X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FMC%2FMCSymbol.h;h=b2910dfccd637abc15622fa3d736f5a252360100;hb=d2e1e42c1a10d05067832eae990ddc1fa55c9c34;hp=26b416e47bc0d26454cb0c0b4702eb0177423046;hpb=4652459f64ed33e0bc21e9044b0a351c39c067c7;p=oota-llvm.git diff --git a/include/llvm/MC/MCSymbol.h b/include/llvm/MC/MCSymbol.h index 26b416e47bc..b2910dfccd6 100644 --- a/include/llvm/MC/MCSymbol.h +++ b/include/llvm/MC/MCSymbol.h @@ -15,11 +15,13 @@ #define LLVM_MC_MCSYMBOL_H #include "llvm/ADT/PointerIntPair.h" -#include "llvm/ADT/StringRef.h" -#include "llvm/MC/MCExpr.h" +#include "llvm/ADT/PointerUnion.h" +#include "llvm/ADT/StringMap.h" +#include "llvm/MC/MCAssembler.h" #include "llvm/Support/Compiler.h" namespace llvm { +class MCAsmInfo; class MCExpr; class MCSymbol; class MCFragment; @@ -27,116 +29,6 @@ class MCSection; class MCContext; class raw_ostream; -// 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 Fragment; - - union { - /// Offset - The offset to apply to the fragment address to form this - /// symbol's value. - uint64_t Offset = 0; - - /// 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; - - /// Index - Index field, for use by the object file implementation. - uint64_t Index = 0; - -public: - 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; - } - - /// getIndex - Get the (implementation defined) index. - uint64_t getIndex() const { return Index; } - - /// setIndex - Set the (implementation defined) index. - void setIndex(uint64_t Value) { Index = 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. @@ -145,23 +37,47 @@ public: /// 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 { +protected: + /// The kind of the symbol. If it is any value other than unset then this + /// class is actually one of the appropriate subclasses of MCSymbol. + enum SymbolKind { + SymbolKindUnset, + SymbolKindCOFF, + SymbolKindELF, + SymbolKindMachO, + }; + + /// A symbol can contain an Offset, or Value, or be Common, but never more + /// than one of these. + enum Contents : uint8_t { + SymContentsUnset, + SymContentsOffset, + SymContentsVariable, + SymContentsCommon, + }; + // 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. If this is a variable symbol, this caches the - /// variable value's section. - mutable const MCSection *Section; - - /// Value - If non-null, the value for a variable symbol. - const MCExpr *Value; + static MCSection *AbsolutePseudoSection; + + /// If a symbol has a Fragment, the section is implied, so we only need + /// one pointer. + /// FIXME: We might be able to simplify this by having the asm streamer create + /// dummy fragments. + /// If this is a section, then it gives 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. + /// + /// If this is a fragment, then it gives the fragment this symbol's value is + /// relative to, if any. + /// + /// For the 'HasName' integer, this is true if this symbol is named. + /// A named symbol will have a pointer to the name allocated in the bytes + /// immediately prior to the MCSymbol. + mutable PointerIntPair, 1> + SectionOrFragmentAndHasName; /// IsTemporary - True if this is an assembler temporary label, which /// typically does not survive in the .o file's symbol table. Usually @@ -174,42 +90,130 @@ class MCSymbol { /// IsUsed - True if this symbol has been used. mutable unsigned IsUsed : 1; - mutable bool HasData : 1; - mutable MCSymbolData Data; + mutable bool IsRegistered : 1; + + /// This symbol is visible outside this translation unit. + mutable unsigned IsExternal : 1; + + /// This symbol is private extern. + mutable unsigned IsPrivateExtern : 1; -private: // MCContext creates and uniques these. + /// LLVM RTTI discriminator. This is actually a SymbolKind enumerator, but is + /// unsigned to avoid sign extension and achieve better bitpacking with MSVC. + unsigned Kind : 2; + + /// True if we have created a relocation that uses this symbol. + mutable unsigned IsUsedInReloc : 1; + + /// This is actually a Contents enumerator, but is unsigned to avoid sign + /// extension and achieve better bitpacking with MSVC. + unsigned SymbolContents : 2; + + /// The alignment of the symbol, if it is 'common', or -1. + /// + /// The alignment is stored as log2(align) + 1. This allows all values from + /// 0 to 2^31 to be stored which is every power of 2 representable by an + /// unsigned. + enum : unsigned { NumCommonAlignmentBits = 5 }; + unsigned CommonAlignLog2 : NumCommonAlignmentBits; + + /// The Flags field is used by object