1 //===-- TargetAsmInfo.cpp - Asm Info ---------------------------------------==//
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 // This file defines target asm properties related what form asm statements
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Constants.h"
16 #include "llvm/GlobalVariable.h"
17 #include "llvm/Function.h"
18 #include "llvm/Module.h"
19 #include "llvm/Type.h"
20 #include "llvm/Target/TargetAsmInfo.h"
21 #include "llvm/Target/TargetOptions.h"
22 #include "llvm/Support/Dwarf.h"
28 void TargetAsmInfo::fillDefaultValues() {
29 BSSSection = "\t.bss";
34 SmallRODataSection = 0;
37 ZeroFillDirective = 0;
38 NonexecutableStackDirective = 0;
45 PrivateGlobalPrefix = ".";
46 LessPrivateGlobalPrefix = "";
47 JumpTableSpecialLabelPrefix = 0;
48 GlobalVarAddrPrefix = "";
49 GlobalVarAddrSuffix = "";
50 FunctionAddrPrefix = "";
51 FunctionAddrSuffix = "";
52 PersonalityPrefix = "";
53 PersonalitySuffix = "";
54 NeedsIndirectEncoding = false;
55 InlineAsmStart = "#APP";
56 InlineAsmEnd = "#NO_APP";
58 StringConstantPrefix = ".str";
59 ZeroDirective = "\t.zero\t";
60 ZeroDirectiveSuffix = 0;
61 AsciiDirective = "\t.ascii\t";
62 AscizDirective = "\t.asciz\t";
63 Data8bitsDirective = "\t.byte\t";
64 Data16bitsDirective = "\t.short\t";
65 Data32bitsDirective = "\t.long\t";
66 Data64bitsDirective = "\t.quad\t";
67 AlignDirective = "\t.align\t";
68 AlignmentIsInBytes = true;
69 TextAlignFillValue = 0;
70 SwitchToSectionDirective = "\t.section\t";
71 TextSectionStartSuffix = "";
72 DataSectionStartSuffix = "";
73 SectionEndDirectiveSuffix = 0;
74 ConstantPoolSection = "\t.section .rodata";
75 JumpTableDataSection = "\t.section .rodata";
76 JumpTableDirective = 0;
79 // FIXME: Flags are ELFish - replace with normal section stuff.
80 StaticCtorsSection = "\t.section .ctors,\"aw\",@progbits";
81 StaticDtorsSection = "\t.section .dtors,\"aw\",@progbits";
82 GlobalDirective = "\t.globl\t";
85 COMMDirective = "\t.comm\t";
86 COMMDirectiveTakesAlignment = true;
87 HasDotTypeDotSizeDirective = true;
88 HasSingleParameterDotFile = true;
92 // FIXME: These are ELFish - move to ELFTAI.
93 HiddenDirective = "\t.hidden\t";
94 ProtectedDirective = "\t.protected\t";
95 AbsoluteDebugSectionOffsets = false;
96 AbsoluteEHSectionOffsets = false;
98 HasDotLocAndDotFile = false;
99 SupportsDebugInformation = false;
100 SupportsExceptionHandling = false;
101 DwarfRequiresFrameSection = true;
102 GlobalEHDirective = 0;
103 SupportsWeakOmittedEHFrame = true;
104 DwarfSectionOffsetDirective = 0;
105 DwarfAbbrevSection = ".debug_abbrev";
106 DwarfInfoSection = ".debug_info";
107 DwarfLineSection = ".debug_line";
108 DwarfFrameSection = ".debug_frame";
109 DwarfPubNamesSection = ".debug_pubnames";
110 DwarfPubTypesSection = ".debug_pubtypes";
111 DwarfStrSection = ".debug_str";
112 DwarfLocSection = ".debug_loc";
113 DwarfARangesSection = ".debug_aranges";
114 DwarfRangesSection = ".debug_ranges";
115 DwarfMacInfoSection = ".debug_macinfo";
116 DwarfEHFrameSection = ".eh_frame";
117 DwarfExceptionSection = ".gcc_except_table";
119 TextSection = getUnnamedSection("\t.text", SectionFlags::Code);
120 DataSection = getUnnamedSection("\t.data", SectionFlags::Writeable);
123 TargetAsmInfo::TargetAsmInfo(const TargetMachine &tm)
128 TargetAsmInfo::~TargetAsmInfo() {
131 /// Measure the specified inline asm to determine an approximation of its
133 /// Comments (which run till the next SeparatorChar or newline) do not
134 /// count as an instruction.
