Bug Summary

File:tools/gold/gold-plugin.cpp
Location:line 712, column 37
Description:Called C++ object pointer is null

Annotated Source Code

1//===-- gold-plugin.cpp - Plugin to gold for Link Time Optimization ------===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is a gold plugin for LLVM. It provides an LLVM implementation of the
11// interface described in http://gcc.gnu.org/wiki/whopr/driver .
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Config/config.h" // plugin-api.h requires HAVE_STDINT_H
16#include "llvm/ADT/DenseSet.h"
17#include "llvm/ADT/StringSet.h"
18#include "llvm/Bitcode/ReaderWriter.h"
19#include "llvm/CodeGen/Analysis.h"
20#include "llvm/CodeGen/CommandFlags.h"
21#include "llvm/IR/Constants.h"
22#include "llvm/IR/LLVMContext.h"
23#include "llvm/IR/Module.h"
24#include "llvm/IR/Verifier.h"
25#include "llvm/Linker/Linker.h"
26#include "llvm/MC/SubtargetFeature.h"
27#include "llvm/Object/IRObjectFile.h"
28#include "llvm/PassManager.h"
29#include "llvm/Support/FormattedStream.h"
30#include "llvm/Support/Host.h"
31#include "llvm/Support/MemoryBuffer.h"
32#include "llvm/Support/TargetRegistry.h"
33#include "llvm/Support/TargetSelect.h"
34#include "llvm/Target/TargetLibraryInfo.h"
35#include "llvm/Transforms/IPO.h"
36#include "llvm/Transforms/IPO/PassManagerBuilder.h"
37#include "llvm/Transforms/Utils/GlobalStatus.h"
38#include "llvm/Transforms/Utils/ModuleUtils.h"
39#include "llvm/Transforms/Utils/ValueMapper.h"
40#include <list>
41#include <plugin-api.h>
42#include <system_error>
43#include <vector>
44
45#ifndef LDPO_PIE3
46// FIXME: remove this declaration when we stop maintaining Ubuntu Quantal and
47// Precise and Debian Wheezy (binutils 2.23 is required)
48# define LDPO_PIE3 3
49#endif
50
51using namespace llvm;
52
53namespace {
54struct claimed_file {
55 void *handle;
56 std::vector<ld_plugin_symbol> syms;
57};
58}
59
60static ld_plugin_status discard_message(int level, const char *format, ...) {
61 // Die loudly. Recent versions of Gold pass ld_plugin_message as the first
62 // callback in the transfer vector. This should never be called.
63 abort();
64}
65
66static ld_plugin_get_input_file get_input_file = nullptr;
67static ld_plugin_release_input_file release_input_file = nullptr;
68static ld_plugin_add_symbols add_symbols = nullptr;
69static ld_plugin_get_symbols get_symbols = nullptr;
70static ld_plugin_add_input_file add_input_file = nullptr;
71static ld_plugin_set_extra_library_path set_extra_library_path = nullptr;
72static ld_plugin_get_view get_view = nullptr;
73static ld_plugin_message message = discard_message;
74static Reloc::Model RelocationModel = Reloc::Default;
75static std::string output_name = "";
76static std::list<claimed_file> Modules;
77static std::vector<std::string> Cleanup;
78static llvm::TargetOptions TargetOpts;
79
80namespace options {
81 enum generate_bc { BC_NO, BC_ALSO, BC_ONLY };
82 static bool generate_api_file = false;
83 static generate_bc generate_bc_file = BC_NO;
84 static std::string bc_path;
85 static std::string obj_path;
86 static std::string extra_library_path;
87 static std::string triple;
88 static std::string mcpu;
89 // Additional options to pass into the code generator.
90 // Note: This array will contain all plugin options which are not claimed
91 // as plugin exclusive to pass to the code generator.
92 // For example, "generate-api-file" and "as"options are for the plugin
93 // use only and will not be passed.
