diff options
| -rw-r--r-- | llvm/lib/Object/ArchiveWriter.cpp | 39 | ||||
| -rw-r--r-- | llvm/test/Object/archive-malformed-object.test | 26 |
2 files changed, 56 insertions, 9 deletions
diff --git a/llvm/lib/Object/ArchiveWriter.cpp b/llvm/lib/Object/ArchiveWriter.cpp index 913b74c..c6d443f 100644 --- a/llvm/lib/Object/ArchiveWriter.cpp +++ b/llvm/lib/Object/ArchiveWriter.cpp @@ -482,7 +482,8 @@ static uint64_t computeHeadersSize(object::Archive::Kind Kind, } static Expected<std::unique_ptr<SymbolicFile>> -getSymbolicFile(MemoryBufferRef Buf, LLVMContext &Context) { +getSymbolicFile(MemoryBufferRef Buf, LLVMContext &Context, + object::Archive::Kind Kind) { const file_magic Type = identify_magic(Buf.getBuffer()); // Don't attempt to read non-symbolic file types. if (!object::SymbolicFile::isSymbolicFile(Type, &Context)) @@ -490,8 +491,38 @@ getSymbolicFile(MemoryBufferRef Buf, LLVMContext &Context) { if (Type == file_magic::bitcode) { auto ObjOrErr = object::SymbolicFile::createSymbolicFile( Buf, file_magic::bitcode, &Context); - if (!ObjOrErr) - return ObjOrErr.takeError(); + // An error reading a bitcode file most likely indicates that the file + // was created by a compiler from the future. Normally we don't try to + // implement forwards compatibility for bitcode files, but when creating an + // archive we can implement best-effort forwards compatibility by treating + // the file as a blob and not creating symbol index entries for it. lld and + // mold ignore the archive symbol index, so provided that you use one of + // these linkers, LTO will work as long as lld or the gold plugin is newer + // than the compiler. We only ignore errors if the archive format is one + // that is supported by a linker that is known to ignore the index, + // otherwise there's no chance of this working so we may as well error out. + // We print a warning on read failure so that users of linkers that rely on + // the symbol index can diagnose the issue. + // + // This is the same behavior as GNU ar when the linker plugin returns an + // error when reading the input file. If the bitcode file is actually + // malformed, it will be diagnosed at link time. + if (!ObjOrErr) { + switch (Kind) { + case object::Archive::K_BSD: + case object::Archive::K_GNU: + case object::Archive::K_GNU64: + llvm::logAllUnhandledErrors(ObjOrErr.takeError(), llvm::errs(), + "warning: " + Buf.getBufferIdentifier() + + ": "); + return nullptr; + case object::Archive::K_AIXBIG: + case object::Archive::K_COFF: + case object::Archive::K_DARWIN: + case object::Archive::K_DARWIN64: + return ObjOrErr.takeError(); + } + } return std::move(*ObjOrErr); } else { auto ObjOrErr = object::SymbolicFile::createSymbolicFile(Buf); @@ -820,7 +851,7 @@ computeMemberData(raw_ostream &StringTable, raw_ostream &SymNames, if (NeedSymbols != SymtabWritingMode::NoSymtab || isAIXBigArchive(Kind)) { for (const NewArchiveMember &M : NewMembers) { Expected<std::unique_ptr<SymbolicFile>> SymFileOrErr = - getSymbolicFile(M.Buf->getMemBufferRef(), Context); + getSymbolicFile(M.Buf->getMemBufferRef(), Context, Kind); if (!SymFileOrErr) return createFileError(M.MemberName, SymFileOrErr.takeError()); SymFiles.push_back(std::move(*SymFileOrErr)); diff --git a/llvm/test/Object/archive-malformed-object.test b/llvm/test/Object/archive-malformed-object.test index a927629..7492dc5 100644 --- a/llvm/test/Object/archive-malformed-object.test +++ b/llvm/test/Object/archive-malformed-object.test @@ -1,5 +1,6 @@ ## Show that the archive library emits error messages when adding malformed -## objects. +## object files and skips symbol tables for "malformed" bitcode files, which +## are assumed to be bitcode files generated by compilers from the future. # RUN: rm -rf %t.dir # RUN: split-file %s %t.dir @@ -9,19 +10,28 @@ # RUN: llvm-as input.ll -o input.bc # RUN: cp input.bc good.bc # RUN: %python -c "with open('input.bc', 'a') as f: f.truncate(10)" -# RUN: not llvm-ar rc bad.a input.bc 2>&1 | FileCheck %s --check-prefix=ERR1 +# RUN: llvm-ar rc bad.a input.bc 2>&1 | FileCheck %s --check-prefix=WARN1 + +# llvm-nm will fail when it tries to read the malformed bitcode file, but +# it's supposed to print the archive map first, which in this case it +# won't because there won't be one. +# RUN: not llvm-nm --print-armap bad.a | count 0 ## Malformed bitcode object is the last file member of archive if the symbol table is required. # RUN: rm -rf bad.a -# RUN: not llvm-ar rc bad.a good.bc input.bc 2>&1 | FileCheck %s --check-prefix=ERR1 +# RUN: llvm-ar rc bad.a good.bc input.bc 2>&1 | FileCheck %s --check-prefix=WARN1 +# RUN: not llvm-nm --print-armap bad.a | FileCheck %s --check-prefix=ARMAP ## Malformed bitcode object if the symbol table is not required for big archive. +## For big archives we print an error instead of a warning because the AIX linker +## presumably requires the index. # RUN: rm -rf bad.a # RUN: not llvm-ar --format=bigarchive rcS bad.a input.bc 2>&1 | FileCheck %s --check-prefix=ERR1 # RUN: rm -rf bad.a # RUN: not llvm-ar --format=bigarchive rcS bad.a good.bc input.bc 2>&1 | FileCheck %s --check-prefix=ERR1 # ERR1: error: bad.a: 'input.bc': Invalid bitcode signature +# WARN1: warning: input.bc: Invalid bitcode signature ## Non-bitcode malformed file. # RUN: yaml2obj input.yaml -o input.o @@ -29,17 +39,23 @@ # ERR2: error: bad.a: 'input.o': section header table goes past the end of the file: e_shoff = 0x9999 -## Don't emit an error if the symbol table is not required for formats other than the big archive format. -# RUN: llvm-ar --format=gnu rcS good.a input.o input.bc +## Don't emit an error or warning if the symbol table is not required for formats other than the big archive format. +# RUN: llvm-ar --format=gnu rcS good.a input.o input.bc 2>&1 | count 0 # RUN: llvm-ar t good.a | FileCheck %s --check-prefix=CONTENTS # CONTENTS: input.o # CONTENTS-NEXT: input.bc +# ARMAP: Archive map +# ARMAP-NEXT: foo in good.bc +# ARMAP-EMPTY: + #--- input.ll target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128" target triple = "x86_64-pc-linux" +@foo = global i32 1 + #--- input.yaml --- !ELF FileHeader: |