Author: steven_wu Date: Mon May 16 13:54:58 2016 New Revision: 269679 URL: http://llvm.org/viewvc/llvm-project?rev=269679&view=rev Log: Change embed-bitcode linkage type
Embedded bitcode should have private linkage instead of appending or external. Otherwise, it will cause link failure due to duplicated symbols. Also add llvm.embedded.module and llvm.cmdline to llvm.compiler.used so they don't get optimized out. rdar://problem/21555860 Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp cfe/trunk/test/Frontend/embed-bitcode.ll Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/BackendUtil.cpp?rev=269679&r1=269678&r2=269679&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/BackendUtil.cpp (original) +++ cfe/trunk/lib/CodeGen/BackendUtil.cpp Mon May 16 13:54:58 2016 @@ -797,6 +797,20 @@ void clang::EmbedBitcode(llvm::Module *M if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Off) return; + // Save llvm.compiler.used and remote it. + SmallVector<Constant*, 2> UsedArray; + SmallSet<GlobalValue*, 4> UsedGlobals; + Type *UsedElementType = Type::getInt8Ty(M->getContext())->getPointerTo(0); + GlobalVariable *Used = collectUsedGlobalVariables(*M, UsedGlobals, true); + for (auto *GV : UsedGlobals) { + if (GV->getName() != "llvm.embedded.module" && + GV->getName() != "llvm.cmdline") + UsedArray.push_back( + ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType)); + } + if (Used) + Used->eraseFromParent(); + // Embed the bitcode for the llvm module. std::string Data; ArrayRef<uint8_t> ModuleData; @@ -820,38 +834,53 @@ void clang::EmbedBitcode(llvm::Module *M } llvm::Constant *ModuleConstant = llvm::ConstantDataArray::get(M->getContext(), ModuleData); - // Use Appending linkage so it doesn't get optimized out. llvm::GlobalVariable *GV = new llvm::GlobalVariable( - *M, ModuleConstant->getType(), true, llvm::GlobalValue::AppendingLinkage, + *M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage, ModuleConstant); GV->setSection(getSectionNameForBitcode(T)); + UsedArray.push_back( + ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType)); if (llvm::GlobalVariable *Old = - M->getGlobalVariable("llvm.embedded.module")) { - assert(Old->use_empty() && "llvm.embedded.module must have no uses"); + M->getGlobalVariable("llvm.embedded.module", true)) { + assert(Old->hasOneUse() && + "llvm.embedded.module can only be used once in llvm.compiler.used"); GV->takeName(Old); Old->eraseFromParent(); } else { GV->setName("llvm.embedded.module"); } - // Return if only bitcode needs to be embedded. - if (CGOpts.getEmbedBitcode() == CodeGenOptions::Embed_Bitcode) + // Skip if only bitcode needs to be embedded. + if (CGOpts.getEmbedBitcode() != CodeGenOptions::Embed_Bitcode) { + // Embed command-line options. + ArrayRef<uint8_t> CmdData((uint8_t*)CGOpts.CmdArgs.data(), + CGOpts.CmdArgs.size()); + llvm::Constant *CmdConstant = + llvm::ConstantDataArray::get(M->getContext(), CmdData); + GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true, + llvm::GlobalValue::PrivateLinkage, + CmdConstant); + GV->setSection(getSectionNameForCommandline(T)); + UsedArray.push_back( + ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType)); + if (llvm::GlobalVariable *Old = + M->getGlobalVariable("llvm.cmdline", true)) { + assert(Old->hasOneUse() && + "llvm.cmdline can only be used once in llvm.compiler.used"); + GV->takeName(Old); + Old->eraseFromParent(); + } else { + GV->setName("llvm.cmdline"); + } + } + + if (UsedArray.empty()) return; - // Embed command-line options. - ArrayRef<uint8_t> CmdData((uint8_t*)CGOpts.CmdArgs.data(), - CGOpts.CmdArgs.size()); - llvm::Constant *CmdConstant = - llvm::ConstantDataArray::get(M->getContext(), CmdData); - GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true, - llvm::GlobalValue::AppendingLinkage, - CmdConstant); - GV->setSection(getSectionNameForCommandline(T)); - if (llvm::GlobalVariable *Old = M->getGlobalVariable("llvm.cmdline")) { - assert(Old->use_empty() && "llvm.cmdline must have no uses"); - GV->takeName(Old); - Old->eraseFromParent(); - } else { - GV->setName("llvm.cmdline"); - } + // Recreate llvm.compiler.used. + ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size()); + auto *NewUsed = new GlobalVariable( + *M, ATy, false, llvm::GlobalValue::AppendingLinkage, + llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used"); + NewUsed->setSection("llvm.metadata"); } Modified: cfe/trunk/test/Frontend/embed-bitcode.ll URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Frontend/embed-bitcode.ll?rev=269679&r1=269678&r2=269679&view=diff ============================================================================== --- cfe/trunk/test/Frontend/embed-bitcode.ll (original) +++ cfe/trunk/test/Frontend/embed-bitcode.ll Mon May 16 13:54:58 2016 @@ -31,10 +31,10 @@ ; RUN: -fembed-bitcode=all -x ir - -o /dev/null ; check the magic number of bitcode at the beginning of the string -; CHECK: @llvm.embedded.module +; CHECK: @llvm.embedded.module = private constant ; CHECK: c"\DE\C0\17\0B ; CHECK: section "__LLVM,__bitcode" -; CHECK: @llvm.cmdline +; CHECK: @llvm.cmdline = private constant ; CHECK: section "__LLVM,__cmdline" ; CHECK-ELF: @llvm.embedded.module @@ -42,10 +42,10 @@ ; CHECK-ELF: @llvm.cmdline ; CHECK-ELF: section ".llvmcmd" -; CHECK-ONLY-BITCODE: @llvm.embedded.module +; CHECK-ONLY-BITCODE: @llvm.embedded.module = private constant ; CHECK-ONLY-BITCODE: c"\DE\C0\17\0B ; CHECK-ONLY-BITCODE: section "__LLVM,__bitcode" -; CHECK-ONLY-BITCODE-NOT: @llvm.cmdline +; CHECK-ONLY-BITCODE-NOT: @llvm.cmdline = private constant ; CHECK-ONLY-BITCODE-NOT: section "__LLVM,__cmdline" ; CHECK-MARKER: @llvm.embedded.module _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits