FXC as DownstreamCompiler (#1844)

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

* WIP Fxc as downstream compiler.

* First pass FXC downstream compiler working.

* GCC compile fix.

* Fix FXC parsing issue.

* Special case filesystem access.

* Use StringUtil getSlice.

* Fix isses with not emitting source for FXC.

* Small fixes for DXBC handling.

1 files changed, 62 insertions, 0 deletions

diff --git a/source/compiler-core/slang-include-system.h b/source/compiler-core/slang-include-system.h
new file mode 100644
index 000000000..70f6dd81e
--- /dev/null
+++ b/source/compiler-core/slang-include-system.h
@@ -0,0 +1,62 @@
+#ifndef SLANG_INCLUDE_SYSTEM_H
+#define SLANG_INCLUDE_SYSTEM_H
+// slang-include-system.h
+
+#include "../compiler-core/slang-source-loc.h"
+
+namespace Slang
+{
+
+// A directory to be searched when looking for files (e.g., `#include`)
+struct SearchDirectory
+{
+    SearchDirectory() = default;
+    SearchDirectory(SearchDirectory const& other) = default;
+    SearchDirectory(String const& path)
+        : path(path)
+    {}
+
+    String path;
+};
+
+/// A list of directories to search for files (e.g., `#include`)
+struct SearchDirectoryList
+{
+    // A parent list that should also be searched
+    SearchDirectoryList*    parent = nullptr;
+
+    // Directories to be searched
+    List<SearchDirectory>   searchDirectories;
+};
+
+/* A helper class that builds basic include handling on top of searchDirectories/fileSystemExt and optionally a sourceManager */
+struct IncludeSystem
+{
+    IncludeSystem(SearchDirectoryList* searchDirectories, ISlangFileSystemExt* fileSystemExt, SourceManager* sourceManager = nullptr) :
+        m_searchDirectories(searchDirectories),
+        m_fileSystemExt(fileSystemExt),
+        m_sourceManager(sourceManager)
+    {
+    }
+
+    SlangResult findFile(const String& pathToInclude, const String& pathIncludedFrom, PathInfo& outPathInfo);
+    SlangResult findFile(SlangPathType fromPathType, const String& fromPath, const String& path, PathInfo& outPathInfo);
+    String simplifyPath(const String& path);
+    SlangResult loadFile(const PathInfo& pathInfo, ComPtr<ISlangBlob>& outBlob);
+
+    SlangResult findAndLoadFile(const String& pathToInclude, const String& pathIncludedFrom, PathInfo& outPathInfo, ComPtr<ISlangBlob>& outBlob);
+
+    SearchDirectoryList* getSearchDirectoryList() const { return m_searchDirectories; }
+    ISlangFileSystemExt* getFileSystem() const { return m_fileSystemExt; }
+    SourceManager* getSourceManager() const { return m_sourceManager; }
+
+protected:
+    
+    SearchDirectoryList* m_searchDirectories;
+    ISlangFileSystemExt* m_fileSystemExt;
+    SourceManager* m_sourceManager;                 ///< If not set, will not look up the content in the source manager
+};
+
+}
+
+#endif  // SLANG_INCLUDE_HANDLER_H