[flang] Unimportant change to test the Windows build

[psteinfeld]

Don't pay attention to this!

[llvmbot]

@llvm/pr-subscribers-flang-driver

Author: Pete Steinfeld (psteinfeld)

Changes

Don't pay attention to this!

---

Full diff: https://github.com/llvm/llvm-project/pull/82811.diff

3 Files Affected:

• (modified) flang/CMakeLists.txt (+1-1)
• (modified) flang/include/flang/ISO_Fortran_binding.h (+4-4)
• (added) flang/test/Driver/iso-fortran-binding.cpp (+33)

diff --git a/flang/CMakeLists.txt b/flang/CMakeLists.txt
index 21617aeea0215e..861dbe22cbe63d 100644
--- a/flang/CMakeLists.txt
+++ b/flang/CMakeLists.txt
@@ -33,7 +33,7 @@ endif()
 
 option(FLANG_ENABLE_WERROR "Fail and stop building flang if a warning is triggered." OFF)
 
-# The out of tree builds of the compiler and the Fortran runtime
+# The out of tree builds of the compiler and the Fortran runtime 
 # must use the same setting of FLANG_RUNTIME_F128_MATH_LIB
 # to be composable. Failure to synchronize this setting may result
 # in linking errors or fatal failures in F128 runtime functions.
diff --git a/flang/include/flang/ISO_Fortran_binding.h b/flang/include/flang/ISO_Fortran_binding.h
index 4a28d3322a38f0..3f74a7e56f1755 100644
--- a/flang/include/flang/ISO_Fortran_binding.h
+++ b/flang/include/flang/ISO_Fortran_binding.h
@@ -125,7 +125,7 @@ namespace cfi_internal {
 // The below structure emulates a flexible array. This structure does not take
 // care of getting the memory storage. Note that it already contains one element
 // because a struct cannot be empty.
-template <typename T> struct FlexibleArray : T {
+extern "C++" template <typename T> struct FlexibleArray : T {
   RT_API_ATTRS T &operator[](int index) { return *(this + index); }
   const RT_API_ATTRS T &operator[](int index) const { return *(this + index); }
   RT_API_ATTRS operator T *() { return this; }
@@ -163,12 +163,12 @@ typedef struct CFI_cdesc_t {
 // needed, for C++'s CFI_cdesc_t's emulated flexible
 // dim[] array.
 namespace cfi_internal {
-template <int r> struct CdescStorage : public CFI_cdesc_t {
+extern "C++" template <int r> struct CdescStorage : public CFI_cdesc_t {
   static_assert((r > 1 && r <= CFI_MAX_RANK), "CFI_INVALID_RANK");
   CFI_dim_t dim[r - 1];
 };
-template <> struct CdescStorage<1> : public CFI_cdesc_t {};
-template <> struct CdescStorage<0> : public CFI_cdesc_t {};
+extern "C++" template <> struct CdescStorage<1> : public CFI_cdesc_t {};
+extern "C++" template <> struct CdescStorage<0> : public CFI_cdesc_t {};
 } // namespace cfi_internal
 #define CFI_CDESC_T(rank) \
   FORTRAN_ISO_NAMESPACE_::cfi_internal::CdescStorage<rank>
diff --git a/flang/test/Driver/iso-fortran-binding.cpp b/flang/test/Driver/iso-fortran-binding.cpp
new file mode 100644
index 00000000000000..aaafd7cccd07d0
--- /dev/null
+++ b/flang/test/Driver/iso-fortran-binding.cpp
@@ -0,0 +1,33 @@
+// UNSUPPORTED: system-windows
+// RUN: split-file %s %t
+// RUN: chmod +x %t/runtest.sh
+// RUN: %t/runtest.sh %t %t/cppfile.cpp %flang | FileCheck %s
+
+//--- cppfile.cpp
+extern "C" {
+#include "ISO_Fortran_binding.h"
+}
+#include <iostream>
+
+int main() {
+  std::cout << "PASS\n";
+  return 0;
+}
+
+// CHECK: PASS
+// clang-format off
+//--- runtest.sh
+#!/bin/bash
+TMPDIR=$1
+CPPFILE=$2
+FLANG=$3
+BINDIR=`dirname $FLANG`
+CPPCOMP=$BINDIR/clang++
+if [ -x $CPPCOMP ]
+then
+  $CPPCOMP $CPPFILE -o $TMPDIR/a.out
+  $TMPDIR/a.out # should print "PASS"
+else
+  # No clang compiler, just pass by default
+  echo "PASS"
+fi

[psteinfeld]

Tests are complete so I'm closing this.