I am working on this:

http://lev.vlakno.cz/~rdivacky/llvm-ppc64-tls.patch

Implementes working local exec TLS

As of r158307.

Compiling a file with Clang containing a

static __thread int

variable, I get this crash now:

only local-exec TLS mode supported
UNREACHABLE executed at PPCISelLowering.cpp:1244!
0 clang 0x0000000001ad1d8f
1 clang 0x0000000001ad3ff2
2 libpthread.so.0 0x0000003d6220eb70
3 libc.so.6 0x0000003d61630265 gsignal + 53
4 libc.so.6 0x0000003d61631d10 abort + 272
5 clang 0x0000000001aba702 llvm::llvm_unreachable_internal(char const*, char const*, unsigned int) + 354
6 clang 0x000000000134861c
7 clang 0x000000000136ef8e llvm::PPCTargetLowering::LowerOperation(llvm::SDValue, llvm::SelectionDAG&) const + 894
8 clang 0x000000000148493c
9 clang 0x0000000001488ead llvm::SelectionDAG::Legalize() + 269
10 clang 0x0000000001434924 llvm::SelectionDAGISel::CodeGenAndEmitDAG() + 1076
11 clang 0x00000000014358a1 llvm::SelectionDAGISel::SelectBasicBlock(llvm::ilist_iterator<llvm::Instruction const>, llvm::ilist_iterator<llvm::Instruction const>, bool&) + 273
12 clang 0x000000000143793f llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) + 2079
13 clang 0x0000000001438d9f llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) + 1151
14 clang 0x0000000001341a16
15 clang 0x0000000001a2ff0d llvm::FPPassManager::runOnFunction(llvm::Function&) + 557
16 clang 0x0000000001a2fff3 llvm::FPPassManager::runOnModule(llvm::Module&) + 51
17 clang 0x0000000001a308e1 llvm::MPPassManager::runOnModule(llvm::Module&) + 497
18 clang 0x0000000001a30c7b llvm::PassManagerImpl::run(llvm::Module&) + 171
19 clang 0x000000000075ee28 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::Module*, clang::BackendAction, llvm::raw_ostream*) + 1560
20 clang 0x000000000075c389
21 clang 0x00000000008c3099 clang::ParseAST(clang::Sema&, bool, bool) + 857
22 clang 0x000000000075adb4 clang::CodeGenAction::ExecuteAction() + 68
23 clang 0x0000000000624e41 clang::FrontendAction::Execute() + 145
24 clang 0x0000000000602dd1 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) + 337
25 clang 0x00000000005ec194 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) + 1348
26 clang 0x00000000005e18d8 cc1_main(char const**, char const**, char const*, void*) + 648
27 clang 0x00000000005eb0ae main + 7214
28 libc.so.6 0x0000003d6161d994 __libc_start_main + 244
29 clang 0x00000000005dfef9

Any idea how I can specify that TLS mode, and why does it matter?

This is fixed. All TLS modes are supported now.

This is fixed. All TLS modes are supported now.

Just a hint, for 32-bit PPC this doesn't seem to work as of r178888. At the moment I cannot try HEAD, but I strongly suspect that this PR has been closed prematurely. (r178888 is well after 2013-02-18)

Just a heads-up :-)