94 static std::vector<const char *> extra;
95
96 static void process_plugin_option(const char* opt_)
97 {
98 if (opt_ == nullptr)
99 return;
100 llvm::StringRef opt = opt_;
101
102 if (opt == "generate-api-file") {
103 generate_api_file = true;
104 } else if (opt.startswith("mcpu=")) {
105 mcpu = opt.substr(strlen("mcpu="));
106 } else if (opt.startswith("extra-library-path=")) {
107 extra_library_path = opt.substr(strlen("extra_library_path="));
108 } else if (opt.startswith("mtriple=")) {
109 triple = opt.substr(strlen("mtriple="));
110 } else if (opt.startswith("obj-path=")) {
111 obj_path = opt.substr(strlen("obj-path="));
112 } else if (opt == "emit-llvm") {
113 generate_bc_file = BC_ONLY;
114 } else if (opt == "also-emit-llvm") {
115 generate_bc_file = BC_ALSO;
116 } else if (opt.startswith("also-emit-llvm=")) {
117 llvm::StringRef path = opt.substr(strlen("also-emit-llvm="));
118 generate_bc_file = BC_ALSO;
119 if (!bc_path.empty()) {
120 message(LDPL_WARNING, "Path to the output IL file specified twice. "
121 "Discarding %s",
122 opt_);
123 } else {
124 bc_path = path;
125 }
126 } else {
127 // Save this option to pass to the code generator.
128 // ParseCommandLineOptions() expects argv[0] to be program name. Lazily
129 // add that.
130 if (extra.empty())
131 extra.push_back("LLVMgold");
132
133 extra.push_back(opt_);
134 }
135 }
136}
137
138static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
139 int *claimed);
140static ld_plugin_status all_symbols_read_hook(void);
141static ld_plugin_status cleanup_hook(void);
142
143extern "C" ld_plugin_status onload(ld_plugin_tv *tv);
144ld_plugin_status onload(ld_plugin_tv *tv) {
145 InitializeAllTargetInfos();
146 InitializeAllTargets();
147 InitializeAllTargetMCs();
148 InitializeAllAsmParsers();
149 InitializeAllAsmPrinters();
150
151 // We're given a pointer to the first transfer vector. We read through them
152 // until we find one where tv_tag == LDPT_NULL. The REGISTER_* tagged values
153 // contain pointers to functions that we need to call to register our own
154 // hooks. The others are addresses of functions we can use to call into gold
155 // for services.
156
157 bool registeredClaimFile = false;
158 bool RegisteredAllSymbolsRead = false;
159
160 for (; tv->tv_tag != LDPT_NULL; ++tv) {
161 switch (tv->tv_tag) {
162 case LDPT_OUTPUT_NAME:
163 output_name = tv->tv_u.tv_string;
164 break;
165 case LDPT_LINKER_OUTPUT:
166 switch (tv->tv_u.tv_val) {
167 case LDPO_REL: // .o
168 case LDPO_DYN: // .so
169 case LDPO_PIE3: // position independent executable
170 RelocationModel = Reloc::PIC_;
171 break;
172 case LDPO_EXEC: // .exe
173 RelocationModel = Reloc::Static;
174 break;
175 default:
176 message(LDPL_ERROR, "Unknown output file type %d", tv->tv_u.tv_val);
177 return LDPS_ERR;
178 }
179 break;
180 case LDPT_OPTION:
181 options::process_plugin_option(tv->tv_u.tv_string);
182 break;
183 case LDPT_REGISTER_CLAIM_FILE_HOOK: {
184 ld_plugin_register_claim_file callback;
185 callback = tv->tv_u.tv_register_claim_file;
186
187 if (callback(claim_file_hook) != LDPS_OK)
188 return LDPS_ERR;
189
190 registeredClaimFile = true;
191 } break;
192 case LDPT_REGISTER_ALL_SYMBOLS_READ_HOOK: {
193 ld_plugin_register_all_symbols_read callback;
194 callback = tv->tv_u.tv_register_all_symbols_read;
195
196 if (callback(all_symbols_read_hook) != LDPS_OK)
197 return LDPS_ERR;
198
199 RegisteredAllSymbolsRead = true;
200 } break;
201 case LDPT_REGISTER_CLEANUP_HOOK: {
202 ld_plugin_register_cleanup callback;
203 callback = tv->tv_u.tv_register_cleanup;
204
205 if (callback(cleanup_hook) != LDPS_OK)