file implementations to store + /// additional per symbol information which is not easily classified. + enum : unsigned { NumFlagsBits = 16 }; + mutable uint32_t Flags : NumFlagsBits; + + /// Index field, for use by the object file implementation. + mutable uint32_t Index = 0; + + union { + /// The offset to apply to the fragment address to form this symbol's value. + uint64_t Offset; + + /// The size of the symbol, if it is 'common'. + uint64_t CommonSize; + + /// If non-null, the value for a variable symbol. + const MCExpr *Value; + }; + +protected: // MCContext creates and uniques these. friend class MCExpr; friend class MCContext; - MCSymbol(StringRef name, bool isTemporary) - : Name(name), Section(nullptr), Value(nullptr), IsTemporary(isTemporary), - IsRedefinable(false), IsUsed(false), HasData(false) {} + + /// \brief The name for a symbol. + /// MCSymbol contains a uint64_t so is probably aligned to 8. On a 32-bit + /// system, the name is a pointer so isn't going to satisfy the 8 byte + /// alignment of uint64_t. Account for that here. + typedef union { + const StringMapEntry *NameEntry; + uint64_t AlignmentPadding; + } NameEntryStorageTy; + + MCSymbol(SymbolKind Kind, const StringMapEntry *Name, bool isTemporary) + : IsTemporary(isTemporary), IsRedefinable(false), IsUsed(false), + IsRegistered(false), IsExternal(false), IsPrivateExtern(false), + Kind(Kind), IsUsedInReloc(false), SymbolContents(SymContentsUnset), + CommonAlignLog2(0), Flags(0) { + Offset = 0; + SectionOrFragmentAndHasName.setInt(!!Name); + if (Name) + getNameEntryPtr() = Name; + } + + // Provide custom new/delete as we will only allocate space for a name + // if we need one. + void *operator new(size_t s, const StringMapEntry *Name, + MCContext &Ctx); + +private: + + void operator delete(void *); + /// \brief Placement delete - required by std, but never called. + void operator delete(void*, unsigned) { + llvm_unreachable("Constructor throws?"); + } + /// \brief Placement delete - required by std, but never called. + void operator delete(void*, unsigned, bool) { + llvm_unreachable("Constructor throws?"); + } MCSymbol(const MCSymbol &) = delete; void operator=(const MCSymbol &) = delete; - const MCSection *getSectionPtr() const { - if (Section || !Value) + MCSection *getSectionPtr() const { + if (MCFragment *F = getFragment()) + return F->getParent(); + const auto &SectionOrFragment = SectionOrFragmentAndHasName.getPointer(); + assert(!SectionOrFragment.is() && "Section or null expected"); + MCSection *Section = SectionOrFragment.dyn_cast(); + if (Section || !isVariable()) return Section; - return Section = Value->FindAssociatedSection(); + return Section = getVariableValue()->findAssociatedSection(); + } + + /// \brief Get a reference to the name field. Requires that we have a name + const StringMapEntry *&getNameEntryPtr() { + assert(SectionOrFragmentAndHasName.getInt() && "Name is required"); + NameEntryStorageTy *Name = reinterpret_cast(this); + return (*(Name - 1)).NameEntry; + } + const StringMapEntry *&getNameEntryPtr() const { + return const_cast(this)->getNameEntryPtr(); } public: /// getName - Get the symbol name. - StringRef getName() const { return Name; } - - bool hasData() const { return HasData; } + StringRef getName() const { + if (!SectionOrFragmentAndHasName.getInt()) + return StringRef(); - /// Get associated symbol data. - MCSymbolData &getData() const { - assert(HasData && "Missing symbol data!"); - return Data; + return getNameEntryPtr()->first(); } - /// 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; } + bool isRegistered() const { return IsRegistered; } + void setIsRegistered(bool Value) const { IsRegistered = Value; } + + void setUsedInReloc() const { IsUsedInReloc = true; } + bool isUsedInReloc() const { return IsUsedInReloc; } /// \name Accessors /// @{ @@ -228,8 +232,11 @@ public: /// \brief Prepare this symbol to be redefined. void redefineIfPossible() { if (IsRedefinable) { - Value = nullptr; - Section = nullptr; + if (SymbolContents == SymContentsVariable) { + Value = nullptr; + SymbolContents = SymContentsUnset; + } + setUndefined(); IsRedefinable = false; } } @@ -253,28 +260,40 @@ public: /// isAbsolute - Check if this is an absolute symbol. bool isAbsolute() const { return getSectionPtr() == AbsolutePseudoSection; } - /// getSection - Get the section associated with a defined, non-absolute - /// symbol. - const MCSection &getSection() const { + /// Get the section associated with a defined, non-absolute