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Chris Lattner6c203912009-08-10 18:15:01 +00001//===- lib/MC/MCSectionMachO.cpp - MachO Code Section Representation ------===//
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#include "llvm/MC/MCSectionMachO.h"
11#include "llvm/MC/MCContext.h"
12#include "llvm/Support/raw_ostream.h"
Nick Lewycky0de20af2010-12-19 20:43:38 +000013#include <cctype>
Chris Lattner6c203912009-08-10 18:15:01 +000014using namespace llvm;
15
16/// SectionTypeDescriptors - These are strings that describe the various section
17/// types. This *must* be kept in order with and stay synchronized with the
18/// section type list.
19static const struct {
20 const char *AssemblerName, *EnumName;
David Majnemer7b583052014-03-07 07:36:05 +000021} SectionTypeDescriptors[MachO::LAST_KNOWN_SECTION_TYPE+1] = {
Chris Lattner6c203912009-08-10 18:15:01 +000022 { "regular", "S_REGULAR" }, // 0x00
23 { 0, "S_ZEROFILL" }, // 0x01
24 { "cstring_literals", "S_CSTRING_LITERALS" }, // 0x02
25 { "4byte_literals", "S_4BYTE_LITERALS" }, // 0x03
26 { "8byte_literals", "S_8BYTE_LITERALS" }, // 0x04
27 { "literal_pointers", "S_LITERAL_POINTERS" }, // 0x05
28 { "non_lazy_symbol_pointers", "S_NON_LAZY_SYMBOL_POINTERS" }, // 0x06
29 { "lazy_symbol_pointers", "S_LAZY_SYMBOL_POINTERS" }, // 0x07
30 { "symbol_stubs", "S_SYMBOL_STUBS" }, // 0x08
31 { "mod_init_funcs", "S_MOD_INIT_FUNC_POINTERS" }, // 0x09
32 { "mod_term_funcs", "S_MOD_TERM_FUNC_POINTERS" }, // 0x0A
33 { "coalesced", "S_COALESCED" }, // 0x0B
34 { 0, /*FIXME??*/ "S_GB_ZEROFILL" }, // 0x0C
35 { "interposing", "S_INTERPOSING" }, // 0x0D
36 { "16byte_literals", "S_16BYTE_LITERALS" }, // 0x0E
37 { 0, /*FIXME??*/ "S_DTRACE_DOF" }, // 0x0F
Eric Christopherbf792382010-05-17 21:02:07 +000038 { 0, /*FIXME??*/ "S_LAZY_DYLIB_SYMBOL_POINTERS" }, // 0x10
39 { "thread_local_regular", "S_THREAD_LOCAL_REGULAR" }, // 0x11
Eric Christopher3dca28d2010-05-21 21:08:52 +000040 { "thread_local_zerofill", "S_THREAD_LOCAL_ZEROFILL" }, // 0x12
Eric Christopherbf792382010-05-17 21:02:07 +000041 { "thread_local_variables", "S_THREAD_LOCAL_VARIABLES" }, // 0x13
42 { "thread_local_variable_pointers",
43 "S_THREAD_LOCAL_VARIABLE_POINTERS" }, // 0x14
44 { "thread_local_init_function_pointers",
45 "S_THREAD_LOCAL_INIT_FUNCTION_POINTERS"}, // 0x15
Chris Lattner6c203912009-08-10 18:15:01 +000046};
47
48
49/// SectionAttrDescriptors - This is an array of descriptors for section
50/// attributes. Unlike the SectionTypeDescriptors, this is not directly indexed
David Majnemere500ec12014-03-10 00:55:07 +000051/// by attribute, instead it is searched.
