(v->getOperand(count), references, mangler);
}
}
return LTO_READ_SUCCESS;
}
/// Get TargetMachine.
/// Use module M to find appropriate Target.
void
LTO::getTarget (Module *M) {
if (Target)
return;
std::string Err;
const TargetMachineRegistry::entry* March =
TargetMachineRegistry::getClosestStaticTargetForModule(*M, Err);
if (March == 0)
return;
// Create target
std::string Features;
Target = March->CtorFn(*M, Features);
}
/// Optimize module M using various IPO passes. Use exportList to
/// internalize selected symbols. Target platform is selected
/// based on information available to module M. No new target
/// features are selected.
enum LTOStatus
LTO::optimize(Module *M, std::ostream &Out,
std::vector<const char *> &exportList)
{
// Instantiate the pass manager to organize the passes.
PassManager Passes;
// Collect Target info
getTarget(M);
if (!Target)
return LTO_NO_TARGET;
// Start off with a verification pass.
Passes.add(createVerifierPass());
// Add an appropriate TargetData instance for this module...
Passes.add(new TargetData(*Target->getTargetData()));
// Internalize symbols if export list is nonemty
if (!exportList.empty())
Passes.add(createInternalizePass(exportList));
// Now that we internalized some globals, see if we can hack on them!
Passes.add(createGlobalOptimizerPass());
// Linking modules together can lead to duplicated global constants, only
// keep one copy of each constant...
Passes.add(createConstantMergePass());
// If the -s command line option was specified, strip the symbols out of the
// resulting program to make it smaller. -s is a GLD option that we are
// supporting.
Passes.add(createStripSymbolsPass());
// Propagate constants at call sites into the functions they call.
Passes.add(createIPConstantPropagationPass());
// Remove unused arguments from functions...
Passes.add(createDeadArgEliminationPass());
Passes.add(createFunctionInliningPass()); // Inline small functions
Passes.add(createPruneEHPass()); // Remove dead EH info
Passes.add(createGlobalDCEPass()); // Remove dead functions
// If we didn't decide to inline a function, check to see if we can
// transform it to pass arguments by value instead of by reference.
Passes.add(createArgumentPromotionPass());
// The IPO passes may leave cruft around. Clean up after them.
Passes.add(createInstructionCombiningPass());
Passes.add(createScalarReplAggregatesPass()); // Break up allocas
// Run a few AA driven optimizations here and now, to cleanup the code.
Passes.add(createGlobalsModRefPass()); // IP alias analysis
Passes.add(createLICMPass()); // Hoist loop invariants
Passes.add(createLoadValueNumberingPass()); // GVN for load instrs
Passes.add(createGCSEPass()); // Remove common subexprs
Passes.add(createDeadStoreEliminationPass()); // Nuke dead stores
// Cleanup and simplify the code after the scalar optimizations.
Passes.add(createInstructionCombiningPass());
// Delete basic blocks, which optimization passes may have killed...
Passes.add(createCFGSimplificationPass());
// Now that we have optimized the program, discard unreachable functions...
Passes.add(createGlobalDCEPass());
// Make sure everything is still good.
Passes.add(createVerifierPass());
FunctionPassManager *CodeGenPasses =
new FunctionPassManager(new ExistingModuleProvider(M));
CodeGenPasses->add(new TargetData(*Target->getTargetData()));
MachineCodeEmitter *MCE = 0;
switch (Target->addPassesToEmitFile(*CodeGenPasses, Out,
TargetMachine::AssemblyFile, true)) {
default:
case FileModel::Error:
return LTO_WRITE_FAILURE;
case FileModel::AsmFile:
break;
case FileModel::MachOFile:
MCE = AddMachOWriter(*CodeGenPasses, Out, *Target);
break;
case FileModel::ElfFile:
MCE = AddELFWriter(*CodeGenPasses, Out, *Target);
break;
}
if (Target->addPassesToEmitFileFinish(*CodeGenPasses, MCE, true))
return LTO_WRITE_FAILURE;
// Run our queue of passes all at once now, efficiently.
Passes.run(*M);
// Run the code generator, if present.
CodeGenPasses->doInitialization();
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I) {
if (!I->isDeclaration())
CodeGenPasses->run(*I);
}
CodeGenPasses->doFinalization();
return LTO_OPT_SUCCESS;
}
///Link all modules together and optimize them using IPO. Generate
/// native object file using OutputFilename
/// Return appropriate LTOStatus.
enum LTOStatus
LTO::optimizeModules(const std::string &OutputFilename,
std::vector<const char *> &exportList,
std::string &targetTriple,
bool saveTemps, const char *FinalOutputFilename)
{
if (modules.empty())
return LTO_NO_WORK;
std::ios::openmode io_mode =
std::ios::out | std::ios::trunc | std::ios::binary;
std::string *errMsg = NULL;
Module *bigOne = modules[0];
Linker theLinker("LinkTimeOptimizer", bigOne, false);
for (unsigned i = 1, e = modules.size(); i != e; ++i)
if (theLinker.LinkModules(bigOne, modules[i], errMsg))
return LTO_MODULE_MERGE_FAILURE;
// all modules have been handed off to the linker.