symbol. + MCSection &getSection() const { assert(isInSection() && "Invalid accessor!"); return *getSectionPtr(); } - /// setSection - Mark the symbol as defined in the section \p S. - void setSection(const MCSection &S) { + /// Mark the symbol as defined in the section \p S. + void setSection(MCSection &S) { assert(!isVariable() && "Cannot set section of variable"); - Section = &S; + assert(!SectionOrFragmentAndHasName.getPointer().is() && + "Section or null expected"); + SectionOrFragmentAndHasName.setPointer(&S); + } + + /// Mark the symbol as undefined. + void setUndefined() { + SectionOrFragmentAndHasName.setPointer( + PointerUnion()); } - /// setUndefined - Mark the symbol as undefined. - void setUndefined() { Section = nullptr; } + bool isELF() const { return Kind == SymbolKindELF; } + + bool isCOFF() const { return Kind == SymbolKindCOFF; } + + bool isMachO() const { return Kind == SymbolKindMachO; } /// @} /// \name Variable Symbols /// @{ /// isVariable - Check if this is a variable symbol. - bool isVariable() const { return Value != nullptr; } + bool isVariable() const { + return SymbolContents == SymContentsVariable; + } /// getVariableValue() - Get the value for variable symbols. const MCExpr *getVariableValue() const { @@ -287,15 +306,117 @@ public: /// @} + /// Get the (implementation defined) index. + uint32_t getIndex() const { + return Index; + } + + /// Set the (implementation defined) index. + void setIndex(uint32_t Value) const { + Index = Value; + } + + uint64_t getOffset() const { + assert((SymbolContents == SymContentsUnset || + SymbolContents == SymContentsOffset) && + "Cannot get offset for a common/variable symbol"); + return Offset; + } + void setOffset(uint64_t Value) { + assert((SymbolContents == SymContentsUnset || + SymbolContents == SymContentsOffset) && + "Cannot set offset for a common/variable symbol"); + Offset = Value; + SymbolContents = SymContentsOffset; + } + + /// Return the size of a 'common' symbol. + uint64_t getCommonSize() const { + assert(isCommon() && "Not a 'common' symbol!"); + return CommonSize; + } + + /// 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; + SymbolContents = SymContentsCommon; + + assert((!Align || isPowerOf2_32(Align)) && + "Alignment must be a power of 2"); + unsigned Log2Align = Log2_32(Align) + 1; + assert(Log2Align < (1U << NumCommonAlignmentBits) && + "Out of range alignment"); + CommonAlignLog2 = Log2Align; + } + + /// Return the alignment of a 'common' symbol. + unsigned getCommonAlignment() const { + assert(isCommon() && "Not a 'common' symbol!"); + return CommonAlignLog2 ? (1U << (CommonAlignLog2 - 1)) : 0; + } + + /// Declare this symbol as being 'common'. + /// + /// \param Size - The size of the symbol. + /// \param Align - The alignment of the symbol. + /// \return True if symbol was already declared as a different type + bool declareCommon(uint64_t Size, unsigned Align) { + assert(isCommon() || getOffset() == 0); + if(isCommon()) { + if(CommonSize != Size || getCommonAlignment() != Align) + return true; + } else + setCommon(Size, Align); + return false; + } + + /// Is this a 'common' symbol. + bool isCommon() const { + return SymbolContents == SymContentsCommon; + } + + MCFragment *getFragment() const { + return SectionOrFragmentAndHasName.getPointer().dyn_cast(); + } + void setFragment(MCFragment *Value) const { + SectionOrFragmentAndHasName.setPointer(Value); + } + + bool isExternal() const { return IsExternal; } + void setExternal(bool Value) const { IsExternal = Value; } + + bool isPrivateExtern() const { return IsPrivateExtern; } + void setPrivateExtern(bool Value) { IsPrivateExtern = Value; } + /// print - Print the value to the stream \p OS. - void print(raw_ostream &OS) const; + void print(raw_ostream &OS, const MCAsmInfo *MAI) const; /// dump - Print the value to stderr. void dump() const; + +protected: + /// Get the (implementation defined) symbol flags. + uint32_t getFlags() const { return Flags; } + + /// Set the (implementation defined) symbol flags. + void setFlags(uint32_t Value) const { + assert(Value < (1U << NumFlagsBits) && "Out of range flags"); + Flags = Value; + } + + /// Modify the flags via a mask + void modifyFlags(uint32_t Value, uint32_t Mask) const { + assert(Value < (1U << NumFlagsBits) && "Out of range flags"); + Flags = (Flags & ~Mask) | Value; + } }; inline raw_ostream &operator<<(raw_ostream &OS, const MCSymbol &Sym) { - Sym.print(OS); + Sym.print(OS, nullptr); return OS; } } // end namespace llvm