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 // Initialized TLS data. 46 if (getKind().isThreadData()) { 47 // We only expect XMC_TL here for initialized TLS data. 48 if (getMappingClass() != XCOFF::XMC_TL) 49 report_fatal_error("Unhandled storage-mapping class for .tdata csect."); 50 printCsectDirective(OS); 51 return; 52 } 53 54 if (getKind().isData()) { 55 switch (getMappingClass()) { 56 case XCOFF::XMC_RW: 57 case XCOFF::XMC_DS: 58 case XCOFF::XMC_TD: 59 printCsectDirective(OS); 60 break; 61 case XCOFF::XMC_TC: 62 case XCOFF::XMC_TE: 63 break; 64 case XCOFF::XMC_TC0: 65 OS << "\t.toc\n"; 66 break; 67 default: 68 report_fatal_error( 69 "Unhandled storage-mapping class for .data csect."); 70 } 71 return; 72 } 73 74 if (isCsect() && getMappingClass() == XCOFF::XMC_TD) { 75 assert((getKind().isBSSExtern() || getKind().isBSSLocal() || 76 getKind().isReadOnlyWithRel()) && 77 "Unexepected section kind for toc-data"); 78 printCsectDirective(OS); 79 return; 80 } 81 // Common csect type (uninitialized storage) does not have to print csect 82 // directive for section switching. 83 if (isCsect() && getCSectType() == XCOFF::XTY_CM) { 84 assert((getMappingClass() == XCOFF::XMC_RW || 85 getMappingClass() == XCOFF::XMC_BS || 86 getMappingClass() == XCOFF::XMC_UL) && 87 "Generated a storage-mapping class for a common/bss/tbss csect we " 88 "don't " 89 "understand how to switch to."); 90 // Common symbols and local zero-initialized symbols for TLS and Non-TLS are 91 // eligible for .bss/.tbss csect, getKind().isThreadBSS() is used to cover 92 // TLS common and zero-initialized local symbols since linkage type (in the 93 // GlobalVariable) is not accessible in this class. 94 assert((getKind().isBSSLocal() || getKind().isCommon() || 95 getKind().isThreadBSS()) && 96 "wrong symbol type for .bss/.tbss csect"); 97 // Don't have to print a directive for switching to section for commons and 98 // zero-initialized TLS data. The '.comm' and '.lcomm' directives of the 99 // variable will create the needed csect. 100 return; 101 } 102 103 // Zero-initialized TLS data with weak or external linkage are not eligible to 104 // be put into common csect. 105 if (getKind().isThreadBSS()) { 106 printCsectDirective(OS); 107 return; 108 } 109 110 // XCOFF debug sections. 111 if (getKind().isMetadata() && isDwarfSect()) { 112 OS << "\n\t.dwsect " << format("0x%" PRIx32, *getDwarfSubtypeFlags()) 113 << '\n'; 114 OS << MAI.getPrivateLabelPrefix() << getName() << ':' << '\n'; 115 return; 116 } 117 118 report_fatal_error("Printing for this SectionKind is unimplemented."); 119 } 120 121 bool MCSectionXCOFF::useCodeAlign() const { return getKind().isText(); } 122 123 bool MCSectionXCOFF::isVirtualSection() const { 124 // DWARF sections are always not virtual. 125 if (isDwarfSect()) 126 return false; 127 assert(isCsect() && 128 "Handling for isVirtualSection not implemented for this section!"); 129 return XCOFF::XTY_CM == CsectProp->Type; 130 } 131