1//===- Config.h -------------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLD_WASM_CONFIG_H
10#define LLD_WASM_CONFIG_H
11
12#include "llvm/ADT/SmallVector.h"
13#include "llvm/ADT/StringRef.h"
14#include "llvm/ADT/StringSet.h"
15#include "llvm/ADT/Twine.h"
16#include "llvm/BinaryFormat/Wasm.h"
17#include "llvm/Support/CachePruning.h"
18#include <optional>
19
20namespace llvm {
21enum class CodeGenOptLevel;
22} // namespace llvm
23
24namespace lld::wasm {
25
26class InputFile;
27class StubFile;
28class ObjFile;
29class SharedFile;
30class BitcodeFile;
31class InputTable;
32class InputGlobal;
33class InputFunction;
34class Symbol;
35class DefinedData;
36class GlobalSymbol;
37class DefinedFunction;
38class UndefinedGlobal;
39class TableSymbol;
40
41// For --unresolved-symbols.
42enum class UnresolvedPolicy { ReportError, Warn, Ignore, ImportDynamic };
43
44// For --build-id.
45enum class BuildIdKind { None, Fast, Sha1, Hexstring, Uuid };
46
47// This struct contains the global configuration for the linker.
48// Most fields are direct mapping from the command line options
49// and such fields have the same name as the corresponding options.
50// Most fields are initialized by the driver.
51struct Config {
52 bool allowMultipleDefinition;
53 bool bsymbolic;
54 bool checkFeatures;
55 bool compressRelocations;
56 bool demangle;
57 bool disableVerify;
58 bool experimentalPic;
59 bool emitRelocs;
60 bool exportAll;
61 bool exportDynamic;
62 bool exportTable;
63 bool extendedConst;
64 bool growableTable;
65 bool gcSections;
66 llvm::StringSet<> keepSections;
67 std::optional<std::pair<llvm::StringRef, llvm::StringRef>> memoryImport;
68 std::optional<llvm::StringRef> memoryExport;
69 bool sharedMemory;
70 bool importTable;
71 bool importUndefined;
72 std::optional<bool> is64;
73 bool mergeDataSegments;
74 bool noinhibitExec;
75 bool pie;
76 bool printGcSections;
77 bool relocatable;
78 bool saveTemps;
79 bool shared;
80 bool shlibSigCheck;
81 bool stripAll;
82 bool stripDebug;
83 bool stackFirst;
84 // Because dyamanic linking under Wasm is still experimental we default to
85 // static linking
86 bool isStatic = true;
87 bool thinLTOEmitImportsFiles;
88 bool thinLTOEmitIndexFiles;
89 bool thinLTOIndexOnly;
90 bool trace;
91 uint64_t globalBase;
92 uint64_t initialHeap;
93 uint64_t initialMemory;
94 uint64_t maxMemory;
95 bool noGrowableMemory;
96 // The table offset at which to place function addresses. We reserve zero
97 // for the null function pointer. This gets set to 1 for executables and 0
98 // for shared libraries (since they always added to a dynamic offset at
99 // runtime).
100 uint64_t tableBase;
101 uint64_t zStackSize;
102 uint64_t pageSize;
103 unsigned ltoPartitions;
104 unsigned ltoo;
105 llvm::CodeGenOptLevel ltoCgo;
106 unsigned optimize;
107 bool ltoDebugPassManager;
108 UnresolvedPolicy unresolvedSymbols;
109 BuildIdKind buildId = BuildIdKind::None;
110
111 llvm::StringRef entry;
112 llvm::StringRef ltoObjPath;
113 llvm::StringRef mapFile;
114 llvm::StringRef outputFile;
115 llvm::StringRef soName;
116 llvm::StringRef thinLTOCacheDir;
117 llvm::StringRef thinLTOJobs;
118 llvm::StringRef thinLTOIndexOnlyArg;
119 std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace;
120 llvm::StringRef thinLTOPrefixReplaceOld;
121 llvm::StringRef thinLTOPrefixReplaceNew;
122 llvm::StringRef thinLTOPrefixReplaceNativeObject;
123 llvm::StringRef whyExtract;
124
125 llvm::StringSet<> allowUndefinedSymbols;
126 llvm::StringSet<> exportedSymbols;
127 std::vector<llvm::StringRef> requiredExports;
128 llvm::SmallVector<llvm::StringRef, 0> searchPaths;
129 llvm::SmallVector<llvm::StringRef, 0> rpath;
130 llvm::CachePruningPolicy thinLTOCachePolicy;
131 std::optional<std::vector<std::string>> features;
132 std::optional<std::vector<std::string>> extraFeatures;
133 llvm::SmallVector<uint8_t, 0> buildIdVector;
134};
135
136// The Ctx object hold all other (non-configuration) global state.
