1 //===--- Bitcode/Writer/Writer.cpp - Bitcode Writer -----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Chris Lattner and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Bitcode writer implementation.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Bitcode/ReaderWriter.h"
15 #include "llvm/Bitcode/BitstreamWriter.h"
16 #include "llvm/Bitcode/LLVMBitCodes.h"
17 #include "ValueEnumerator.h"
18 #include "llvm/DerivedTypes.h"
19 #include "llvm/Module.h"
20 #include "llvm/TypeSymbolTable.h"
21 #include "llvm/ValueSymbolTable.h"
22 #include "llvm/Support/MathExtras.h"
25 static const unsigned CurVersion = 0;
27 static void WriteStringRecord(unsigned Code, const std::string &Str,
28 unsigned AbbrevToUse, BitstreamWriter &Stream) {
29 SmallVector<unsigned, 64> Vals;
31 // Code: [strlen, strchar x N]
32 Vals.push_back(Str.size());
33 for (unsigned i = 0, e = Str.size(); i != e; ++i)
34 Vals.push_back(Str[i]);
36 // Emit the finished record.
37 Stream.EmitRecord(Code, Vals, AbbrevToUse);
41 /// WriteTypeTable - Write out the type table for a module.
42 static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
43 const ValueEnumerator::TypeList &TypeList = VE.getTypes();
45 Stream.EnterSubblock(bitc::TYPE_BLOCK_ID, 4 /*count from # abbrevs */);
46 SmallVector<uint64_t, 64> TypeVals;
48 // FIXME: Set up abbrevs now that we know the width of the type fields, etc.
50 // Emit an entry count so the reader can reserve space.
51 TypeVals.push_back(TypeList.size());
52 Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
55 // Loop over all of the types, emitting each in turn.
56 for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
57 const Type *T = TypeList[i].first;
61 switch (T->getTypeID()) {
62 case Type::PackedStructTyID: // FIXME: Delete Type::PackedStructTyID.
63 default: assert(0 && "Unknown type!");
64 case Type::VoidTyID: Code = bitc::TYPE_CODE_VOID; break;
65 case Type::FloatTyID: Code = bitc::TYPE_CODE_FLOAT; break;
66 case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
67 case Type::LabelTyID: Code = bitc::TYPE_CODE_LABEL; break;
68 case Type::OpaqueTyID: Code = bitc::TYPE_CODE_OPAQUE; break;
69 case Type::IntegerTyID:
71 Code = bitc::TYPE_CODE_INTEGER;
72 TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
74 case Type::PointerTyID:
75 // POINTER: [pointee type]
76 Code = bitc::TYPE_CODE_POINTER;
77 TypeVals.push_back(VE.getTypeID(cast<PointerType>(T)->getElementType()));
80 case Type::FunctionTyID: {
81 const FunctionType *FT = cast<FunctionType>(T);
82 // FUNCTION: [isvararg, #pararms, paramty x N]
83 Code = bitc::TYPE_CODE_FUNCTION;
84 TypeVals.push_back(FT->isVarArg());
85 TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
86 // FIXME: PARAM ATTR ID!
87 TypeVals.push_back(FT->getNumParams());
88 for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
89 TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
92 case Type::StructTyID: {
93 const StructType *ST = cast<StructType>(T);
94 // STRUCT: [ispacked, #elts, eltty x N]
95 Code = bitc::TYPE_CODE_STRUCT;
96 TypeVals.push_back(ST->isPacked());
97 TypeVals.push_back(ST->getNumElements());
98 // Output all of the element types...
99 for (StructType::element_iterator I = ST->element_begin(),
100 E = ST->element_end(); I != E; ++I)
101 TypeVals.push_back(VE.getTypeID(*I));
104 case Type::ArrayTyID: {
105 const ArrayType *AT = cast<ArrayType>(T);
106 // ARRAY: [numelts, eltty]
107 Code = bitc::TYPE_CODE_ARRAY;
108 TypeVals.push_back(AT->getNumElements());
109 TypeVals.push_back(VE.getTypeID(AT->getElementType()));
112 case Type::VectorTyID: {
113 const VectorType *VT = cast<VectorType>(T);
114 // VECTOR [numelts, eltty]
115 Code = bitc::TYPE_CODE_VECTOR;
116 TypeVals.push_back(VT->getNumElements());
117 TypeVals.push_back(VE.getTypeID(VT->getElementType()));
122 // Emit the finished record.
