Move the support for using .init_array from ARM to the generic

TargetLoweringObjectFileELF. Use this to support it on X86. Unlike ARM,
on X86 it is not easy to find out if .init_array should be used or not, so
the decision is made via TargetOptions and defaults to off.

Add a command line option to llc that enables it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158692 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llc/llc.cpp

@@ -244,6 +244,10 @@ SegmentedStacks("segmented-stacks",
   cl::desc("Use segmented stacks if possible."),
   cl::init(false));
 
+static cl::opt<bool>
+UseInitArray("use-init-array",
+  cl::desc("Use .init_array instead of .ctors."),
+  cl::init(false));
 
 // GetFileNameRoot - Helper function to get the basename of a filename.
 static inline std::string
@@ -418,6 +422,7 @@ int main(int argc, char **argv) {
   Options.TrapFuncName = TrapFuncName;
   Options.PositionIndependentExecutable = EnablePIE;
   Options.EnableSegmentedStacks = SegmentedStacks;
+  Options.UseInitArray = UseInitArray;
 
   std::auto_ptr<TargetMachine>
     target(TheTarget->createTargetMachine(TheTriple.getTriple(),