diff options
| -rw-r--r-- | llvm/include/llvm/MC/MCSymbol.h | 28 | ||||
| -rw-r--r-- | llvm/lib/MC/MCSymbol.cpp | 2 |
2 files changed, 21 insertions, 9 deletions
diff --git a/llvm/include/llvm/MC/MCSymbol.h b/llvm/include/llvm/MC/MCSymbol.h index 48b50d9ada1..e52a34601b0 100644 --- a/llvm/include/llvm/MC/MCSymbol.h +++ b/llvm/include/llvm/MC/MCSymbol.h @@ -109,6 +109,14 @@ protected: /// 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. + static const unsigned NumCommonAlignmentBits = 5; + unsigned CommonAlignLog2 : NumCommonAlignmentBits; + /// Index field, for use by the object file implementation. mutable uint32_t Index = 0; @@ -123,11 +131,6 @@ protected: const MCExpr *Value; }; - /// The alignment of the symbol, if it is 'common', or -1. - // - // FIXME: Pack this in with other fields? - unsigned CommonAlign = -1U; - /// The Flags field is used by object file implementations to store /// additional per symbol information which is not easily classified. mutable uint32_t Flags = 0; @@ -148,7 +151,8 @@ protected: // MCContext creates and uniques these. MCSymbol(SymbolKind Kind, const StringMapEntry<bool> *Name, bool isTemporary) : IsTemporary(isTemporary), IsRedefinable(false), IsUsed(false), IsRegistered(false), IsExternal(false), IsPrivateExtern(false), - Kind(Kind), IsUsedInReloc(false), SymbolContents(SymContentsUnset) { + Kind(Kind), IsUsedInReloc(false), SymbolContents(SymContentsUnset), + CommonAlignLog2(0) { Offset = 0; SectionOrFragmentAndHasName.setInt(!!Name); if (Name) @@ -338,14 +342,20 @@ public: void setCommon(uint64_t Size, unsigned Align) { assert(getOffset() == 0); CommonSize = Size; - CommonAlign = Align; 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 CommonAlign; + return CommonAlignLog2 ? (1U << (CommonAlignLog2 - 1)) : 0; } /// Declare this symbol as being 'common'. @@ -356,7 +366,7 @@ public: bool declareCommon(uint64_t Size, unsigned Align) { assert(isCommon() || getOffset() == 0); if(isCommon()) { - if(CommonSize != Size || CommonAlign != Align) + if(CommonSize != Size || getCommonAlignment() != Align) return true; } else setCommon(Size, Align); diff --git a/llvm/lib/MC/MCSymbol.cpp b/llvm/lib/MC/MCSymbol.cpp index 125380a9d14..2655a181a23 100644 --- a/llvm/lib/MC/MCSymbol.cpp +++ b/llvm/lib/MC/MCSymbol.cpp @@ -19,6 +19,8 @@ using namespace llvm; // Sentinel value for the absolute pseudo section. MCSection *MCSymbol::AbsolutePseudoSection = reinterpret_cast<MCSection *>(1); +const unsigned MCSymbol::NumCommonAlignmentBits; + void *MCSymbol::operator new(size_t s, const StringMapEntry<bool> *Name, MCContext &Ctx) { // We may need more space for a Name to account for alignment. So allocate |
