[lld] r239005 - COFF: /include'd symbols must be preserved.
David Majnemer
david.majnemer at gmail.com
Wed Jun 3 20:40:55 PDT 2015
Do you already do the same for exported symbols?
On Wednesday, June 3, 2015, Rui Ueyama <ruiu at google.com> wrote:
> Author: ruiu
> Date: Wed Jun 3 21:12:16 2015
> New Revision: 239005
>
> URL: http://llvm.org/viewvc/llvm-project?rev=239005&view=rev
> Log:
> COFF: /include'd symbols must be preserved.
>
> Not only entry point symbol but also symbols specified by /include
> option must be preserved, as they will never be dead-stripped.
>
> http://reviews.llvm.org/D10220
>
> Modified:
> lld/trunk/COFF/Config.h
> lld/trunk/COFF/Driver.cpp
> lld/trunk/COFF/SymbolTable.cpp
> lld/trunk/COFF/Writer.cpp
> lld/trunk/COFF/Writer.h
> lld/trunk/test/COFF/lto.ll
>
> Modified: lld/trunk/COFF/Config.h
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Config.h?rev=239005&r1=239004&r2=239005&view=diff
>
> ==============================================================================
> --- lld/trunk/COFF/Config.h (original)
> +++ lld/trunk/COFF/Config.h Wed Jun 3 21:12:16 2015
> @@ -27,7 +27,10 @@ public:
> llvm::COFF::MachineTypes MachineType =
> llvm::COFF::IMAGE_FILE_MACHINE_AMD64;
> bool Verbose = false;
> WindowsSubsystem Subsystem = llvm::COFF::IMAGE_SUBSYSTEM_UNKNOWN;
> - std::string EntryName;
> + StringRef EntryName;
> +
> + // Symbols in this set are considered as live by the garbage collector.
> + std::set<StringRef> GCRoots;
>
> std::set<StringRef> NoDefaultLibs;
> bool NoDefaultLibAll = false;
>
> Modified: lld/trunk/COFF/Driver.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Driver.cpp?rev=239005&r1=239004&r2=239005&view=diff
>
> ==============================================================================
> --- lld/trunk/COFF/Driver.cpp (original)
> +++ lld/trunk/COFF/Driver.cpp Wed Jun 3 21:12:16 2015
> @@ -312,8 +312,11 @@ bool LinkerDriver::link(int Argc, const
>
> // Add undefined symbols given via the command line.
> // (/include is equivalent to Unix linker's -u option.)
> - for (auto *Arg : Args->filtered(OPT_incl))
> - Symtab.addUndefined(Arg->getValue());
> + for (auto *Arg : Args->filtered(OPT_incl)) {
> + StringRef Sym = Arg->getValue();
> + Symtab.addUndefined(Sym);
> + Config->GCRoots.insert(Sym);
> + }
>
> // Parse all input files and put all symbols to the symbol table.
> // The symbol table will take care of name resolution.
> @@ -362,11 +365,14 @@ bool LinkerDriver::link(int Argc, const
> }
> Config->EntryName = EntryOrErr.get();
> }
> + Config->GCRoots.insert(Config->EntryName);
>
> // Make sure we have resolved all symbols.
> if (Symtab.reportRemainingUndefines())
> return false;
>
> + // Do LTO by compiling bitcode input files to a native COFF file
> + // then link that file.
> if (auto EC = Symtab.addCombinedLTOObject()) {
> llvm::errs() << EC.message() << "\n";
> return false;
>
> Modified: lld/trunk/COFF/SymbolTable.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/SymbolTable.cpp?rev=239005&r1=239004&r2=239005&view=diff
>
> ==============================================================================
> --- lld/trunk/COFF/SymbolTable.cpp (original)
> +++ lld/trunk/COFF/SymbolTable.cpp Wed Jun 3 21:12:16 2015
> @@ -227,20 +227,17 @@ std::error_code SymbolTable::addCombined
> return std::error_code();
>
> llvm::LTOCodeGenerator CG;
> - std::set<DefinedBitcode *> PreservedBitcodeSymbols;
>
> // All symbols referenced by non-bitcode objects must be preserved.
> for (std::unique_ptr<ObjectFile> &File : ObjectFiles)
> for (SymbolBody *Body : File->getSymbols())
> if (auto *S = dyn_cast<DefinedBitcode>(Body->getReplacement()))
> - PreservedBitcodeSymbols.insert(S);
> + CG.addMustPreserveSymbol(S->getName());
>
> - // Likewise for the linker-generated reference to the entry point.
