Bug Summary

File:include/llvm/Support/Error.h
Warning:line 201, column 5
Potential leak of memory pointed to by 'Payload._M_t._M_head_impl'

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ELF.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-8/lib/clang/8.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/lib/Object -I /build/llvm-toolchain-snapshot-8~svn350071/lib/Object -I /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn350071/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-8~svn350071/build-llvm/lib/Object -fdebug-prefix-map=/build/llvm-toolchain-snapshot-8~svn350071=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-12-27-042839-1215-1 -x c++ /build/llvm-toolchain-snapshot-8~svn350071/lib/Object/ELF.cpp -faddrsig

/build/llvm-toolchain-snapshot-8~svn350071/lib/Object/ELF.cpp

1//===- ELF.cpp - ELF object file implementation ---------------------------===//
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#include "llvm/Object/ELF.h"
11#include "llvm/BinaryFormat/ELF.h"
12#include "llvm/Support/LEB128.h"
13
14using namespace llvm;
15using namespace object;
16
17#define STRINGIFY_ENUM_CASE(ns, name)case ns::name: return "name"; \
18 case ns::name: \
19 return #name;
20
21#define ELF_RELOC(name, value) STRINGIFY_ENUM_CASE(ELF, name)case ELF::name: return "name";
22
23StringRef llvm::object::getELFRelocationTypeName(uint32_t Machine,
24 uint32_t Type) {
25 switch (Machine) {
26 case ELF::EM_X86_64:
27 switch (Type) {
28#include "llvm/BinaryFormat/ELFRelocs/x86_64.def"
29 default:
30 break;
31 }
32 break;
33 case ELF::EM_386:
34 case ELF::EM_IAMCU:
35 switch (Type) {
36#include "llvm/BinaryFormat/ELFRelocs/i386.def"
37 default:
38 break;
39 }
40 break;
41 case ELF::EM_MIPS:
42 switch (Type) {
43#include "llvm/BinaryFormat/ELFRelocs/Mips.def"
44 default:
45 break;
46 }
47 break;
48 case ELF::EM_AARCH64:
49 switch (Type) {
50#include "llvm/BinaryFormat/ELFRelocs/AArch64.def"
51 default:
52 break;
53 }
54 break;
55 case ELF::EM_ARM:
56 switch (Type) {
57#include "llvm/BinaryFormat/ELFRelocs/ARM.def"
58 default:
59 break;
60 }
61 break;
62 case ELF::EM_ARC_COMPACT:
63 case ELF::EM_ARC_COMPACT2:
64 switch (Type) {
65#include "llvm/BinaryFormat/ELFRelocs/ARC.def"
66 default:
67 break;
68 }
69 break;
70 case ELF::EM_AVR:
71 switch (Type) {
72#include "llvm/BinaryFormat/ELFRelocs/AVR.def"
73 default:
74 break;
75 }
76 break;
77 case ELF::EM_HEXAGON:
78 switch (Type) {
79#include "llvm/BinaryFormat/ELFRelocs/Hexagon.def"
80 default:
81 break;
82 }
83 break;
84 case ELF::EM_LANAI:
85 switch (Type) {
86#include "llvm/BinaryFormat/ELFRelocs/Lanai.def"
87 default:
88 break;
89 }
90 break;
91 case ELF::EM_PPC:
92 switch (Type) {
93#include "llvm/BinaryFormat/ELFRelocs/PowerPC.def"
94 default:
95 break;
96 }
97 break;
98 case ELF::EM_PPC64:
99 switch (Type) {
100#include "llvm/BinaryFormat/ELFRelocs/PowerPC64.def"
101 default:
102 break;
103 }
104 break;
105 case ELF::EM_RISCV:
106 switch (Type) {
107#include "llvm/BinaryFormat/ELFRelocs/RISCV.def"
108 default:
109 break;
110 }
111 break;
112 case ELF::EM_S390:
113 switch (Type) {
114#include "llvm/BinaryFormat/ELFRelocs/SystemZ.def"
115 default:
116 break;
117 }
118 break;
119 case ELF::EM_SPARC:
120 case ELF::EM_SPARC32PLUS:
121 case ELF::EM_SPARCV9:
122 switch (Type) {
123#include "llvm/BinaryFormat/ELFRelocs/Sparc.def"
124 default:
125 break;
126 }
127 break;
128 case ELF::EM_AMDGPU:
129 switch (Type) {
130#include "llvm/BinaryFormat/ELFRelocs/AMDGPU.def"
131 default:
132 break;
133 }
134 break;
135 case ELF::EM_BPF:
136 switch (Type) {
137#include "llvm/BinaryFormat/ELFRelocs/BPF.def"
138 default:
139 break;
140 }
141 break;
142 case ELF::EM_MSP430:
143 switch (Type) {
144#include "llvm/BinaryFormat/ELFRelocs/MSP430.def"
145 default:
146 break;
147 }
148 break;
149 default:
150 break;
151 }
152 return "Unknown";
153}
154
155#undef ELF_RELOC
156
157uint32_t llvm::object::getELFRelativeRelocationType(uint32_t Machine) {
158 switch (Machine) {
159 case ELF::EM_X86_64:
160 return ELF::R_X86_64_RELATIVE;
161 case ELF::EM_386:
162 case ELF::EM_IAMCU:
163 return ELF::R_386_RELATIVE;
164 case ELF::EM_MIPS:
165 break;
166 case ELF::EM_AARCH64:
167 return ELF::R_AARCH64_RELATIVE;
168 case ELF::EM_ARM:
169 return ELF::R_ARM_RELATIVE;
170 case ELF::EM_ARC_COMPACT:
171 case ELF::EM_ARC_COMPACT2:
172 return ELF::R_ARC_RELATIVE;
173 case ELF::EM_AVR:
174 break;
175 case ELF::EM_HEXAGON:
176 return ELF::R_HEX_RELATIVE;
177 case ELF::EM_LANAI:
178 break;
179 case ELF::EM_PPC:
180 break;
181 case ELF::EM_PPC64:
182 return ELF::R_PPC64_RELATIVE;
183 case ELF::EM_RISCV:
184 return ELF::R_RISCV_RELATIVE;
185 case ELF::EM_S390:
186 return ELF::R_390_RELATIVE;
187 case ELF::EM_SPARC:
188 case ELF::EM_SPARC32PLUS:
189 case ELF::EM_SPARCV9:
190 return ELF::R_SPARC_RELATIVE;
191 case ELF::EM_AMDGPU:
192 break;
193 case ELF::EM_BPF:
194 break;
195 default:
196 break;
197 }
198 return 0;
199}
200
201StringRef llvm::object::getELFSectionTypeName(uint32_t Machine, unsigned Type) {
202 switch (Machine) {
203 case ELF::EM_ARM:
204 switch (Type) {
205 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_EXIDX)case ELF::SHT_ARM_EXIDX: return "SHT_ARM_EXIDX";;
206 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_PREEMPTMAP)case ELF::SHT_ARM_PREEMPTMAP: return "SHT_ARM_PREEMPTMAP";;
207 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_ATTRIBUTES)case ELF::SHT_ARM_ATTRIBUTES: return "SHT_ARM_ATTRIBUTES";;
208 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_DEBUGOVERLAY)case ELF::SHT_ARM_DEBUGOVERLAY: return "SHT_ARM_DEBUGOVERLAY"
;
;
209 STRINGIFY_ENUM_CASE(ELF, SHT_ARM_OVERLAYSECTION)case ELF::SHT_ARM_OVERLAYSECTION: return "SHT_ARM_OVERLAYSECTION"
;
;
210 }
211 break;
212 case ELF::EM_HEXAGON:
213 switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_HEX_ORDERED)case ELF::SHT_HEX_ORDERED: return "SHT_HEX_ORDERED";; }
214 break;
215 case ELF::EM_X86_64:
216 switch (Type) { STRINGIFY_ENUM_CASE(ELF, SHT_X86_64_UNWIND)case ELF::SHT_X86_64_UNWIND: return "SHT_X86_64_UNWIND";; }
217 break;
218 case ELF::EM_MIPS:
219 case ELF::EM_MIPS_RS3_LE:
220 switch (Type) {
221 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_REGINFO)case ELF::SHT_MIPS_REGINFO: return "SHT_MIPS_REGINFO";;
222 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_OPTIONS)case ELF::SHT_MIPS_OPTIONS: return "SHT_MIPS_OPTIONS";;
223 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_ABIFLAGS)case ELF::SHT_MIPS_ABIFLAGS: return "SHT_MIPS_ABIFLAGS";;
224 STRINGIFY_ENUM_CASE(ELF, SHT_MIPS_DWARF)case ELF::SHT_MIPS_DWARF: return "SHT_MIPS_DWARF";;
225 }
226 break;
227 default:
228 break;
229 }
230
231 switch (Type) {
232 STRINGIFY_ENUM_CASE(ELF, SHT_NULL)case ELF::SHT_NULL: return "SHT_NULL";;
233 STRINGIFY_ENUM_CASE(ELF, SHT_PROGBITS)case ELF::SHT_PROGBITS: return "SHT_PROGBITS";;
234 STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB)case ELF::SHT_SYMTAB: return "SHT_SYMTAB";;
235 STRINGIFY_ENUM_CASE(ELF, SHT_STRTAB)case ELF::SHT_STRTAB: return "SHT_STRTAB";;
236 STRINGIFY_ENUM_CASE(ELF, SHT_RELA)case ELF::SHT_RELA: return "SHT_RELA";;
237 STRINGIFY_ENUM_CASE(ELF, SHT_HASH)case ELF::SHT_HASH: return "SHT_HASH";;
238 STRINGIFY_ENUM_CASE(ELF, SHT_DYNAMIC)case ELF::SHT_DYNAMIC: return "SHT_DYNAMIC";;
239 STRINGIFY_ENUM_CASE(ELF, SHT_NOTE)case ELF::SHT_NOTE: return "SHT_NOTE";;
240 STRINGIFY_ENUM_CASE(ELF, SHT_NOBITS)case ELF::SHT_NOBITS: return "SHT_NOBITS";;
241 STRINGIFY_ENUM_CASE(ELF, SHT_REL)case ELF::SHT_REL: return "SHT_REL";;
242 STRINGIFY_ENUM_CASE(ELF, SHT_SHLIB)case ELF::SHT_SHLIB: return "SHT_SHLIB";;
243 STRINGIFY_ENUM_CASE(ELF, SHT_DYNSYM)case ELF::SHT_DYNSYM: return "SHT_DYNSYM";;
244 STRINGIFY_ENUM_CASE(ELF, SHT_INIT_ARRAY)case ELF::SHT_INIT_ARRAY: return "SHT_INIT_ARRAY";;
245 STRINGIFY_ENUM_CASE(ELF, SHT_FINI_ARRAY)case ELF::SHT_FINI_ARRAY: return "SHT_FINI_ARRAY";;
246 STRINGIFY_ENUM_CASE(ELF, SHT_PREINIT_ARRAY)case ELF::SHT_PREINIT_ARRAY: return "SHT_PREINIT_ARRAY";;
247 STRINGIFY_ENUM_CASE(ELF, SHT_GROUP)case ELF::SHT_GROUP: return "SHT_GROUP";;
248 STRINGIFY_ENUM_CASE(ELF, SHT_SYMTAB_SHNDX)case ELF::SHT_SYMTAB_SHNDX: return "SHT_SYMTAB_SHNDX";;
249 STRINGIFY_ENUM_CASE(ELF, SHT_RELR)case ELF::SHT_RELR: return "SHT_RELR";;
250 STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_REL)case ELF::SHT_ANDROID_REL: return "SHT_ANDROID_REL";;
251 STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELA)case ELF::SHT_ANDROID_RELA: return "SHT_ANDROID_RELA";;
252 STRINGIFY_ENUM_CASE(ELF, SHT_ANDROID_RELR)case ELF::SHT_ANDROID_RELR: return "SHT_ANDROID_RELR";;
253 STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ODRTAB)case ELF::SHT_LLVM_ODRTAB: return "SHT_LLVM_ODRTAB";;
254 STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_LINKER_OPTIONS)case ELF::SHT_LLVM_LINKER_OPTIONS: return "SHT_LLVM_LINKER_OPTIONS"
;
;
255 STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_CALL_GRAPH_PROFILE)case ELF::SHT_LLVM_CALL_GRAPH_PROFILE: return "SHT_LLVM_CALL_GRAPH_PROFILE"
;
;
256 STRINGIFY_ENUM_CASE(ELF, SHT_LLVM_ADDRSIG)case ELF::SHT_LLVM_ADDRSIG: return "SHT_LLVM_ADDRSIG";;
257 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_ATTRIBUTES)case ELF::SHT_GNU_ATTRIBUTES: return "SHT_GNU_ATTRIBUTES";;
258 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_HASH)case ELF::SHT_GNU_HASH: return "SHT_GNU_HASH";;
259 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verdef)case ELF::SHT_GNU_verdef: return "SHT_GNU_verdef";;
260 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_verneed)case ELF::SHT_GNU_verneed: return "SHT_GNU_verneed";;
261 STRINGIFY_ENUM_CASE(ELF, SHT_GNU_versym)case ELF::SHT_GNU_versym: return "SHT_GNU_versym";;
262 default:
263 return "Unknown";
264 }
265}
266
267template <class ELFT>
268Expected<std::vector<typename ELFT::Rela>>
269ELFFile<ELFT>::decode_relrs(Elf_Relr_Range relrs) const {
270 // This function decodes the contents of an SHT_RELR packed relocation
271 // section.
272 //
273 // Proposal for adding SHT_RELR sections to generic-abi is here:
274 // https://groups.google.com/forum/#!topic/generic-abi/bX460iggiKg
275 //
276 // The encoded sequence of Elf64_Relr entries in a SHT_RELR section looks
277 // like [ AAAAAAAA BBBBBBB1 BBBBBBB1 ... AAAAAAAA BBBBBB1 ... ]
278 //
279 // i.e. start with an address, followed by any number of bitmaps. The address
280 // entry encodes 1 relocation. The subsequent bitmap entries encode up to 63
281 // relocations each, at subsequent offsets following the last address entry.
282 //
283 // The bitmap entries must have 1 in the least significant bit. The assumption
284 // here is that an address cannot have 1 in lsb. Odd addresses are not
285 // supported.
286 //
287 // Excluding the least significant bit in the bitmap, each non-zero bit in
288 // the bitmap represents a relocation to be applied to a corresponding machine
289 // word that follows the base address word. The second least significant bit
290 // represents the machine word immediately following the initial address, and
291 // each bit that follows represents the next word, in linear order. As such,
292 // a single bitmap can encode up to 31 relocations in a 32-bit object, and
293 // 63 relocations in a 64-bit object.
294 //
295 // This encoding has a couple of interesting properties:
296 // 1. Looking at any entry, it is clear whether it's an address or a bitmap:
297 // even means address, odd means bitmap.
298 // 2. Just a simple list of addresses is a valid encoding.
299
300 Elf_Rela Rela;
301 Rela.r_info = 0;
302 Rela.r_addend = 0;
303 Rela.setType(getRelativeRelocationType(), false);
304 std::vector<Elf_Rela> Relocs;
305
306 // Word type: uint32_t for Elf32, and uint64_t for Elf64.
307 typedef typename ELFT::uint Word;
308
309 // Word size in number of bytes.
310 const size_t WordSize = sizeof(Word);
311
312 // Number of bits used for the relocation offsets bitmap.
313 // These many relative relocations can be encoded in a single entry.
314 const size_t NBits = 8*WordSize - 1;
315
316 Word Base = 0;
317 for (const Elf_Relr &R : relrs) {
318 Word Entry = R;
319 if ((Entry&1) == 0) {
320 // Even entry: encodes the offset for next relocation.
321 Rela.r_offset = Entry;
322 Relocs.push_back(Rela);
323 // Set base offset for subsequent bitmap entries.
324 Base = Entry + WordSize;
325 continue;
326 }
327
328 // Odd entry: encodes bitmap for relocations starting at base.
329 Word Offset = Base;
330 while (Entry != 0) {
331 Entry >>= 1;
332 if ((Entry&1) != 0) {
333 Rela.r_offset = Offset;
334 Relocs.push_back(Rela);
335 }
336 Offset += WordSize;
337 }
338
339 // Advance base offset by NBits words.
340 Base += NBits * WordSize;
341 }
342
343 return Relocs;
344}
345
346template <class ELFT>
347Expected<std::vector<typename ELFT::Rela>>
348ELFFile<ELFT>::android_relas(const Elf_Shdr *Sec) const {
349 // This function reads relocations in Android's packed relocation format,
350 // which is based on SLEB128 and delta encoding.
351 Expected<ArrayRef<uint8_t>> ContentsOrErr = getSectionContents(Sec);
1
Calling 'ELFFile::getSectionContents'
352 if (!ContentsOrErr)
353 return ContentsOrErr.takeError();
354 const uint8_t *Cur = ContentsOrErr->begin();
355 const uint8_t *End = ContentsOrErr->end();
356 if (ContentsOrErr->size() < 4 || Cur[0] != 'A' || Cur[1] != 'P' ||
357 Cur[2] != 'S' || Cur[3] != '2')
358 return createError("invalid packed relocation header");
359 Cur += 4;
360
361 const char *ErrStr = nullptr;
362 auto ReadSLEB = [&]() -> int64_t {
363 if (ErrStr)
364 return 0;
365 unsigned Len;
366 int64_t Result = decodeSLEB128(Cur, &Len, End, &ErrStr);
367 Cur += Len;
368 return Result;
369 };
370
371 uint64_t NumRelocs = ReadSLEB();
372 uint64_t Offset = ReadSLEB();
373 uint64_t Addend = 0;
374
375 if (ErrStr)
376 return createError(ErrStr);
377
378 std::vector<Elf_Rela> Relocs;
379 Relocs.reserve(NumRelocs);
380 while (NumRelocs) {
381 uint64_t NumRelocsInGroup = ReadSLEB();
382 if (NumRelocsInGroup > NumRelocs)
383 return createError("relocation group unexpectedly large");
384 NumRelocs -= NumRelocsInGroup;
385
386 uint64_t GroupFlags = ReadSLEB();
387 bool GroupedByInfo = GroupFlags & ELF::RELOCATION_GROUPED_BY_INFO_FLAG;
388 bool GroupedByOffsetDelta = GroupFlags & ELF::RELOCATION_GROUPED_BY_OFFSET_DELTA_FLAG;
389 bool GroupedByAddend = GroupFlags & ELF::RELOCATION_GROUPED_BY_ADDEND_FLAG;
390 bool GroupHasAddend = GroupFlags & ELF::RELOCATION_GROUP_HAS_ADDEND_FLAG;
391
392 uint64_t GroupOffsetDelta;
393 if (GroupedByOffsetDelta)
394 GroupOffsetDelta = ReadSLEB();
395
396 uint64_t GroupRInfo;
397 if (GroupedByInfo)
398 GroupRInfo = ReadSLEB();
399
400 if (GroupedByAddend && GroupHasAddend)
401 Addend += ReadSLEB();
402
403 if (!GroupHasAddend)
404 Addend = 0;
405
406 for (uint64_t I = 0; I != NumRelocsInGroup; ++I) {
407 Elf_Rela R;
408 Offset += GroupedByOffsetDelta ? GroupOffsetDelta : ReadSLEB();
409 R.r_offset = Offset;
410 R.r_info = GroupedByInfo ? GroupRInfo : ReadSLEB();
411 if (GroupHasAddend && !GroupedByAddend)
412 Addend += ReadSLEB();
413 R.r_addend = Addend;
414 Relocs.push_back(R);
415
416 if (ErrStr)
417 return createError(ErrStr);
418 }
419
420 if (ErrStr)
421 return createError(ErrStr);
422 }
423
424 return Relocs;
425}
426
427template <class ELFT>
428const char *ELFFile<ELFT>::getDynamicTagAsString(unsigned Arch,
429 uint64_t Type) const {
430#define DYNAMIC_STRINGIFY_ENUM(tag, value) \
431 case value: \
432 return #tag;
433
434#define DYNAMIC_TAG(n, v)
435 switch (Arch) {
436 case ELF::EM_HEXAGON:
437 switch (Type) {
438#define HEXAGON_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
439#include "llvm/BinaryFormat/DynamicTags.def"
440#undef HEXAGON_DYNAMIC_TAG
441 }
442
443 case ELF::EM_MIPS:
444 switch (Type) {
445#define MIPS_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
446#include "llvm/BinaryFormat/DynamicTags.def"
447#undef MIPS_DYNAMIC_TAG
448 }
449
450 case ELF::EM_PPC64:
451 switch (Type) {
452#define PPC64_DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
453#include "llvm/BinaryFormat/DynamicTags.def"
454#undef PPC64_DYNAMIC_TAG
455 }
456 }
457#undef DYNAMIC_TAG
458 switch (Type) {
459// Now handle all dynamic tags except the architecture specific ones
460#define MIPS_DYNAMIC_TAG(name, value)
461#define HEXAGON_DYNAMIC_TAG(name, value)
462#define PPC64_DYNAMIC_TAG(name, value)
463// Also ignore marker tags such as DT_HIOS (maps to DT_VERNEEDNUM), etc.
