1 //===- Config.h -------------------------------------------------*- C++ -*-===//
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 #ifndef LLD_ELF_CONFIG_H
10 #define LLD_ELF_CONFIG_H
11
12 #include "lld/Common/ErrorHandler.h"
13 #include "llvm/ADT/MapVector.h"
14 #include "llvm/ADT/StringRef.h"
15 #include "llvm/ADT/StringSet.h"
16 #include "llvm/BinaryFormat/ELF.h"
17 #include "llvm/Support/CachePruning.h"
18 #include "llvm/Support/CodeGen.h"
19 #include "llvm/Support/Endian.h"
20 #include <atomic>
21 #include <vector>
22
23 namespace lld {
24 namespace elf {
25
26 class InputFile;
27 class InputSectionBase;
28
29 enum ELFKind {
30 ELFNoneKind,
31 ELF32LEKind,
32 ELF32BEKind,
33 ELF64LEKind,
34 ELF64BEKind
35 };
36
37 // For --build-id.
38 enum class BuildIdKind { None, Fast, Md5, Sha1, Hexstring, Uuid };
39
40 // For --discard-{all,locals,none}.
41 enum class DiscardPolicy { Default, All, Locals, None };
42
43 // For --icf={none,safe,all}.
44 enum class ICFLevel { None, Safe, All };
45
46 // For --strip-{all,debug}.
47 enum class StripPolicy { None, All, Debug };
48
49 // For --unresolved-symbols.
50 enum class UnresolvedPolicy { ReportError, Warn, Ignore };
51
52 // For --orphan-handling.
53 enum class OrphanHandlingPolicy { Place, Warn, Error };
54
55 // For --sort-section and linkerscript sorting rules.
56 enum class SortSectionPolicy { Default, None, Alignment, Name, Priority };
57
58 // For --target2
59 enum class Target2Policy { Abs, Rel, GotRel };
60
61 // For tracking ARM Float Argument PCS
62 enum class ARMVFPArgKind { Default, Base, VFP, ToolChain };
63
64 // For -z noseparate-code, -z separate-code and -z separate-loadable-segments.
65 enum class SeparateSegmentKind { None, Code, Loadable };
66
67 // For -z *stack
68 enum class GnuStackKind { None, Exec, NoExec };
69
70 struct SymbolVersion {
71 llvm::StringRef name;
72 bool isExternCpp;
73 bool hasWildcard;
74 };
75
76 // This struct contains symbols version definition that
77 // can be found in version script if it is used for link.
78 struct VersionDefinition {
79 llvm::StringRef name;
80 uint16_t id;
81 std::vector<SymbolVersion> patterns;
82 };
83
84 // This struct contains the global configuration for the linker.
85 // Most fields are direct mapping from the command line options
86 // and such fields have the same name as the corresponding options.
87 // Most fields are initialized by the driver.
88 struct Configuration {
89 uint8_t osabi = 0;
90 uint32_t andFeatures = 0;
91 llvm::CachePruningPolicy thinLTOCachePolicy;
92 llvm::StringMap<uint64_t> sectionStartMap;
93 llvm::StringRef chroot;
94 llvm::StringRef dynamicLinker;
95 llvm::StringRef dwoDir;
96 llvm::StringRef entry;
97 llvm::StringRef emulation;
98 llvm::StringRef fini;
99 llvm::StringRef init;
100 llvm::StringRef ltoAAPipeline;
101 llvm::StringRef ltoCSProfileFile;
102 llvm::StringRef ltoNewPmPasses;
103 llvm::StringRef ltoObjPath;
104 llvm::StringRef ltoSampleProfile;
105 llvm::StringRef mapFile;
106 llvm::StringRef outputFile;
107 llvm::StringRef optRemarksFilename;
108 llvm::StringRef optRemarksPasses;
109 llvm::StringRef optRemarksFormat;
110 llvm::StringRef progName;
111 llvm::StringRef printSymbolOrder;
112 llvm::StringRef soName;
113 llvm::StringRef sysroot;
114 llvm::StringRef thinLTOCacheDir;
115 llvm::StringRef thinLTOIndexOnlyArg;
116 std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace;
117 std::pair<llvm::StringRef, llvm::StringRef> thinLTOPrefixReplace;
118 std::string rpath;
119 std::vector<VersionDefinition> versionDefinitions;
