1 //===- SymbolTable.h --------------------------------------------*- C++ -*-===//
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
7 //===----------------------------------------------------------------------===//
9 #ifndef LLD_ELF_SYMBOL_TABLE_H
10 #define LLD_ELF_SYMBOL_TABLE_H
13 #include "llvm/ADT/CachedHashString.h"
14 #include "llvm/ADT/DenseMap.h"
15 #include "llvm/Support/Compiler.h"
22 struct ArmCmseEntryFunction
{
27 // SymbolTable is a bucket of all known symbols, including defined,
28 // undefined, or lazy symbols (the last one is symbols in archive
29 // files whose archive members are not yet loaded).
31 // We put all symbols of all files to a SymbolTable, and the
32 // SymbolTable selects the "best" symbols if there are name
33 // conflicts. For example, obviously, a defined symbol is better than
34 // an undefined symbol. Or, if there's a conflict between a lazy and a
35 // undefined, it'll read an archive member to read a real definition
36 // to replace the lazy symbol. The logic is implemented in the
37 // add*() functions, which are called by input files as they are parsed. There
38 // is one add* function per symbol type.
41 SymbolTable(Ctx
&ctx
) : ctx(ctx
) {}
42 ArrayRef
<Symbol
*> getSymbols() const { return symVector
; }
44 void wrap(Symbol
*sym
, Symbol
*real
, Symbol
*wrap
);
46 Symbol
*insert(StringRef name
);
48 template <typename T
> Symbol
*addSymbol(const T
&newSym
) {
49 Symbol
*sym
= insert(newSym
.getName());
50 sym
->resolve(ctx
, newSym
);
53 Symbol
*addAndCheckDuplicate(Ctx
&, const Defined
&newSym
);
55 void scanVersionScript();
57 Symbol
*find(StringRef name
);
59 void handleDynamicList();
61 Symbol
*addUnusedUndefined(StringRef name
,
62 uint8_t binding
= llvm::ELF::STB_GLOBAL
);
64 // Set of .so files to not link the same shared object file more than once.
65 llvm::DenseMap
<llvm::CachedHashStringRef
, SharedFile
*> soNames
;
67 // Comdat groups define "link once" sections. If two comdat groups have the
68 // same name, only one of them is linked, and the other is ignored. This map
69 // is used to uniquify them.
70 llvm::DenseMap
<llvm::CachedHashStringRef
, const InputFile
*> comdatGroups
;
72 // The Map of __acle_se_<sym>, <sym> pairs found in the input objects.
73 // Key is the <sym> name.
74 llvm::SmallMapVector
<StringRef
, ArmCmseEntryFunction
, 1> cmseSymMap
;
76 // Map of symbols defined in the Arm CMSE import library. The linker must
77 // preserve the addresses in the output objects.
78 llvm::StringMap
<Defined
*> cmseImportLib
;
80 // True if <sym> from the input Arm CMSE import library is written to the
81 // output Arm CMSE import library.
82 llvm::StringMap
<bool> inCMSEOutImpLib
;
85 SmallVector
<Symbol
*, 0> findByVersion(SymbolVersion ver
);
86 SmallVector
<Symbol
*, 0> findAllByVersion(SymbolVersion ver
,
87 bool includeNonDefault
);
89 llvm::StringMap
<SmallVector
<Symbol
*, 0>> &getDemangledSyms();
90 bool assignExactVersion(SymbolVersion ver
, uint16_t versionId
,
91 StringRef versionName
, bool includeNonDefault
);
92 void assignWildcardVersion(SymbolVersion ver
, uint16_t versionId
,
93 bool includeNonDefault
);
97 // Global symbols and a map from symbol name to the index. The order is not
98 // defined. We can use an arbitrary order, but it has to be deterministic even
99 // when cross linking.
100 llvm::DenseMap
<llvm::CachedHashStringRef
, int> symMap
;
101 SmallVector
<Symbol
*, 0> symVector
;
103 // A map from demangled symbol names to their symbol objects.
104 // This mapping is 1:N because two symbols with different versions
105 // can have the same name. We use this map to handle "extern C++ {}"
106 // directive in version scripts.
107 std::optional
<llvm::StringMap
<SmallVector
<Symbol
*, 0>>> demangledSyms
;
110 } // namespace lld::elf