464#define DYNAMIC_TAG_MARKER(name, value)
465#define DYNAMIC_TAG(name, value) DYNAMIC_STRINGIFY_ENUM(name, value)
466#include "llvm/BinaryFormat/DynamicTags.def"
467#undef DYNAMIC_TAG
468#undef MIPS_DYNAMIC_TAG
469#undef HEXAGON_DYNAMIC_TAG
470#undef PPC64_DYNAMIC_TAG
471#undef DYNAMIC_TAG_MARKER
472#undef DYNAMIC_STRINGIFY_ENUM
473 default:
474 return "unknown";
475 }
476}
477
478template <class ELFT>
479const char *ELFFile<ELFT>::getDynamicTagAsString(uint64_t Type) const {
480 return getDynamicTagAsString(getHeader()->e_machine, Type);
481}
482
483template <class ELFT>
484Expected<typename ELFT::DynRange> ELFFile<ELFT>::dynamicEntries() const {
485 ArrayRef<Elf_Dyn> Dyn;
486 size_t DynSecSize = 0;
487
488 auto ProgramHeadersOrError = program_headers();
489 if (!ProgramHeadersOrError)
490 return ProgramHeadersOrError.takeError();
491
492 for (const Elf_Phdr &Phdr : *ProgramHeadersOrError) {
493 if (Phdr.p_type == ELF::PT_DYNAMIC) {
494 Dyn = makeArrayRef(
495 reinterpret_cast<const Elf_Dyn *>(base() + Phdr.p_offset),
496 Phdr.p_filesz / sizeof(Elf_Dyn));
497 DynSecSize = Phdr.p_filesz;
498 break;
499 }
500 }
501
502 // If we can't find the dynamic section in the program headers, we just fall
503 // back on the sections.
504 if (Dyn.empty()) {
505 auto SectionsOrError = sections();
506 if (!SectionsOrError)
507 return SectionsOrError.takeError();
508
509 for (const Elf_Shdr &Sec : *SectionsOrError) {
510 if (Sec.sh_type == ELF::SHT_DYNAMIC) {
511 Expected<ArrayRef<Elf_Dyn>> DynOrError =
512 getSectionContentsAsArray<Elf_Dyn>(&Sec);
513 if (!DynOrError)
514 return DynOrError.takeError();
515 Dyn = *DynOrError;
516 DynSecSize = Sec.sh_size;
517 break;
518 }
519 }
520
521 if (!Dyn.data())
522 return ArrayRef<Elf_Dyn>();
523 }
524
525 if (Dyn.empty())
526 return createError("invalid empty dynamic section");
527
528 if (DynSecSize % sizeof(Elf_Dyn) != 0)
529 return createError("malformed dynamic section");
530
531 if (Dyn.back().d_tag != ELF::DT_NULL)
532 return createError("dynamic sections must be DT_NULL terminated");
533
534 return Dyn;
535}
536
537template <class ELFT>
538Expected<const uint8_t *> ELFFile<ELFT>::toMappedAddr(uint64_t VAddr) const {
539 auto ProgramHeadersOrError = program_headers();
540 if (!ProgramHeadersOrError)
541 return ProgramHeadersOrError.takeError();
542
543 llvm::SmallVector<Elf_Phdr *, 4> LoadSegments;
544
545 for (const Elf_Phdr &Phdr : *ProgramHeadersOrError)
546 if (Phdr.p_type == ELF::PT_LOAD)
547 LoadSegments.push_back(const_cast<Elf_Phdr *>(&Phdr));
548
549 const Elf_Phdr *const *I =
550 std::upper_bound(LoadSegments.begin(), LoadSegments.end(), VAddr,
551 [](uint64_t VAddr, const Elf_Phdr_Impl<ELFT> *Phdr) {
552 return VAddr < Phdr->p_vaddr;
553 });
554
555 if (I == LoadSegments.begin())
556 return createError("Virtual address is not in any segment");
557 --I;
558 const Elf_Phdr &Phdr = **I;
559 uint64_t Delta = VAddr - Phdr.p_vaddr;
560 if (Delta >= Phdr.p_filesz)
561 return createError("Virtual address is not in any segment");
562 return base() + Phdr.p_offset + Delta;
563}
564
565template class llvm::object::ELFFile<ELF32LE>;
566template class llvm::object::ELFFile<ELF32BE>;
567template class llvm::object::ELFFile<ELF64LE>;
568template class llvm::object::ELFFile<ELF64BE>;

/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Object/ELF.h

1//===- ELF.h - ELF object file implementation -------------------*- C++ -*-===//
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 file declares the ELFFile template class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_OBJECT_ELF_H
15#define LLVM_OBJECT_ELF_H
16
17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/StringRef.h"
20#include "llvm/BinaryFormat/ELF.h"
21#include "llvm/Object/ELFTypes.h"
22#include "llvm/Object/Error.h"
23#include "llvm/Support/Endian.h"
24#include "llvm/Support/Error.h"
25#include <cassert>
26#include <cstddef>
27#include <cstdint>
28#include <limits>
29#include <utility>
30
31namespace llvm {
32namespace object {
33
34StringRef getELFRelocationTypeName(uint32_t Machine, uint32_t Type);
35uint32_t getELFRelativeRelocationType(uint32_t Machine);
36StringRef getELFSectionTypeName(uint32_t Machine, uint32_t Type);
37
38// Subclasses of ELFFile may need this for template instantiation
39inline std::pair<unsigned char, unsigned char>
40getElfArchType(StringRef Object) {
41 if (Object.size() < ELF::EI_NIDENT)
42 return std::make_pair((uint8_t)ELF::ELFCLASSNONE,
43 (uint8_t)ELF::ELFDATANONE);
44 return std::make_pair((uint8_t)Object[ELF::EI_CLASS],
45 (uint8_t)Object[ELF::EI_DATA]);
46}
47
48static inline Error createError(StringRef Err) {
49 return make_error<StringError>(Err, object_error::parse_failed);
7
Calling 'make_error<llvm::StringError, llvm::StringRef &, llvm::object::object_error>'
50}
51
52template <class ELFT>
53class ELFFile {
54public:
55 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)using Elf_Addr = typename ELFT::Addr; using Elf_Off = typename
ELFT::Off; using Elf_Half = typename ELFT::Half; using Elf_Word
= typename ELFT::Word; using Elf_Sword = typename ELFT::Sword
; using Elf_Xword = typename ELFT::Xword; using Elf_Sxword = typename
ELFT::Sxword;
56 using uintX_t = typename ELFT::uint;
57 using Elf_Ehdr = typename ELFT::Ehdr;
58 using Elf_Shdr = typename ELFT::Shdr;
59 using Elf_Sym = typename ELFT::Sym;
60 using Elf_Dyn = typename ELFT::Dyn;
61 using Elf_Phdr = typename ELFT::Phdr;
62 using Elf_Rel = typename ELFT::Rel;
63 using Elf_Rela = typename ELFT::Rela;
64 using Elf_Relr = typename ELFT::Relr;
65 using Elf_Verdef = typename ELFT::Verdef;
66 using Elf_Verdaux = typename ELFT::Verdaux;
67 using Elf_Verneed = typename ELFT::Verneed;
68 using Elf_Vernaux = typename ELFT::Vernaux;
69 using Elf_Versym = typename ELFT::Versym;
70 using Elf_Hash = typename ELFT::Hash;
71 using Elf_GnuHash = typename ELFT::GnuHash;
72 using Elf_Nhdr = typename ELFT::Nhdr;
73 using Elf_Note = typename ELFT::Note;
74 using Elf_Note_Iterator = typename ELFT::NoteIterator;
75 using Elf_Dyn_Range = typename ELFT::DynRange;
76 using Elf_Shdr_Range = typename ELFT::ShdrRange;
77 using Elf_Sym_Range = typename ELFT::SymRange;
78 using Elf_Rel_Range = typename ELFT::RelRange;
79 using Elf_Rela_Range = typename ELFT::RelaRange;
80 using Elf_Relr_Range = typename ELFT::RelrRange;
81 using Elf_Phdr_Range = typename ELFT::PhdrRange;
82
83 const uint8_t *base() const {
84 return reinterpret_cast<const uint8_t *>(Buf.data());
85 }
86
87 size_t getBufSize() const { return Buf.size(); }
88
89private:
90 StringRef Buf;
91
92 ELFFile(StringRef Object);
93
94public:
95 const Elf_Ehdr *getHeader() const {
96 return reinterpret_cast<const Elf_Ehdr *>(base());
97 }
98
99 template <typename T>
100 Expected<const T *> getEntry(uint32_t Section, uint32_t Entry) const;
101 template <typename T>
102 Expected<const T *> getEntry(const Elf_Shdr *Section, uint32_t Entry) const;
103
104 Expected<StringRef> getStringTable(const Elf_Shdr *Section) const;
105 Expected<StringRef> getStringTableForSymtab(const Elf_Shdr &Section) const;
106 Expected<StringRef> getStringTableForSymtab(const Elf_Shdr &Section,
107 Elf_Shdr_Range Sections) const;
108
109 Expected<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section) const;
110 Expected<ArrayRef<Elf_Word>> getSHNDXTable(const Elf_Shdr &Section,
111 Elf_Shdr_Range Sections) const;
112
113 StringRef getRelocationTypeName(uint32_t Type) const;
114 void getRelocationTypeName(uint32_t Type,
115 SmallVectorImpl<char> &Result) const;
116 uint32_t getRelativeRelocationType() const;
117
118 const char *getDynamicTagAsString(unsigned Arch, uint64_t Type) const;
119 const char *getDynamicTagAsString(uint64_t Type) const;
120
121 /// Get the symbol for a given relocation.
122 Expected<const Elf_Sym *> getRelocationSymbol(const Elf_Rel *Rel,
123 const Elf_Shdr *SymTab) const;
124
125 static Expected<ELFFile> create(StringRef Object);
126
127 bool isMipsELF64() const {
128 return getHeader()->e_machine == ELF::EM_MIPS &&
129 getHeader()->getFileClass() == ELF::ELFCLASS64;
130 }
131
132 bool isMips64EL() const {
133 return isMipsELF64() &&
134 getHeader()->getDataEncoding() == ELF::ELFDATA2LSB;
135 }
136
137 Expected<Elf_Shdr_Range> sections() const;
138
139 Expected<Elf_Dyn_Range> dynamicEntries() const;
140
141 Expected<const uint8_t *> toMappedAddr(uint64_t VAddr) const;
142
143 Expected<Elf_Sym_Range> symbols(const Elf_Shdr *Sec) const {
144 if (!Sec)
145 return makeArrayRef<Elf_Sym>(nullptr, nullptr);
146 return getSectionContentsAsArray<Elf_Sym>(Sec);
147 }
148
149 Expected<Elf_Rela_Range> relas(const Elf_Shdr *Sec) const {
150 return getSectionContentsAsArray<Elf_Rela>(Sec);
151 }
152
153 Expected<Elf_Rel_Range> rels(const Elf_Shdr *Sec) const {
154 return getSectionContentsAsArray<Elf_Rel>(Sec);
155 }
156
157 Expected<Elf_Relr_Range> relrs(const Elf_Shdr *Sec) const {
158 return getSectionContentsAsArray<Elf_Relr>(Sec);
159 }
160
161 Expected<std::vector<Elf_Rela>> decode_relrs(Elf_Relr_Range relrs) const;
162
163 Expected<std::vector<Elf_Rela>> android_relas(const Elf_Shdr *Sec) const;
164
165 /// Iterate over program header table.
166 Expected<Elf_Phdr_Range> program_headers() const {
167 if (getHeader()->e_phnum && getHeader()->e_phentsize != sizeof(Elf_Phdr))
168 return createError("invalid e_phentsize");
169 if (getHeader()->e_phoff +
170 (getHeader()->e_phnum * getHeader()->e_phentsize) >
171 getBufSize())
172 return createError("program headers longer than binary");
173 auto *Begin =
174 reinterpret_cast<const Elf_Phdr *>(base() + getHeader()->e_phoff);
175 return makeArrayRef(Begin, Begin + getHeader()->e_phnum);
176 }
177
178 /// Get an iterator over notes in a program header.
179 ///
180 /// The program header must be of type \c PT_NOTE.
181 ///
182 /// \param Phdr the program header to iterate over.
183 /// \param Err [out] an error to support fallible iteration, which should
184 /// be checked after iteration ends.
185 Elf_Note_Iterator notes_begin(const Elf_Phdr &Phdr, Error &Err) const {
186 if (Phdr.p_type != ELF::PT_NOTE) {
187 Err = createError("attempt to iterate notes of non-note program header");
188 return Elf_Note_Iterator(Err);
189 }
190 if (Phdr.p_offset + Phdr.p_filesz > getBufSize()) {
191 Err = createError("invalid program header offset/size");
192 return Elf_Note_Iterator(Err);
193 }
194 return Elf_Note_Iterator(base() + Phdr.p_offset, Phdr.p_filesz, Err);
195 }
196
197 /// Get an iterator over notes in a section.
198 ///
199 /// The section must be of type \c SHT_NOTE.
200 ///
201 /// \param Shdr the section to iterate over.
202 /// \param Err [out] an error to support fallible iteration, which should
203 /// be checked after iteration ends.
204 Elf_Note_Iterator notes_begin(const Elf_Shdr &Shdr, Error &Err) const {
205 if (Shdr.sh_type != ELF::SHT_NOTE) {
206 Err = createError("attempt to iterate notes of non-note section");
207 return Elf_Note_Iterator(Err);
208 }
209 if (Shdr.sh_offset + Shdr.sh_size > getBufSize()) {
210 Err = createError("invalid section offset/size");
211 return Elf_Note_Iterator(Err);
212 }
213 return Elf_Note_Iterator(base() + Shdr.sh_offset, Shdr.sh_size, Err);
214 }
215
216 /// Get the end iterator for notes.
217 Elf_Note_Iterator notes_end() const {
218 return Elf_Note_Iterator();
219 }
220
221 /// Get an iterator range over notes of a program header.
222 ///
223 /// The program header must be of type \c PT_NOTE.
224 ///
225 /// \param Phdr the program header to iterate over.
226 /// \param Err [out] an error to support fallible iteration, which should
227 /// be checked after iteration ends.
228 iterator_range<Elf_Note_Iterator> notes(const Elf_Phdr &Phdr,
229 Error &Err) const {
230 return make_range(notes_begin(Phdr, Err), notes_end());
231 }
232
233 /// Get an iterator range over notes of a section.
234 ///
235 /// The section must be of type \c SHT_NOTE.
236 ///
237 /// \param Shdr the section to iterate over.
238 /// \param Err [out] an error to support fallible iteration, which should
239 /// be checked after iteration ends.
240 iterator_range<Elf_Note_Iterator> notes(const Elf_Shdr &Shdr,
241 Error &Err) const {
242 return make_range(notes_begin(Shdr, Err), notes_end());
243 }
244
245 Expected<StringRef> getSectionStringTable(Elf_Shdr_Range Sections) const;
246 Expected<uint32_t> getSectionIndex(const Elf_Sym *Sym, Elf_Sym_Range Syms,
247 ArrayRef<Elf_Word> ShndxTable) const;
248 Expected<const Elf_Shdr *> getSection(const Elf_Sym *Sym,
249 const Elf_Shdr *SymTab,
250 ArrayRef<Elf_Word> ShndxTable) const;
251 Expected<const Elf_Shdr *> getSection(const Elf_Sym *Sym,
252 Elf_Sym_Range Symtab,
253 ArrayRef<Elf_Word> ShndxTable) const;
254 Expected<const Elf_Shdr *> getSection(uint32_t Index) const;
255 Expected<const Elf_Shdr *> getSection(const StringRef SectionName) const;
256
257 Expected<const Elf_Sym *> getSymbol(const Elf_Shdr *Sec,
258 uint32_t Index) const;
259
260 Expected<StringRef> getSectionName(const Elf_Shdr *Section) const;
261 Expected<StringRef> getSectionName(const Elf_Shdr *Section,
262 StringRef DotShstrtab) const;
263 template <typename T>
264 Expected<ArrayRef<T>> getSectionContentsAsArray(const Elf_Shdr *Sec) const;
265 Expected<ArrayRef<uint8_t>> getSectionContents(const Elf_Shdr *Sec) const;
266};
267
268using ELF32LEFile = ELFFile<ELF32LE>;
269using ELF64LEFile = ELFFile<ELF64LE>;
270using ELF32BEFile = ELFFile<ELF32BE>;
271using ELF64BEFile = ELFFile<ELF64BE>;
272
273template <class ELFT>
274inline Expected<const typename ELFT::Shdr *>
275getSection(typename ELFT::ShdrRange Sections, uint32_t Index) {
276 if (Index >= Sections.size())
277 return createError("invalid section index");
278 return &Sections[Index];
279}
280
281template <class ELFT>
282inline Expected<uint32_t>
283getExtendedSymbolTableIndex(const typename ELFT::Sym *Sym,
284 const typename ELFT::Sym *FirstSym,
285 ArrayRef<typename ELFT::Word> ShndxTable) {
286 assert(Sym->st_shndx == ELF::SHN_XINDEX)((Sym->st_shndx == ELF::SHN_XINDEX) ? static_cast<void>
(0) : __assert_fail ("Sym->st_shndx == ELF::SHN_XINDEX", "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Object/ELF.h"
, 286, __PRETTY_FUNCTION__))
;
287 unsigned Index = Sym - FirstSym;
288 if (Index >= ShndxTable.size())
289 return createError("index past the end of the symbol table");
290
291 // The size of the table was checked in getSHNDXTable.
