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Mikhail Glushenkov59a5afa2009-03-03 10:04:23 +00001//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===//
Misha Brukman10468d82005-04-21 22:55:34 +00002//
Reid Spencer361e5132004-11-12 20:37:43 +00003// The LLVM Compiler Infrastructure
4//
Chris Lattnerf3ebc3f2007-12-29 20:36:04 +00005// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
Misha Brukman10468d82005-04-21 22:55:34 +00007//
Reid Spencer361e5132004-11-12 20:37:43 +00008//===----------------------------------------------------------------------===//
9//
10// This file implements the LLVM module linker.
11//
Reid Spencer361e5132004-11-12 20:37:43 +000012//===----------------------------------------------------------------------===//
13
Chandler Carruth6cc07df2014-03-06 03:42:23 +000014#include "llvm/Linker/Linker.h"
Chandler Carruthed0881b2012-12-03 16:50:05 +000015#include "llvm-c/Linker.h"
Rafael Espindola31ad4682014-12-03 22:36:37 +000016#include "llvm/ADT/Hashing.h"
Rafael Espindola23f8d642012-01-05 23:02:01 +000017#include "llvm/ADT/Optional.h"
Bill Wendling66f02412012-02-11 11:38:06 +000018#include "llvm/ADT/SetVector.h"
Eli Bendersky0f7fd362013-03-19 15:26:24 +000019#include "llvm/ADT/SmallString.h"
Rafael Espindola31ad4682014-12-03 22:36:37 +000020#include "llvm/ADT/Statistic.h"
Akira Hatanakac43df512015-02-13 00:40:41 +000021#include "llvm/ADT/Triple.h"
Chandler Carruth9fb823b2013-01-02 11:36:10 +000022#include "llvm/IR/Constants.h"
Duncan P. N. Exon Smithfda0cee2014-12-18 01:05:33 +000023#include "llvm/IR/DebugInfo.h"
Rafael Espindolad12b4a32014-10-25 04:06:10 +000024#include "llvm/IR/DiagnosticInfo.h"
25#include "llvm/IR/DiagnosticPrinter.h"
26#include "llvm/IR/LLVMContext.h"
Chandler Carruth9fb823b2013-01-02 11:36:10 +000027#include "llvm/IR/Module.h"
Chandler Carruthdcb603f2013-01-07 15:43:51 +000028#include "llvm/IR/TypeFinder.h"
Eli Benderskye17f3702014-02-06 18:01:56 +000029#include "llvm/Support/CommandLine.h"
Bill Wendlingb6af2f32012-03-22 20:28:27 +000030#include "llvm/Support/Debug.h"
Bill Wendlingb6af2f32012-03-22 20:28:27 +000031#include "llvm/Support/raw_ostream.h"
Tanya Lattnercbb91402011-10-11 00:24:54 +000032#include "llvm/Transforms/Utils/Cloning.h"
Will Dietz981af002013-10-12 00:55:57 +000033#include <cctype>
David Majnemer82d6ff62014-06-27 18:38:12 +000034#include <tuple>
Reid Spencer361e5132004-11-12 20:37:43 +000035using namespace llvm;
36
Eli Benderskye17f3702014-02-06 18:01:56 +000037
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000038//===----------------------------------------------------------------------===//
39// TypeMap implementation.
40//===----------------------------------------------------------------------===//
Reid Spencer361e5132004-11-12 20:37:43 +000041
Chris Lattnereee6f992008-06-16 21:00:18 +000042namespace {
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000043class TypeMapTy : public ValueMapTypeRemapper {
Rafael Espindola18c89412014-10-27 02:35:46 +000044 /// This is a mapping from a source type to a destination type to use.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000045 DenseMap<Type*, Type*> MappedTypes;
Mikhail Glushenkov766d4892009-03-03 07:22:23 +000046
Rafael Espindola18c89412014-10-27 02:35:46 +000047 /// When checking to see if two subgraphs are isomorphic, we speculatively
48 /// add types to MappedTypes, but keep track of them here in case we need to
49 /// roll back.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000050 SmallVector<Type*, 16> SpeculativeTypes;
Rafael Espindolaed6dc372014-05-09 14:39:25 +000051
Rafael Espindolaa96f2352014-11-28 16:41:24 +000052 SmallVector<StructType*, 16> SpeculativeDstOpaqueTypes;
53
Rafael Espindola18c89412014-10-27 02:35:46 +000054 /// This is a list of non-opaque structs in the source module that are mapped
55 /// to an opaque struct in the destination module.
Chris Lattner5e3bd972011-12-20 00:03:52 +000056 SmallVector<StructType*, 16> SrcDefinitionsToResolve;
Rafael Espindolaed6dc372014-05-09 14:39:25 +000057
Rafael Espindola18c89412014-10-27 02:35:46 +000058 /// This is the set of opaque types in the destination modules who are
59 /// getting a body from the source module.
Chris Lattner5e3bd972011-12-20 00:03:52 +000060 SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
Bill Wendling8c2cc412012-03-22 20:30:41 +000061
Chris Lattner56cdea62008-06-16 23:06:51 +000062public:
Rafael Espindola31ad4682014-12-03 22:36:37 +000063 TypeMapTy(Linker::IdentifiedStructTypeSet &DstStructTypesSet)
64 : DstStructTypesSet(DstStructTypesSet) {}
Rafael Espindolaaa9918a2013-05-04 05:05:18 +000065
Rafael Espindola31ad4682014-12-03 22:36:37 +000066 Linker::IdentifiedStructTypeSet &DstStructTypesSet;
Rafael Espindola18c89412014-10-27 02:35:46 +000067 /// Indicate that the specified type in the destination module is conceptually
68 /// equivalent to the specified type in the source module.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000069 void addTypeMapping(Type *DstTy, Type *SrcTy);
70
Rafael Espindolad2a13a22014-11-25 04:28:31 +000071 /// Produce a body for an opaque type in the dest module from a type
72 /// definition in the source module.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000073 void linkDefinedTypeBodies();
Rafael Espindolaed6dc372014-05-09 14:39:25 +000074
Rafael Espindola18c89412014-10-27 02:35:46 +000075 /// Return the mapped type to use for the specified input type from the
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000076 /// source module.
77 Type *get(Type *SrcTy);
Rafael Espindola31ad4682014-12-03 22:36:37 +000078 Type *get(Type *SrcTy, SmallPtrSet<StructType *, 8> &Visited);
79
80 void finishType(StructType *DTy, StructType *STy, ArrayRef<Type *> ETypes);
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000081
Rafael Espindola290e2cc2014-11-25 14:35:53 +000082 FunctionType *get(FunctionType *T) {
83 return cast<FunctionType>(get((Type *)T));
84 }
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000085
Rafael Espindola18c89412014-10-27 02:35:46 +000086 /// Dump out the type map for debugging purposes.
Bill Wendlingb6af2f32012-03-22 20:28:27 +000087 void dump() const {
Rafael Espindola8f144712014-11-25 06:16:27 +000088 for (auto &Pair : MappedTypes) {
Bill Wendlingb6af2f32012-03-22 20:28:27 +000089 dbgs() << "TypeMap: ";
Rafael Espindola8f144712014-11-25 06:16:27 +000090 Pair.first->print(dbgs());
Bill Wendlingb6af2f32012-03-22 20:28:27 +000091 dbgs() << " => ";
Rafael Espindola8f144712014-11-25 06:16:27 +000092 Pair.second->print(dbgs());
Bill Wendlingb6af2f32012-03-22 20:28:27 +000093 dbgs() << '\n';
94 }
95 }
Bill Wendlingb6af2f32012-03-22 20:28:27 +000096
Chris Lattnerb1ed91f2011-07-09 17:41:24 +000097private:
Rafael Espindola290e2cc2014-11-25 14:35:53 +000098 Type *remapType(Type *SrcTy) override { return get(SrcTy); }
Rafael Espindolaed6dc372014-05-09 14:39:25 +000099
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000100 bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
Chris Lattnereee6f992008-06-16 21:00:18 +0000101};
Alexander Kornienkof00654e2015-06-23 09:49:53 +0000102}
Chris Lattnereee6f992008-06-16 21:00:18 +0000103
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000104void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
Rafael Espindola3d097412014-11-28 16:26:14 +0000105 assert(SpeculativeTypes.empty());
Rafael Espindolaa96f2352014-11-28 16:41:24 +0000106 assert(SpeculativeDstOpaqueTypes.empty());
Rafael Espindola3d097412014-11-28 16:26:14 +0000107
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000108 // Check to see if these types are recursively isomorphic and establish a
109 // mapping between them if so.
Duncan P. N. Exon Smithc586eaa2014-11-27 17:01:10 +0000110 if (!areTypesIsomorphic(DstTy, SrcTy)) {
111 // Oops, they aren't isomorphic. Just discard this request by rolling out
112 // any speculative mappings we've established.
Rafael Espindola3d097412014-11-28 16:26:14 +0000113 for (Type *Ty : SpeculativeTypes)
114 MappedTypes.erase(Ty);
Rafael Espindolaa96f2352014-11-28 16:41:24 +0000115
116 SrcDefinitionsToResolve.resize(SrcDefinitionsToResolve.size() -
117 SpeculativeDstOpaqueTypes.size());
118 for (StructType *Ty : SpeculativeDstOpaqueTypes)
119 DstResolvedOpaqueTypes.erase(Ty);
Rafael Espindola04a74af2014-12-01 04:15:59 +0000120 } else {
121 for (Type *Ty : SpeculativeTypes)
122 if (auto *STy = dyn_cast<StructType>(Ty))
123 if (STy->hasName())
124 STy->setName("");
Bill Wendlingd48b7782012-02-28 04:01:21 +0000125 }
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000126 SpeculativeTypes.clear();
Rafael Espindolaa96f2352014-11-28 16:41:24 +0000127 SpeculativeDstOpaqueTypes.clear();
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000128}
Chris Lattnereee6f992008-06-16 21:00:18 +0000129
Rafael Espindola18c89412014-10-27 02:35:46 +0000130/// Recursively walk this pair of types, returning true if they are isomorphic,
131/// false if they are not.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000132bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
133 // Two types with differing kinds are clearly not isomorphic.
Rafael Espindola290e2cc2014-11-25 14:35:53 +0000134 if (DstTy->getTypeID() != SrcTy->getTypeID())
135 return false;
Misha Brukman10468d82005-04-21 22:55:34 +0000136
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000137 // If we have an entry in the MappedTypes table, then we have our answer.
138 Type *&Entry = MappedTypes[SrcTy];
139 if (Entry)
140 return Entry == DstTy;
Misha Brukman10468d82005-04-21 22:55:34 +0000141
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000142 // Two identical types are clearly isomorphic. Remember this
143 // non-speculatively.
144 if (DstTy == SrcTy) {
145 Entry = DstTy;
Chris Lattnerfe677e92008-06-16 20:03:01 +0000146 return true;
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000147 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000148
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000149 // Okay, we have two types with identical kinds that we haven't seen before.
Mikhail Glushenkov766d4892009-03-03 07:22:23 +0000150
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000151 // If this is an opaque struct type, special case it.
152 if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
153 // Mapping an opaque type to any struct, just keep the dest struct.
154 if (SSTy->isOpaque()) {
155 Entry = DstTy;
156 SpeculativeTypes.push_back(SrcTy);
Reid Spencer361e5132004-11-12 20:37:43 +0000157 return true;
Chris Lattner9be15892008-06-16 21:17:12 +0000158 }
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000159
Chris Lattner5e3bd972011-12-20 00:03:52 +0000160 // Mapping a non-opaque source type to an opaque dest. If this is the first
161 // type that we're mapping onto this destination type then we succeed. Keep
Rafael Espindolaa96f2352014-11-28 16:41:24 +0000162 // the dest, but fill it in later. If this is the second (different) type
163 // that we're trying to map onto the same opaque type then we fail.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000164 if (cast<StructType>(DstTy)->isOpaque()) {
Chris Lattner5e3bd972011-12-20 00:03:52 +0000165 // We can only map one source type onto the opaque destination type.
David Blaikie70573dc2014-11-19 07:49:26 +0000166 if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)).second)
Chris Lattner5e3bd972011-12-20 00:03:52 +0000167 return false;
168 SrcDefinitionsToResolve.push_back(SSTy);
Rafael Espindolaa96f2352014-11-28 16:41:24 +0000169 SpeculativeTypes.push_back(SrcTy);
170 SpeculativeDstOpaqueTypes.push_back(cast<StructType>(DstTy));
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000171 Entry = DstTy;
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000172 return true;
173 }
174 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000175
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000176 // If the number of subtypes disagree between the two types, then we fail.
177 if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
Reid Spencer361e5132004-11-12 20:37:43 +0000178 return false;
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000179
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000180 // Fail if any of the extra properties (e.g. array size) of the type disagree.
181 if (isa<IntegerType>(DstTy))
182 return false; // bitwidth disagrees.
183 if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
184 if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
185 return false;
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000186
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000187 } else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
188 if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
189 return false;
190 } else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
191 StructType *SSTy = cast<StructType>(SrcTy);
Chris Lattner44f7ab42011-08-12 18:07:26 +0000192 if (DSTy->isLiteral() != SSTy->isLiteral() ||
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000193 DSTy->isPacked() != SSTy->isPacked())
194 return false;
195 } else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
196 if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
197 return false;
198 } else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
Joey Gouly5fad3e92013-01-10 10:49:36 +0000199 if (DVTy->getNumElements() != cast<VectorType>(SrcTy)->getNumElements())
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000200 return false;
Reid Spencer361e5132004-11-12 20:37:43 +0000201 }
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000202
203 // Otherwise, we speculate that these two types will line up and recursively
204 // check the subelements.
205 Entry = DstTy;
206 SpeculativeTypes.push_back(SrcTy);
207
Rafael Espindola290e2cc2014-11-25 14:35:53 +0000208 for (unsigned I = 0, E = SrcTy->getNumContainedTypes(); I != E; ++I)
209 if (!areTypesIsomorphic(DstTy->getContainedType(I),
210 SrcTy->getContainedType(I)))
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000211 return false;
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000212
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000213 // If everything seems to have lined up, then everything is great.
214 return true;
215}
216
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000217void TypeMapTy::linkDefinedTypeBodies() {
218 SmallVector<Type*, 16> Elements;
Rafael Espindolac81c3f52014-11-25 15:33:40 +0000219 for (StructType *SrcSTy : SrcDefinitionsToResolve) {
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000220 StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
Rafael Espindolac81c3f52014-11-25 15:33:40 +0000221 assert(DstSTy->isOpaque());
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000222
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000223 // Map the body of the source type over to a new body for the dest type.
