[ORC-RT][ORC] Introduce ELF/*nix Platform and runtime support.

This change adds support to ORCv2 and the Orc runtime library for static
initializers, C++ static destructors, and exception handler registration for
ELF-based platforms, at present Linux and FreeBSD on x86_64. It is based on the
MachO platform and runtime support introduced in bb5f97e3ad1.

Patch by Peter Housel. Thanks very much Peter!

Reviewed By: lhames

Differential Revision: https://reviews.llvm.org/D108081

1 files changed, 10 insertions, 3 deletions

diff --git a/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp b/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
index fd26008..3c22c93 100644
--- a/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
@@ -64,9 +64,9 @@ private:
       LGI.SymbolFlags[ES.intern(Sym->getName())] = Flags;
     }
 
-    if (G.getTargetTriple().isOSBinFormatMachO())
-      if (hasMachOInitSection(G))
-        LGI.InitSymbol = makeInitSymbol(ES, G);
+    if ((G.getTargetTriple().isOSBinFormatMachO() && hasMachOInitSection(G)) ||
+        (G.getTargetTriple().isOSBinFormatELF() && hasELFInitSection(G)))
+      LGI.InitSymbol = makeInitSymbol(ES, G);
 
     return LGI;
   }
@@ -82,6 +82,13 @@ private:
     return false;
   }
 
+  static bool hasELFInitSection(LinkGraph &G) {
+    for (auto &Sec : G.sections())
+      if (Sec.getName() == ".init_array")
+        return true;
+    return false;
+  }
+
   static SymbolStringPtr makeInitSymbol(ExecutionSession &ES, LinkGraph &G) {
     std::string InitSymString;
     raw_string_ostream(InitSymString)