From 43631f70f44b036ddfa5b40a15d3c9c19721b315 Mon Sep 17 00:00:00 2001
From: Eduard Valeyev <eduard@valeyev.net>
Date: Thu, 2 Apr 2020 09:07:09 -0400
Subject: [PATCH] attempt to reduce the compilation noise in the generated code
 by wrapping into pragmas

---
 CHANGES                     |  3 ++-
 include/libint2/config.h.in | 42 +++++++++++++++++++++++++++++++++++++
 src/bin/libint/context.cc   |  4 ++--
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/CHANGES b/CHANGES
index 57074721c..cd7cbdaa4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,9 +3,10 @@
 
 Following is a brief summary of changes made in each release of Libint.
 
-- 2019-04-01: 2.7.0-beta.5
+- 2019-04-02: 2.7.0-beta.5
   - made usable as a CMake subproject
   - the deprecated autotools build harness has been removed from the exported library; CMake is the only way to build exported libs
+  - reduced compilation noise in generated code
 
 - 2019-03-01: 2.7.0-beta.4
   - PR #159: fixed description of cmake option REQUIRE_CXX_API
diff --git a/include/libint2/config.h.in b/include/libint2/config.h.in
index d96590995..f67334ef1 100644
--- a/include/libint2/config.h.in
+++ b/include/libint2/config.h.in
@@ -305,4 +305,46 @@
 /* have posix_memalign ? */
 #undef HAVE_POSIX_MEMALIGN
 
+/* compiler type detection */
+#define LIBINT_COMPILER_ID_GNU 0
+#define LIBINT_COMPILER_ID_Clang 1
+#define LIBINT_COMPILER_ID_AppleClang 2
+#define LIBINT_COMPILER_ID_XLClang 3
+#define LIBINT_COMPILER_ID_Intel 4
+#if defined(__INTEL_COMPILER_BUILD_DATE)  /* macros like __ICC and even __INTEL_COMPILER can be affected by command options like -no-icc */
+# define LIBINT_COMPILER_ID LIBINT_COMPILER_ID_Intel
+# define LIBINT_COMPILER_IS_ICC 1
+#endif
+#if defined(__clang__) && !defined(LIBINT_COMPILER_IS_ICC)
+# define LIBINT_COMPILER_IS_CLANG 1
+# if defined(__apple_build_version__)
+#  define LIBINT_COMPILER_ID LIBINT_COMPILER_ID_AppleClang
+# elif defined(__ibmxl__)
+#  define LIBINT_COMPILER_ID LIBINT_COMPILER_ID_XLClang
+# else
+#  define LIBINT_COMPILER_ID LIBINT_COMPILER_ID_Clang
+# endif
+#endif
+#if defined(__GNUG__) && !defined(LIBINT_COMPILER_IS_ICC) && !defined(LIBINT_COMPILER_IS_CLANG)
+# define LIBINT_COMPILER_ID LIBINT_COMPILER_ID_GNU
+# define LIBINT_COMPILER_IS_GCC 1
+#endif
+
+/* ----------- pragma helpers ---------------*/
+#define LIBINT_PRAGMA(x) _Pragma(#x)
+/* same as LIBINT_PRAGMA(x), but expands x */
+#define LIBINT_XPRAGMA(x) LIBINT_PRAGMA(x)
+/* "concats" a and b with a space in between */
+#define LIBINT_CONCAT(a,b) a b
+#if defined(LIBINT_COMPILER_IS_CLANG)
+#define LIBINT_PRAGMA_CLANG(x) LIBINT_XPRAGMA( LIBINT_CONCAT(clang,x) )
+#else
+#define LIBINT_PRAGMA_CLANG(x)
+#endif
+#if defined(LIBINT_COMPILER_IS_GCC)
+#define LIBINT_PRAGMA_GCC(x) LIBINT_XPRAGMA( LIBINT_CONCAT(GCC,x) )
+#else
+#define LIBINT_PRAGMA_GCC(x)
+#endif
+
 #endif /* header guard */
diff --git a/src/bin/libint/context.cc b/src/bin/libint/context.cc
index 84bd249fd..c03d4c3b3 100644
--- a/src/bin/libint/context.cc
+++ b/src/bin/libint/context.cc
@@ -197,7 +197,7 @@ std::string
 CppCodeContext::code_prefix() const
 {
   if (cparams()->use_C_linking()) {
-    return "#ifdef __cplusplus\nextern \"C\" {\n#endif\n";
+    return "#ifdef __cplusplus\nLIBINT_PRAGMA_CLANG(diagnostic push)\nLIBINT_PRAGMA_CLANG(diagnostic ignored \"-Wunused-variable\")\nLIBINT_PRAGMA_GCC(diagnostic push)\nLIBINT_PRAGMA_GCC(diagnostic ignored \"-Wunused-variable\")\nextern \"C\" {\n#endif\n";
   }
   return "";
 }
@@ -206,7 +206,7 @@ std::string
 CppCodeContext::code_postfix() const
 {
   if (cparams()->use_C_linking()) {
-    return "#ifdef __cplusplus\n};\n#endif\n";
+    return "#ifdef __cplusplus\n};\nLIBINT_PRAGMA_CLANG(diagnostic pop)\nLIBINT_PRAGMA_GCC(diagnostic pop)\n#endif\n";
   }
   return "";
 }