IR: Add COMDATs to the IR
This new IR facility allows us to represent the object-file semantic of
a COMDAT group.
COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.
This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.
Differential Revision: http://reviews.llvm.org/D4178
llvm-svn: 211920
diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index 1334825..1e5bcdd 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -209,6 +209,7 @@
return LexToken();
case '+': return LexPositive();
case '@': return LexAt();
+ case '$': return LexDollar();
case '%': return LexPercent();
case '"': return LexQuote();
case '.':
@@ -222,13 +223,6 @@
return lltok::dotdotdot;
}
return lltok::Error;
- case '$':
- if (const char *Ptr = isLabelTail(CurPtr)) {
- CurPtr = Ptr;
- StrVal.assign(TokStart, CurPtr-1);
- return lltok::LabelStr;
- }
- return lltok::Error;
case ';':
SkipLineComment();
return LexToken();
@@ -307,6 +301,43 @@
return lltok::Error;
}
+lltok::Kind LLLexer::LexDollar() {
+ if (const char *Ptr = isLabelTail(TokStart)) {
+ CurPtr = Ptr;
+ StrVal.assign(TokStart, CurPtr - 1);
+ return lltok::LabelStr;
+ }
+
+ // Handle DollarStringConstant: $\"[^\"]*\"
+ if (CurPtr[0] == '"') {
+ ++CurPtr;
+
+ while (1) {
+ int CurChar = getNextChar();
+
+ if (CurChar == EOF) {
+ Error("end of file in COMDAT variable name");
+ return lltok::Error;
+ }
+ if (CurChar == '"') {
+ StrVal.assign(TokStart + 2, CurPtr - 1);
+ UnEscapeLexed(StrVal);
+ if (StringRef(StrVal).find_first_of(0) != StringRef::npos) {
+ Error("Null bytes are not allowed in names");
+ return lltok::Error;
+ }
+ return lltok::ComdatVar;
+ }
+ }
+ }
+
+ // Handle ComdatVarName: $[-a-zA-Z$._][-a-zA-Z$._0-9]*
+ if (ReadVarName())
+ return lltok::ComdatVar;
+
+ return lltok::Error;
+}
+
/// ReadString - Read a string until the closing quote.
lltok::Kind LLLexer::ReadString(lltok::Kind kind) {
const char *Start = CurPtr;
@@ -618,6 +649,15 @@
KEYWORD(type);
KEYWORD(opaque);
+ KEYWORD(comdat);
+
+ // Comdat types
+ KEYWORD(any);
+ KEYWORD(exactmatch);
+ KEYWORD(largest);
+ KEYWORD(noduplicates);
+ KEYWORD(samesize);
+
KEYWORD(eq); KEYWORD(ne); KEYWORD(slt); KEYWORD(sgt); KEYWORD(sle);
KEYWORD(sge); KEYWORD(ult); KEYWORD(ugt); KEYWORD(ule); KEYWORD(uge);
KEYWORD(oeq); KEYWORD(one); KEYWORD(olt); KEYWORD(ogt); KEYWORD(ole);
diff --git a/llvm/lib/AsmParser/LLLexer.h b/llvm/lib/AsmParser/LLLexer.h
index ad11d49..d42de57 100644
--- a/llvm/lib/AsmParser/LLLexer.h
+++ b/llvm/lib/AsmParser/LLLexer.h
@@ -81,6 +81,7 @@
lltok::Kind LexDigitOrNegative();
lltok::Kind LexPositive();
lltok::Kind LexAt();
+ lltok::Kind LexDollar();
lltok::Kind LexExclaim();
lltok::Kind LexPercent();
lltok::Kind LexQuote();
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index f444206..be55ac6 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -163,6 +163,11 @@
return Error(I->second.second,
"use of undefined type named '" + I->getKey() + "'");
+ if (!ForwardRefComdats.empty())
+ return Error(ForwardRefComdats.begin()->second,
+ "use of undefined comdat '$" +
+ ForwardRefComdats.begin()->first + "'");
+
if (!ForwardRefVals.empty())
return Error(ForwardRefVals.begin()->second.second,
"use of undefined value '@" + ForwardRefVals.begin()->first +
@@ -238,6 +243,7 @@
case lltok::LocalVar: if (ParseNamedType()) return true; break;
case lltok::GlobalID: if (ParseUnnamedGlobal()) return true; break;
case lltok::GlobalVar: if (ParseNamedGlobal()) return true; break;
+ case lltok::ComdatVar: if (parseComdat()) return true; break;
case lltok::exclaim: if (ParseStandaloneMetadata()) return true; break;
case lltok::MetadataVar:if (ParseNamedMetadata()) return true; break;
@@ -513,6 +519,56 @@
UnnamedAddr);
}
+bool LLParser::parseComdat() {
+ assert(Lex.getKind() == lltok::ComdatVar);
+ std::string Name = Lex.getStrVal();
+ LocTy NameLoc = Lex.getLoc();
+ Lex.Lex();
+
+ if (ParseToken(lltok::equal, "expected '=' here"))
+ return true;
+
+ if (ParseToken(lltok::kw_comdat, "expected comdat keyword"))
+ return TokError("expected comdat type");
+
+ Comdat::SelectionKind SK;
+ switch (Lex.getKind()) {
+ default:
+ return TokError("unknown selection kind");
+ case lltok::kw_any:
+ SK = Comdat::Any;
+ break;
+ case lltok::kw_exactmatch:
+ SK = Comdat::ExactMatch;
+ break;
+ case lltok::kw_largest:
+ SK = Comdat::Largest;
+ break;
+ case lltok::kw_noduplicates:
+ SK = Comdat::NoDuplicates;
+ break;
+ case lltok::kw_samesize:
+ SK = Comdat::SameSize;
+ break;
+ }
+ Lex.Lex();
+
+ // See if the comdat was forward referenced, if so, use the comdat.
+ Module::ComdatSymTabType &ComdatSymTab = M->getComdatSymbolTable();
+ Module::ComdatSymTabType::iterator I = ComdatSymTab.find(Name);
+ if (I != ComdatSymTab.end() && !ForwardRefComdats.erase(Name))
+ return Error(NameLoc, "redefinition of comdat '$" + Name + "'");
+
+ Comdat *C;
+ if (I != ComdatSymTab.end())
+ C = &I->second;
+ else
+ C = M->getOrInsertComdat(Name);
+ C->setSelectionKind(SK);
+
+ return false;
+}
+
// MDString:
// ::= '!' STRINGCONSTANT
bool LLParser::ParseMDString(MDString *&Result) {
@@ -838,7 +894,13 @@
if (ParseOptionalAlignment(Alignment)) return true;
GV->setAlignment(Alignment);
} else {
- TokError("unknown global variable property!");
+ Comdat *C;
+ if (parseOptionalComdat(C))
+ return true;
+ if (C)
+ GV->setComdat(C);
+ else
+ return TokError("unknown global variable property!");
}
}
@@ -1097,6 +1159,24 @@
//===----------------------------------------------------------------------===//
+// Comdat Reference/Resolution Routines.
+//===----------------------------------------------------------------------===//
+
+Comdat *LLParser::getComdat(const std::string &Name, LocTy Loc) {
+ // Look this name up in the comdat symbol table.
