// 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/PointerIntPair.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/Support/Compiler.h"
namespace llvm {
- class MCAtom;
-
- class MCSymbol {
- MCAtom *Atom;
- std::string Name;
- unsigned IsTemporary : 1;
+class MCExpr;
+class MCSymbol;
+class MCFragment;
+class MCSection;
+class MCContext;
+class raw_ostream;
- public:
- MCSymbol(MCAtom *_Atom, const char *_Name, bool _IsTemporary)
- : Atom(_Atom), Name(_Name), IsTemporary(_IsTemporary) {}
+// TODO: Merge completely with MCSymbol.
+class MCSymbolData {
+ /// Fragment - The fragment this symbol's value is relative to, if any. Also
+ /// stores if this symbol is visible outside this translation unit (bit 0) or
+ /// if it is private extern (bit 1).
+ PointerIntPair<MCFragment *, 2> Fragment;
- MCAtom *getAtom() { return Atom; }
+ union {
+ /// Offset - The offset to apply to the fragment address to form this
+ /// symbol's value.
+ uint64_t Offset;
- const std::string &getName() { return Name; }
+ /// CommonSize - The size of the symbol, if it is 'common'.
+ uint64_t CommonSize;
};
+ /// SymbolSize - An expression describing how to calculate the size of
+ /// a symbol. If a symbol has no size this field will be NULL.
+ const MCExpr *SymbolSize = nullptr;
+
+ /// CommonAlign - The alignment of the symbol, if it is 'common', or -1.
+ //
+ // FIXME: Pack this in with other fields?
+ unsigned CommonAlign = -1U;
+
+ /// Flags - The Flags field is used by object file implementations to store
+ /// additional per symbol information which is not easily classified.
+ uint32_t Flags = 0;
+
+public:
+ MCSymbolData() { Offset = 0; }
+
+ MCFragment *getFragment() const { return Fragment.getPointer(); }
+ void setFragment(MCFragment *Value) { Fragment.setPointer(Value); }
+
+ uint64_t getOffset() const {
+ assert(!isCommon());
+ return Offset;
+ }
+ void setOffset(uint64_t Value) {
+ assert(!isCommon());
+ Offset = Value;
+ }
+
+ /// @}
+ /// \name Symbol Attributes
+ /// @{
+
+ bool isExternal() const { return Fragment.getInt() & 1; }
+ void setExternal(bool Value) {
+ Fragment.setInt((Fragment.getInt() & ~1) | unsigned(Value));
+ }
+
+ bool isPrivateExtern() const { return Fragment.getInt() & 2; }
+ void setPrivateExtern(bool Value) {
+ Fragment.setInt((Fragment.getInt() & ~2) | (unsigned(Value) << 1));
+ }
+
+ /// isCommon - Is this a 'common' symbol.
+ bool isCommon() const { return CommonAlign != -1U; }
+
+ /// setCommon - Mark this symbol as being 'common'.
+ ///
+ /// \param Size - The size of the symbol.
+ /// \param Align - The alignment of the symbol.
+ void setCommon(uint64_t Size, unsigned Align) {
+ assert(getOffset() == 0);
+ CommonSize = Size;
+ CommonAlign = Align;
+ }
+
+ /// getCommonSize - Return the size of a 'common' symbol.
+ uint64_t getCommonSize() const {
+ assert(isCommon() && "Not a 'common' symbol!");
+ return CommonSize;
+ }
+
+ void setSize(const MCExpr *SS) { SymbolSize = SS; }
+
+ const MCExpr *getSize() const { return SymbolSize; }
+
+ /// getCommonAlignment - Return the alignment of a 'common' symbol.
+ unsigned getCommonAlignment() const {
+ assert(isCommon() && "Not a 'common' symbol!");
+ return CommonAlign;
+ }
+
+ /// getFlags - Get the (implementation defined) symbol flags.
+ uint32_t getFlags() const { return Flags; }
+
+ /// setFlags - Set the (implementation defined) symbol flags.
+ void setFlags(uint32_t Value) { Flags = Value; }
+
+ /// modifyFlags - Modify the flags via a mask
+ void modifyFlags(uint32_t Value, uint32_t Mask) {
+ Flags = (Flags & ~Mask) | Value;
+ }
+
+ /// @}
+
+ void dump() const;
+};
+
+/// MCSymbol - Instances of this class represent a symbol name in the MC file,
+/// and MCSymbols are created and uniqued 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 {
+ // Special sentinal value for the absolute pseudo section.
