<div dir="ltr">List of exported symbols can be given in a mean that the only linker is able to know (/export option of the linker or a module definition file), so we still need to do something like this for dllexport'ed symbols.</div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jun 3, 2015 at 10:21 PM, Peter Collingbourne <span dir="ltr"><<a href="mailto:peter@pcc.me.uk" target="_blank">peter@pcc.me.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">In any case, it looks like the internalizer already has code to prevent<br>
internalization of dllexported symbols (see the shouldInternalize function<br>
in lib/Transforms/IPO/Internalize.cpp).<br>
<br>
Peter<br>
<div class="HOEnZb"><div class="h5"><br>
On Wed, Jun 03, 2015 at 09:10:27PM -0700, Rui Ueyama wrote:<br>
> It doesn't support DLL yet.<br>
><br>
> On Wed, Jun 3, 2015 at 8:40 PM, David Majnemer <<a href="mailto:david.majnemer@gmail.com">david.majnemer@gmail.com</a>><br>
> wrote:<br>
><br>
> > Do you already do the same for exported symbols?<br>
> ><br>
> ><br>
> > On Wednesday, June 3, 2015, Rui Ueyama <<a href="mailto:ruiu@google.com">ruiu@google.com</a>> wrote:<br>
> ><br>
> >> Author: ruiu<br>
> >> Date: Wed Jun 3 21:12:16 2015<br>
> >> New Revision: 239005<br>
> >><br>
> >> URL: <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject-3Frev-3D239005-26view-3Drev&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=J8bdDGfWVk_gfY7-5mLYocIXsy4ngiPJpt0zja1UpRQ&e=" target="_blank">http://llvm.org/viewvc/llvm-project?rev=239005&view=rev</a><br>
> >> Log:<br>
> >> COFF: /include'd symbols must be preserved.<br>
> >><br>
> >> Not only entry point symbol but also symbols specified by /include<br>
> >> option must be preserved, as they will never be dead-stripped.<br>
> >><br>
> >> <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__reviews.llvm.org_D10220&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=6zaWp5lDtpZOPtgDNF0aI_1P80ukgAdjAVtoE9Rc4dg&e=" target="_blank">http://reviews.llvm.org/D10220</a><br>
> >><br>
> >> Modified:<br>
> >> lld/trunk/COFF/Config.h<br>
> >> lld/trunk/COFF/Driver.cpp<br>
> >> lld/trunk/COFF/SymbolTable.cpp<br>
> >> lld/trunk/COFF/Writer.cpp<br>
> >> lld/trunk/COFF/Writer.h<br>
> >> lld/trunk/test/COFF/lto.ll<br>
> >><br>
> >> Modified: lld/trunk/COFF/Config.h<br>
> >> URL:<br>
> >> <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_COFF_Config.h-3Frev-3D239005-26r1-3D239004-26r2-3D239005-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=IK_vn2M38_nDhBbvwDPUWCF8p9jOu6JFBRXgBL9cboo&e=" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Config.h?rev=239005&r1=239004&r2=239005&view=diff</a><br>
> >><br>
> >> ==============================================================================<br>
> >> --- lld/trunk/COFF/Config.h (original)<br>
> >> +++ lld/trunk/COFF/Config.h Wed Jun 3 21:12:16 2015<br>
> >> @@ -27,7 +27,10 @@ public:<br>
> >> llvm::COFF::MachineTypes MachineType =<br>
> >> llvm::COFF::IMAGE_FILE_MACHINE_AMD64;<br>
> >> bool Verbose = false;<br>
> >> WindowsSubsystem Subsystem = llvm::COFF::IMAGE_SUBSYSTEM_UNKNOWN;<br>
> >> - std::string EntryName;<br>
