diff options
| -rw-r--r-- | llvm/lib/LTO/LTO.cpp | 21 | ||||
| -rw-r--r-- | llvm/test/LTO/Resolution/X86/Inputs/link-odr-availextern-odr.ll | 6 | ||||
| -rw-r--r-- | llvm/test/LTO/Resolution/X86/link-odr-availextern.ll | 13 |
3 files changed, 36 insertions, 4 deletions
diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp index 4d0c039891e..df19ded398d 100644 --- a/llvm/lib/LTO/LTO.cpp +++ b/llvm/lib/LTO/LTO.cpp @@ -446,6 +446,11 @@ Error LTO::addRegularLTO(BitcodeModule BM, const SymbolResolution *&ResI, if (GV.hasAppendingLinkage()) Keep.push_back(&GV); + DenseSet<GlobalObject *> AliasedGlobals; + for (auto &GA : M.aliases()) + if (GlobalObject *GO = GA.getBaseObject()) + AliasedGlobals.insert(GO); + for (const InputFile::Symbol &Sym : make_range(InputFile::symbol_iterator(SymTab.symbols().begin(), SymTab, nullptr), @@ -471,13 +476,21 @@ Error LTO::addRegularLTO(BitcodeModule BM, const SymbolResolution *&ResI, GV->setLinkage(GlobalValue::WeakODRLinkage); break; } - } else if (GV->hasAvailableExternallyLinkage()) { - // We can link available_externally symbols even if they are - // non-prevailing. + } else if (isa<GlobalObject>(GV) && + (GV->hasLinkOnceODRLinkage() || GV->hasWeakODRLinkage() || + GV->hasAvailableExternallyLinkage()) && + !AliasedGlobals.count(cast<GlobalObject>(GV))) { + // Either of the above three types of linkage indicates that the + // chosen prevailing symbol will have the same semantics as this copy of + // the symbol, so we can link it with available_externally linkage. We + // only need to do this if the symbol is undefined. GlobalValue *CombinedGV = RegularLTO.CombinedModule->getNamedValue(GV->getName()); - if (!CombinedGV || CombinedGV->isDeclaration()) + if (!CombinedGV || CombinedGV->isDeclaration()) { Keep.push_back(GV); + GV->setLinkage(GlobalValue::AvailableExternallyLinkage); + cast<GlobalObject>(GV)->setComdat(nullptr); + } } } // Common resolution: collect the maximum size/alignment over all commons. diff --git a/llvm/test/LTO/Resolution/X86/Inputs/link-odr-availextern-odr.ll b/llvm/test/LTO/Resolution/X86/Inputs/link-odr-availextern-odr.ll new file mode 100644 index 00000000000..76e745a444f --- /dev/null +++ b/llvm/test/LTO/Resolution/X86/Inputs/link-odr-availextern-odr.ll @@ -0,0 +1,6 @@ +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +define linkonce_odr i32 @f() { + ret i32 2 +} diff --git a/llvm/test/LTO/Resolution/X86/link-odr-availextern.ll b/llvm/test/LTO/Resolution/X86/link-odr-availextern.ll index 4af79b64b2a..5a3cc3884db 100644 --- a/llvm/test/LTO/Resolution/X86/link-odr-availextern.ll +++ b/llvm/test/LTO/Resolution/X86/link-odr-availextern.ll @@ -3,16 +3,29 @@ ; RUN: llvm-as %s -o %t1 ; RUN: llvm-as %S/Inputs/link-odr-availextern-ae.ll -o %t2ae +; RUN: llvm-as %S/Inputs/link-odr-availextern-odr.ll -o %t2odr ; RUN: llvm-lto2 -o %t3 %t1 %t2ae -r %t1,f,p -r %t2ae,f, -save-temps ; RUN: llvm-dis < %t3.0.0.preopt.bc -o - | FileCheck --check-prefix=PREVAILING %s +; RUN: llvm-lto2 -o %t3 %t1 %t2odr -r %t1,f,p -r %t2odr,f, -save-temps +; RUN: llvm-dis < %t3.0.0.preopt.bc -o - | FileCheck --check-prefix=PREVAILING %s + ; RUN: llvm-lto2 -o %t3 %t2ae %t1 -r %t1,f,p -r %t2ae,f, -save-temps ; RUN: llvm-dis < %t3.0.0.preopt.bc -o - | FileCheck --check-prefix=PREVAILING %s +; RUN: llvm-lto2 -o %t3 %t2odr %t1 -r %t1,f,p -r %t2odr,f, -save-temps +; RUN: llvm-dis < %t3.0.0.preopt.bc -o - | FileCheck --check-prefix=PREVAILING %s + ; RUN: llvm-lto2 -o %t3 %t2ae -r %t2ae,f, -save-temps ; RUN: llvm-dis < %t3.0.0.preopt.bc -o - | FileCheck --check-prefix=NONPREVAILING %s +; RUN: llvm-lto2 -o %t3 %t2odr -r %t2odr,f, -save-temps +; RUN: llvm-dis < %t3.0.0.preopt.bc -o - | FileCheck --check-prefix=NONPREVAILING %s + +; RUN: llvm-lto2 -o %t3 %t2odr %t1 -r %t1,f, -r %t2odr,f, -save-temps +; RUN: llvm-dis < %t3.0.0.preopt.bc -o - | FileCheck --check-prefix=NONPREVAILING %s + target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" |
