From 017900d57edd5cc516aedb56d3bff834aeee2eca Mon Sep 17 00:00:00 2001 From: William S Fulton Date: Tue, 25 Jan 2022 00:28:08 +0000 Subject: [PATCH] Extern template tweaks Document extern template functions support. Extern templates result in new warning to differentiate from template explicit instantiation definition warning. --- CHANGES.current | 16 +++++++++ Doc/Manual/CPlusPlus11.html | 35 ++++++++++++++++--- Doc/Manual/Warnings.html | 1 + Examples/test-suite/cpp11_template_explicit.i | 3 +- .../cpp_template_explicit_instantiation.i | 24 +++++++++++++ ...cpp_template_explicit_instantiation.stderr | 4 +++ Source/CParse/parser.y | 21 +++++------ Source/Include/swigwarn.h | 1 + 8 files changed, 89 insertions(+), 16 deletions(-) create mode 100644 Examples/test-suite/errors/cpp_template_explicit_instantiation.i create mode 100644 Examples/test-suite/errors/cpp_template_explicit_instantiation.stderr diff --git a/CHANGES.current b/CHANGES.current index a9ba1ebaf..59257dc09 100644 --- a/CHANGES.current +++ b/CHANGES.current @@ -7,6 +7,22 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/ Version 4.1.0 (in progress) =========================== +2022-01-25: wsfulton + New warning 327 for extern templates, eg: + + extern template class std::vector; + extern template void Func(); + + results in warning + + example.i:3: Warning 327: Extern template ignored. + example.i:4: Warning 327: Extern template ignored. + + Extern template classes previously resulted in warning 320. + +2022-01-24: romintomasetti + #2131 #2157 C++11 extern function template parsing error fix. + 2022-01-21: wsfulton #2120 #2138 Replace legacy PCRE dependency with PCRE2. This requires changes for building SWIG from source. See updated diff --git a/Doc/Manual/CPlusPlus11.html b/Doc/Manual/CPlusPlus11.html index e5d7fbc2d..86a35bfaa 100644 --- a/Doc/Manual/CPlusPlus11.html +++ b/Doc/Manual/CPlusPlus11.html @@ -144,14 +144,39 @@ When either of these is used from a target language, a runtime call is made to o

7.2.3 Extern template

-

SWIG correctly parses the keywords extern template. +

SWIG correctly parses extern template explicit instantiation declarations. However, this template instantiation suppression in a translation unit has no relevance outside of the C++ compiler and so is not used by SWIG. -SWIG only uses %template for instantiating and wrapping templates.

+SWIG only uses %template for instantiating and wrapping templates. +Consider the class template below: +

-template class std::vector<int>;        // C++03 explicit instantiation in C++
-extern template class std::vector<int>; // C++11 explicit instantiation suppression in C++
-%template(VectorInt) std::vector<int>;  // SWIG instantiation
+// Class template
+template class std::vector<int>;        // C++03 template explicit instantiation definition in C++
+extern template class std::vector<int>; // C++11 template explicit instantiation declaration (extern template)
+%template(VectorInt) std::vector<int>;  // SWIG template instantiation
+
+ +

+The above result in warnings: +

+ +
+
+example.i:2: Warning 320: Explicit template instantiation ignored.
+example.i:3: Warning 327: Extern template ignored.
+
+
+ +

+Similarly for the function template below: +

+ +
+// Function template
+template void Func<int>();              // C++03 template explicit instantiation definition in C++
+extern template void Func<int>();       // C++11 template explicit instantiation declaration (extern template)
+%template(FuncInt) Func<int>;           // SWIG template instantiation