> >> + StringRef EntryName;<br>
> >> +<br>
> >> + // Symbols in this set are considered as live by the garbage collector.<br>
> >> + std::set<StringRef> GCRoots;<br>
> >><br>
> >> std::set<StringRef> NoDefaultLibs;<br>
> >> bool NoDefaultLibAll = false;<br>
> >><br>
> >> Modified: lld/trunk/COFF/Driver.cpp<br>
> >> URL:<br>
> >> <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_COFF_Driver.cpp-3Frev-3D239005-26r1-3D239004-26r2-3D239005-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=VloDHx--wLTaQHYE_MthUw9xpfGA3gBvws5mS9AMgzU&e=" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Driver.cpp?rev=239005&r1=239004&r2=239005&view=diff</a><br>
> >><br>
> >> ==============================================================================<br>
> >> --- lld/trunk/COFF/Driver.cpp (original)<br>
> >> +++ lld/trunk/COFF/Driver.cpp Wed Jun 3 21:12:16 2015<br>
> >> @@ -312,8 +312,11 @@ bool LinkerDriver::link(int Argc, const<br>
> >><br>
> >> // Add undefined symbols given via the command line.<br>
> >> // (/include is equivalent to Unix linker's -u option.)<br>
> >> - for (auto *Arg : Args->filtered(OPT_incl))<br>
> >> - Symtab.addUndefined(Arg->getValue());<br>
> >> + for (auto *Arg : Args->filtered(OPT_incl)) {<br>
> >> + StringRef Sym = Arg->getValue();<br>
> >> + Symtab.addUndefined(Sym);<br>
> >> + Config->GCRoots.insert(Sym);<br>
> >> + }<br>
> >><br>
> >> // Parse all input files and put all symbols to the symbol table.<br>
> >> // The symbol table will take care of name resolution.<br>
> >> @@ -362,11 +365,14 @@ bool LinkerDriver::link(int Argc, const<br>
> >> }<br>
> >> Config->EntryName = EntryOrErr.get();<br>
> >> }<br>
> >> + Config->GCRoots.insert(Config->EntryName);<br>
> >><br>
> >> // Make sure we have resolved all symbols.<br>
> >> if (Symtab.reportRemainingUndefines())<br>
> >> return false;<br>
> >><br>
> >> + // Do LTO by compiling bitcode input files to a native COFF file<br>
> >> + // then link that file.<br>
> >> if (auto EC = Symtab.addCombinedLTOObject()) {<br>
> >> llvm::errs() << EC.message() << "\n";<br>
> >> return false;<br>
> >><br>
> >> Modified: lld/trunk/COFF/SymbolTable.cpp<br>
> >> URL:<br>
> >> <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_COFF_SymbolTable.cpp-3Frev-3D239005-26r1-3D239004-26r2-3D239005-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=Xgg00MVMI5AgmDmlMh804Vb-AIc6EPEINu7HfRxYIL0&e=" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/SymbolTable.cpp?rev=239005&r1=239004&r2=239005&view=diff</a><br>
> >><br>
> >> ==============================================================================<br>
> >> --- lld/trunk/COFF/SymbolTable.cpp (original)<br>
> >> +++ lld/trunk/COFF/SymbolTable.cpp Wed Jun 3 21:12:16 2015<br>
> >> @@ -227,20 +227,17 @@ std::error_code SymbolTable::addCombined<br>
> >> return std::error_code();<br>
> >><br>
> >> llvm::LTOCodeGenerator CG;<br>
> >> - std::set<DefinedBitcode *> PreservedBitcodeSymbols;<br>
> >><br>
> >> // All symbols referenced by non-bitcode objects must be preserved.<br>
> >> for (std::unique_ptr<ObjectFile> &File : ObjectFiles)<br>
> >> for (SymbolBody *Body : File->getSymbols())<br>
