1 //===- MCSectionMachO.h - MachO Machine Code Sections -----------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file declares the MCSectionMachO class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_MC_MCSECTIONMACHO_H 15 #define LLVM_MC_MCSECTIONMACHO_H 16 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/MC/MCSection.h" 19 20 namespace llvm { 21 22 /// MCSectionMachO - This represents a section on a Mach-O system (used by 23 /// Mac OS X). On a Mac system, these are also described in 24 /// /usr/include/mach-o/loader.h. 25 class MCSectionMachO : public MCSection { 26 char SegmentName[16]; // Not necessarily null terminated! 27 char SectionName[16]; // Not necessarily null terminated! 28 29 /// TypeAndAttributes - This is the SECTION_TYPE and SECTION_ATTRIBUTES 30 /// field of a section, drawn from the enums below. 31 unsigned TypeAndAttributes; 32 33 /// Reserved2 - The 'reserved2' field of a section, used to represent the 34 /// size of stubs, for example. 35 unsigned Reserved2; 36 37 MCSectionMachO(StringRef Segment, StringRef Section, 38 unsigned TAA, unsigned reserved2, SectionKind K); 39 friend class MCContext; 40 public: 41 42 /// These are the section type and attributes fields. A MachO section can 43 /// have only one Type, but can have any of the attributes specified. 44 enum { 45 // TypeAndAttributes bitmasks. 46 SECTION_TYPE = 0x000000FFU, 47 SECTION_ATTRIBUTES = 0xFFFFFF00U, 48 49 // Valid section types. 50 51 /// S_REGULAR - Regular section. 52 S_REGULAR = 0x00U, 53 /// S_ZEROFILL - Zero fill on demand section. 54 S_ZEROFILL = 0x01U, 55 /// S_CSTRING_LITERALS - Section with literal C strings. 56 S_CSTRING_LITERALS = 0x02U, 57 /// S_4BYTE_LITERALS - Section with 4 byte literals. 58 S_4BYTE_LITERALS = 0x03U, 59 /// S_8BYTE_LITERALS - Section with 8 byte literals. 60 S_8BYTE_LITERALS = 0x04U, 61 /// S_LITERAL_POINTERS - Section with pointers to literals. 62 S_LITERAL_POINTERS = 0x05U, 63 /// S_NON_LAZY_SYMBOL_POINTERS - Section with non-lazy symbol pointers. 64 S_NON_LAZY_SYMBOL_POINTERS = 0x06U, 65 /// S_LAZY_SYMBOL_POINTERS - Section with lazy symbol pointers. 66 S_LAZY_SYMBOL_POINTERS = 0x07U, 67 /// S_SYMBOL_STUBS - Section with symbol stubs, byte size of stub in 68 /// the Reserved2 field. 69 S_SYMBOL_STUBS = 0x08U, 70 /// S_MOD_INIT_FUNC_POINTERS - Section with only function pointers for 71 /// initialization. 72 S_MOD_INIT_FUNC_POINTERS = 0x09U, 73 /// S_MOD_TERM_FUNC_POINTERS - Section with only function pointers for 74 /// termination. 75 S_MOD_TERM_FUNC_POINTERS = 0x0AU, 76 /// S_COALESCED - Section contains symbols that are to be coalesced. 77 S_COALESCED = 0x0BU, 78 /// S_GB_ZEROFILL - Zero fill on demand section (that can be larger than 4 79 /// gigabytes). 80 S_GB_ZEROFILL = 0x0CU, 81 /// S_INTERPOSING - Section with only pairs of function pointers for 82 /// interposing. 83 S_INTERPOSING = 0x0DU, 84 /// S_16BYTE_LITERALS - Section with only 16 byte literals. 85 S_16BYTE_LITERALS = 0x0EU, 86 /// S_DTRACE_DOF - Section contains DTrace Object Format. 87 S_DTRACE_DOF = 0x0FU, 88 /// S_LAZY_DYLIB_SYMBOL_POINTERS - Section with lazy symbol pointers to 89 /// lazy loaded dylibs. 90 S_LAZY_DYLIB_SYMBOL_POINTERS = 0x10U, 91 /// S_THREAD_LOCAL_REGULAR - Section with .... 92 S_THREAD_LOCAL_REGULAR = 0x11U, 93 /// S_THREAD_LOCAL_ZEROFILL - Thread local zerofill section. 94 S_THREAD_LOCAL_ZEROFILL = 0x12U, 95 /// S_THREAD_LOCAL_VARIABLES - Section with thread local variable structure 96 /// data. 97 S_THREAD_LOCAL_VARIABLES = 0x13U, 98 /// S_THREAD_LOCAL_VARIABLE_POINTERS - Section with .... 