ISPC: DynamicLibrary test now passes on windows.

The MSVC linker needs to know what MSVC runtime a shared library
needs. ISPC objects don't have a '/DIRECTIVE' entry for the
MSVC runtime as they have no dependency on it. Therefore
we need to add a C or C++ source to each shared library so
the MSVC linker knows what runtime to embed

Tests/ISPC/DynamicLibrary/CMakeLists.txt

@@ -9,12 +9,14 @@ endif()
 
 add_library(ispc_objects1 STATIC extra.ispc extra.cxx)
 add_library(ispc_objects2 SHARED simple.ispc)
+target_sources(ispc_objects2 PRIVATE simple.cxx)
 
 set_target_properties(ispc_objects1 PROPERTIES POSITION_INDEPENDENT_CODE ON)
+
 set_target_properties(ispc_objects1 PROPERTIES ISPC_INSTRUCTION_SETS "sse2-i32x4;avx1-i32x16;avx2-i32x4")
 set_target_properties(ispc_objects2 PROPERTIES ISPC_INSTRUCTION_SETS "sse2-i32x4")
 
-target_link_libraries(ispc_objects2 PRIVATE ispc_objects1)
+target_link_libraries(ispc_objects2 PUBLIC ispc_objects1)
 
 add_executable(ISPCDynamicLibrary main.cxx)
 target_link_libraries(ISPCDynamicLibrary PUBLIC ispc_objects2)

Tests/ISPC/DynamicLibrary/extra.cxx

@@ -2,7 +2,13 @@
 
 #include "extra.ispc.h"
 
-int extra()
+#ifdef _WIN32
+#  define EXPORT __declspec(dllexport)
+#else
+#  define EXPORT
+#endif
+
+EXPORT int extra()
 {
   float vin[16], vout[16];
   for (int i = 0; i < 16; ++i)

Tests/ISPC/DynamicLibrary/main.cxx

@@ -1,15 +1,17 @@
-#include <stdio.h>
 
-#include "simple.ispc.h"
 
-int main()
-{
-  float vin[16], vout[16];
-  for (int i = 0; i < 16; ++i)
-    vin[i] = i;
+#ifdef _WIN32
+#  define IMPORT __declspec(dllimport)
+#else
+#  define IMPORT
+#endif
 
-  ispc::simple(vin, vout, 16);
+IMPORT int simple();
+int extra();
 
-  for (int i = 0; i < 16; ++i)
-    printf("%d: simple(%f) = %f\n", i, vin[i], vout[i]);
+int main()
+{
+  extra();
+  simple();
+  return 0;
 }

Tests/ISPC/DynamicLibrary/simple.cxx

@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+#include "simple.ispc.h"
+
+#ifdef _WIN32
+#  define EXPORT __declspec(dllexport)
+#else
+#  define EXPORT
+#endif
+
+EXPORT int simple()
+{
+  float vin[16], vout[16];
+  for (int i = 0; i < 16; ++i)
+    vin[i] = i;
+
+  ispc::simple(vin, vout, 16);
+
+  for (int i = 0; i < 16; ++i)
+    printf("%d: extra(%f) = %f\n", i, vin[i], vout[i]);
+
+  return 0;
+}