Allow use of dxc compiler for DXIL generation (#241)

- Add shader model 6.0, 6.1, and 6.2 targets

- Add DXIL and DXIL assembly as output formats

- Add header for DXC API to `external/`

- Add `dxc-support.cpp` that wraps usage of the API

- Add `-pass-through dxc` option, equivalent to what we have for `fxc`

Notes:
* This does *not* include any logic to add `dxcompiler.dll` to our build process; that is way out of scope for the build complexity I'm ready to deal with
* For right now, the use of `dxcompiler.dll` is hard-coded, and it must be discoverable in the current executable's search path; options to customize can come later
* The `-pass-through` option is kind of silly because the code doesn't actually pay attention to the value (just whether it is set). If you set it to `fxc` but ask for DXIL, we pass through `dxc` anyway.

1 files changed, 3 insertions, 0 deletions

diff --git a/slang.h b/slang.h
index 11b34053c..5c84ce6f3 100644
--- a/slang.h
+++ b/slang.h
@@ -89,6 +89,8 @@ extern "C"
         SLANG_SPIRV_ASM,
         SLANG_DXBC,
         SLANG_DXBC_ASM,
+        SLANG_DXIL,
+        SLANG_DXIL_ASM,
     };
 
     /* A "container format" describes the way that the outputs
@@ -1079,6 +1081,7 @@ namespace slang
 #include "source/core/text-io.cpp"
 #include "source/slang/bytecode.cpp"
 #include "source/slang/diagnostics.cpp"
+#include "source/slang/dxc-support.cpp"
 #include "source/slang/emit.cpp"
 #include "source/slang/ir.cpp"
 #include "source/slang/lexer.cpp"