206 return LDPS_ERR;
207 } break;
208 case LDPT_GET_INPUT_FILE:
209 get_input_file = tv->tv_u.tv_get_input_file;
210 break;
211 case LDPT_RELEASE_INPUT_FILE:
212 release_input_file = tv->tv_u.tv_release_input_file;
213 break;
214 case LDPT_ADD_SYMBOLS:
215 add_symbols = tv->tv_u.tv_add_symbols;
216 break;
217 case LDPT_GET_SYMBOLS_V2:
218 get_symbols = tv->tv_u.tv_get_symbols;
219 break;
220 case LDPT_ADD_INPUT_FILE:
221 add_input_file = tv->tv_u.tv_add_input_file;
222 break;
223 case LDPT_SET_EXTRA_LIBRARY_PATH:
224 set_extra_library_path = tv->tv_u.tv_set_extra_library_path;
225 break;
226 case LDPT_GET_VIEW:
227 get_view = tv->tv_u.tv_get_view;
228 break;
229 case LDPT_MESSAGE:
230 message = tv->tv_u.tv_message;
231 break;
232 default:
233 break;
234 }
235 }
236
237 if (!registeredClaimFile) {
238 message(LDPL_ERROR, "register_claim_file not passed to LLVMgold.");
239 return LDPS_ERR;
240 }
241 if (!add_symbols) {
242 message(LDPL_ERROR, "add_symbols not passed to LLVMgold.");
243 return LDPS_ERR;
244 }
245
246 if (!RegisteredAllSymbolsRead)
247 return LDPS_OK;
248
249 if (!get_input_file) {
250 message(LDPL_ERROR, "get_input_file not passed to LLVMgold.");
251 return LDPS_ERR;
252 }
253 if (!release_input_file) {
254 message(LDPL_ERROR, "relesase_input_file not passed to LLVMgold.");
255 return LDPS_ERR;
256 }
257
258 return LDPS_OK;
259}
260
261static const GlobalObject *getBaseObject(const GlobalValue &GV) {
262 if (auto *GA = dyn_cast<GlobalAlias>(&GV))
263 return GA->getBaseObject();
264 return cast<GlobalObject>(&GV);
265}
266
267/// Called by gold to see whether this file is one that our plugin can handle.
268/// We'll try to open it and register all the symbols with add_symbol if
269/// possible.
270static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
271 int *claimed) {
272 LLVMContext Context;
273 MemoryBufferRef BufferRef;
274 std::unique_ptr<MemoryBuffer> Buffer;
275 if (get_view) {
276 const void *view;
277 if (get_view(file->handle, &view) != LDPS_OK) {
278 message(LDPL_ERROR, "Failed to get a view of %s", file->name);
279 return LDPS_ERR;
280 }
281 BufferRef = MemoryBufferRef(StringRef((const char *)view, file->filesize), "");
282 } else {
283 int64_t offset = 0;
284 // Gold has found what might be IR part-way inside of a file, such as
285 // an .a archive.
286 if (file->offset) {
287 offset = file->offset;
288 }
289 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr =
290 MemoryBuffer::getOpenFileSlice(file->fd, file->name, file->filesize,
291 offset);
292 if (std::error_code EC = BufferOrErr.getError()) {
293 message(LDPL_ERROR, EC.message().c_str());
294 return LDPS_ERR;
295 }
296 Buffer = std::move(BufferOrErr.get());
297 BufferRef = Buffer->getMemBufferRef();
298 }
299
300 ErrorOr<std::unique_ptr<object::IRObjectFile>> ObjOrErr =
301 object::IRObjectFile::createIRObjectFile(BufferRef, Context);
302 std::error_code EC = ObjOrErr.getError();
303 if (EC == BitcodeError::InvalidBitcodeSignature ||
304 EC == object::object_error::invalid_file_type ||
305 EC == object::object_error::bitcode_section_not_found)
306 return LDPS_OK;
307
308 *claimed = 1;
309
310 if (EC) {
311 message(LDPL_ERROR, "LLVM gold plugin has failed to create LTO module: %s",
312 EC.message().c_str());
313 return LDPS_ERR;
314 }
315 std::unique_ptr<object::IRObjectFile> Obj = std::move(*ObjOrErr);
316
317 Modules.resize(Modules.size() + 1);
318 claimed_file &cf = Modules.back();
319
320 cf.handle = file->handle;
321
322 for (auto &Sym : Obj->symbols()) {
323 uint32_t Symflags = Sym.getFlags();
324 if (!(Symflags & object::BasicSymbolRef::SF_Global))