120 std::vector<llvm::StringRef> auxiliaryList;
121 std::vector<llvm::StringRef> filterList;
122 std::vector<llvm::StringRef> searchPaths;
123 std::vector<llvm::StringRef> symbolOrderingFile;
124 std::vector<llvm::StringRef> undefined;
125 std::vector<SymbolVersion> dynamicList;
126 std::vector<uint8_t> buildIdVector;
127 llvm::MapVector<std::pair<const InputSectionBase *, const InputSectionBase *>,
128 uint64_t>
129 callGraphProfile;
130 bool allowMultipleDefinition;
131 bool allowShlibUndefined;
132 bool androidPackDynRelocs;
133 bool armHasBlx = false;
134 bool armHasMovtMovw = false;
135 bool armJ1J2BranchEncoding = false;
136 bool asNeeded = false;
137 bool bsymbolic;
138 bool bsymbolicFunctions;
139 bool callGraphProfileSort;
140 bool checkSections;
141 bool compressDebugSections;
142 bool cref;
143 bool defineCommon;
144 bool demangle = true;
145 bool dependentLibraries;
146 bool disableVerify;
147 bool ehFrameHdr;
148 bool emitLLVM;
149 bool emitRelocs;
150 bool enableNewDtags;
151 bool executeOnly;
152 bool exportDynamic;
153 bool fixCortexA53Errata843419;
154 bool fixCortexA8;
155 bool forceBTI;
156 bool formatBinary = false;
157 bool gcSections;
158 bool gdbIndex;
159 bool gnuHash = false;
160 bool gnuUnique;
161 bool hasDynamicList = false;
162 bool hasDynSymTab;
163 bool ignoreDataAddressEquality;
164 bool ignoreFunctionAddressEquality;
165 bool ltoCSProfileGenerate;
166 bool ltoDebugPassManager;
167 bool ltoNewPassManager;
168 bool mergeArmExidx;
169 bool mipsN32Abi = false;
170 bool mmapOutputFile;
171 bool nmagic;
172 bool noDynamicLinker = false;
173 bool noinhibitExec;
174 bool nostdlib;
175 bool oFormatBinary;
176 bool omagic;
177 bool optRemarksWithHotness;
178 bool pacPlt;
179 bool picThunk;
180 bool pie;
181 bool printGcSections;
182 bool printIcfSections;
183 bool relocatable;
184 bool relrPackDynRelocs;
185 bool saveTemps;
186 bool singleRoRx;
187 bool shared;
188 bool isStatic = false;
189 bool sysvHash = false;
190 bool target1Rel;
191 bool trace;
192 bool thinLTOEmitImportsFiles;
193 bool thinLTOIndexOnly;
194 bool tocOptimize;
195 bool undefinedVersion;
196 bool useAndroidRelrTags = false;
197 bool warnBackrefs;
198 bool warnCommon;
199 bool warnIfuncTextrel;
200 bool warnMissingEntry;
201 bool warnSymbolOrdering;
202 bool writeAddends;
203 bool zCombreloc;
204 bool zCopyreloc;
205 bool zForceIbt;
206 bool zGlobal;
207 bool zHazardplt;
208 bool zIfuncNoplt;
209 bool zInitfirst;
210 bool zInterpose;
211 bool zKeepTextSectionPrefix;
212 bool zNodefaultlib;
213 bool zNodelete;
214 bool zNodlopen;
215 bool zNow;
216 bool zOrigin;
217 bool zRelro;
218 bool zRodynamic;
219 bool zShstk;
220 bool zText;
221 bool zRetpolineplt;
222 bool zWxneeded;
223 DiscardPolicy discard;
224 GnuStackKind zGnustack;
225 ICFLevel icf;
226 OrphanHandlingPolicy orphanHandling;
227 SortSectionPolicy sortSection;
228 StripPolicy strip;
229 UnresolvedPolicy unresolvedSymbols;
230 Target2Policy target2;
231 ARMVFPArgKind armVFPArgs = ARMVFPArgKind::Default;
232 BuildIdKind buildId = BuildIdKind::None;
233 SeparateSegmentKind zSeparate;
234 ELFKind ekind = ELFNoneKind;
235 uint16_t emachine = llvm::ELF::EM_NONE;
236 llvm::Optional<uint64_t> imageBase;
237 uint64_t commonPageSize;
238 uint64_t maxPageSize;
239 uint64_t mipsGotSize;
240 uint64_t zStackSize;
241 unsigned ltoPartitions;
242 unsigned ltoo;
243 unsigned optimize;
244 unsigned thinLTOJobs;
245 int32_t splitStackAdjustSize;
246
247 // The following config options do not directly correspond to any
248 // particular command line options.
