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//===- SymbolTable.cpp ----------------------------------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "SymbolTable.h"
#include "Config.h"
#include "Memory.h"
#include "Strings.h"
#include "lld/Common/ErrorHandler.h"
#include <unordered_set>
#define DEBUG_TYPE "lld"
using namespace llvm;
using namespace lld;
using namespace lld::wasm;
SymbolTable *lld::wasm::Symtab;
void SymbolTable::addFile(InputFile *File) {
log("Processing: " + toString(File));
File->parse();
if (auto *F = dyn_cast<ObjFile>(File))
ObjectFiles.push_back(F);
}
void SymbolTable::reportRemainingUndefines() {
std::unordered_set<Symbol *> Undefs;
for (auto &I : SymMap) {
Symbol *Sym = I.second;
if (Sym->isUndefined() && !Sym->isWeak() &&
Config->AllowUndefinedSymbols.count(Sym->getName()) == 0) {
Undefs.insert(Sym);
}
}
if (Undefs.empty())
return;
for (ObjFile *File : ObjectFiles)
for (Symbol *Sym : File->getSymbols())
if (Undefs.count(Sym))
error(toString(File) + ": undefined symbol: " + toString(*Sym));
for (Symbol *Sym : Undefs)
if (!Sym->getFile())
error("undefined symbol: " + toString(*Sym));
}
Symbol *SymbolTable::find(StringRef Name) {
auto It = SymMap.find(CachedHashStringRef(Name));
if (It == SymMap.end())
return nullptr;
return It->second;
}
std::pair<Symbol *, bool> SymbolTable::insert(StringRef Name) {
Symbol *&Sym = SymMap[CachedHashStringRef(Name)];
if (Sym)
return {Sym, false};
Sym = make<Symbol>(Name, false);
return {Sym, true};
}
void SymbolTable::reportDuplicate(Symbol *Existing, InputFile *NewFile) {
error("duplicate symbol: " + toString(*Existing) + "\n>>> defined in " +
toString(Existing->getFile()) + "\n>>> defined in " +
toString(NewFile));
}
static void checkSymbolTypes(Symbol *Existing, InputFile *F,
const WasmSymbol *New) {
if (Existing->isLazy())
return;
bool NewIsFunction = New->Type == WasmSymbol::SymbolType::FUNCTION_EXPORT ||
New->Type == WasmSymbol::SymbolType::FUNCTION_IMPORT;
if (Existing->isFunction() == NewIsFunction)
return;
error("symbol type mismatch: " + New->Name + "\n>>> defined as " +
(Existing->isFunction() ? "Function" : "Global") + " in " +
toString(Existing->getFile()) + "\n>>> defined as " +
(NewIsFunction ? "Function" : "Global") + " in " + F->getName());
}
Symbol *SymbolTable::addDefinedGlobal(StringRef Name) {
DEBUG(dbgs() << "addDefinedGlobal: " << Name << "\n");
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name);
if (WasInserted)
S->update(Symbol::DefinedGlobalKind);
else if (!S->isGlobal())
error("symbol type mismatch: " + Name);
return S;
}
Symbol *SymbolTable::addDefined(InputFile *F, const WasmSymbol *Sym,
const InputSegment *Segment) {
DEBUG(dbgs() << "addDefined: " << Sym->Name << "\n");
Symbol *S;
bool WasInserted;
Symbol::Kind Kind = Symbol::DefinedFunctionKind;
if (Sym->Type == WasmSymbol::SymbolType::GLOBAL_EXPORT)
Kind = Symbol::DefinedGlobalKind;
std::tie(S, WasInserted) = insert(Sym->Name);
if (WasInserted) {
S->update(Kind, F, Sym, Segment);
} else if (!S->isDefined()) {
// The existing symbol table entry is undefined. The new symbol replaces
// it
DEBUG(dbgs() << "resolving existing undefined symbol: " << Sym->Name
<< "\n");
checkSymbolTypes(S, F, Sym);
S->update(Kind, F, Sym, Segment);
} else if (Sym->isWeak()) {
// the new symbol is weak we can ignore it
DEBUG(dbgs() << "existing symbol takes precensence\n");
} else if (S->isWeak()) {
// the new symbol is not weak and the existing symbol is, so we replace
// it
DEBUG(dbgs() << "replacing existing weak symbol\n");
S->update(Kind, F, Sym, Segment);
} else {
// niether symbol is week. They conflict.
reportDuplicate(S, F);
}
return S;
}
Symbol *SymbolTable::addUndefinedFunction(StringRef Name) {
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name);
if (WasInserted)
S->update(Symbol::UndefinedFunctionKind);
else if (!S->isFunction())
error("symbol type mismatch: " + Name);
return S;
}
Symbol *SymbolTable::addUndefined(InputFile *F, const WasmSymbol *Sym) {
DEBUG(dbgs() << "addUndefined: " << displayName(Sym->Name) << "\n");
Symbol *S;
bool WasInserted;
Symbol::Kind Kind = Symbol::UndefinedFunctionKind;
if (Sym->Type == WasmSymbol::SymbolType::GLOBAL_IMPORT)
Kind = Symbol::UndefinedGlobalKind;
std::tie(S, WasInserted) = insert(Sym->Name);
if (WasInserted) {
S->update(Kind, F, Sym);
} else if (S->isLazy()) {
DEBUG(dbgs() << "resolved by existing lazy\n");
auto *AF = cast<ArchiveFile>(S->getFile());
AF->addMember(&S->getArchiveSymbol());
} else if (S->isDefined()) {
DEBUG(dbgs() << "resolved by existing\n");
checkSymbolTypes(S, F, Sym);
}
return S;
}
void SymbolTable::addLazy(ArchiveFile *F, const Archive::Symbol *Sym) {
DEBUG(dbgs() << "addLazy: " << displayName(Sym->getName()) << "\n");
StringRef Name = Sym->getName();
Symbol *S;
bool WasInserted;
std::tie(S, WasInserted) = insert(Name);
if (WasInserted) {
S->update(Symbol::LazyKind, F);
S->setArchiveSymbol(*Sym);
} else if (S->isUndefined()) {
// There is an existing undefined symbol. The can load from the
// archive.
DEBUG(dbgs() << "replacing existing undefined\n");
F->addMember(Sym);
}
}
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