diff options
author | Davide Italiano <davide@freebsd.org> | 2016-09-16 16:05:25 +0000 |
---|---|---|
committer | Davide Italiano <davide@freebsd.org> | 2016-09-16 16:05:25 +0000 |
commit | 3284f278cd4c93188a608ab813094f02f4f8b717 (patch) | |
tree | 699970416cfb26dc18e5cdaa3e0f8cb6cfdff99d /lib | |
parent | c49f5e8a930294c02c94731950b6e7e2c94160e5 (diff) |
[LTO] Prevent asm references to be dropped from the output.
Differential Revision: https://reviews.llvm.org/D24617
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281741 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-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(); |