[llvm] c189ec2 - Support: hoist `extern template` declarations

[Saleem Abdulrasool via llvm-commits]

Author: Saleem Abdulrasool
Date: 2021-09-08T10:09:43-07:00
New Revision: c189ec2e3f33b5805a1eaa48fe71a60d0a2f55ed

URL: https://github.com/llvm/llvm-project/commit/c189ec2e3f33b5805a1eaa48fe71a60d0a2f55ed
DIFF: https://github.com/llvm/llvm-project/commit/c189ec2e3f33b5805a1eaa48fe71a60d0a2f55ed.diff

LOG: Support: hoist `extern template` declarations

Precede the `extern template` declaration prior to use.  This is helpful
as it prevents the compiler from having to worry about instantiating the
template as it will be provided for.  This is particularly important for
Windows where `__declspec(dllexport)` will traverses inheritance clauses
resulting in an incorrect application of dll interface to declarations.

Added: 
    

Modified: 
    llvm/include/llvm/Support/CommandLine.h

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
index 14d7e21f78b2..ef95f9cca749 100644
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -926,6 +926,9 @@ template <class DataType> class basic_parser : public basic_parser_impl {
 //--------------------------------------------------
 // parser<bool>
 //
+
+extern template class basic_parser<bool>;
+
 template <> class parser<bool> : public basic_parser<bool> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -949,10 +952,11 @@ template <> class parser<bool> : public basic_parser<bool> {
   void anchor() override;
 };
 
-extern template class basic_parser<bool>;
-
 //--------------------------------------------------
 // parser<boolOrDefault>
+
+extern template class basic_parser<boolOrDefault>;
+
 template <> class parser<boolOrDefault> : public basic_parser<boolOrDefault> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -974,11 +978,12 @@ template <> class parser<boolOrDefault> : public basic_parser<boolOrDefault> {
   void anchor() override;
 };
 
-extern template class basic_parser<boolOrDefault>;
-
 //--------------------------------------------------
 // parser<int>
 //
+
+extern template class basic_parser<int>;
+
 template <> class parser<int> : public basic_parser<int> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -996,11 +1001,12 @@ template <> class parser<int> : public basic_parser<int> {
   void anchor() override;
 };
 
-extern template class basic_parser<int>;
-
 //--------------------------------------------------
 // parser<long>
 //
+
+extern template class basic_parser<long>;
+
 template <> class parser<long> final : public basic_parser<long> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -1018,11 +1024,12 @@ template <> class parser<long> final : public basic_parser<long> {
   void anchor() override;
 };
 
-extern template class basic_parser<long>;
-
 //--------------------------------------------------
 // parser<long long>
 //
+
+extern template class basic_parser<long long>;
+
 template <> class parser<long long> : public basic_parser<long long> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -1040,11 +1047,12 @@ template <> class parser<long long> : public basic_parser<long long> {
   void anchor() override;
 };
 
-extern template class basic_parser<long long>;
-
 //--------------------------------------------------
 // parser<unsigned>
 //
+
+extern template class basic_parser<unsigned>;
+
 template <> class parser<unsigned> : public basic_parser<unsigned> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -1062,11 +1070,12 @@ template <> class parser<unsigned> : public basic_parser<unsigned> {
   void anchor() override;
 };
 
-extern template class basic_parser<unsigned>;
-
 //--------------------------------------------------
 // parser<unsigned long>
 //
+
+extern template class basic_parser<unsigned long>;
+
 template <>
 class parser<unsigned long> final : public basic_parser<unsigned long> {
 public:
@@ -1085,11 +1094,12 @@ class parser<unsigned long> final : public basic_parser<unsigned long> {
   void anchor() override;
 };
 
-extern template class basic_parser<unsigned long>;
-
 //--------------------------------------------------
 // parser<unsigned long long>
 //
+
+extern template class basic_parser<unsigned long long>;
+
 template <>
 class parser<unsigned long long> : public basic_parser<unsigned long long> {
 public:
@@ -1109,11 +1119,12 @@ class parser<unsigned long long> : public basic_parser<unsigned long long> {
   void anchor() override;
 };
 
-extern template class basic_parser<unsigned long long>;
-
 //--------------------------------------------------
 // parser<double>
 //
+
+extern template class basic_parser<double>;
+
 template <> class parser<double> : public basic_parser<double> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -1131,11 +1142,12 @@ template <> class parser<double> : public basic_parser<double> {
   void anchor() override;
 };
 
-extern template class basic_parser<double>;
-
 //--------------------------------------------------
 // parser<float>
 //
+
+extern template class basic_parser<float>;
+
 template <> class parser<float> : public basic_parser<float> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -1153,11 +1165,12 @@ template <> class parser<float> : public basic_parser<float> {
   void anchor() override;
 };
 
-extern template class basic_parser<float>;
-
 //--------------------------------------------------
 // parser<std::string>
 //
+
+extern template class basic_parser<std::string>;
+
 template <> class parser<std::string> : public basic_parser<std::string> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -1178,11 +1191,12 @@ template <> class parser<std::string> : public basic_parser<std::string> {
   void anchor() override;
 };
 
-extern template class basic_parser<std::string>;
-
 //--------------------------------------------------
 // parser<char>
 //
+
+extern template class basic_parser<char>;
+
 template <> class parser<char> : public basic_parser<char> {
 public:
   parser(Option &O) : basic_parser(O) {}
@@ -1203,8 +1217,6 @@ template <> class parser<char> : public basic_parser<char> {
   void anchor() override;
 };
 
-extern template class basic_parser<char>;
-
 //--------------------------------------------------
 // PrintOptionDiff
 //