Use ManagedStatic and lazy initialization of cl::opt in libSupport to make it free of global initializer

We can build it with -Werror=global-constructors now. This helps
in situation where libSupport is embedded as a shared library,
potential with dlopen/dlclose scenario, and when command-line
parsing or other facilities may not be involved. Avoiding the
implicit construction of these cl::opt can avoid double-registration
issues and other kind of behavior.

Reviewed By: lattner, jpienaar

Differential Revision: https://reviews.llvm.org/D105959

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/lib/Support/RISCVAttributes.cpp b/llvm/lib/Support/RISCVAttributes.cpp
index 201048e..9e62976 100644
--- a/llvm/lib/Support/RISCVAttributes.cpp
+++ b/llvm/lib/Support/RISCVAttributes.cpp
@@ -11,7 +11,7 @@
 using namespace llvm;
 using namespace llvm::RISCVAttrs;
 
-static const TagNameItem tagData[] = {
+static constexpr TagNameItem tagData[] = {
     {STACK_ALIGN, "Tag_stack_align"},
     {ARCH, "Tag_arch"},
     {UNALIGNED_ACCESS, "Tag_unaligned_access"},
@@ -20,6 +20,7 @@ static const TagNameItem tagData[] = {
     {PRIV_SPEC_REVISION, "Tag_priv_spec_revision"},
 };
 
-const TagNameMap llvm::RISCVAttrs::RISCVAttributeTags(tagData,
-                                                      sizeof(tagData) /
-                                                          sizeof(TagNameItem));
+constexpr TagNameMap RISCVAttributeTags{tagData};
+const TagNameMap &llvm::RISCVAttrs::getRISCVAttributeTags() {
+  return RISCVAttributeTags;
+}