292 return ShndxTable[Index];
293}
294
295template <class ELFT>
296Expected<uint32_t>
297ELFFile<ELFT>::getSectionIndex(const Elf_Sym *Sym, Elf_Sym_Range Syms,
298 ArrayRef<Elf_Word> ShndxTable) const {
299 uint32_t Index = Sym->st_shndx;
300 if (Index == ELF::SHN_XINDEX) {
301 auto ErrorOrIndex = getExtendedSymbolTableIndex<ELFT>(
302 Sym, Syms.begin(), ShndxTable);
303 if (!ErrorOrIndex)
304 return ErrorOrIndex.takeError();
305 return *ErrorOrIndex;
306 }
307 if (Index == ELF::SHN_UNDEF || Index >= ELF::SHN_LORESERVE)
308 return 0;
309 return Index;
310}
311
312template <class ELFT>
313Expected<const typename ELFT::Shdr *>
314ELFFile<ELFT>::getSection(const Elf_Sym *Sym, const Elf_Shdr *SymTab,
315 ArrayRef<Elf_Word> ShndxTable) const {
316 auto SymsOrErr = symbols(SymTab);
317 if (!SymsOrErr)
318 return SymsOrErr.takeError();
319 return getSection(Sym, *SymsOrErr, ShndxTable);
320}
321
322template <class ELFT>
323Expected<const typename ELFT::Shdr *>
324ELFFile<ELFT>::getSection(const Elf_Sym *Sym, Elf_Sym_Range Symbols,
325 ArrayRef<Elf_Word> ShndxTable) const {
326 auto IndexOrErr = getSectionIndex(Sym, Symbols, ShndxTable);
327 if (!IndexOrErr)
328 return IndexOrErr.takeError();
329 uint32_t Index = *IndexOrErr;
330 if (Index == 0)
331 return nullptr;
332 return getSection(Index);
333}
334
335template <class ELFT>
336inline Expected<const typename ELFT::Sym *>
337getSymbol(typename ELFT::SymRange Symbols, uint32_t Index) {
338 if (Index >= Symbols.size())
339 return createError("invalid symbol index");
340 return &Symbols[Index];
341}
342
343template <class ELFT>
344Expected<const typename ELFT::Sym *>
345ELFFile<ELFT>::getSymbol(const Elf_Shdr *Sec, uint32_t Index) const {
346 auto SymtabOrErr = symbols(Sec);
347 if (!SymtabOrErr)
348 return SymtabOrErr.takeError();
349 return object::getSymbol<ELFT>(*SymtabOrErr, Index);
350}
351
352template <class ELFT>
353template <typename T>
354Expected<ArrayRef<T>>
355ELFFile<ELFT>::getSectionContentsAsArray(const Elf_Shdr *Sec) const {
356 if (Sec->sh_entsize != sizeof(T) && sizeof(T) != 1)
3
Assuming the condition is false
357 return createError("invalid sh_entsize");
358
359 uintX_t Offset = Sec->sh_offset;
360 uintX_t Size = Sec->sh_size;
361
362 if (Size % sizeof(T))
4
Taking false branch
363 return createError("size is not a multiple of sh_entsize");
364 if ((std::numeric_limits<uintX_t>::max() - Offset < Size) ||
5
Assuming the condition is true
365 Offset + Size > Buf.size())
366 return createError("invalid section offset");
6
Calling 'createError'
367
368 if (Offset % alignof(T))
369 return createError("unaligned data");
370
371 const T *Start = reinterpret_cast<const T *>(base() + Offset);
372 return makeArrayRef(Start, Size / sizeof(T));
373}
374
375template <class ELFT>
376Expected<ArrayRef<uint8_t>>
377ELFFile<ELFT>::getSectionContents(const Elf_Shdr *Sec) const {
378 return getSectionContentsAsArray<uint8_t>(Sec);
2
Calling 'ELFFile::getSectionContentsAsArray'
379}
380
381template <class ELFT>
382StringRef ELFFile<ELFT>::getRelocationTypeName(uint32_t Type) const {
383 return getELFRelocationTypeName(getHeader()->e_machine, Type);
384}
385
386template <class ELFT>
387void ELFFile<ELFT>::getRelocationTypeName(uint32_t Type,
388 SmallVectorImpl<char> &Result) const {
389 if (!isMipsELF64()) {
390 StringRef Name = getRelocationTypeName(Type);
391 Result.append(Name.begin(), Name.end());
392 } else {
393 // The Mips N64 ABI allows up to three operations to be specified per
394 // relocation record. Unfortunately there's no easy way to test for the
395 // presence of N64 ELFs as they have no special flag that identifies them
396 // as being N64. We can safely assume at the moment that all Mips
397 // ELFCLASS64 ELFs are N64. New Mips64 ABIs should provide enough
398 // information to disambiguate between old vs new ABIs.
399 uint8_t Type1 = (Type >> 0) & 0xFF;
400 uint8_t Type2 = (Type >> 8) & 0xFF;
401 uint8_t Type3 = (Type >> 16) & 0xFF;
402
403 // Concat all three relocation type names.
404 StringRef Name = getRelocationTypeName(Type1);
405 Result.append(Name.begin(), Name.end());
406
407 Name = getRelocationTypeName(Type2);
408 Result.append(1, '/');
409 Result.append(Name.begin(), Name.end());
410
411 Name = getRelocationTypeName(Type3);
412 Result.append(1, '/');
413 Result.append(Name.begin(), Name.end());
414 }
415}
416
417template <class ELFT>
418uint32_t ELFFile<ELFT>::getRelativeRelocationType() const {
419 return getELFRelativeRelocationType(getHeader()->e_machine);
420}
421
422template <class ELFT>
423Expected<const typename ELFT::Sym *>
424ELFFile<ELFT>::getRelocationSymbol(const Elf_Rel *Rel,
425 const Elf_Shdr *SymTab) const {
426 uint32_t Index = Rel->getSymbol(isMips64EL());
427 if (Index == 0)
428 return nullptr;
429 return getEntry<Elf_Sym>(SymTab, Index);
430}
431
432template <class ELFT>
433Expected<StringRef>
434ELFFile<ELFT>::getSectionStringTable(Elf_Shdr_Range Sections) const {
435 uint32_t Index = getHeader()->e_shstrndx;
436 if (Index == ELF::SHN_XINDEX)
437 Index = Sections[0].sh_link;
438
439 if (!Index) // no section string table.
440 return "";
441 if (Index >= Sections.size())
442 return createError("invalid section index");
443 return getStringTable(&Sections[Index]);
444}
445
446template <class ELFT> ELFFile<ELFT>::ELFFile(StringRef Object) : Buf(Object) {}
447
448template <class ELFT>
449Expected<ELFFile<ELFT>> ELFFile<ELFT>::create(StringRef Object) {
450 if (sizeof(Elf_Ehdr) > Object.size())
451 return createError("Invalid buffer");
452 return ELFFile(Object);
453}
454
455template <class ELFT>
456Expected<typename ELFT::ShdrRange> ELFFile<ELFT>::sections() const {
457 const uintX_t SectionTableOffset = getHeader()->e_shoff;
458 if (SectionTableOffset == 0)
459 return ArrayRef<Elf_Shdr>();
460
461 if (getHeader()->e_shentsize != sizeof(Elf_Shdr))
462 return createError(
463 "invalid section header entry size (e_shentsize) in ELF header");
464
465 const uint64_t FileSize = Buf.size();
466
467 if (SectionTableOffset + sizeof(Elf_Shdr) > FileSize)
468 return createError("section header table goes past the end of the file");
469
470 // Invalid address alignment of section headers
471 if (SectionTableOffset & (alignof(Elf_Shdr) - 1))
472 return createError("invalid alignment of section headers");
473
474 const Elf_Shdr *First =
475 reinterpret_cast<const Elf_Shdr *>(base() + SectionTableOffset);
476
477 uintX_t NumSections = getHeader()->e_shnum;
478 if (NumSections == 0)
479 NumSections = First->sh_size;
480
481 if (NumSections > UINT64_MAX(18446744073709551615UL) / sizeof(Elf_Shdr))
482 return createError("section table goes past the end of file");
483
484 const uint64_t SectionTableSize = NumSections * sizeof(Elf_Shdr);
485
486 // Section table goes past end of file!
487 if (SectionTableOffset + SectionTableSize > FileSize)
488 return createError("section table goes past the end of file");
489
490 return makeArrayRef(First, NumSections);
491}
492
493template <class ELFT>
494template <typename T>
495Expected<const T *> ELFFile<ELFT>::getEntry(uint32_t Section,
496 uint32_t Entry) const {
497 auto SecOrErr = getSection(Section);
498 if (!SecOrErr)
499 return SecOrErr.takeError();
500 return getEntry<T>(*SecOrErr, Entry);
501}
502
503template <class ELFT>
504template <typename T>
505Expected<const T *> ELFFile<ELFT>::getEntry(const Elf_Shdr *Section,
506 uint32_t Entry) const {
507 if (sizeof(T) != Section->sh_entsize)
508 return createError("invalid sh_entsize");
509 size_t Pos = Section->sh_offset + Entry * sizeof(T);
510 if (Pos + sizeof(T) > Buf.size())
511 return createError("invalid section offset");
512 return reinterpret_cast<const T *>(base() + Pos);
513}
514
515template <class ELFT>
516Expected<const typename ELFT::Shdr *>
517ELFFile<ELFT>::getSection(uint32_t Index) const {
518 auto TableOrErr = sections();
519 if (!TableOrErr)
520 return TableOrErr.takeError();
521 return object::getSection<ELFT>(*TableOrErr, Index);
522}
523
524template <class ELFT>
525Expected<const typename ELFT::Shdr *>
526ELFFile<ELFT>::getSection(const StringRef SectionName) const {
527 auto TableOrErr = sections();
528 if (!TableOrErr)
529 return TableOrErr.takeError();
530 for (auto &Sec : *TableOrErr) {
531 auto SecNameOrErr = getSectionName(&Sec);
532 if (!SecNameOrErr)
533 return SecNameOrErr.takeError();
534 if (*SecNameOrErr == SectionName)
535 return &Sec;
536 }
537 return createError("invalid section name");
538}
539
540template <class ELFT>
541Expected<StringRef>
542ELFFile<ELFT>::getStringTable(const Elf_Shdr *Section) const {
543 if (Section->sh_type != ELF::SHT_STRTAB)
544 return createError("invalid sh_type for string table, expected SHT_STRTAB");
545 auto V = getSectionContentsAsArray<char>(Section);
546 if (!V)
547 return V.takeError();
548 ArrayRef<char> Data = *V;
549 if (Data.empty())
550 return createError("empty string table");
551 if (Data.back() != '\0')
552 return createError("string table non-null terminated");
553 return StringRef(Data.begin(), Data.size());
554}
555
556template <class ELFT>
557Expected<ArrayRef<typename ELFT::Word>>
558ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section) const {
559 auto SectionsOrErr = sections();
560 if (!SectionsOrErr)
561 return SectionsOrErr.takeError();
562 return getSHNDXTable(Section, *SectionsOrErr);
563}
564
565template <class ELFT>
566Expected<ArrayRef<typename ELFT::Word>>
567ELFFile<ELFT>::getSHNDXTable(const Elf_Shdr &Section,
568 Elf_Shdr_Range Sections) const {
569 assert(Section.sh_type == ELF::SHT_SYMTAB_SHNDX)((Section.sh_type == ELF::SHT_SYMTAB_SHNDX) ? static_cast<
void> (0) : __assert_fail ("Section.sh_type == ELF::SHT_SYMTAB_SHNDX"
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Object/ELF.h"
, 569, __PRETTY_FUNCTION__))
;
570 auto VOrErr = getSectionContentsAsArray<Elf_Word>(&Section);
571 if (!VOrErr)
572 return VOrErr.takeError();
573 ArrayRef<Elf_Word> V = *VOrErr;
574 auto SymTableOrErr = object::getSection<ELFT>(Sections, Section.sh_link);
575 if (!SymTableOrErr)
576 return SymTableOrErr.takeError();
577 const Elf_Shdr &SymTable = **SymTableOrErr;
578 if (SymTable.sh_type != ELF::SHT_SYMTAB &&
579 SymTable.sh_type != ELF::SHT_DYNSYM)
580 return createError("invalid sh_type");
581 if (V.size() != (SymTable.sh_size / sizeof(Elf_Sym)))
582 return createError("invalid section contents size");
583 return V;
584}
585
586template <class ELFT>
587Expected<StringRef>
588ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec) const {
589 auto SectionsOrErr = sections();
590 if (!SectionsOrErr)
591 return SectionsOrErr.takeError();
592 return getStringTableForSymtab(Sec, *SectionsOrErr);
593}
594
595template <class ELFT>
596Expected<StringRef>
597ELFFile<ELFT>::getStringTableForSymtab(const Elf_Shdr &Sec,
598 Elf_Shdr_Range Sections) const {
599
600 if (Sec.sh_type != ELF::SHT_SYMTAB && Sec.sh_type != ELF::SHT_DYNSYM)
601 return createError(
602 "invalid sh_type for symbol table, expected SHT_SYMTAB or SHT_DYNSYM");
603 auto SectionOrErr = object::getSection<ELFT>(Sections, Sec.sh_link);
604 if (!SectionOrErr)
605 return SectionOrErr.takeError();
606 return getStringTable(*SectionOrErr);
607}
608
609template <class ELFT>
610Expected<StringRef>
611ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section) const {
612 auto SectionsOrErr = sections();
613 if (!SectionsOrErr)
614 return SectionsOrErr.takeError();
615 auto Table = getSectionStringTable(*SectionsOrErr);
616 if (!Table)
617 return Table.takeError();
618 return getSectionName(Section, *Table);
619}
620
621template <class ELFT>
622Expected<StringRef> ELFFile<ELFT>::getSectionName(const Elf_Shdr *Section,
623 StringRef DotShstrtab) const {
624 uint32_t Offset = Section->sh_name;
625 if (Offset == 0)
626 return StringRef();
627 if (Offset >= DotShstrtab.size())
628 return createError("invalid string offset");
629 return StringRef(DotShstrtab.data() + Offset);
630}
631
632/// This function returns the hash value for a symbol in the .dynsym section
633/// Name of the API remains consistent as specified in the libelf
634/// REF : http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash
635inline unsigned hashSysV(StringRef SymbolName) {
636 unsigned h = 0, g;
637 for (char C : SymbolName) {
638 h = (h << 4) + C;
639 g = h & 0xf0000000L;
640 if (g != 0)
641 h ^= g >> 24;
642 h &= ~g;
643 }
644 return h;
645}
646
647} // end namespace object
648} // end namespace llvm
649
650#endif // LLVM_OBJECT_ELF_H

/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h

1//===- llvm/Support/Error.h - Recoverable error handling --------*- C++ -*-===//
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 file defines an API used to report recoverable errors.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_ERROR_H
15#define LLVM_SUPPORT_ERROR_H
16
17#include "llvm-c/Error.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/ADT/StringExtras.h"
21#include "llvm/ADT/Twine.h"
22#include "llvm/Config/abi-breaking.h"
23#include "llvm/Support/AlignOf.h"
24#include "llvm/Support/Compiler.h"
25#include "llvm/Support/Debug.h"
26#include "llvm/Support/ErrorHandling.h"
27#include "llvm/Support/ErrorOr.h"
28#include "llvm/Support/Format.h"
29#include "llvm/Support/raw_ostream.h"
30#include <algorithm>
31#include <cassert>
32#include <cstdint>
33#include <cstdlib>
34#include <functional>
35#include <memory>
36#include <new>
37#include <string>
38#include <system_error>
39#include <type_traits>
40#include <utility>
41#include <vector>
42
43namespace llvm {
44
45class ErrorSuccess;
46
47/// Base class for error info classes. Do not extend this directly: Extend
48/// the ErrorInfo template subclass instead.
49class ErrorInfoBase {
50public:
51 virtual ~ErrorInfoBase() = default;
52
53 /// Print an error message to an output stream.
54 virtual void log(raw_ostream &OS) const = 0;
55
56 /// Return the error message as a string.
57 virtual std::string message() const {
58 std::string Msg;
59 raw_string_ostream OS(Msg);
60 log(OS);
61 return OS.str();
62 }
63
64 /// Convert this error to a std::error_code.
65 ///
66 /// This is a temporary crutch to enable interaction with code still
67 /// using std::error_code. It will be removed in the future.
68 virtual std::error_code convertToErrorCode() const = 0;
69
70 // Returns the class ID for this type.
71 static const void *classID() { return &ID; }
72
73 // Returns the class ID for the dynamic type of this ErrorInfoBase instance.
74 virtual const void *dynamicClassID() const = 0;
75
76 // Check whether this instance is a subclass of the class identified by
77 // ClassID.
78 virtual bool isA(const void *const ClassID) const {
79 return ClassID == classID();
80 }
81
82 // Check whether this instance is a subclass of ErrorInfoT.
83 template <typename ErrorInfoT> bool isA() const {
84 return isA(ErrorInfoT::classID());
85 }
86
87private:
88 virtual void anchor();
89
90 static char ID;
91};
92
93/// Lightweight error class with error context and mandatory checking.
94///
95/// Instances of this class wrap a ErrorInfoBase pointer. Failure states
96/// are represented by setting the pointer to a ErrorInfoBase subclass
97/// instance containing information describing the failure. Success is
98/// represented by a null pointer value.
99///
100/// Instances of Error also contains a 'Checked' flag, which must be set
101/// before the destructor is called, otherwise the destructor will trigger a
102/// runtime error. This enforces at runtime the requirement that all Error
103/// instances be checked or returned to the caller.
104///
105/// There are two ways to set the checked flag, depending on what state the
106/// Error instance is in. For Error instances indicating success, it
107/// is sufficient to invoke the boolean conversion operator. E.g.:
108///
109/// @code{.cpp}
110/// Error foo(<...>);
111///
112/// if (auto E = foo(<...>))
113/// return E; // <- Return E if it is in the error state.
114/// // We have verified that E was in the success state. It can now be safely
115/// // destroyed.
116/// @endcode
117///
118/// A success value *can not* be dropped. For example, just calling 'foo(<...>)'
119/// without testing the return value will raise a runtime error, even if foo
120/// returns success.
121///
122/// For Error instances representing failure, you must use either the
123/// handleErrors or handleAllErrors function with a typed handler. E.g.:
124///
125/// @code{.cpp}
126/// class MyErrorInfo : public ErrorInfo<MyErrorInfo> {
127/// // Custom error info.
128/// };
129///
130/// Error foo(<...>) { return make_error<MyErrorInfo>(...); }
131///
132/// auto E = foo(<...>); // <- foo returns failure with MyErrorInfo.
133/// auto NewE =
134/// handleErrors(E,
135/// [](const MyErrorInfo &M) {
136/// // Deal with the error.
137/// },
138/// [](std::unique_ptr<OtherError> M) -> Error {
139/// if (canHandle(*M)) {
140/// // handle error.
141/// return Error::success();
142/// }
143/// // Couldn't handle this error instance. Pass it up the stack.
144/// return Error(std::move(M));
145/// );
146/// // Note - we must check or return NewE in case any of the handlers
147/// // returned a new error.
148/// @endcode
149///
150/// The handleAllErrors function is identical to handleErrors, except
151/// that it has a void return type, and requires all errors to be handled and
152/// no new errors be returned. It prevents errors (assuming they can all be
153/// handled) from having to be bubbled all the way to the top-level.