325 continue;
326
327 if (Symflags & object::BasicSymbolRef::SF_FormatSpecific)
328 continue;
329
330 cf.syms.push_back(ld_plugin_symbol());
331 ld_plugin_symbol &sym = cf.syms.back();
332 sym.version = nullptr;
333
334 SmallString<64> Name;
335 {
336 raw_svector_ostream OS(Name);
337 Sym.printName(OS);
338 }
339 sym.name = strdup(Name.c_str());
340
341 const GlobalValue *GV = Obj->getSymbolGV(Sym.getRawDataRefImpl());
342
343 sym.visibility = LDPV_DEFAULT;
344 if (GV) {
345 switch (GV->getVisibility()) {
346 case GlobalValue::DefaultVisibility:
347 sym.visibility = LDPV_DEFAULT;
348 break;
349 case GlobalValue::HiddenVisibility:
350 sym.visibility = LDPV_HIDDEN;
351 break;
352 case GlobalValue::ProtectedVisibility:
353 sym.visibility = LDPV_PROTECTED;
354 break;
355 }
356 }
357
358 if (Symflags & object::BasicSymbolRef::SF_Undefined) {
359 sym.def = LDPK_UNDEF;
360 if (GV && GV->hasExternalWeakLinkage())
361 sym.def = LDPK_WEAKUNDEF;
362 } else {
363 sym.def = LDPK_DEF;
364 if (GV) {
365 assert(!GV->hasExternalWeakLinkage() &&((!GV->hasExternalWeakLinkage() && !GV->hasAvailableExternallyLinkage
() && "Not a declaration!") ? static_cast<void>
(0) : __assert_fail ("!GV->hasExternalWeakLinkage() && !GV->hasAvailableExternallyLinkage() && \"Not a declaration!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 366, __PRETTY_FUNCTION__))
366 !GV->hasAvailableExternallyLinkage() && "Not a declaration!")((!GV->hasExternalWeakLinkage() && !GV->hasAvailableExternallyLinkage
() && "Not a declaration!") ? static_cast<void>
(0) : __assert_fail ("!GV->hasExternalWeakLinkage() && !GV->hasAvailableExternallyLinkage() && \"Not a declaration!\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 366, __PRETTY_FUNCTION__));
367 if (GV->hasCommonLinkage())
368 sym.def = LDPK_COMMON;
369 else if (GV->isWeakForLinker())
370 sym.def = LDPK_WEAKDEF;
371 }
372 }
373
374 sym.size = 0;
375 sym.comdat_key = nullptr;
376 if (GV) {
377 const GlobalObject *Base = getBaseObject(*GV);
378 if (!Base)
379 message(LDPL_FATAL, "Unable to determine comdat of alias!");
380 const Comdat *C = Base->getComdat();
381 if (C)
382 sym.comdat_key = strdup(C->getName().str().c_str());
383 else if (Base->hasWeakLinkage() || Base->hasLinkOnceLinkage())
384 sym.comdat_key = strdup(sym.name);
385 }
386
387 sym.resolution = LDPR_UNKNOWN;
388 }
389
390 if (!cf.syms.empty()) {
391 if (add_symbols(cf.handle, cf.syms.size(), &cf.syms[0]) != LDPS_OK) {
392 message(LDPL_ERROR, "Unable to add symbols!");
393 return LDPS_ERR;
394 }
395 }
396
397 return LDPS_OK;
398}
399
400static void keepGlobalValue(GlobalValue &GV,
401 std::vector<GlobalAlias *> &KeptAliases) {
402 assert(!GV.hasLocalLinkage())((!GV.hasLocalLinkage()) ? static_cast<void> (0) : __assert_fail
("!GV.hasLocalLinkage()", "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 402, __PRETTY_FUNCTION__));
403
404 if (auto *GA = dyn_cast<GlobalAlias>(&GV))
405 KeptAliases.push_back(GA);
406
407 switch (GV.getLinkage()) {
408 default:
409 break;
410 case GlobalValue::LinkOnceAnyLinkage:
411 GV.setLinkage(GlobalValue::WeakAnyLinkage);
412 break;
413 case GlobalValue::LinkOnceODRLinkage:
414 GV.setLinkage(GlobalValue::WeakODRLinkage);
415 break;
416 }
417
418 assert(!GV.isDiscardableIfUnused())((!GV.isDiscardableIfUnused()) ? static_cast<void> (0) :
__assert_fail ("!GV.isDiscardableIfUnused()", "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 418, __PRETTY_FUNCTION__));
419}
420
421static void internalize(GlobalValue &GV) {
422 if (GV.isDeclarationForLinker())
423 return; // We get here if there is a matching asm definition.