Chris Lattner6c203912009-08-10 18:15:01 +000052static const struct {
53 unsigned AttrFlag;
54 const char *AssemblerName, *EnumName;
55} SectionAttrDescriptors[] = {
56#define ENTRY(ASMNAME, ENUM) \
David Majnemer7b583052014-03-07 07:36:05 +000057 { MachO::ENUM, ASMNAME, #ENUM },
Chris Lattner6c203912009-08-10 18:15:01 +000058ENTRY("pure_instructions", S_ATTR_PURE_INSTRUCTIONS)
59ENTRY("no_toc", S_ATTR_NO_TOC)
60ENTRY("strip_static_syms", S_ATTR_STRIP_STATIC_SYMS)
61ENTRY("no_dead_strip", S_ATTR_NO_DEAD_STRIP)
62ENTRY("live_support", S_ATTR_LIVE_SUPPORT)
63ENTRY("self_modifying_code", S_ATTR_SELF_MODIFYING_CODE)
64ENTRY("debug", S_ATTR_DEBUG)
65ENTRY(0 /*FIXME*/, S_ATTR_SOME_INSTRUCTIONS)
66ENTRY(0 /*FIXME*/, S_ATTR_EXT_RELOC)
67ENTRY(0 /*FIXME*/, S_ATTR_LOC_RELOC)
68#undef ENTRY
Kevin Enderby818b6b92009-10-07 20:57:20 +000069 { 0, "none", 0 }, // used if section has no attributes but has a stub size
Chris Lattner6c203912009-08-10 18:15:01 +000070};
71
Chris Lattner5418dd52010-04-08 21:26:26 +000072MCSectionMachO::MCSectionMachO(StringRef Segment, StringRef Section,
73 unsigned TAA, unsigned reserved2, SectionKind K)
Daniel Dunbarce5e1bb2010-05-17 21:54:26 +000074 : MCSection(SV_MachO, K), TypeAndAttributes(TAA), Reserved2(reserved2) {
Chris Lattner5418dd52010-04-08 21:26:26 +000075 assert(Segment.size() <= 16 && Section.size() <= 16 &&
76 "Segment or section string too long");
77 for (unsigned i = 0; i != 16; ++i) {
78 if (i < Segment.size())
79 SegmentName[i] = Segment[i];
80 else
81 SegmentName[i] = 0;
Jim Grosbach90600d32010-10-21 22:04:05 +000082
Chris Lattner5418dd52010-04-08 21:26:26 +000083 if (i < Section.size())
84 SectionName[i] = Section[i];
85 else
86 SectionName[i] = 0;
Jim Grosbach90600d32010-10-21 22:04:05 +000087 }
Chris Lattner6c203912009-08-10 18:15:01 +000088}
89
Chris Lattnere9a75a62009-08-22 21:43:10 +000090void MCSectionMachO::PrintSwitchToSection(const MCAsmInfo &MAI,
Peter Collingbourne2f495b92013-04-17 21:18:16 +000091 raw_ostream &OS,
92 const MCExpr *Subsection) const {
Chris Lattner6c203912009-08-10 18:15:01 +000093 OS << "\t.section\t" << getSegmentName() << ',' << getSectionName();
Jim Grosbach90600d32010-10-21 22:04:05 +000094
Chris Lattner6c203912009-08-10 18:15:01 +000095 // Get the section type and attributes.
96 unsigned TAA = getTypeAndAttributes();
97 if (TAA == 0) {
98 OS << '\n';
99 return;
100 }
101
David Majnemercd481d32014-03-07 18:49:54 +0000102 MachO::SectionType SectionType = getType();
David Majnemer7b583052014-03-07 07:36:05 +0000103 assert(SectionType <= MachO::LAST_KNOWN_SECTION_TYPE &&
Chris Lattner6c203912009-08-10 18:15:01 +0000104 "Invalid SectionType specified!");
105
Stuart Hastingsb4863a42011-02-21 17:27:17 +0000106 if (SectionTypeDescriptors[SectionType].AssemblerName) {
107 OS << ',';
Chris Lattner6c203912009-08-10 18:15:01 +0000108 OS << SectionTypeDescriptors[SectionType].AssemblerName;
Stuart Hastingsd7927e02011-02-21 21:07:07 +0000109 } else {
Stuart Hastingsb4863a42011-02-21 17:27:17 +0000110 // If we have no name for the attribute, stop here.