154///
155/// *All* Error instances must be checked before destruction, even if
156/// they're moved-assigned or constructed from Success values that have already
157/// been checked. This enforces checking through all levels of the call stack.
158class LLVM_NODISCARD[[clang::warn_unused_result]] Error {
159 // Both ErrorList and FileError need to be able to yank ErrorInfoBase
160 // pointers out of this class to add to the error list.
161 friend class ErrorList;
162 friend class FileError;
163
164 // handleErrors needs to be able to set the Checked flag.
165 template <typename... HandlerTs>
166 friend Error handleErrors(Error E, HandlerTs &&... Handlers);
167
168 // Expected<T> needs to be able to steal the payload when constructed from an
169 // error.
170 template <typename T> friend class Expected;
171
172 // wrap needs to be able to steal the payload.
173 friend LLVMErrorRef wrap(Error);
174
175protected:
176 /// Create a success value. Prefer using 'Error::success()' for readability
177 Error() {
178 setPtr(nullptr);
179 setChecked(false);
180 }
181
182public:
183 /// Create a success value.
184 static ErrorSuccess success();
185
186 // Errors are not copy-constructable.
187 Error(const Error &Other) = delete;
188
189 /// Move-construct an error value. The newly constructed error is considered
190 /// unchecked, even if the source error had been checked. The original error
191 /// becomes a checked Success value, regardless of its original state.
192 Error(Error &&Other) {
193 setChecked(true);
194 *this = std::move(Other);
195 }
196
197 /// Create an error value. Prefer using the 'make_error' function, but
198 /// this constructor can be useful when "re-throwing" errors from handlers.
199 Error(std::unique_ptr<ErrorInfoBase> Payload) {
200 setPtr(Payload.release());
201 setChecked(false);
12
Potential leak of memory pointed to by 'Payload._M_t._M_head_impl'
202 }
203
204 // Errors are not copy-assignable.
205 Error &operator=(const Error &Other) = delete;
206
207 /// Move-assign an error value. The current error must represent success, you
208 /// you cannot overwrite an unhandled error. The current error is then
209 /// considered unchecked. The source error becomes a checked success value,
210 /// regardless of its original state.
211 Error &operator=(Error &&Other) {
212 // Don't allow overwriting of unchecked values.
213 assertIsChecked();
214 setPtr(Other.getPtr());
215
216 // This Error is unchecked, even if the source error was checked.
217 setChecked(false);
218
219 // Null out Other's payload and set its checked bit.
220 Other.setPtr(nullptr);
221 Other.setChecked(true);
222
223 return *this;
224 }
225
226 /// Destroy a Error. Fails with a call to abort() if the error is
227 /// unchecked.
228 ~Error() {
229 assertIsChecked();
230 delete getPtr();
231 }
232
233 /// Bool conversion. Returns true if this Error is in a failure state,
234 /// and false if it is in an accept state. If the error is in a Success state
235 /// it will be considered checked.
236 explicit operator bool() {
237 setChecked(getPtr() == nullptr);
238 return getPtr() != nullptr;
239 }
240
241 /// Check whether one error is a subclass of another.
242 template <typename ErrT> bool isA() const {
243 return getPtr() && getPtr()->isA(ErrT::classID());
244 }
245
246 /// Returns the dynamic class id of this error, or null if this is a success
247 /// value.
248 const void* dynamicClassID() const {
249 if (!getPtr())
250 return nullptr;
251 return getPtr()->dynamicClassID();
252 }
253
254private:
255#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
256 // assertIsChecked() happens very frequently, but under normal circumstances
257 // is supposed to be a no-op. So we want it to be inlined, but having a bunch
258 // of debug prints can cause the function to be too large for inlining. So
259 // it's important that we define this function out of line so that it can't be
260 // inlined.
261 LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
262 void fatalUncheckedError() const;
263#endif
264
265 void assertIsChecked() {
266#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
267 if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false))
268 fatalUncheckedError();
269#endif
270 }
271
272 ErrorInfoBase *getPtr() const {
273 return reinterpret_cast<ErrorInfoBase*>(
274 reinterpret_cast<uintptr_t>(Payload) &
275 ~static_cast<uintptr_t>(0x1));
276 }
277
278 void setPtr(ErrorInfoBase *EI) {
279#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
280 Payload = reinterpret_cast<ErrorInfoBase*>(
281 (reinterpret_cast<uintptr_t>(EI) &
282 ~static_cast<uintptr_t>(0x1)) |
283 (reinterpret_cast<uintptr_t>(Payload) & 0x1));
284#else
285 Payload = EI;
286#endif
287 }
288
289 bool getChecked() const {
290#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
291 return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0;
292#else
293 return true;
294#endif
295 }
296
297 void setChecked(bool V) {
298 Payload = reinterpret_cast<ErrorInfoBase*>(
299 (reinterpret_cast<uintptr_t>(Payload) &
300 ~static_cast<uintptr_t>(0x1)) |
301 (V ? 0 : 1));
302 }
303
304 std::unique_ptr<ErrorInfoBase> takePayload() {
305 std::unique_ptr<ErrorInfoBase> Tmp(getPtr());
306 setPtr(nullptr);
307 setChecked(true);
308 return Tmp;
309 }
310
311 friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) {
312 if (auto P = E.getPtr())
313 P->log(OS);
314 else
315 OS << "success";
316 return OS;
317 }
318
319 ErrorInfoBase *Payload = nullptr;
320};
321
322/// Subclass of Error for the sole purpose of identifying the success path in
323/// the type system. This allows to catch invalid conversion to Expected<T> at
324/// compile time.
325class ErrorSuccess final : public Error {};
326
327inline ErrorSuccess Error::success() { return ErrorSuccess(); }
328
329/// Make a Error instance representing failure using the given error info
330/// type.
331template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) {
332 return Error(llvm::make_unique<ErrT>(std::forward<ArgTs>(Args)...));
8
Calling 'make_unique<llvm::StringError, llvm::StringRef &, llvm::object::object_error>'
10
Returned allocated memory
11
Calling constructor for 'Error'
333}
334
335/// Base class for user error types. Users should declare their error types
336/// like:
337///
338/// class MyError : public ErrorInfo<MyError> {
339/// ....
340/// };
341///
342/// This class provides an implementation of the ErrorInfoBase::kind
343/// method, which is used by the Error RTTI system.
344template <typename ThisErrT, typename ParentErrT = ErrorInfoBase>
345class ErrorInfo : public ParentErrT {
346public:
347 using ParentErrT::ParentErrT; // inherit constructors
348
349 static const void *classID() { return &ThisErrT::ID; }
350
351 const void *dynamicClassID() const override { return &ThisErrT::ID; }
352
353 bool isA(const void *const ClassID) const override {
354 return ClassID == classID() || ParentErrT::isA(ClassID);
355 }
356};
357
358/// Special ErrorInfo subclass representing a list of ErrorInfos.
359/// Instances of this class are constructed by joinError.
360class ErrorList final : public ErrorInfo<ErrorList> {
361 // handleErrors needs to be able to iterate the payload list of an
362 // ErrorList.
363 template <typename... HandlerTs>
364 friend Error handleErrors(Error E, HandlerTs &&... Handlers);
365
366 // joinErrors is implemented in terms of join.
367 friend Error joinErrors(Error, Error);
368
369public:
370 void log(raw_ostream &OS) const override {
371 OS << "Multiple errors:\n";
372 for (auto &ErrPayload : Payloads) {
373 ErrPayload->log(OS);
374 OS << "\n";
375 }
376 }
377
378 std::error_code convertToErrorCode() const override;
379
380 // Used by ErrorInfo::classID.
381 static char ID;
382
383private:
384 ErrorList(std::unique_ptr<ErrorInfoBase> Payload1,
385 std::unique_ptr<ErrorInfoBase> Payload2) {
386 assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 387, __PRETTY_FUNCTION__))
387 "ErrorList constructor payloads should be singleton errors")((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 387, __PRETTY_FUNCTION__))
;
388 Payloads.push_back(std::move(Payload1));
389 Payloads.push_back(std::move(Payload2));
390 }
391
392 static Error join(Error E1, Error E2) {
393 if (!E1)
394 return E2;
395 if (!E2)
396 return E1;
397 if (E1.isA<ErrorList>()) {
398 auto &E1List = static_cast<ErrorList &>(*E1.getPtr());
399 if (E2.isA<ErrorList>()) {
400 auto E2Payload = E2.takePayload();
401 auto &E2List = static_cast<ErrorList &>(*E2Payload);
402 for (auto &Payload : E2List.Payloads)
403 E1List.Payloads.push_back(std::move(Payload));
404 } else
405 E1List.Payloads.push_back(E2.takePayload());
406
407 return E1;
408 }
409 if (E2.isA<ErrorList>()) {
410 auto &E2List = static_cast<ErrorList &>(*E2.getPtr());
411 E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload());
412 return E2;
413 }
414 return Error(std::unique_ptr<ErrorList>(
415 new ErrorList(E1.takePayload(), E2.takePayload())));
416 }
417
418 std::vector<std::unique_ptr<ErrorInfoBase>> Payloads;
419};
420
421/// Concatenate errors. The resulting Error is unchecked, and contains the
422/// ErrorInfo(s), if any, contained in E1, followed by the
423/// ErrorInfo(s), if any, contained in E2.
424inline Error joinErrors(Error E1, Error E2) {
425 return ErrorList::join(std::move(E1), std::move(E2));
426}
427
428/// Tagged union holding either a T or a Error.
429///
430/// This class parallels ErrorOr, but replaces error_code with Error. Since
431/// Error cannot be copied, this class replaces getError() with
432/// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the
433/// error class type.
434template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected {
435 template <class T1> friend class ExpectedAsOutParameter;
436 template <class OtherT> friend class Expected;
437
438 static const bool isRef = std::is_reference<T>::value;
439
440 using wrap = std::reference_wrapper<typename std::remove_reference<T>::type>;
441
442 using error_type = std::unique_ptr<ErrorInfoBase>;
443
444public:
445 using storage_type = typename std::conditional<isRef, wrap, T>::type;
446 using value_type = T;
447
448private:
449 using reference = typename std::remove_reference<T>::type &;
450 using const_reference = const typename std::remove_reference<T>::type &;
451 using pointer = typename std::remove_reference<T>::type *;
452 using const_pointer = const typename std::remove_reference<T>::type *;
453
454public:
455 /// Create an Expected<T> error value from the given Error.
456 Expected(Error Err)
457 : HasError(true)
458#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
459 // Expected is unchecked upon construction in Debug builds.
460 , Unchecked(true)
461#endif
462 {
463 assert(Err && "Cannot create Expected<T> from Error success value.")((Err && "Cannot create Expected<T> from Error success value."
) ? static_cast<void> (0) : __assert_fail ("Err && \"Cannot create Expected<T> from Error success value.\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 463, __PRETTY_FUNCTION__))
;
464 new (getErrorStorage()) error_type(Err.takePayload());
465 }
466
467 /// Forbid to convert from Error::success() implicitly, this avoids having
468 /// Expected<T> foo() { return Error::success(); } which compiles otherwise
469 /// but triggers the assertion above.
470 Expected(ErrorSuccess) = delete;
471
472 /// Create an Expected<T> success value from the given OtherT value, which
473 /// must be convertible to T.
474 template <typename OtherT>
475 Expected(OtherT &&Val,
476 typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
477 * = nullptr)
478 : HasError(false)
479#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
480 // Expected is unchecked upon construction in Debug builds.
481 , Unchecked(true)
482#endif
483 {
484 new (getStorage()) storage_type(std::forward<OtherT>(Val));
485 }
486
487 /// Move construct an Expected<T> value.
488 Expected(Expected &&Other) { moveConstruct(std::move(Other)); }
489
490 /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
491 /// must be convertible to T.
492 template <class OtherT>
493 Expected(Expected<OtherT> &&Other,
494 typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
495 * = nullptr) {
496 moveConstruct(std::move(Other));
497 }
498
499 /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
500 /// isn't convertible to T.
501 template <class OtherT>
502 explicit Expected(
503 Expected<OtherT> &&Other,
504 typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * =
505 nullptr) {
506 moveConstruct(std::move(Other));
507 }
508
509 /// Move-assign from another Expected<T>.
510 Expected &operator=(Expected &&Other) {
511 moveAssign(std::move(Other));
512 return *this;
513 }
514
515 /// Destroy an Expected<T>.
516 ~Expected() {
517 assertIsChecked();
518 if (!HasError)
519 getStorage()->~storage_type();
520 else
521 getErrorStorage()->~error_type();
522 }
523
524 /// Return false if there is an error.
525 explicit operator bool() {
526#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
527 Unchecked = HasError;
528#endif
529 return !HasError;
530 }
531
532 /// Returns a reference to the stored T value.
533 reference get() {
534 assertIsChecked();
535 return *getStorage();
536 }
537
538 /// Returns a const reference to the stored T value.
539 const_reference get() const {
540 assertIsChecked();
541 return const_cast<Expected<T> *>(this)->get();
542 }
543
544 /// Check that this Expected<T> is an error of type ErrT.
545 template <typename ErrT> bool errorIsA() const {
546 return HasError && (*getErrorStorage())->template isA<ErrT>();
547 }
548
549 /// Take ownership of the stored error.
550 /// After calling this the Expected<T> is in an indeterminate state that can
551 /// only be safely destructed. No further calls (beside the destructor) should
552 /// be made on the Expected<T> vaule.
553 Error takeError() {
554#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
555 Unchecked = false;
556#endif
557 return HasError ? Error(std::move(*getErrorStorage())) : Error::success();
558 }
559
560 /// Returns a pointer to the stored T value.
561 pointer operator->() {
562 assertIsChecked();
563 return toPointer(getStorage());
564 }
565
566 /// Returns a const pointer to the stored T value.
567 const_pointer operator->() const {
568 assertIsChecked();
569 return toPointer(getStorage());
570 }
571
572 /// Returns a reference to the stored T value.
573 reference operator*() {
574 assertIsChecked();
575 return *getStorage();
576 }
577
578 /// Returns a const reference to the stored T value.
579 const_reference operator*() const {
580 assertIsChecked();
581 return *getStorage();
582 }
583
584private:
585 template <class T1>
586 static bool compareThisIfSameType(const T1 &a, const T1 &b) {
587 return &a == &b;
588 }
589
590 template <class T1, class T2>
591 static bool compareThisIfSameType(const T1 &a, const T2 &b) {
592 return false;
593 }
594
595 template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) {
596 HasError = Other.HasError;
597#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
598 Unchecked = true;
599 Other.Unchecked = false;
600#endif
601
602 if (!HasError)
603 new (getStorage()) storage_type(std::move(*Other.getStorage()));
604 else
605 new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage()));
606 }
607
608 template <class OtherT> void moveAssign(Expected<OtherT> &&Other) {
609 assertIsChecked();
610
611 if (compareThisIfSameType(*this, Other))
612 return;
613
614 this->~Expected();
615 new (this) Expected(std::move(Other));
616 }
617
618 pointer toPointer(pointer Val) { return Val; }
619
620 const_pointer toPointer(const_pointer Val) const { return Val; }
621
622 pointer toPointer(wrap *Val) { return &Val->get(); }
623
624 const_pointer toPointer(const wrap *Val) const { return &Val->get(); }
625
626 storage_type *getStorage() {
627 assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 627, __PRETTY_FUNCTION__))
;
628 return reinterpret_cast<storage_type *>(TStorage.buffer);
629 }
630
631 const storage_type *getStorage() const {
632 assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 632, __PRETTY_FUNCTION__))
;
633 return reinterpret_cast<const storage_type *>(TStorage.buffer);
634 }
635
636 error_type *getErrorStorage() {
637 assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 637, __PRETTY_FUNCTION__))
;
638 return reinterpret_cast<error_type *>(ErrorStorage.buffer);
639 }
640
641 const error_type *getErrorStorage() const {
642 assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 642, __PRETTY_FUNCTION__))
;
643 return reinterpret_cast<const error_type *>(ErrorStorage.buffer);
644 }
645
646 // Used by ExpectedAsOutParameter to reset the checked flag.
647 void setUnchecked() {
648#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
649 Unchecked = true;
650#endif
651 }
652
653#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
654 LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
655 LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline))
656 void fatalUncheckedExpected() const {
657 dbgs() << "Expected<T> must be checked before access or destruction.\n";
658 if (HasError) {
659 dbgs() << "Unchecked Expected<T> contained error:\n";
660 (*getErrorStorage())->log(dbgs());
661 } else
662 dbgs() << "Expected<T> value was in success state. (Note: Expected<T> "
663 "values in success mode must still be checked prior to being "
664 "destroyed).\n";
665 abort();
666 }
667#endif
668
669 void assertIsChecked() {
670#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
671 if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false))
672 fatalUncheckedExpected();
673#endif
674 }
675
676 union {
677 AlignedCharArrayUnion<storage_type> TStorage;
678 AlignedCharArrayUnion<error_type> ErrorStorage;
679 };
680 bool HasError : 1;
681#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
682 bool Unchecked : 1;
683#endif
684};
685
686/// Report a serious error, calling any installed error handler. See
687/// ErrorHandling.h.
688LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) void report_fatal_error(Error Err,
689 bool gen_crash_diag = true);
690
691/// Report a fatal error if Err is a failure value.
692///
693/// This function can be used to wrap calls to fallible functions ONLY when it
694/// is known that the Error will always be a success value. E.g.
695///
696/// @code{.cpp}
697/// // foo only attempts the fallible operation if DoFallibleOperation is
698/// // true. If DoFallibleOperation is false then foo always returns
699/// // Error::success().
700/// Error foo(bool DoFallibleOperation);
701///
702/// cantFail(foo(false));
703/// @endcode
704inline void cantFail(Error Err, const char *Msg = nullptr) {
705 if (Err) {
706 if (!Msg)
707 Msg = "Failure value returned from cantFail wrapped call";
708 llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 708)
;
709 }
710}
711
712/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
713/// returns the contained value.
714///
715/// This function can be used to wrap calls to fallible functions ONLY when it
716/// is known that the Error will always be a success value. E.g.
717///
718/// @code{.cpp}
719/// // foo only attempts the fallible operation if DoFallibleOperation is
720/// // true. If DoFallibleOperation is false then foo always returns an int.
721/// Expected<int> foo(bool DoFallibleOperation);
722///
723/// int X = cantFail(foo(false));
724/// @endcode
725template <typename T>
726T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) {
727 if (ValOrErr)
728 return std::move(*ValOrErr);
729 else {
730 if (!Msg)
731 Msg = "Failure value returned from cantFail wrapped call";
732 llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 732)
;
733 }
734}
735
736/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
737/// returns the contained reference.
738///
739/// This function can be used to wrap calls to fallible functions ONLY when it
740/// is known that the Error will always be a success value. E.g.
741///
742/// @code{.cpp}
743/// // foo only attempts the fallible operation if DoFallibleOperation is
744/// // true. If DoFallibleOperation is false then foo always returns a Bar&.
745/// Expected<Bar&> foo(bool DoFallibleOperation);
746///
747/// Bar &X = cantFail(foo(false));
748/// @endcode
749template <typename T>
750T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) {
751 if (ValOrErr)
752 return *ValOrErr;
753 else {
754 if (!Msg)
755 Msg = "Failure value returned from cantFail wrapped call";
756 llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 756)
;
757 }
758}
759
760/// Helper for testing applicability of, and applying, handlers for
761/// ErrorInfo types.