+ //
+ // FIXME: Use a PointerInt wrapper for this?
+ static MCSection *AbsolutePseudoSection;
+
+ /// Name - The name of the symbol. The referred-to string data is actually
+ /// held by the StringMap that lives in MCContext.
+ const StringMapEntry<bool> *Name;
+
+ /// The section the symbol is defined in. This is null for undefined symbols,
+ /// and the special AbsolutePseudoSection value for absolute symbols. If this
+ /// is a variable symbol, this caches the variable value's section.
+ mutable 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;
+
+ /// \brief True if this symbol can be redefined.
+ unsigned IsRedefinable : 1;
+
+ /// IsUsed - True if this symbol has been used.
+ mutable unsigned IsUsed : 1;
+
+ mutable bool HasData : 1;
+
+ /// Index field, for use by the object file implementation.
+ mutable uint64_t Index : 60;
+
+ mutable MCSymbolData Data;
+
+private: // MCContext creates and uniques these.
+ friend class MCExpr;
+ friend class MCContext;
+ MCSymbol(const StringMapEntry<bool> *Name, bool isTemporary)
+ : Name(Name), Section(nullptr), Value(nullptr), IsTemporary(isTemporary),
+ IsRedefinable(false), IsUsed(false), HasData(false), Index(0) {}
+
+ MCSymbol(const MCSymbol &) = delete;
+ void operator=(const MCSymbol &) = delete;
+ MCSection *getSectionPtr() const {
+ if (Section || !Value)
+ return Section;
+ return Section = Value->FindAssociatedSection();
+ }
+
+public:
+ /// getName - Get the symbol name.
+ StringRef getName() const { return Name ? Name->first() : ""; }
+
+ bool hasData() const { return HasData; }
+
+ /// Get associated symbol data.
+ MCSymbolData &getData() const {
+ assert(HasData && "Missing symbol data!");
+ return Data;
+ }
+
+ /// Initialize symbol data.
+ ///
+ /// Nothing really to do here, but this is enables an assertion that \a
+ /// MCAssembler::getOrCreateSymbolData() has actually been called before
+ /// anyone calls \a getData().
+ void initializeData() const { HasData = true; }
+
+ /// \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; }
+
+ /// \brief Check if this symbol is redefinable.
+ bool isRedefinable() const { return IsRedefinable; }
+ /// \brief Mark this symbol as redefinable.
+ void setRedefinable(bool Value) { IsRedefinable = Value; }
+ /// \brief Prepare this symbol to be redefined.
+ void redefineIfPossible() {
+ if (IsRedefinable) {
+ Value = nullptr;
+ Section = nullptr;
+ IsRedefinable = false;
+ }
+ }
+
+ /// @}
+ /// \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 getSectionPtr() != 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 getSectionPtr() == AbsolutePseudoSection; }
+
+ /// Get the section associated with a defined, non-absolute symbol.
+ MCSection &getSection() const {
+ assert(isInSection() && "Invalid accessor!");
+ return *getSectionPtr();
+ }
+
+ /// Mark the symbol as defined in the section \p S.
+ void setSection(MCSection &S) {
+ assert(!isVariable() && "Cannot set section of variable");
+ Section = &S;
+ }
+
+ /// setUndefined - Mark the symbol as undefined.
+ void setUndefined() { Section = nullptr; }
+
+ /// @}
+ /// \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;
+ }
+
+ void setVariableValue(const MCExpr *Value);
+
+ /// @}
+
+ /// Get the (implementation defined) index.
+ uint64_t getIndex() const {
+ assert(HasData && "Uninitialized symbol data");
+ return Index;
+ }
+
+ /// Set the (implementation defined) index.
+ void setIndex(uint64_t Value) const {
+ assert(HasData && "Uninitialized symbol data");
+ assert(!(Value >> 60) && "Not enough bits for value");
+ Index = Value;
+ }
+
+ /// print - Print the value to the stream \p OS.
+ void print(raw_ostream &OS) const;
+
+ /// 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