1 //===- lib/MC/MCSectionMachO.cpp - MachO Code Section Representation ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCSectionMachO.h"
11 #include "llvm/MC/MCContext.h"
12 #include "llvm/Support/raw_ostream.h"
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.
20 const char *AssemblerName, *EnumName;
21 } SectionTypeDescriptors[MCSectionMachO::LAST_KNOWN_SECTION_TYPE+1] = {
22 { "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
38 { 0, /*FIXME??*/ "S_LAZY_DYLIB_SYMBOL_POINTERS" }, // 0x10
39 { "thread_local_regular", "S_THREAD_LOCAL_REGULAR" }, // 0x11
40 { "thread_local_zerofill", "S_THREAD_LOCAL_ZEROFILL" }, // 0x12
41 { "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
49 /// SectionAttrDescriptors - This is an array of descriptors for section
50 /// attributes. Unlike the SectionTypeDescriptors, this is not directly indexed
51 /// by attribute, instead it is searched. The last entry has an AttrFlagEnd
55 const char *AssemblerName, *EnumName;
56 } SectionAttrDescriptors[] = {
57 #define ENTRY(ASMNAME, ENUM) \
58 { MCSectionMachO::ENUM, ASMNAME, #ENUM },
59 ENTRY("pure_instructions", S_ATTR_PURE_INSTRUCTIONS)
60 ENTRY("no_toc", S_ATTR_NO_TOC)
61 ENTRY("strip_static_syms", S_ATTR_STRIP_STATIC_SYMS)
62 ENTRY("no_dead_strip", S_ATTR_NO_DEAD_STRIP)
63 ENTRY("live_support", S_ATTR_LIVE_SUPPORT)
64 ENTRY("self_modifying_code", S_ATTR_SELF_MODIFYING_CODE)
65 ENTRY("debug", S_ATTR_DEBUG)
66 ENTRY(0 /*FIXME*/, S_ATTR_SOME_INSTRUCTIONS)
67 ENTRY(0 /*FIXME*/, S_ATTR_EXT_RELOC)
68 ENTRY(0 /*FIXME*/, S_ATTR_LOC_RELOC)
70 { 0, "none", 0 }, // used if section has no attributes but has a stub size
71 #define AttrFlagEnd 0xffffffff // non legal value, multiple attribute bits set
75 MCSectionMachO::MCSectionMachO(StringRef Segment, StringRef Section,
76 unsigned TAA, unsigned reserved2, SectionKind K)
77 : MCSection(SV_MachO, K), TypeAndAttributes(TAA), Reserved2(reserved2) {
78 assert(Segment.size() <= 16 && Section.size() <= 16 &&
79 "Segment or section string too long");
80 for (unsigned i = 0; i != 16; ++i) {
81 if (i < Segment.size())
82 SegmentName[i] = Segment[i];
86 if (i < Section.size())
87 SectionName[i] = Section[i];
93 void MCSectionMachO::PrintSwitchToSection(const MCAsmInfo &MAI,
94 raw_ostream &OS) const {
95 OS << "\t.section\t" << getSegmentName() << ',' << getSectionName();
97 // Get the section type and attributes.
98 unsigned TAA = getTypeAndAttributes();
106 unsigned SectionType = TAA & MCSectionMachO::SECTION_TYPE;
107 assert(SectionType <= MCSectionMachO::LAST_KNOWN_SECTION_TYPE &&
108 "Invalid SectionType specified!");
110 if (SectionTypeDescriptors[SectionType].AssemblerName)
111 OS << SectionTypeDescriptors[SectionType].AssemblerName;
113 OS << "<<" << SectionTypeDescriptors[SectionType].EnumName << ">>";
115 // If we don't have any attributes, we're done.
116 unsigned SectionAttrs = TAA & MCSectionMachO::SECTION_ATTRIBUTES;
117 if (SectionAttrs == 0) {
118 // If we have a S_SYMBOL_STUBS size specified, print it along with 'none' as
119 // the attribute specifier.
121 OS << ",none," << Reserved2;
126 // Check each attribute to see if we have it.
127 char Separator = ',';
128 for (unsigned i = 0; SectionAttrDescriptors[i].AttrFlag; ++i) {
129 // Check to see if we have this attribute.
130 if ((SectionAttrDescriptors[i].AttrFlag & SectionAttrs) == 0)
133 // Yep, clear it and print it.
134 SectionAttrs &= ~SectionAttrDescriptors[i].AttrFlag;
137 if (SectionAttrDescriptors[i].AssemblerName)
138 OS << SectionAttrDescriptors[i].AssemblerName;
140 OS << "<<" << SectionAttrDescriptors[i].EnumName << ">>";
144 assert(SectionAttrs == 0 && "Unknown section attributes!");
146 // If we have a S_SYMBOL_STUBS size specified, print it.