762template <typename HandlerT>
763class ErrorHandlerTraits
764 : public ErrorHandlerTraits<decltype(
765 &std::remove_reference<HandlerT>::type::operator())> {};
766
767// Specialization functions of the form 'Error (const ErrT&)'.
768template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> {
769public:
770 static bool appliesTo(const ErrorInfoBase &E) {
771 return E.template isA<ErrT>();
772 }
773
774 template <typename HandlerT>
775 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
776 assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 776, __PRETTY_FUNCTION__))
;
777 return H(static_cast<ErrT &>(*E));
778 }
779};
780
781// Specialization functions of the form 'void (const ErrT&)'.
782template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> {
783public:
784 static bool appliesTo(const ErrorInfoBase &E) {
785 return E.template isA<ErrT>();
786 }
787
788 template <typename HandlerT>
789 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
790 assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 790, __PRETTY_FUNCTION__))
;
791 H(static_cast<ErrT &>(*E));
792 return Error::success();
793 }
794};
795
796/// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'.
797template <typename ErrT>
798class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> {
799public:
800 static bool appliesTo(const ErrorInfoBase &E) {
801 return E.template isA<ErrT>();
802 }
803
804 template <typename HandlerT>
805 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
806 assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 806, __PRETTY_FUNCTION__))
;
807 std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
808 return H(std::move(SubE));
809 }
810};
811
812/// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'.
813template <typename ErrT>
814class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> {
815public:
816 static bool appliesTo(const ErrorInfoBase &E) {
817 return E.template isA<ErrT>();
818 }
819
820 template <typename HandlerT>
821 static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
822 assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 822, __PRETTY_FUNCTION__))
;
823 std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
824 H(std::move(SubE));
825 return Error::success();
826 }
827};
828
829// Specialization for member functions of the form 'RetT (const ErrT&)'.
830template <typename C, typename RetT, typename ErrT>
831class ErrorHandlerTraits<RetT (C::*)(ErrT &)>
832 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
833
834// Specialization for member functions of the form 'RetT (const ErrT&) const'.
835template <typename C, typename RetT, typename ErrT>
836class ErrorHandlerTraits<RetT (C::*)(ErrT &) const>
837 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
838
839// Specialization for member functions of the form 'RetT (const ErrT&)'.
840template <typename C, typename RetT, typename ErrT>
841class ErrorHandlerTraits<RetT (C::*)(const ErrT &)>
842 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
843
844// Specialization for member functions of the form 'RetT (const ErrT&) const'.
845template <typename C, typename RetT, typename ErrT>
846class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const>
847 : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
848
849/// Specialization for member functions of the form
850/// 'RetT (std::unique_ptr<ErrT>)'.
851template <typename C, typename RetT, typename ErrT>
852class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)>
853 : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
854
855/// Specialization for member functions of the form
856/// 'RetT (std::unique_ptr<ErrT>) const'.
857template <typename C, typename RetT, typename ErrT>
858class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const>
859 : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
860
861inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) {
862 return Error(std::move(Payload));
863}
864
865template <typename HandlerT, typename... HandlerTs>
866Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload,
867 HandlerT &&Handler, HandlerTs &&... Handlers) {
868 if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload))
869 return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler),
870 std::move(Payload));
871 return handleErrorImpl(std::move(Payload),
872 std::forward<HandlerTs>(Handlers)...);
873}
874
875/// Pass the ErrorInfo(s) contained in E to their respective handlers. Any
876/// unhandled errors (or Errors returned by handlers) are re-concatenated and
877/// returned.
878/// Because this function returns an error, its result must also be checked
879/// or returned. If you intend to handle all errors use handleAllErrors
880/// (which returns void, and will abort() on unhandled errors) instead.
881template <typename... HandlerTs>
882Error handleErrors(Error E, HandlerTs &&... Hs) {
883 if (!E)
884 return Error::success();
885
886 std::unique_ptr<ErrorInfoBase> Payload = E.takePayload();
887
888 if (Payload->isA<ErrorList>()) {
889 ErrorList &List = static_cast<ErrorList &>(*Payload);
890 Error R;
891 for (auto &P : List.Payloads)
892 R = ErrorList::join(
893 std::move(R),
894 handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...));
895 return R;
896 }
897
898 return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...);
899}
900
901/// Behaves the same as handleErrors, except that by contract all errors
902/// *must* be handled by the given handlers (i.e. there must be no remaining
903/// errors after running the handlers, or llvm_unreachable is called).
904template <typename... HandlerTs>
905void handleAllErrors(Error E, HandlerTs &&... Handlers) {
906 cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...));
907}
908
909/// Check that E is a non-error, then drop it.
910/// If E is an error, llvm_unreachable will be called.
911inline void handleAllErrors(Error E) {
912 cantFail(std::move(E));
913}
914
915/// Handle any errors (if present) in an Expected<T>, then try a recovery path.
916///
917/// If the incoming value is a success value it is returned unmodified. If it
918/// is a failure value then it the contained error is passed to handleErrors.
919/// If handleErrors is able to handle the error then the RecoveryPath functor
920/// is called to supply the final result. If handleErrors is not able to
921/// handle all errors then the unhandled errors are returned.
922///
923/// This utility enables the follow pattern:
924///
925/// @code{.cpp}
926/// enum FooStrategy { Aggressive, Conservative };
927/// Expected<Foo> foo(FooStrategy S);
928///
929/// auto ResultOrErr =
930/// handleExpected(
931/// foo(Aggressive),
932/// []() { return foo(Conservative); },
933/// [](AggressiveStrategyError&) {
934/// // Implicitly conusme this - we'll recover by using a conservative
935/// // strategy.
936/// });
937///
938/// @endcode
939template <typename T, typename RecoveryFtor, typename... HandlerTs>
940Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath,
941 HandlerTs &&... Handlers) {
942 if (ValOrErr)
943 return ValOrErr;
944
945 if (auto Err = handleErrors(ValOrErr.takeError(),
946 std::forward<HandlerTs>(Handlers)...))
947 return std::move(Err);
948
949 return RecoveryPath();
950}
951
952/// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner
953/// will be printed before the first one is logged. A newline will be printed
954/// after each error.
955///
956/// This function is compatible with the helpers from Support/WithColor.h. You
957/// can pass any of them as the OS. Please consider using them instead of
958/// including 'error: ' in the ErrorBanner.
959///
960/// This is useful in the base level of your program to allow clean termination
961/// (allowing clean deallocation of resources, etc.), while reporting error
962/// information to the user.
963void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {});
964
965/// Write all error messages (if any) in E to a string. The newline character
966/// is used to separate error messages.
967inline std::string toString(Error E) {
968 SmallVector<std::string, 2> Errors;
969 handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) {
970 Errors.push_back(EI.message());
971 });
972 return join(Errors.begin(), Errors.end(), "\n");
973}
974
975/// Consume a Error without doing anything. This method should be used
976/// only where an error can be considered a reasonable and expected return
977/// value.
978///
979/// Uses of this method are potentially indicative of design problems: If it's
980/// legitimate to do nothing while processing an "error", the error-producer
981/// might be more clearly refactored to return an Optional<T>.
982inline void consumeError(Error Err) {
983 handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {});
984}
985
986/// Helper for converting an Error to a bool.
987///
988/// This method returns true if Err is in an error state, or false if it is
989/// in a success state. Puts Err in a checked state in both cases (unlike
990/// Error::operator bool(), which only does this for success states).
991inline bool errorToBool(Error Err) {
992 bool IsError = static_cast<bool>(Err);
993 if (IsError)
994 consumeError(std::move(Err));
995 return IsError;
996}
997
998/// Helper for Errors used as out-parameters.
999///
1000/// This helper is for use with the Error-as-out-parameter idiom, where an error
1001/// is passed to a function or method by reference, rather than being returned.
1002/// In such cases it is helpful to set the checked bit on entry to the function
1003/// so that the error can be written to (unchecked Errors abort on assignment)
1004/// and clear the checked bit on exit so that clients cannot accidentally forget
1005/// to check the result. This helper performs these actions automatically using
1006/// RAII:
1007///
1008/// @code{.cpp}
1009/// Result foo(Error &Err) {
1010/// ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set
1011/// // <body of foo>
1012/// // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed.
1013/// }
1014/// @endcode
1015///
1016/// ErrorAsOutParameter takes an Error* rather than Error& so that it can be
1017/// used with optional Errors (Error pointers that are allowed to be null). If
1018/// ErrorAsOutParameter took an Error reference, an instance would have to be
1019/// created inside every condition that verified that Error was non-null. By
1020/// taking an Error pointer we can just create one instance at the top of the
1021/// function.
1022class ErrorAsOutParameter {
1023public:
1024 ErrorAsOutParameter(Error *Err) : Err(Err) {
1025 // Raise the checked bit if Err is success.
1026 if (Err)
1027 (void)!!*Err;
1028 }
1029
1030 ~ErrorAsOutParameter() {
1031 // Clear the checked bit.
1032 if (Err && !*Err)
1033 *Err = Error::success();
1034 }
1035
1036private:
1037 Error *Err;
1038};
1039
1040/// Helper for Expected<T>s used as out-parameters.
1041///
1042/// See ErrorAsOutParameter.
1043template <typename T>
1044class ExpectedAsOutParameter {
1045public:
1046 ExpectedAsOutParameter(Expected<T> *ValOrErr)
1047 : ValOrErr(ValOrErr) {
1048 if (ValOrErr)
1049 (void)!!*ValOrErr;
1050 }
1051
1052 ~ExpectedAsOutParameter() {
1053 if (ValOrErr)
1054 ValOrErr->setUnchecked();
1055 }
1056
1057private:
1058 Expected<T> *ValOrErr;
1059};
1060
1061/// This class wraps a std::error_code in a Error.
1062///
1063/// This is useful if you're writing an interface that returns a Error
1064/// (or Expected) and you want to call code that still returns
1065/// std::error_codes.
1066class ECError : public ErrorInfo<ECError> {
1067 friend Error errorCodeToError(std::error_code);
1068
1069public:
1070 void setErrorCode(std::error_code EC) { this->EC = EC; }
1071 std::error_code convertToErrorCode() const override { return EC; }
1072 void log(raw_ostream &OS) const override { OS << EC.message(); }
1073
1074 // Used by ErrorInfo::classID.
1075 static char ID;
1076
1077protected:
1078 ECError() = default;
1079 ECError(std::error_code EC) : EC(EC) {}
1080
1081 std::error_code EC;
1082};
1083
1084/// The value returned by this function can be returned from convertToErrorCode
1085/// for Error values where no sensible translation to std::error_code exists.
1086/// It should only be used in this situation, and should never be used where a
1087/// sensible conversion to std::error_code is available, as attempts to convert
1088/// to/from this error will result in a fatal error. (i.e. it is a programmatic
1089///error to try to convert such a value).
1090std::error_code inconvertibleErrorCode();
1091
1092/// Helper for converting an std::error_code to a Error.
1093Error errorCodeToError(std::error_code EC);
1094
1095/// Helper for converting an ECError to a std::error_code.
1096///
1097/// This method requires that Err be Error() or an ECError, otherwise it
1098/// will trigger a call to abort().
1099std::error_code errorToErrorCode(Error Err);
1100
1101/// Convert an ErrorOr<T> to an Expected<T>.
1102template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) {
1103 if (auto EC = EO.getError())
1104 return errorCodeToError(EC);
1105 return std::move(*EO);
1106}
1107
1108/// Convert an Expected<T> to an ErrorOr<T>.
1109template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) {
1110 if (auto Err = E.takeError())
1111 return errorToErrorCode(std::move(Err));
1112 return std::move(*E);
1113}
1114
1115/// This class wraps a string in an Error.
1116///
1117/// StringError is useful in cases where the client is not expected to be able
1118/// to consume the specific error message programmatically (for example, if the
1119/// error message is to be presented to the user).
1120///
1121/// StringError can also be used when additional information is to be printed
1122/// along with a error_code message. Depending on the constructor called, this
1123/// class can either display:
1124/// 1. the error_code message (ECError behavior)
1125/// 2. a string
1126/// 3. the error_code message and a string
1127///
1128/// These behaviors are useful when subtyping is required; for example, when a
1129/// specific library needs an explicit error type. In the example below,
1130/// PDBError is derived from StringError:
1131///
1132/// @code{.cpp}
1133/// Expected<int> foo() {
1134/// return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading,
1135/// "Additional information");
1136/// }
1137/// @endcode
1138///
1139class StringError : public ErrorInfo<StringError> {
1140public:
1141 static char ID;
1142
1143 // Prints EC + S and converts to EC
1144 StringError(std::error_code EC, const Twine &S = Twine());
1145
1146 // Prints S and converts to EC
1147 StringError(const Twine &S, std::error_code EC);
1148
1149 void log(raw_ostream &OS) const override;
1150 std::error_code convertToErrorCode() const override;
1151
1152 const std::string &getMessage() const { return Msg; }
1153
1154private:
1155 std::string Msg;
1156 std::error_code EC;
1157 const bool PrintMsgOnly = false;
1158};
1159
1160/// Create formatted StringError object.
1161template <typename... Ts>
1162Error createStringError(std::error_code EC, char const *Fmt,
1163 const Ts &... Vals) {
1164 std::string Buffer;
1165 raw_string_ostream Stream(Buffer);
1166 Stream << format(Fmt, Vals...);
1167 return make_error<StringError>(Stream.str(), EC);
1168}
1169
1170Error createStringError(std::error_code EC, char const *Msg);
1171
1172/// This class wraps a filename and another Error.
1173///
1174/// In some cases, an error needs to live along a 'source' name, in order to
1175/// show more detailed information to the user.
1176class FileError final : public ErrorInfo<FileError> {
1177
1178 friend Error createFileError(std::string, Error);
1179
1180public:
1181 void log(raw_ostream &OS) const override {
1182 assert(Err && !FileName.empty() && "Trying to log after takeError().")((Err && !FileName.empty() && "Trying to log after takeError()."
) ? static_cast<void> (0) : __assert_fail ("Err && !FileName.empty() && \"Trying to log after takeError().\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 1182, __PRETTY_FUNCTION__))
;
1183 OS << "'" << FileName << "': ";
1184 Err->log(OS);
1185 }
1186
1187 Error takeError() { return Error(std::move(Err)); }
1188
1189 std::error_code convertToErrorCode() const override;
1190
1191 // Used by ErrorInfo::classID.
1192 static char ID;
1193
1194private:
1195 FileError(std::string F, std::unique_ptr<ErrorInfoBase> E) {
1196 assert(E && "Cannot create FileError from Error success value.")((E && "Cannot create FileError from Error success value."
) ? static_cast<void> (0) : __assert_fail ("E && \"Cannot create FileError from Error success value.\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 1196, __PRETTY_FUNCTION__))
;
1197 assert(!F.empty() &&((!F.empty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.empty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 1198, __PRETTY_FUNCTION__))
1198 "The file name provided to FileError must not be empty.")((!F.empty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.empty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/Support/Error.h"
, 1198, __PRETTY_FUNCTION__))
;
1199 FileName = F;
1200 Err = std::move(E);
1201 }
1202
1203 static Error build(std::string F, Error E) {
1204 return Error(std::unique_ptr<FileError>(new FileError(F, E.takePayload())));
1205 }
1206
1207 std::string FileName;
1208 std::unique_ptr<ErrorInfoBase> Err;
1209};
1210
1211/// Concatenate a source file path and/or name with an Error. The resulting
1212/// Error is unchecked.
1213inline Error createFileError(std::string F, Error E) {
1214 return FileError::build(F, std::move(E));
1215}
1216
1217Error createFileError(std::string F, ErrorSuccess) = delete;
1218
1219/// Helper for check-and-exit error handling.
1220///
1221/// For tool use only. NOT FOR USE IN LIBRARY CODE.
1222///
1223class ExitOnError {
1224public:
1225 /// Create an error on exit helper.
1226 ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1)
1227 : Banner(std::move(Banner)),
1228 GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {}
1229
1230 /// Set the banner string for any errors caught by operator().
1231 void setBanner(std::string Banner) { this->Banner = std::move(Banner); }
1232
1233 /// Set the exit-code mapper function.
1234 void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) {
1235 this->GetExitCode = std::move(GetExitCode);
1236 }
1237
1238 /// Check Err. If it's in a failure state log the error(s) and exit.
1239 void operator()(Error Err) const { checkError(std::move(Err)); }
1240
1241 /// Check E. If it's in a success state then return the contained value. If
1242 /// it's in a failure state log the error(s) and exit.
1243 template <typename T> T operator()(Expected<T> &&E) const {
1244 checkError(E.takeError());
1245 return std::move(*E);
1246 }
1247
1248 /// Check E. If it's in a success state then return the contained reference. If
1249 /// it's in a failure state log the error(s) and exit.
1250 template <typename T> T& operator()(Expected<T&> &&E) const {
1251 checkError(E.takeError());
1252 return *E;
1253 }
1254
1255private:
1256 void checkError(Error Err) const {
1257 if (Err) {
1258 int ExitCode = GetExitCode(Err);
1259 logAllUnhandledErrors(std::move(Err), errs(), Banner);
1260 exit(ExitCode);
1261 }
1262 }
1263
1264 std::string Banner;
1265 std::function<int(const Error &)> GetExitCode;
1266};
1267
1268/// Conversion from Error to LLVMErrorRef for C error bindings.
1269inline LLVMErrorRef wrap(Error Err) {
1270 return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release());
1271}
1272
1273/// Conversion from LLVMErrorRef to Error for C error bindings.
1274inline Error unwrap(LLVMErrorRef ErrRef) {
1275 return Error(std::unique_ptr<ErrorInfoBase>(
1276 reinterpret_cast<ErrorInfoBase *>(ErrRef)));
1277}
1278
1279} // end namespace llvm
1280
1281#endif // LLVM_SUPPORT_ERROR_H

/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h

1//===- llvm/ADT/STLExtras.h - Useful STL related functions ------*- C++ -*-===//
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 file contains some templates that are useful if you are working with the
11// STL at all.
12//
13// No library is required when using these functions.
14//
15//===----------------------------------------------------------------------===//
16
17#ifndef LLVM_ADT_STLEXTRAS_H
18#define LLVM_ADT_STLEXTRAS_H
19
20#include "llvm/ADT/Optional.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/ADT/iterator.h"
23#include "llvm/ADT/iterator_range.h"
24#include "llvm/Config/abi-breaking.h"
25#include "llvm/Support/ErrorHandling.h"
26#include <algorithm>
27#include <cassert>
28#include <cstddef>
29#include <cstdint>
30#include <cstdlib>
31#include <functional>
32#include <initializer_list>
33#include <iterator>
34#include <limits>
35#include <memory>
36#include <tuple>
37#include <type_traits>
38#include <utility>
39
40#ifdef EXPENSIVE_CHECKS
41#include <random> // for std::mt19937
42#endif
43
44namespace llvm {
45
46// Only used by compiler if both template types are the same. Useful when
47// using SFINAE to test for the existence of member functions.