224 Elements.resize(SrcSTy->getNumElements());
Rafael Espindola290e2cc2014-11-25 14:35:53 +0000225 for (unsigned I = 0, E = Elements.size(); I != E; ++I)
Rafael Espindolac81c3f52014-11-25 15:33:40 +0000226 Elements[I] = get(SrcSTy->getElementType(I));
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000227
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000228 DstSTy->setBody(Elements, SrcSTy->isPacked());
Rafael Espindolaa5b9e1c2015-03-06 00:50:21 +0000229 DstStructTypesSet.switchToNonOpaque(DstSTy);
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000230 }
Rafael Espindolac81c3f52014-11-25 15:33:40 +0000231 SrcDefinitionsToResolve.clear();
Chris Lattner5e3bd972011-12-20 00:03:52 +0000232 DstResolvedOpaqueTypes.clear();
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000233}
234
Rafael Espindola31ad4682014-12-03 22:36:37 +0000235void TypeMapTy::finishType(StructType *DTy, StructType *STy,
236 ArrayRef<Type *> ETypes) {
237 DTy->setBody(ETypes, STy->isPacked());
Rafael Espindolac81c3f52014-11-25 15:33:40 +0000238
239 // Steal STy's name.
240 if (STy->hasName()) {
241 SmallString<16> TmpName = STy->getName();
242 STy->setName("");
243 DTy->setName(TmpName);
244 }
245
Rafael Espindola31ad4682014-12-03 22:36:37 +0000246 DstStructTypesSet.addNonOpaque(DTy);
247}
248
249Type *TypeMapTy::get(Type *Ty) {
250 SmallPtrSet<StructType *, 8> Visited;
251 return get(Ty, Visited);
252}
253
254Type *TypeMapTy::get(Type *Ty, SmallPtrSet<StructType *, 8> &Visited) {
255 // If we already have an entry for this type, return it.
256 Type **Entry = &MappedTypes[Ty];
257 if (*Entry)
258 return *Entry;
259
260 // These are types that LLVM itself will unique.
261 bool IsUniqued = !isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral();
262
263#ifndef NDEBUG
264 if (!IsUniqued) {
265 for (auto &Pair : MappedTypes) {
266 assert(!(Pair.first != Ty && Pair.second == Ty) &&
267 "mapping to a source type");
268 }
269 }
270#endif
271
272 if (!IsUniqued && !Visited.insert(cast<StructType>(Ty)).second) {
273 StructType *DTy = StructType::create(Ty->getContext());
274 return *Entry = DTy;
275 }
276
277 // If this is not a recursive type, then just map all of the elements and
278 // then rebuild the type from inside out.
279 SmallVector<Type *, 4> ElementTypes;
280
281 // If there are no element types to map, then the type is itself. This is
282 // true for the anonymous {} struct, things like 'float', integers, etc.
283 if (Ty->getNumContainedTypes() == 0 && IsUniqued)
284 return *Entry = Ty;
285
286 // Remap all of the elements, keeping track of whether any of them change.
287 bool AnyChange = false;
288 ElementTypes.resize(Ty->getNumContainedTypes());
289 for (unsigned I = 0, E = Ty->getNumContainedTypes(); I != E; ++I) {
290 ElementTypes[I] = get(Ty->getContainedType(I), Visited);
291 AnyChange |= ElementTypes[I] != Ty->getContainedType(I);
292 }
293
294 // If we found our type while recursively processing stuff, just use it.
295 Entry = &MappedTypes[Ty];
296 if (*Entry) {
297 if (auto *DTy = dyn_cast<StructType>(*Entry)) {
298 if (DTy->isOpaque()) {
299 auto *STy = cast<StructType>(Ty);
300 finishType(DTy, STy, ElementTypes);
301 }
302 }
303 return *Entry;
304 }
305
306 // If all of the element types mapped directly over and the type is not
307 // a nomed struct, then the type is usable as-is.
308 if (!AnyChange && IsUniqued)
309 return *Entry = Ty;
310
311 // Otherwise, rebuild a modified type.
312 switch (Ty->getTypeID()) {
313 default:
314 llvm_unreachable("unknown derived type to remap");
315 case Type::ArrayTyID:
316 return *Entry = ArrayType::get(ElementTypes[0],
317 cast<ArrayType>(Ty)->getNumElements());
318 case Type::VectorTyID:
319 return *Entry = VectorType::get(ElementTypes[0],
320 cast<VectorType>(Ty)->getNumElements());
321 case Type::PointerTyID:
322 return *Entry = PointerType::get(ElementTypes[0],
323 cast<PointerType>(Ty)->getAddressSpace());
324 case Type::FunctionTyID:
325 return *Entry = FunctionType::get(ElementTypes[0],
326 makeArrayRef(ElementTypes).slice(1),
327 cast<FunctionType>(Ty)->isVarArg());
328 case Type::StructTyID: {
329 auto *STy = cast<StructType>(Ty);
330 bool IsPacked = STy->isPacked();
331 if (IsUniqued)
332 return *Entry = StructType::get(Ty->getContext(), ElementTypes, IsPacked);
333
334 // If the type is opaque, we can just use it directly.
335 if (STy->isOpaque()) {
336 DstStructTypesSet.addOpaque(STy);
337 return *Entry = Ty;
338 }
339
340 if (StructType *OldT =
341 DstStructTypesSet.findNonOpaque(ElementTypes, IsPacked)) {
342 STy->setName("");
343 return *Entry = OldT;
344 }
345
346 if (!AnyChange) {
347 DstStructTypesSet.addNonOpaque(STy);
348 return *Entry = Ty;
349 }
350
351 StructType *DTy = StructType::create(Ty->getContext());
352 finishType(DTy, STy, ElementTypes);
353 return *Entry = DTy;
354 }
355 }
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000356}
357
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000358//===----------------------------------------------------------------------===//
359// ModuleLinker implementation.
360//===----------------------------------------------------------------------===//
361
362namespace {
Rafael Espindolac84f6082014-11-25 06:11:24 +0000363class ModuleLinker;
James Molloyf6f121e2013-05-28 15:17:05 +0000364
Rafael Espindolac84f6082014-11-25 06:11:24 +0000365/// Creates prototypes for functions that are lazily linked on the fly. This
366/// speeds up linking for modules with many/ lazily linked functions of which
367/// few get used.
David Blaikie437aafd2015-10-19 22:15:55 +0000368class ValueMaterializerTy final : public ValueMaterializer {
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000369 ModuleLinker *ModLinker;
James Molloyf6f121e2013-05-28 15:17:05 +0000370
Rafael Espindolac84f6082014-11-25 06:11:24 +0000371public:
Rafael Espindola19b52382015-11-27 20:28:19 +0000372 ValueMaterializerTy(ModuleLinker *ModLinker) : ModLinker(ModLinker) {}
Rafael Espindolac84f6082014-11-25 06:11:24 +0000373
Rafael Espindola19b52382015-11-27 20:28:19 +0000374 Value *materializeDeclFor(Value *V) override;
375 void materializeInitFor(GlobalValue *New, GlobalValue *Old) override;
Rafael Espindolac84f6082014-11-25 06:11:24 +0000376};
377
378class LinkDiagnosticInfo : public DiagnosticInfo {
379 const Twine &Msg;
380
381public:
382 LinkDiagnosticInfo(DiagnosticSeverity Severity, const Twine &Msg);
383 void print(DiagnosticPrinter &DP) const override;
384};
385LinkDiagnosticInfo::LinkDiagnosticInfo(DiagnosticSeverity Severity,
386 const Twine &Msg)
387 : DiagnosticInfo(DK_Linker, Severity), Msg(Msg) {}
388void LinkDiagnosticInfo::print(DiagnosticPrinter &DP) const { DP << Msg; }
389
390/// This is an implementation class for the LinkModules function, which is the
391/// entrypoint for this file.
392class ModuleLinker {
393 Module *DstM, *SrcM;
394
395 TypeMapTy TypeMap;
396 ValueMaterializerTy ValMaterializer;
397
398 /// Mapping of values from what they used to be in Src, to what they are now
399 /// in DstM. ValueToValueMapTy is a ValueMap, which involves some overhead
400 /// due to the use of Value handles which the Linker doesn't actually need,
401 /// but this allows us to reuse the ValueMapper code.
402 ValueToValueMapTy ValueMap;
403
Rafael Espindolac84f6082014-11-25 06:11:24 +0000404 // Set of items not to link in from source.
Rafael Espindolac98b20b2015-11-30 18:54:24 +0000405 SmallPtrSet<const GlobalValue *, 16> DoNotLinkFromSource;
Rafael Espindolad12b4a32014-10-25 04:06:10 +0000406
Rafael Espindolad0b23be2015-01-10 00:07:30 +0000407 DiagnosticHandlerFunction DiagnosticHandler;
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000408
Duncan P. N. Exon Smithe8681232015-04-22 04:11:00 +0000409 /// For symbol clashes, prefer those from Src.
Artem Belevich020d4fb2015-09-01 17:55:55 +0000410 unsigned Flags;
Duncan P. N. Exon Smithe8681232015-04-22 04:11:00 +0000411
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000412 /// Function index passed into ModuleLinker for using in function
413 /// importing/exporting handling.
Mehdi Amini8220e8a2015-11-23 01:59:16 +0000414 const FunctionInfoIndex *ImportIndex;
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000415
416 /// Function to import from source module, all other functions are
417 /// imported as declarations instead of definitions.
418 Function *ImportFunction;
419
420 /// Set to true if the given FunctionInfoIndex contains any functions
421 /// from this source module, in which case we must conservatively assume
422 /// that any of its functions may be imported into another module
423 /// as part of a different backend compilation process.
424 bool HasExportedFunctions;
425
Teresa Johnson10632932015-11-06 17:50:53 +0000426 /// Set to true when all global value body linking is complete (including
427 /// lazy linking). Used to prevent metadata linking from creating new
428 /// references.
429 bool DoneLinkingBodies;
430
Rafael Espindolabaa3bf82015-12-01 15:19:48 +0000431 bool HasError = false;
432
Rafael Espindolac84f6082014-11-25 06:11:24 +0000433public:
Rafael Espindola31ad4682014-12-03 22:36:37 +0000434 ModuleLinker(Module *dstM, Linker::IdentifiedStructTypeSet &Set, Module *srcM,
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000435 DiagnosticHandlerFunction DiagnosticHandler, unsigned Flags,
Mehdi Amini8220e8a2015-11-23 01:59:16 +0000436 const FunctionInfoIndex *Index = nullptr,
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000437 Function *FuncToImport = nullptr)
Rafael Espindola19b52382015-11-27 20:28:19 +0000438 : DstM(dstM), SrcM(srcM), TypeMap(Set), ValMaterializer(this),
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000439 DiagnosticHandler(DiagnosticHandler), Flags(Flags), ImportIndex(Index),
Teresa Johnson10632932015-11-06 17:50:53 +0000440 ImportFunction(FuncToImport), HasExportedFunctions(false),
441 DoneLinkingBodies(false) {
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000442 assert((ImportIndex || !ImportFunction) &&
443 "Expect a FunctionInfoIndex when importing");
444 // If we have a FunctionInfoIndex but no function to import,
445 // then this is the primary module being compiled in a ThinLTO
446 // backend compilation, and we need to see if it has functions that
447 // may be exported to another backend compilation.
448 if (ImportIndex && !ImportFunction)
449 HasExportedFunctions = ImportIndex->hasExportedFunctions(SrcM);
450 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000451
Rafael Espindolac84f6082014-11-25 06:11:24 +0000452 bool run();
Rafael Espindola19b52382015-11-27 20:28:19 +0000453 Value *materializeDeclFor(Value *V);
454 void materializeInitFor(GlobalValue *New, GlobalValue *Old);
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000455
Rafael Espindola19b52382015-11-27 20:28:19 +0000456private:
Artem Belevich020d4fb2015-09-01 17:55:55 +0000457 bool shouldOverrideFromSrc() { return Flags & Linker::OverrideFromSrc; }
458 bool shouldLinkOnlyNeeded() { return Flags & Linker::LinkOnlyNeeded; }
459 bool shouldInternalizeLinkedSymbols() {
460 return Flags & Linker::InternalizeLinkedSymbols;
461 }
462
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000463 /// Handles cloning of a global values from the source module into
464 /// the destination module, including setting the attributes and visibility.
465 GlobalValue *copyGlobalValueProto(TypeMapTy &TypeMap, const GlobalValue *SGV,
466 const GlobalValue *DGV = nullptr);
467
468 /// Check if we should promote the given local value to global scope.
469 bool doPromoteLocalToGlobal(const GlobalValue *SGV);
470
Teresa Johnson10632932015-11-06 17:50:53 +0000471 /// Check if all global value body linking is complete.
472 bool doneLinkingBodies() { return DoneLinkingBodies; }
473
Rafael Espindolac84f6082014-11-25 06:11:24 +0000474 bool shouldLinkFromSource(bool &LinkFromSrc, const GlobalValue &Dest,
475 const GlobalValue &Src);
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000476
Rafael Espindolac84f6082014-11-25 06:11:24 +0000477 /// Helper method for setting a message and returning an error code.
478 bool emitError(const Twine &Message) {
479 DiagnosticHandler(LinkDiagnosticInfo(DS_Error, Message));
Rafael Espindolabaa3bf82015-12-01 15:19:48 +0000480 HasError = true;
Rafael Espindolac84f6082014-11-25 06:11:24 +0000481 return true;
482 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000483
Rafael Espindolac84f6082014-11-25 06:11:24 +0000484 void emitWarning(const Twine &Message) {
485 DiagnosticHandler(LinkDiagnosticInfo(DS_Warning, Message));
486 }
Eli Bendersky7da92ed2014-02-20 22:19:24 +0000487
Rafael Espindolac84f6082014-11-25 06:11:24 +0000488 bool getComdatLeader(Module *M, StringRef ComdatName,
489 const GlobalVariable *&GVar);
490 bool computeResultingSelectionKind(StringRef ComdatName,
491 Comdat::SelectionKind Src,
492 Comdat::SelectionKind Dst,
493 Comdat::SelectionKind &Result,
494 bool &LinkFromSrc);
495 std::map<const Comdat *, std::pair<Comdat::SelectionKind, bool>>
496 ComdatsChosen;
497 bool getComdatResult(const Comdat *SrcC, Comdat::SelectionKind &SK,
498 bool &LinkFromSrc);
Teresa Johnson2d5fb8c2015-11-10 21:09:06 +0000499 // Keep track of the global value members of each comdat in source.
500 DenseMap<const Comdat *, std::vector<GlobalValue *>> ComdatMembers;
Rafael Espindola4160f5d2014-10-27 23:02:10 +0000501
Rafael Espindolac84f6082014-11-25 06:11:24 +0000502 /// Given a global in the source module, return the global in the
503 /// destination module that is being linked to, if any.
504 GlobalValue *getLinkedToGlobal(const GlobalValue *SrcGV) {
505 // If the source has no name it can't link. If it has local linkage,
506 // there is no name match-up going on.
Teresa Johnsonb098f0c2015-11-24 19:46:58 +0000507 if (!SrcGV->hasName() || GlobalValue::isLocalLinkage(getLinkage(SrcGV)))
Rafael Espindolac84f6082014-11-25 06:11:24 +0000508 return nullptr;
Eli Bendersky7da92ed2014-02-20 22:19:24 +0000509
Rafael Espindolac84f6082014-11-25 06:11:24 +0000510 // Otherwise see if we have a match in the destination module's symtab.