Stuart Hastingsd7927e02011-02-21 21:07:07 +0000111 OS << '\n';
Stuart Hastingsb4863a42011-02-21 17:27:17 +0000112 return;
Stuart Hastingsd7927e02011-02-21 21:07:07 +0000113 }
Jim Grosbach90600d32010-10-21 22:04:05 +0000114
Chris Lattner6c203912009-08-10 18:15:01 +0000115 // If we don't have any attributes, we're done.
David Majnemer7b583052014-03-07 07:36:05 +0000116 unsigned SectionAttrs = TAA & MachO::SECTION_ATTRIBUTES;
Chris Lattner6c203912009-08-10 18:15:01 +0000117 if (SectionAttrs == 0) {
118 // If we have a S_SYMBOL_STUBS size specified, print it along with 'none' as
119 // the attribute specifier.
120 if (Reserved2 != 0)
121 OS << ",none," << Reserved2;
122 OS << '\n';
123 return;
124 }
125
126 // Check each attribute to see if we have it.
127 char Separator = ',';
Stuart Hastingsb4863a42011-02-21 17:27:17 +0000128 for (unsigned i = 0;
129 SectionAttrs != 0 && SectionAttrDescriptors[i].AttrFlag;
130 ++i) {
Chris Lattner6c203912009-08-10 18:15:01 +0000131 // Check to see if we have this attribute.
132 if ((SectionAttrDescriptors[i].AttrFlag & SectionAttrs) == 0)
133 continue;
Jim Grosbach90600d32010-10-21 22:04:05 +0000134
Chris Lattner6c203912009-08-10 18:15:01 +0000135 // Yep, clear it and print it.
136 SectionAttrs &= ~SectionAttrDescriptors[i].AttrFlag;
Jim Grosbach90600d32010-10-21 22:04:05 +0000137
Chris Lattner6c203912009-08-10 18:15:01 +0000138 OS << Separator;
139 if (SectionAttrDescriptors[i].AssemblerName)
140 OS << SectionAttrDescriptors[i].AssemblerName;
141 else
142 OS << "<<" << SectionAttrDescriptors[i].EnumName << ">>";
143 Separator = '+';
144 }
Jim Grosbach90600d32010-10-21 22:04:05 +0000145
Chris Lattner6c203912009-08-10 18:15:01 +0000146 assert(SectionAttrs == 0 && "Unknown section attributes!");
Jim Grosbach90600d32010-10-21 22:04:05 +0000147
Chris Lattner6c203912009-08-10 18:15:01 +0000148 // If we have a S_SYMBOL_STUBS size specified, print it.
149 if (Reserved2 != 0)
150 OS << ',' << Reserved2;
151 OS << '\n';
152}
153
Jan Wen Voung87f77b52010-10-04 17:32:41 +0000154bool MCSectionMachO::UseCodeAlign() const {
David Majnemer7b583052014-03-07 07:36:05 +0000155 return hasAttribute(MachO::S_ATTR_PURE_INSTRUCTIONS);
Jan Wen Voung87f77b52010-10-04 17:32:41 +0000156}
157
Rafael Espindola7a2cd8b2010-11-17 20:03:54 +0000158bool MCSectionMachO::isVirtualSection() const {
David Majnemer7b583052014-03-07 07:36:05 +0000159 return (getType() == MachO::S_ZEROFILL ||
160 getType() == MachO::S_GB_ZEROFILL ||
161 getType() == MachO::S_THREAD_LOCAL_ZEROFILL);
Rafael Espindola7a2cd8b2010-11-17 20:03:54 +0000162}
163
Chris Lattner6c203912009-08-10 18:15:01 +0000164/// 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.
