diff options
Diffstat (limited to 'lib/LTO/LTOBackend.cpp')
-rw-r--r-- | lib/LTO/LTOBackend.cpp | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/lib/LTO/LTOBackend.cpp b/lib/LTO/LTOBackend.cpp index 28b55a000af..76b20b5130f 100644 --- a/lib/LTO/LTOBackend.cpp +++ b/lib/LTO/LTOBackend.cpp @@ -25,6 +25,7 @@ #include "llvm/IR/PassManager.h" #include "llvm/IR/Verifier.h" #include "llvm/LTO/LTO.h" +#include "llvm/LTO/legacy/UpdateCompilerUsed.h" #include "llvm/MC/SubtargetFeature.h" #include "llvm/Passes/PassBuilder.h" #include "llvm/Support/Error.h" @@ -275,6 +276,19 @@ Expected<const Target *> initAndLookupTarget(Config &C, Module &Mod) { } +static void handleAsmUndefinedRefs(Module &Mod, TargetMachine &TM) { + // Collect the list of undefined symbols used in asm and update + // llvm.compiler.used to prevent optimization to drop these from the output. + StringSet<> AsmUndefinedRefs; + object::IRObjectFile::CollectAsmUndefinedRefs( + Triple(Mod.getTargetTriple()), Mod.getModuleInlineAsm(), + [&AsmUndefinedRefs](StringRef Name, object::BasicSymbolRef::Flags Flags) { + if (Flags & object::BasicSymbolRef::SF_Undefined) + AsmUndefinedRefs.insert(Name); + }); + updateCompilerUsed(Mod, TM, AsmUndefinedRefs); +} + Error lto::backend(Config &C, AddOutputFn AddOutput, unsigned ParallelCodeGenParallelismLevel, std::unique_ptr<Module> Mod) { @@ -285,6 +299,8 @@ Error lto::backend(Config &C, AddOutputFn AddOutput, std::unique_ptr<TargetMachine> TM = createTargetMachine(C, Mod->getTargetTriple(), *TOrErr); + handleAsmUndefinedRefs(*Mod, *TM); + if (!C.CodeGenOnly) if (!opt(C, TM.get(), 0, *Mod, /*IsThinLto=*/false)) return Error(); @@ -310,6 +326,8 @@ Error lto::thinBackend(Config &Conf, unsigned Task, AddOutputFn AddOutput, std::unique_ptr<TargetMachine> TM = createTargetMachine(Conf, Mod.getTargetTriple(), *TOrErr); + handleAsmUndefinedRefs(Mod, *TM); + if (Conf.CodeGenOnly) { codegen(Conf, TM.get(), AddOutput, Task, Mod); return Error(); |