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
printCsectDirective(raw_ostream & OS) const22 void MCSectionXCOFF::printCsectDirective(raw_ostream &OS) const {
23 OS << "\t.csect " << QualName->getName() << "," << Log2_32(getAlignment())
24 << '\n';
25 }
26
printSwitchToSection(const MCAsmInfo & MAI,const Triple & T,raw_ostream & OS,const MCExpr * Subsection) const27 void MCSectionXCOFF::printSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
28 raw_ostream &OS,
29 const MCExpr *Subsection) const {
30 if (getKind().isText()) {
31 if (getMappingClass() != XCOFF::XMC_PR)
32 report_fatal_error("Unhandled storage-mapping class for .text csect");
33
34 printCsectDirective(OS);
35 return;
36 }
37
38 if (getKind().isReadOnly()) {
39 if (getMappingClass() != XCOFF::XMC_RO &&
40 getMappingClass() != XCOFF::XMC_TD)
41 report_fatal_error("Unhandled storage-mapping class for .rodata csect.");
42 printCsectDirective(OS);
43 return;
44 }
45
46 // Initialized TLS data.
47 if (getKind().isThreadData()) {
48 // We only expect XMC_TL here for initialized TLS data.
49 if (getMappingClass() != XCOFF::XMC_TL)
50 report_fatal_error("Unhandled storage-mapping class for .tdata csect.");
51 printCsectDirective(OS);
52 return;
53 }
54
55 if (getKind().isData()) {
56 switch (getMappingClass()) {
57 case XCOFF::XMC_RW:
58 case XCOFF::XMC_DS:
59 case XCOFF::XMC_TD:
60 printCsectDirective(OS);
61 break;
62 case XCOFF::XMC_TC:
63 case XCOFF::XMC_TE:
64 break;
65 case XCOFF::XMC_TC0:
66 OS << "\t.toc\n";
67 break;
68 default:
69 report_fatal_error(
70 "Unhandled storage-mapping class for .data csect.");
71 }
72 return;
73 }
74
75 if (isCsect() && getMappingClass() == XCOFF::XMC_TD) {
76 assert((getKind().isBSSExtern() || getKind().isBSSLocal() ||
77 getKind().isReadOnlyWithRel()) &&
78 "Unexepected section kind for toc-data");
79 printCsectDirective(OS);
80 return;
81 }
82 // Common csect type (uninitialized storage) does not have to print csect
83 // directive for section switching.
84 if (isCsect() && getCSectType() == XCOFF::XTY_CM) {
85 assert((getMappingClass() == XCOFF::XMC_RW ||
86 getMappingClass() == XCOFF::XMC_BS ||
87 getMappingClass() == XCOFF::XMC_UL) &&
88 "Generated a storage-mapping class for a common/bss/tbss csect we "
89 "don't "
90 "understand how to switch to.");
91 // Common symbols and local zero-initialized symbols for TLS and Non-TLS are
92 // eligible for .bss/.tbss csect, getKind().isThreadBSS() is used to cover
93 // TLS common and zero-initialized local symbols since linkage type (in the
94 // GlobalVariable) is not accessible in this class.
95 assert((getKind().isBSSLocal() || getKind().isCommon() ||
96 getKind().isThreadBSS()) &&
97 "wrong symbol type for .bss/.tbss csect");
98 // Don't have to print a directive for switching to section for commons and
99 // zero-initialized TLS data. The '.comm' and '.lcomm' directives of the
100 // variable will create the needed csect.
101 return;
102 }
103
104 // Zero-initialized TLS data with weak or external linkage are not eligible to
105 // be put into common csect.
106 if (getKind().isThreadBSS()) {
107 printCsectDirective(OS);
108 return;
109 }
110
111 // XCOFF debug sections.
112 if (getKind().isMetadata() && isDwarfSect()) {
113 OS << "\n\t.dwsect " << format("0x%" PRIx32, getDwarfSubtypeFlags().value())
114 << '\n';
115 OS << MAI.getPrivateLabelPrefix() << getName() << ':' << '\n';
116 return;
117 }
118
119 report_fatal_error("Printing for this SectionKind is unimplemented.");
120 }
121
useCodeAlign() const122 bool MCSectionXCOFF::useCodeAlign() const { return getKind().isText(); }
123
isVirtualSection() const124 bool MCSectionXCOFF::isVirtualSection() const {
125 // DWARF sections are always not virtual.
126 if (isDwarfSect())
127 return false;
128 assert(isCsect() &&
129 "Handling for isVirtualSection not implemented for this section!");
130 return XCOFF::XTY_CM == CsectProp->Type;
131 }
132