CoverageMapping: Move getParams<InnerParamTy>(MCDCParams) into mcdc::

Fixup for #81227

Author: chapuni

clang/lib/CodeGen/CoverageMappingGen.cpp

@@ -190,8 +190,7 @@ class SourceMappingRegion {
   }
 
   const auto &getMCDCDecisionParams() const {
-    return CounterMappingRegion::getParams<const mcdc::DecisionParameters>(
-        MCDCParams);
+    return mcdc::getParams<const mcdc::DecisionParameters>(MCDCParams);
   }
 
   const mcdc::Parameters &getMCDCParams() const { return MCDCParams; }

llvm/include/llvm/ProfileData/Coverage/CoverageMapping.h

@@ -258,22 +258,12 @@ struct CounterMappingRegion {
   /// Parameters used for Modified Condition/Decision Coverage
   mcdc::Parameters MCDCParams;
 
-  template <class MaybeConstInnerParameters, class MaybeConstMCDCParameters>
-  static auto &getParams(MaybeConstMCDCParameters &MCDCParams) {
-    using InnerParameters =
-        typename std::remove_const<MaybeConstInnerParameters>::type;
-    MaybeConstInnerParameters *Params =
-        std::get_if<InnerParameters>(&MCDCParams);
-    assert(Params && "InnerParameters unavailable");
-    return *Params;
-  }
-
   const auto &getDecisionParams() const {
-    return getParams<const mcdc::DecisionParameters>(MCDCParams);
+    return mcdc::getParams<const mcdc::DecisionParameters>(MCDCParams);
   }
 
   const auto &getBranchParams() const {
-    return getParams<const mcdc::BranchParameters>(MCDCParams);
+    return mcdc::getParams<const mcdc::BranchParameters>(MCDCParams);
   }
 
   unsigned FileID = 0;

llvm/include/llvm/ProfileData/Coverage/MCDCTypes.h

@@ -14,6 +14,8 @@
 #define LLVM_PROFILEDATA_COVERAGE_MCDCTYPES_H
 
 #include <array>
+#include <cassert>
+#include <type_traits>
 #include <variant>
 
 namespace llvm::coverage::mcdc {
@@ -49,6 +51,19 @@ struct BranchParameters {
 using Parameters =
     std::variant<std::monostate, DecisionParameters, BranchParameters>;
 
+/// Check and get underlying params in MCDCParams.
+/// \tparam MaybeConstInnerParameters Type to get. May be const.
+/// \tparam MaybeConstMCDCParameters Expected inferred. May be const.
+/// \param MCDCParams May be const.
+template <class MaybeConstInnerParameters, class MaybeConstMCDCParameters>
+static auto &getParams(MaybeConstMCDCParameters &MCDCParams) {
+  using InnerParameters =
+      typename std::remove_const<MaybeConstInnerParameters>::type;
+  MaybeConstInnerParameters *Params = std::get_if<InnerParameters>(&MCDCParams);
+  assert(Params && "InnerParameters unavailable");
+  return *Params;
+}
+
 } // namespace llvm::coverage::mcdc
 
 #endif // LLVM_PROFILEDATA_COVERAGE_MCDCTYPES_H