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"
13namespace llvm {
14class MCExpr;
15class Triple;
16} // namespace llvm
17
18using namespace llvm;
19
20MCSectionXCOFF::~MCSectionXCOFF() = default;
21
22void MCSectionXCOFF::printCsectDirective(raw_ostream &OS) const {
23  OS << "\t.csect " << QualName->getName() << "," << Log2(getAlign()) << '\n';
24}
25
26void 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
130bool MCSectionXCOFF::useCodeAlign() const { return getKind().isText(); }
131
132bool 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