Teresa Johnsonb098f0c2015-11-24 19:46:58 +0000511 GlobalValue *DGV = DstM->getNamedValue(getName(SrcGV));
Rafael Espindolac84f6082014-11-25 06:11:24 +0000512 if (!DGV)
513 return nullptr;
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000514
Rafael Espindolac84f6082014-11-25 06:11:24 +0000515 // If we found a global with the same name in the dest module, but it has
516 // internal linkage, we are really not doing any linkage here.
517 if (DGV->hasLocalLinkage())
518 return nullptr;
Rafael Espindoladbb0bd12014-09-09 15:21:00 +0000519
Rafael Espindolac84f6082014-11-25 06:11:24 +0000520 // Otherwise, we do in fact link to the destination global.
521 return DGV;
522 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000523
Rafael Espindolac84f6082014-11-25 06:11:24 +0000524 void computeTypeMapping();
Rafael Espindolad12b4a32014-10-25 04:06:10 +0000525
Rafael Espindolac84f6082014-11-25 06:11:24 +0000526 void upgradeMismatchedGlobalArray(StringRef Name);
527 void upgradeMismatchedGlobals();
David Majnemerdad0a642014-06-27 18:19:56 +0000528
Rafael Espindolabaa3bf82015-12-01 15:19:48 +0000529 bool linkIfNeeded(GlobalValue &GV);
Rafael Espindolac84f6082014-11-25 06:11:24 +0000530 bool linkAppendingVarProto(GlobalVariable *DstGV,
531 const GlobalVariable *SrcGV);
Rafael Espindolaed6dc372014-05-09 14:39:25 +0000532
Rafael Espindolac84f6082014-11-25 06:11:24 +0000533 bool linkGlobalValueProto(GlobalValue *GV);
Rafael Espindolac84f6082014-11-25 06:11:24 +0000534 bool linkModuleFlagsMetadata();
Mikhail Glushenkov766d4892009-03-03 07:22:23 +0000535
Rafael Espindolaef237112014-12-08 18:45:16 +0000536 void linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src);
537 bool linkFunctionBody(Function &Dst, Function &Src);
538 void linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src);
539 bool linkGlobalValueBody(GlobalValue &Src);
540
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000541 /// Functions that take care of cloning a specific global value type
542 /// into the destination module.
543 GlobalVariable *copyGlobalVariableProto(TypeMapTy &TypeMap,
544 const GlobalVariable *SGVar);
545 Function *copyFunctionProto(TypeMapTy &TypeMap, const Function *SF);
546 GlobalValue *copyGlobalAliasProto(TypeMapTy &TypeMap, const GlobalAlias *SGA);
547
548 /// Helper methods to check if we are importing from or potentially
549 /// exporting from the current source module.
550 bool isPerformingImport() { return ImportFunction != nullptr; }
551 bool isModuleExporting() { return HasExportedFunctions; }
552
553 /// If we are importing from the source module, checks if we should
554 /// import SGV as a definition, otherwise import as a declaration.
555 bool doImportAsDefinition(const GlobalValue *SGV);
556
557 /// Get the name for SGV that should be used in the linked destination
558 /// module. Specifically, this handles the case where we need to rename
559 /// a local that is being promoted to global scope.
560 std::string getName(const GlobalValue *SGV);
561
562 /// Get the new linkage for SGV that should be used in the linked destination
563 /// module. Specifically, for ThinLTO importing or exporting it may need
564 /// to be adjusted.
565 GlobalValue::LinkageTypes getLinkage(const GlobalValue *SGV);
566
567 /// Copies the necessary global value attributes and name from the source
568 /// to the newly cloned global value.
569 void copyGVAttributes(GlobalValue *NewGV, const GlobalValue *SrcGV);
570
571 /// Updates the visibility for the new global cloned from the source
572 /// and, if applicable, linked with an existing destination global.
573 /// Handles visibility change required for promoted locals.
574 void setVisibility(GlobalValue *NewGV, const GlobalValue *SGV,
575 const GlobalValue *DGV = nullptr);
576
Rafael Espindolac84f6082014-11-25 06:11:24 +0000577 void linkNamedMDNodes();
578};
Alexander Kornienkof00654e2015-06-23 09:49:53 +0000579}
Bill Wendlingd48b7782012-02-28 04:01:21 +0000580
Rafael Espindola18c89412014-10-27 02:35:46 +0000581/// The LLVM SymbolTable class autorenames globals that conflict in the symbol
582/// table. This is good for all clients except for us. Go through the trouble
583/// to force this back.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000584static void forceRenaming(GlobalValue *GV, StringRef Name) {
585 // If the global doesn't force its name or if it already has the right name,
586 // there is nothing for us to do.
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000587 // Note that any required local to global promotion should already be done,
588 // so promoted locals will not skip this handling as their linkage is no
589 // longer local.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000590 if (GV->hasLocalLinkage() || GV->getName() == Name)
591 return;
592
593 Module *M = GV->getParent();
Reid Spencer361e5132004-11-12 20:37:43 +0000594
595 // If there is a conflict, rename the conflict.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000596 if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
Chris Lattner2a8d2e02007-02-11 00:39:38 +0000597 GV->takeName(ConflictGV);
598 ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000599 assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
Chris Lattner2a8d2e02007-02-11 00:39:38 +0000600 } else {
601 GV->setName(Name); // Force the name back
Reid Spencer3aaaa0b2007-02-05 20:47:22 +0000602 }
Reid Spencer3aaaa0b2007-02-05 20:47:22 +0000603}
Reid Spencer90246aa2007-02-04 04:29:21 +0000604
Rafael Espindola18c89412014-10-27 02:35:46 +0000605/// copy additional attributes (those not needed to construct a GlobalValue)
606/// from the SrcGV to the DestGV.
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000607void ModuleLinker::copyGVAttributes(GlobalValue *NewGV,
608 const GlobalValue *SrcGV) {
609 auto *GA = dyn_cast<GlobalAlias>(SrcGV);
610 // Check for the special case of converting an alias (definition) to a
611 // non-alias (declaration). This can happen when we are importing and
612 // encounter a weak_any alias (weak_any defs may not be imported, see
613 // comments in ModuleLinker::getLinkage) or an alias whose base object is
614 // being imported as a declaration. In that case copy the attributes from the
615 // base object.
616 if (GA && !dyn_cast<GlobalAlias>(NewGV)) {
Teresa Johnson3cd81612015-11-10 18:20:11 +0000617 assert(isPerformingImport() && !doImportAsDefinition(GA));
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000618 NewGV->copyAttributesFrom(GA->getBaseObject());
619 } else
620 NewGV->copyAttributesFrom(SrcGV);
621 forceRenaming(NewGV, getName(SrcGV));
Reid Spencer361e5132004-11-12 20:37:43 +0000622}
623
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000624bool ModuleLinker::doImportAsDefinition(const GlobalValue *SGV) {
625 if (!isPerformingImport())
626 return false;
Teresa Johnson3cd81612015-11-10 18:20:11 +0000627 auto *GA = dyn_cast<GlobalAlias>(SGV);
628 if (GA) {
629 if (GA->hasWeakAnyLinkage())
630 return false;
Rafael Espindola89345772015-11-26 19:22:59 +0000631 const GlobalObject *GO = GA->getBaseObject();
632 if (!GO->hasLinkOnceODRLinkage())
633 return false;
634 return doImportAsDefinition(GO);
Teresa Johnson3cd81612015-11-10 18:20:11 +0000635 }
Teresa Johnsondfbebc32015-11-10 18:26:31 +0000636 // Always import GlobalVariable definitions, except for the special
637 // case of WeakAny which are imported as ExternalWeak declarations
638 // (see comments in ModuleLinker::getLinkage). The linkage changes
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000639 // described in ModuleLinker::getLinkage ensure the correct behavior (e.g.
640 // global variables with external linkage are transformed to
Teresa Johnson3cd81612015-11-10 18:20:11 +0000641 // available_externally definitions, which are ultimately turned into
642 // declarations after the EliminateAvailableExternally pass).
Craig Topper66059c92015-11-18 07:07:59 +0000643 if (isa<GlobalVariable>(SGV) && !SGV->isDeclaration() &&
Teresa Johnson3cd81612015-11-10 18:20:11 +0000644 !SGV->hasWeakAnyLinkage())
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000645 return true;
646 // Only import the function requested for importing.
647 auto *SF = dyn_cast<Function>(SGV);
648 if (SF && SF == ImportFunction)
649 return true;
650 // Otherwise no.
651 return false;
652}
653
654bool ModuleLinker::doPromoteLocalToGlobal(const GlobalValue *SGV) {
655 assert(SGV->hasLocalLinkage());
656 // Both the imported references and the original local variable must
657 // be promoted.
658 if (!isPerformingImport() && !isModuleExporting())
659 return false;
660
661 // Local const variables never need to be promoted unless they are address
662 // taken. The imported uses can simply use the clone created in this module.
663 // For now we are conservative in determining which variables are not
664 // address taken by checking the unnamed addr flag. To be more aggressive,
665 // the address taken information must be checked earlier during parsing
666 // of the module and recorded in the function index for use when importing
667 // from that module.
668 auto *GVar = dyn_cast<GlobalVariable>(SGV);
669 if (GVar && GVar->isConstant() && GVar->hasUnnamedAddr())
670 return false;
671
672 // Eventually we only need to promote functions in the exporting module that
673 // are referenced by a potentially exported function (i.e. one that is in the
674 // function index).
675 return true;
676}
677
678std::string ModuleLinker::getName(const GlobalValue *SGV) {
679 // For locals that must be promoted to global scope, ensure that
680 // the promoted name uniquely identifies the copy in the original module,
681 // using the ID assigned during combined index creation. When importing,
682 // we rename all locals (not just those that are promoted) in order to
683 // avoid naming conflicts between locals imported from different modules.
684 if (SGV->hasLocalLinkage() &&
685 (doPromoteLocalToGlobal(SGV) || isPerformingImport()))
686 return FunctionInfoIndex::getGlobalNameForLocal(
687 SGV->getName(),
688 ImportIndex->getModuleId(SGV->getParent()->getModuleIdentifier()));
689 return SGV->getName();
690}
691
692GlobalValue::LinkageTypes ModuleLinker::getLinkage(const GlobalValue *SGV) {
693 // Any local variable that is referenced by an exported function needs
694 // to be promoted to global scope. Since we don't currently know which
695 // functions reference which local variables/functions, we must treat
696 // all as potentially exported if this module is exporting anything.
697 if (isModuleExporting()) {
698 if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV))
699 return GlobalValue::ExternalLinkage;
700 return SGV->getLinkage();
701 }
702
703 // Otherwise, if we aren't importing, no linkage change is needed.
704 if (!isPerformingImport())
705 return SGV->getLinkage();
706
707 switch (SGV->getLinkage()) {
708 case GlobalValue::ExternalLinkage:
709 // External defnitions are converted to available_externally
710 // definitions upon import, so that they are available for inlining
711 // and/or optimization, but are turned into declarations later
712 // during the EliminateAvailableExternally pass.
Teresa Johnson3cd81612015-11-10 18:20:11 +0000713 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000714 return GlobalValue::AvailableExternallyLinkage;
715 // An imported external declaration stays external.
716 return SGV->getLinkage();
717
718 case GlobalValue::AvailableExternallyLinkage:
719 // An imported available_externally definition converts
720 // to external if imported as a declaration.
721 if (!doImportAsDefinition(SGV))
722 return GlobalValue::ExternalLinkage;
723 // An imported available_externally declaration stays that way.
724 return SGV->getLinkage();
725
726 case GlobalValue::LinkOnceAnyLinkage:
727 case GlobalValue::LinkOnceODRLinkage:
728 // These both stay the same when importing the definition.
729 // The ThinLTO pass will eventually force-import their definitions.
730 return SGV->getLinkage();
731
732 case GlobalValue::WeakAnyLinkage:
733 // Can't import weak_any definitions correctly, or we might change the
734 // program semantics, since the linker will pick the first weak_any
735 // definition and importing would change the order they are seen by the
736 // linker. The module linking caller needs to enforce this.
737 assert(!doImportAsDefinition(SGV));
738 // If imported as a declaration, it becomes external_weak.
739 return GlobalValue::ExternalWeakLinkage;
740
741 case GlobalValue::WeakODRLinkage:
742 // For weak_odr linkage, there is a guarantee that all copies will be
743 // equivalent, so the issue described above for weak_any does not exist,
744 // and the definition can be imported. It can be treated similarly
745 // to an imported externally visible global value.
Teresa Johnson3cd81612015-11-10 18:20:11 +0000746 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000747 return GlobalValue::AvailableExternallyLinkage;
748 else
749 return GlobalValue::ExternalLinkage;
750
751 case GlobalValue::AppendingLinkage:
752 // It would be incorrect to import an appending linkage variable,
753 // since it would cause global constructors/destructors to be
754 // executed multiple times. This should have already been handled
755 // by linkGlobalValueProto.
Davide Italianof3d23292015-11-13 02:16:51 +0000756 llvm_unreachable("Cannot import appending linkage variable");
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000757
758 case GlobalValue::InternalLinkage:
759 case GlobalValue::PrivateLinkage:
760 // If we are promoting the local to global scope, it is handled
761 // similarly to a normal externally visible global.
762 if (doPromoteLocalToGlobal(SGV)) {
Teresa Johnson3cd81612015-11-10 18:20:11 +0000763 if (doImportAsDefinition(SGV) && !dyn_cast<GlobalAlias>(SGV))
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000764 return GlobalValue::AvailableExternallyLinkage;
765 else
766 return GlobalValue::ExternalLinkage;
767 }
768 // A non-promoted imported local definition stays local.
769 // The ThinLTO pass will eventually force-import their definitions.
770 return SGV->getLinkage();
771
772 case GlobalValue::ExternalWeakLinkage:
773 // External weak doesn't apply to definitions, must be a declaration.
774 assert(!doImportAsDefinition(SGV));
775 // Linkage stays external_weak.
776 return SGV->getLinkage();
777
778 case GlobalValue::CommonLinkage:
779 // Linkage stays common on definitions.
780 // The ThinLTO pass will eventually force-import their definitions.
781 return SGV->getLinkage();
782 }
783
784 llvm_unreachable("unknown linkage type");
785}
786
Rafael Espindolaef237112014-12-08 18:45:16 +0000787/// Loop through the global variables in the src module and merge them into the
788/// dest module.
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000789GlobalVariable *
790ModuleLinker::copyGlobalVariableProto(TypeMapTy &TypeMap,
791 const GlobalVariable *SGVar) {
Rafael Espindolaef237112014-12-08 18:45:16 +0000792 // No linking to be performed or linking from the source: simply create an
793 // identical version of the symbol over in the dest module... the
794 // initializer will be filled in later by LinkGlobalInits.