+ Module::ComdatSymTabType &ComdatSymTab = M->getComdatSymbolTable();
+ Module::ComdatSymTabType::iterator I = ComdatSymTab.find(Name);
+ if (I != ComdatSymTab.end())
+ return &I->second;
+
+ // Otherwise, create a new forward reference for this value and remember it.
+ Comdat *C = M->getOrInsertComdat(Name);
+ ForwardRefComdats[Name] = Loc;
+ return C;
+}
+
+
+//===----------------------------------------------------------------------===//
// Helper Routines.
//===----------------------------------------------------------------------===//
@@ -2790,6 +2870,19 @@
ParseGlobalValue(Ty, V);
}
+bool LLParser::parseOptionalComdat(Comdat *&C) {
+ C = nullptr;
+ if (!EatIfPresent(lltok::kw_comdat))
+ return false;
+ if (Lex.getKind() != lltok::ComdatVar)
+ return TokError("expected comdat variable");
+ LocTy Loc = Lex.getLoc();
+ StringRef Name = Lex.getStrVal();
+ C = getComdat(Name, Loc);
+ Lex.Lex();
+ return false;
+}
+
/// ParseGlobalValueVector
/// ::= /*empty*/
/// ::= TypeAndValue (',' TypeAndValue)*
@@ -3090,6 +3183,7 @@
bool UnnamedAddr;
LocTy UnnamedAddrLoc;
Constant *Prefix = nullptr;
+ Comdat *C;
if (ParseArgumentList(ArgList, isVarArg) ||
ParseOptionalToken(lltok::kw_unnamed_addr, UnnamedAddr,
@@ -3098,6 +3192,7 @@
BuiltinLoc) ||
(EatIfPresent(lltok::kw_section) &&
ParseStringConstant(Section)) ||
+ parseOptionalComdat(C) ||
ParseOptionalAlignment(Alignment) ||
(EatIfPresent(lltok::kw_gc) &&
ParseStringConstant(GC)) ||
@@ -3200,6 +3295,7 @@
Fn->setUnnamedAddr(UnnamedAddr);
Fn->setAlignment(Alignment);
Fn->setSection(Section);
+ Fn->setComdat(C);
if (!GC.empty()) Fn->setGC(GC.c_str());
Fn->setPrefixData(Prefix);
ForwardRefAttrGroups[Fn] = FwdRefAttrGrps;
diff --git a/llvm/lib/AsmParser/LLParser.h b/llvm/lib/AsmParser/LLParser.h
index f7d69d2..2efb260 100644
--- a/llvm/lib/AsmParser/LLParser.h
+++ b/llvm/lib/AsmParser/LLParser.h
@@ -34,6 +34,7 @@
class Instruction;
class Constant;
class GlobalValue;
+ class Comdat;
class MDString;
class MDNode;
class StructType;
@@ -122,6 +123,9 @@
std::map<unsigned, std::pair<GlobalValue*, LocTy> > ForwardRefValIDs;
std::vector<GlobalValue*> NumberedVals;
+ // Comdat forward reference information.
+ std::map<std::string, LocTy> ForwardRefComdats;
+
// References to blockaddress. The key is the function ValID, the value is
// a list of references to blocks in that function.
std::map<ValID, std::vector<std::pair<ValID, GlobalValue*> > >
@@ -154,6 +158,10 @@
GlobalValue *GetGlobalVal(const std::string &N, Type *Ty, LocTy Loc);
GlobalValue *GetGlobalVal(unsigned ID, Type *Ty, LocTy Loc);
+ /// Get a Comdat with the specified name, creating a forward reference
+ /// record if needed.
+ Comdat *getComdat(const std::string &N, LocTy Loc);
+
// Helper Routines.
bool ParseToken(lltok::Kind T, const char *ErrMsg);
bool EatIfPresent(lltok::Kind T) {
@@ -247,6 +255,7 @@
bool ParseAlias(const std::string &Name, LocTy Loc, unsigned Visibility,
unsigned DLLStorageClass,
GlobalVariable::ThreadLocalMode TLM, bool UnnamedAddr);
+ bool parseComdat();
bool ParseStandaloneMetadata();
bool ParseNamedMetadata();
bool ParseMDString(MDString *&Result);
@@ -358,6 +367,7 @@
bool ParseGlobalValue(Type *Ty, Constant *&V);
bool ParseGlobalTypeAndValue(Constant *&V);
bool ParseGlobalValueVector(SmallVectorImpl<Constant*> &Elts);
+ bool parseOptionalComdat(Comdat *&C);
bool ParseMetadataListValue(ValID &ID, PerFunctionState *PFS);
bool ParseMetadataValue(ValID &ID, PerFunctionState *PFS);
bool ParseMDNodeVector(SmallVectorImpl<Value*> &, PerFunctionState *PFS);
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index af8b0da..534d824 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -142,6 +142,15 @@
kw_type,
kw_opaque,
+ kw_comdat,
+
+ // Comdat types
+ kw_any,
+ kw_exactmatch,
+ kw_largest,
+ kw_noduplicates,
+ kw_samesize,
+
kw_eq, kw_ne, kw_slt, kw_sgt, kw_sle, kw_sge, kw_ult, kw_ugt, kw_ule,
kw_uge, kw_oeq, kw_one, kw_olt, kw_ogt, kw_ole, kw_oge, kw_ord, kw_uno,
kw_ueq, kw_une,
@@ -180,6 +189,7 @@
// String valued tokens (StrVal).
LabelStr, // foo:
GlobalVar, // @foo @"foo"
+ ComdatVar, // $foo
LocalVar, // %foo %"foo"
MetadataVar, // !foo
StringConstant, // "foo"
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 4bbecfd..524a1a8 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -43,6 +43,7 @@
std::vector<Type*>().swap(TypeList);
ValueList.clear();
MDValueList.clear();
+ std::vector<Comdat *>().swap(ComdatList);
std::vector<AttributeSet>().swap(MAttributes);
std::vector<BasicBlock*>().swap(FunctionBBs);
@@ -203,6 +204,22 @@
}
}
+static Comdat::SelectionKind getDecodedComdatSelectionKind(unsigned Val) {
+ switch (Val) {
+ default: // Map unknown selection kinds to any.
+ case bitc::COMDAT_SELECTION_KIND_ANY:
+ return Comdat::Any;
+ case bitc::COMDAT_SELECTION_KIND_EXACT_MATCH:
+ return Comdat::ExactMatch;
+ case bitc::COMDAT_SELECTION_KIND_LARGEST:
+ return Comdat::Largest;
+ case bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES:
+ return Comdat::NoDuplicates;
+ case bitc::COMDAT_SELECTION_KIND_SAME_SIZE:
+ return Comdat::SameSize;
+ }
+}
+
static void UpgradeDLLImportExportLinkage(llvm::GlobalValue *GV, unsigned Val) {
switch (Val) {
case 5: GV->setDLLStorageClass(GlobalValue::DLLImportStorageClass); break;
@@ -1838,6 +1855,20 @@
GCTable.push_back(S);
break;
}
+ case bitc::MODULE_CODE_COMDAT: { // COMDAT: [selection_kind, name]
+ if (Record.size() < 2)
+ return Error(InvalidRecord);
+ Comdat::SelectionKind SK = getDecodedComdatSelectionKind(Record[0]);
+ unsigned ComdatNameSize = Record[1];
+ std::string ComdatName;
+ ComdatName.reserve(ComdatNameSize);
+ for (unsigned i = 0; i != ComdatNameSize; ++i)
+ ComdatName += (char)Record[2 + i];
+ Comdat *C = TheModule->getOrInsertComdat(ComdatName);
+ C->setSelectionKind(SK);
+ ComdatList.push_back(C);
+ break;
+ }
// GLOBALVAR: [pointer type, isconst, initid,
// linkage, alignment, section, visibility, threadlocal,
// unnamed_addr, dllstorageclass]
@@ -1898,6 +1929,12 @@
// Remember which value to use for the global initializer.