148 OS << ',' << Reserved2;
152 bool MCSectionMachO::UseCodeAlign() const {
153 return hasAttribute(MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
156 bool MCSectionMachO::isVirtualSection() const {
157 return (getType() == MCSectionMachO::S_ZEROFILL ||
158 getType() == MCSectionMachO::S_GB_ZEROFILL ||
159 getType() == MCSectionMachO::S_THREAD_LOCAL_ZEROFILL);
162 /// StripSpaces - This removes leading and trailing spaces from the StringRef.
163 static void StripSpaces(StringRef &Str) {
164 while (!Str.empty() && isspace(Str[0]))
166 while (!Str.empty() && isspace(Str.back()))
167 Str = Str.substr(0, Str.size()-1);
170 /// ParseSectionSpecifier - Parse the section specifier indicated by "Spec".
171 /// This is a string that can appear after a .section directive in a mach-o
172 /// flavored .s file. If successful, this fills in the specified Out
173 /// parameters and returns an empty string. When an invalid section
174 /// specifier is present, this returns a string indicating the problem.
175 std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec, // In.
176 StringRef &Segment, // Out.
177 StringRef &Section, // Out.
178 unsigned &TAA, // Out.
179 unsigned &StubSize) { // Out.
180 // Find the first comma.
181 std::pair<StringRef, StringRef> Comma = Spec.split(',');
183 // If there is no comma, we fail.
184 if (Comma.second.empty())
185 return "mach-o section specifier requires a segment and section "
186 "separated by a comma";
188 // Capture segment, remove leading and trailing whitespace.
189 Segment = Comma.first;
190 StripSpaces(Segment);
192 // Verify that the segment is present and not too long.
193 if (Segment.empty() || Segment.size() > 16)
194 return "mach-o section specifier requires a segment whose length is "
195 "between 1 and 16 characters";
197 // Split the section name off from any attributes if present.
198 Comma = Comma.second.split(',');
200 // Capture section, remove leading and trailing whitespace.
201 Section = Comma.first;
202 StripSpaces(Section);
204 // Verify that the section is present and not too long.
205 if (Section.empty() || Section.size() > 16)
206 return "mach-o section specifier requires a section whose length is "
207 "between 1 and 16 characters";
209 // If there is no comma after the section, we're done.
212 if (Comma.second.empty())
215 // Otherwise, we need to parse the section type and attributes.
216 Comma = Comma.second.split(',');
218 // Get the section type.
219 StringRef SectionType = Comma.first;
220 StripSpaces(SectionType);
222 // Figure out which section type it is.
224 for (TypeID = 0; TypeID !=MCSectionMachO::LAST_KNOWN_SECTION_TYPE+1; ++TypeID)
225 if (SectionTypeDescriptors[TypeID].AssemblerName &&
226 SectionType == SectionTypeDescriptors[TypeID].AssemblerName)
229 // If we didn't find the section type, reject it.
230 if (TypeID > MCSectionMachO::LAST_KNOWN_SECTION_TYPE)
231 return "mach-o section specifier uses an unknown section type";
233 // Remember the TypeID.
236 // If we have no comma after the section type, there are no attributes.
237 if (Comma.second.empty()) {
238 // S_SYMBOL_STUBS always require a symbol stub size specifier.
239 if (TAA == MCSectionMachO::S_SYMBOL_STUBS)
240 return "mach-o section specifier of type 'symbol_stubs' requires a size "
245 // Otherwise, we do have some attributes. Split off the size specifier if
247 Comma = Comma.second.split(',');
248 StringRef Attrs = Comma.first;
250 // The attribute list is a '+' separated list of attributes.
251 std::pair<StringRef, StringRef> Plus = Attrs.split('+');
254 StringRef Attr = Plus.first;
257 // Look up the attribute.
258 for (unsigned i = 0; ; ++i) {
259 if (SectionAttrDescriptors[i].AttrFlag == AttrFlagEnd)
260 return "mach-o section specifier has invalid attribute";
262 if (SectionAttrDescriptors[i].AssemblerName &&
263 Attr == SectionAttrDescriptors[i].AssemblerName) {
264 TAA |= SectionAttrDescriptors[i].AttrFlag;
269 if (Plus.second.empty()) break;
270 Plus = Plus.second.split('+');
273 // Okay, we've parsed the section attributes, see if we have a stub size spec.
274 if (Comma.second.empty()) {
275 // S_SYMBOL_STUBS always require a symbol stub size specifier.
276 if (TAA == MCSectionMachO::S_SYMBOL_STUBS)
277 return "mach-o section specifier of type 'symbol_stubs' requires a size "
282 // If we have a stub size spec, we must have a sectiontype of S_SYMBOL_STUBS.
283 if ((TAA & MCSectionMachO::SECTION_TYPE) != MCSectionMachO::S_SYMBOL_STUBS)
284 return "mach-o section specifier cannot have a stub size specified because "
285 "it does not have type 'symbol_stubs'";
287 // Okay, if we do, it must be a number.
288 StringRef StubSizeStr = Comma.second;
289 StripSpaces(StubSizeStr);
291 // Convert the stub size from a string to an integer.
292 if (StubSizeStr.getAsInteger(0, StubSize))
293 return "mach-o section specifier has a malformed stub size";