795 GlobalVariable *NewDGV = new GlobalVariable(
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000796 *DstM, TypeMap.get(SGVar->getType()->getElementType()),
797 SGVar->isConstant(), getLinkage(SGVar), /*init*/ nullptr, getName(SGVar),
798 /*insertbefore*/ nullptr, SGVar->getThreadLocalMode(),
Rafael Espindolaef237112014-12-08 18:45:16 +0000799 SGVar->getType()->getAddressSpace());
800
801 return NewDGV;
802}
803
804/// Link the function in the source module into the destination module if
805/// needed, setting up mapping information.
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000806Function *ModuleLinker::copyFunctionProto(TypeMapTy &TypeMap,
807 const Function *SF) {
Rafael Espindolaef237112014-12-08 18:45:16 +0000808 // If there is no linkage to be performed or we are linking from the source,
809 // bring SF over.
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000810 return Function::Create(TypeMap.get(SF->getFunctionType()), getLinkage(SF),
811 getName(SF), DstM);
Rafael Espindolaef237112014-12-08 18:45:16 +0000812}
813
814/// Set up prototypes for any aliases that come over from the source module.
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000815GlobalValue *ModuleLinker::copyGlobalAliasProto(TypeMapTy &TypeMap,
816 const GlobalAlias *SGA) {
817 // If we are importing and encounter a weak_any alias, or an alias to
818 // an object being imported as a declaration, we must import the alias
819 // as a declaration as well, which involves converting it to a non-alias.
820 // See comments in ModuleLinker::getLinkage for why we cannot import
821 // weak_any defintions.
Teresa Johnson3cd81612015-11-10 18:20:11 +0000822 if (isPerformingImport() && !doImportAsDefinition(SGA)) {
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000823 // Need to convert to declaration. All aliases must be definitions.
824 const GlobalValue *GVal = SGA->getBaseObject();
825 GlobalValue *NewGV;
826 if (auto *GVar = dyn_cast<GlobalVariable>(GVal))
827 NewGV = copyGlobalVariableProto(TypeMap, GVar);
828 else {
829 auto *F = dyn_cast<Function>(GVal);
830 assert(F);
831 NewGV = copyFunctionProto(TypeMap, F);
832 }
Teresa Johnsonf1b0a6e2015-11-04 16:01:16 +0000833 // Set the linkage to External or ExternalWeak (see comments in
834 // ModuleLinker::getLinkage for why WeakAny is converted to ExternalWeak).
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000835 if (SGA->hasWeakAnyLinkage())
836 NewGV->setLinkage(GlobalValue::ExternalWeakLinkage);
Teresa Johnsonf1b0a6e2015-11-04 16:01:16 +0000837 else
838 NewGV->setLinkage(GlobalValue::ExternalLinkage);
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000839 return NewGV;
840 }
Rafael Espindolaef237112014-12-08 18:45:16 +0000841 // If there is no linkage to be performed or we're linking from the source,
842 // bring over SGA.
David Blaikie6614d8d2015-09-14 20:29:26 +0000843 auto *Ty = TypeMap.get(SGA->getValueType());
844 return GlobalAlias::create(Ty, SGA->getType()->getPointerAddressSpace(),
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000845 getLinkage(SGA), getName(SGA), DstM);
Rafael Espindolaef237112014-12-08 18:45:16 +0000846}
847
Rafael Espindolaeb5e0a72015-11-29 14:33:06 +0000848static GlobalValue::VisibilityTypes
849getMinVisibility(GlobalValue::VisibilityTypes A,
850 GlobalValue::VisibilityTypes B) {
851 if (A == GlobalValue::HiddenVisibility || B == GlobalValue::HiddenVisibility)
852 return GlobalValue::HiddenVisibility;
853 if (A == GlobalValue::ProtectedVisibility ||
854 B == GlobalValue::ProtectedVisibility)
855 return GlobalValue::ProtectedVisibility;
856 return GlobalValue::DefaultVisibility;
857}
858
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000859void ModuleLinker::setVisibility(GlobalValue *NewGV, const GlobalValue *SGV,
860 const GlobalValue *DGV) {
861 GlobalValue::VisibilityTypes Visibility = SGV->getVisibility();
862 if (DGV)
Rafael Espindolaeb5e0a72015-11-29 14:33:06 +0000863 Visibility = getMinVisibility(DGV->getVisibility(), Visibility);
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000864 // For promoted locals, mark them hidden so that they can later be
865 // stripped from the symbol table to reduce bloat.
866 if (SGV->hasLocalLinkage() && doPromoteLocalToGlobal(SGV))
867 Visibility = GlobalValue::HiddenVisibility;
868 NewGV->setVisibility(Visibility);
869}
870
871GlobalValue *ModuleLinker::copyGlobalValueProto(TypeMapTy &TypeMap,
872 const GlobalValue *SGV,
873 const GlobalValue *DGV) {
Rafael Espindolaef237112014-12-08 18:45:16 +0000874 GlobalValue *NewGV;
875 if (auto *SGVar = dyn_cast<GlobalVariable>(SGV))
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000876 NewGV = copyGlobalVariableProto(TypeMap, SGVar);
Rafael Espindolaef237112014-12-08 18:45:16 +0000877 else if (auto *SF = dyn_cast<Function>(SGV))
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000878 NewGV = copyFunctionProto(TypeMap, SF);
Rafael Espindolaef237112014-12-08 18:45:16 +0000879 else
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000880 NewGV = copyGlobalAliasProto(TypeMap, cast<GlobalAlias>(SGV));
Rafael Espindolaef237112014-12-08 18:45:16 +0000881 copyGVAttributes(NewGV, SGV);
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +0000882 setVisibility(NewGV, SGV, DGV);
Rafael Espindolaef237112014-12-08 18:45:16 +0000883 return NewGV;
884}
885
Rafael Espindola19b52382015-11-27 20:28:19 +0000886Value *ValueMaterializerTy::materializeDeclFor(Value *V) {
887 return ModLinker->materializeDeclFor(V);
888}
889
890Value *ModuleLinker::materializeDeclFor(Value *V) {
Rafael Espindolaef237112014-12-08 18:45:16 +0000891 auto *SGV = dyn_cast<GlobalValue>(V);
892 if (!SGV)
Craig Topper2617dcc2014-04-15 06:32:26 +0000893 return nullptr;
James Molloyf6f121e2013-05-28 15:17:05 +0000894
Teresa Johnson10632932015-11-06 17:50:53 +0000895 // If we are done linking global value bodies (i.e. we are performing
896 // metadata linking), don't link in the global value due to this
897 // reference, simply map it to null.
Rafael Espindola19b52382015-11-27 20:28:19 +0000898 if (doneLinkingBodies())
Teresa Johnson10632932015-11-06 17:50:53 +0000899 return nullptr;
900
Rafael Espindolabaa3bf82015-12-01 15:19:48 +0000901 linkGlobalValueProto(SGV);
902 if (HasError)
903 return nullptr;
904 Value *Ret = ValueMap[SGV];
905 assert(Ret);
906 return Ret;
James Molloyf6f121e2013-05-28 15:17:05 +0000907}
908
Rafael Espindola19b52382015-11-27 20:28:19 +0000909void ValueMaterializerTy::materializeInitFor(GlobalValue *New,
910 GlobalValue *Old) {
911 return ModLinker->materializeInitFor(New, Old);
912}
913
914void ModuleLinker::materializeInitFor(GlobalValue *New, GlobalValue *Old) {
Rafael Espindolabaa3bf82015-12-01 15:19:48 +0000915 if (auto *F = dyn_cast<Function>(New)) {
916 if (!F->isDeclaration())
917 return;
918 } else if (auto *V = dyn_cast<GlobalVariable>(New)) {
919 if (V->hasInitializer())
920 return;
921 } else {
922 auto *A = cast<GlobalAlias>(New);
923 if (A->getAliasee())
924 return;
925 }
926
927 if (Old->isDeclaration())
928 return;
929
Rafael Espindola19b52382015-11-27 20:28:19 +0000930 if (isPerformingImport() && !doImportAsDefinition(Old))
931 return;
932
Rafael Espindolabaa3bf82015-12-01 15:19:48 +0000933 if (!New->hasLocalLinkage() && DoNotLinkFromSource.count(Old))
Rafael Espindola19b52382015-11-27 20:28:19 +0000934 return;
935
Rafael Espindola19b52382015-11-27 20:28:19 +0000936 linkGlobalValueBody(*Old);
937}
938
David Majnemerdad0a642014-06-27 18:19:56 +0000939bool ModuleLinker::getComdatLeader(Module *M, StringRef ComdatName,
940 const GlobalVariable *&GVar) {
941 const GlobalValue *GVal = M->getNamedValue(ComdatName);
942 if (const auto *GA = dyn_cast_or_null<GlobalAlias>(GVal)) {
943 GVal = GA->getBaseObject();
944 if (!GVal)
945 // We cannot resolve the size of the aliasee yet.
946 return emitError("Linking COMDATs named '" + ComdatName +
947 "': COMDAT key involves incomputable alias size.");
948 }
949
950 GVar = dyn_cast_or_null<GlobalVariable>(GVal);
951 if (!GVar)
952 return emitError(
953 "Linking COMDATs named '" + ComdatName +
954 "': GlobalVariable required for data dependent selection!");
955
956 return false;
957}
958
959bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName,
960 Comdat::SelectionKind Src,
961 Comdat::SelectionKind Dst,
962 Comdat::SelectionKind &Result,
963 bool &LinkFromSrc) {
964 // The ability to mix Comdat::SelectionKind::Any with
965 // Comdat::SelectionKind::Largest is a behavior that comes from COFF.
966 bool DstAnyOrLargest = Dst == Comdat::SelectionKind::Any ||
967 Dst == Comdat::SelectionKind::Largest;
968 bool SrcAnyOrLargest = Src == Comdat::SelectionKind::Any ||
969 Src == Comdat::SelectionKind::Largest;
970 if (DstAnyOrLargest && SrcAnyOrLargest) {
971 if (Dst == Comdat::SelectionKind::Largest ||
972 Src == Comdat::SelectionKind::Largest)
973 Result = Comdat::SelectionKind::Largest;
974 else
975 Result = Comdat::SelectionKind::Any;
976 } else if (Src == Dst) {
977 Result = Dst;
978 } else {
979 return emitError("Linking COMDATs named '" + ComdatName +
980 "': invalid selection kinds!");
981 }
982
983 switch (Result) {
984 case Comdat::SelectionKind::Any:
985 // Go with Dst.
986 LinkFromSrc = false;
987 break;
988 case Comdat::SelectionKind::NoDuplicates:
989 return emitError("Linking COMDATs named '" + ComdatName +
990 "': noduplicates has been violated!");
991 case Comdat::SelectionKind::ExactMatch:
992 case Comdat::SelectionKind::Largest:
993 case Comdat::SelectionKind::SameSize: {
994 const GlobalVariable *DstGV;
995 const GlobalVariable *SrcGV;
996 if (getComdatLeader(DstM, ComdatName, DstGV) ||
997 getComdatLeader(SrcM, ComdatName, SrcGV))
998 return true;
999
Mehdi Amini46a43552015-03-04 18:43:29 +00001000 const DataLayout &DstDL = DstM->getDataLayout();
1001 const DataLayout &SrcDL = SrcM->getDataLayout();
David Majnemerdad0a642014-06-27 18:19:56 +00001002 uint64_t DstSize =
Mehdi Amini46a43552015-03-04 18:43:29 +00001003 DstDL.getTypeAllocSize(DstGV->getType()->getPointerElementType());
David Majnemerdad0a642014-06-27 18:19:56 +00001004 uint64_t SrcSize =
Mehdi Amini46a43552015-03-04 18:43:29 +00001005 SrcDL.getTypeAllocSize(SrcGV->getType()->getPointerElementType());
David Majnemerdad0a642014-06-27 18:19:56 +00001006 if (Result == Comdat::SelectionKind::ExactMatch) {
1007 if (SrcGV->getInitializer() != DstGV->getInitializer())
1008 return emitError("Linking COMDATs named '" + ComdatName +
1009 "': ExactMatch violated!");
1010 LinkFromSrc = false;
1011 } else if (Result == Comdat::SelectionKind::Largest) {
1012 LinkFromSrc = SrcSize > DstSize;
1013 } else if (Result == Comdat::SelectionKind::SameSize) {
1014 if (SrcSize != DstSize)
1015 return emitError("Linking COMDATs named '" + ComdatName +
1016 "': SameSize violated!");
1017 LinkFromSrc = false;
1018 } else {
1019 llvm_unreachable("unknown selection kind");
1020 }
1021 break;
1022 }
1023 }
1024
1025 return false;
1026}
1027
1028bool ModuleLinker::getComdatResult(const Comdat *SrcC,
1029 Comdat::SelectionKind &Result,
1030 bool &LinkFromSrc) {
Rafael Espindolab16196a2014-08-11 17:07:34 +00001031 Comdat::SelectionKind SSK = SrcC->getSelectionKind();
David Majnemerdad0a642014-06-27 18:19:56 +00001032 StringRef ComdatName = SrcC->getName();
1033 Module::ComdatSymTabType &ComdatSymTab = DstM->getComdatSymbolTable();
1034 Module::ComdatSymTabType::iterator DstCI = ComdatSymTab.find(ComdatName);
Rafael Espindola2ef3f292014-08-11 16:55:42 +00001035
Rafael Espindolab16196a2014-08-11 17:07:34 +00001036 if (DstCI == ComdatSymTab.end()) {
1037 // Use the comdat if it is only available in one of the modules.
1038 LinkFromSrc = true;
1039 Result = SSK;
Rafael Espindola2ef3f292014-08-11 16:55:42 +00001040 return false;
Rafael Espindolab16196a2014-08-11 17:07:34 +00001041 }
Rafael Espindola2ef3f292014-08-11 16:55:42 +00001042
1043 const Comdat *DstC = &DstCI->second;
Rafael Espindola2ef3f292014-08-11 16:55:42 +00001044 Comdat::SelectionKind DSK = DstC->getSelectionKind();
1045 return computeResultingSelectionKind(ComdatName, SSK, DSK, Result,
1046 LinkFromSrc);
David Majnemerdad0a642014-06-27 18:19:56 +00001047}
James Molloyf6f121e2013-05-28 15:17:05 +00001048
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001049bool ModuleLinker::shouldLinkFromSource(bool &LinkFromSrc,
1050 const GlobalValue &Dest,
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001051 const GlobalValue &Src) {
Duncan P. N. Exon Smithe8681232015-04-22 04:11:00 +00001052 // Should we unconditionally use the Src?
Artem Belevich020d4fb2015-09-01 17:55:55 +00001053 if (shouldOverrideFromSrc()) {
Duncan P. N. Exon Smithe8681232015-04-22 04:11:00 +00001054 LinkFromSrc = true;
1055 return false;
1056 }
1057
Rafael Espindola778fcc72014-11-02 13:28:57 +00001058 // We always have to add Src if it has appending linkage.
