Link GC metadata printers by default to llc

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54892 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/LinkAllAsmWriterComponents.h

@@ -0,0 +1,37 @@
+//===- llvm/Codegen/LinkAllAsmWriterComponents.h ----------------*- C++ -*-===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header file pulls in all assembler writer related passes for tools like
+// llc that need this functionality.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_LINKALLASMWRITERCOMPONENTS_H
+#define LLVM_CODEGEN_LINKALLASMWRITERCOMPONENTS_H
+
+#include "llvm/CodeGen/GCs.h"
+
+namespace {
+  struct ForceAsmWriterLinking {
+    ForceAsmWriterLinking() {
+      // We must reference the passes in such a way that compilers will not
+      // delete it all as dead code, even with whole program optimization,
+      // yet is effectively a NO-OP. As the compiler isn't smart enough
+      // to know that getenv() never returns -1, this will do the job.
+      if (std::getenv("bar") != (char*) -1)
+        return;
+
+      (void) llvm::createOcamlMetadataPrinter();
+
+    }
+  } ForceAsmWriterLinking; // Force link by creating a global definition.
+}
+
+#endif // LLVM_CODEGEN_LINKALLASMWRITERCOMPONENTS_H
+

tools/llc/llc.cpp

@@ -16,6 +16,7 @@
 #include "llvm/Bitcode/ReaderWriter.h"
 #include "llvm/CodeGen/FileWriters.h"
 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
+#include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
 #include "llvm/Target/SubtargetFeature.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetMachine.h"