424 if (!GV.hasLocalLinkage())
425 GV.setLinkage(GlobalValue::InternalLinkage);
426}
427
428static void drop(GlobalValue &GV) {
429 if (auto *F = dyn_cast<Function>(&GV)) {
430 F->deleteBody();
431 F->setComdat(nullptr); // Should deleteBody do this?
432 return;
433 }
434
435 if (auto *Var = dyn_cast<GlobalVariable>(&GV)) {
436 Var->setInitializer(nullptr);
437 Var->setLinkage(
438 GlobalValue::ExternalLinkage); // Should setInitializer do this?
439 Var->setComdat(nullptr); // and this?
440 return;
441 }
442
443 auto &Alias = cast<GlobalAlias>(GV);
444 Module &M = *Alias.getParent();
445 PointerType &Ty = *cast<PointerType>(Alias.getType());
446 GlobalValue::LinkageTypes L = Alias.getLinkage();
447 auto *Var =
448 new GlobalVariable(M, Ty.getElementType(), /*isConstant*/ false, L,
449 /*Initializer*/ nullptr);
450 Var->takeName(&Alias);
451 Alias.replaceAllUsesWith(Var);
452 Alias.eraseFromParent();
453}
454
455static const char *getResolutionName(ld_plugin_symbol_resolution R) {
456 switch (R) {
457 case LDPR_UNKNOWN:
458 return "UNKNOWN";
459 case LDPR_UNDEF:
460 return "UNDEF";
461 case LDPR_PREVAILING_DEF:
462 return "PREVAILING_DEF";
463 case LDPR_PREVAILING_DEF_IRONLY:
464 return "PREVAILING_DEF_IRONLY";
465 case LDPR_PREEMPTED_REG:
466 return "PREEMPTED_REG";
467 case LDPR_PREEMPTED_IR:
468 return "PREEMPTED_IR";
469 case LDPR_RESOLVED_IR:
470 return "RESOLVED_IR";
471 case LDPR_RESOLVED_EXEC:
472 return "RESOLVED_EXEC";
473 case LDPR_RESOLVED_DYN:
474 return "RESOLVED_DYN";
475 case LDPR_PREVAILING_DEF_IRONLY_EXP:
476 return "PREVAILING_DEF_IRONLY_EXP";
477 }
478 llvm_unreachable("Unknown resolution")::llvm::llvm_unreachable_internal("Unknown resolution", "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 478);
479}
480
481static GlobalObject *makeInternalReplacement(GlobalObject *GO) {
482 Module *M = GO->getParent();
483 GlobalObject *Ret;
484 if (auto *F = dyn_cast<Function>(GO)) {
485 if (F->isMaterializable()) {
486 if (F->materialize())
487 message(LDPL_FATAL, "LLVM gold plugin has failed to read a function");
488
489 }
490
491 auto *NewF = Function::Create(F->getFunctionType(), F->getLinkage(),
492 F->getName(), M);
493
494 ValueToValueMapTy VM;
495 Function::arg_iterator NewI = NewF->arg_begin();
496 for (auto &Arg : F->args()) {
497 NewI->setName(Arg.getName());
498 VM[&Arg] = NewI;
499 ++NewI;
500 }
501
502 NewF->getBasicBlockList().splice(NewF->end(), F->getBasicBlockList());
503 for (auto &BB : *NewF) {
504 for (auto &Inst : BB)
505 RemapInstruction(&Inst, VM, RF_IgnoreMissingEntries);
506 }
507
508 Ret = NewF;
509 F->deleteBody();
510 } else {
511 auto *Var = cast<GlobalVariable>(GO);
512 Ret = new GlobalVariable(
513 *M, Var->getType()->getElementType(), Var->isConstant(),
514 Var->getLinkage(), Var->getInitializer(), Var->getName(),
515 nullptr, Var->getThreadLocalMode(), Var->getType()->getAddressSpace(),
516 Var->isExternallyInitialized());
517 Var->setInitializer(nullptr);
518 }
519 Ret->copyAttributesFrom(GO);
520 Ret->setLinkage(GlobalValue::InternalLinkage);
521 Ret->setComdat(GO->getComdat());
522
523 return Ret;
524}
525
526namespace {
527class LocalValueMaterializer : public ValueMaterializer {
528 DenseSet<GlobalValue *> &Dropped;
529
530public:
531 LocalValueMaterializer(DenseSet<GlobalValue *> &Dropped) : Dropped(Dropped) {}
532 Value *materializeValueFor(Value *V) override;
533};
534}
535
536Value *LocalValueMaterializer::materializeValueFor(Value *V) {
537 auto *GV = dyn_cast<GlobalValue>(V);
538 if (!GV)
539 return nullptr;
540 if (!Dropped.count(GV))
541 return nullptr;
542 assert(!isa<GlobalAlias>(GV) && "Found alias point to weak alias.")((!isa<GlobalAlias>(GV) && "Found alias point to weak alias."