249
250 // True if we need to pass through relocations in input files to the
251 // output file. Usually false because we consume relocations.
252 bool copyRelocs;
253
254 // True if the target is ELF64. False if ELF32.
255 bool is64;
256
257 // True if the target is little-endian. False if big-endian.
258 bool isLE;
259
260 // endianness::little if isLE is true. endianness::big otherwise.
261 llvm::support::endianness endianness;
262
263 // True if the target is the little-endian MIPS64.
264 //
265 // The reason why we have this variable only for the MIPS is because
266 // we use this often. Some ELF headers for MIPS64EL are in a
267 // mixed-endian (which is horrible and I'd say that's a serious spec
268 // bug), and we need to know whether we are reading MIPS ELF files or
269 // not in various places.
270 //
271 // (Note that MIPS64EL is not a typo for MIPS64LE. This is the official
272 // name whatever that means. A fun hypothesis is that "EL" is short for
273 // little-endian written in the little-endian order, but I don't know
274 // if that's true.)
275 bool isMips64EL;
276
277 // True if we need to set the DF_STATIC_TLS flag to an output file,
278 // which works as a hint to the dynamic loader that the file contains
279 // code compiled with the static TLS model. The thread-local variable
280 // compiled with the static TLS model is faster but less flexible, and
281 // it may not be loaded using dlopen().
282 //
283 // We set this flag to true when we see a relocation for the static TLS
284 // model. Once this becomes true, it will never become false.
285 //
286 // Since the flag is updated by multi-threaded code, we use std::atomic.
287 // (Writing to a variable is not considered thread-safe even if the
288 // variable is boolean and we always set the same value from all threads.)
289 std::atomic<bool> hasStaticTlsModel{false};
290
291 // Holds set of ELF header flags for the target.
292 uint32_t eflags = 0;
293
294 // The ELF spec defines two types of relocation table entries, RELA and
295 // REL. RELA is a triplet of (offset, info, addend) while REL is a
296 // tuple of (offset, info). Addends for REL are implicit and read from
297 // the location where the relocations are applied. So, REL is more
298 // compact than RELA but requires a bit of more work to process.
299 //
300 // (From the linker writer's view, this distinction is not necessary.
301 // If the ELF had chosen whichever and sticked with it, it would have
302 // been easier to write code to process relocations, but it's too late
303 // to change the spec.)
304 //
305 // Each ABI defines its relocation type. IsRela is true if target
306 // uses RELA. As far as we know, all 64-bit ABIs are using RELA. A
307 // few 32-bit ABIs are using RELA too.
308 bool isRela;
309
310 // True if we are creating position-independent code.
311 bool isPic;
312
313 // 4 for ELF32, 8 for ELF64.
314 int wordsize;
315 };
316
317 // The only instance of Configuration struct.
318 extern Configuration *config;
319
320 // The first two elements of versionDefinitions represent VER_NDX_LOCAL and
321 // VER_NDX_GLOBAL. This helper returns other elements.
namedVersionDefs()322 static inline ArrayRef<VersionDefinition> namedVersionDefs() {
323 return llvm::makeArrayRef(config->versionDefinitions).slice(2);
324 }
325
errorOrWarn(const Twine & msg)326 static inline void errorOrWarn(const Twine &msg) {
327 if (!config->noinhibitExec)
328 error(msg);
329 else
330 warn(msg);
331 }
332 } // namespace elf
333 } // namespace lld
334
335 #endif
336