Enable resource directory for DXC.

[s-perron]

This change enables the resource directory for DXC. This will allow the HLSL standard headers to be accessed without using the -I option.

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff b26fd8099aa435c6a46b10b179549280ba3930b0 a6ebd017c51e5687fd040aaa7a8623c9ee57417f -- tools/clang/lib/Frontend/InitHeaderSearch.cpp tools/clang/tools/dxcompiler/dxcfilesystem.cpp tools/clang/tools/dxcompiler/dxcompilerobj.cpp

View the diff from clang-format here.

diff --git a/tools/clang/lib/Frontend/InitHeaderSearch.cpp b/tools/clang/lib/Frontend/InitHeaderSearch.cpp
index 38612398..fc5627f1 100644
--- a/tools/clang/lib/Frontend/InitHeaderSearch.cpp
+++ b/tools/clang/lib/Frontend/InitHeaderSearch.cpp
@@ -442,12 +442,12 @@ void InitHeaderSearch::AddDefaultIncludePaths(const LangOptions &Lang,
                                               const llvm::Triple &triple,
                                             const HeaderSearchOptions &HSOpts) {
 #if 1 // HLSL Change Starts
-    if (HSOpts.UseBuiltinIncludes) {
-        SmallString<128> P = StringRef(HSOpts.ResourceDir);
-        llvm::sys::path::append(P, "include");
-        AddUnmappedPath(P, Angled, false);
-    }
-    return;
+  if (HSOpts.UseBuiltinIncludes) {
+    SmallString<128> P = StringRef(HSOpts.ResourceDir);
+    llvm::sys::path::append(P, "include");
+    AddUnmappedPath(P, Angled, false);
+  }
+  return;
 #else
   // NB: This code path is going away. All of the logic is moving into the
   // driver which has the information necessary to do target-specific
diff --git a/tools/clang/tools/dxcompiler/dxcfilesystem.cpp b/tools/clang/tools/dxcompiler/dxcfilesystem.cpp
index 19209df0..82633f08 100644
--- a/tools/clang/tools/dxcompiler/dxcfilesystem.cpp
+++ b/tools/clang/tools/dxcompiler/dxcfilesystem.cpp
@@ -397,9 +397,10 @@ public:
       }
     }
     if (compiler.getHeaderSearchOpts().UseBuiltinIncludes) {
-        SmallString<128> P = StringRef(compiler.getHeaderSearchOpts().ResourceDir);
-        llvm::sys::path::append(P, "include");
-        m_searchEntries.emplace_back(Unicode::UTF8ToWideStringOrThrow(P.c_str()));
+      SmallString<128> P =
+          StringRef(compiler.getHeaderSearchOpts().ResourceDir);
+      llvm::sys::path::append(P, "include");
+      m_searchEntries.emplace_back(Unicode::UTF8ToWideStringOrThrow(P.c_str()));
     }
   }
 
diff --git a/tools/clang/tools/dxcompiler/dxcompilerobj.cpp b/tools/clang/tools/dxcompiler/dxcompilerobj.cpp
index 95d2827a..398c91b1 100644
--- a/tools/clang/tools/dxcompiler/dxcompilerobj.cpp
+++ b/tools/clang/tools/dxcompiler/dxcompilerobj.cpp
@@ -1405,8 +1405,8 @@ public:
     // Pick additional arguments.
     clang::HeaderSearchOptions &HSOpts = compiler.getHeaderSearchOpts();
     HSOpts.UseBuiltinIncludes = true;
-    HSOpts.ResourceDir =
-      clang::CompilerInvocation::GetResourcesPath("Hoping this is not needed on any of our platforms", nullptr);
+    HSOpts.ResourceDir = clang::CompilerInvocation::GetResourcesPath(
+        "Hoping this is not needed on any of our platforms", nullptr);
     // Consider: should we force-include '.' if the source file is relative?
     for (const llvm::opt::Arg *A : Opts.Args.filtered(options::OPT_I)) {
       const bool IsFrameworkFalse = false;

• Check this box to apply formatting changes to this branch.

[s-perron]

I have something that "works", but there is a problem. I don't know the right way to pass new information from dxc::main to this point. I don't have the path for the executable from argv[0] available. It is skipped when passing along the argument.

This works on my linux system where GetResourcePath uses /proc/self/exe to get the executable, but I don't know how to set up these parameters to work on other platforms.

Note that we could call GetResourcePath in another place if we determine how to pass the inforamtion along. This just seemed like the best place for now because this is where we are processing the -I options.

[s-perron]

Things that still need to be done:

• Modify the cmake install to copy the header to the resource directory.
• Change the default path to something that makes sense for dxc.
• Manually test on a few different platforms to make sure it works.

[s-perron]

@pow2clk @llvm-beanz

Do you have any suggestions on how to implement this? I'm not sure how to proceed. I don't know how to pass information from the driver into the library without changing the public interface.