7.2.4 Initializer lists

diff --git a/Doc/Manual/Warnings.html b/Doc/Manual/Warnings.html index 02197f1cb..5d4d3773b 100644 --- a/Doc/Manual/Warnings.html +++ b/Doc/Manual/Warnings.html @@ -428,6 +428,7 @@ example.i(4) : Syntax error in input(1).
  • 324. Named nested template instantiations not supported. Processing as if no name was given to %template().
  • 325. Nested kind not currently supported (name ignored).
  • 326. Deprecated %extend name used - the kind name 'name' should be used instead of the typedef name 'name'. +
  • 327. Extern template ignored.
  • 350. operator new ignored.
  • 351. operator delete ignored.
  • 352. operator+ ignored. diff --git a/Examples/test-suite/cpp11_template_explicit.i b/Examples/test-suite/cpp11_template_explicit.i index 0a76b93d8..630342862 100644 --- a/Examples/test-suite/cpp11_template_explicit.i +++ b/Examples/test-suite/cpp11_template_explicit.i @@ -4,8 +4,9 @@ */ %module cpp11_template_explicit -/* Explicitely silence SWIG warning related to explicit templates */ +/* Suppress SWIG warnings related to explicit template instantiation and extern templates */ #pragma SWIG nowarn=SWIGWARN_PARSE_EXPLICIT_TEMPLATE +#pragma SWIG nowarn=SWIGWARN_PARSE_EXTERN_TEMPLATE %inline %{ diff --git a/Examples/test-suite/errors/cpp_template_explicit_instantiation.i b/Examples/test-suite/errors/cpp_template_explicit_instantiation.i new file mode 100644 index 000000000..97513724b --- /dev/null +++ b/Examples/test-suite/errors/cpp_template_explicit_instantiation.i @@ -0,0 +1,24 @@ +%module xxx + +%inline %{ +namespace std { + template class vector {}; +} +template void Func() {} +%} + +%inline %{ +// Class template +template class std::vector; // C++03 template explicit instantiation definition in C++ +extern template class std::vector; // C++11 template explicit instantiation declaration (extern template) +%} +%template(VectorInt) std::vector; // SWIG template instantiation + +%inline %{ +// Function template +template void Func(); // C++03 template explicit instantiation definition in C++ +extern template void Func(); // C++11 template explicit instantiation declaration (extern template) +%} +%template(FuncInt) Func; // SWIG template instantiation + + diff --git a/Examples/test-suite/errors/cpp_template_explicit_instantiation.stderr b/Examples/test-suite/errors/cpp_template_explicit_instantiation.stderr new file mode 100644 index 000000000..052d3de27 --- /dev/null +++ b/Examples/test-suite/errors/cpp_template_explicit_instantiation.stderr @@ -0,0 +1,4 @@ +cpp_template_explicit_instantiation.i:12: Warning 320: Explicit template instantiation ignored. +cpp_template_explicit_instantiation.i:13: Warning 327: Extern template ignored. +cpp_template_explicit_instantiation.i:19: Warning 320: Explicit template instantiation ignored. +cpp_template_explicit_instantiation.i:20: Warning 327: Extern template ignored. diff --git a/Source/CParse/parser.y b/Source/CParse/parser.y index a21d029e0..0796362bc 100644 --- a/Source/CParse/parser.y +++ b/Source/CParse/parser.y @@ -4355,29 +4355,30 @@ cpp_template_decl : TEMPLATE LESSTHAN template_parms GREATERTHAN { parsing_template_declaration = 0; } - /* Explicit template instantiation */ + /* Class template explicit instantiation definition */ | TEMPLATE cpptype idcolon { Swig_warning(WARN_PARSE_EXPLICIT_TEMPLATE, cparse_file, cparse_line, "Explicit template instantiation ignored.\n"); $$ = 0; } - /* Explicit function template instantiation */ + /* Function template explicit instantiation definition */ | TEMPLATE cpp_alternate_rettype idcolon LPAREN parms RPAREN { - Swig_warning(WARN_PARSE_EXPLICIT_TEMPLATE, cparse_file, cparse_line, "Explicit function template instantiation ignored.\n"); + Swig_warning(WARN_PARSE_EXPLICIT_TEMPLATE, cparse_file, cparse_line, "Explicit template instantiation ignored.\n"); $$ = 0; - } + } - /* Explicit class template instantiation without the translation unit */ + /* Class template explicit instantiation declaration (extern template) */ | EXTERN TEMPLATE cpptype idcolon { - Swig_warning(WARN_PARSE_EXPLICIT_TEMPLATE, cparse_file, cparse_line, "Explicit (extern) class template instantiation ignored.\n"); + Swig_warning(WARN_PARSE_EXTERN_TEMPLATE, cparse_file, cparse_line, "Extern template ignored.\n"); $$ = 0; } - /* Explicit function template instantiation without the translation unit */ + + /* Function template explicit instantiation declaration (extern template) */ | EXTERN TEMPLATE cpp_alternate_rettype idcolon LPAREN parms RPAREN { - Swig_warning(WARN_PARSE_EXPLICIT_TEMPLATE, cparse_file, cparse_line, "Explicit (extern) function template instantiation ignored.\n"); + Swig_warning(WARN_PARSE_EXTERN_TEMPLATE, cparse_file, cparse_line, "Extern template ignored.\n"); $$ = 0; - } - ; + } + ; cpp_template_possible: c_decl { $$ = $1; diff --git a/Source/Include/swigwarn.h b/Source/Include/swigwarn.h index 955a8773a..a57afbe36 100644 --- a/Source/Include/swigwarn.h +++ b/Source/Include/swigwarn.h @@ -93,6 +93,7 @@ #define WARN_PARSE_NESTED_TEMPLATE 324 #define WARN_PARSE_NAMED_NESTED_CLASS 325 #define WARN_PARSE_EXTEND_NAME 326 +#define WARN_PARSE_EXTERN_TEMPLATE 327 #define WARN_CPP11_LAMBDA 340 #define WARN_CPP11_ALIAS_DECLARATION 341 /* redundant now */