if (unsigned InitID = Record[2])
GlobalInits.push_back(std::make_pair(NewGV, InitID-1));
+
+ if (Record.size() > 11)
+ if (unsigned ComdatID = Record[11]) {
+ assert(ComdatID <= ComdatList.size());
+ NewGV->setComdat(ComdatList[ComdatID - 1]);
+ }
break;
}
// FUNCTION: [type, callingconv, isproto, linkage, paramattr,
@@ -1951,6 +1988,12 @@
else
UpgradeDLLImportExportLinkage(Func, Record[3]);
+ if (Record.size() > 12)
+ if (unsigned ComdatID = Record[12]) {
+ assert(ComdatID <= ComdatList.size());
+ Func->setComdat(ComdatList[ComdatID - 1]);
+ }
+
ValueList.push_back(Func);
// If this is a function with a body, remember the prototype we are
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.h b/llvm/lib/Bitcode/Reader/BitcodeReader.h
index 7d79726..0771bcb 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.h
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.h
@@ -26,6 +26,7 @@
#include <vector>
namespace llvm {
+ class Comdat;
class MemoryBuffer;
class LLVMContext;
@@ -135,6 +136,7 @@
std::vector<Type*> TypeList;
BitcodeReaderValueList ValueList;
BitcodeReaderMDValueList MDValueList;
+ std::vector<Comdat *> ComdatList;
SmallVector<Instruction *, 64> InstructionList;
SmallVector<SmallVector<uint64_t, 64>, 64> UseListRecords;
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 3ba7358..dd9282a 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -524,6 +524,35 @@
llvm_unreachable("Invalid TLS model");
}
+static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
+ switch (C.getSelectionKind()) {
+ case Comdat::Any:
+ return bitc::COMDAT_SELECTION_KIND_ANY;
+ case Comdat::ExactMatch:
+ return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
+ case Comdat::Largest:
+ return bitc::COMDAT_SELECTION_KIND_LARGEST;
+ case Comdat::NoDuplicates:
+ return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
+ case Comdat::SameSize:
+ return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
+ }
+ llvm_unreachable("Invalid selection kind");
+}
+
+static void writeComdats(const ValueEnumerator &VE, BitstreamWriter &Stream) {
+ SmallVector<uint8_t, 64> Vals;
+ for (const Comdat *C : VE.getComdats()) {
+ // COMDAT: [selection_kind, name]
+ Vals.push_back(getEncodedComdatSelectionKind(*C));
+ Vals.push_back(C->getName().size());
+ for (char Chr : C->getName())
+ Vals.push_back((unsigned char)Chr);
+ Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
+ Vals.clear();
+ }
+}
+
// Emit top-level description of module, including target triple, inline asm,
// descriptors for global variables, and function prototype info.
static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
@@ -625,12 +654,14 @@
if (GV.isThreadLocal() ||
GV.getVisibility() != GlobalValue::DefaultVisibility ||
GV.hasUnnamedAddr() || GV.isExternallyInitialized() ||
- GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass) {
+ GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
+ GV.hasComdat()) {
Vals.push_back(getEncodedVisibility(GV));
Vals.push_back(getEncodedThreadLocalMode(GV));
Vals.push_back(GV.hasUnnamedAddr());
Vals.push_back(GV.isExternallyInitialized());
Vals.push_back(getEncodedDLLStorageClass(GV));
+ Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
} else {
AbbrevToUse = SimpleGVarAbbrev;
}
@@ -656,6 +687,7 @@
Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
: 0);
Vals.push_back(getEncodedDLLStorageClass(F));
+ Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
unsigned AbbrevToUse = 0;
Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
@@ -1915,6 +1947,8 @@
// Emit information describing all of the types in the module.
WriteTypeTable(VE, Stream);
+ writeComdats(VE, Stream);
+
// Emit top-level description of module, including target triple, inline asm,
// descriptors for global variables, and function prototype info.
WriteModuleInfo(M, VE, Stream);
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
index befe15bb..15f8034 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -117,6 +117,12 @@
return I->second;
}
+unsigned ValueEnumerator::getComdatID(const Comdat *C) const {
+ unsigned ComdatID = Comdats.idFor(C);
+ assert(ComdatID && "Comdat not found!");
+ return ComdatID;
+}
+
void ValueEnumerator::setInstructionID(const Instruction *I) {
InstructionMap[I] = InstructionCount++;
}
@@ -307,6 +313,10 @@
return;
}
+ if (auto *GO = dyn_cast<GlobalObject>(V))
+ if (const Comdat *C = GO->getComdat())
+ Comdats.insert(C);
+
// Enumerate the type of this value.
EnumerateType(V->getType());
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.h b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
index d1ca15f..1c9f38e 100644
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
@@ -16,6 +16,7 @@
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/UniqueVector.h"
#include "llvm/IR/Attributes.h"
#include <vector>
@@ -25,6 +26,7 @@
class Value;
class Instruction;
class BasicBlock;
+class Comdat;
class Function;
class Module;
class MDNode;
@@ -48,6 +50,10 @@
typedef DenseMap<const Value*, unsigned> ValueMapType;
ValueMapType ValueMap;
ValueList Values;
+
+ typedef UniqueVector<const Comdat *> ComdatSetType;
+ ComdatSetType Comdats;
+
ValueList MDValues;
SmallVector<const MDNode *, 8> FunctionLocalMDs;
ValueMapType MDValueMap;
@@ -139,6 +145,9 @@
return AttributeGroups;
}
+ const ComdatSetType &getComdats() const { return Comdats; }
+ unsigned getComdatID(const Comdat *C) const;
+
/// getGlobalBasicBlockID - This returns the function-specific ID for the
/// specified basic block. This is relatively expensive information, so it
/// should only be used by rare constructs such as address-of-label.
diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 9cef50e..42a0e92 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -192,6 +192,18 @@
return Flags;
}
+static const Comdat *getELFComdat(const GlobalValue *GV) {
+ const Comdat *C = GV->getComdat();
+ if (!C)
+ return nullptr;
+
+ if (C->getSelectionKind() != Comdat::Any)
+ report_fatal_error("ELF COMDATs only support SelectionKind::Any, '" +
+ C->getName() + "' cannot be lowered.");
+
+ return C;
+}
+
const MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const {
@@ -200,9 +212,15 @@
// Infer section flags from the section name if we can.