) ? static_cast<void> (0) : __assert_fail ("!isa<GlobalAlias>(GV) && \"Found alias point to weak alias.\""
, "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 542, __PRETTY_FUNCTION__));
543 return makeInternalReplacement(cast<GlobalObject>(GV));
544}
545
546static Constant *mapConstantToLocalCopy(Constant *C, ValueToValueMapTy &VM,
547 LocalValueMaterializer *Materializer) {
548 return MapValue(C, VM, RF_IgnoreMissingEntries, nullptr, Materializer);
549}
550
551static std::unique_ptr<Module>
552getModuleForFile(LLVMContext &Context, claimed_file &F, raw_fd_ostream *ApiFile,
553 StringSet<> &Internalize, StringSet<> &Maybe) {
554 ld_plugin_input_file File;
555 if (get_input_file(F.handle, &File) != LDPS_OK)
556 message(LDPL_FATAL, "Failed to get file information");
557
558 if (get_symbols(F.handle, F.syms.size(), &F.syms[0]) != LDPS_OK)
559 message(LDPL_FATAL, "Failed to get symbol information");
560
561 const void *View;
562 if (get_view(F.handle, &View) != LDPS_OK)
563 message(LDPL_FATAL, "Failed to get a view of file");
564
565 llvm::ErrorOr<MemoryBufferRef> MBOrErr =
566 object::IRObjectFile::findBitcodeInMemBuffer(
567 MemoryBufferRef(StringRef((const char *)View, File.filesize), ""));
568 if (std::error_code EC = MBOrErr.getError())
569 message(LDPL_FATAL, "Could not read bitcode from file : %s",
570 EC.message().c_str());
571
572 std::unique_ptr<MemoryBuffer> Buffer =
573 MemoryBuffer::getMemBuffer(MBOrErr->getBuffer(), "", false);
574
575 if (release_input_file(F.handle) != LDPS_OK)
576 message(LDPL_FATAL, "Failed to release file information");
577
578 ErrorOr<Module *> MOrErr = getLazyBitcodeModule(std::move(Buffer), Context);
579
580 if (std::error_code EC = MOrErr.getError())
581 message(LDPL_FATAL, "Could not read bitcode from file : %s",
582 EC.message().c_str());
583
584 std::unique_ptr<Module> M(MOrErr.get());
585
586 SmallPtrSet<GlobalValue *, 8> Used;
587 collectUsedGlobalVariables(*M, Used, /*CompilerUsed*/ false);
588
589 DenseSet<GlobalValue *> Drop;
590 std::vector<GlobalAlias *> KeptAliases;
591 for (ld_plugin_symbol &Sym : F.syms) {
592 ld_plugin_symbol_resolution Resolution =
593 (ld_plugin_symbol_resolution)Sym.resolution;
594
595 if (options::generate_api_file)
596 *ApiFile << Sym.name << ' ' << getResolutionName(Resolution) << '\n';
597
598 GlobalValue *GV = M->getNamedValue(Sym.name);
599 if (!GV)
600 continue; // Asm symbol.
601
602 if (Resolution != LDPR_PREVAILING_DEF_IRONLY && GV->hasCommonLinkage()) {
603 // Common linkage is special. There is no single symbol that wins the
604 // resolution. Instead we have to collect the maximum alignment and size.
605 // The IR linker does that for us if we just pass it every common GV.
606 // We still have to keep track of LDPR_PREVAILING_DEF_IRONLY so we
607 // internalize once the IR linker has done its job.
608 continue;
609 }
610
611 switch (Resolution) {
612 case LDPR_UNKNOWN:
613 llvm_unreachable("Unexpected resolution")::llvm::llvm_unreachable_internal("Unexpected resolution", "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 613);
614
615 case LDPR_RESOLVED_IR:
616 case LDPR_RESOLVED_EXEC:
617 case LDPR_RESOLVED_DYN:
618 case LDPR_UNDEF:
619 assert(GV->isDeclarationForLinker())((GV->isDeclarationForLinker()) ? static_cast<void> (
0) : __assert_fail ("GV->isDeclarationForLinker()", "/tmp/buildd/llvm-toolchain-snapshot-3.6~svn220848/tools/gold/gold-plugin.cpp"
, 619, __PRETTY_FUNCTION__));
620 break;
621
622 case LDPR_PREVAILING_DEF_IRONLY: {
623 keepGlobalValue(*GV, KeptAliases);
624 if (!Used.count(GV)) {
625 // Since we use the regular lib/Linker, we cannot just internalize GV
626 // now or it will not be copied to the merged module. Instead we force
627 // it to be copied and then internalize it.