1059 if (Src.hasAppendingLinkage()) {
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00001060 // Caller should have already determined that we can't link from source
1061 // when importing (see comments in linkGlobalValueProto).
1062 assert(!isPerformingImport());
Rafael Espindola778fcc72014-11-02 13:28:57 +00001063 LinkFromSrc = true;
1064 return false;
1065 }
1066
Rafael Espindolad4bcefc2014-10-24 18:13:04 +00001067 bool SrcIsDeclaration = Src.isDeclarationForLinker();
1068 bool DestIsDeclaration = Dest.isDeclarationForLinker();
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001069
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00001070 if (isPerformingImport()) {
1071 if (isa<Function>(&Src)) {
1072 // For functions, LinkFromSrc iff this is the function requested
1073 // for importing. For variables, decide below normally.
1074 LinkFromSrc = (&Src == ImportFunction);
1075 return false;
1076 }
1077
1078 // Check if this is an alias with an already existing definition
1079 // in Dest, which must have come from a prior importing pass from
1080 // the same Src module. Unlike imported function and variable
1081 // definitions, which are imported as available_externally and are
1082 // not definitions for the linker, that is not a valid linkage for
1083 // imported aliases which must be definitions. Simply use the existing
1084 // Dest copy.
1085 if (isa<GlobalAlias>(&Src) && !DestIsDeclaration) {
1086 assert(isa<GlobalAlias>(&Dest));
1087 LinkFromSrc = false;
1088 return false;
1089 }
1090 }
1091
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001092 if (SrcIsDeclaration) {
1093 // If Src is external or if both Src & Dest are external.. Just link the
1094 // external globals, we aren't adding anything.
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001095 if (Src.hasDLLImportStorageClass()) {
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001096 // If one of GVs is marked as DLLImport, result should be dllimport'ed.
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001097 LinkFromSrc = DestIsDeclaration;
1098 return false;
1099 }
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001100 // If the Dest is weak, use the source linkage.
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001101 LinkFromSrc = Dest.hasExternalWeakLinkage();
1102 return false;
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001103 }
1104
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001105 if (DestIsDeclaration) {
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001106 // If Dest is external but Src is not:
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001107 LinkFromSrc = true;
1108 return false;
1109 }
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001110
Rafael Espindola09106052014-09-09 15:59:12 +00001111 if (Src.hasCommonLinkage()) {
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001112 if (Dest.hasLinkOnceLinkage() || Dest.hasWeakLinkage()) {
1113 LinkFromSrc = true;
Rafael Espindola09106052014-09-09 15:59:12 +00001114 return false;
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001115 }
1116
1117 if (!Dest.hasCommonLinkage()) {
1118 LinkFromSrc = false;
1119 return false;
1120 }
Rafael Espindola09106052014-09-09 15:59:12 +00001121
Mehdi Aminia28d91d2015-03-10 02:37:25 +00001122 const DataLayout &DL = Dest.getParent()->getDataLayout();
Rafael Espindola09106052014-09-09 15:59:12 +00001123 uint64_t DestSize = DL.getTypeAllocSize(Dest.getType()->getElementType());
1124 uint64_t SrcSize = DL.getTypeAllocSize(Src.getType()->getElementType());
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001125 LinkFromSrc = SrcSize > DestSize;
1126 return false;
Rafael Espindola09106052014-09-09 15:59:12 +00001127 }
1128
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001129 if (Src.isWeakForLinker()) {
1130 assert(!Dest.hasExternalWeakLinkage());
1131 assert(!Dest.hasAvailableExternallyLinkage());
Rafael Espindola09106052014-09-09 15:59:12 +00001132
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001133 if (Dest.hasLinkOnceLinkage() && Src.hasWeakLinkage()) {
1134 LinkFromSrc = true;
1135 return false;
1136 }
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001137
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001138 LinkFromSrc = false;
Rafael Espindola09106052014-09-09 15:59:12 +00001139 return false;
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001140 }
1141
1142 if (Dest.isWeakForLinker()) {
1143 assert(Src.hasExternalLinkage());
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001144 LinkFromSrc = true;
1145 return false;
Rafael Espindoladbb0bd12014-09-09 15:21:00 +00001146 }
1147
1148 assert(!Src.hasExternalWeakLinkage());
1149 assert(!Dest.hasExternalWeakLinkage());
1150 assert(Dest.hasExternalLinkage() && Src.hasExternalLinkage() &&
1151 "Unexpected linkage type!");
1152 return emitError("Linking globals named '" + Src.getName() +
1153 "': symbol multiply defined!");
1154}
1155
Rafael Espindola18c89412014-10-27 02:35:46 +00001156/// Loop over all of the linked values to compute type mappings. For example,
1157/// if we link "extern Foo *x" and "Foo *x = NULL", then we have two struct
1158/// types 'Foo' but one got renamed when the module was loaded into the same
1159/// LLVMContext.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001160void ModuleLinker::computeTypeMapping() {
Rafael Espindolac8a476e2014-11-25 04:26:19 +00001161 for (GlobalValue &SGV : SrcM->globals()) {
1162 GlobalValue *DGV = getLinkedToGlobal(&SGV);
1163 if (!DGV)
1164 continue;
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001165
Rafael Espindolac8a476e2014-11-25 04:26:19 +00001166 if (!DGV->hasAppendingLinkage() || !SGV.hasAppendingLinkage()) {
1167 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001168 continue;
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001169 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001170
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001171 // Unify the element type of appending arrays.
1172 ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
Rafael Espindolac8a476e2014-11-25 04:26:19 +00001173 ArrayType *SAT = cast<ArrayType>(SGV.getType()->getElementType());
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001174 TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
Devang Patel5c310be2009-08-11 18:01:24 +00001175 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001176
Rafael Espindolac8a476e2014-11-25 04:26:19 +00001177 for (GlobalValue &SGV : *SrcM) {
1178 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1179 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001180 }
Bill Wendling7b464612012-02-27 22:34:19 +00001181
Rafael Espindolae96d7eb2014-11-25 04:43:59 +00001182 for (GlobalValue &SGV : SrcM->aliases()) {
1183 if (GlobalValue *DGV = getLinkedToGlobal(&SGV))
1184 TypeMap.addTypeMapping(DGV->getType(), SGV.getType());
1185 }
1186
Bill Wendlingd48b7782012-02-28 04:01:21 +00001187 // Incorporate types by name, scanning all the types in the source module.
1188 // At this point, the destination module may have a type "%foo = { i32 }" for
Bill Wendling2b3f61a2012-02-27 23:48:30 +00001189 // example. When the source module got loaded into the same LLVMContext, if
1190 // it had the same type, it would have been renamed to "%foo.42 = { i32 }".
Rafael Espindola2fa1e432014-12-03 07:18:23 +00001191 std::vector<StructType *> Types = SrcM->getIdentifiedStructTypes();
1192 for (StructType *ST : Types) {
Rafael Espindola4d4c9382014-12-01 19:08:07 +00001193 if (!ST->hasName())
1194 continue;
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001195
Bill Wendling2b3f61a2012-02-27 23:48:30 +00001196 // Check to see if there is a dot in the name followed by a digit.
Bill Wendlingd48b7782012-02-28 04:01:21 +00001197 size_t DotPos = ST->getName().rfind('.');
1198 if (DotPos == 0 || DotPos == StringRef::npos ||
Guy Benyei83c74e92013-02-12 21:21:59 +00001199 ST->getName().back() == '.' ||
Rafael Espindola973b3612014-12-01 19:17:46 +00001200 !isdigit(static_cast<unsigned char>(ST->getName()[DotPos + 1])))
Bill Wendlingd48b7782012-02-28 04:01:21 +00001201 continue;
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001202
Bill Wendling2b3f61a2012-02-27 23:48:30 +00001203 // Check to see if the destination module has a struct with the prefix name.
Rafael Espindola973b3612014-12-01 19:17:46 +00001204 StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos));
1205 if (!DST)
1206 continue;
1207
1208 // Don't use it if this actually came from the source module. They're in
1209 // the same LLVMContext after all. Also don't use it unless the type is
1210 // actually used in the destination module. This can happen in situations
1211 // like this:
1212 //
1213 // Module A Module B
1214 // -------- --------
1215 // %Z = type { %A } %B = type { %C.1 }
1216 // %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
1217 // %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
1218 // %C = type { i8* } %B.3 = type { %C.1 }
1219 //
1220 // When we link Module B with Module A, the '%B' in Module B is
1221 // used. However, that would then use '%C.1'. But when we process '%C.1',
1222 // we prefer to take the '%C' version. So we are then left with both
1223 // '%C.1' and '%C' being used for the same types. This leads to some
1224 // variables using one type and some using the other.
Rafael Espindola31ad4682014-12-03 22:36:37 +00001225 if (TypeMap.DstStructTypesSet.hasType(DST))
Rafael Espindola973b3612014-12-01 19:17:46 +00001226 TypeMap.addTypeMapping(DST, ST);
Bill Wendling2b3f61a2012-02-27 23:48:30 +00001227 }
1228
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001229 // Now that we have discovered all of the type equivalences, get a body for
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001230 // any 'opaque' types in the dest module that are now resolved.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001231 TypeMap.linkDefinedTypeBodies();
Devang Patel5c310be2009-08-11 18:01:24 +00001232}
1233
Duncan P. N. Exon Smith09d84ad2014-08-12 16:46:37 +00001234static void upgradeGlobalArray(GlobalVariable *GV) {
1235 ArrayType *ATy = cast<ArrayType>(GV->getType()->getElementType());
1236 StructType *OldTy = cast<StructType>(ATy->getElementType());
1237 assert(OldTy->getNumElements() == 2 && "Expected to upgrade from 2 elements");
1238
1239 // Get the upgraded 3 element type.
1240 PointerType *VoidPtrTy = Type::getInt8Ty(GV->getContext())->getPointerTo();
1241 Type *Tys[3] = {OldTy->getElementType(0), OldTy->getElementType(1),
1242 VoidPtrTy};
1243 StructType *NewTy = StructType::get(GV->getContext(), Tys, false);
1244
1245 // Build new constants with a null third field filled in.
1246 Constant *OldInitC = GV->getInitializer();
1247 ConstantArray *OldInit = dyn_cast<ConstantArray>(OldInitC);
1248 if (!OldInit && !isa<ConstantAggregateZero>(OldInitC))
1249 // Invalid initializer; give up.
1250 return;
1251 std::vector<Constant *> Initializers;
1252 if (OldInit && OldInit->getNumOperands()) {
1253 Value *Null = Constant::getNullValue(VoidPtrTy);
1254 for (Use &U : OldInit->operands()) {
1255 ConstantStruct *Init = cast<ConstantStruct>(U.get());
1256 Initializers.push_back(ConstantStruct::get(
1257 NewTy, Init->getOperand(0), Init->getOperand(1), Null, nullptr));
1258 }
1259 }
1260 assert(Initializers.size() == ATy->getNumElements() &&
1261 "Failed to copy all array elements");
1262
1263 // Replace the old GV with a new one.
1264 ATy = ArrayType::get(NewTy, Initializers.size());
1265 Constant *NewInit = ConstantArray::get(ATy, Initializers);
1266 GlobalVariable *NewGV = new GlobalVariable(
1267 *GV->getParent(), ATy, GV->isConstant(), GV->getLinkage(), NewInit, "",
1268 GV, GV->getThreadLocalMode(), GV->getType()->getAddressSpace(),
1269 GV->isExternallyInitialized());
1270 NewGV->copyAttributesFrom(GV);
1271 NewGV->takeName(GV);
1272 assert(GV->use_empty() && "program cannot use initializer list");
1273 GV->eraseFromParent();
1274}
1275
1276void ModuleLinker::upgradeMismatchedGlobalArray(StringRef Name) {
1277 // Look for the global arrays.
1278 auto *DstGV = dyn_cast_or_null<GlobalVariable>(DstM->getNamedValue(Name));
1279 if (!DstGV)
1280 return;
1281 auto *SrcGV = dyn_cast_or_null<GlobalVariable>(SrcM->getNamedValue(Name));
1282 if (!SrcGV)
1283 return;
1284
1285 // Check if the types already match.
1286 auto *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
1287 auto *SrcTy =
1288 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1289 if (DstTy == SrcTy)
1290 return;
1291
1292 // Grab the element types. We can only upgrade an array of a two-field
1293 // struct. Only bother if the other one has three-fields.
1294 auto *DstEltTy = cast<StructType>(DstTy->getElementType());
1295 auto *SrcEltTy = cast<StructType>(SrcTy->getElementType());
1296 if (DstEltTy->getNumElements() == 2 && SrcEltTy->getNumElements() == 3) {
1297 upgradeGlobalArray(DstGV);
1298 return;
1299 }
1300 if (DstEltTy->getNumElements() == 3 && SrcEltTy->getNumElements() == 2)
1301 upgradeGlobalArray(SrcGV);
1302
1303 // We can't upgrade any other differences.
1304}
1305
1306void ModuleLinker::upgradeMismatchedGlobals() {
1307 upgradeMismatchedGlobalArray("llvm.global_ctors");
1308 upgradeMismatchedGlobalArray("llvm.global_dtors");
1309}
1310
Rafael Espindola6e8ab922015-12-01 17:17:04 +00001311static void getArrayElements(const Constant *C,
1312 SmallVectorImpl<Constant *> &Dest) {
1313 unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
1314
1315 for (unsigned i = 0; i != NumElements; ++i)
1316 Dest.push_back(C->getAggregateElement(i));
1317}
1318
Rafael Espindola18c89412014-10-27 02:35:46 +00001319/// If there were any appending global variables, link them together now.
1320/// Return true on error.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001321bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
Rafael Espindola3e8bc6a2014-10-31 16:08:17 +00001322 const GlobalVariable *SrcGV) {
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001323 ArrayType *SrcTy =
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001324 cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
1325 Type *EltTy = SrcTy->getElementType();
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001326
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001327 if (DstGV) {
1328 ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001329
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001330 if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
1331 return emitError(
1332 "Linking globals named '" + SrcGV->getName() +
1333 "': can only link appending global with another appending global!");
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001334
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001335 // Check to see that they two arrays agree on type.