Kind = getELFKindForNamedSection(SectionName, Kind);
+ StringRef Group = "";
+ unsigned Flags = getELFSectionFlags(Kind);
+ if (const Comdat *C = getELFComdat(GV)) {
+ Group = C->getName();
+ Flags |= ELF::SHF_GROUP;
+ }
return getContext().getELFSection(SectionName,
- getELFSectionType(SectionName, Kind),
- getELFSectionFlags(Kind), Kind);
+ getELFSectionType(SectionName, Kind), Flags,
+ Kind, /*EntrySize=*/0, Group);
}
/// getSectionPrefixForGlobal - Return the section prefix name used by options
@@ -224,7 +242,6 @@
return ".data.rel.ro.";
}
-
const MCSection *TargetLoweringObjectFileELF::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler &Mang, const TargetMachine &TM) const {
@@ -238,7 +255,7 @@
// If this global is linkonce/weak and the target handles this by emitting it
// into a 'uniqued' section name, create and return the section now.
- if ((GV->isWeakForLinker() || EmitUniquedSection) &&
+ if ((GV->isWeakForLinker() || EmitUniquedSection || GV->hasComdat()) &&
!Kind.isCommon()) {
StringRef Prefix = getSectionPrefixForGlobal(Kind);
@@ -247,8 +264,11 @@
StringRef Group = "";
unsigned Flags = getELFSectionFlags(Kind);
- if (GV->isWeakForLinker()) {
- Group = Name.substr(Prefix.size());
+ if (GV->isWeakForLinker() || GV->hasComdat()) {
+ if (const Comdat *C = getELFComdat(GV))
+ Group = C->getName();
+ else
+ Group = Name.substr(Prefix.size());
Flags |= ELF::SHF_GROUP;
}
@@ -482,6 +502,15 @@
Streamer.AddBlankLine();
}
+static void checkMachOComdat(const GlobalValue *GV) {
+ const Comdat *C = GV->getComdat();
+ if (!C)
+ return;
+
+ report_fatal_error("MachO doesn't support COMDATs, '" + C->getName() +
+ "' cannot be lowered.");
+}
+
const MCSection *TargetLoweringObjectFileMachO::getExplicitSectionGlobal(
const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const {
@@ -489,6 +518,9 @@
StringRef Segment, Section;
unsigned TAA = 0, StubSize = 0;
bool TAAParsed;
+
+ checkMachOComdat(GV);
+
std::string ErrorCode =
MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
TAA, TAAParsed, StubSize);
@@ -559,6 +591,7 @@
const MCSection *TargetLoweringObjectFileMachO::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler &Mang, const TargetMachine &TM) const {
+ checkMachOComdat(GV);
// Handle thread local data.
if (Kind.isThreadBSS()) return TLSBSSSection;
@@ -727,6 +760,50 @@
return Flags;
}
+const GlobalValue *getComdatGVForCOFF(const GlobalValue *GV) {
+ const Comdat *C = GV->getComdat();
+ assert(C && "expected GV to have a Comdat!");
+
+ StringRef ComdatGVName = C->getName();
+ const GlobalValue *ComdatGV = GV->getParent()->getNamedValue(ComdatGVName);
+ if (!ComdatGV)
+ report_fatal_error("Associative COMDAT symbol '" + ComdatGVName +
+ "' does not exist.");
+
+ if (ComdatGV->getComdat() != C)
+ report_fatal_error("Associative COMDAT symbol '" + ComdatGVName +
+ "' is not a key for it's COMDAT.");
+
+ return ComdatGV;
+}
+
+static int getSelectionForCOFF(const GlobalValue *GV) {
+ if (const Comdat *C = GV->getComdat()) {
+ const GlobalValue *ComdatKey = getComdatGVForCOFF(GV);
+ if (const auto *GA = dyn_cast<GlobalAlias>(ComdatKey))
+ ComdatKey = GA->getBaseObject();
+ if (ComdatKey == GV) {
+ switch (C->getSelectionKind()) {
+ case Comdat::Any:
+ return COFF::IMAGE_COMDAT_SELECT_ANY;
+ case Comdat::ExactMatch:
+ return COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH;
+ case Comdat::Largest:
+ return COFF::IMAGE_COMDAT_SELECT_LARGEST;
+ case Comdat::NoDuplicates:
+ return COFF::IMAGE_COMDAT_SELECT_NODUPLICATES;
+ case Comdat::SameSize:
+ return COFF::IMAGE_COMDAT_SELECT_SAME_SIZE;
+ }
+ } else {
+ return COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE;
+ }
+ } else if (GV->isWeakForLinker()) {
+ return COFF::IMAGE_COMDAT_SELECT_ANY;
+ }
+ return 0;
+}
+
const MCSection *TargetLoweringObjectFileCOFF::getExplicitSectionGlobal(
const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const {
@@ -734,11 +811,21 @@
unsigned Characteristics = getCOFFSectionFlags(Kind);
StringRef Name = GV->getSection();
StringRef COMDATSymName = "";
- if (GV->isWeakForLinker()) {
- Selection = COFF::IMAGE_COMDAT_SELECT_ANY;
- Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
- MCSymbol *Sym = TM.getSymbol(GV, Mang);
- COMDATSymName = Sym->getName();
+ if ((GV->isWeakForLinker() || GV->hasComdat()) && !Kind.isCommon()) {
+ Selection = getSelectionForCOFF(GV);
+ const GlobalValue *ComdatGV;
+ if (Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE)
+ ComdatGV = getComdatGVForCOFF(GV);
+ else
+ ComdatGV = GV;
+
+ if (!ComdatGV->hasPrivateLinkage()) {
+ MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang);
+ COMDATSymName = Sym->getName();
+ Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
+ } else {
+ Selection = 0;
+ }
}
return getContext().getCOFFSection(Name,
Characteristics,
@@ -775,17 +862,27 @@
// into a 'uniqued' section name, create and return the section now.
// Section names depend on the name of the symbol which is not feasible if the
// symbol has private linkage.
- if ((GV->isWeakForLinker() || EmitUniquedSection) &&
- !GV->hasPrivateLinkage() && !Kind.isCommon()) {
+ if ((GV->isWeakForLinker() || EmitUniquedSection || GV->hasComdat()) &&
+ !Kind.isCommon()) {
const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
unsigned Characteristics = getCOFFSectionFlags(Kind);
Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
- MCSymbol *Sym = TM.getSymbol(GV, Mang);
- return getContext().getCOFFSection(
- Name, Characteristics, Kind, Sym->getName(),
- GV->isWeakForLinker() ? COFF::IMAGE_COMDAT_SELECT_ANY
- : COFF::IMAGE_COMDAT_SELECT_NODUPLICATES);
+ int Selection = getSelectionForCOFF(GV);
+ if (!Selection)
+ Selection = COFF::IMAGE_COMDAT_SELECT_NODUPLICATES;
+ const GlobalValue *ComdatGV;
+ if (GV->hasComdat())
+ ComdatGV = getComdatGVForCOFF(GV);
+ else
+ ComdatGV = GV;
+
+ if (!ComdatGV->hasPrivateLinkage()) {
+ MCSymbol *Sym = TM.getSymbol(ComdatGV, Mang);
+ StringRef COMDATSymName = Sym->getName();
+ return getContext().getCOFFSection(Name, Characteristics, Kind,
+ COMDATSymName, Selection);
+ }
}
if (Kind.isText())
diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
index 398e3d5..87d26b1 100644
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -106,6 +106,7 @@
enum PrefixType {
GlobalPrefix,
+ ComdatPrefix,
LabelPrefix,
LocalPrefix,
NoPrefix
@@ -119,6 +120,7 @@
switch (Prefix) {
case NoPrefix: break;
case GlobalPrefix: OS << '@'; break;
+ case ComdatPrefix: OS << '$'; break;
case LabelPrefix: break;
case LocalPrefix: OS << '%'; break;
}
@@ -1165,8 +1167,15 @@
}
void AssemblyWriter::init() {
- if (TheModule)
- TypePrinter.incorporateTypes(*TheModule);
+ if (!TheModule)
+ return;
+ TypePrinter.incorporateTypes(*TheModule);
+ for (const Function &F : *TheModule)
+ if (const Comdat *C = F.getComdat())
+ Comdats.insert(C);
+ for (const GlobalVariable &GV : TheModule->globals())
+ if (const Comdat *C = GV.getComdat())
+ Comdats.insert(C);
}
@@ -1308,6 +1317,15 @@
printTypeIdentities();
+ // Output all comdats.
