[RISCV] Use init_array instead of ctors for RISCV target, by default

Summary:
LLVM defaults to the newer .init_array/.fini_array scheme for static
constructors rather than the less desirable .ctors/.dtors (the UseCtors
flag defaults to false). This wasn't being respected in the RISC-V
backend because it fails to call TargetLoweringObjectFileELF::InitializeELF with the the appropriate
flag for UseInitArray.
This patch fixes this by implementing RISCVELFTargetObjectFile and overriding its Initialize method to call
InitializeELF(TM.Options.UseInitArray).

Reviewers: asb, apazos

Reviewed By: asb

Subscribers: mgorny, rbar, johnrusso, simoncook, jordy.potman.lists, sabuasal, niosHD, kito-cheng, shiva0217, llvm-commits

Differential Revision: https://reviews.llvm.org/D44750

llvm-svn: 328433

1 files changed, 19 insertions, 0 deletions

diff --git a/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp b/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp
new file mode 100644
index 00000000000..46e81b628b6
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVTargetObjectFile.cpp
@@ -0,0 +1,19 @@
+//===-- RISCVTargetObjectFile.cpp - RISCV Object Info -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVTargetObjectFile.h"
+#include "RISCVTargetMachine.h"
+
+using namespace llvm;
+
+void RISCVELFTargetObjectFile::Initialize(MCContext &Ctx,
+                                          const TargetMachine &TM) {
+  TargetLoweringObjectFileELF::Initialize(Ctx, TM);
+  InitializeELF(TM.Options.UseInitArray);
+}