diff options
Diffstat (limited to 'lib/Target/TargetMachine.cpp')
| -rw-r--r-- | lib/Target/TargetMachine.cpp | 47 |
1 files changed, 32 insertions, 15 deletions
diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp index c4c0dd22ee0c..092f5ea4104b 100644 --- a/lib/Target/TargetMachine.cpp +++ b/lib/Target/TargetMachine.cpp @@ -13,8 +13,6 @@ #include "llvm/Target/TargetMachine.h" #include "llvm/Analysis/TargetTransformInfo.h" -#include "llvm/CodeGen/TargetLoweringObjectFile.h" -#include "llvm/CodeGen/TargetSubtargetInfo.h" #include "llvm/IR/Function.h" #include "llvm/IR/GlobalAlias.h" #include "llvm/IR/GlobalValue.h" @@ -27,6 +25,7 @@ #include "llvm/MC/MCSectionMachO.h" #include "llvm/MC/MCTargetOptions.h" #include "llvm/MC/SectionKind.h" +#include "llvm/Target/TargetLoweringObjectFile.h" using namespace llvm; //--------------------------------------------------------------------------- @@ -52,7 +51,7 @@ bool TargetMachine::isPositionIndependent() const { return getRelocationModel() == Reloc::PIC_; } -/// \brief Reset the target options based on the function's attributes. +/// Reset the target options based on the function's attributes. // FIXME: This function needs to go away for a number of reasons: // a) global state on the TargetMachine is terrible in general, // b) these target options should be passed only on the function @@ -116,12 +115,24 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M, if (GV && GV->isDSOLocal()) return true; - // According to the llvm language reference, we should be able to just return - // false in here if we have a GV, as we know it is dso_preemptable. - // At this point in time, the various IR producers have not been transitioned - // to always produce a dso_local when it is possible to do so. As a result we - // still have some pre-dso_local logic in here to improve the quality of the - // generated code: + // If we are not supossed to use a PLT, we cannot assume that intrinsics are + // local since the linker can convert some direct access to access via plt. + if (M.getRtLibUseGOT() && !GV) + return false; + + // According to the llvm language reference, we should be able to + // just return false in here if we have a GV, as we know it is + // dso_preemptable. At this point in time, the various IR producers + // have not been transitioned to always produce a dso_local when it + // is possible to do so. + // In the case of intrinsics, GV is null and there is nowhere to put + // dso_local. Returning false for those will produce worse code in some + // architectures. For example, on x86 the caller has to set ebx before calling + // a plt. + // As a result we still have some logic in here to improve the quality of the + // generated code. + // FIXME: Add a module level metadata for whether intrinsics should be assumed + // local. Reloc::Model RM = getRelocationModel(); const Triple &TT = getTargetTriple(); @@ -131,7 +142,7 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M, return false; // Every other GV is local on COFF. - // Make an exception for windows OS in the triple: Some firmwares builds use + // Make an exception for windows OS in the triple: Some firmware builds use // *-win32-macho triples. This (accidentally?) produced windows relocations // without GOT tables in older clang versions; Keep this behaviour. if (TT.isOSBinFormatCOFF() || (TT.isOSWindows() && TT.isOSBinFormatMachO())) @@ -141,12 +152,10 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M, // 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. - // FIXME: this is probably not ELF specific. - if (GV && isPositionIndependent() && TT.isOSBinFormatELF() && - GV->hasExternalWeakLinkage()) + if (GV && isPositionIndependent() && GV->hasExternalWeakLinkage()) return false; - if (GV && (GV->hasLocalLinkage() || !GV->hasDefaultVisibility())) + if (GV && !GV->hasDefaultVisibility()) return true; if (TT.isOSBinFormatMachO()) { @@ -174,7 +183,7 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M, bool IsTLS = GV && GV->isThreadLocal(); bool IsAccessViaCopyRelocs = - Options.MCOptions.MCPIECopyRelocations && GV && isa<GlobalVariable>(GV); + GV && Options.MCOptions.MCPIECopyRelocations && isa<GlobalVariable>(GV); Triple::ArchType Arch = TT.getArch(); bool IsPPC = Arch == Triple::ppc || Arch == Triple::ppc64 || Arch == Triple::ppc64le; @@ -187,6 +196,14 @@ bool TargetMachine::shouldAssumeDSOLocal(const Module &M, return false; } +bool TargetMachine::useEmulatedTLS() const { + // Returns Options.EmulatedTLS if the -emulated-tls or -no-emulated-tls + // was specified explicitly; otherwise uses target triple to decide default. + if (Options.ExplicitEmulatedTLS) + return Options.EmulatedTLS; + return getTargetTriple().hasDefaultEmulatedTLS(); +} + TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const { bool IsPIE = GV->getParent()->getPIELevel() != PIELevel::Default; Reloc::Model RM = getRelocationModel(); |