[IR] Consolidate fixed metadata kind definitions (NFC)

[vsk]

Summary

Put the list of fixed metadata kinds in one place.

Testing: check-llvm with+without LLVM_ENABLE_MODULES=On

llvm/include/llvm/IR/FixedMetadataKinds.def

+/*===-- FixedMetadataKinds.def - Fixed metadata kind IDs -------*- C++ -*-=== *\
+|*
+|* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+|* See https://llvm.org/LICENSE.txt for license information.
+|* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+|*
+\*===----------------------------------------------------------------------===*/
+
+#ifndef LLVM_FIXED_MD_KIND
+#error "LLVM_FIXED_MD_KIND(EnumID, Name, Value) is not defined."
+#endif
+
+LLVM_FIXED_MD_KIND(MD_dbg, "dbg", 0)
+LLVM_FIXED_MD_KIND(MD_tbaa, "tbaa", 1)
+LLVM_FIXED_MD_KIND(MD_prof, "prof", 2)
+LLVM_FIXED_MD_KIND(MD_fpmath, "fpmath", 3)
+LLVM_FIXED_MD_KIND(MD_range, "range", 4)
+LLVM_FIXED_MD_KIND(MD_tbaa_struct, "tbaa.struct", 5)
+LLVM_FIXED_MD_KIND(MD_invariant_load, "invariant.load", 6)
+LLVM_FIXED_MD_KIND(MD_alias_scope, "alias.scope", 7)
+LLVM_FIXED_MD_KIND(MD_noalias, "noalias", 8)
+LLVM_FIXED_MD_KIND(MD_nontemporal, "nontemporal", 9)
+LLVM_FIXED_MD_KIND(MD_mem_parallel_loop_access,
+                    "llvm.mem.parallel_loop_access", 10)
+LLVM_FIXED_MD_KIND(MD_nonnull, "nonnull", 11)
+LLVM_FIXED_MD_KIND(MD_dereferenceable, "dereferenceable", 12)
+LLVM_FIXED_MD_KIND(MD_dereferenceable_or_null, "dereferenceable_or_null", 13)
+LLVM_FIXED_MD_KIND(MD_make_implicit, "make.implicit", 14)
+LLVM_FIXED_MD_KIND(MD_unpredictable, "unpredictable", 15)
+LLVM_FIXED_MD_KIND(MD_invariant_group, "invariant.group", 16)
+LLVM_FIXED_MD_KIND(MD_align, "align", 17)
+LLVM_FIXED_MD_KIND(MD_loop, "llvm.loop", 18)
+LLVM_FIXED_MD_KIND(MD_type, "type", 19)
+LLVM_FIXED_MD_KIND(MD_section_prefix, "section_prefix", 20)
+LLVM_FIXED_MD_KIND(MD_absolute_symbol, "absolute_symbol", 21)
+LLVM_FIXED_MD_KIND(MD_associated, "associated", 22)
+LLVM_FIXED_MD_KIND(MD_callees, "callees", 23)
+LLVM_FIXED_MD_KIND(MD_irr_loop, "irr_loop", 24)
+LLVM_FIXED_MD_KIND(MD_access_group, "llvm.access.group", 25)
+LLVM_FIXED_MD_KIND(MD_callback, "callback", 26)
+LLVM_FIXED_MD_KIND(MD_preserve_access_index, "llvm.preserve.access.index", 27)

llvm/include/llvm/IR/LLVMContext.h

public:
   LLVMContext();
   LLVMContext(LLVMContext &) = delete;
   LLVMContext &operator=(const LLVMContext &) = delete;
   ~LLVMContext();
 