123 Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
130 static unsigned getEncodedLinkage(const GlobalValue *GV) {
131 switch (GV->getLinkage()) {
132 default: assert(0 && "Invalid linkage!");
133 case GlobalValue::ExternalLinkage: return 0;
134 case GlobalValue::WeakLinkage: return 1;
135 case GlobalValue::AppendingLinkage: return 2;
136 case GlobalValue::InternalLinkage: return 3;
137 case GlobalValue::LinkOnceLinkage: return 4;
138 case GlobalValue::DLLImportLinkage: return 5;
139 case GlobalValue::DLLExportLinkage: return 6;
140 case GlobalValue::ExternalWeakLinkage: return 7;
144 static unsigned getEncodedVisibility(const GlobalValue *GV) {
145 switch (GV->getVisibility()) {
146 default: assert(0 && "Invalid visibility!");
147 case GlobalValue::DefaultVisibility: return 0;
148 case GlobalValue::HiddenVisibility: return 1;
152 // Emit top-level description of module, including target triple, inline asm,
153 // descriptors for global variables, and function prototype info.
154 static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
155 BitstreamWriter &Stream) {
156 // Emit the list of dependent libraries for the Module.
157 for (Module::lib_iterator I = M->lib_begin(), E = M->lib_end(); I != E; ++I)
158 WriteStringRecord(bitc::MODULE_CODE_DEPLIB, *I, 0/*TODO*/, Stream);
160 // Emit various pieces of data attached to a module.
161 if (!M->getTargetTriple().empty())
162 WriteStringRecord(bitc::MODULE_CODE_TRIPLE, M->getTargetTriple(),
164 if (!M->getDataLayout().empty())
165 WriteStringRecord(bitc::MODULE_CODE_DATALAYOUT, M->getDataLayout(),
167 if (!M->getModuleInlineAsm().empty())
168 WriteStringRecord(bitc::MODULE_CODE_ASM, M->getModuleInlineAsm(),
171 // Emit information about sections, computing how many there are. Also
172 // compute the maximum alignment value.
173 std::map<std::string, unsigned> SectionMap;
174 unsigned MaxAlignment = 0;
175 unsigned MaxGlobalType = 0;
176 for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
178 MaxAlignment = std::max(MaxAlignment, GV->getAlignment());
179 MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV->getType()));
181 if (!GV->hasSection()) continue;
182 // Give section names unique ID's.
183 unsigned &Entry = SectionMap[GV->getSection()];
184 if (Entry != 0) continue;
185 WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV->getSection(),
187 Entry = SectionMap.size();
189 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
190 MaxAlignment = std::max(MaxAlignment, F->getAlignment());
191 if (!F->hasSection()) continue;
192 // Give section names unique ID's.
193 unsigned &Entry = SectionMap[F->getSection()];
194 if (Entry != 0) continue;
195 WriteStringRecord(bitc::MODULE_CODE_SECTIONNAME, F->getSection(),
197 Entry = SectionMap.size();
200 // Emit abbrev for globals, now that we know # sections and max alignment.
201 unsigned SimpleGVarAbbrev = 0;
202 if (!M->global_empty()) {
203 // Add an abbrev for common globals with no visibility or thread localness.
204 BitCodeAbbrev *Abbv = new BitCodeAbbrev();
205 Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
206 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth,
207 Log2_32_Ceil(MaxGlobalType+1)));
208 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 1)); // Constant.
209 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Initializer.
210 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth, 3)); // Linkage.
211 if (MaxAlignment == 0) // Alignment.
212 Abbv->Add(BitCodeAbbrevOp(0));
214 unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
215 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth,
216 Log2_32_Ceil(MaxEncAlignment+1)));
218 if (SectionMap.empty()) // Section.
219 Abbv->Add(BitCodeAbbrevOp(0));
221 Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::FixedWidth,
222 Log2_32_Ceil(SectionMap.size())));
223 // Don't bother emitting vis + thread local.
224 SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
227 // Emit the global variable information.
228 SmallVector<unsigned, 64> Vals;
229 for (Module::const_global_iterator GV = M->global_begin(),E = M->global_end();
231 unsigned AbbrevToUse = 0;
233 // GLOBALVAR: [type, isconst, initid,
234 // linkage, alignment, section, visibility, threadlocal]
235 Vals.push_back(VE.getTypeID(GV->getType()));
236 Vals.push_back(GV->isConstant());
237 Vals.push_back(GV->isDeclaration() ? 0 :
238 (VE.getValueID(GV->getInitializer()) + 1));
239 Vals.push_back(getEncodedLinkage(GV));
240 Vals.push_back(Log2_32(GV->getAlignment())+1);
241 Vals.push_back(GV->hasSection() ? SectionMap[GV->getSection()] : 0);
242 if (GV->isThreadLocal() ||
243 GV->getVisibility() != GlobalValue::DefaultVisibility) {
244 Vals.push_back(getEncodedVisibility(GV));
245 Vals.push_back(GV->isThreadLocal());
247 AbbrevToUse = SimpleGVarAbbrev;
250 Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
254 // Emit the function proto information.