48template <typename T, T> struct SameType;
49
50namespace detail {
51
52template <typename RangeT>
53using IterOfRange = decltype(std::begin(std::declval<RangeT &>()));
54
55template <typename RangeT>
56using ValueOfRange = typename std::remove_reference<decltype(
57 *std::begin(std::declval<RangeT &>()))>::type;
58
59} // end namespace detail
60
61//===----------------------------------------------------------------------===//
62// Extra additions to <type_traits>
63//===----------------------------------------------------------------------===//
64
65template <typename T>
66struct negation : std::integral_constant<bool, !bool(T::value)> {};
67
68template <typename...> struct conjunction : std::true_type {};
69template <typename B1> struct conjunction<B1> : B1 {};
70template <typename B1, typename... Bn>
71struct conjunction<B1, Bn...>
72 : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {};
73
74template <typename T> struct make_const_ptr {
75 using type =
76 typename std::add_pointer<typename std::add_const<T>::type>::type;
77};
78//===----------------------------------------------------------------------===//
79// Extra additions to <functional>
80//===----------------------------------------------------------------------===//
81
82template <class Ty> struct identity {
83 using argument_type = Ty;
84
85 Ty &operator()(Ty &self) const {
86 return self;
87 }
88 const Ty &operator()(const Ty &self) const {
89 return self;
90 }
91};
92
93template <class Ty> struct less_ptr {
94 bool operator()(const Ty* left, const Ty* right) const {
95 return *left < *right;
96 }
97};
98
99template <class Ty> struct greater_ptr {
100 bool operator()(const Ty* left, const Ty* right) const {
101 return *right < *left;
102 }
103};
104
105/// An efficient, type-erasing, non-owning reference to a callable. This is
106/// intended for use as the type of a function parameter that is not used
107/// after the function in question returns.
108///
109/// This class does not own the callable, so it is not in general safe to store
110/// a function_ref.
111template<typename Fn> class function_ref;
112
113template<typename Ret, typename ...Params>
114class function_ref<Ret(Params...)> {
115 Ret (*callback)(intptr_t callable, Params ...params) = nullptr;
116 intptr_t callable;
117
118 template<typename Callable>
119 static Ret callback_fn(intptr_t callable, Params ...params) {
120 return (*reinterpret_cast<Callable*>(callable))(
121 std::forward<Params>(params)...);
122 }
123
124public:
125 function_ref() = default;
126 function_ref(std::nullptr_t) {}
127
128 template <typename Callable>
129 function_ref(Callable &&callable,
130 typename std::enable_if<
131 !std::is_same<typename std::remove_reference<Callable>::type,
132 function_ref>::value>::type * = nullptr)
133 : callback(callback_fn<typename std::remove_reference<Callable>::type>),
134 callable(reinterpret_cast<intptr_t>(&callable)) {}
135
136 Ret operator()(Params ...params) const {
137 return callback(callable, std::forward<Params>(params)...);
138 }
139
140 operator bool() const { return callback; }
141};
142
143// deleter - Very very very simple method that is used to invoke operator
144// delete on something. It is used like this:
145//
146// for_each(V.begin(), B.end(), deleter<Interval>);
147template <class T>
148inline void deleter(T *Ptr) {
149 delete Ptr;
150}
151
152//===----------------------------------------------------------------------===//
153// Extra additions to <iterator>
154//===----------------------------------------------------------------------===//
155
156namespace adl_detail {
157
158using std::begin;
159
160template <typename ContainerTy>
161auto adl_begin(ContainerTy &&container)
162 -> decltype(begin(std::forward<ContainerTy>(container))) {
163 return begin(std::forward<ContainerTy>(container));
164}
165
166using std::end;
167
168template <typename ContainerTy>
169auto adl_end(ContainerTy &&container)
170 -> decltype(end(std::forward<ContainerTy>(container))) {
171 return end(std::forward<ContainerTy>(container));
172}
173
174using std::swap;
175
176template <typename T>
177void adl_swap(T &&lhs, T &&rhs) noexcept(noexcept(swap(std::declval<T>(),
178 std::declval<T>()))) {
179 swap(std::forward<T>(lhs), std::forward<T>(rhs));
180}
181
182} // end namespace adl_detail
183
184template <typename ContainerTy>
185auto adl_begin(ContainerTy &&container)
186 -> decltype(adl_detail::adl_begin(std::forward<ContainerTy>(container))) {
187 return adl_detail::adl_begin(std::forward<ContainerTy>(container));
188}
189
190template <typename ContainerTy>
191auto adl_end(ContainerTy &&container)
192 -> decltype(adl_detail::adl_end(std::forward<ContainerTy>(container))) {
193 return adl_detail::adl_end(std::forward<ContainerTy>(container));
194}
195
196template <typename T>
197void adl_swap(T &&lhs, T &&rhs) noexcept(
198 noexcept(adl_detail::adl_swap(std::declval<T>(), std::declval<T>()))) {
199 adl_detail::adl_swap(std::forward<T>(lhs), std::forward<T>(rhs));
200}
201
202/// Test whether \p RangeOrContainer is empty. Similar to C++17 std::empty.
203template <typename T>
204constexpr bool empty(const T &RangeOrContainer) {
205 return adl_begin(RangeOrContainer) == adl_end(RangeOrContainer);
206}
207
208// mapped_iterator - This is a simple iterator adapter that causes a function to
209// be applied whenever operator* is invoked on the iterator.
210
211template <typename ItTy, typename FuncTy,
212 typename FuncReturnTy =
213 decltype(std::declval<FuncTy>()(*std::declval<ItTy>()))>
214class mapped_iterator
215 : public iterator_adaptor_base<
216 mapped_iterator<ItTy, FuncTy>, ItTy,
217 typename std::iterator_traits<ItTy>::iterator_category,
218 typename std::remove_reference<FuncReturnTy>::type> {
219public:
220 mapped_iterator(ItTy U, FuncTy F)
221 : mapped_iterator::iterator_adaptor_base(std::move(U)), F(std::move(F)) {}
222
223 ItTy getCurrent() { return this->I; }
224
225 FuncReturnTy operator*() { return F(*this->I); }
226
227private:
228 FuncTy F;
229};
230
231// map_iterator - Provide a convenient way to create mapped_iterators, just like
232// make_pair is useful for creating pairs...
233template <class ItTy, class FuncTy>
234inline mapped_iterator<ItTy, FuncTy> map_iterator(ItTy I, FuncTy F) {
235 return mapped_iterator<ItTy, FuncTy>(std::move(I), std::move(F));
236}
237
238/// Helper to determine if type T has a member called rbegin().
239template <typename Ty> class has_rbegin_impl {
240 using yes = char[1];
241 using no = char[2];
242
243 template <typename Inner>
244 static yes& test(Inner *I, decltype(I->rbegin()) * = nullptr);
245
246 template <typename>
247 static no& test(...);
248
249public:
250 static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes);
251};
252
253/// Metafunction to determine if T& or T has a member called rbegin().
254template <typename Ty>
255struct has_rbegin : has_rbegin_impl<typename std::remove_reference<Ty>::type> {
256};
257
258// Returns an iterator_range over the given container which iterates in reverse.
259// Note that the container must have rbegin()/rend() methods for this to work.
260template <typename ContainerTy>
261auto reverse(ContainerTy &&C,
262 typename std::enable_if<has_rbegin<ContainerTy>::value>::type * =
263 nullptr) -> decltype(make_range(C.rbegin(), C.rend())) {
264 return make_range(C.rbegin(), C.rend());
265}
266
267// Returns a std::reverse_iterator wrapped around the given iterator.
268template <typename IteratorTy>
269std::reverse_iterator<IteratorTy> make_reverse_iterator(IteratorTy It) {
270 return std::reverse_iterator<IteratorTy>(It);
271}
272
273// Returns an iterator_range over the given container which iterates in reverse.
274// Note that the container must have begin()/end() methods which return
275// bidirectional iterators for this to work.
276template <typename ContainerTy>
277auto reverse(
278 ContainerTy &&C,
279 typename std::enable_if<!has_rbegin<ContainerTy>::value>::type * = nullptr)
280 -> decltype(make_range(llvm::make_reverse_iterator(std::end(C)),
281 llvm::make_reverse_iterator(std::begin(C)))) {
282 return make_range(llvm::make_reverse_iterator(std::end(C)),
283 llvm::make_reverse_iterator(std::begin(C)));
284}
285
286/// An iterator adaptor that filters the elements of given inner iterators.
287///
288/// The predicate parameter should be a callable object that accepts the wrapped
289/// iterator's reference type and returns a bool. When incrementing or
290/// decrementing the iterator, it will call the predicate on each element and
291/// skip any where it returns false.
292///
293/// \code
294/// int A[] = { 1, 2, 3, 4 };
295/// auto R = make_filter_range(A, [](int N) { return N % 2 == 1; });
296/// // R contains { 1, 3 }.
297/// \endcode
298///
299/// Note: filter_iterator_base implements support for forward iteration.
300/// filter_iterator_impl exists to provide support for bidirectional iteration,
301/// conditional on whether the wrapped iterator supports it.
302template <typename WrappedIteratorT, typename PredicateT, typename IterTag>
303class filter_iterator_base
304 : public iterator_adaptor_base<
305 filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
306 WrappedIteratorT,
307 typename std::common_type<
308 IterTag, typename std::iterator_traits<
309 WrappedIteratorT>::iterator_category>::type> {
310 using BaseT = iterator_adaptor_base<
311 filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>,
312 WrappedIteratorT,
313 typename std::common_type<
314 IterTag, typename std::iterator_traits<
315 WrappedIteratorT>::iterator_category>::type>;
316
317protected:
318 WrappedIteratorT End;
319 PredicateT Pred;
320
321 void findNextValid() {
322 while (this->I != End && !Pred(*this->I))
323 BaseT::operator++();
324 }
325
326 // Construct the iterator. The begin iterator needs to know where the end
327 // is, so that it can properly stop when it gets there. The end iterator only
328 // needs the predicate to support bidirectional iteration.
329 filter_iterator_base(WrappedIteratorT Begin, WrappedIteratorT End,
330 PredicateT Pred)
331 : BaseT(Begin), End(End), Pred(Pred) {
332 findNextValid();
333 }
334
335public:
336 using BaseT::operator++;
337
338 filter_iterator_base &operator++() {
339 BaseT::operator++();
340 findNextValid();
341 return *this;
342 }
343};
344
345/// Specialization of filter_iterator_base for forward iteration only.
346template <typename WrappedIteratorT, typename PredicateT,
347 typename IterTag = std::forward_iterator_tag>
348class filter_iterator_impl
349 : public filter_iterator_base<WrappedIteratorT, PredicateT, IterTag> {
350 using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT, IterTag>;
351
352public:
353 filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
354 PredicateT Pred)
355 : BaseT(Begin, End, Pred) {}
356};
357
358/// Specialization of filter_iterator_base for bidirectional iteration.
359template <typename WrappedIteratorT, typename PredicateT>
360class filter_iterator_impl<WrappedIteratorT, PredicateT,
361 std::bidirectional_iterator_tag>
362 : public filter_iterator_base<WrappedIteratorT, PredicateT,
363 std::bidirectional_iterator_tag> {
364 using BaseT = filter_iterator_base<WrappedIteratorT, PredicateT,
365 std::bidirectional_iterator_tag>;
366 void findPrevValid() {
367 while (!this->Pred(*this->I))
368 BaseT::operator--();
369 }
370
371public:
372 using BaseT::operator--;
373
374 filter_iterator_impl(WrappedIteratorT Begin, WrappedIteratorT End,
375 PredicateT Pred)
376 : BaseT(Begin, End, Pred) {}
377
378 filter_iterator_impl &operator--() {
379 BaseT::operator--();
380 findPrevValid();
381 return *this;
382 }
383};
384
385namespace detail {
386
387template <bool is_bidirectional> struct fwd_or_bidi_tag_impl {
388 using type = std::forward_iterator_tag;
389};
390
391template <> struct fwd_or_bidi_tag_impl<true> {
392 using type = std::bidirectional_iterator_tag;
393};
394
395/// Helper which sets its type member to forward_iterator_tag if the category
396/// of \p IterT does not derive from bidirectional_iterator_tag, and to
397/// bidirectional_iterator_tag otherwise.
398template <typename IterT> struct fwd_or_bidi_tag {
399 using type = typename fwd_or_bidi_tag_impl<std::is_base_of<
400 std::bidirectional_iterator_tag,
401 typename std::iterator_traits<IterT>::iterator_category>::value>::type;
402};
403
404} // namespace detail
405
406/// Defines filter_iterator to a suitable specialization of
407/// filter_iterator_impl, based on the underlying iterator's category.
408template <typename WrappedIteratorT, typename PredicateT>
409using filter_iterator = filter_iterator_impl<
410 WrappedIteratorT, PredicateT,
411 typename detail::fwd_or_bidi_tag<WrappedIteratorT>::type>;
412
413/// Convenience function that takes a range of elements and a predicate,
414/// and return a new filter_iterator range.
415///
416/// FIXME: Currently if RangeT && is a rvalue reference to a temporary, the
417/// lifetime of that temporary is not kept by the returned range object, and the
418/// temporary is going to be dropped on the floor after the make_iterator_range
419/// full expression that contains this function call.
420template <typename RangeT, typename PredicateT>
421iterator_range<filter_iterator<detail::IterOfRange<RangeT>, PredicateT>>
422make_filter_range(RangeT &&Range, PredicateT Pred) {
423 using FilterIteratorT =
424 filter_iterator<detail::IterOfRange<RangeT>, PredicateT>;
425 return make_range(
426 FilterIteratorT(std::begin(std::forward<RangeT>(Range)),
427 std::end(std::forward<RangeT>(Range)), Pred),
428 FilterIteratorT(std::end(std::forward<RangeT>(Range)),
429 std::end(std::forward<RangeT>(Range)), Pred));
430}
431
432/// A pseudo-iterator adaptor that is designed to implement "early increment"
433/// style loops.
434///
435/// This is *not a normal iterator* and should almost never be used directly. It
436/// is intended primarily to be used with range based for loops and some range
437/// algorithms.
438///
439/// The iterator isn't quite an `OutputIterator` or an `InputIterator` but
440/// somewhere between them. The constraints of these iterators are:
441///
442/// - On construction or after being incremented, it is comparable and
443/// dereferencable. It is *not* incrementable.
444/// - After being dereferenced, it is neither comparable nor dereferencable, it
445/// is only incrementable.
446///
447/// This means you can only dereference the iterator once, and you can only
448/// increment it once between dereferences.
449template <typename WrappedIteratorT>
450class early_inc_iterator_impl
451 : public iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>,
452 WrappedIteratorT, std::input_iterator_tag> {
453 using BaseT =
454 iterator_adaptor_base<early_inc_iterator_impl<WrappedIteratorT>,
455 WrappedIteratorT, std::input_iterator_tag>;
456
457 using PointerT = typename std::iterator_traits<WrappedIteratorT>::pointer;
458
459protected:
460#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
461 bool IsEarlyIncremented = false;
462#endif
463
464public:
465 early_inc_iterator_impl(WrappedIteratorT I) : BaseT(I) {}
466
467 using BaseT::operator*;
468 typename BaseT::reference operator*() {
469#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
470 assert(!IsEarlyIncremented && "Cannot dereference twice!")((!IsEarlyIncremented && "Cannot dereference twice!")
? static_cast<void> (0) : __assert_fail ("!IsEarlyIncremented && \"Cannot dereference twice!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 470, __PRETTY_FUNCTION__))
;
471 IsEarlyIncremented = true;
472#endif
473 return *(this->I)++;
474 }
475
476 using BaseT::operator++;
477 early_inc_iterator_impl &operator++() {
478#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
479 assert(IsEarlyIncremented && "Cannot increment before dereferencing!")((IsEarlyIncremented && "Cannot increment before dereferencing!"
) ? static_cast<void> (0) : __assert_fail ("IsEarlyIncremented && \"Cannot increment before dereferencing!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 479, __PRETTY_FUNCTION__))
;
480 IsEarlyIncremented = false;
481#endif
482 return *this;
483 }
484
485 using BaseT::operator==;
486 bool operator==(const early_inc_iterator_impl &RHS) const {
487#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
488 assert(!IsEarlyIncremented && "Cannot compare after dereferencing!")((!IsEarlyIncremented && "Cannot compare after dereferencing!"
) ? static_cast<void> (0) : __assert_fail ("!IsEarlyIncremented && \"Cannot compare after dereferencing!\""
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 488, __PRETTY_FUNCTION__))
;
489#endif
490 return BaseT::operator==(RHS);
491 }
492};
493
494/// Make a range that does early increment to allow mutation of the underlying
495/// range without disrupting iteration.
496///
497/// The underlying iterator will be incremented immediately after it is
498/// dereferenced, allowing deletion of the current node or insertion of nodes to
499/// not disrupt iteration provided they do not invalidate the *next* iterator --
500/// the current iterator can be invalidated.
501///
502/// This requires a very exact pattern of use that is only really suitable to
503/// range based for loops and other range algorithms that explicitly guarantee
504/// to dereference exactly once each element, and to increment exactly once each
505/// element.
506template <typename RangeT>
507iterator_range<early_inc_iterator_impl<detail::IterOfRange<RangeT>>>
508make_early_inc_range(RangeT &&Range) {
509 using EarlyIncIteratorT =
510 early_inc_iterator_impl<detail::IterOfRange<RangeT>>;
511 return make_range(EarlyIncIteratorT(std::begin(std::forward<RangeT>(Range))),
512 EarlyIncIteratorT(std::end(std::forward<RangeT>(Range))));
513}
514
515// forward declarations required by zip_shortest/zip_first/zip_longest
516template <typename R, typename UnaryPredicate>
517bool all_of(R &&range, UnaryPredicate P);
518template <typename R, typename UnaryPredicate>
519bool any_of(R &&range, UnaryPredicate P);
520
521template <size_t... I> struct index_sequence;
522
523template <class... Ts> struct index_sequence_for;
524
525namespace detail {
526
527using std::declval;
528
529// We have to alias this since inlining the actual type at the usage site
530// in the parameter list of iterator_facade_base<> below ICEs MSVC 2017.
531template<typename... Iters> struct ZipTupleType {
532 using type = std::tuple<decltype(*declval<Iters>())...>;
533};
534
535template <typename ZipType, typename... Iters>
536using zip_traits = iterator_facade_base<
537 ZipType, typename std::common_type<std::bidirectional_iterator_tag,
538 typename std::iterator_traits<
539 Iters>::iterator_category...>::type,
540 // ^ TODO: Implement random access methods.
541 typename ZipTupleType<Iters...>::type,
542 typename std::iterator_traits<typename std::tuple_element<
543 0, std::tuple<Iters...>>::type>::difference_type,
544 // ^ FIXME: This follows boost::make_zip_iterator's assumption that all
545 // inner iterators have the same difference_type. It would fail if, for
546 // instance, the second field's difference_type were non-numeric while the
547 // first is.
