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, 15 insertions, 70 deletions

diff --git a/source/slang/slang-compiler.cpp b/source/slang/slang-compiler.cpp
index 75cd61bf9..07e2b66fe 100644
--- a/source/slang/slang-compiler.cpp
+++ b/source/slang/slang-compiler.cpp
@@ -474,7 +474,7 @@ namespace Slang
         return SLANG_E_NOT_IMPLEMENTED;
     }
 
-    static PassThroughMode _getExternalCompilerRequiredForTarget(CodeGenTarget target)
+    PassThroughMode getDownstreamCompilerRequiredForTarget(CodeGenTarget target)
     {
         switch (target)
         {
@@ -530,9 +530,22 @@ namespace Slang
         return PassThroughMode::None;
     }
 
+    PassThroughMode getPassThroughModeForCPPCompiler(CPPCompiler::CompilerType type)
+    {
+        typedef CPPCompiler::CompilerType CompilerType;
+
+        switch (type)
+        {
+            case CompilerType::VisualStudio:        return PassThroughMode::VisualStudio;
+            case CompilerType::GCC:                 return PassThroughMode::Gcc;
+            case CompilerType::Clang:               return PassThroughMode::Clang;
+            default:                                return PassThroughMode::None;
+        }
+    }
+
     SlangResult checkCompileTargetSupport(Session* session, CodeGenTarget target)
     {
-        const PassThroughMode mode = _getExternalCompilerRequiredForTarget(target);
+        const PassThroughMode mode = getDownstreamCompilerRequiredForTarget(target);
         return (mode != PassThroughMode::None) ?
             checkExternalCompilerSupport(session, mode) :
             SLANG_OK;
@@ -561,21 +574,6 @@ namespace Slang
         return translationUnit;
     }
 
-    static TranslationUnitRequest* _getTranslationUnit(
-        EndToEndCompileRequest* endToEndReq,
-        Int                     entryPointIndex)
-    {
-        // If there isn't an end-to-end compile going on,
-        // there can be no pass-through.
-        //
-        if (!endToEndReq) return nullptr;
-
-        auto frontEndReq = endToEndReq->getFrontEndReq();
-        auto entryPointReq = frontEndReq->getEntryPointReq(entryPointIndex);
-        auto translationUnit = entryPointReq->getTranslationUnit();
-        return translationUnit;
-    }
-
     static void _appendEscapedPath(const UnownedStringSlice& path, StringBuilder& outBuilder)
     {
         for (auto c : path)
@@ -1316,28 +1314,6 @@ SlangResult dissassembleDXILUsingDXC(
         }
         else
         {
-            // TODO(JS): This is a hack for two reasons
-            // * That we just inject the source path for C/C++ include paths if we find the file
-            // * We should access the files through the ISlangFileSystem
-
-            translationUnit = _getTranslationUnit(endToEndReq, entryPointIndex);
-
-            const auto& sourceFiles = translationUnit->getSourceFiles();
-            if (sourceFiles.getCount() == 1)
-            {
-                const SourceFile* sourceFile = sourceFiles[0];
-                const PathInfo& pathInfo = sourceFile->getPathInfo();
-                if (pathInfo.type == PathInfo::Type::FoundPath || pathInfo.type == PathInfo::Type::Normal || pathInfo.type == PathInfo::Type::FromString)
-                {
-                    String canonicalPath;
-                    if (File::exists(pathInfo.foundPath) && SLANG_SUCCEEDED(Path::getCanonical(pathInfo.foundPath, canonicalPath)))
-                    {
-                        String sourceDir = Path::getParentDirectory(canonicalPath);
-                        includePaths.add(sourceDir);                        
-                    }
-                }
-            }
-
             rawSource = emitCPPForEntryPoint(
                 slangRequest,
                 entryPoint,
@@ -1477,37 +1453,6 @@ SlangResult dissassembleDXILUsingDXC(
             }
         }
 
-        // TODO(JS): HACK! We need to include the prelude from somewhere, but where? The generated output
-        // is sitting in some temp directory.
-        // So here, we search all the 'sourceFiles', and try their paths for plausibility, and take the first
-        {
-            auto frontEndReq = endToEndReq->getFrontEndReq();
-            auto entryPointReq = frontEndReq->getEntryPointReq(entryPointIndex);
-            auto translationUnit = entryPointReq->getTranslationUnit();
-
-            for (SourceFile* sourceFile : translationUnit->m_sourceFiles)
-            {
-                const auto& pathInfo = sourceFile->getPathInfo();
-
-                if (pathInfo.type == PathInfo::Type::FoundPath ||
-                    pathInfo.type == PathInfo::Type::Normal)
-                {
-                    String originalSourceDirectory = Path::getParentDirectory(pathInfo.foundPath);
-
-                    if (originalSourceDirectory.getLength() && File::exists(originalSourceDirectory))
-                    {
-                        // We can't use this path directly, so make canonical so it is absolute
-                        StringBuilder canonicalPath;
-                        if (SLANG_SUCCEEDED(Path::getCanonical(originalSourceDirectory, canonicalPath)))
-                        {
-                            options.includePaths.add(canonicalPath.ProduceString());
-                            break;
-                        }
-                    }
-                }
-            }
-        }
-
         // Compile
         CPPCompiler::Output output;
         SLANG_RETURN_ON_FAIL(compiler->compile(options, output));