[NFC] Move FoldingSetNodeIDRef::ComputeHash and FoldingSetNodeID::Com…

…puteHash definitions to header

Lack of ComputeHash inlining slows down slightly FoldingSetBase::FindNodeOrInsertPos calls.
Inlining makes it faster which matters in particular for FoldingSet users in ASTContext.

Extracted from: https://reviews.llvm.org/D118385

Differential Revision: https://reviews.llvm.org/D118612

llvm/include/llvm/ADT/FoldingSet.h

@@ -16,6 +16,7 @@
 #ifndef LLVM_ADT_FOLDINGSET_H
 #define LLVM_ADT_FOLDINGSET_H
 
+#include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/Support/Allocator.h"
@@ -293,7 +294,9 @@ class FoldingSetNodeIDRef {
 
   /// ComputeHash - Compute a strong hash value for this FoldingSetNodeIDRef,
   /// used to lookup the node in the FoldingSetBase.
-  unsigned ComputeHash() const;
+  unsigned ComputeHash() const {
+    return static_cast<unsigned>(hash_combine_range(Data, Data + Size));
+  }
 
   bool operator==(FoldingSetNodeIDRef) const;
 
@@ -363,7 +366,9 @@ class FoldingSetNodeID {
 
   /// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used
   /// to lookup the node in the FoldingSetBase.
-  unsigned ComputeHash() const;
+  unsigned ComputeHash() const {
+    return FoldingSetNodeIDRef(Bits.data(), Bits.size()).ComputeHash();
+  }
 
   /// operator== - Used to compare two nodes to each other.
   bool operator==(const FoldingSetNodeID &RHS) const;

llvm/lib/Support/FoldingSet.cpp

@@ -12,7 +12,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/FoldingSet.h"
-#include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -25,12 +24,6 @@ using namespace llvm;
 //===----------------------------------------------------------------------===//
 // FoldingSetNodeIDRef Implementation
 
-/// ComputeHash - Compute a strong hash value for this FoldingSetNodeIDRef,
-/// used to lookup the node in the FoldingSetBase.
-unsigned FoldingSetNodeIDRef::ComputeHash() const {
-  return static_cast<unsigned>(hash_combine_range(Data, Data+Size));
-}
-
 bool FoldingSetNodeIDRef::operator==(FoldingSetNodeIDRef RHS) const {
   if (Size != RHS.Size) return false;
   return memcmp(Data, RHS.Data, Size*sizeof(*Data)) == 0;
@@ -110,12 +103,6 @@ void FoldingSetNodeID::AddNodeID(const FoldingSetNodeID &ID) {
   Bits.append(ID.Bits.begin(), ID.Bits.end());
 }
 
-/// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used to
-/// lookup the node in the FoldingSetBase.
-unsigned FoldingSetNodeID::ComputeHash() const {
-  return FoldingSetNodeIDRef(Bits.data(), Bits.size()).ComputeHash();
-}
-
 /// operator== - Used to compare two nodes to each other.
 ///
 bool FoldingSetNodeID::operator==(const FoldingSetNodeID &RHS) const {