Add struct version to DownstreamCompiler::CompileOptions interface (#2692)

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

* Add versioning to CompileOptions for DownstreamCompiler so we can add new options without breaking binary interface.

* Use builtin offset of directly.

1 files changed, 54 insertions, 6 deletions

diff --git a/source/compiler-core/slang-llvm-compiler.cpp b/source/compiler-core/slang-llvm-compiler.cpp
index 382dd0842..b34c05d42 100644
--- a/source/compiler-core/slang-llvm-compiler.cpp
+++ b/source/compiler-core/slang-llvm-compiler.cpp
@@ -6,6 +6,42 @@
 namespace Slang
 {
 
+class AliasDepreciatedDownstreamCompiler : public DownstreamCompilerBase
+{
+public:
+
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL compile(const CompileOptions& options, IArtifact** outArtifact) SLANG_OVERRIDE;
+    virtual SLANG_NO_THROW bool SLANG_MCALL canConvert(const ArtifactDesc& from, const ArtifactDesc& to) SLANG_OVERRIDE { return m_inner->canConvert(from, to); }
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL convert(IArtifact* from, const ArtifactDesc& to, IArtifact** outArtifact) SLANG_OVERRIDE { return m_inner->convert(from, to, outArtifact); }
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL getVersionString(slang::IBlob** outVersionString) { return m_inner->getVersionString(outVersionString); }
+    virtual SLANG_NO_THROW bool SLANG_MCALL isFileBased() { return m_inner->isFileBased(); }
+
+    template <typename T>
+    void initCompileOptionsDepreciated()
+    {
+        m_compileOptionsOffset = T::kStart;
+    }
+
+    AliasDepreciatedDownstreamCompiler(IDownstreamCompiler* inner) :
+        m_inner(inner)
+    {
+        m_desc = inner->getDesc();
+    }
+
+    ComPtr<IDownstreamCompiler> m_inner;
+    ptrdiff_t m_compileOptionsOffset = 0;
+};
+
+SlangResult AliasDepreciatedDownstreamCompiler::compile(const CompileOptions& options, IArtifact** outArtifact)
+{
+    if (m_compileOptionsOffset == 0)
+    {
+        return m_inner->compile(options, outArtifact);
+    }
+    const uint8_t* ptr = ((const uint8_t*)&options) + m_compileOptionsOffset;
+    return m_inner->compile(*(const CompileOptions*)ptr, outArtifact);
+}
+
 /* static */SlangResult LLVMDownstreamCompilerUtil::locateCompilers(const String& path, ISlangSharedLibraryLoader* loader, DownstreamCompilerSet* set)
 {
     ComPtr<ISlangSharedLibrary> library;
@@ -20,15 +56,27 @@ namespace Slang
 
     typedef SlangResult(*CreateDownstreamCompilerFunc)(const Guid& intf, IDownstreamCompiler** outCompiler);
 
-    auto fn = (CreateDownstreamCompilerFunc)library->findFuncByName("createLLVMDownstreamCompiler_V2");
-    if (!fn)
+    ComPtr<IDownstreamCompiler> downstreamCompiler;
+
+    if (auto fnV2 = (CreateDownstreamCompilerFunc)library->findFuncByName("createLLVMDownstreamCompiler_V2"))
     {
-        return SLANG_FAIL;
-    }
+        ComPtr<IDownstreamCompiler> innerDownstreamCompiler;
 
-    ComPtr<IDownstreamCompiler> downstreamCompiler;
+        SLANG_RETURN_ON_FAIL(fnV2(IDownstreamCompiler::getTypeGuid(), innerDownstreamCompiler.writeRef()));
 
-    SLANG_RETURN_ON_FAIL(fn(IDownstreamCompiler::getTypeGuid(), downstreamCompiler.writeRef()));
+        // We then need to wrap
+        AliasDepreciatedDownstreamCompiler* fix = new AliasDepreciatedDownstreamCompiler(innerDownstreamCompiler);
+        downstreamCompiler = fix;
+        fix->initCompileOptionsDepreciated<DownstreamCompileOptions_AliasDepreciated1>();
+    }
+    else if (auto fnV3 = (CreateDownstreamCompilerFunc)library->findFuncByName("createLLVMDownstreamCompiler_V3"))
+    {
+        SLANG_RETURN_ON_FAIL(fnV3(IDownstreamCompiler::getTypeGuid(), downstreamCompiler.writeRef()));
+    }
+    else
+    {
+        return SLANG_FAIL;
+    }
 
     set->addSharedLibrary(library);
     set->addCompiler(downstreamCompiler);