169std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec, // In.
170 StringRef &Segment, // Out.
171 StringRef &Section, // Out.
172 unsigned &TAA, // Out.
Stuart Hastings12d53122011-03-19 02:42:31 +0000173 bool &TAAParsed, // Out.
Chris Lattner6c203912009-08-10 18:15:01 +0000174 unsigned &StubSize) { // Out.
Stuart Hastings12d53122011-03-19 02:42:31 +0000175 TAAParsed = false;
Jim Grosbach90600d32010-10-21 22:04:05 +0000176
David Majnemere500ec12014-03-10 00:55:07 +0000177 SmallVector<StringRef, 5> SplitSpec;
178 Spec.split(SplitSpec, ",");
179 // Remove leading and trailing whitespace.
180 auto GetEmptyOrTrim = [&SplitSpec](size_t Idx) -> StringRef {
181 return SplitSpec.size() > Idx ? SplitSpec[Idx].trim() : StringRef();
182 };
183 Segment = GetEmptyOrTrim(0);
184 Section = GetEmptyOrTrim(1);
185 StringRef SectionType = GetEmptyOrTrim(2);
186 StringRef Attrs = GetEmptyOrTrim(3);
187 StringRef StubSizeStr = GetEmptyOrTrim(4);
Chris Lattner6c203912009-08-10 18:15:01 +0000188
189 // Verify that the segment is present and not too long.
190 if (Segment.empty() || Segment.size() > 16)
191 return "mach-o section specifier requires a segment whose length is "
192 "between 1 and 16 characters";
Jim Grosbach90600d32010-10-21 22:04:05 +0000193
Chris Lattner6c203912009-08-10 18:15:01 +0000194 // Verify that the section is present and not too long.
David Majnemere500ec12014-03-10 00:55:07 +0000195 if (Section.empty())
196 return "mach-o section specifier requires a segment and section "
197 "separated by a comma";
198
199 if (Section.size() > 16)
Chris Lattner6c203912009-08-10 18:15:01 +0000200 return "mach-o section specifier requires a section whose length is "
201 "between 1 and 16 characters";
202
203 // If there is no comma after the section, we're done.
Stuart Hastings12d53122011-03-19 02:42:31 +0000204 TAA = 0;
Chris Lattner6c203912009-08-10 18:15:01 +0000205 StubSize = 0;
David Majnemere500ec12014-03-10 00:55:07 +0000206 if (SectionType.empty())
Chris Lattner6c203912009-08-10 18:15:01 +0000207 return "";
Jim Grosbach90600d32010-10-21 22:04:05 +0000208
Chris Lattner6c203912009-08-10 18:15:01 +0000209 // Figure out which section type it is.
David Majnemere500ec12014-03-10 00:55:07 +0000210 auto TypeDescriptor = std::find_if(
211 std::begin(SectionTypeDescriptors), std::end(SectionTypeDescriptors),
David Majnemer596587f2014-03-10 01:04:18 +0000212 [&](decltype(*SectionTypeDescriptors) &Descriptor) {
David Majnemere500ec12014-03-10 00:55:07 +0000213 return Descriptor.AssemblerName &&
214 SectionType == Descriptor.AssemblerName;
215 });
Jim Grosbach90600d32010-10-21 22:04:05 +0000216
Chris Lattner6c203912009-08-10 18:15:01 +0000217 // If we didn't find the section type, reject it.
David Majnemere500ec12014-03-10 00:55:07 +0000218 if (TypeDescriptor == std::end(SectionTypeDescriptors))
Chris Lattner6c203912009-08-10 18:15:01 +0000219 return "mach-o section specifier uses an unknown section type";
Jim Grosbach90600d32010-10-21 22:04:05 +0000220
Chris Lattner6c203912009-08-10 18:15:01 +0000221 // Remember the TypeID.