135 /// Any other non-whitespace text is considered an instruction, with
136 /// multiple instructions separated by SeparatorChar or newlines.
137 /// Variable-length instructions are not handled here; this function
138 /// may be overloaded in the target code to do that.
139 unsigned TargetAsmInfo::getInlineAsmLength(const char *Str) const {
140 // Count the number of instructions in the asm.
141 bool atInsnStart = true;
143 for (; *Str; ++Str) {
144 if (*Str == '\n' || *Str == SeparatorChar)
146 if (atInsnStart && !isspace(*Str)) {
147 Length += MaxInstLength;
150 if (atInsnStart && strncmp(Str, CommentString, strlen(CommentString))==0)
157 unsigned TargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
159 return dwarf::DW_EH_PE_absptr;
162 static bool isSuitableForBSS(const GlobalVariable *GV) {
163 if (!GV->hasInitializer())
166 // Leave constant zeros in readonly constant sections, so they can be shared
167 Constant *C = GV->getInitializer();
168 return (C->isNullValue() && !GV->isConstant() && !NoZerosInBSS);
172 TargetAsmInfo::SectionKindForGlobal(const GlobalValue *GV) const {
173 // Early exit - functions should be always in text sections.
174 if (isa<Function>(GV))
175 return SectionKind::Text;
177 const GlobalVariable* GVar = dyn_cast<GlobalVariable>(GV);
178 bool isThreadLocal = GVar->isThreadLocal();
179 assert(GVar && "Invalid global value for section selection");
181 if (isSuitableForBSS(GVar)) {
182 // Variable can be easily put to BSS section.
183 return (isThreadLocal ? SectionKind::ThreadBSS : SectionKind::BSS);
184 } else if (GVar->isConstant() && !isThreadLocal) {
185 // Now we know, that varible has initializer and it is constant. We need to
186 // check its initializer to decide, which section to output it into. Also
187 // note, there is no thread-local r/o section.
188 Constant *C = GVar->getInitializer();
189 if (C->ContainsRelocations())
190 return SectionKind::ROData;
192 const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
193 // Check, if initializer is a null-terminated string
194 if (CVA && CVA->isCString())
195 return SectionKind::RODataMergeStr;
197 return SectionKind::RODataMergeConst;
201 // Variable is not constant or thread-local - emit to generic data section.
202 return (isThreadLocal ? SectionKind::ThreadData : SectionKind::Data);
206 TargetAsmInfo::SectionFlagsForGlobal(const GlobalValue *GV,
207 const char* Name) const {
208 unsigned Flags = SectionFlags::None;
210 // Decode flags from global itself.
212 SectionKind::Kind Kind = SectionKindForGlobal(GV);
214 case SectionKind::Text:
215 Flags |= SectionFlags::Code;
217 case SectionKind::ThreadData:
218 case SectionKind::ThreadBSS:
219 Flags |= SectionFlags::TLS;
221 case SectionKind::Data:
222 case SectionKind::BSS:
223 Flags |= SectionFlags::Writeable;
225 case SectionKind::ROData:
226 case SectionKind::RODataMergeStr:
227 case SectionKind::RODataMergeConst:
228 // No additional flags here
230 case SectionKind::SmallData:
231 case SectionKind::SmallBSS:
232 Flags |= SectionFlags::Writeable;
234 case SectionKind::SmallROData:
235 Flags |= SectionFlags::Small;
238 assert(0 && "Unexpected section kind!");
241 if (GV->mayBeOverridden())
242 Flags |= SectionFlags::Linkonce;
245 // Add flags from sections, if any.
247 Flags |= SectionFlags::Named;
249 // Some lame default implementation based on some magic section names.
