llvm-6502/lib/Target/TargetMachine.cpp
Hans Wennborg ce718ff9f4 Extend the IL for selecting TLS models (PR9788)
This allows the user/front-end to specify a model that is better
than what LLVM would choose by default. For example, a variable
might be declared as

  @x = thread_local(initialexec) global i32 42

if it will not be used in a shared library that is dlopen'ed.

If the specified model isn't supported by the target, or if LLVM can
make a better choice, a different model may be used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159077 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-23 11:37:03 +00:00

165 lines
4.8 KiB
C++

//===-- TargetMachine.cpp - General Target Information ---------------------==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file describes the general parts of a Target machine.
//
//===----------------------------------------------------------------------===//
#include "llvm/GlobalAlias.h"
#include "llvm/GlobalValue.h"
#include "llvm/GlobalVariable.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCCodeGenInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
//---------------------------------------------------------------------------
// Command-line options that tend to be useful on more than one back-end.
//
namespace llvm {
bool HasDivModLibcall;
bool AsmVerbosityDefault(false);
}
static cl::opt<bool>
DataSections("fdata-sections",
cl::desc("Emit data into separate sections"),
cl::init(false));
static cl::opt<bool>
FunctionSections("ffunction-sections",
cl::desc("Emit functions into separate sections"),
cl::init(false));
//---------------------------------------------------------------------------
// TargetMachine Class
//
TargetMachine::TargetMachine(const Target &T,
StringRef TT, StringRef CPU, StringRef FS,
const TargetOptions &Options)
: TheTarget(T), TargetTriple(TT), TargetCPU(CPU), TargetFS(FS),
CodeGenInfo(0), AsmInfo(0),
MCRelaxAll(false),
MCNoExecStack(false),
MCSaveTempLabels(false),
MCUseLoc(true),
MCUseCFI(true),
MCUseDwarfDirectory(false),
Options(Options) {
}
TargetMachine::~TargetMachine() {
delete CodeGenInfo;
delete AsmInfo;
}
/// getRelocationModel - Returns the code generation relocation model. The
/// choices are static, PIC, and dynamic-no-pic, and target default.
Reloc::Model TargetMachine::getRelocationModel() const {
if (!CodeGenInfo)
return Reloc::Default;
return CodeGenInfo->getRelocationModel();
}
/// getCodeModel - Returns the code model. The choices are small, kernel,
/// medium, large, and target default.
CodeModel::Model TargetMachine::getCodeModel() const {
if (!CodeGenInfo)
return CodeModel::Default;
return CodeGenInfo->getCodeModel();
}
/// Get the IR-specified TLS model for Var.
static TLSModel::Model getSelectedTLSModel(const GlobalVariable *Var) {
switch (Var->getThreadLocalMode()) {
case GlobalVariable::NotThreadLocal:
llvm_unreachable("getSelectedTLSModel for non-TLS variable");
break;
case GlobalVariable::GeneralDynamicTLSModel:
return TLSModel::GeneralDynamic;
case GlobalVariable::LocalDynamicTLSModel:
return TLSModel::LocalDynamic;
case GlobalVariable::InitialExecTLSModel:
return TLSModel::InitialExec;
case GlobalVariable::LocalExecTLSModel:
return TLSModel::LocalExec;
}
llvm_unreachable("invalid TLS model");
}
TLSModel::Model TargetMachine::getTLSModel(const GlobalValue *GV) const {
// If GV is an alias then use the aliasee for determining
// thread-localness.
if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
GV = GA->resolveAliasedGlobal(false);
const GlobalVariable *Var = cast<GlobalVariable>(GV);
bool isLocal = Var->hasLocalLinkage();
bool isDeclaration = Var->isDeclaration();
bool isPIC = getRelocationModel() == Reloc::PIC_;
bool isPIE = Options.PositionIndependentExecutable;
// FIXME: what should we do for protected and internal visibility?
// For variables, is internal different from hidden?
bool isHidden = Var->hasHiddenVisibility();
TLSModel::Model Model;
if (isPIC && !isPIE) {
if (isLocal || isHidden)
Model = TLSModel::LocalDynamic;
else
Model = TLSModel::GeneralDynamic;
} else {
if (!isDeclaration || isHidden)
Model = TLSModel::LocalExec;
else
Model = TLSModel::InitialExec;
}
// If the user specified a more specific model, use that.
TLSModel::Model SelectedModel = getSelectedTLSModel(Var);
if (SelectedModel > Model)
return SelectedModel;
return Model;
}
/// getOptLevel - Returns the optimization level: None, Less,
/// Default, or Aggressive.
CodeGenOpt::Level TargetMachine::getOptLevel() const {
if (!CodeGenInfo)
return CodeGenOpt::Default;
return CodeGenInfo->getOptLevel();
}
bool TargetMachine::getAsmVerbosityDefault() {
return AsmVerbosityDefault;
}
void TargetMachine::setAsmVerbosityDefault(bool V) {
AsmVerbosityDefault = V;
}
bool TargetMachine::getFunctionSections() {
return FunctionSections;
}
bool TargetMachine::getDataSections() {
return DataSections;
}
void TargetMachine::setFunctionSections(bool V) {
FunctionSections = V;
}
void TargetMachine::setDataSections(bool V) {
DataSections = V;
}