modules.clear();
sys::Path FinalOutputPath(FinalOutputFilename);
FinalOutputPath.eraseSuffix();
switch(CGModel) {
case LTO_CGM_Dynamic:
Target->setRelocationModel(Reloc::PIC_);
break;
case LTO_CGM_DynamicNoPIC:
Target->setRelocationModel(Reloc::DynamicNoPIC);
break;
case LTO_CGM_Static:
Target->setRelocationModel(Reloc::Static);
break;
}
if (saveTemps) {
std::string tempFileName(FinalOutputPath.c_str());
tempFileName += "0.bc";
std::ofstream Out(tempFileName.c_str(), io_mode);
WriteBitcodeToFile(bigOne, Out);
}
// Strip leading underscore because it was added to match names
// seen by linker.
for (unsigned i = 0, e = exportList.size(); i != e; ++i) {
const char *name = exportList[i];
NameToSymbolMap::iterator itr = allSymbols.find(name);
if (itr != allSymbols.end())
exportList[i] = allSymbols[name]->getName();
}
std::string ErrMsg;
sys::Path TempDir = sys::Path::GetTemporaryDirectory(&ErrMsg);
if (TempDir.isEmpty()) {
cerr << "lto: " << ErrMsg << "\n";
return LTO_WRITE_FAILURE;
}
sys::Path tmpAsmFilePath(TempDir);
if (!tmpAsmFilePath.appendComponent("lto")) {
cerr << "lto: " << ErrMsg << "\n";
TempDir.eraseFromDisk(true);
return LTO_WRITE_FAILURE;
}
if (tmpAsmFilePath.createTemporaryFileOnDisk(true, &ErrMsg)) {
cerr << "lto: " << ErrMsg << "\n";
TempDir.eraseFromDisk(true);
return LTO_WRITE_FAILURE;
}
sys::RemoveFileOnSignal(tmpAsmFilePath);
std::ofstream asmFile(tmpAsmFilePath.c_str(), io_mode);
if (!asmFile.is_open() || asmFile.bad()) {
if (tmpAsmFilePath.exists()) {
tmpAsmFilePath.eraseFromDisk();
TempDir.eraseFromDisk(true);
}
return LTO_WRITE_FAILURE;
}
enum LTOStatus status = optimize(bigOne, asmFile, exportList);
asmFile.close();
if (status != LTO_OPT_SUCCESS) {
tmpAsmFilePath.eraseFromDisk();
TempDir.eraseFromDisk(true);
return status;
}
if (saveTemps) {
std::string tempFileName(FinalOutputPath.c_str());
tempFileName += "1.bc";
std::ofstream Out(tempFileName.c_str(), io_mode);
WriteBitcodeToFile(bigOne, Out);
}
targetTriple = bigOne->getTargetTriple();
// Run GCC to assemble and link the program into native code.
//
// Note:
// We can't just assemble and link the file with the system assembler
// and linker because we don't know where to put the _start symbol.
// GCC mysteriously knows how to do it.
const sys::Path gcc = sys::Program::FindProgramByName("gcc");
if (gcc.isEmpty()) {
tmpAsmFilePath.eraseFromDisk();
TempDir.eraseFromDisk(true);
return LTO_ASM_FAILURE;
}
std::vector<const char*> args;
args.push_back(gcc.c_str());
args.push_back("-c");
args.push_back("-x");
args.push_back("assembler");
args.push_back("-o");
args.push_back(OutputFilename.c_str());
args.push_back(tmpAsmFilePath.c_str());
args.push_back(0);
if (sys::Program::ExecuteAndWait(gcc, &args[0], 0, 0, 1, 0, &ErrMsg)) {
cerr << "lto: " << ErrMsg << "\n";
return LTO_ASM_FAILURE;
}
tmpAsmFilePath.eraseFromDisk();
TempDir.eraseFromDisk(true);
return LTO_OPT_SUCCESS;
}
void LTO::printVersion() {
cl::PrintVersionMessage();
}
/// Unused pure-virtual destructor. Must remain empty.
LinkTimeOptimizer::~LinkTimeOptimizer() {}
/// Destruct LTO. Delete all modules, symbols and target.
LTO::~LTO() {
for (std::vector<Module *>::iterator itr = modules.begin(), e = modules.end();
itr != e; ++itr)
delete *itr;
modules.clear();
for (NameToSymbolMap::iterator itr = allSymbols.begin(), e = allSymbols.end();
itr != e; ++itr)
delete itr->second;
allSymbols.clear();
delete Target;
}