David Majnemere500ec12014-03-10 00:55:07 +0000222 TAA = TypeDescriptor - std::begin(SectionTypeDescriptors);
Stuart Hastings12d53122011-03-19 02:42:31 +0000223 TAAParsed = true;
Chris Lattner6c203912009-08-10 18:15:01 +0000224
225 // If we have no comma after the section type, there are no attributes.
David Majnemere500ec12014-03-10 00:55:07 +0000226 if (Attrs.empty()) {
Chris Lattner6c203912009-08-10 18:15:01 +0000227 // S_SYMBOL_STUBS always require a symbol stub size specifier.
David Majnemer7b583052014-03-07 07:36:05 +0000228 if (TAA == MachO::S_SYMBOL_STUBS)
Chris Lattner6c203912009-08-10 18:15:01 +0000229 return "mach-o section specifier of type 'symbol_stubs' requires a size "
230 "specifier";
231 return "";
232 }
233
Chris Lattner6c203912009-08-10 18:15:01 +0000234 // The attribute list is a '+' separated list of attributes.
David Majnemere500ec12014-03-10 00:55:07 +0000235 SmallVector<StringRef, 1> SectionAttrs;
236 Attrs.split(SectionAttrs, "+", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
Jim Grosbach90600d32010-10-21 22:04:05 +0000237
David Majnemere500ec12014-03-10 00:55:07 +0000238 for (StringRef &SectionAttr : SectionAttrs) {
239 auto AttrDescriptorI = std::find_if(
240 std::begin(SectionAttrDescriptors), std::end(SectionAttrDescriptors),
David Majnemer596587f2014-03-10 01:04:18 +0000241 [&](decltype(*SectionAttrDescriptors) &Descriptor) {
David Majnemere500ec12014-03-10 00:55:07 +0000242 return Descriptor.AssemblerName &&
243 SectionAttr.trim() == Descriptor.AssemblerName;
244 });
245 if (AttrDescriptorI == std::end(SectionAttrDescriptors))
246 return "mach-o section specifier has invalid attribute";
Chris Lattner6c203912009-08-10 18:15:01 +0000247
David Majnemere500ec12014-03-10 00:55:07 +0000248 TAA |= AttrDescriptorI->AttrFlag;
249 }
Chris Lattner6c203912009-08-10 18:15:01 +0000250
251 // Okay, we've parsed the section attributes, see if we have a stub size spec.
David Majnemere500ec12014-03-10 00:55:07 +0000252 if (StubSizeStr.empty()) {
Chris Lattner6c203912009-08-10 18:15:01 +0000253 // S_SYMBOL_STUBS always require a symbol stub size specifier.
David Majnemer7b583052014-03-07 07:36:05 +0000254 if (TAA == MachO::S_SYMBOL_STUBS)
Chris Lattner6c203912009-08-10 18:15:01 +0000255 return "mach-o section specifier of type 'symbol_stubs' requires a size "
256 "specifier";
257 return "";
258 }
259
260 // If we have a stub size spec, we must have a sectiontype of S_SYMBOL_STUBS.
David Majnemer7b583052014-03-07 07:36:05 +0000261 if ((TAA & MachO::SECTION_TYPE) != MachO::S_SYMBOL_STUBS)
Chris Lattner6c203912009-08-10 18:15:01 +0000262 return "mach-o section specifier cannot have a stub size specified because "
263 "it does not have type 'symbol_stubs'";
Jim Grosbach90600d32010-10-21 22:04:05 +0000264
Chris Lattnera15f0042009-09-20 06:58:54 +0000265 // Convert the stub size from a string to an integer.
266 if (StubSizeStr.getAsInteger(0, StubSize))
Chris Lattner6c203912009-08-10 18:15:01 +0000267 return "mach-o section specifier has a malformed stub size";
Jim Grosbach90600d32010-10-21 22:04:05 +0000268
Chris Lattner6c203912009-08-10 18:15:01 +0000269 return "";
270}