+ if (!Comdats.empty())
+ Out << '\n';
+ for (const Comdat *C : Comdats) {
+ printComdat(C);
+ if (C != Comdats.back())
+ Out << '\n';
+ }
+
// Output all globals.
if (!M->global_empty()) Out << '\n';
for (Module::const_global_iterator I = M->global_begin(), E = M->global_end();
@@ -1470,6 +1488,10 @@
PrintEscapedString(GV->getSection(), Out);
Out << '"';
}
+ if (GV->hasComdat()) {
+ Out << ", comdat ";
+ PrintLLVMName(Out, GV->getComdat()->getName(), ComdatPrefix);
+ }
if (GV->getAlignment())
Out << ", align " << GV->getAlignment();
@@ -1506,10 +1528,19 @@
writeOperand(Aliasee, !isa<ConstantExpr>(Aliasee));
}
+ if (GA->hasComdat()) {
+ Out << ", comdat ";
+ PrintLLVMName(Out, GA->getComdat()->getName(), ComdatPrefix);
+ }
+
printInfoComment(*GA);
Out << '\n';
}
+void AssemblyWriter::printComdat(const Comdat *C) {
+ C->print(Out);
+}
+
void AssemblyWriter::printTypeIdentities() {
if (TypePrinter.NumberedTypes.empty() &&
TypePrinter.NamedTypes.empty())
@@ -1647,6 +1678,10 @@
PrintEscapedString(F->getSection(), Out);
Out << '"';
}
+ if (F->hasComdat()) {
+ Out << " comdat ";
+ PrintLLVMName(Out, F->getComdat()->getName(), ComdatPrefix);
+ }
if (F->getAlignment())
Out << " align " << F->getAlignment();
if (F->hasGC())
@@ -2158,6 +2193,31 @@
W.printNamedMDNode(this);
}
+void Comdat::print(raw_ostream &ROS) const {
+ PrintLLVMName(ROS, getName(), ComdatPrefix);
+ ROS << " = comdat ";
+
+ switch (getSelectionKind()) {
+ case Comdat::Any:
+ ROS << "any";
+ break;
+ case Comdat::ExactMatch:
+ ROS << "exactmatch";
+ break;
+ case Comdat::Largest:
+ ROS << "largest";
+ break;
+ case Comdat::NoDuplicates:
+ ROS << "noduplicates";
+ break;
+ case Comdat::SameSize:
+ ROS << "samesize";
+ break;
+ }
+
+ ROS << '\n';
+}
+
void Type::print(raw_ostream &OS) const {
TypePrinting TP;
TP.print(const_cast<Type*>(this), OS);
@@ -2241,5 +2301,8 @@
// Module::dump() - Allow printing of Modules from the debugger.
void Module::dump() const { print(dbgs(), nullptr); }
+// \brief Allow printing of Comdats from the debugger.
+void Comdat::dump() const { print(dbgs()); }
+
// NamedMDNode::dump() - Allow printing of NamedMDNodes from the debugger.
void NamedMDNode::dump() const { print(dbgs()); }
diff --git a/llvm/lib/IR/AsmWriter.h b/llvm/lib/IR/AsmWriter.h
index b4ce6de..aef9c8a 100644
--- a/llvm/lib/IR/AsmWriter.h
+++ b/llvm/lib/IR/AsmWriter.h
@@ -16,6 +16,7 @@
#define LLVM_IR_ASSEMBLYWRITER_H
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SetVector.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/TypeFinder.h"
@@ -26,6 +27,7 @@
class BasicBlock;
class Function;
class GlobalValue;
+class Comdat;
class Module;
class NamedMDNode;
class Value;
@@ -70,6 +72,7 @@
SlotTracker &Machine;
TypePrinting TypePrinter;
AssemblyAnnotationWriter *AnnotationWriter;
+ SetVector<const Comdat *> Comdats;
public:
/// Construct an AssemblyWriter with an external SlotTracker
@@ -101,6 +104,7 @@
void printTypeIdentities();
void printGlobal(const GlobalVariable *GV);
void printAlias(const GlobalAlias *GV);
+ void printComdat(const Comdat *C);
void printFunction(const Function *F);
void printArgument(const Argument *FA, AttributeSet Attrs, unsigned Idx);
void printBasicBlock(const BasicBlock *BB);
diff --git a/llvm/lib/IR/CMakeLists.txt b/llvm/lib/IR/CMakeLists.txt
index b027ae5..38a80b1 100644
--- a/llvm/lib/IR/CMakeLists.txt
+++ b/llvm/lib/IR/CMakeLists.txt
@@ -3,6 +3,7 @@
Attributes.cpp
AutoUpgrade.cpp
BasicBlock.cpp
+ Comdat.cpp
ConstantFold.cpp
ConstantRange.cpp
Constants.cpp
diff --git a/llvm/lib/IR/Comdat.cpp b/llvm/lib/IR/Comdat.cpp
new file mode 100644
index 0000000..80715ff
--- /dev/null
+++ b/llvm/lib/IR/Comdat.cpp
@@ -0,0 +1,25 @@
+//===-- Comdat.cpp - Implement Metadata classes --------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Comdat class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/Comdat.h"
+#include "llvm/ADT/StringMap.h"
+using namespace llvm;
+
+Comdat::Comdat(SelectionKind SK, StringMapEntry<Comdat> *Name)
+ : Name(Name), SK(SK) {}
+
+Comdat::Comdat(Comdat &&C) : Name(C.Name), SK(C.SK) {}
+
+Comdat::Comdat() : Name(nullptr), SK(Comdat::Any) {}
+
+StringRef Comdat::getName() const { return Name->first(); }
diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index 5410cc0..244e3e4 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -59,15 +59,10 @@
setDLLStorageClass(Src->getDLLStorageClass());
}
-static const GlobalObject *getBaseObject(const Constant &C) {
- // FIXME: We should probably return a base + offset pair for non-zero GEPs.
- return dyn_cast<GlobalObject>(C.stripPointerCasts());
-}
-
unsigned GlobalValue::getAlignment() const {
if (auto *GA = dyn_cast<GlobalAlias>(this)) {
// In general we cannot compute this at the IR level, but we try.
- if (const GlobalObject *GO = getBaseObject(*GA->getAliasee()))
+ if (const GlobalObject *GO = GA->getBaseObject())
return GO->getAlignment();
// FIXME: we should also be able to handle:
@@ -96,13 +91,23 @@
const char *GlobalValue::getSection() const {
if (auto *GA = dyn_cast<GlobalAlias>(this)) {
// In general we cannot compute this at the IR level, but we try.
