bool ELFObjectWriter::isInSymtab(const MCAsmLayout &Layout,
const MCSymbolELF &Symbol, bool Used,
bool Renamed) {
if (Symbol.isVariable()) {
const MCExpr *Expr = Symbol.getVariableValue();
if (const MCSymbolRefExpr *Ref = dyn_cast<MCSymbolRefExpr>(Expr)) {
if (Ref->getKind() == MCSymbolRefExpr::VK_WEAKREF)
return false;
}
}
if (Used)
return true;
if (Renamed)
return false;
if (Symbol.isVariable() && Symbol.isUndefined()) {
// FIXME: this is here just to diagnose the case of a var = commmon_sym.
Layout.getBaseSymbol(Symbol);
return false;
}
if (Symbol.isUndefined() && !Symbol.isBindingSet())
return false;
if (Symbol.isTemporary())
return false;
if (Symbol.getType() == ELF::STT_SECTION)
return false;
return true;
}
// True if the assembler knows nothing about the final value of the symbol.
// This doesn't cover the comdat issues, since in those cases the assembler
// can at least know that all symbols in the section will move together.
static bool isWeak(const MCSymbolELF &Sym) {
if (Sym.getType() == ELF::STT_GNU_IFUNC)
return true;
switch (Sym.getBinding()) {
default:
llvm_unreachable("Unknown binding");
case ELF::STB_LOCAL:
return false;
case ELF::STB_GLOBAL:
return false;
case ELF::STB_WEAK:
case ELF::STB_GNU_UNIQUE:
return true;
}
}