548 typename ZipTupleType<Iters...>::type *,
549 typename ZipTupleType<Iters...>::type>;
550
551template <typename ZipType, typename... Iters>
552struct zip_common : public zip_traits<ZipType, Iters...> {
553 using Base = zip_traits<ZipType, Iters...>;
554 using value_type = typename Base::value_type;
555
556 std::tuple<Iters...> iterators;
557
558protected:
559 template <size_t... Ns> value_type deref(index_sequence<Ns...>) const {
560 return value_type(*std::get<Ns>(iterators)...);
561 }
562
563 template <size_t... Ns>
564 decltype(iterators) tup_inc(index_sequence<Ns...>) const {
565 return std::tuple<Iters...>(std::next(std::get<Ns>(iterators))...);
566 }
567
568 template <size_t... Ns>
569 decltype(iterators) tup_dec(index_sequence<Ns...>) const {
570 return std::tuple<Iters...>(std::prev(std::get<Ns>(iterators))...);
571 }
572
573public:
574 zip_common(Iters &&... ts) : iterators(std::forward<Iters>(ts)...) {}
575
576 value_type operator*() { return deref(index_sequence_for<Iters...>{}); }
577
578 const value_type operator*() const {
579 return deref(index_sequence_for<Iters...>{});
580 }
581
582 ZipType &operator++() {
583 iterators = tup_inc(index_sequence_for<Iters...>{});
584 return *reinterpret_cast<ZipType *>(this);
585 }
586
587 ZipType &operator--() {
588 static_assert(Base::IsBidirectional,
589 "All inner iterators must be at least bidirectional.");
590 iterators = tup_dec(index_sequence_for<Iters...>{});
591 return *reinterpret_cast<ZipType *>(this);
592 }
593};
594
595template <typename... Iters>
596struct zip_first : public zip_common<zip_first<Iters...>, Iters...> {
597 using Base = zip_common<zip_first<Iters...>, Iters...>;
598
599 bool operator==(const zip_first<Iters...> &other) const {
600 return std::get<0>(this->iterators) == std::get<0>(other.iterators);
601 }
602
603 zip_first(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
604};
605
606template <typename... Iters>
607class zip_shortest : public zip_common<zip_shortest<Iters...>, Iters...> {
608 template <size_t... Ns>
609 bool test(const zip_shortest<Iters...> &other, index_sequence<Ns...>) const {
610 return all_of(std::initializer_list<bool>{std::get<Ns>(this->iterators) !=
611 std::get<Ns>(other.iterators)...},
612 identity<bool>{});
613 }
614
615public:
616 using Base = zip_common<zip_shortest<Iters...>, Iters...>;
617
618 zip_shortest(Iters &&... ts) : Base(std::forward<Iters>(ts)...) {}
619
620 bool operator==(const zip_shortest<Iters...> &other) const {
621 return !test(other, index_sequence_for<Iters...>{});
622 }
623};
624
625template <template <typename...> class ItType, typename... Args> class zippy {
626public:
627 using iterator = ItType<decltype(std::begin(std::declval<Args>()))...>;
628 using iterator_category = typename iterator::iterator_category;
629 using value_type = typename iterator::value_type;
630 using difference_type = typename iterator::difference_type;
631 using pointer = typename iterator::pointer;
632 using reference = typename iterator::reference;
633
634private:
635 std::tuple<Args...> ts;
636
637 template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) const {
638 return iterator(std::begin(std::get<Ns>(ts))...);
639 }
640 template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) const {
641 return iterator(std::end(std::get<Ns>(ts))...);
642 }
643
644public:
645 zippy(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {}
646
647 iterator begin() const { return begin_impl(index_sequence_for<Args...>{}); }
648 iterator end() const { return end_impl(index_sequence_for<Args...>{}); }
649};
650
651} // end namespace detail
652
653/// zip iterator for two or more iteratable types.
654template <typename T, typename U, typename... Args>
655detail::zippy<detail::zip_shortest, T, U, Args...> zip(T &&t, U &&u,
656 Args &&... args) {
657 return detail::zippy<detail::zip_shortest, T, U, Args...>(
658 std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
659}
660
661/// zip iterator that, for the sake of efficiency, assumes the first iteratee to
662/// be the shortest.
663template <typename T, typename U, typename... Args>
664detail::zippy<detail::zip_first, T, U, Args...> zip_first(T &&t, U &&u,
665 Args &&... args) {
666 return detail::zippy<detail::zip_first, T, U, Args...>(
667 std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
668}
669
670namespace detail {
671template <typename Iter>
672static Iter next_or_end(const Iter &I, const Iter &End) {
673 if (I == End)
674 return End;
675 return std::next(I);
676}
677
678template <typename Iter>
679static auto deref_or_none(const Iter &I, const Iter &End)
680 -> llvm::Optional<typename std::remove_const<
681 typename std::remove_reference<decltype(*I)>::type>::type> {
682 if (I == End)
683 return None;
684 return *I;
685}
686
687template <typename Iter> struct ZipLongestItemType {
688 using type =
689 llvm::Optional<typename std::remove_const<typename std::remove_reference<
690 decltype(*std::declval<Iter>())>::type>::type>;
691};
692
693template <typename... Iters> struct ZipLongestTupleType {
694 using type = std::tuple<typename ZipLongestItemType<Iters>::type...>;
695};
696
697template <typename... Iters>
698class zip_longest_iterator
699 : public iterator_facade_base<
700 zip_longest_iterator<Iters...>,
701 typename std::common_type<
702 std::forward_iterator_tag,
703 typename std::iterator_traits<Iters>::iterator_category...>::type,
704 typename ZipLongestTupleType<Iters...>::type,
705 typename std::iterator_traits<typename std::tuple_element<
706 0, std::tuple<Iters...>>::type>::difference_type,
707 typename ZipLongestTupleType<Iters...>::type *,
708 typename ZipLongestTupleType<Iters...>::type> {
709public:
710 using value_type = typename ZipLongestTupleType<Iters...>::type;
711
712private:
713 std::tuple<Iters...> iterators;
714 std::tuple<Iters...> end_iterators;
715
716 template <size_t... Ns>
717 bool test(const zip_longest_iterator<Iters...> &other,
718 index_sequence<Ns...>) const {
719 return llvm::any_of(
720 std::initializer_list<bool>{std::get<Ns>(this->iterators) !=
721 std::get<Ns>(other.iterators)...},
722 identity<bool>{});
723 }
724
725 template <size_t... Ns> value_type deref(index_sequence<Ns...>) const {
726 return value_type(
727 deref_or_none(std::get<Ns>(iterators), std::get<Ns>(end_iterators))...);
728 }
729
730 template <size_t... Ns>
731 decltype(iterators) tup_inc(index_sequence<Ns...>) const {
732 return std::tuple<Iters...>(
733 next_or_end(std::get<Ns>(iterators), std::get<Ns>(end_iterators))...);
734 }
735
736public:
737 zip_longest_iterator(std::pair<Iters &&, Iters &&>... ts)
738 : iterators(std::forward<Iters>(ts.first)...),
739 end_iterators(std::forward<Iters>(ts.second)...) {}
740
741 value_type operator*() { return deref(index_sequence_for<Iters...>{}); }
742
743 value_type operator*() const { return deref(index_sequence_for<Iters...>{}); }
744
745 zip_longest_iterator<Iters...> &operator++() {
746 iterators = tup_inc(index_sequence_for<Iters...>{});
747 return *this;
748 }
749
750 bool operator==(const zip_longest_iterator<Iters...> &other) const {
751 return !test(other, index_sequence_for<Iters...>{});
752 }
753};
754
755template <typename... Args> class zip_longest_range {
756public:
757 using iterator =
758 zip_longest_iterator<decltype(adl_begin(std::declval<Args>()))...>;
759 using iterator_category = typename iterator::iterator_category;
760 using value_type = typename iterator::value_type;
761 using difference_type = typename iterator::difference_type;
762 using pointer = typename iterator::pointer;
763 using reference = typename iterator::reference;
764
765private:
766 std::tuple<Args...> ts;
767
768 template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) const {
769 return iterator(std::make_pair(adl_begin(std::get<Ns>(ts)),
770 adl_end(std::get<Ns>(ts)))...);
771 }
772
773 template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) const {
774 return iterator(std::make_pair(adl_end(std::get<Ns>(ts)),
775 adl_end(std::get<Ns>(ts)))...);
776 }
777
778public:
779 zip_longest_range(Args &&... ts_) : ts(std::forward<Args>(ts_)...) {}
780
781 iterator begin() const { return begin_impl(index_sequence_for<Args...>{}); }
782 iterator end() const { return end_impl(index_sequence_for<Args...>{}); }
783};
784} // namespace detail
785
786/// Iterate over two or more iterators at the same time. Iteration continues
787/// until all iterators reach the end. The llvm::Optional only contains a value
788/// if the iterator has not reached the end.
789template <typename T, typename U, typename... Args>
790detail::zip_longest_range<T, U, Args...> zip_longest(T &&t, U &&u,
791 Args &&... args) {
792 return detail::zip_longest_range<T, U, Args...>(
793 std::forward<T>(t), std::forward<U>(u), std::forward<Args>(args)...);
794}
795
796/// Iterator wrapper that concatenates sequences together.
797///
798/// This can concatenate different iterators, even with different types, into
799/// a single iterator provided the value types of all the concatenated
800/// iterators expose `reference` and `pointer` types that can be converted to
801/// `ValueT &` and `ValueT *` respectively. It doesn't support more
802/// interesting/customized pointer or reference types.
803///
804/// Currently this only supports forward or higher iterator categories as
805/// inputs and always exposes a forward iterator interface.
806template <typename ValueT, typename... IterTs>
807class concat_iterator
808 : public iterator_facade_base<concat_iterator<ValueT, IterTs...>,
809 std::forward_iterator_tag, ValueT> {
810 using BaseT = typename concat_iterator::iterator_facade_base;
811
812 /// We store both the current and end iterators for each concatenated
813 /// sequence in a tuple of pairs.
814 ///
815 /// Note that something like iterator_range seems nice at first here, but the
816 /// range properties are of little benefit and end up getting in the way
817 /// because we need to do mutation on the current iterators.
818 std::tuple<IterTs...> Begins;
819 std::tuple<IterTs...> Ends;
820
821 /// Attempts to increment a specific iterator.
822 ///
823 /// Returns true if it was able to increment the iterator. Returns false if
824 /// the iterator is already at the end iterator.
825 template <size_t Index> bool incrementHelper() {
826 auto &Begin = std::get<Index>(Begins);
827 auto &End = std::get<Index>(Ends);
828 if (Begin == End)
829 return false;
830
831 ++Begin;
832 return true;
833 }
834
835 /// Increments the first non-end iterator.
836 ///
837 /// It is an error to call this with all iterators at the end.
838 template <size_t... Ns> void increment(index_sequence<Ns...>) {
839 // Build a sequence of functions to increment each iterator if possible.
840 bool (concat_iterator::*IncrementHelperFns[])() = {
841 &concat_iterator::incrementHelper<Ns>...};
842
843 // Loop over them, and stop as soon as we succeed at incrementing one.
844 for (auto &IncrementHelperFn : IncrementHelperFns)
845 if ((this->*IncrementHelperFn)())
846 return;
847
848 llvm_unreachable("Attempted to increment an end concat iterator!")::llvm::llvm_unreachable_internal("Attempted to increment an end concat iterator!"
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 848)
;
849 }
850
851 /// Returns null if the specified iterator is at the end. Otherwise,
852 /// dereferences the iterator and returns the address of the resulting
853 /// reference.
854 template <size_t Index> ValueT *getHelper() const {
855 auto &Begin = std::get<Index>(Begins);
856 auto &End = std::get<Index>(Ends);
857 if (Begin == End)
858 return nullptr;
859
860 return &*Begin;
861 }
862
863 /// Finds the first non-end iterator, dereferences, and returns the resulting
864 /// reference.
865 ///
866 /// It is an error to call this with all iterators at the end.
867 template <size_t... Ns> ValueT &get(index_sequence<Ns...>) const {
868 // Build a sequence of functions to get from iterator if possible.
869 ValueT *(concat_iterator::*GetHelperFns[])() const = {
870 &concat_iterator::getHelper<Ns>...};
871
872 // Loop over them, and return the first result we find.
873 for (auto &GetHelperFn : GetHelperFns)
874 if (ValueT *P = (this->*GetHelperFn)())
875 return *P;
876
877 llvm_unreachable("Attempted to get a pointer from an end concat iterator!")::llvm::llvm_unreachable_internal("Attempted to get a pointer from an end concat iterator!"
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 877)
;
878 }
879
880public:
881 /// Constructs an iterator from a squence of ranges.
882 ///
883 /// We need the full range to know how to switch between each of the
884 /// iterators.
885 template <typename... RangeTs>
886 explicit concat_iterator(RangeTs &&... Ranges)
887 : Begins(std::begin(Ranges)...), Ends(std::end(Ranges)...) {}
888
889 using BaseT::operator++;
890
891 concat_iterator &operator++() {
892 increment(index_sequence_for<IterTs...>());
893 return *this;
894 }
895
896 ValueT &operator*() const { return get(index_sequence_for<IterTs...>()); }
897
898 bool operator==(const concat_iterator &RHS) const {
899 return Begins == RHS.Begins && Ends == RHS.Ends;
900 }
901};
902
903namespace detail {
904
905/// Helper to store a sequence of ranges being concatenated and access them.
906///
907/// This is designed to facilitate providing actual storage when temporaries
908/// are passed into the constructor such that we can use it as part of range
909/// based for loops.
910template <typename ValueT, typename... RangeTs> class concat_range {
911public:
912 using iterator =
913 concat_iterator<ValueT,
914 decltype(std::begin(std::declval<RangeTs &>()))...>;
915
916private:
917 std::tuple<RangeTs...> Ranges;
918
919 template <size_t... Ns> iterator begin_impl(index_sequence<Ns...>) {
920 return iterator(std::get<Ns>(Ranges)...);
921 }
922 template <size_t... Ns> iterator end_impl(index_sequence<Ns...>) {
923 return iterator(make_range(std::end(std::get<Ns>(Ranges)),
924 std::end(std::get<Ns>(Ranges)))...);
925 }
926
927public:
928 concat_range(RangeTs &&... Ranges)
929 : Ranges(std::forward<RangeTs>(Ranges)...) {}
930
931 iterator begin() { return begin_impl(index_sequence_for<RangeTs...>{}); }
932 iterator end() { return end_impl(index_sequence_for<RangeTs...>{}); }
933};
934
935} // end namespace detail
936
937/// Concatenated range across two or more ranges.
938///
939/// The desired value type must be explicitly specified.
940template <typename ValueT, typename... RangeTs>
941detail::concat_range<ValueT, RangeTs...> concat(RangeTs &&... Ranges) {
942 static_assert(sizeof...(RangeTs) > 1,
943 "Need more than one range to concatenate!");
944 return detail::concat_range<ValueT, RangeTs...>(
945 std::forward<RangeTs>(Ranges)...);
946}
947
948//===----------------------------------------------------------------------===//
949// Extra additions to <utility>
950//===----------------------------------------------------------------------===//
951
952/// Function object to check whether the first component of a std::pair
953/// compares less than the first component of another std::pair.
954struct less_first {
955 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
956 return lhs.first < rhs.first;
957 }
958};
959
960/// Function object to check whether the second component of a std::pair
961/// compares less than the second component of another std::pair.
962struct less_second {
963 template <typename T> bool operator()(const T &lhs, const T &rhs) const {
964 return lhs.second < rhs.second;
965 }
966};
967
968/// \brief Function object to apply a binary function to the first component of
969/// a std::pair.
970template<typename FuncTy>
971struct on_first {
972 FuncTy func;
973
974 template <typename T>
975 auto operator()(const T &lhs, const T &rhs) const
976 -> decltype(func(lhs.first, rhs.first)) {
977 return func(lhs.first, rhs.first);
978 }
979};
980
981// A subset of N3658. More stuff can be added as-needed.
982
983/// Represents a compile-time sequence of integers.
984template <class T, T... I> struct integer_sequence {
985 using value_type = T;
986
987 static constexpr size_t size() { return sizeof...(I); }
988};
989
990/// Alias for the common case of a sequence of size_ts.
991template <size_t... I>
992struct index_sequence : integer_sequence<std::size_t, I...> {};
993
994template <std::size_t N, std::size_t... I>
995struct build_index_impl : build_index_impl<N - 1, N - 1, I...> {};
996template <std::size_t... I>
997struct build_index_impl<0, I...> : index_sequence<I...> {};
998
999/// Creates a compile-time integer sequence for a parameter pack.
1000template <class... Ts>
1001struct index_sequence_for : build_index_impl<sizeof...(Ts)> {};
1002
1003/// Utility type to build an inheritance chain that makes it easy to rank
1004/// overload candidates.
1005template <int N> struct rank : rank<N - 1> {};
1006template <> struct rank<0> {};
1007
1008/// traits class for checking whether type T is one of any of the given
1009/// types in the variadic list.
1010template <typename T, typename... Ts> struct is_one_of {
1011 static const bool value = false;
1012};
1013
1014template <typename T, typename U, typename... Ts>
1015struct is_one_of<T, U, Ts...> {
1016 static const bool value =
1017 std::is_same<T, U>::value || is_one_of<T, Ts...>::value;
1018};
1019
1020/// traits class for checking whether type T is a base class for all
1021/// the given types in the variadic list.
1022template <typename T, typename... Ts> struct are_base_of {
1023 static const bool value = true;
1024};
1025
1026template <typename T, typename U, typename... Ts>
1027struct are_base_of<T, U, Ts...> {
1028 static const bool value =
1029 std::is_base_of<T, U>::value && are_base_of<T, Ts...>::value;
1030};
1031
1032//===----------------------------------------------------------------------===//
1033// Extra additions for arrays
1034//===----------------------------------------------------------------------===//
1035
1036/// Find the length of an array.
1037template <class T, std::size_t N>
1038constexpr inline size_t array_lengthof(T (&)[N]) {
1039 return N;
1040}
1041
1042/// Adapt std::less<T> for array_pod_sort.
1043template<typename T>
1044inline int array_pod_sort_comparator(const void *P1, const void *P2) {
1045 if (std::less<T>()(*reinterpret_cast<const T*>(P1),
1046 *reinterpret_cast<const T*>(P2)))
1047 return -1;
1048 if (std::less<T>()(*reinterpret_cast<const T*>(P2),
1049 *reinterpret_cast<const T*>(P1)))
1050 return 1;
1051 return 0;
1052}
1053
1054/// get_array_pod_sort_comparator - This is an internal helper function used to
1055/// get type deduction of T right.
1056template<typename T>
1057inline int (*get_array_pod_sort_comparator(const T &))
1058 (const void*, const void*) {
1059 return array_pod_sort_comparator<T>;
1060}
1061
1062/// array_pod_sort - This sorts an array with the specified start and end
1063/// extent. This is just like std::sort, except that it calls qsort instead of
1064/// using an inlined template. qsort is slightly slower than std::sort, but
1065/// most sorts are not performance critical in LLVM and std::sort has to be
1066/// template instantiated for each type, leading to significant measured code
1067/// bloat. This function should generally be used instead of std::sort where
1068/// possible.
1069///
1070/// This function assumes that you have simple POD-like types that can be
1071/// compared with std::less and can be moved with memcpy. If this isn't true,
1072/// you should use std::sort.
1073///
1074/// NOTE: If qsort_r were portable, we could allow a custom comparator and
1075/// default to std::less.
1076template<class IteratorTy>
1077inline void array_pod_sort(IteratorTy Start, IteratorTy End) {
1078 // Don't inefficiently call qsort with one element or trigger undefined
1079 // behavior with an empty sequence.
