COM interfaces with host callable (#2258)

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

* Use TerminatedUnownedStringSlice for literals in output C++.

* Remove Escape/Unescape functions used in slang-token-reader.cpp
Add target type of 'host-cpp' etc to map to the target types.

* Fix some corner cases around string encoding.

* Added unit test for string escaping.
Fixed some assorted escaping bugs.

* Updated test output.

* Added decode test.

* Stop using hex output, to get around 'greedy' aspect. Use octal instead.

* Added HostHostCallable
Small changes to use ArtifactDesc/Info instead of large switches.

* Fix C++ emit to handle arbitrary function export.

* Add options handling for callable without an output being specified.

* Can compile with COM interface. Added example using com interface.

* Use the IR Ptr type instead of hack in C++ emit for interfaces.

* Fix issue with outputting the COM call when ptr is used.

* Fix crash issue on compilation failure.

1 files changed, 46 insertions, 0 deletions

diff --git a/prelude/slang-cpp-prelude.h b/prelude/slang-cpp-prelude.h
index 612f9ec9f..db83222a6 100644
--- a/prelude/slang-cpp-prelude.h
+++ b/prelude/slang-cpp-prelude.h
@@ -120,6 +120,52 @@ Any compilers not detected by the above logic are now now explicitly zeroed out.
 #   define SLANG_OFFSET_OF(X, Y) offsetof(X, Y)
 #endif
 
+// If slang.h has been included we don't need any of these definitions
+#ifndef SLANG_H
+
+/* Macro for declaring if a method is no throw. Should be set before the return parameter. */
+#ifndef SLANG_NO_THROW
+#   if SLANG_WINDOWS_FAMILY && !defined(SLANG_DISABLE_EXCEPTIONS)
+#       define SLANG_NO_THROW __declspec(nothrow)
+#   endif
+#endif
+#ifndef SLANG_NO_THROW
+#   define SLANG_NO_THROW
+#endif
+
+/* The `SLANG_STDCALL` and `SLANG_MCALL` defines are used to set the calling
+convention for interface methods.
+*/
+#ifndef SLANG_STDCALL
+#   if SLANG_MICROSOFT_FAMILY
+#       define SLANG_STDCALL __stdcall
+#   else
+#       define SLANG_STDCALL
+#   endif
+#endif
+#ifndef SLANG_MCALL
+#   define SLANG_MCALL SLANG_STDCALL
+#endif
+
+struct SlangUUID
+{
+    uint32_t data1;
+    uint16_t data2;
+    uint16_t data3;
+    uint8_t  data4[8];
+};
+
+typedef int32_t SlangResult;
+
+struct ISlangUnknown
+{
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL queryInterface(SlangUUID const& uuid, void** outObject) = 0;
+    virtual SLANG_NO_THROW uint32_t SLANG_MCALL addRef() = 0;
+    virtual SLANG_NO_THROW uint32_t SLANG_MCALL release() = 0;
+};
+
+#endif // SLANG_H
+
 #include "slang-cpp-types.h"
 #include "slang-cpp-scalar-intrinsics.h"