1336 if (EltTy != DstTy->getElementType())
1337 return emitError("Appending variables with different element types!");
1338 if (DstGV->isConstant() != SrcGV->isConstant())
1339 return emitError("Appending variables linked with different const'ness!");
Rafael Espindolafac3a012013-09-04 15:33:34 +00001340
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001341 if (DstGV->getAlignment() != SrcGV->getAlignment())
1342 return emitError(
1343 "Appending variables with different alignment need to be linked!");
Rafael Espindolafac3a012013-09-04 15:33:34 +00001344
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001345 if (DstGV->getVisibility() != SrcGV->getVisibility())
1346 return emitError(
1347 "Appending variables with different visibility need to be linked!");
1348
1349 if (DstGV->hasUnnamedAddr() != SrcGV->hasUnnamedAddr())
1350 return emitError(
1351 "Appending variables with different unnamed_addr need to be linked!");
1352
1353 if (StringRef(DstGV->getSection()) != SrcGV->getSection())
1354 return emitError(
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001355 "Appending variables with different section name need to be linked!");
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001356 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001357
Rafael Espindola6e8ab922015-12-01 17:17:04 +00001358 SmallVector<Constant *, 16> DstElements;
1359 if (DstGV)
1360 getArrayElements(DstGV->getInitializer(), DstElements);
1361
1362 SmallVector<Constant *, 16> SrcElements;
1363 getArrayElements(SrcGV->getInitializer(), SrcElements);
1364
1365 StringRef Name = SrcGV->getName();
1366 bool IsNewStructor =
1367 (Name == "llvm.global_ctors" || Name == "llvm.global_dtors") &&
1368 cast<StructType>(EltTy)->getNumElements() == 3;
1369 if (IsNewStructor)
1370 SrcElements.erase(
1371 std::remove_if(SrcElements.begin(), SrcElements.end(),
1372 [this](Constant *E) {
1373 auto *Key = dyn_cast<GlobalValue>(
1374 E->getAggregateElement(2)->stripPointerCasts());
1375 return DoNotLinkFromSource.count(Key);
1376 }),
1377 SrcElements.end());
1378 uint64_t NewSize = DstElements.size() + SrcElements.size();
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001379 ArrayType *NewType = ArrayType::get(EltTy, NewSize);
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001380
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001381 // Create the new global variable.
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001382 GlobalVariable *NG = new GlobalVariable(
1383 *DstM, NewType, SrcGV->isConstant(), SrcGV->getLinkage(),
1384 /*init*/ nullptr, /*name*/ "", DstGV, SrcGV->getThreadLocalMode(),
1385 SrcGV->getType()->getAddressSpace());
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001386
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001387 // Propagate alignment, visibility and section info.
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001388 copyGVAttributes(NG, SrcGV);
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001389
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001390 // Replace any uses of the two global variables with uses of the new
1391 // global.
1392 ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
Anton Korobeynikove79f4c72008-03-10 22:34:28 +00001393
Rafael Espindola6e8ab922015-12-01 17:17:04 +00001394 for (auto *V : SrcElements) {
1395 DstElements.push_back(
1396 MapValue(V, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
1397 }
1398
1399 NG->setInitializer(ConstantArray::get(NewType, DstElements));
1400
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001401 if (DstGV) {
1402 DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
1403 DstGV->eraseFromParent();
1404 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001405
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001406 return false;
1407}
Mikhail Glushenkov766d4892009-03-03 07:22:23 +00001408
Rafael Espindola778fcc72014-11-02 13:28:57 +00001409bool ModuleLinker::linkGlobalValueProto(GlobalValue *SGV) {
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001410 GlobalValue *DGV = getLinkedToGlobal(SGV);
Mikhail Glushenkov766d4892009-03-03 07:22:23 +00001411
Rafael Espindola778fcc72014-11-02 13:28:57 +00001412 // Handle the ultra special appending linkage case first.
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00001413 assert(!DGV || SGV->hasAppendingLinkage() == DGV->hasAppendingLinkage());
1414 if (SGV->hasAppendingLinkage() && isPerformingImport()) {
1415 // Don't want to append to global_ctors list, for example, when we
1416 // are importing for ThinLTO, otherwise the global ctors and dtors
1417 // get executed multiple times for local variables (the latter causing
1418 // double frees).
1419 DoNotLinkFromSource.insert(SGV);
1420 return false;
1421 }
Rafael Espindolac945c8d2015-11-29 03:29:42 +00001422 if (SGV->hasAppendingLinkage())
1423 return linkAppendingVarProto(cast_or_null<GlobalVariable>(DGV),
Rafael Espindola778fcc72014-11-02 13:28:57 +00001424 cast<GlobalVariable>(SGV));
1425
1426 bool LinkFromSrc = true;
1427 Comdat *C = nullptr;
Rafael Espindola778fcc72014-11-02 13:28:57 +00001428 bool HasUnnamedAddr = SGV->hasUnnamedAddr();
1429
David Majnemerdad0a642014-06-27 18:19:56 +00001430 if (const Comdat *SC = SGV->getComdat()) {
1431 Comdat::SelectionKind SK;
1432 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
Rafael Espindola778fcc72014-11-02 13:28:57 +00001433 C = DstM->getOrInsertComdat(SC->getName());
1434 C->setSelectionKind(SK);
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001435 if (SGV->hasInternalLinkage())
1436 LinkFromSrc = true;
Rafael Espindola778fcc72014-11-02 13:28:57 +00001437 } else if (DGV) {
1438 if (shouldLinkFromSource(LinkFromSrc, *DGV, *SGV))
1439 return true;
1440 }
1441
1442 if (!LinkFromSrc) {
1443 // Track the source global so that we don't attempt to copy it over when
1444 // processing global initializers.
1445 DoNotLinkFromSource.insert(SGV);
1446
1447 if (DGV)
1448 // Make sure to remember this mapping.
1449 ValueMap[SGV] =
1450 ConstantExpr::getBitCast(DGV, TypeMap.get(SGV->getType()));
David Majnemerdad0a642014-06-27 18:19:56 +00001451 }
1452
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00001453 if (DGV)
Rafael Espindola778fcc72014-11-02 13:28:57 +00001454 HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001455
Rafael Espindola778fcc72014-11-02 13:28:57 +00001456 GlobalValue *NewGV;
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001457 if (!LinkFromSrc && DGV) {
Rafael Espindola26c29512014-12-05 17:53:15 +00001458 NewGV = DGV;
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00001459 // When linking from source we setVisibility from copyGlobalValueProto.
1460 setVisibility(NewGV, SGV, DGV);
Rafael Espindola26c29512014-12-05 17:53:15 +00001461 } else {
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00001462 NewGV = copyGlobalValueProto(TypeMap, SGV, DGV);
Teresa Johnson3cd81612015-11-10 18:20:11 +00001463
1464 if (isPerformingImport() && !doImportAsDefinition(SGV))
1465 DoNotLinkFromSource.insert(SGV);
Rafael Espindola26c29512014-12-05 17:53:15 +00001466 }
Rafael Espindolafe3842c2014-09-09 17:48:18 +00001467
Rafael Espindolaad9d0ca2014-12-05 15:42:30 +00001468 NewGV->setUnnamedAddr(HasUnnamedAddr);
Rafael Espindola439835a2014-12-05 00:09:02 +00001469
Rafael Espindolaad9d0ca2014-12-05 15:42:30 +00001470 if (auto *NewGO = dyn_cast<GlobalObject>(NewGV)) {
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001471 if (C && LinkFromSrc)
Rafael Espindolaad9d0ca2014-12-05 15:42:30 +00001472 NewGO->setComdat(C);
1473
1474 if (DGV && DGV->hasCommonLinkage() && SGV->hasCommonLinkage())
1475 NewGO->setAlignment(std::max(DGV->getAlignment(), SGV->getAlignment()));
1476 }
1477
Rafael Espindola879aeb72014-12-05 16:05:19 +00001478 if (auto *NewGVar = dyn_cast<GlobalVariable>(NewGV)) {
1479 auto *DGVar = dyn_cast_or_null<GlobalVariable>(DGV);
1480 auto *SGVar = dyn_cast<GlobalVariable>(SGV);
1481 if (DGVar && SGVar && DGVar->isDeclaration() && SGVar->isDeclaration() &&
1482 (!DGVar->isConstant() || !SGVar->isConstant()))
1483 NewGVar->setConstant(false);
1484 }
1485
Rafael Espindolaad9d0ca2014-12-05 15:42:30 +00001486 // Make sure to remember this mapping.
1487 if (NewGV != DGV) {
1488 if (DGV) {
1489 DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewGV, DGV->getType()));
1490 DGV->eraseFromParent();
Chandler Carruthfd38af22014-11-02 09:10:31 +00001491 }
Rafael Espindolaad9d0ca2014-12-05 15:42:30 +00001492 ValueMap[SGV] = NewGV;
Reid Spencer361e5132004-11-12 20:37:43 +00001493 }
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001494
Rafael Espindola778fcc72014-11-02 13:28:57 +00001495 return false;
1496}
1497
Rafael Espindola18c89412014-10-27 02:35:46 +00001498/// Update the initializers in the Dest module now that all globals that may be
1499/// referenced are in Dest.
Rafael Espindolaef237112014-12-08 18:45:16 +00001500void ModuleLinker::linkGlobalInit(GlobalVariable &Dst, GlobalVariable &Src) {
1501 // Figure out what the initializer looks like in the dest module.
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001502 Dst.setInitializer(MapValue(Src.getInitializer(), ValueMap,
1503 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
Reid Spencer361e5132004-11-12 20:37:43 +00001504}
1505
Rafael Espindola18c89412014-10-27 02:35:46 +00001506/// Copy the source function over into the dest function and fix up references
1507/// to values. At this point we know that Dest is an external function, and
1508/// that Src is not.
Rafael Espindolaef237112014-12-08 18:45:16 +00001509bool ModuleLinker::linkFunctionBody(Function &Dst, Function &Src) {
1510 assert(Dst.isDeclaration() && !Src.isDeclaration());
Reid Spencer361e5132004-11-12 20:37:43 +00001511
Rafael Espindola40d7ebe2014-12-08 13:29:33 +00001512 // Materialize if needed.
Rafael Espindola3519da82014-12-08 14:25:26 +00001513 if (std::error_code EC = Src.materialize())
Rafael Espindola40d7ebe2014-12-08 13:29:33 +00001514 return emitError(EC.message());
1515
Rafael Espindola869d1ce2014-12-08 13:44:38 +00001516 // Link in the prefix data.
Rafael Espindola3519da82014-12-08 14:25:26 +00001517 if (Src.hasPrefixData())
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001518 Dst.setPrefixData(MapValue(Src.getPrefixData(), ValueMap,
1519 RF_MoveDistinctMDs, &TypeMap, &ValMaterializer));
Rafael Espindola869d1ce2014-12-08 13:44:38 +00001520
1521 // Link in the prologue data.
Rafael Espindola3519da82014-12-08 14:25:26 +00001522 if (Src.hasPrologueData())
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001523 Dst.setPrologueData(MapValue(Src.getPrologueData(), ValueMap,
1524 RF_MoveDistinctMDs, &TypeMap,
1525 &ValMaterializer));
Rafael Espindola869d1ce2014-12-08 13:44:38 +00001526
David Majnemer7fddecc2015-06-17 20:52:32 +00001527 // Link in the personality function.
1528 if (Src.hasPersonalityFn())
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001529 Dst.setPersonalityFn(MapValue(Src.getPersonalityFn(), ValueMap,
1530 RF_MoveDistinctMDs, &TypeMap,
1531 &ValMaterializer));
David Majnemer7fddecc2015-06-17 20:52:32 +00001532
Chris Lattner7391dde2004-11-16 17:12:38 +00001533 // Go through and convert function arguments over, remembering the mapping.
Rafael Espindolaef237112014-12-08 18:45:16 +00001534 Function::arg_iterator DI = Dst.arg_begin();
Rafael Espindola3519da82014-12-08 14:25:26 +00001535 for (Argument &Arg : Src.args()) {
Rafael Espindolaa314d1a2014-12-08 14:20:10 +00001536 DI->setName(Arg.getName()); // Copy the name over.
Reid Spencer361e5132004-11-12 20:37:43 +00001537
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001538 // Add a mapping to our mapping.
Duncan P. N. Exon Smith9934b262015-10-19 22:23:36 +00001539 ValueMap[&Arg] = &*DI;
Rafael Espindolaa314d1a2014-12-08 14:20:10 +00001540 ++DI;
Reid Spencer361e5132004-11-12 20:37:43 +00001541 }
1542
Duncan P. N. Exon Smithc8d987b2015-04-24 22:07:31 +00001543 // Copy over the metadata attachments.
1544 SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
1545 Src.getAllMetadata(MDs);
1546 for (const auto &I : MDs)
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001547 Dst.setMetadata(I.first, MapMetadata(I.second, ValueMap, RF_MoveDistinctMDs,
1548 &TypeMap, &ValMaterializer));
Duncan P. N. Exon Smithc8d987b2015-04-24 22:07:31 +00001549
Rafael Espindola9f8eff32014-10-28 00:24:16 +00001550 // Splice the body of the source function into the dest function.
Rafael Espindolaef237112014-12-08 18:45:16 +00001551 Dst.getBasicBlockList().splice(Dst.end(), Src.getBasicBlockList());
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001552
Rafael Espindola9f8eff32014-10-28 00:24:16 +00001553 // At this point, all of the instructions and values of the function are now
1554 // copied over. The only problem is that they are still referencing values in
1555 // the Source function as operands. Loop through all of the operands of the
1556 // functions and patch them up to point to the local versions.
Rafael Espindolaef237112014-12-08 18:45:16 +00001557 for (BasicBlock &BB : Dst)
Rafael Espindolaa314d1a2014-12-08 14:20:10 +00001558 for (Instruction &I : BB)
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001559 RemapInstruction(&I, ValueMap,
1560 RF_IgnoreMissingEntries | RF_MoveDistinctMDs, &TypeMap,
Rafael Espindola9f8eff32014-10-28 00:24:16 +00001561 &ValMaterializer);
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001562
Chris Lattner7391dde2004-11-16 17:12:38 +00001563 // There is no need to map the arguments anymore.
Rafael Espindola3519da82014-12-08 14:25:26 +00001564 for (Argument &Arg : Src.args())
Rafael Espindolaa314d1a2014-12-08 14:20:10 +00001565 ValueMap.erase(&Arg);
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001566
Eric Christopher97cb5652015-05-15 18:20:14 +00001567 Src.dematerialize();
Rafael Espindola40d7ebe2014-12-08 13:29:33 +00001568 return false;
Reid Spencer361e5132004-11-12 20:37:43 +00001569}
1570
Rafael Espindolaef237112014-12-08 18:45:16 +00001571void ModuleLinker::linkAliasBody(GlobalAlias &Dst, GlobalAlias &Src) {
1572 Constant *Aliasee = Src.getAliasee();
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001573 Constant *Val = MapValue(Aliasee, ValueMap, RF_MoveDistinctMDs, &TypeMap,
1574 &ValMaterializer);
Rafael Espindolaef237112014-12-08 18:45:16 +00001575 Dst.setAliasee(Val);
1576}
1577
1578bool ModuleLinker::linkGlobalValueBody(GlobalValue &Src) {
1579 Value *Dst = ValueMap[&Src];
1580 assert(Dst);
Teresa Johnson2d5fb8c2015-11-10 21:09:06 +00001581 if (const Comdat *SC = Src.getComdat()) {
1582 // To ensure that we don't generate an incomplete comdat group,
1583 // we must materialize and map in any other members that are not
1584 // yet materialized in Dst, which also ensures their definitions
1585 // are linked in. Otherwise, linkonce and other lazy linked GVs will
1586 // not be materialized if they aren't referenced.