   // Pinned metadata names, which always have the same value.  This is a
   // compile-time performance optimization, not a correctness optimization.
   enum : unsigned {
-    MD_dbg = 0,                       // "dbg"
-    MD_tbaa = 1,                      // "tbaa"
-    MD_prof = 2,                      // "prof"
-    MD_fpmath = 3,                    // "fpmath"
-    MD_range = 4,                     // "range"
-    MD_tbaa_struct = 5,               // "tbaa.struct"
-    MD_invariant_load = 6,            // "invariant.load"
-    MD_alias_scope = 7,               // "alias.scope"
-    MD_noalias = 8,                   // "noalias",
-    MD_nontemporal = 9,               // "nontemporal"
-    MD_mem_parallel_loop_access = 10, // "llvm.mem.parallel_loop_access"
-    MD_nonnull = 11,                  // "nonnull"
-    MD_dereferenceable = 12,          // "dereferenceable"
-    MD_dereferenceable_or_null = 13,  // "dereferenceable_or_null"
-    MD_make_implicit = 14,            // "make.implicit"
-    MD_unpredictable = 15,            // "unpredictable"
-    MD_invariant_group = 16,          // "invariant.group"
-    MD_align = 17,                    // "align"
-    MD_loop = 18,                     // "llvm.loop"
-    MD_type = 19,                     // "type"
-    MD_section_prefix = 20,           // "section_prefix"
-    MD_absolute_symbol = 21,          // "absolute_symbol"
-    MD_associated = 22,               // "associated"
-    MD_callees = 23,                  // "callees"
-    MD_irr_loop = 24,                 // "irr_loop"
-    MD_access_group = 25,             // "llvm.access.group"
-    MD_callback = 26,                 // "callback"
-    MD_preserve_access_index = 27,    // "llvm.preserve.*.access.index"
+#define LLVM_FIXED_MD_KIND(EnumID, Name, Value) EnumID = Value,
+#include "llvm/IR/FixedMetadataKinds.def"
+#undef LLVM_FIXED_MD_KIND
   };
 
   /// Known operand bundle tag IDs, which always have the same value.  All
   /// operand bundle tags that LLVM has special knowledge of are listed here.
   /// Additionally, this scheme allows LLVM to efficiently check for specific
   /// operand bundle tags without comparing strings.
   enum : unsigned {
     OB_deopt = 0,         // "deopt"

llvm/include/llvm/module.modulemap

module LLVM_IR {
 
   umbrella "IR"
   module * { export * }
 
   // These are intended for (repeated) textual inclusion.
   textual header "IR/DebugInfoFlags.def"
   textual header "IR/Instruction.def"
   textual header "IR/Metadata.def"
+  textual header "IR/FixedMetadataKinds.def"
   textual header "IR/Value.def"
   textual header "IR/RuntimeLibcalls.def"
 }
 
 module LLVM_IRReader {
   requires cplusplus
   umbrella "IRReader"
   module * { export * }

llvm/lib/IR/LLVMContext.cpp

 #include <utility>
 
 using namespace llvm;
 
 LLVMContext::LLVMContext() : pImpl(new LLVMContextImpl(*this)) {
   // Create the fixed metadata kinds. This is done in the same order as the
   // MD_* enum values so that they correspond.
   std::pair<unsigned, StringRef> MDKinds[] = {
-    {MD_dbg, "dbg"},
-    {MD_tbaa, "tbaa"},
-    {MD_prof, "prof"},
-    {MD_fpmath, "fpmath"},
-    {MD_range, "range"},
-    {MD_tbaa_struct, "tbaa.struct"},
-    {MD_invariant_load, "invariant.load"},
-    {MD_alias_scope, "alias.scope"},
-    {MD_noalias, "noalias"},
-    {MD_nontemporal, "nontemporal"},
-    {MD_mem_parallel_loop_access, "llvm.mem.parallel_loop_access"},
-    {MD_nonnull, "nonnull"},
-    {MD_dereferenceable, "dereferenceable"},
-    {MD_dereferenceable_or_null, "dereferenceable_or_null"},
-    {MD_make_implicit, "make.implicit"},
-    {MD_unpredictable, "unpredictable"},
-    {MD_invariant_group, "invariant.group"},
-    {MD_align, "align"},
-    {MD_loop, "llvm.loop"},
-    {MD_type, "type"},
-    {MD_section_prefix, "section_prefix"},
-    {MD_absolute_symbol, "absolute_symbol"},
-    {MD_associated, "associated"},
-    {MD_callees, "callees"},
-    {MD_irr_loop, "irr_loop"},
-    {MD_access_group, "llvm.access.group"},
-    {MD_callback, "callback"},
-    {MD_preserve_access_index, "llvm.preserve.access.index"},
+#define LLVM_FIXED_MD_KIND(EnumID, Name, Value) {EnumID, Name},
+#include "llvm/IR/FixedMetadataKinds.def"
+#undef LLVM_FIXED_MD_KIND
   };
 
   for (auto &MDKind : MDKinds) {
     unsigned ID = getMDKindID(MDKind.second);
     assert(ID == MDKind.first && "metadata kind id drifted");
     (void)ID;
   }