> >> if (auto *S = dyn_cast<DefinedBitcode>(Body->getReplacement()))<br>
> >> - PreservedBitcodeSymbols.insert(S);<br>
> >> + CG.addMustPreserveSymbol(S->getName());<br>
> >><br>
> >> - // Likewise for the linker-generated reference to the entry point.<br>
> >> - if (auto *S =<br>
> >> dyn_cast<DefinedBitcode>(Symtab[Config->EntryName]->Body))<br>
> >> - PreservedBitcodeSymbols.insert(S);<br>
> >> -<br>
> >> - for (DefinedBitcode *S : PreservedBitcodeSymbols)<br>
> >> - CG.addMustPreserveSymbol(S->getName());<br>
> >> + // Likewise for other symbols that must be preserved.<br>
> >> + for (StringRef Name : Config->GCRoots)<br>
> >> + if (isa<DefinedBitcode>(Symtab[Name]->Body))<br>
> >> + CG.addMustPreserveSymbol(Name);<br>
> >><br>
> >> CG.setModule(BitcodeFiles[0]->releaseModule());<br>
> >> for (unsigned I = 1, E = BitcodeFiles.size(); I != E; ++I)<br>
> >><br>
> >> Modified: lld/trunk/COFF/Writer.cpp<br>
> >> URL:<br>
> >> <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_COFF_Writer.cpp-3Frev-3D239005-26r1-3D239004-26r2-3D239005-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=8GlBiuBmAoO-g9xTeNSES6mF01UgMWBpIDuu5p1aGGo&e=" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.cpp?rev=239005&r1=239004&r2=239005&view=diff</a><br>
> >><br>
> >> ==============================================================================<br>
> >> --- lld/trunk/COFF/Writer.cpp (original)<br>
> >> +++ lld/trunk/COFF/Writer.cpp Wed Jun 3 21:12:16 2015<br>
> >> @@ -87,8 +87,8 @@ void OutputSection::writeHeader(uint8_t<br>
> >> }<br>
> >><br>
> >> void Writer::markLive() {<br>
> >> - Entry = cast<Defined>(Symtab->find(Config->EntryName));<br>
> >> - Entry->markLive();<br>
> >> + for (StringRef Name : Config->GCRoots)<br>
> >> + cast<Defined>(Symtab->find(Name))->markLive();<br>
> >> for (Chunk *C : Symtab->getChunks())<br>
> >> if (C->isRoot())<br>
> >> C->markLive();<br>
> >> @@ -291,6 +291,7 @@ void Writer::writeHeader() {<br>
> >> PE->Subsystem = Config->Subsystem;<br>
> >> PE->SizeOfImage = SizeOfImage;<br>
> >> PE->SizeOfHeaders = SizeOfHeaders;<br>
> >> + Defined *Entry = cast<Defined>(Symtab->find(Config->EntryName));<br>
> >> PE->AddressOfEntryPoint = Entry->getRVA();<br>
> >> PE->SizeOfStackReserve = Config->StackReserve;<br>
> >> PE->SizeOfStackCommit = Config->StackCommit;<br>
> >><br>
> >> Modified: lld/trunk/COFF/Writer.h<br>
> >> URL:<br>
> >> <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_COFF_Writer.h-3Frev-3D239005-26r1-3D239004-26r2-3D239005-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=wj6jy1yjkWKWi0aMEqqSeGnI6BUPbP2a9r307wk4DmE&e=" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.h?rev=239005&r1=239004&r2=239005&view=diff</a><br>
> >><br>
> >> ==============================================================================<br>
> >> --- lld/trunk/COFF/Writer.h (original)<br>
> >> +++ lld/trunk/COFF/Writer.h Wed Jun 3 21:12:16 2015<br>
> >> @@ -98,7 +98,6 @@ private:<br>
> >> uint32_t ImportDirectoryTableSize = 0;<br>
> >> uint32_t ImportAddressTableSize = 0;<br>
> >><br>
> >> - Defined *Entry;<br>
> >> uint64_t FileSize;<br>
> >> uint64_t SizeOfImage;<br>
