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
This commit is contained in:
Hans Wennborg
2012-06-23 11:37:03 +00:00
parent 47cbc4e0ee
commit ce718ff9f4
24 changed files with 707 additions and 48 deletions

View File

@ -102,6 +102,17 @@ static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
}
}
static GlobalVariable::ThreadLocalMode GetDecodedThreadLocalMode(unsigned Val) {
switch (Val) {
case 0: return GlobalVariable::NotThreadLocal;
default: // Map unknown non-zero value to general dynamic.
case 1: return GlobalVariable::GeneralDynamicTLSModel;
case 2: return GlobalVariable::LocalDynamicTLSModel;
case 3: return GlobalVariable::InitialExecTLSModel;
case 4: return GlobalVariable::LocalExecTLSModel;
}
}
static int GetDecodedCastOpcode(unsigned Val) {
switch (Val) {
default: return -1;
@ -1544,9 +1555,10 @@ bool BitcodeReader::ParseModule(bool Resume) {
GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
if (Record.size() > 6)
Visibility = GetDecodedVisibility(Record[6]);
bool isThreadLocal = false;
GlobalVariable::ThreadLocalMode TLM = GlobalVariable::NotThreadLocal;
if (Record.size() > 7)
isThreadLocal = Record[7];
TLM = GetDecodedThreadLocalMode(Record[7]);
bool UnnamedAddr = false;
if (Record.size() > 8)
@ -1554,12 +1566,11 @@ bool BitcodeReader::ParseModule(bool Resume) {
GlobalVariable *NewGV =
new GlobalVariable(*TheModule, Ty, isConstant, Linkage, 0, "", 0,
isThreadLocal, AddressSpace);
TLM, AddressSpace);
NewGV->setAlignment(Alignment);
if (!Section.empty())
NewGV->setSection(Section);
NewGV->setVisibility(Visibility);
NewGV->setThreadLocal(isThreadLocal);
NewGV->setUnnamedAddr(UnnamedAddr);
ValueList.push_back(NewGV);

View File

@ -379,6 +379,17 @@ static unsigned getEncodedVisibility(const GlobalValue *GV) {
llvm_unreachable("Invalid visibility");
}
static unsigned getEncodedThreadLocalMode(const GlobalVariable *GV) {
switch (GV->getThreadLocalMode()) {
case GlobalVariable::NotThreadLocal: return 0;
case GlobalVariable::GeneralDynamicTLSModel: return 1;
case GlobalVariable::LocalDynamicTLSModel: return 2;
case GlobalVariable::InitialExecTLSModel: return 3;
case GlobalVariable::LocalExecTLSModel: return 4;
}
llvm_unreachable("Invalid TLS model");
}
// Emit top-level description of module, including target triple, inline asm,
// descriptors for global variables, and function prototype info.
static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
@ -487,7 +498,7 @@ static void WriteModuleInfo(const Module *M, const ValueEnumerator &VE,
GV->getVisibility() != GlobalValue::DefaultVisibility ||
GV->hasUnnamedAddr()) {
Vals.push_back(getEncodedVisibility(GV));
Vals.push_back(GV->isThreadLocal());
Vals.push_back(getEncodedThreadLocalMode(GV));
Vals.push_back(GV->hasUnnamedAddr());
} else {
AbbrevToUse = SimpleGVarAbbrev;