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

Author: joker-eph

clang-tools-extra/clangd/index/dex/dexp/Dexp.cpp

@@ -91,7 +91,7 @@ class Command {
   // By resetting the parser options, we lost the standard -help flag.
   llvm::cl::opt<bool, false, llvm::cl::parser<bool>> Help{
       "help", llvm::cl::desc("Display available options"),
-      llvm::cl::ValueDisallowed, llvm::cl::cat(llvm::cl::GeneralCategory)};
+      llvm::cl::ValueDisallowed, llvm::cl::cat(llvm::cl::getGeneralCategory())};
   // FIXME: Allow commands to signal failure.
   virtual void run() = 0;
 

clang-tools-extra/clangd/indexer/IndexerMain.cpp

@@ -124,7 +124,7 @@ int main(int argc, const char **argv) {
   )";
 
   auto Executor = clang::tooling::createExecutorFromCommandLineArgs(
-      argc, argv, llvm::cl::GeneralCategory, Overview);
+      argc, argv, llvm::cl::getGeneralCategory(), Overview);
 
   if (!Executor) {
     llvm::errs() << llvm::toString(Executor.takeError()) << "\n";

clang/tools/clang-refactor/ClangRefactor.cpp

@@ -38,11 +38,11 @@ namespace opts {
 static cl::OptionCategory CommonRefactorOptions("Refactoring options");
 
 static cl::opt<bool> Verbose("v", cl::desc("Use verbose output"),
-                             cl::cat(cl::GeneralCategory),
+                             cl::cat(cl::getGeneralCategory()),
                              cl::sub(*cl::AllSubCommands));
 
 static cl::opt<bool> Inplace("i", cl::desc("Inplace edit <file>s"),
-                             cl::cat(cl::GeneralCategory),
+                             cl::cat(cl::getGeneralCategory()),
                              cl::sub(*cl::AllSubCommands));
 
 } // end namespace opts
@@ -613,7 +613,7 @@ int main(int argc, const char **argv) {
   ClangRefactorTool RefactorTool;
 
   auto ExpectedParser = CommonOptionsParser::create(
-      argc, argv, cl::GeneralCategory, cl::ZeroOrMore,
+      argc, argv, cl::getGeneralCategory(), cl::ZeroOrMore,
       "Clang-based refactoring tool for C, C++ and Objective-C");
   if (!ExpectedParser) {
     llvm::errs() << ExpectedParser.takeError();

llvm/docs/CommandLine.rst

@@ -661,7 +661,7 @@ declared, the command line option ``-help-list`` becomes visible which will
 print the command line options as uncategorized list.
 
 Note that Options that are not explicitly categorized will be placed in the
-``cl::GeneralCategory`` category.
+``cl::getGeneralCategory()`` category.
 
 .. _Reference Guide:
 

llvm/include/llvm/Support/ARMAttributeParser.h

@@ -71,9 +71,9 @@ class ARMAttributeParser : public ELFAttributeParser {
 
 public:
   ARMAttributeParser(ScopedPrinter *sw)
-      : ELFAttributeParser(sw, ARMBuildAttrs::ARMAttributeTags, "aeabi") {}
+      : ELFAttributeParser(sw, ARMBuildAttrs::getARMAttributeTags(), "aeabi") {}
   ARMAttributeParser()
-      : ELFAttributeParser(ARMBuildAttrs::ARMAttributeTags, "aeabi") {}
+      : ELFAttributeParser(ARMBuildAttrs::getARMAttributeTags(), "aeabi") {}
 };
 }
 

llvm/include/llvm/Support/ARMBuildAttributes.h

@@ -23,7 +23,7 @@
 namespace llvm {
 namespace ARMBuildAttrs {
 
-extern const TagNameMap ARMAttributeTags;
+const TagNameMap &getARMAttributeTags();
 
 enum SpecialAttr {
   // This is for the .cpu asm attr. It translates into one or more

llvm/include/llvm/Support/CommandLine.h

@@ -202,7 +202,7 @@ class OptionCategory {
 };
 
 // The general Option Category (used as default category).
-extern OptionCategory GeneralCategory;
+OptionCategory &getGeneralCategory();
 
 //===----------------------------------------------------------------------===//
 // SubCommand class
@@ -342,7 +342,7 @@ class Option {
       : NumOccurrences(0), Occurrences(OccurrencesFlag), Value(0),
         HiddenFlag(Hidden), Formatting(NormalFormatting), Misc(0),
         FullyInitialized(false), Position(0), AdditionalVals(0) {
-    Categories.push_back(&GeneralCategory);
+    Categories.push_back(&getGeneralCategory());
   }
 
   inline void setNumAdditionalVals(unsigned n) { AdditionalVals = n; }

llvm/include/llvm/Support/RISCVAttributeParser.h

@@ -27,9 +27,9 @@ class RISCVAttributeParser : public ELFAttributeParser {
 
 public:
   RISCVAttributeParser(ScopedPrinter *sw)
-      : ELFAttributeParser(sw, RISCVAttrs::RISCVAttributeTags, "riscv") {}
+      : ELFAttributeParser(sw, RISCVAttrs::getRISCVAttributeTags(), "riscv") {}
   RISCVAttributeParser()
-      : ELFAttributeParser(RISCVAttrs::RISCVAttributeTags, "riscv") {}
+      : ELFAttributeParser(RISCVAttrs::getRISCVAttributeTags(), "riscv") {}
 };
 
 } // namespace llvm

llvm/include/llvm/Support/RISCVAttributes.h

@@ -22,7 +22,7 @@
 namespace llvm {
 namespace RISCVAttrs {
 
-extern const TagNameMap RISCVAttributeTags;
+const TagNameMap &getRISCVAttributeTags();
 
 enum AttrType : unsigned {
   // Attribute types in ELF/.riscv.attributes.

llvm/include/llvm/Support/ScopedPrinter.h

@@ -32,8 +32,9 @@ template <typename T> struct EnumEntry {
   // "Advanced Micro Devices X86-64" on GNU style
   StringRef AltName;
   T Value;
-  EnumEntry(StringRef N, StringRef A, T V) : Name(N), AltName(A), Value(V) {}
-  EnumEntry(StringRef N, T V) : Name(N), AltName(N), Value(V) {}
+  constexpr EnumEntry(StringRef N, StringRef A, T V)
+      : Name(N), AltName(A), Value(V) {}
+  constexpr EnumEntry(StringRef N, T V) : Name(N), AltName(N), Value(V) {}
 };
 
 struct HexNumber {

llvm/include/llvm/Support/WithColor.h

@@ -20,7 +20,7 @@ namespace cl {
 class OptionCategory;
 }
 
-extern cl::OptionCategory ColorCategory;
+extern cl::OptionCategory &getColorCategory();
 
 // Symbolic names for various syntax elements.
 enum class HighlightColor {

llvm/lib/Support/ARMBuildAttrs.cpp

@@ -63,6 +63,7 @@ static const TagNameItem tagData[] = {
     {ARMBuildAttrs::ABI_align_preserved, "Tag_ABI_align8_preserved"},
 };
 
-const TagNameMap llvm::ARMBuildAttrs::ARMAttributeTags(tagData,
-                                                       sizeof(tagData) /
-                                                           sizeof(TagNameItem));
+constexpr TagNameMap ARMAttributeTags{tagData};
+const TagNameMap &llvm::ARMBuildAttrs::getARMAttributeTags() {
+  return ARMAttributeTags;
+}