99 S_THREAD_LOCAL_VARIABLE_POINTERS = 0x14U, 100 /// S_THREAD_LOCAL_INIT_FUNCTION_POINTERS - Section with thread local 101 /// variable initialization pointers to functions. 102 S_THREAD_LOCAL_INIT_FUNCTION_POINTERS = 0x15U, 103 104 LAST_KNOWN_SECTION_TYPE = S_THREAD_LOCAL_INIT_FUNCTION_POINTERS, 105 106 107 // Valid section attributes. 108 109 /// S_ATTR_PURE_INSTRUCTIONS - Section contains only true machine 110 /// instructions. 111 S_ATTR_PURE_INSTRUCTIONS = 1U << 31, 112 /// S_ATTR_NO_TOC - Section contains coalesced symbols that are not to be 113 /// in a ranlib table of contents. 114 S_ATTR_NO_TOC = 1U << 30, 115 /// S_ATTR_STRIP_STATIC_SYMS - Ok to strip static symbols in this section 116 /// in files with the MY_DYLDLINK flag. 117 S_ATTR_STRIP_STATIC_SYMS = 1U << 29, 118 /// S_ATTR_NO_DEAD_STRIP - No dead stripping. 119 S_ATTR_NO_DEAD_STRIP = 1U << 28, 120 /// S_ATTR_LIVE_SUPPORT - Blocks are live if they reference live blocks. 121 S_ATTR_LIVE_SUPPORT = 1U << 27, 122 /// S_ATTR_SELF_MODIFYING_CODE - Used with i386 code stubs written on by 123 /// dyld. 124 S_ATTR_SELF_MODIFYING_CODE = 1U << 26, 125 /// S_ATTR_DEBUG - A debug section. 126 S_ATTR_DEBUG = 1U << 25, 127 /// S_ATTR_SOME_INSTRUCTIONS - Section contains some machine instructions. 128 S_ATTR_SOME_INSTRUCTIONS = 1U << 10, 129 /// S_ATTR_EXT_RELOC - Section has external relocation entries. 130 S_ATTR_EXT_RELOC = 1U << 9, 131 /// S_ATTR_LOC_RELOC - Section has local relocation entries. 132 S_ATTR_LOC_RELOC = 1U << 8 133 }; 134 135 StringRef getSegmentName() const { 136 // SegmentName is not necessarily null terminated! 137 if (SegmentName[15]) 138 return StringRef(SegmentName, 16); 139 return StringRef(SegmentName); 140 } 141 StringRef getSectionName() const { 142 // SectionName is not necessarily null terminated! 143 if (SectionName[15]) 144 return StringRef(SectionName, 16); 145 return StringRef(SectionName); 146 } 147 148 virtual std::string getLabelBeginName() const { 149 return StringRef(getSegmentName().str() + getSectionName().str() + "_begin"); 150 } 151 152 virtual std::string getLabelEndName() const { 153 return StringRef(getSegmentName().str() + getSectionName().str() + "_end"); 154 } 155 156 unsigned getTypeAndAttributes() const { return TypeAndAttributes; } 157 unsigned getStubSize() const { return Reserved2; } 158 159 unsigned getType() const { return TypeAndAttributes & SECTION_TYPE; } 160 bool hasAttribute(unsigned Value) const { 161 return (TypeAndAttributes & Value) != 0; 162 } 163 164 /// ParseSectionSpecifier - Parse the section specifier indicated by "Spec". 165 /// This is a string that can appear after a .section directive in a mach-o 166 /// flavored .s file. If successful, this fills in the specified Out 167 /// parameters and returns an empty string. When an invalid section 168 /// specifier is present, this returns a string indicating the problem. 169 /// If no TAA was parsed, TAA is not altered, and TAAWasSet becomes false. 170 static std::string ParseSectionSpecifier(StringRef Spec, // In. 171 StringRef &Segment, // Out. 172 StringRef &Section, // Out. 173 unsigned &TAA, // Out. 174 bool &TAAParsed, // Out. 175 unsigned &StubSize); // Out. 176 177 virtual void PrintSwitchToSection(const MCAsmInfo &MAI, 178 raw_ostream &OS, 179 const MCExpr *Subsection) const; 180 virtual bool UseCodeAlign() const; 181 virtual bool isVirtualSection() const; 182 183 static bool classof(const MCSection *S) { 184 return S->getVariant() == SV_MachO; 185 } 186 }; 187 188 } // end namespace llvm 189 190 #endif 191
