1 //===- lib/MC/MCSectionXCOFF.cpp - XCOFF Code Section Representation ------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/MC/MCSectionXCOFF.h" 10 #include "llvm/MC/MCAsmInfo.h" 11 #include "llvm/Support/Format.h" 12 #include "llvm/Support/raw_ostream.h" 13 namespace llvm { 14 class MCExpr; 15 class Triple; 16 } // namespace llvm 17 18 using namespace llvm; 19 20 MCSectionXCOFF::~MCSectionXCOFF() = default; 21 22 void MCSectionXCOFF::printCsectDirective(raw_ostream &OS) const { 23 OS << "\t.csect " << QualName->getName() << "," << Log2(getAlign()) << '\n'; 24 } 25 26 void MCSectionXCOFF::printSwitchToSection(const MCAsmInfo &MAI, const Triple &T, 27 raw_ostream &OS, 28 const MCExpr *Subsection) const { 29 if (getKind().isText()) { 30 if (getMappingClass() != XCOFF::XMC_PR) 31 report_fatal_error("Unhandled storage-mapping class for .text csect"); 32 33 printCsectDirective(OS); 34 return; 35 } 36 37 if (getKind().isReadOnly()) { 38 if (getMappingClass() != XCOFF::XMC_RO && 39 getMappingClass() != XCOFF::XMC_TD) 40 report_fatal_error("Unhandled storage-mapping class for .rodata csect."); 41 printCsectDirective(OS); 42 return; 43 } 44 45 if (getKind().isReadOnlyWithRel()) { 46 if (getMappingClass() != XCOFF::XMC_RW && 47 getMappingClass() != XCOFF::XMC_RO && 48 getMappingClass() != XCOFF::XMC_TD) 49 report_fatal_error( 50 "Unexepected storage-mapping class for ReadOnlyWithRel kind"); 51 printCsectDirective(OS); 52 return; 53 } 54 55 // Initialized TLS data. 56 if (getKind().isThreadData()) { 57 // We only expect XMC_TL here for initialized TLS data. 58 if (getMappingClass() != XCOFF::XMC_TL) 59 report_fatal_error("Unhandled storage-mapping class for .tdata csect."); 60 printCsectDirective(OS); 61 return; 62 } 63 64 if (getKind().isData()) { 65 switch (getMappingClass()) { 66 case XCOFF::XMC_RW: 67 case XCOFF::XMC_DS: 68 case XCOFF::XMC_TD: 69 printCsectDirective(OS); 70 break; 71 case XCOFF::XMC_TC: 72 case XCOFF::XMC_TE: 73 break; 74 case XCOFF::XMC_TC0: 75 OS << "\t.toc\n"; 76 break; 77 default: 78 report_fatal_error( 79 "Unhandled storage-mapping class for .data csect."); 80 } 81 return; 82 } 83 84 if (isCsect() && getMappingClass() == XCOFF::XMC_TD) { 85 assert((getKind().isBSSExtern() || getKind().isBSSLocal()) && 86 "Unexepected section kind for toc-data"); 87 printCsectDirective(OS); 88 return; 89 } 90 // Common csect type (uninitialized storage) does not have to print csect 91 // directive for section switching. 92 if (isCsect() && getCSectType() == XCOFF::XTY_CM) { 93 assert((getMappingClass() == XCOFF::XMC_RW || 94 getMappingClass() == XCOFF::XMC_BS || 95 getMappingClass() == XCOFF::XMC_UL) && 96 "Generated a storage-mapping class for a common/bss/tbss csect we " 97 "don't " 98 "understand how to switch to."); 99 // Common symbols and local zero-initialized symbols for TLS and Non-TLS are 100 // eligible for .bss/.tbss csect, getKind().isThreadBSS() is used to cover 101 // TLS common and zero-initialized local symbols since linkage type (in the 102 // GlobalVariable) is not accessible in this class. 103 assert((getKind().isBSSLocal() || getKind().isCommon() || 104 getKind().isThreadBSS()) && 105 "wrong symbol type for .bss/.tbss csect"); 106 // Don't have to print a directive for switching to section for commons and 107 // zero-initialized TLS data. The '.comm' and '.lcomm' directives of the 108 // variable will create the needed csect. 109 return; 110 } 111 112 // Zero-initialized TLS data with weak or external linkage are not eligible to 113 // be put into common csect. 114 if (getKind().isThreadBSS()) { 115 printCsectDirective(OS); 116 return; 117 } 118 119 // XCOFF debug sections. 120 if (getKind().isMetadata() && isDwarfSect()) { 121 OS << "\n\t.dwsect " << format("0x%" PRIx32, *getDwarfSubtypeFlags()) 122 << '\n'; 123 OS << MAI.getPrivateLabelPrefix() << getName() << ':' << '\n'; 124 return; 125 } 126 127 report_fatal_error("Printing for this SectionKind is unimplemented."); 128 } 129 130 bool MCSectionXCOFF::useCodeAlign() const { return getKind().isText(); } 131 132 bool MCSectionXCOFF::isVirtualSection() const { 133 // DWARF sections are always not virtual. 134 if (isDwarfSect()) 135 return false; 136 assert(isCsect() && 137 "Handling for isVirtualSection not implemented for this section!"); 138 return XCOFF::XTY_CM == CsectProp->Type; 139 } 140