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
llvm-svn: 269679
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index bffa621..5a1db6c 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -797,6 +797,20 @@
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 @@
}
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");
}