From 432a587cf00b3ecb552750f0f4dbd830e18f500c Mon Sep 17 00:00:00 2001 From: Rafael Espindola Date: Wed, 24 Jan 2018 02:11:18 +0000 Subject: Don't assume a null GV is local for ELF and MachO. This is already a simplification, and should help with avoiding a plt reference when calling an intrinsic with -fno-plt. With this change we return false for null GVs, so the caller only needs to check the new metadata to decide if it should use foo@plt or *foo@got. llvm-svn: 323297 --- llvm/lib/Target/TargetMachine.cpp | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'llvm/lib') diff --git a/llvm/lib/Target/TargetMachine.cpp b/llvm/lib/Target/TargetMachine.cpp index ee5b010ecf2..76ec541f8b6 100644 --- a/llvm/lib/Target/TargetMachine.cpp +++ b/llvm/lib/Target/TargetMachine.cpp @@ -137,20 +137,27 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M, if (TT.isOSBinFormatCOFF() || (TT.isOSWindows() && TT.isOSBinFormatMachO())) return true; + // If GV is null we know that this is a call to an intrinsic. For ELF and + // MachO we don't need to assume those are local since the liker can trivially + // convert a call to a PLT to a direct call if the target (in the runtime + // library) turns out to be local. + if (!GV) + return false; + // Most PIC code sequences that assume that a symbol is local cannot // produce a 0 if it turns out the symbol is undefined. While this // is ABI and relocation depended, it seems worth it to handle it // here. - if (GV && isPositionIndependent() && GV->hasExternalWeakLinkage()) + if (isPositionIndependent() && GV->hasExternalWeakLinkage()) return false; - if (GV && !GV->hasDefaultVisibility()) + if (!GV->hasDefaultVisibility()) return true; if (TT.isOSBinFormatMachO()) { if (RM == Reloc::Static) return true; - return GV && GV->isStrongDefinitionForLinker(); + return GV->isStrongDefinitionForLinker(); } assert(TT.isOSBinFormatELF()); @@ -160,19 +167,19 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M, RM == Reloc::Static || M.getPIELevel() != PIELevel::Default; if (IsExecutable) { // If the symbol is defined, it cannot be preempted. - if (GV && !GV->isDeclarationForLinker()) + if (!GV->isDeclarationForLinker()) return true; // A symbol marked nonlazybind should not be accessed with a plt. If the // symbol turns out to be external, the linker will convert a direct // access to an access via the plt, so don't assume it is local. - const Function *F = dyn_cast_or_null(GV); + const Function *F = dyn_cast(GV); if (F && F->hasFnAttribute(Attribute::NonLazyBind)) return false; - bool IsTLS = GV && GV->isThreadLocal(); + bool IsTLS = GV->isThreadLocal(); bool IsAccessViaCopyRelocs = - Options.MCOptions.MCPIECopyRelocations && GV && isa(GV); + Options.MCOptions.MCPIECopyRelocations && isa(GV); Triple::ArchType Arch = TT.getArch(); bool IsPPC = Arch == Triple::ppc || Arch == Triple::ppc64 || Arch == Triple::ppc64le; -- cgit v1.2.3