628 Internalize.insert(Sym.name);
629 }
630 break;
631 }
632
633 case LDPR_PREVAILING_DEF:
634 keepGlobalValue(*GV, KeptAliases);
635 break;
636
637 case LDPR_PREEMPTED_IR:
638 // Gold might have selected a linkonce_odr and preempted a weak_odr.
639 // In that case we have to make sure we don't end up internalizing it.
640 if (!GV->isDiscardableIfUnused())
641 Maybe.erase(Sym.name);
642
643 // fall-through
644 case LDPR_PREEMPTED_REG:
645 Drop.insert(GV);
646 break;
647
648 case LDPR_PREVAILING_DEF_IRONLY_EXP: {
649 // We can only check for address uses after we merge the modules. The
650 // reason is that this GV might have a copy in another module
651 // and in that module the address might be significant, but that
652 // copy will be LDPR_PREEMPTED_IR.
653 if (GV->hasLinkOnceODRLinkage())
654 Maybe.insert(Sym.name);
655 keepGlobalValue(*GV, KeptAliases);
656 break;
657 }
658 }
659
660 free(Sym.name);
661 free(Sym.comdat_key);
662 Sym.name = nullptr;
663 Sym.comdat_key = nullptr;
664 }
665
666 ValueToValueMapTy VM;
667 LocalValueMaterializer Materializer(Drop);
668 for (GlobalAlias *GA : KeptAliases) {
669 // Gold told us to keep GA. It is possible that a GV usied in the aliasee
670 // expression is being dropped. If that is the case, that GV must be copied.
671 Constant *Aliasee = GA->getAliasee();
672 Constant *Replacement = mapConstantToLocalCopy(Aliasee, VM, &Materializer);
673 if (Aliasee != Replacement)
674 GA->setAliasee(Replacement);
675 }
676
677 for (auto *GV : Drop)
678 drop(*GV);
679
680 return M;
681}
682
683static void runLTOPasses(Module &M, TargetMachine &TM) {
684 PassManager passes;
685 PassManagerBuilder PMB;
686 PMB.LibraryInfo = new TargetLibraryInfo(Triple(TM.getTargetTriple()));
687 PMB.Inliner = createFunctionInliningPass();
688 PMB.VerifyInput = true;
689 PMB.VerifyOutput = true;
690 PMB.populateLTOPassManager(passes, &TM);
691 passes.run(M);
692}
693
694static void codegen(Module &M) {
695 const std::string &TripleStr = M.getTargetTriple();
696 Triple TheTriple(TripleStr);
697
698 std::string ErrMsg;
699 const Target *TheTarget = TargetRegistry::lookupTarget(TripleStr, ErrMsg);
9
←
'TheTarget' initialized here
→
700 if (!TheTarget)
10
←
Assuming 'TheTarget' is null
→
11
←
Taking true branch
→
701 message(LDPL_FATAL, "Target not found: %s", ErrMsg.c_str());
702
703 if (unsigned NumOpts = options::extra.size())
12
←
Assuming 'NumOpts' is 0
→
13
←
Taking false branch
→
704 cl::ParseCommandLineOptions(NumOpts, &options::extra[0]);
705
706 SubtargetFeatures Features;
707 Features.getDefaultSubtargetFeatures(TheTriple);
708 for (const std::string &A : MAttrs)
709 Features.AddFeature(A);
710
711 TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
712 std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
14
←
Called C++ object pointer is null
713 TripleStr, options::mcpu, Features.getString(), Options, RelocationModel,
714 CodeModel::Default, CodeGenOpt::Aggressive));
715
716 runLTOPasses(M, *TM);
717
718 PassManager CodeGenPasses;
719 CodeGenPasses.add(new DataLayoutPass());
720
721 SmallString<128> Filename;
722 int FD;
723 if (options::obj_path.empty()) {
724 std::error_code EC =
725 sys::fs::createTemporaryFile("lto-llvm", "o", FD, Filename);
726 if (EC)
727 message(LDPL_FATAL, "Could not create temorary file: %s",
728 EC.message().c_str());
729 } else {
730 Filename = options::obj_path;
731 std::error_code EC =
732 sys::fs::openFileForWrite(Filename.c_str(), FD, sys::fs::F_None);
733 if (EC)
734 message(LDPL_FATAL, "Could not open file: %s", EC.message().c_str());
735 }
736
737 {
738 raw_fd_ostream OS(FD, true);
739 formatted_raw_ostream FOS(OS);
740
741 if (TM->addPassesToEmitFile(CodeGenPasses, FOS,
742 TargetMachine::CGFT_ObjectFile))
743 message(LDPL_FATAL, "Failed to setup codegen");
744 CodeGenPasses.run(M);
745 }
746
747 if (add_input_file(Filename.c_str()) != LDPS_OK)
748 message(LDPL_FATAL,
749 "Unable to add .o file to the link. File left behind in: %s",
750 Filename.c_str());
751
752 if (options::obj_path.empty())
753 Cleanup.push_back(Filename.c_str());
754}
755
756/// gold informs us that all symbols have been read. At this point, we use
757/// get_symbols to see if any of our definitions have been overridden by a
758/// native object file. Then, perform optimization and codegen.