> >> uint64_t SizeOfHeaders;<br>
> >><br>
> >> Modified: lld/trunk/test/COFF/lto.ll<br>
> >> URL:<br>
> >> <a href="https://urldefense.proofpoint.com/v2/url?u=http-3A__llvm.org_viewvc_llvm-2Dproject_lld_trunk_test_COFF_lto.ll-3Frev-3D239005-26r1-3D239004-26r2-3D239005-26view-3Ddiff&d=AwMFaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=mQ4LZ2PUj9hpadE3cDHZnIdEwhEBrbAstXeMaFoB9tg&m=_jfUkfkET7Y_Y_y30Q6Ld0xPReegwPhASPLTKUTAXVc&s=9mL1wSE6MTFe1xVJRdK63fkK0mObP2Q0Bd_5aFxg2cA&e=" target="_blank">http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/lto.ll?rev=239005&r1=239004&r2=239005&view=diff</a><br>
> >><br>
> >> ==============================================================================<br>
> >> --- lld/trunk/test/COFF/lto.ll (original)<br>
> >> +++ lld/trunk/test/COFF/lto.ll Wed Jun 3 21:12:16 2015<br>
> >> @@ -8,10 +8,10 @@<br>
> >> ; RUN: rm -f %T/foo.lib<br>
> >> ; RUN: llvm-ar cru %T/foo.lib %T/foo.obj<br>
> >><br>
> >> -; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /subsystem:console<br>
> >> %T/main.lto.obj %T/foo.lto.obj<br>
> >> +; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /include:f2<br>
> >> /subsystem:console %T/main.lto.obj %T/foo.lto.obj<br>
> >> ; RUN: llvm-readobj -file-headers %T/main.exe | FileCheck<br>
> >> -check-prefix=HEADERS-11 %s<br>
> >> ; RUN: llvm-objdump -d %T/main.exe | FileCheck -check-prefix=TEXT-11 %s<br>
> >> -; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /subsystem:console<br>
> >> %T/main.lto.obj %T/foo.lto.lib<br>
> >> +; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /include:f2<br>
> >> /subsystem:console %T/main.lto.obj %T/foo.lto.lib<br>
> >> ; RUN: llvm-readobj -file-headers %T/main.exe | FileCheck<br>
> >> -check-prefix=HEADERS-11 %s<br>
> >> ; RUN: llvm-objdump -d %T/main.exe | FileCheck -check-prefix=TEXT-11 %s<br>
> >><br>
> >> @@ -34,6 +34,21 @@<br>
> >> ; TEXT-11-NEXT: .text:<br>
> >> ; TEXT-11-NEXT: xorl %eax, %eax<br>
> >> ; TEXT-11-NEXT: retq<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: int3<br>
> >> +; TEXT-11-NEXT: movl $2, %eax<br>
> >> +; TEXT-11-NEXT: retq<br>
> >><br>
> >> ; HEADERS-01: AddressOfEntryPoint: 0x1000<br>
> >> ; TEXT-01: Disassembly of section .text:<br>
> >> @@ -79,3 +94,13 @@ define i32 @main() {<br>
> >> }<br>
> >><br>
> >> declare void @foo()<br>
> >> +<br>
> >> +$f1 = comdat any<br>
> >> +define i32 @f1() comdat($f1) {<br>
> >> + ret i32 1<br>
> >> +}<br>
> >> +<br>
> >> +$f2 = comdat any<br>
> >> +define i32 @f2() comdat($f2) {<br>
> >> + ret i32 2<br>
> >> +}<br>
> >><br>
> >><br>
> >> _______________________________________________<br>
> >> llvm-commits mailing list<br>
> >> <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
> >> <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits</a><br>
> >><br>
> ><br>
<br>
> _______________________________________________<br>
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> <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
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<br>
<br>
</div></div><span class="HOEnZb"><font color="#888888">--<br>
Peter<br>
</font></span></blockquote></div><br></div>