[WebAssembly] Compute and export TLS block alignment
Summary:
Add immutable WASM global `__tls_align` which stores the alignment
requirements of the TLS segment.
Add `__builtin_wasm_tls_align()` intrinsic to get this alignment in Clang.
The expected usage has now changed to:
__wasm_init_tls(memalign(__builtin_wasm_tls_align(),
__builtin_wasm_tls_size()));
Reviewers: tlively, aheejin, sbc100, sunfish, alexcrichton
Reviewed By: tlively
Subscribers: dschuff, jgravelle-google, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65028
llvm-svn: 366624
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
index aaf3259..4de002c 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelDAGToDAG.cpp
@@ -224,6 +224,16 @@
ReplaceNode(Node, TLSSize);
return;
}
+ case Intrinsic::wasm_tls_align: {
+ MVT PtrVT = TLI->getPointerTy(CurDAG->getDataLayout());
+ assert(PtrVT == MVT::i32 && "only wasm32 is supported for now");
+
+ MachineSDNode *TLSAlign = CurDAG->getMachineNode(
+ WebAssembly::GLOBAL_GET_I32, DL, PtrVT,
+ CurDAG->getTargetExternalSymbol("__tls_align", MVT::i32));
+ ReplaceNode(Node, TLSAlign);
+ return;
+ }
}
break;
}