CUDA layout corner cases/testing (#1881)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Add support for sizeOf/alignOf/offsetOf to stdlib.
Add $G intrinsic expansion that works of the generic parameters not the param type

* Test cuda layout.

* Fix CUDA layout issues.
Fix reflection to handle other built in types.
Fix __offsetOf

* Tests of reflection and layout as reported directly from CUDA.

* Comment about use of aligned size as size.

* Fix warning from VS.

* Check alignment is pow2.

* Small improvements to alignment calcs.

* Tab to spaces.

* Fix alignment pointer sizes on 32 bit OS for CUDA.

* Fix CUDA reflection on 32 bit.

2 files changed, 84 insertions, 0 deletions

diff --git a/prelude/slang-cpp-prelude.h b/prelude/slang-cpp-prelude.h
index 725be4b42..ffd18cf32 100644
--- a/prelude/slang-cpp-prelude.h
+++ b/prelude/slang-cpp-prelude.h
@@ -36,6 +36,81 @@
 #   define SLANG_INFINITY   INFINITY
 #endif
 
+// Detect the compiler type
+
+#ifndef SLANG_COMPILER
+#    define SLANG_COMPILER
+
+/*
+Compiler defines, see http://sourceforge.net/p/predef/wiki/Compilers/
+NOTE that SLANG_VC holds the compiler version - not just 1 or 0
+*/
+#    if defined(_MSC_VER)
+#        if _MSC_VER >= 1900
+#            define SLANG_VC 14
+#        elif _MSC_VER >= 1800
+#            define SLANG_VC 12
+#        elif _MSC_VER >= 1700
+#            define SLANG_VC 11
+#        elif _MSC_VER >= 1600
+#            define SLANG_VC 10
+#        elif _MSC_VER >= 1500
+#            define SLANG_VC 9
+#        else
+#            error "unknown version of Visual C++ compiler"
+#        endif
+#    elif defined(__clang__)
+#        define SLANG_CLANG 1
+#    elif defined(__SNC__)
+#        define SLANG_SNC 1
+#    elif defined(__ghs__)
+#        define SLANG_GHS 1
+#    elif defined(__GNUC__) /* note: __clang__, __SNC__, or __ghs__ imply __GNUC__ */
+#        define SLANG_GCC 1
+#    else
+#        error "unknown compiler"
+#    endif
+/*
+Any compilers not detected by the above logic are now now explicitly zeroed out.
+*/
+#    ifndef SLANG_VC
+#        define SLANG_VC 0
+#    endif
+#    ifndef SLANG_CLANG
+#        define SLANG_CLANG 0
+#    endif
+#    ifndef SLANG_SNC
+#        define SLANG_SNC 0
+#    endif
+#    ifndef SLANG_GHS
+#        define SLANG_GHS 0
+#    endif
+#    ifndef SLANG_GCC
+#        define SLANG_GCC 0
+#    endif
+#endif /* SLANG_COMPILER */
+
+#define SLANG_GCC_FAMILY (SLANG_CLANG || SLANG_SNC || SLANG_GHS || SLANG_GCC)
+
+// GCC Specific
+#if SLANG_GCC_FAMILY
+#	define SLANG_ALIGN_OF(T)	__alignof__(T)
+// Use this macro instead of offsetof, because gcc produces warning if offsetof is used on a 
+// non POD type, even though it produces the correct result
+#   define SLANG_OFFSET_OF(T, ELEMENT) (size_t(&((T*)1)->ELEMENT) - 1)
+#endif // SLANG_GCC_FAMILY
+
+// Microsoft VC specific
+#if SLANG_VC
+#   define SLANG_ALIGN_OF(T) __alignof(T)
+#endif // SLANG_VC
+
+// Default impls
+
+#ifndef SLANG_OFFSET_OF
+#   define SLANG_OFFSET_OF(X, Y) offsetof(X, Y)
+#endif
+
 #include "slang-cpp-types.h"
 #include "slang-cpp-scalar-intrinsics.h"
 
diff --git a/prelude/slang-cuda-prelude.h b/prelude/slang-cuda-prelude.h
index 91094a75e..01c658e0b 100644
--- a/prelude/slang-cuda-prelude.h
+++ b/prelude/slang-cuda-prelude.h
@@ -15,6 +15,15 @@
 #include <optix.h>
 #endif
 
+// Define slang offsetof implementation 
+#ifndef SLANG_OFFSET_OF
+#   define SLANG_OFFSET_OF(type, member) (size_t)((char*)&(((type *)0)->member) - (char*)0)
+#endif
+
+#ifndef SLANG_ALIGN_OF
+#   define SLANG_ALIGN_OF(type) __alignof__(type)
+#endif
+
 // Must be large enough to cause overflow and therefore infinity
 #ifndef SLANG_INFINITY
 #   define SLANG_INFINITY   ((float)(1e+300 * 1e+300))