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();
104 unsigned SectionType = TAA & MCSectionMachO::SECTION_TYPE;
105 assert(SectionType <= MCSectionMachO::LAST_KNOWN_SECTION_TYPE &&
106 "Invalid SectionType specified!");
108 if (SectionTypeDescriptors[SectionType].AssemblerName) {
110 OS << SectionTypeDescriptors[SectionType].AssemblerName;
112 // If we have no name for the attribute, stop here.
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 = ',';
129 SectionAttrs != 0 && SectionAttrDescriptors[i].AttrFlag;
131 // Check to see if we have this attribute.
132 if ((SectionAttrDescriptors[i].AttrFlag & SectionAttrs) == 0)
135 // Yep, clear it and print it.
136 SectionAttrs &= ~SectionAttrDescriptors[i].AttrFlag;
139 if (SectionAttrDescriptors[i].AssemblerName)
140 OS << SectionAttrDescriptors[i].AssemblerName;
142 OS << "<<" << SectionAttrDescriptors[i].EnumName << ">>";
146 assert(SectionAttrs == 0 && "Unknown section attributes!");
148 // If we have a S_SYMBOL_STUBS size specified, print it.
150 OS << ',' << Reserved2;
154 bool MCSectionMachO::UseCodeAlign() const {
155 return hasAttribute(MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS);
158 bool MCSectionMachO::isVirtualSection() const {
159 return (getType() == MCSectionMachO::S_ZEROFILL ||
160 getType() == MCSectionMachO::S_GB_ZEROFILL ||
161 getType() == MCSectionMachO::S_THREAD_LOCAL_ZEROFILL);
164 /// StripSpaces - This removes leading and trailing spaces from the StringRef.
165 static void StripSpaces(StringRef &Str) {
166 while (!Str.empty() && isspace(Str[0]))
168 while (!Str.empty() && isspace(Str.back()))
169 Str = Str.substr(0, Str.size()-1);
172 /// ParseSectionSpecifier - Parse the section specifier indicated by "Spec".
173 /// This is a string that can appear after a .section directive in a mach-o
174 /// flavored .s file. If successful, this fills in the specified Out
175 /// parameters and returns an empty string. When an invalid section
176 /// specifier is present, this returns a string indicating the problem.
177 std::string MCSectionMachO::ParseSectionSpecifier(StringRef Spec, // In.
178 StringRef &Segment, // Out.
179 StringRef &Section, // Out.
180 unsigned &TAA, // Out.
181 unsigned &StubSize) { // Out.
182 // Find the first comma.
183 std::pair<StringRef, StringRef> Comma = Spec.split(',');
185 // If there is no comma, we fail.
186 if (Comma.second.empty())
187 return "mach-o section specifier requires a segment and section "
188 "separated by a comma";
190 // Capture segment, remove leading and trailing whitespace.
191 Segment = Comma.first;
192 StripSpaces(Segment);
194 // Verify that the segment is present and not too long.
195 if (Segment.empty() || Segment.size() > 16)
196 return "mach-o section specifier requires a segment whose length is "
197 "between 1 and 16 characters";
199 // Split the section name off from any attributes if present.
200 Comma = Comma.second.split(',');
202 // Capture section, remove leading and trailing whitespace.
203 Section = Comma.first;
204 StripSpaces(Section);
206 // Verify that the section is present and not too long.
207 if (Section.empty() || Section.size() > 16)
208 return "mach-o section specifier requires a section whose length is "
209 "between 1 and 16 characters";
211 // If there is no comma after the section, we're done.
213 if (Comma.second.empty())
216 // Otherwise, we need to parse the section type and attributes.
217 Comma = Comma.second.split(',');
219 // Get the section type.
220 StringRef SectionType = Comma.first;
221 StripSpaces(SectionType);
223 // Figure out which section type it is.
225 for (TypeID = 0; TypeID !=MCSectionMachO::LAST_KNOWN_SECTION_TYPE+1; ++TypeID)
226 if (SectionTypeDescriptors[TypeID].AssemblerName &&
227 SectionType == SectionTypeDescriptors[TypeID].AssemblerName)
230 // If we didn't find the section type, reject it.
231 if (TypeID > MCSectionMachO::LAST_KNOWN_SECTION_TYPE)
232 return "mach-o section specifier uses an unknown section type";
234 // Remember the TypeID.
237 // If we have no comma after the section type, there are no attributes.
238 if (Comma.second.empty()) {
239 // S_SYMBOL_STUBS always require a symbol stub size specifier.
240 if (TAA == MCSectionMachO::S_SYMBOL_STUBS)
241 return "mach-o section specifier of type 'symbol_stubs' requires a size "
246 // Otherwise, we do have some attributes. Split off the size specifier if
248 Comma = Comma.second.split(',');
249 StringRef Attrs = Comma.first;
251 // The attribute list is a '+' separated list of attributes.
252 std::pair<StringRef, StringRef> Plus = Attrs.split('+');
255 StringRef Attr = Plus.first;
258 // Look up the attribute.
259 for (unsigned i = 0; ; ++i) {
260 if (SectionAttrDescriptors[i].AttrFlag == AttrFlagEnd)
261 return "mach-o section specifier has invalid attribute";
263 if (SectionAttrDescriptors[i].AssemblerName &&
264 Attr == SectionAttrDescriptors[i].AssemblerName) {
265 TAA |= SectionAttrDescriptors[i].AttrFlag;
270 if (Plus.second.empty()) break;
271 Plus = Plus.second.split('+');
274 // Okay, we've parsed the section attributes, see if we have a stub size spec.
275 if (Comma.second.empty()) {
276 // S_SYMBOL_STUBS always require a symbol stub size specifier.
277 if (TAA == MCSectionMachO::S_SYMBOL_STUBS)
278 return "mach-o section specifier of type 'symbol_stubs' requires a size "
283 // If we have a stub size spec, we must have a sectiontype of S_SYMBOL_STUBS.
284 if ((TAA & MCSectionMachO::SECTION_TYPE) != MCSectionMachO::S_SYMBOL_STUBS)
285 return "mach-o section specifier cannot have a stub size specified because "
286 "it does not have type 'symbol_stubs'";
288 // Okay, if we do, it must be a number.
289 StringRef StubSizeStr = Comma.second;
290 StripSpaces(StubSizeStr);
292 // Convert the stub size from a string to an integer.
293 if (StubSizeStr.getAsInteger(0, StubSize))
294 return "mach-o section specifier has a malformed stub size";