255 for (Module::const_iterator F = M->begin(), E = M->end(); F != E; ++F) {
256 // FUNCTION: [type, callingconv, isproto, linkage, alignment, section,
258 Vals.push_back(VE.getTypeID(F->getType()));
259 Vals.push_back(F->getCallingConv());
260 Vals.push_back(F->isDeclaration());
261 Vals.push_back(getEncodedLinkage(F));
262 Vals.push_back(Log2_32(F->getAlignment())+1);
263 Vals.push_back(F->hasSection() ? SectionMap[F->getSection()] : 0);
264 Vals.push_back(getEncodedVisibility(F));
266 unsigned AbbrevToUse = 0;
267 Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
273 /// WriteTypeSymbolTable - Emit a block for the specified type symtab.
274 static void WriteTypeSymbolTable(const TypeSymbolTable &TST,
275 const ValueEnumerator &VE,
276 BitstreamWriter &Stream) {
277 if (TST.empty()) return;
279 Stream.EnterSubblock(bitc::TYPE_SYMTAB_BLOCK_ID, 3);
281 // FIXME: Set up the abbrev, we know how many types there are!
282 // FIXME: We know if the type names can use 7-bit ascii.
284 SmallVector<unsigned, 64> NameVals;
286 for (TypeSymbolTable::const_iterator TI = TST.begin(), TE = TST.end();
288 unsigned AbbrevToUse = 0;
290 // TST_ENTRY: [typeid, namelen, namechar x N]
291 NameVals.push_back(VE.getTypeID(TI->second));
293 const std::string &Str = TI->first;
294 NameVals.push_back(Str.size());
295 for (unsigned i = 0, e = Str.size(); i != e; ++i)
296 NameVals.push_back(Str[i]);
298 // Emit the finished record.
299 Stream.EmitRecord(bitc::TST_ENTRY_CODE, NameVals, AbbrevToUse);
306 // Emit names for globals/functions etc.
307 static void WriteValueSymbolTable(const ValueSymbolTable &VST,
308 const ValueEnumerator &VE,
309 BitstreamWriter &Stream) {
310 if (VST.empty()) return;
311 Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 3);
313 // FIXME: Set up the abbrev, we know how many values there are!
314 // FIXME: We know if the type names can use 7-bit ascii.
315 SmallVector<unsigned, 64> NameVals;
317 for (ValueSymbolTable::const_iterator SI = VST.begin(), SE = VST.end();
319 unsigned AbbrevToUse = 0;
321 // VST_ENTRY: [valueid, namelen, namechar x N]
322 NameVals.push_back(VE.getValueID(SI->getValue()));
324 NameVals.push_back(SI->getKeyLength());
325 for (const char *P = SI->getKeyData(),
326 *E = SI->getKeyData()+SI->getKeyLength(); P != E; ++P)
327 NameVals.push_back((unsigned char)*P);
329 // Emit the finished record.
330 Stream.EmitRecord(bitc::VST_ENTRY_CODE, NameVals, AbbrevToUse);
338 /// WriteModule - Emit the specified module to the bitstream.
339 static void WriteModule(const Module *M, BitstreamWriter &Stream) {
340 Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
342 // Emit the version number if it is non-zero.
344 SmallVector<unsigned, 1> VersionVals;
345 VersionVals.push_back(CurVersion);
346 Stream.EmitRecord(bitc::MODULE_CODE_VERSION, VersionVals);
349 // Analyze the module, enumerating globals, functions, etc.
350 ValueEnumerator VE(M);
352 // Emit information describing all of the types in the module.
353 WriteTypeTable(VE, Stream);
355 // FIXME: Emit constants.
357 // Emit top-level description of module, including target triple, inline asm,
358 // descriptors for global variables, and function prototype info.
359 WriteModuleInfo(M, VE, Stream);
361 // Emit the type symbol table information.
362 WriteTypeSymbolTable(M->getTypeSymbolTable(), VE, Stream);
364 // Emit names for globals/functions etc.
365 WriteValueSymbolTable(M->getValueSymbolTable(), VE, Stream);
370 /// WriteBitcodeToFile - Write the specified module to the specified output
372 void llvm::WriteBitcodeToFile(const Module *M, std::ostream &Out) {
373 std::vector<unsigned char> Buffer;
374 BitstreamWriter Stream(Buffer);
376 Buffer.reserve(256*1024);
378 // Emit the file header.
379 Stream.Emit((unsigned)'B', 8);
380 Stream.Emit((unsigned)'C', 8);
387 WriteModule(M, Stream);
389 // Write the generated bitstream to "Out".
390 Out.write((char*)&Buffer.front(), Buffer.size());