> - if (auto *S = dyn_cast<DefinedBitcode>(Symtab[Config->EntryName]->Body))
> - PreservedBitcodeSymbols.insert(S);
> -
> - for (DefinedBitcode *S : PreservedBitcodeSymbols)
> - CG.addMustPreserveSymbol(S->getName());
> + // Likewise for other symbols that must be preserved.
> + for (StringRef Name : Config->GCRoots)
> + if (isa<DefinedBitcode>(Symtab[Name]->Body))
> + CG.addMustPreserveSymbol(Name);
>
> CG.setModule(BitcodeFiles[0]->releaseModule());
> for (unsigned I = 1, E = BitcodeFiles.size(); I != E; ++I)
>
> Modified: lld/trunk/COFF/Writer.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.cpp?rev=239005&r1=239004&r2=239005&view=diff
>
> ==============================================================================
> --- lld/trunk/COFF/Writer.cpp (original)
> +++ lld/trunk/COFF/Writer.cpp Wed Jun 3 21:12:16 2015
> @@ -87,8 +87,8 @@ void OutputSection::writeHeader(uint8_t
> }
>
> void Writer::markLive() {
> - Entry = cast<Defined>(Symtab->find(Config->EntryName));
> - Entry->markLive();
> + for (StringRef Name : Config->GCRoots)
> + cast<Defined>(Symtab->find(Name))->markLive();
> for (Chunk *C : Symtab->getChunks())
> if (C->isRoot())
> C->markLive();
> @@ -291,6 +291,7 @@ void Writer::writeHeader() {
> PE->Subsystem = Config->Subsystem;
> PE->SizeOfImage = SizeOfImage;
> PE->SizeOfHeaders = SizeOfHeaders;
> + Defined *Entry = cast<Defined>(Symtab->find(Config->EntryName));
> PE->AddressOfEntryPoint = Entry->getRVA();
> PE->SizeOfStackReserve = Config->StackReserve;
> PE->SizeOfStackCommit = Config->StackCommit;
>
> Modified: lld/trunk/COFF/Writer.h
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Writer.h?rev=239005&r1=239004&r2=239005&view=diff
>
> ==============================================================================
> --- lld/trunk/COFF/Writer.h (original)
> +++ lld/trunk/COFF/Writer.h Wed Jun 3 21:12:16 2015
> @@ -98,7 +98,6 @@ private:
> uint32_t ImportDirectoryTableSize = 0;
> uint32_t ImportAddressTableSize = 0;
>
> - Defined *Entry;
> uint64_t FileSize;
> uint64_t SizeOfImage;
> uint64_t SizeOfHeaders;
>
> Modified: lld/trunk/test/COFF/lto.ll
> URL:
> http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/lto.ll?rev=239005&r1=239004&r2=239005&view=diff
>
> ==============================================================================
> --- lld/trunk/test/COFF/lto.ll (original)
> +++ lld/trunk/test/COFF/lto.ll Wed Jun 3 21:12:16 2015
> @@ -8,10 +8,10 @@
> ; RUN: rm -f %T/foo.lib
> ; RUN: llvm-ar cru %T/foo.lib %T/foo.obj
>
> -; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /subsystem:console
> %T/main.lto.obj %T/foo.lto.obj
> +; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /include:f2
> /subsystem:console %T/main.lto.obj %T/foo.lto.obj
> ; RUN: llvm-readobj -file-headers %T/main.exe | FileCheck
> -check-prefix=HEADERS-11 %s
> ; RUN: llvm-objdump -d %T/main.exe | FileCheck -check-prefix=TEXT-11 %s
> -; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /subsystem:console
> %T/main.lto.obj %T/foo.lto.lib
> +; RUN: lld -flavor link2 /out:%T/main.exe /entry:main /include:f2
> /subsystem:console %T/main.lto.obj %T/foo.lto.lib
> ; RUN: llvm-readobj -file-headers %T/main.exe | FileCheck
> -check-prefix=HEADERS-11 %s
> ; RUN: llvm-objdump -d %T/main.exe | FileCheck -check-prefix=TEXT-11 %s
>
> @@ -34,6 +34,21 @@
> ; TEXT-11-NEXT: .text:
> ; TEXT-11-NEXT: xorl %eax, %eax
> ; TEXT-11-NEXT: retq
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: int3
> +; TEXT-11-NEXT: movl $2, %eax
> +; TEXT-11-NEXT: retq
>
> ; HEADERS-01: AddressOfEntryPoint: 0x1000
> ; TEXT-01: Disassembly of section .text:
> @@ -79,3 +94,13 @@ define i32 @main() {
> }
>
> declare void @foo()
> +
> +$f1 = comdat any
> +define i32 @f1() comdat($f1) {
> + ret i32 1
> +}
> +
> +$f2 = comdat any
> +define i32 @f2() comdat($f2) {
> + ret i32 2
> +}
>
>
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