1587 for (auto *SGV : ComdatMembers[SC]) {
Rafael Espindola19b52382015-11-27 20:28:19 +00001588 auto *DGV = cast_or_null<GlobalValue>(ValueMap[SGV]);
1589 if (DGV && !DGV->isDeclaration())
Teresa Johnson2d5fb8c2015-11-10 21:09:06 +00001590 continue;
Rafael Espindola19b52382015-11-27 20:28:19 +00001591 MapValue(SGV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
Teresa Johnson2d5fb8c2015-11-10 21:09:06 +00001592 }
1593 }
Artem Belevich020d4fb2015-09-01 17:55:55 +00001594 if (shouldInternalizeLinkedSymbols())
1595 if (auto *DGV = dyn_cast<GlobalValue>(Dst))
1596 DGV->setLinkage(GlobalValue::InternalLinkage);
Rafael Espindolaef237112014-12-08 18:45:16 +00001597 if (auto *F = dyn_cast<Function>(&Src))
1598 return linkFunctionBody(cast<Function>(*Dst), *F);
1599 if (auto *GVar = dyn_cast<GlobalVariable>(&Src)) {
1600 linkGlobalInit(cast<GlobalVariable>(*Dst), *GVar);
1601 return false;
Tanya Lattnercbb91402011-10-11 00:24:54 +00001602 }
Rafael Espindolaef237112014-12-08 18:45:16 +00001603 linkAliasBody(cast<GlobalAlias>(*Dst), cast<GlobalAlias>(Src));
1604 return false;
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001605}
Anton Korobeynikov26098882008-03-05 23:21:39 +00001606
Rafael Espindola18c89412014-10-27 02:35:46 +00001607/// Insert all of the named MDNodes in Src into the Dest module.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001608void ModuleLinker::linkNamedMDNodes() {
Bill Wendling66f02412012-02-11 11:38:06 +00001609 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
Yaron Keren3bf3f1f2015-06-15 16:20:16 +00001610 for (const NamedMDNode &NMD : SrcM->named_metadata()) {
Bill Wendling66f02412012-02-11 11:38:06 +00001611 // Don't link module flags here. Do them separately.
Yaron Keren3bf3f1f2015-06-15 16:20:16 +00001612 if (&NMD == SrcModFlags)
1613 continue;
1614 NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(NMD.getName());
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001615 // Add Src elements into Dest node.
Yaron Keren3bf3f1f2015-06-15 16:20:16 +00001616 for (const MDNode *op : NMD.operands())
Teresa Johnson83d03dd2015-11-15 14:50:14 +00001617 DestNMD->addOperand(MapMetadata(
1618 op, ValueMap, RF_MoveDistinctMDs | RF_NullMapMissingGlobalValues,
1619 &TypeMap, &ValMaterializer));
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001620 }
1621}
Bill Wendling66f02412012-02-11 11:38:06 +00001622
Rafael Espindola18c89412014-10-27 02:35:46 +00001623/// Merge the linker flags in Src into the Dest module.
Bill Wendling66f02412012-02-11 11:38:06 +00001624bool ModuleLinker::linkModuleFlagsMetadata() {
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001625 // If the source module has no module flags, we are done.
Bill Wendling66f02412012-02-11 11:38:06 +00001626 const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
1627 if (!SrcModFlags) return false;
1628
Bill Wendling66f02412012-02-11 11:38:06 +00001629 // If the destination module doesn't have module flags yet, then just copy
1630 // over the source module's flags.
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001631 NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
Bill Wendling66f02412012-02-11 11:38:06 +00001632 if (DstModFlags->getNumOperands() == 0) {
1633 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
1634 DstModFlags->addOperand(SrcModFlags->getOperand(I));
1635
1636 return false;
1637 }
1638
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001639 // First build a map of the existing module flags and requirements.
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001640 DenseMap<MDString *, std::pair<MDNode *, unsigned>> Flags;
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001641 SmallSetVector<MDNode*, 16> Requirements;
1642 for (unsigned I = 0, E = DstModFlags->getNumOperands(); I != E; ++I) {
Duncan P. N. Exon Smithde36e802014-11-11 21:30:22 +00001643 MDNode *Op = DstModFlags->getOperand(I);
Duncan P. N. Exon Smith5bf8fef2014-12-09 18:38:53 +00001644 ConstantInt *Behavior = mdconst::extract<ConstantInt>(Op->getOperand(0));
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001645 MDString *ID = cast<MDString>(Op->getOperand(1));
Bill Wendling66f02412012-02-11 11:38:06 +00001646
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001647 if (Behavior->getZExtValue() == Module::Require) {
1648 Requirements.insert(cast<MDNode>(Op->getOperand(2)));
1649 } else {
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001650 Flags[ID] = std::make_pair(Op, I);
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001651 }
Bill Wendling66f02412012-02-11 11:38:06 +00001652 }
1653
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001654 // Merge in the flags from the source module, and also collect its set of
1655 // requirements.
1656 bool HasErr = false;
1657 for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I) {
Duncan P. N. Exon Smithde36e802014-11-11 21:30:22 +00001658 MDNode *SrcOp = SrcModFlags->getOperand(I);
Duncan P. N. Exon Smith5bf8fef2014-12-09 18:38:53 +00001659 ConstantInt *SrcBehavior =
1660 mdconst::extract<ConstantInt>(SrcOp->getOperand(0));
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001661 MDString *ID = cast<MDString>(SrcOp->getOperand(1));
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001662 MDNode *DstOp;
1663 unsigned DstIndex;
1664 std::tie(DstOp, DstIndex) = Flags.lookup(ID);
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001665 unsigned SrcBehaviorValue = SrcBehavior->getZExtValue();
Bill Wendling66f02412012-02-11 11:38:06 +00001666
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001667 // If this is a requirement, add it and continue.
1668 if (SrcBehaviorValue == Module::Require) {
1669 // If the destination module does not already have this requirement, add
1670 // it.
1671 if (Requirements.insert(cast<MDNode>(SrcOp->getOperand(2)))) {
1672 DstModFlags->addOperand(SrcOp);
1673 }
1674 continue;
Bill Wendling66f02412012-02-11 11:38:06 +00001675 }
1676
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001677 // If there is no existing flag with this ID, just add it.
1678 if (!DstOp) {
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001679 Flags[ID] = std::make_pair(SrcOp, DstModFlags->getNumOperands());
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001680 DstModFlags->addOperand(SrcOp);
1681 continue;
1682 }
1683
1684 // Otherwise, perform a merge.
Duncan P. N. Exon Smith5bf8fef2014-12-09 18:38:53 +00001685 ConstantInt *DstBehavior =
1686 mdconst::extract<ConstantInt>(DstOp->getOperand(0));
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001687 unsigned DstBehaviorValue = DstBehavior->getZExtValue();
1688
1689 // If either flag has override behavior, handle it first.
1690 if (DstBehaviorValue == Module::Override) {
1691 // Diagnose inconsistent flags which both have override behavior.
1692 if (SrcBehaviorValue == Module::Override &&
1693 SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1694 HasErr |= emitError("linking module flags '" + ID->getString() +
1695 "': IDs have conflicting override values");
1696 }
1697 continue;
1698 } else if (SrcBehaviorValue == Module::Override) {
1699 // Update the destination flag to that of the source.
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001700 DstModFlags->setOperand(DstIndex, SrcOp);
1701 Flags[ID].first = SrcOp;
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001702 continue;
1703 }
1704
1705 // Diagnose inconsistent merge behavior types.
1706 if (SrcBehaviorValue != DstBehaviorValue) {
1707 HasErr |= emitError("linking module flags '" + ID->getString() +
1708 "': IDs have conflicting behaviors");
1709 continue;
1710 }
1711
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001712 auto replaceDstValue = [&](MDNode *New) {
1713 Metadata *FlagOps[] = {DstOp->getOperand(0), ID, New};
1714 MDNode *Flag = MDNode::get(DstM->getContext(), FlagOps);
1715 DstModFlags->setOperand(DstIndex, Flag);
1716 Flags[ID].first = Flag;
1717 };
1718
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001719 // Perform the merge for standard behavior types.
1720 switch (SrcBehaviorValue) {
1721 case Module::Require:
Craig Topper2a30d782014-06-18 05:05:13 +00001722 case Module::Override: llvm_unreachable("not possible");
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001723 case Module::Error: {
1724 // Emit an error if the values differ.
1725 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
1726 HasErr |= emitError("linking module flags '" + ID->getString() +
1727 "': IDs have conflicting values");
1728 }
1729 continue;
1730 }
1731 case Module::Warning: {
1732 // Emit a warning if the values differ.
1733 if (SrcOp->getOperand(2) != DstOp->getOperand(2)) {
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001734 emitWarning("linking module flags '" + ID->getString() +
1735 "': IDs have conflicting values");
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001736 }
1737 continue;
1738 }
Daniel Dunbard77d9fb2013-01-16 21:38:56 +00001739 case Module::Append: {
1740 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1741 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
Duncan P. N. Exon Smith5bf8fef2014-12-09 18:38:53 +00001742 SmallVector<Metadata *, 8> MDs;
1743 MDs.reserve(DstValue->getNumOperands() + SrcValue->getNumOperands());
Benjamin Kramer6cd780f2015-02-17 15:29:18 +00001744 MDs.append(DstValue->op_begin(), DstValue->op_end());
1745 MDs.append(SrcValue->op_begin(), SrcValue->op_end());
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001746
1747 replaceDstValue(MDNode::get(DstM->getContext(), MDs));
Daniel Dunbard77d9fb2013-01-16 21:38:56 +00001748 break;
1749 }
1750 case Module::AppendUnique: {
Duncan P. N. Exon Smith5bf8fef2014-12-09 18:38:53 +00001751 SmallSetVector<Metadata *, 16> Elts;
Daniel Dunbard77d9fb2013-01-16 21:38:56 +00001752 MDNode *DstValue = cast<MDNode>(DstOp->getOperand(2));
1753 MDNode *SrcValue = cast<MDNode>(SrcOp->getOperand(2));
Benjamin Kramer6cd780f2015-02-17 15:29:18 +00001754 Elts.insert(DstValue->op_begin(), DstValue->op_end());
1755 Elts.insert(SrcValue->op_begin(), SrcValue->op_end());
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001756
1757 replaceDstValue(MDNode::get(DstM->getContext(),
1758 makeArrayRef(Elts.begin(), Elts.end())));
Daniel Dunbard77d9fb2013-01-16 21:38:56 +00001759 break;
1760 }
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001761 }
Bill Wendling66f02412012-02-11 11:38:06 +00001762 }
1763
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001764 // Check all of the requirements.
1765 for (unsigned I = 0, E = Requirements.size(); I != E; ++I) {
1766 MDNode *Requirement = Requirements[I];
1767 MDString *Flag = cast<MDString>(Requirement->getOperand(0));
Duncan P. N. Exon Smith5bf8fef2014-12-09 18:38:53 +00001768 Metadata *ReqValue = Requirement->getOperand(1);
Bill Wendling66f02412012-02-11 11:38:06 +00001769
Duncan P. N. Exon Smithdf55d8b2015-01-07 21:32:27 +00001770 MDNode *Op = Flags[Flag].first;
Daniel Dunbar0ec72bb2013-01-16 18:39:23 +00001771 if (!Op || Op->getOperand(2) != ReqValue) {
1772 HasErr |= emitError("linking module flags '" + Flag->getString() +
1773 "': does not have the required value");
1774 continue;
Bill Wendling66f02412012-02-11 11:38:06 +00001775 }
1776 }
1777
1778 return HasErr;
1779}
Rafael Espindolaed6dc372014-05-09 14:39:25 +00001780
Akira Hatanakac43df512015-02-13 00:40:41 +00001781// This function returns true if the triples match.
1782static bool triplesMatch(const Triple &T0, const Triple &T1) {
1783 // If vendor is apple, ignore the version number.
1784 if (T0.getVendor() == Triple::Apple)
1785 return T0.getArch() == T1.getArch() &&
1786 T0.getSubArch() == T1.getSubArch() &&
1787 T0.getVendor() == T1.getVendor() &&
1788 T0.getOS() == T1.getOS();
1789
1790 return T0 == T1;
1791}
1792
1793// This function returns the merged triple.
1794static std::string mergeTriples(const Triple &SrcTriple, const Triple &DstTriple) {
1795 // If vendor is apple, pick the triple with the larger version number.
1796 if (SrcTriple.getVendor() == Triple::Apple)
1797 if (DstTriple.isOSVersionLT(SrcTriple))
1798 return SrcTriple.str();
1799
1800 return DstTriple.str();
1801}
1802
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001803bool ModuleLinker::linkIfNeeded(GlobalValue &GV) {
1804 GlobalValue *DGV = getLinkedToGlobal(&GV);
1805
1806 if (shouldLinkOnlyNeeded() && !(DGV && DGV->isDeclaration()))
1807 return false;
1808
1809 if (DGV && !GV.hasLocalLinkage()) {
1810 GlobalValue::VisibilityTypes Visibility =
1811 getMinVisibility(DGV->getVisibility(), GV.getVisibility());
1812 DGV->setVisibility(Visibility);
1813 GV.setVisibility(Visibility);
1814 }
1815
1816 if (const Comdat *SC = GV.getComdat()) {
1817 bool LinkFromSrc;
1818 Comdat::SelectionKind SK;
1819 std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
1820 if (!LinkFromSrc) {
1821 DoNotLinkFromSource.insert(&GV);
1822 return false;
1823 }
1824 }
1825
1826 if (!DGV && !shouldOverrideFromSrc() &&
1827 (GV.hasLocalLinkage() || GV.hasLinkOnceLinkage() ||
1828 GV.hasAvailableExternallyLinkage())) {
1829 return false;
1830 }
1831 MapValue(&GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
1832 return HasError;
1833}
1834
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001835bool ModuleLinker::run() {
Bill Wendling66f02412012-02-11 11:38:06 +00001836 assert(DstM && "Null destination module");
1837 assert(SrcM && "Null source module");
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001838
1839 // Inherit the target data from the source module if the destination module
1840 // doesn't have one already.
Mehdi Amini46a43552015-03-04 18:43:29 +00001841 if (DstM->getDataLayout().isDefault())
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001842 DstM->setDataLayout(SrcM->getDataLayout());
1843
Mehdi Amini46a43552015-03-04 18:43:29 +00001844 if (SrcM->getDataLayout() != DstM->getDataLayout()) {
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001845 emitWarning("Linking two modules of different data layouts: '" +
1846 SrcM->getModuleIdentifier() + "' is '" +
1847 SrcM->getDataLayoutStr() + "' whereas '" +
1848 DstM->getModuleIdentifier() + "' is '" +
1849 DstM->getDataLayoutStr() + "'\n");
Eli Benderskye17f3702014-02-06 18:01:56 +00001850 }
Akira Hatanakac43df512015-02-13 00:40:41 +00001851
1852 // Copy the target triple from the source to dest if the dest's is empty.
