// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
+//
+// This file contains the declaration of the MCSymbol class.
+//
+//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCSYMBOL_H
#define LLVM_MC_MCSYMBOL_H
-#include <string>
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Compiler.h"
namespace llvm {
+ class MCExpr;
+ class MCSection;
+ class MCContext;
+ class raw_ostream;
+
+ /// MCSymbol - Instances of this class represent a symbol name in the MC file,
+ /// and MCSymbols are created and unique'd by the MCContext class. MCSymbols
+ /// should only be constructed with valid names for the object file.
+ ///
+ /// If the symbol is defined/emitted into the current translation unit, the
+ /// Section member is set to indicate what section it lives in. Otherwise, if
+ /// it is a reference to an external entity, it has a null section.
class MCSymbol {
- MCSection *Section;
- std::string Name;
+ // Special sentinal value for the absolute pseudo section.
+ //
+ // FIXME: Use a PointerInt wrapper for this?
+ static const MCSection *AbsolutePseudoSection;
+
+ /// Name - The name of the symbol. The referred-to string data is actually
+ /// held by the StringMap that lives in MCContext.
+ StringRef Name;
+
+ /// Section - The section the symbol is defined in. This is null for
+ /// undefined symbols, and the special AbsolutePseudoSection value for
+ /// absolute symbols.
+ const MCSection *Section;
+
+ /// Value - If non-null, the value for a variable symbol.
+ const MCExpr *Value;
+
+ /// IsTemporary - True if this is an assembler temporary label, which
+ /// typically does not survive in the .o file's symbol table. Usually
+ /// "Lfoo" or ".foo".
unsigned IsTemporary : 1;
- unsigned IsExternal : 1;
+ /// IsUsed - True if this symbol has been used.
+ mutable unsigned IsUsed : 1;
+
+ private: // MCContext creates and uniques these.
+ friend class MCExpr;
+ friend class MCContext;
+ MCSymbol(StringRef name, bool isTemporary)
+ : Name(name), Section(nullptr), Value(nullptr),
+ IsTemporary(isTemporary), IsUsed(false) {}
+
+ MCSymbol(const MCSymbol&) LLVM_DELETED_FUNCTION;
+ void operator=(const MCSymbol&) LLVM_DELETED_FUNCTION;
public:
- MCSymbol(const char *_Name, bool _IsTemporary)
- : Section(0), Name(_Name), IsTemporary(_IsTemporary), IsExternal(false) {}
+ /// getName - Get the symbol name.
+ StringRef getName() const { return Name; }
+
+ /// @name Accessors
+ /// @{
+
+ /// isTemporary - Check if this is an assembler temporary symbol.
+ bool isTemporary() const { return IsTemporary; }
+
+ /// isUsed - Check if this is used.
+ bool isUsed() const { return IsUsed; }
+ void setUsed(bool Value) const { IsUsed = Value; }
+
+ /// @}
+ /// @name Associated Sections
+ /// @{
+
+ /// isDefined - Check if this symbol is defined (i.e., it has an address).
+ ///
+ /// Defined symbols are either absolute or in some section.
+ bool isDefined() const {
+ return Section != nullptr;
+ }
+
+ /// isInSection - Check if this symbol is defined in some section (i.e., it
+ /// is defined but not absolute).
+ bool isInSection() const {
+ return isDefined() && !isAbsolute();
+ }
+
+ /// isUndefined - Check if this symbol undefined (i.e., implicitly defined).
+ bool isUndefined() const {
+ return !isDefined();
+ }
+
+ /// isAbsolute - Check if this is an absolute symbol.
+ bool isAbsolute() const {
+ return Section == AbsolutePseudoSection;
+ }
+
+ /// getSection - Get the section associated with a defined, non-absolute
+ /// symbol.
+ const MCSection &getSection() const {
+ assert(isInSection() && "Invalid accessor!");
+ return *Section;
+ }
+
+ /// setSection - Mark the symbol as defined in the section \p S.
+ void setSection(const MCSection &S) { Section = &S; }
+
+ /// setUndefined - Mark the symbol as undefined.
+ void setUndefined() {
+ Section = nullptr;
+ }
+
+ /// setAbsolute - Mark the symbol as absolute.
+ void setAbsolute() { Section = AbsolutePseudoSection; }
+
+ /// @}
+ /// @name Variable Symbols
+ /// @{
+
+ /// isVariable - Check if this is a variable symbol.
+ bool isVariable() const {
+ return Value != nullptr;
+ }
+
+ /// getVariableValue() - Get the value for variable symbols.
+ const MCExpr *getVariableValue() const {
+ assert(isVariable() && "Invalid accessor!");
+ IsUsed = true;
+ return Value;
+ }
+
+ // AliasedSymbol() - If this is an alias (a = b), return the symbol
+ // we ultimately point to. For a non-alias, this just returns the symbol
+ // itself.
+ const MCSymbol &AliasedSymbol() const;
+
+ void setVariableValue(const MCExpr *Value);
- MCSection *getSection() const { return Section; }
- void setSection(MCSection *Value) { Section = Value; }
+ /// @}
- bool isExternal() const { return IsExternal; }
- void setExternal(bool Value) { IsExternal = Value; }
+ /// print - Print the value to the stream \p OS.
+ void print(raw_ostream &OS) const;
- const std::string &getName() const { return Name; }
+ /// dump - Print the value to stderr.
+ void dump() const;
};
+ inline raw_ostream &operator<<(raw_ostream &OS, const MCSymbol &Sym) {
+ Sym.print(OS);
+ return OS;
+ }
} // end namespace llvm
#endif
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