137struct Ctx {
138 Config arg;
139
140 llvm::SmallVector<ObjFile *, 0> objectFiles;
141 llvm::SmallVector<StubFile *, 0> stubFiles;
142 llvm::SmallVector<SharedFile *, 0> sharedFiles;
143 llvm::SmallVector<BitcodeFile *, 0> bitcodeFiles;
144 llvm::SmallVector<BitcodeFile *, 0> lazyBitcodeFiles;
145 llvm::SmallVector<InputFunction *, 0> syntheticFunctions;
146 llvm::SmallVector<InputGlobal *, 0> syntheticGlobals;
147 llvm::SmallVector<InputTable *, 0> syntheticTables;
148
149 // linker-generated symbols
150 struct WasmSym {
151 // __global_base
152 // Symbol marking the start of the global section.
153 DefinedData *globalBase;
154
155 // __stack_pointer/__stack_low/__stack_high
156 // Global that holds current value of stack pointer and data symbols marking
157 // the start and end of the stack region. stackPointer is initialized to
158 // stackHigh and grows downwards towards stackLow
159 GlobalSymbol *stackPointer;
160 DefinedData *stackLow;
161 DefinedData *stackHigh;
162
163 // __tls_base
164 // Global that holds the address of the base of the current thread's
165 // TLS block.
166 GlobalSymbol *tlsBase;
167
168 // __tls_size
169 // Symbol whose value is the size of the TLS block.
170 GlobalSymbol *tlsSize;
171
172 // __tls_size
173 // Symbol whose value is the alignment of the TLS block.
174 GlobalSymbol *tlsAlign;
175
176 // __data_end
177 // Symbol marking the end of the data and bss.
178 DefinedData *dataEnd;
179
180 // __heap_base/__heap_end
181 // Symbols marking the beginning and end of the "heap". It starts at the end
182 // of the data, bss and explicit stack, and extends to the end of the linear
183 // memory allocated by wasm-ld. This region of memory is not used by the
184 // linked code, so it may be used as a backing store for `sbrk` or `malloc`
185 // implementations.
186 DefinedData *heapBase;
187 DefinedData *heapEnd;
188
189 // __wasm_first_page_end
190 // A symbol whose address is the end of the first page in memory (if any).
191 DefinedData *firstPageEnd;
192
193 // __wasm_init_memory_flag
194 // Symbol whose contents are nonzero iff memory has already been
195 // initialized.
196 DefinedData *initMemoryFlag;
197
198 // __wasm_init_memory
199 // Function that initializes passive data segments during instantiation.
200 DefinedFunction *initMemory;
201
202 // __wasm_call_ctors
203 // Function that directly calls all ctors in priority order.
204 DefinedFunction *callCtors;
205
206 // __wasm_call_dtors
207 // Function that calls the libc/etc. cleanup function.
208 DefinedFunction *callDtors;
209
210 // __wasm_apply_global_relocs
211 // Function that applies relocations to wasm globals post-instantiation.
212 // Unlike __wasm_apply_data_relocs this needs to run on every thread.
213 DefinedFunction *applyGlobalRelocs;
214
215 // __wasm_apply_tls_relocs
216 // Like __wasm_apply_data_relocs but for TLS section. These must be
217 // delayed until __wasm_init_tls.
218 DefinedFunction *applyTLSRelocs;
219
220 // __wasm_apply_global_tls_relocs
221 // Like applyGlobalRelocs but for globals that hold TLS addresses. These
222 // must be delayed until __wasm_init_tls.
223 DefinedFunction *applyGlobalTLSRelocs;
224
225 // __wasm_init_tls
226 // Function that allocates thread-local storage and initializes it.
227 DefinedFunction *initTLS;
228
229 // Pointer to the function that is to be used in the start section.
230 // (normally an alias of initMemory, or applyGlobalRelocs).
231 DefinedFunction *startFunction;
232
233 // __dso_handle
234 // Symbol used in calls to __cxa_atexit to determine current DLL
235 DefinedData *dsoHandle;
236
237 // __table_base
238 // Used in PIC code for offset of indirect function table
239 UndefinedGlobal *tableBase;
240 DefinedData *definedTableBase;
241
242 // __memory_base
243 // Used in PIC code for offset of global data
244 UndefinedGlobal *memoryBase;
245 DefinedData *definedMemoryBase;
246
247 // __indirect_function_table
248 // Used as an address space for function pointers, with each function that
249 // is used as a function pointer being allocated a slot.
250 TableSymbol *indirectFunctionTable;
251 };
252 WasmSym sym;
253
254 // True if we are creating position-independent code.
255 bool isPic = false;
256
257 // True if we have an MVP input that uses __indirect_function_table and which
258 // requires it to be allocated to table number 0.
259 bool legacyFunctionTable = false;
260
261 // Will be set to true if bss data segments should be emitted. In most cases
262 // this is not necessary.
263 bool emitBssSegments = false;
264
265 // A tuple of (reference, extractedFile, sym). Used by --why-extract=.
266 llvm::SmallVector<std::tuple<std::string, const InputFile *, const Symbol &>,
267 0>
268 whyExtractRecords;
269
270 Ctx();
271 void reset();
272};
273
274extern Ctx ctx;
275
276void errorOrWarn(const llvm::Twine &msg);
277
278} // namespace lld::wasm
279
280#endif
281