250 if (strncmp(Name, ".gnu.linkonce.b.", 16) == 0 ||
251 strncmp(Name, ".llvm.linkonce.b.", 17) == 0 ||
252 strncmp(Name, ".gnu.linkonce.sb.", 17) == 0 ||
253 strncmp(Name, ".llvm.linkonce.sb.", 18) == 0)
254 Flags |= SectionFlags::BSS;
255 else if (strcmp(Name, ".tdata") == 0 ||
256 strncmp(Name, ".tdata.", 7) == 0 ||
257 strncmp(Name, ".gnu.linkonce.td.", 17) == 0 ||
258 strncmp(Name, ".llvm.linkonce.td.", 18) == 0)
259 Flags |= SectionFlags::TLS;
260 else if (strcmp(Name, ".tbss") == 0 ||
261 strncmp(Name, ".tbss.", 6) == 0 ||
262 strncmp(Name, ".gnu.linkonce.tb.", 17) == 0 ||
263 strncmp(Name, ".llvm.linkonce.tb.", 18) == 0)
264 Flags |= SectionFlags::BSS | SectionFlags::TLS;
271 TargetAsmInfo::SectionForGlobal(const GlobalValue *GV) const {
273 // Select section name
274 if (GV->hasSection()) {
275 // Honour section already set, if any
276 unsigned Flags = SectionFlagsForGlobal(GV,
277 GV->getSection().c_str());
278 S = getNamedSection(GV->getSection().c_str(), Flags);
280 // Use default section depending on the 'type' of global
281 S = SelectSectionForGlobal(GV);
287 // Lame default implementation. Calculate the section name for global.
289 TargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV) const {
290 SectionKind::Kind Kind = SectionKindForGlobal(GV);
292 if (GV->mayBeOverridden()) {
293 std::string Name = UniqueSectionForGlobal(GV, Kind);
294 unsigned Flags = SectionFlagsForGlobal(GV, Name.c_str());
295 return getNamedSection(Name.c_str(), Flags);
297 if (Kind == SectionKind::Text)
298 return getTextSection();
299 else if (isBSS(Kind) && getBSSSection_())
300 return getBSSSection_();
301 else if (getReadOnlySection() && SectionKind::isReadOnly(Kind))
302 return getReadOnlySection();
305 return getDataSection();
308 // Lame default implementation. Calculate the section name for machine const.
310 TargetAsmInfo::SelectSectionForMachineConst(const Type *Ty) const {
311 // FIXME: Support data.rel stuff someday
312 return getDataSection();
316 TargetAsmInfo::UniqueSectionForGlobal(const GlobalValue* GV,
317 SectionKind::Kind Kind) const {
319 case SectionKind::Text:
320 return ".gnu.linkonce.t." + GV->getName();
321 case SectionKind::Data:
322 return ".gnu.linkonce.d." + GV->getName();
323 case SectionKind::SmallData:
324 return ".gnu.linkonce.s." + GV->getName();
325 case SectionKind::BSS:
326 return ".gnu.linkonce.b." + GV->getName();
327 case SectionKind::SmallBSS:
328 return ".gnu.linkonce.sb." + GV->getName();
329 case SectionKind::ROData:
330 case SectionKind::RODataMergeConst:
331 case SectionKind::RODataMergeStr:
332 return ".gnu.linkonce.r." + GV->getName();
333 case SectionKind::SmallROData:
334 return ".gnu.linkonce.s2." + GV->getName();
335 case SectionKind::ThreadData:
336 return ".gnu.linkonce.td." + GV->getName();
337 case SectionKind::ThreadBSS:
338 return ".gnu.linkonce.tb." + GV->getName();
340 assert(0 && "Unknown section kind");
345 TargetAsmInfo::getNamedSection(const char *Name, unsigned Flags,
346 bool Override) const {
347 Section& S = Sections[Name];
349 // This is newly-created section, set it up properly.
350 if (S.Flags == SectionFlags::Invalid || Override) {
351 S.Flags = Flags | SectionFlags::Named;
359 TargetAsmInfo::getUnnamedSection(const char *Directive, unsigned Flags,
360 bool Override) const {
361 Section& S = Sections[Directive];
363 // This is newly-created section, set it up properly.
364 if (S.Flags == SectionFlags::Invalid || Override) {
365 S.Flags = Flags & ~SectionFlags::Named;
373 TargetAsmInfo::getSectionFlags(unsigned Flags) const {
374 SectionFlags::FlagsStringsMapType::iterator I = FlagsStrings.find(Flags);
376 // We didn't print these flags yet, print and save them to map. This reduces
377 // amount of heap trashing due to std::string construction / concatenation.
378 if (I == FlagsStrings.end())
379 I = FlagsStrings.insert(std::make_pair(Flags,
380 printSectionFlags(Flags))).first;
385 unsigned TargetAsmInfo::getULEB128Size(unsigned Value) {
389 Size += sizeof(int8_t);
394 unsigned TargetAsmInfo::getSLEB128Size(int Value) {
396 int Sign = Value >> (8 * sizeof(Value) - 1);
400 unsigned Byte = Value & 0x7f;
402 IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
403 Size += sizeof(int8_t);