- if (const GlobalObject *GO = getBaseObject(*GA->getAliasee()))
+ if (const GlobalObject *GO = GA->getBaseObject())
return GO->getSection();
return "";
}
return cast<GlobalObject>(this)->getSection();
}
+Comdat *GlobalValue::getComdat() {
+ if (auto *GA = dyn_cast<GlobalAlias>(this)) {
+ // In general we cannot compute this at the IR level, but we try.
+ if (const GlobalObject *GO = GA->getBaseObject())
+ return const_cast<GlobalObject *>(GO)->getComdat();
+ return nullptr;
+ }
+ return cast<GlobalObject>(this)->getComdat();
+}
+
void GlobalObject::setSection(StringRef S) { Section = S; }
bool GlobalValue::isDeclaration() const {
diff --git a/llvm/lib/IR/Module.cpp b/llvm/lib/IR/Module.cpp
index 9889f00..d853bf4 100644
--- a/llvm/lib/IR/Module.cpp
+++ b/llvm/lib/IR/Module.cpp
@@ -453,3 +453,11 @@
return dwarf::DWARF_VERSION;
return cast<ConstantInt>(Val)->getZExtValue();
}
+
+Comdat *Module::getOrInsertComdat(StringRef Name) {
+ Comdat C;
+ StringMapEntry<Comdat> &Entry =
+ ComdatSymTab.GetOrCreateValue(Name, std::move(C));
+ Entry.second.Name = &Entry;
+ return &Entry.second;
+}
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index ad3c29c..24f3acb 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -107,6 +107,12 @@
OS << ' ' << *T;
}
+ void WriteComdat(const Comdat *C) {
+ if (!C)
+ return;
+ OS << *C;
+ }
+
// CheckFailed - A check failed, so print out the condition and the message
// that failed. This provides a nice place to put a breakpoint if you want
// to see why something is not correct.
@@ -138,6 +144,12 @@
WriteType(T3);
Broken = true;
}
+
+ void CheckFailed(const Twine &Message, const Comdat *C) {
+ OS << Message.str() << "\n";
+ WriteComdat(C);
+ Broken = true;
+ }
};
class Verifier : public InstVisitor<Verifier>, VerifierSupport {
friend class InstVisitor<Verifier>;
@@ -230,6 +242,9 @@
I != E; ++I)
visitNamedMDNode(*I);
+ for (const StringMapEntry<Comdat> &SMEC : M.getComdatSymbolTable())
+ visitComdat(SMEC.getValue());
+
visitModuleFlags(M);
visitModuleIdents(M);
@@ -246,6 +261,7 @@
const GlobalAlias &A, const Constant &C);
void visitNamedMDNode(const NamedMDNode &NMD);
void visitMDNode(MDNode &MD, Function *F);
+ void visitComdat(const Comdat &C);
void visitModuleIdents(const Module &M);
void visitModuleFlags(const Module &M);
void visitModuleFlag(const MDNode *Op,
@@ -387,6 +403,7 @@
"'common' global must have a zero initializer!", &GV);
Assert1(!GV.isConstant(), "'common' global may not be marked constant!",
&GV);
+ Assert1(!GV.hasComdat(), "'common' global may not be in a Comdat!", &GV);
}
} else {
Assert1(GV.hasExternalLinkage() || GV.hasExternalWeakLinkage(),
@@ -578,6 +595,22 @@
}
}
+void Verifier::visitComdat(const Comdat &C) {
+ // All Comdat::SelectionKind values other than Comdat::Any require a
+ // GlobalValue with the same name as the Comdat.
+ const GlobalValue *GV = M->getNamedValue(C.getName());
+ if (C.getSelectionKind() != Comdat::Any)
+ Assert1(GV,
+ "comdat selection kind requires a global value with the same name",
+ &C);
+ // The Module is invalid if the GlobalValue has local linkage. Allowing
+ // otherwise opens us up to seeing the underling global value get renamed if
+ // collisions occur.
+ if (GV)
+ Assert1(!GV->hasLocalLinkage(), "comdat global value has local linkage",
+ GV);
+}
+
void Verifier::visitModuleIdents(const Module &M) {
const NamedMDNode *Idents = M.getNamedMetadata("llvm.ident");
if (!Idents)
diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 688b13f..eb73a49 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -426,6 +426,18 @@
return true;
}
+ bool getComdatLeader(Module *M, StringRef ComdatName,
+ const GlobalVariable *&GVar);
+ bool computeResultingSelectionKind(StringRef ComdatName,
+ Comdat::SelectionKind Src,
+ Comdat::SelectionKind Dst,
+ Comdat::SelectionKind &Result,
+ bool &LinkFromSrc);
+ std::map<const Comdat *, std::pair<Comdat::SelectionKind, bool>>
+ ComdatsChosen;
+ bool getComdatResult(const Comdat *SrcC, Comdat::SelectionKind &SK,
+ bool &LinkFromSrc);
+
/// getLinkageResult - This analyzes the two global values and determines
/// what the result will look like in the destination module.
bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
@@ -534,6 +546,115 @@
return DF;
}
+bool ModuleLinker::getComdatLeader(Module *M, StringRef ComdatName,
+ const GlobalVariable *&GVar) {
+ const GlobalValue *GVal = M->getNamedValue(ComdatName);
+ if (const auto *GA = dyn_cast_or_null<GlobalAlias>(GVal)) {
+ GVal = GA->getBaseObject();
+ if (!GVal)
+ // We cannot resolve the size of the aliasee yet.
+ return emitError("Linking COMDATs named '" + ComdatName +
+ "': COMDAT key involves incomputable alias size.");
+ }
+
+ GVar = dyn_cast_or_null<GlobalVariable>(GVal);
+ if (!GVar)
+ return emitError(
+ "Linking COMDATs named '" + ComdatName +
+ "': GlobalVariable required for data dependent selection!");
+
+ return false;
+}
+
+bool ModuleLinker::computeResultingSelectionKind(StringRef ComdatName,
+ Comdat::SelectionKind Src,
+ Comdat::SelectionKind Dst,
+ Comdat::SelectionKind &Result,
+ bool &LinkFromSrc) {
+ // The ability to mix Comdat::SelectionKind::Any with
+ // Comdat::SelectionKind::Largest is a behavior that comes from COFF.
+ bool DstAnyOrLargest = Dst == Comdat::SelectionKind::Any ||
+ Dst == Comdat::SelectionKind::Largest;
+ bool SrcAnyOrLargest = Src == Comdat::SelectionKind::Any ||
+ Src == Comdat::SelectionKind::Largest;
+ if (DstAnyOrLargest && SrcAnyOrLargest) {
+ if (Dst == Comdat::SelectionKind::Largest ||
+ Src == Comdat::SelectionKind::Largest)
+ Result = Comdat::SelectionKind::Largest;
+ else
+ Result = Comdat::SelectionKind::Any;
+ } else if (Src == Dst) {
+ Result = Dst;
+ } else {
+ return emitError("Linking COMDATs named '" + ComdatName +
+ "': invalid selection kinds!");
+ }
+
+ switch (Result) {
+ case Comdat::SelectionKind::Any:
+ // Go with Dst.