759static ld_plugin_status allSymbolsReadHook(raw_fd_ostream *ApiFile) {
760 if (Modules.empty())
5
←
Taking false branch
→
761 return LDPS_OK;
762
763 LLVMContext Context;
764 std::unique_ptr<Module> Combined(new Module("ld-temp.o", Context));
765 Linker L(Combined.get());
766
767 std::string DefaultTriple = sys::getDefaultTargetTriple();
768
769 StringSet<> Internalize;
770 StringSet<> Maybe;
771 for (claimed_file &F : Modules) {
772 std::unique_ptr<Module> M =
773 getModuleForFile(Context, F, ApiFile, Internalize, Maybe);
774 if (!options::triple.empty())
775 M->setTargetTriple(options::triple.c_str());
776 else if (M->getTargetTriple().empty()) {
777 M->setTargetTriple(DefaultTriple);
778 }
779
780 if (L.linkInModule(M.get()))
781 message(LDPL_FATAL, "Failed to link module");
782 }
783
784 for (const auto &Name : Internalize) {
785 GlobalValue *GV = Combined->getNamedValue(Name.first());
786 if (GV)
787 internalize(*GV);
788 }
789
790 for (const auto &Name : Maybe) {
791 GlobalValue *GV = Combined->getNamedValue(Name.first());
792 if (!GV)
793 continue;
794 GV->setLinkage(GlobalValue::LinkOnceODRLinkage);
795 if (canBeOmittedFromSymbolTable(GV))
796 internalize(*GV);
797 }
798
799 if (options::generate_bc_file != options::BC_NO) {
6
←
Assuming 'generate_bc_file' is equal to BC_NO
→
7
←
Taking false branch
→
800 std::string path;
801 if (options::generate_bc_file == options::BC_ONLY)
802 path = output_name;
803 else if (!options::bc_path.empty())
804 path = options::bc_path;
805 else
806 path = output_name + ".bc";
807 {
808 std::error_code EC;
809 raw_fd_ostream OS(path, EC, sys::fs::OpenFlags::F_None);
810 if (EC)
811 message(LDPL_FATAL, "Failed to write the output file.");
812 WriteBitcodeToFile(L.getModule(), OS);
813 }
814 if (options::generate_bc_file == options::BC_ONLY)
815 return LDPS_OK;
816 }
817
818 codegen(*L.getModule());
8
←
Calling 'codegen'
→
819
820 if (!options::extra_library_path.empty() &&
821 set_extra_library_path(options::extra_library_path.c_str()) != LDPS_OK)
822 message(LDPL_FATAL, "Unable to set the extra library path.");
823
824 return LDPS_OK;
825}
826
827static ld_plugin_status all_symbols_read_hook(void) {
828 ld_plugin_status Ret;
829 if (!options::generate_api_file) {
1
Assuming 'generate_api_file' is not equal to 0
→
2
←
Taking false branch
→
830 Ret = allSymbolsReadHook(nullptr);
831 } else {
832 std::error_code EC;
833 raw_fd_ostream ApiFile("apifile.txt", EC, sys::fs::F_None);
834 if (EC)
3
←
Taking false branch
→
835 message(LDPL_FATAL, "Unable to open apifile.txt for writing: %s",
836 EC.message().c_str());
837 Ret = allSymbolsReadHook(&ApiFile);
4
←
Calling 'allSymbolsReadHook'
→
838 }
839
840 if (options::generate_bc_file == options::BC_ONLY)
841 exit(0);
842
843 return Ret;
844}
845
846static ld_plugin_status cleanup_hook(void) {
847 for (std::string &Name : Cleanup) {
848 std::error_code EC = sys::fs::remove(Name);
849 if (EC)
850 message(LDPL_ERROR, "Failed to delete '%s': %s", Name.c_str(),
851 EC.message().c_str());
852 }
853
854 return LDPS_OK;
855}