/// "Lfoo" or ".foo".
unsigned IsTemporary : 1;
+ /// IsUsedInExpr - True if this symbol has been used in an expression and
+ /// cannot be redefined.
+ unsigned IsUsedInExpr : 1;
+
private: // MCContext creates and uniques these.
friend class MCContext;
MCSymbol(StringRef name, bool isTemporary)
- : Name(name), Section(0), Value(0), IsTemporary(isTemporary) {}
+ : Name(name), Section(0), Value(0),
+ IsTemporary(isTemporary), IsUsedInExpr(false) {}
MCSymbol(const MCSymbol&); // DO NOT IMPLEMENT
void operator=(const MCSymbol&); // DO NOT IMPLEMENT
/// getName - Get the symbol name.
StringRef getName() const { return Name; }
- /// @name Symbol Type
+ /// @name Accessors
/// @{
/// isTemporary - Check if this is an assembler temporary symbol.
- bool isTemporary() const {
- return IsTemporary;
- }
+ bool isTemporary() const { return IsTemporary; }
+
+ /// isUsedInExpr - Check if this is an assembler temporary symbol.
+ bool isUsedInExpr() const { return IsUsedInExpr; }
+ void setUsedInExpr(bool Value) { IsUsedInExpr = Value; }
/// @}
/// @name Associated Sections
std::pair<StringRef, StringRef> Split = getTok().getIdentifier().split('@');
MCSymbol *Sym = CreateSymbol(Split.first);
+ // Mark the symbol as used in an expression.
+ Sym->setUsedInExpr(true);
+
// Lookup the symbol variant if used.
MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
if (Split.first.size() != getTok().getIdentifier().size())
//
// FIXME: Diagnostics. Note the location of the definition as a label.
// FIXME: Diagnose assignment to protected identifier (e.g., register name).
- if (!Sym->isUndefined() && !Sym->isAbsolute())
+ if (Sym->isUndefined() && !Sym->isUsedInExpr())
+ ; // Allow redefinitions of undefined symbols only used in directives.
+ else if (!Sym->isUndefined() && !Sym->isAbsolute())
return Error(EqualLoc, "redefinition of '" + Name + "'");
else if (!Sym->isVariable())
return Error(EqualLoc, "invalid assignment to '" + Name + "'");
// FIXME: Handle '.'.
+ Sym->setUsedInExpr(true);
+
// Do the assignment.
Out.EmitAssignment(Sym, Value);