+ LinkFromSrc = false;
+ break;
+ case Comdat::SelectionKind::NoDuplicates:
+ return emitError("Linking COMDATs named '" + ComdatName +
+ "': noduplicates has been violated!");
+ case Comdat::SelectionKind::ExactMatch:
+ case Comdat::SelectionKind::Largest:
+ case Comdat::SelectionKind::SameSize: {
+ const GlobalVariable *DstGV;
+ const GlobalVariable *SrcGV;
+ if (getComdatLeader(DstM, ComdatName, DstGV) ||
+ getComdatLeader(SrcM, ComdatName, SrcGV))
+ return true;
+
+ const DataLayout *DstDL = DstM->getDataLayout();
+ const DataLayout *SrcDL = SrcM->getDataLayout();
+ if (!DstDL || !SrcDL) {
+ return emitError(
+ "Linking COMDATs named '" + ComdatName +
+ "': can't do size dependent selection without DataLayout!");
+ }
+ uint64_t DstSize =
+ DstDL->getTypeAllocSize(DstGV->getType()->getPointerElementType());
+ uint64_t SrcSize =
+ SrcDL->getTypeAllocSize(SrcGV->getType()->getPointerElementType());
+ if (Result == Comdat::SelectionKind::ExactMatch) {
+ if (SrcGV->getInitializer() != DstGV->getInitializer())
+ return emitError("Linking COMDATs named '" + ComdatName +
+ "': ExactMatch violated!");
+ LinkFromSrc = false;
+ } else if (Result == Comdat::SelectionKind::Largest) {
+ LinkFromSrc = SrcSize > DstSize;
+ } else if (Result == Comdat::SelectionKind::SameSize) {
+ if (SrcSize != DstSize)
+ return emitError("Linking COMDATs named '" + ComdatName +
+ "': SameSize violated!");
+ LinkFromSrc = false;
+ } else {
+ llvm_unreachable("unknown selection kind");
+ }
+ break;
+ }
+ }
+
+ return false;
+}
+
+bool ModuleLinker::getComdatResult(const Comdat *SrcC,
+ Comdat::SelectionKind &Result,
+ bool &LinkFromSrc) {
+ StringRef ComdatName = SrcC->getName();
+ Module::ComdatSymTabType &ComdatSymTab = DstM->getComdatSymbolTable();
+ Module::ComdatSymTabType::iterator DstCI = ComdatSymTab.find(ComdatName);
+ if (DstCI != ComdatSymTab.end()) {
+ const Comdat *DstC = &DstCI->second;
+ Comdat::SelectionKind SSK = SrcC->getSelectionKind();
+ Comdat::SelectionKind DSK = DstC->getSelectionKind();
+ if (computeResultingSelectionKind(ComdatName, SSK, DSK, Result, LinkFromSrc))
+ return true;
+ }
+ return false;
+}
/// getLinkageResult - This analyzes the two global values and determines what
/// the result will look like in the destination module. In particular, it
@@ -764,34 +885,47 @@
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
bool HasUnnamedAddr = SGV->hasUnnamedAddr();
+ bool LinkFromSrc = false;
+ Comdat *DC = nullptr;
+ if (const Comdat *SC = SGV->getComdat()) {
+ Comdat::SelectionKind SK;
+ std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
+ DC = DstM->getOrInsertComdat(SC->getName());
+ DC->setSelectionKind(SK);
+ }
+
if (DGV) {
- // Concatenation of appending linkage variables is magic and handled later.
- if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
- return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
+ if (!DC) {
+ // Concatenation of appending linkage variables is magic and handled later.
+ if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
+ return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
- // Determine whether linkage of these two globals follows the source
- // module's definition or the destination module's definition.
- GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
- GlobalValue::VisibilityTypes NV;
- bool LinkFromSrc = false;
- if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
- return true;
- NewVisibility = NV;
- HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
+ // Determine whether linkage of these two globals follows the source
+ // module's definition or the destination module's definition.
+ GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
+ GlobalValue::VisibilityTypes NV;
+ if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
+ return true;
+ NewVisibility = NV;
+ HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
- // If we're not linking from the source, then keep the definition that we
- // have.
+ // If we're not linking from the source, then keep the definition that we
+ // have.
+ if (!LinkFromSrc) {
+ // Special case for const propagation.
+ if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
+ if (DGVar->isDeclaration() && SGV->isConstant() &&
+ !DGVar->isConstant())
+ DGVar->setConstant(true);
+
+ // Set calculated linkage, visibility and unnamed_addr.
+ DGV->setLinkage(NewLinkage);
+ DGV->setVisibility(*NewVisibility);
+ DGV->setUnnamedAddr(HasUnnamedAddr);
+ }
+ }
+
if (!LinkFromSrc) {
- // Special case for const propagation.
- if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
- if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
- DGVar->setConstant(true);
-
- // Set calculated linkage, visibility and unnamed_addr.
- DGV->setLinkage(NewLinkage);
- DGV->setVisibility(*NewVisibility);
- DGV->setUnnamedAddr(HasUnnamedAddr);
-
// Make sure to remember this mapping.
ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
@@ -803,6 +937,12 @@
}
}
+ // If the Comdat this variable was inside of wasn't selected, skip it.
+ if (DC && !DGV && !LinkFromSrc) {
+ DoNotLinkFromSource.insert(SGV);
+ return false;
+ }
+
// No linking to be performed or linking from the source: simply create an
// identical version of the symbol over in the dest module... the
// initializer will be filled in later by LinkGlobalInits.
@@ -818,6 +958,9 @@
NewDGV->setVisibility(*NewVisibility);
NewDGV->setUnnamedAddr(HasUnnamedAddr);
+ if (DC)
+ NewDGV->setComdat(DC);
+
if (DGV) {
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
DGV->eraseFromParent();
@@ -835,21 +978,33 @@
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
bool HasUnnamedAddr = SF->hasUnnamedAddr();
+ bool LinkFromSrc = false;
+ Comdat *DC = nullptr;
+ if (const Comdat *SC = SF->getComdat()) {
+ Comdat::SelectionKind SK;
+ std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
+ DC = DstM->getOrInsertComdat(SC->getName());
+ DC->setSelectionKind(SK);
+ }
+
if (DGV) {
- GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
- bool LinkFromSrc = false;
- GlobalValue::VisibilityTypes NV;
- if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
- return true;
- NewVisibility = NV;
- HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
+ if (!DC) {
+ GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
+ GlobalValue::VisibilityTypes NV;
+ if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
+ return true;
+ NewVisibility = NV;
+ HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
+
+ if (!LinkFromSrc) {
+ // Set calculated linkage
+ DGV->setLinkage(NewLinkage);
+ DGV->setVisibility(*NewVisibility);
+ DGV->setUnnamedAddr(HasUnnamedAddr);
+ }
+ }
if (!LinkFromSrc) {
- // Set calculated linkage
- DGV->setLinkage(NewLinkage);
- DGV->setVisibility(*NewVisibility);
- DGV->setUnnamedAddr(HasUnnamedAddr);
-
// Make sure to remember this mapping.
ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
@@ -869,6 +1024,12 @@
return false;
}
+ // If the Comdat this function was inside of wasn't selected, skip it.
+ if (DC && !DGV && !LinkFromSrc) {
+ DoNotLinkFromSource.insert(SF);
+ return false;
+ }
+
// If there is no linkage to be performed or we are linking from the source,
// bring SF over.
Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
@@ -878,6 +1039,9 @@
NewDF->setVisibility(*NewVisibility);
NewDF->setUnnamedAddr(HasUnnamedAddr);
+ if (DC)
+ NewDF->setComdat(DC);
+
if (DGV) {
// Any uses of DF need to change to NewDF, with cast.