1080 auto NElts = End - Start;
1081 if (NElts <= 1) return;
1082#ifdef EXPENSIVE_CHECKS
1083 std::mt19937 Generator(std::random_device{}());
1084 std::shuffle(Start, End, Generator);
1085#endif
1086 qsort(&*Start, NElts, sizeof(*Start), get_array_pod_sort_comparator(*Start));
1087}
1088
1089template <class IteratorTy>
1090inline void array_pod_sort(
1091 IteratorTy Start, IteratorTy End,
1092 int (*Compare)(
1093 const typename std::iterator_traits<IteratorTy>::value_type *,
1094 const typename std::iterator_traits<IteratorTy>::value_type *)) {
1095 // Don't inefficiently call qsort with one element or trigger undefined
1096 // behavior with an empty sequence.
1097 auto NElts = End - Start;
1098 if (NElts <= 1) return;
1099#ifdef EXPENSIVE_CHECKS
1100 std::mt19937 Generator(std::random_device{}());
1101 std::shuffle(Start, End, Generator);
1102#endif
1103 qsort(&*Start, NElts, sizeof(*Start),
1104 reinterpret_cast<int (*)(const void *, const void *)>(Compare));
1105}
1106
1107// Provide wrappers to std::sort which shuffle the elements before sorting
1108// to help uncover non-deterministic behavior (PR35135).
1109template <typename IteratorTy>
1110inline void sort(IteratorTy Start, IteratorTy End) {
1111#ifdef EXPENSIVE_CHECKS
1112 std::mt19937 Generator(std::random_device{}());
1113 std::shuffle(Start, End, Generator);
1114#endif
1115 std::sort(Start, End);
1116}
1117
1118template <typename Container> inline void sort(Container &&C) {
1119 llvm::sort(adl_begin(C), adl_end(C));
1120}
1121
1122template <typename IteratorTy, typename Compare>
1123inline void sort(IteratorTy Start, IteratorTy End, Compare Comp) {
1124#ifdef EXPENSIVE_CHECKS
1125 std::mt19937 Generator(std::random_device{}());
1126 std::shuffle(Start, End, Generator);
1127#endif
1128 std::sort(Start, End, Comp);
1129}
1130
1131template <typename Container, typename Compare>
1132inline void sort(Container &&C, Compare Comp) {
1133 llvm::sort(adl_begin(C), adl_end(C), Comp);
1134}
1135
1136//===----------------------------------------------------------------------===//
1137// Extra additions to <algorithm>
1138//===----------------------------------------------------------------------===//
1139
1140/// For a container of pointers, deletes the pointers and then clears the
1141/// container.
1142template<typename Container>
1143void DeleteContainerPointers(Container &C) {
1144 for (auto V : C)
1145 delete V;
1146 C.clear();
1147}
1148
1149/// In a container of pairs (usually a map) whose second element is a pointer,
1150/// deletes the second elements and then clears the container.
1151template<typename Container>
1152void DeleteContainerSeconds(Container &C) {
1153 for (auto &V : C)
1154 delete V.second;
1155 C.clear();
1156}
1157
1158/// Get the size of a range. This is a wrapper function around std::distance
1159/// which is only enabled when the operation is O(1).
1160template <typename R>
1161auto size(R &&Range, typename std::enable_if<
1162 std::is_same<typename std::iterator_traits<decltype(
1163 Range.begin())>::iterator_category,
1164 std::random_access_iterator_tag>::value,
1165 void>::type * = nullptr)
1166 -> decltype(std::distance(Range.begin(), Range.end())) {
1167 return std::distance(Range.begin(), Range.end());
1168}
1169
1170/// Provide wrappers to std::for_each which take ranges instead of having to
1171/// pass begin/end explicitly.
1172template <typename R, typename UnaryPredicate>
1173UnaryPredicate for_each(R &&Range, UnaryPredicate P) {
1174 return std::for_each(adl_begin(Range), adl_end(Range), P);
1175}
1176
1177/// Provide wrappers to std::all_of which take ranges instead of having to pass
1178/// begin/end explicitly.
1179template <typename R, typename UnaryPredicate>
1180bool all_of(R &&Range, UnaryPredicate P) {
1181 return std::all_of(adl_begin(Range), adl_end(Range), P);
1182}
1183
1184/// Provide wrappers to std::any_of which take ranges instead of having to pass
1185/// begin/end explicitly.
1186template <typename R, typename UnaryPredicate>
1187bool any_of(R &&Range, UnaryPredicate P) {
1188 return std::any_of(adl_begin(Range), adl_end(Range), P);
1189}
1190
1191/// Provide wrappers to std::none_of which take ranges instead of having to pass
1192/// begin/end explicitly.
1193template <typename R, typename UnaryPredicate>
1194bool none_of(R &&Range, UnaryPredicate P) {
1195 return std::none_of(adl_begin(Range), adl_end(Range), P);
1196}
1197
1198/// Provide wrappers to std::find which take ranges instead of having to pass
1199/// begin/end explicitly.
1200template <typename R, typename T>
1201auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range)) {
1202 return std::find(adl_begin(Range), adl_end(Range), Val);
1203}
1204
1205/// Provide wrappers to std::find_if which take ranges instead of having to pass
1206/// begin/end explicitly.
1207template <typename R, typename UnaryPredicate>
1208auto find_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1209 return std::find_if(adl_begin(Range), adl_end(Range), P);
1210}
1211
1212template <typename R, typename UnaryPredicate>
1213auto find_if_not(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1214 return std::find_if_not(adl_begin(Range), adl_end(Range), P);
1215}
1216
1217/// Provide wrappers to std::remove_if which take ranges instead of having to
1218/// pass begin/end explicitly.
1219template <typename R, typename UnaryPredicate>
1220auto remove_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1221 return std::remove_if(adl_begin(Range), adl_end(Range), P);
1222}
1223
1224/// Provide wrappers to std::copy_if which take ranges instead of having to
1225/// pass begin/end explicitly.
1226template <typename R, typename OutputIt, typename UnaryPredicate>
1227OutputIt copy_if(R &&Range, OutputIt Out, UnaryPredicate P) {
1228 return std::copy_if(adl_begin(Range), adl_end(Range), Out, P);
1229}
1230
1231template <typename R, typename OutputIt>
1232OutputIt copy(R &&Range, OutputIt Out) {
1233 return std::copy(adl_begin(Range), adl_end(Range), Out);
1234}
1235
1236/// Wrapper function around std::find to detect if an element exists
1237/// in a container.
1238template <typename R, typename E>
1239bool is_contained(R &&Range, const E &Element) {
1240 return std::find(adl_begin(Range), adl_end(Range), Element) != adl_end(Range);
1241}
1242
1243/// Wrapper function around std::count to count the number of times an element
1244/// \p Element occurs in the given range \p Range.
1245template <typename R, typename E>
1246auto count(R &&Range, const E &Element) ->
1247 typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
1248 return std::count(adl_begin(Range), adl_end(Range), Element);
1249}
1250
1251/// Wrapper function around std::count_if to count the number of times an
1252/// element satisfying a given predicate occurs in a range.
1253template <typename R, typename UnaryPredicate>
1254auto count_if(R &&Range, UnaryPredicate P) ->
1255 typename std::iterator_traits<decltype(adl_begin(Range))>::difference_type {
1256 return std::count_if(adl_begin(Range), adl_end(Range), P);
1257}
1258
1259/// Wrapper function around std::transform to apply a function to a range and
1260/// store the result elsewhere.
1261template <typename R, typename OutputIt, typename UnaryPredicate>
1262OutputIt transform(R &&Range, OutputIt d_first, UnaryPredicate P) {
1263 return std::transform(adl_begin(Range), adl_end(Range), d_first, P);
1264}
1265
1266/// Provide wrappers to std::partition which take ranges instead of having to
1267/// pass begin/end explicitly.
1268template <typename R, typename UnaryPredicate>
1269auto partition(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range)) {
1270 return std::partition(adl_begin(Range), adl_end(Range), P);
1271}
1272
1273/// Provide wrappers to std::lower_bound which take ranges instead of having to
1274/// pass begin/end explicitly.
1275template <typename R, typename ForwardIt>
1276auto lower_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range)) {
1277 return std::lower_bound(adl_begin(Range), adl_end(Range), I);
1278}
1279
1280template <typename R, typename ForwardIt, typename Compare>
1281auto lower_bound(R &&Range, ForwardIt I, Compare C)
1282 -> decltype(adl_begin(Range)) {
1283 return std::lower_bound(adl_begin(Range), adl_end(Range), I, C);
1284}
1285
1286/// Provide wrappers to std::upper_bound which take ranges instead of having to
1287/// pass begin/end explicitly.
1288template <typename R, typename ForwardIt>
1289auto upper_bound(R &&Range, ForwardIt I) -> decltype(adl_begin(Range)) {
1290 return std::upper_bound(adl_begin(Range), adl_end(Range), I);
1291}
1292
1293template <typename R, typename ForwardIt, typename Compare>
1294auto upper_bound(R &&Range, ForwardIt I, Compare C)
1295 -> decltype(adl_begin(Range)) {
1296 return std::upper_bound(adl_begin(Range), adl_end(Range), I, C);
1297}
1298/// Wrapper function around std::equal to detect if all elements
1299/// in a container are same.
1300template <typename R>
1301bool is_splat(R &&Range) {
1302 size_t range_size = size(Range);
1303 return range_size != 0 && (range_size == 1 ||
1304 std::equal(adl_begin(Range) + 1, adl_end(Range), adl_begin(Range)));
1305}
1306
1307/// Given a range of type R, iterate the entire range and return a
1308/// SmallVector with elements of the vector. This is useful, for example,
1309/// when you want to iterate a range and then sort the results.
1310template <unsigned Size, typename R>
1311SmallVector<typename std::remove_const<detail::ValueOfRange<R>>::type, Size>
1312to_vector(R &&Range) {
1313 return {adl_begin(Range), adl_end(Range)};
1314}
1315
1316/// Provide a container algorithm similar to C++ Library Fundamentals v2's
1317/// `erase_if` which is equivalent to:
1318///
1319/// C.erase(remove_if(C, pred), C.end());
1320///
1321/// This version works for any container with an erase method call accepting
1322/// two iterators.
1323template <typename Container, typename UnaryPredicate>
1324void erase_if(Container &C, UnaryPredicate P) {
1325 C.erase(remove_if(C, P), C.end());
1326}
1327
1328//===----------------------------------------------------------------------===//
1329// Extra additions to <memory>
1330//===----------------------------------------------------------------------===//
1331
1332// Implement make_unique according to N3656.
1333
1334/// Constructs a `new T()` with the given args and returns a
1335/// `unique_ptr<T>` which owns the object.
1336///
1337/// Example:
1338///
1339/// auto p = make_unique<int>();
1340/// auto p = make_unique<std::tuple<int, int>>(0, 1);
1341template <class T, class... Args>
1342typename std::enable_if<!std::is_array<T>::value, std::unique_ptr<T>>::type
1343make_unique(Args &&... args) {
1344 return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
9
Memory is allocated
1345}
1346
1347/// Constructs a `new T[n]` with the given args and returns a
1348/// `unique_ptr<T[]>` which owns the object.
1349///
1350/// \param n size of the new array.
1351///
1352/// Example:
1353///
1354/// auto p = make_unique<int[]>(2); // value-initializes the array with 0's.
1355template <class T>
1356typename std::enable_if<std::is_array<T>::value && std::extent<T>::value == 0,
1357 std::unique_ptr<T>>::type
1358make_unique(size_t n) {
1359 return std::unique_ptr<T>(new typename std::remove_extent<T>::type[n]());
1360}
1361
1362/// This function isn't used and is only here to provide better compile errors.
1363template <class T, class... Args>
1364typename std::enable_if<std::extent<T>::value != 0>::type
1365make_unique(Args &&...) = delete;
1366
1367struct FreeDeleter {
1368 void operator()(void* v) {
1369 ::free(v);
1370 }
1371};
1372
1373template<typename First, typename Second>
1374struct pair_hash {
1375 size_t operator()(const std::pair<First, Second> &P) const {
1376 return std::hash<First>()(P.first) * 31 + std::hash<Second>()(P.second);
1377 }
1378};
1379
1380/// A functor like C++14's std::less<void> in its absence.
1381struct less {
1382 template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1383 return std::forward<A>(a) < std::forward<B>(b);
1384 }
1385};
1386
1387/// A functor like C++14's std::equal<void> in its absence.
1388struct equal {
1389 template <typename A, typename B> bool operator()(A &&a, B &&b) const {
1390 return std::forward<A>(a) == std::forward<B>(b);
1391 }
1392};
1393
1394/// Binary functor that adapts to any other binary functor after dereferencing
1395/// operands.
1396template <typename T> struct deref {
1397 T func;
1398
1399 // Could be further improved to cope with non-derivable functors and
1400 // non-binary functors (should be a variadic template member function
1401 // operator()).
1402 template <typename A, typename B>
1403 auto operator()(A &lhs, B &rhs) const -> decltype(func(*lhs, *rhs)) {
1404 assert(lhs)((lhs) ? static_cast<void> (0) : __assert_fail ("lhs", "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 1404, __PRETTY_FUNCTION__))
;
1405 assert(rhs)((rhs) ? static_cast<void> (0) : __assert_fail ("rhs", "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 1405, __PRETTY_FUNCTION__))
;
1406 return func(*lhs, *rhs);
1407 }
1408};
1409
1410namespace detail {
1411
1412template <typename R> class enumerator_iter;
1413
1414template <typename R> struct result_pair {
1415 friend class enumerator_iter<R>;
1416
1417 result_pair() = default;
1418 result_pair(std::size_t Index, IterOfRange<R> Iter)
1419 : Index(Index), Iter(Iter) {}
1420
1421 result_pair<R> &operator=(const result_pair<R> &Other) {
1422 Index = Other.Index;
1423 Iter = Other.Iter;
1424 return *this;
1425 }
1426
1427 std::size_t index() const { return Index; }
1428 const ValueOfRange<R> &value() const { return *Iter; }
1429 ValueOfRange<R> &value() { return *Iter; }
1430
1431private:
1432 std::size_t Index = std::numeric_limits<std::size_t>::max();
1433 IterOfRange<R> Iter;
1434};
1435
1436template <typename R>
1437class enumerator_iter
1438 : public iterator_facade_base<
1439 enumerator_iter<R>, std::forward_iterator_tag, result_pair<R>,
1440 typename std::iterator_traits<IterOfRange<R>>::difference_type,
1441 typename std::iterator_traits<IterOfRange<R>>::pointer,
1442 typename std::iterator_traits<IterOfRange<R>>::reference> {
1443 using result_type = result_pair<R>;
1444
1445public:
1446 explicit enumerator_iter(IterOfRange<R> EndIter)
1447 : Result(std::numeric_limits<size_t>::max(), EndIter) {}
1448
1449 enumerator_iter(std::size_t Index, IterOfRange<R> Iter)
1450 : Result(Index, Iter) {}
1451
1452 result_type &operator*() { return Result; }
1453 const result_type &operator*() const { return Result; }
1454
1455 enumerator_iter<R> &operator++() {
1456 assert(Result.Index != std::numeric_limits<size_t>::max())((Result.Index != std::numeric_limits<size_t>::max()) ?
static_cast<void> (0) : __assert_fail ("Result.Index != std::numeric_limits<size_t>::max()"
, "/build/llvm-toolchain-snapshot-8~svn350071/include/llvm/ADT/STLExtras.h"
, 1456, __PRETTY_FUNCTION__))
;
1457 ++Result.Iter;
1458 ++Result.Index;
1459 return *this;
1460 }
1461
1462 bool operator==(const enumerator_iter<R> &RHS) const {
1463 // Don't compare indices here, only iterators. It's possible for an end
1464 // iterator to have different indices depending on whether it was created
1465 // by calling std::end() versus incrementing a valid iterator.
1466 return Result.Iter == RHS.Result.Iter;
1467 }
1468
1469 enumerator_iter<R> &operator=(const enumerator_iter<R> &Other) {
1470 Result = Other.Result;
1471 return *this;
1472 }
1473
1474private:
1475 result_type Result;
1476};
1477
1478template <typename R> class enumerator {
1479public:
1480 explicit enumerator(R &&Range) : TheRange(std::forward<R>(Range)) {}
1481
1482 enumerator_iter<R> begin() {
1483 return enumerator_iter<R>(0, std::begin(TheRange));
1484 }
1485
1486 enumerator_iter<R> end() {
1487 return enumerator_iter<R>(std::end(TheRange));
1488 }
1489
1490private:
1491 R TheRange;
1492};
1493
1494} // end namespace detail
1495
1496/// Given an input range, returns a new range whose values are are pair (A,B)
1497/// such that A is the 0-based index of the item in the sequence, and B is
1498/// the value from the original sequence. Example:
1499///
1500/// std::vector<char> Items = {'A', 'B', 'C', 'D'};
1501/// for (auto X : enumerate(Items)) {
1502/// printf("Item %d - %c\n", X.index(), X.value());
1503/// }
1504///
1505/// Output:
1506/// Item 0 - A
1507/// Item 1 - B
1508/// Item 2 - C
1509/// Item 3 - D
1510///
1511template <typename R> detail::enumerator<R> enumerate(R &&TheRange) {
1512 return detail::enumerator<R>(std::forward<R>(TheRange));
1513}
1514
1515namespace detail {
1516
1517template <typename F, typename Tuple, std::size_t... I>
1518auto apply_tuple_impl(F &&f, Tuple &&t, index_sequence<I...>)
1519 -> decltype(std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...)) {
1520 return std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...);
1521}
1522
1523} // end namespace detail
1524
1525/// Given an input tuple (a1, a2, ..., an), pass the arguments of the
1526/// tuple variadically to f as if by calling f(a1, a2, ..., an) and
1527/// return the result.
1528template <typename F, typename Tuple>
1529auto apply_tuple(F &&f, Tuple &&t) -> decltype(detail::apply_tuple_impl(
1530 std::forward<F>(f), std::forward<Tuple>(t),
1531 build_index_impl<
1532 std::tuple_size<typename std::decay<Tuple>::type>::value>{})) {
1533 using Indices = build_index_impl<
1534 std::tuple_size<typename std::decay<Tuple>::type>::value>;
1535
1536 return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t),
1537 Indices{});
1538}
1539
1540/// Return true if the sequence [Begin, End) has exactly N items. Runs in O(N)
1541/// time. Not meant for use with random-access iterators.
1542template <typename IterTy>
1543bool hasNItems(
1544 IterTy &&Begin, IterTy &&End, unsigned N,
1545 typename std::enable_if<
1546 !std::is_same<
1547 typename std::iterator_traits<typename std::remove_reference<
1548 decltype(Begin)>::type>::iterator_category,
1549 std::random_access_iterator_tag>::value,
1550 void>::type * = nullptr) {
1551 for (; N; --N, ++Begin)
1552 if (Begin == End)
1553 return false; // Too few.
1554 return Begin == End;
1555}
1556
1557/// Return true if the sequence [Begin, End) has N or more items. Runs in O(N)
1558/// time. Not meant for use with random-access iterators.
1559template <typename IterTy>
1560bool hasNItemsOrMore(
1561 IterTy &&Begin, IterTy &&End, unsigned N,
1562 typename std::enable_if<
1563 !std::is_same<
1564 typename std::iterator_traits<typename std::remove_reference<
1565 decltype(Begin)>::type>::iterator_category,
1566 std::random_access_iterator_tag>::value,
1567 void>::type * = nullptr) {
1568 for (; N; --N, ++Begin)
1569 if (Begin == End)
1570 return false; // Too few.
1571 return true;
1572}
1573
1574} // end namespace llvm
1575
1576#endif // LLVM_ADT_STLEXTRAS_H