User defined downstream compiler prelude (#1028)

* Added setDownstreamCompilerPrelude
Renamed setPassThroughPath to setDownstreamCompilerPath.
Fixed tests.
Added prelude directory & code to TestToolUtil to setup default preludes for testing/command line apis.

* Fix merge problem

* Remove hacks to make prelude work by adding a search path as no longer needed with 'user prelude'.

* Split up prelude into scalar intrinsics, and types.
Use slang.h for main header.
slang-cpp-prelude.h can now just include what it needs (relative to prelude directory) and define the few remaining things/work arounds.

* Fix typo.

1 files changed, 13 insertions, 3 deletions

diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index eef0dff6f..601312def 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -146,14 +146,14 @@ SLANG_NO_THROW SlangProfileID SLANG_MCALL Session::findProfile(
     return Slang::Profile::LookUp(name).raw;
 }
 
-SLANG_NO_THROW void SLANG_MCALL Session::setPassThroughPath(
+SLANG_NO_THROW void SLANG_MCALL Session::setDownstreamCompilerPath(
     SlangPassThrough inPassThrough,
     char const* path)
 {
     PassThroughMode passThrough = PassThroughMode(inPassThrough);
     SLANG_ASSERT(int(passThrough) > int(PassThroughMode::None) && int(passThrough) < int(PassThroughMode::CountOf));
     
-    if (m_passThroughPaths[int(passThrough)] != path)
+    if (m_downstreamCompilerPaths[int(passThrough)] != path)
     {
         // If it's changed we should unload any shared libraries that use it
         switch (passThrough)
@@ -187,10 +187,20 @@ SLANG_NO_THROW void SLANG_MCALL Session::setPassThroughPath(
         }
 
         // Set the path
-        m_passThroughPaths[int(passThrough)] = path;
+        m_downstreamCompilerPaths[int(passThrough)] = path;
     }
 }
 
+SLANG_NO_THROW void SLANG_MCALL Session::setDownstreamCompilerPrelude(
+    SlangPassThrough inPassThrough,
+    char const* prelude)
+{
+    PassThroughMode passThrough = PassThroughMode(inPassThrough);
+    SLANG_ASSERT(int(passThrough) > int(PassThroughMode::None) && int(passThrough) < int(PassThroughMode::CountOf));
+
+    m_downstreamCompilerPreludes[int(passThrough)] = prelude;
+}
+
 struct IncludeHandlerImpl : IncludeHandler
 {
     Linkage*    linkage;