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
@@ -895,21 +1059,33 @@
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
bool HasUnnamedAddr = SGA->hasUnnamedAddr();
+ bool LinkFromSrc = false;
+ Comdat *DC = nullptr;
+ if (const Comdat *SC = SGA->getComdat()) {
+ Comdat::SelectionKind SK;
+ std::tie(SK, LinkFromSrc) = ComdatsChosen[SC];
+ DC = DstM->getOrInsertComdat(SC->getName());
+ DC->setSelectionKind(SK);
+ }
+
if (DGV) {
- GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
- GlobalValue::VisibilityTypes NV;
- bool LinkFromSrc = false;
- if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
- return true;
- NewVisibility = NV;
- HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
+ if (!DC) {
+ GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
+ GlobalValue::VisibilityTypes NV;
+ if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
+ return true;
+ NewVisibility = NV;
+ HasUnnamedAddr = HasUnnamedAddr && DGV->hasUnnamedAddr();
+
+ if (!LinkFromSrc) {
+ // Set calculated linkage.
+ DGV->setLinkage(NewLinkage);
+ DGV->setVisibility(*NewVisibility);
+ DGV->setUnnamedAddr(HasUnnamedAddr);
+ }
+ }
if (!LinkFromSrc) {
- // Set calculated linkage.
- DGV->setLinkage(NewLinkage);
- DGV->setVisibility(*NewVisibility);
- DGV->setUnnamedAddr(HasUnnamedAddr);
-
// Make sure to remember this mapping.
ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
@@ -920,6 +1096,12 @@
}
}
+ // If the Comdat this alias was inside of wasn't selected, skip it.
+ if (DC && !DGV && !LinkFromSrc) {
+ DoNotLinkFromSource.insert(SGA);
+ return false;
+ }
+
// If there is no linkage to be performed or we're linking from the source,
// bring over SGA.
auto *PTy = cast<PointerType>(TypeMap.get(SGA->getType()));
@@ -1254,6 +1436,18 @@
// Loop over all of the linked values to compute type mappings.
computeTypeMapping();
+ ComdatsChosen.clear();
+ for (const StringMapEntry<llvm::Comdat> &SMEC : SrcM->getComdatSymbolTable()) {
+ const Comdat &C = SMEC.getValue();
+ if (ComdatsChosen.count(&C))
+ continue;
+ Comdat::SelectionKind SK;
+ bool LinkFromSrc;
+ if (getComdatResult(&C, SK, LinkFromSrc))
+ return true;
+ ComdatsChosen[&C] = std::make_pair(SK, LinkFromSrc);
+ }
+
// Insert all of the globals in src into the DstM module... without linking
// initializers (which could refer to functions not yet mapped over).
for (Module::global_iterator I = SrcM->global_begin(),
diff --git a/llvm/lib/Transforms/IPO/GlobalDCE.cpp b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
index 57481e1..7e7a4c0 100644
--- a/llvm/lib/Transforms/IPO/GlobalDCE.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
@@ -77,13 +77,19 @@
// Remove empty functions from the global ctors list.
Changed |= optimizeGlobalCtorsList(M, isEmptyFunction);
+ typedef std::multimap<const Comdat *, GlobalValue *> ComdatGVPairsTy;
+ ComdatGVPairsTy ComdatGVPairs;
+
// Loop over the module, adding globals which are obviously necessary.
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
Changed |= RemoveUnusedGlobalValue(*I);
// Functions with external linkage are needed if they have a body
- if (!I->isDiscardableIfUnused() &&
- !I->isDeclaration() && !I->hasAvailableExternallyLinkage())
- GlobalIsNeeded(I);
+ if (!I->isDeclaration() && !I->hasAvailableExternallyLinkage()) {
+ if (!I->isDiscardableIfUnused())
+ GlobalIsNeeded(I);
+ else if (const Comdat *C = I->getComdat())
+ ComdatGVPairs.insert(std::make_pair(C, I));
+ }
}
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
@@ -91,17 +97,38 @@
Changed |= RemoveUnusedGlobalValue(*I);
// Externally visible & appending globals are needed, if they have an
// initializer.
- if (!I->isDiscardableIfUnused() &&
- !I->isDeclaration() && !I->hasAvailableExternallyLinkage())
- GlobalIsNeeded(I);
+ if (!I->isDeclaration() && !I->hasAvailableExternallyLinkage()) {
+ if (!I->isDiscardableIfUnused())
+ GlobalIsNeeded(I);
+ else if (const Comdat *C = I->getComdat())
+ ComdatGVPairs.insert(std::make_pair(C, I));
+ }
}
for (Module::alias_iterator I = M.alias_begin(), E = M.alias_end();
I != E; ++I) {
Changed |= RemoveUnusedGlobalValue(*I);
// Externally visible aliases are needed.
- if (!I->isDiscardableIfUnused())
+ if (!I->isDiscardableIfUnused()) {
GlobalIsNeeded(I);
+ } else if (const Comdat *C = I->getComdat()) {
+ ComdatGVPairs.insert(std::make_pair(C, I));
+ }
+ }
+
+ for (ComdatGVPairsTy::iterator I = ComdatGVPairs.begin(),
+ E = ComdatGVPairs.end();
+ I != E;) {
+ ComdatGVPairsTy::iterator UB = ComdatGVPairs.upper_bound(I->first);
+ bool CanDiscard = std::all_of(I, UB, [](ComdatGVPairsTy::value_type Pair) {
+ return Pair.second->isDiscardableIfUnused();
+ });
+ if (!CanDiscard) {
+ std::for_each(I, UB, [this](ComdatGVPairsTy::value_type Pair) {
+ GlobalIsNeeded(Pair.second);
+ });
+ }
+ I = UB;
}
// Now that all globals which are needed are in the AliveGlobals set, we loop
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 36c04f0..dc9b2a8 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -17,6 +17,7 @@
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ConstantFolding.h"
@@ -1699,9 +1700,6 @@
/// possible. If we make a change, return true.
bool GlobalOpt::ProcessGlobal(GlobalVariable *GV,
Module::global_iterator &GVI) {
- if (!GV->isDiscardableIfUnused())
- return false;
-
// Do more involved optimizations if the global is internal.
GV->removeDeadConstantUsers();
@@ -1944,6 +1942,13 @@
bool GlobalOpt::OptimizeGlobalVars(Module &M) {
bool Changed = false;
+
+ SmallSet<const Comdat *, 8> NotDiscardableComdats;
+ for (const GlobalVariable &GV : M.globals())
+ if (const Comdat *C = GV.getComdat())
+ if (!GV.isDiscardableIfUnused())
+ NotDiscardableComdats.insert(C);
+
for (Module::global_iterator GVI = M.global_begin(), E = M.global_end();
GVI != E; ) {
GlobalVariable *GV = GVI++;
@@ -1958,7 +1963,12 @@
GV->setInitializer(New);
}
- Changed |= ProcessGlobal(GV, GVI);
+ if (GV->isDiscardableIfUnused()) {
+ if (const Comdat *C = GV->getComdat())
+ if (NotDiscardableComdats.count(C))
+ continue;
+ Changed |= ProcessGlobal(GV, GVI);
+ }
}
return Changed;
}