1853 if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
1854 DstM->setTargetTriple(SrcM->getTargetTriple());
1855
1856 Triple SrcTriple(SrcM->getTargetTriple()), DstTriple(DstM->getTargetTriple());
1857
1858 if (!SrcM->getTargetTriple().empty() && !triplesMatch(SrcTriple, DstTriple))
Rafael Espindolad12b4a32014-10-25 04:06:10 +00001859 emitWarning("Linking two modules of different target triples: " +
1860 SrcM->getModuleIdentifier() + "' is '" +
1861 SrcM->getTargetTriple() + "' whereas '" +
1862 DstM->getModuleIdentifier() + "' is '" +
1863 DstM->getTargetTriple() + "'\n");
Akira Hatanakac43df512015-02-13 00:40:41 +00001864
1865 DstM->setTargetTriple(mergeTriples(SrcTriple, DstTriple));
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001866
1867 // Append the module inline asm string.
1868 if (!SrcM->getModuleInlineAsm().empty()) {
1869 if (DstM->getModuleInlineAsm().empty())
1870 DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
1871 else
1872 DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
1873 SrcM->getModuleInlineAsm());
1874 }
1875
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001876 // Loop over all of the linked values to compute type mappings.
1877 computeTypeMapping();
1878
David Majnemerdad0a642014-06-27 18:19:56 +00001879 ComdatsChosen.clear();
David Blaikie5106ce72014-11-19 05:49:42 +00001880 for (const auto &SMEC : SrcM->getComdatSymbolTable()) {
David Majnemerdad0a642014-06-27 18:19:56 +00001881 const Comdat &C = SMEC.getValue();
1882 if (ComdatsChosen.count(&C))
1883 continue;
1884 Comdat::SelectionKind SK;
1885 bool LinkFromSrc;
1886 if (getComdatResult(&C, SK, LinkFromSrc))
1887 return true;
1888 ComdatsChosen[&C] = std::make_pair(SK, LinkFromSrc);
1889 }
1890
Duncan P. N. Exon Smith09d84ad2014-08-12 16:46:37 +00001891 // Upgrade mismatched global arrays.
1892 upgradeMismatchedGlobals();
1893
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001894 for (GlobalVariable &GV : SrcM->globals())
1895 if (const Comdat *SC = GV.getComdat())
1896 ComdatMembers[SC].push_back(&GV);
1897
1898 for (Function &SF : *SrcM)
1899 if (const Comdat *SC = SF.getComdat())
1900 ComdatMembers[SC].push_back(&SF);
1901
1902 for (GlobalAlias &GA : SrcM->aliases())
1903 if (const Comdat *SC = GA.getComdat())
1904 ComdatMembers[SC].push_back(&GA);
1905
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001906 // Insert all of the globals in src into the DstM module... without linking
1907 // initializers (which could refer to functions not yet mapped over).
Yaron Keren3bf3f1f2015-06-15 16:20:16 +00001908 for (GlobalVariable &GV : SrcM->globals())
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001909 if (linkIfNeeded(GV))
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001910 return true;
1911
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001912 for (Function &SF : *SrcM)
1913 if (linkIfNeeded(SF))
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001914 return true;
1915
Yaron Keren3bf3f1f2015-06-15 16:20:16 +00001916 for (GlobalAlias &GA : SrcM->aliases())
Rafael Espindolabaa3bf82015-12-01 15:19:48 +00001917 if (linkIfNeeded(GA))
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00001918 return true;
1919
Rafael Espindolabeadd562014-12-08 18:05:48 +00001920 for (const auto &Entry : DstM->getComdatSymbolTable()) {
1921 const Comdat &C = Entry.getValue();
1922 if (C.getSelectionKind() == Comdat::Any)
1923 continue;
1924 const GlobalValue *GV = SrcM->getNamedValue(C.getName());
Peter Collingbourneea45d832015-06-22 21:46:51 +00001925 if (GV)
Duncan P. N. Exon Smith4fb46cb2015-08-03 17:09:38 +00001926 MapValue(GV, ValueMap, RF_MoveDistinctMDs, &TypeMap, &ValMaterializer);
Rafael Espindolabeadd562014-12-08 18:05:48 +00001927 }
1928
Teresa Johnson10632932015-11-06 17:50:53 +00001929 // Note that we are done linking global value bodies. This prevents
1930 // metadata linking from creating new references.
1931 DoneLinkingBodies = true;
1932
Teresa Johnson189b2522015-11-06 17:50:48 +00001933 // Remap all of the named MDNodes in Src into the DstM module. We do this
1934 // after linking GlobalValues so that MDNodes that reference GlobalValues
1935 // are properly remapped.
1936 linkNamedMDNodes();
1937
1938 // Merge the module flags into the DstM module.
1939 if (linkModuleFlagsMetadata())
1940 return true;
1941
Anton Korobeynikov26098882008-03-05 23:21:39 +00001942 return false;
1943}
Reid Spencer361e5132004-11-12 20:37:43 +00001944
Rafael Espindola31ad4682014-12-03 22:36:37 +00001945Linker::StructTypeKeyInfo::KeyTy::KeyTy(ArrayRef<Type *> E, bool P)
1946 : ETypes(E), IsPacked(P) {}
1947
1948Linker::StructTypeKeyInfo::KeyTy::KeyTy(const StructType *ST)
1949 : ETypes(ST->elements()), IsPacked(ST->isPacked()) {}
1950
1951bool Linker::StructTypeKeyInfo::KeyTy::operator==(const KeyTy &That) const {
1952 if (IsPacked != That.IsPacked)
1953 return false;
1954 if (ETypes != That.ETypes)
1955 return false;
1956 return true;
1957}
1958
1959bool Linker::StructTypeKeyInfo::KeyTy::operator!=(const KeyTy &That) const {
1960 return !this->operator==(That);
1961}
1962
1963StructType *Linker::StructTypeKeyInfo::getEmptyKey() {
1964 return DenseMapInfo<StructType *>::getEmptyKey();
1965}
1966
1967StructType *Linker::StructTypeKeyInfo::getTombstoneKey() {
1968 return DenseMapInfo<StructType *>::getTombstoneKey();
1969}
1970
1971unsigned Linker::StructTypeKeyInfo::getHashValue(const KeyTy &Key) {
1972 return hash_combine(hash_combine_range(Key.ETypes.begin(), Key.ETypes.end()),
1973 Key.IsPacked);
1974}
1975
1976unsigned Linker::StructTypeKeyInfo::getHashValue(const StructType *ST) {
1977 return getHashValue(KeyTy(ST));
1978}
1979
1980bool Linker::StructTypeKeyInfo::isEqual(const KeyTy &LHS,
1981 const StructType *RHS) {
1982 if (RHS == getEmptyKey() || RHS == getTombstoneKey())
1983 return false;
1984 return LHS == KeyTy(RHS);
1985}
1986
1987bool Linker::StructTypeKeyInfo::isEqual(const StructType *LHS,
1988 const StructType *RHS) {
1989 if (RHS == getEmptyKey())
1990 return LHS == getEmptyKey();
1991
1992 if (RHS == getTombstoneKey())
1993 return LHS == getTombstoneKey();
1994
1995 return KeyTy(LHS) == KeyTy(RHS);
1996}
1997
1998void Linker::IdentifiedStructTypeSet::addNonOpaque(StructType *Ty) {
1999 assert(!Ty->isOpaque());
Benjamin Kramer3280a5d2014-12-06 19:22:54 +00002000 NonOpaqueStructTypes.insert(Ty);
Rafael Espindola31ad4682014-12-03 22:36:37 +00002001}
2002
Rafael Espindolaa5b9e1c2015-03-06 00:50:21 +00002003void Linker::IdentifiedStructTypeSet::switchToNonOpaque(StructType *Ty) {
2004 assert(!Ty->isOpaque());
2005 NonOpaqueStructTypes.insert(Ty);
2006 bool Removed = OpaqueStructTypes.erase(Ty);
2007 (void)Removed;
2008 assert(Removed);
2009}
2010
Rafael Espindola31ad4682014-12-03 22:36:37 +00002011void Linker::IdentifiedStructTypeSet::addOpaque(StructType *Ty) {
2012 assert(Ty->isOpaque());
2013 OpaqueStructTypes.insert(Ty);
2014}
2015
2016StructType *
2017Linker::IdentifiedStructTypeSet::findNonOpaque(ArrayRef<Type *> ETypes,
2018 bool IsPacked) {
2019 Linker::StructTypeKeyInfo::KeyTy Key(ETypes, IsPacked);
2020 auto I = NonOpaqueStructTypes.find_as(Key);
2021 if (I == NonOpaqueStructTypes.end())
2022 return nullptr;
Benjamin Kramer3280a5d2014-12-06 19:22:54 +00002023 return *I;
Rafael Espindola31ad4682014-12-03 22:36:37 +00002024}
2025
2026bool Linker::IdentifiedStructTypeSet::hasType(StructType *Ty) {
2027 if (Ty->isOpaque())
2028 return OpaqueStructTypes.count(Ty);
2029 auto I = NonOpaqueStructTypes.find(Ty);
2030 if (I == NonOpaqueStructTypes.end())
2031 return false;
Benjamin Kramer3280a5d2014-12-06 19:22:54 +00002032 return *I == Ty;
Rafael Espindola31ad4682014-12-03 22:36:37 +00002033}
2034
Rafael Espindola5cb9c822014-11-17 20:51:01 +00002035void Linker::init(Module *M, DiagnosticHandlerFunction DiagnosticHandler) {
2036 this->Composite = M;
2037 this->DiagnosticHandler = DiagnosticHandler;
Rafael Espindolaa4e85e32014-12-01 16:32:20 +00002038
2039 TypeFinder StructTypes;
2040 StructTypes.run(*M, true);
Rafael Espindola31ad4682014-12-03 22:36:37 +00002041 for (StructType *Ty : StructTypes) {
2042 if (Ty->isOpaque())
2043 IdentifiedStructTypes.addOpaque(Ty);
2044 else
2045 IdentifiedStructTypes.addNonOpaque(Ty);
2046 }
Rafael Espindolaaa9918a2013-05-04 05:05:18 +00002047}
Rafael Espindola3df61b72013-05-04 03:48:37 +00002048
Rafael Espindola5cb9c822014-11-17 20:51:01 +00002049Linker::Linker(Module *M, DiagnosticHandlerFunction DiagnosticHandler) {
2050 init(M, DiagnosticHandler);
2051}
2052
2053Linker::Linker(Module *M) {
2054 init(M, [this](const DiagnosticInfo &DI) {
2055 Composite->getContext().diagnose(DI);
2056 });
2057}
2058
Bill Wendling91e6f6e2013-10-16 08:59:57 +00002059void Linker::deleteModule() {
2060 delete Composite;
Craig Topper2617dcc2014-04-15 06:32:26 +00002061 Composite = nullptr;
Bill Wendling91e6f6e2013-10-16 08:59:57 +00002062}
2063
Mehdi Amini8220e8a2015-11-23 01:59:16 +00002064bool Linker::linkInModule(Module *Src, unsigned Flags,
2065 const FunctionInfoIndex *Index,
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00002066 Function *FuncToImport) {
Rafael Espindolaa4e85e32014-12-01 16:32:20 +00002067 ModuleLinker TheLinker(Composite, IdentifiedStructTypes, Src,
Teresa Johnsonc7ed52f2015-11-03 00:14:15 +00002068 DiagnosticHandler, Flags, Index, FuncToImport);
Manman Rendab999d2015-01-20 19:24:59 +00002069 bool RetCode = TheLinker.run();
2070 Composite->dropTriviallyDeadConstantArrays();
2071 return RetCode;
Rafael Espindola3df61b72013-05-04 03:48:37 +00002072}
2073
Chris Lattnerb1ed91f2011-07-09 17:41:24 +00002074//===----------------------------------------------------------------------===//
2075// LinkModules entrypoint.
2076//===----------------------------------------------------------------------===//
2077
Rafael Espindola18c89412014-10-27 02:35:46 +00002078/// This function links two modules together, with the resulting Dest module
2079/// modified to be the composite of the two input modules. If an error occurs,
2080/// true is returned and ErrorMsg (if not null) is set to indicate the problem.
2081/// Upon failure, the Dest module could be in a modified state, and shouldn't be
2082/// relied on to be consistent.
Rafael Espindola9f8eff32014-10-28 00:24:16 +00002083bool Linker::LinkModules(Module *Dest, Module *Src,
Artem Belevich020d4fb2015-09-01 17:55:55 +00002084 DiagnosticHandlerFunction DiagnosticHandler,
2085 unsigned Flags) {
Rafael Espindola4160f5d2014-10-27 23:02:10 +00002086 Linker L(Dest, DiagnosticHandler);
Artem Belevich020d4fb2015-09-01 17:55:55 +00002087 return L.linkInModule(Src, Flags);
Rafael Espindola4160f5d2014-10-27 23:02:10 +00002088}
2089
Artem Belevich020d4fb2015-09-01 17:55:55 +00002090bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Flags) {
Rafael Espindola287f18b2013-05-04 04:08:02 +00002091 Linker L(Dest);
Artem Belevich020d4fb2015-09-01 17:55:55 +00002092 return L.linkInModule(Src, Flags);
Reid Spencer361e5132004-11-12 20:37:43 +00002093}
Bill Wendlinga3aeb982012-05-09 08:55:40 +00002094
2095//===----------------------------------------------------------------------===//
2096// C API.
2097//===----------------------------------------------------------------------===//
2098
2099LLVMBool LLVMLinkModules(LLVMModuleRef Dest, LLVMModuleRef Src,
Juergen Ributzkaa57d5882015-03-02 18:59:38 +00002100 LLVMLinkerMode Unused, char **OutMessages) {
Rafael Espindola98ab63c2014-10-25 04:31:08 +00002101 Module *D = unwrap(Dest);
Rafael Espindola98ab63c2014-10-25 04:31:08 +00002102 std::string Message;
Rafael Espindola4160f5d2014-10-27 23:02:10 +00002103 raw_string_ostream Stream(Message);
2104 DiagnosticPrinterRawOStream DP(Stream);
2105
2106 LLVMBool Result = Linker::LinkModules(
Rafael Espindola9f8eff32014-10-28 00:24:16 +00002107 D, unwrap(Src), [&](const DiagnosticInfo &DI) { DI.print(DP); });
Rafael Espindola98ab63c2014-10-25 04:31:08 +00002108
Eli Benderskyff715e22015-06-12 23:26:42 +00002109 if (OutMessages && Result) {
2110 Stream.flush();
Rafael Espindola98ab63c2014-10-25 04:31:08 +00002111 *OutMessages = strdup(Message.c_str());
Eli Benderskyff715e22015-06-12 23:26:42 +00002112 }
Bill Wendlinga3aeb982012-05-09 08:55:40 +00002113 return Result;
2114}