`export` support in HLSL (#2188)

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

* Compile to a dxil library.

* Added CompileProduct.

* Support handling of ModuleLibrary.

* CacheBehavior -> Cache

* Use CompileProduct for -r references.

* CompileProduct -> Artifact.

* Determining an artifact type on binding.

* Determine binary linkability.

* Added Artifact::exists.

* Added ArtifactKeep.

* Small fixes.

* Small improvements to Artifact.

* Add zip extension.

* Fix some comments.

* Fix multiple adding of PublicDecoration.
Make public output export for DXIL/lib.
Add checking for simpleDecorations such that only added once.

* Use 'whole program' to identify library build.

* Add -target dxil so test infrastructure knows it needs DXC.

7 files changed, 105 insertions, 10 deletions

diff --git a/source/slang/slang-artifact.cpp b/source/slang/slang-artifact.cpp
index 612c2365d..770f2202a 100644
--- a/source/slang/slang-artifact.cpp
+++ b/source/slang/slang-artifact.cpp
@@ -148,6 +148,13 @@ static const KindExtension g_cpuKindExts[] =
 {
     switch (payload)
     {
+        case Payload::DXBC:
+        {
+            // It seems as if DXBC is potentially linkable from
+            // https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-appendix-keywords#export
+            return true;
+        }
+
         case Payload::DXIL:
         case Payload::PTX:
         case Payload::SPIRV:
@@ -397,16 +404,18 @@ SlangResult Artifact::requireFilePath(Keep keep, String& outFilePath)
             auto parentDir = Path::getParentDirectory(path);
             if (parentDir.getLength())
             {
-                // Prefix the lib
+                // Combine the name with path if their is a parent 
                 path = Path::combine(parentDir, buf);
             }
             else
             {
+                // Just use the name as is
                 path = buf;
             }
         }
     }
 
+    // If there is an extension append it
     if (ext.getLength())
     {
         path.appendChar('.');
diff --git a/source/slang/slang-compiler.cpp b/source/slang/slang-compiler.cpp
index 80899e69e..881194bcb 100644
--- a/source/slang/slang-compiler.cpp
+++ b/source/slang/slang-compiler.cpp
@@ -1203,11 +1203,26 @@ void printDiagnosticArg(StringBuilder& sb, CodeGenTarget val)
             auto targetReq = getTargetReq();
 
             const auto entryPointIndicesCount = entryPointIndices.getCount();
-             
-            if (entryPointIndicesCount == 0 && compilerType == PassThroughMode::Dxc)
+
+            // Whole program means
+            // * can have 0-N entry points
+            // * 'doesn't build into an executable/kernel'
+            // 
+            // So in some sense it is a library
+            if (targetReq->isWholeProgramRequest())
             {
-                // Can support no entry points on DXC because we can build libraries
-                profile = targetReq->getTargetProfile();
+                if (compilerType == PassThroughMode::Dxc)
+                {
+                    // Can support no entry points on DXC because we can build libraries
+                    profile = targetReq->getTargetProfile();
+                }
+                else
+                {
+                    auto downstreamCompilerName = TypeTextUtil::getPassThroughName((SlangPassThrough)compilerType);
+
+                    sink->diagnose(SourceLoc(), Diagnostics::downstreamCompilerDoesntSupportWholeProgramCompilation, downstreamCompilerName);
+                    return SLANG_FAIL;
+                }
             }
             else if (entryPointIndicesCount == 1)
             {
@@ -1909,11 +1924,12 @@ void printDiagnosticArg(StringBuilder& sb, CodeGenTarget val)
         // The current logic of `emitEntryPoints` takes a list of entry-point indices to
         // emit code for, so we construct such a list first.
         List<Int> entryPointIndices;
+
         m_entryPointResults.setCount(m_program->getEntryPointCount());
         entryPointIndices.setCount(m_program->getEntryPointCount());
         for (Index i = 0; i < entryPointIndices.getCount(); i++)
             entryPointIndices[i] = i;
-
+    
         auto& result = m_wholeProgramResult;
 
         CodeGenContext::Shared sharedCodeGenContext(this, entryPointIndices, sink, endToEndReq);
@@ -1929,7 +1945,7 @@ void printDiagnosticArg(StringBuilder& sb, CodeGenTarget val)
         DiagnosticSink*         sink,
         EndToEndCompileRequest* endToEndReq)
     {
-        // It is possible that entry points goot added to the `Program`
+        // It is possible that entry points got added to the `Program`
         // *after* we created this `TargetProgram`, so there might be
         // a request for an entry point that we didn't allocate space for.
         //
diff --git a/source/slang/slang-diagnostic-defs.h b/source/slang/slang-diagnostic-defs.h
index 6500bd1a0..e23d88fa4 100644
--- a/source/slang/slang-diagnostic-defs.h
+++ b/source/slang/slang-diagnostic-defs.h
@@ -135,6 +135,9 @@ DIAGNOSTIC(    97, Error, libraryDoesNotExist, "library '$0' does not exist")
 //
 
 DIAGNOSTIC(  100, Error, failedToLoadDownstreamCompiler, "failed to load downstream compiler '$0'")
+DIAGNOSTIC(  101, Error, downstreamCompilerDoesntSupportWholeProgramCompilation, "downstream compiler '$0' doesn't support whole program compilation")
+
+
 DIAGNOSTIC(99999, Note, noteFailedToLoadDynamicLibrary, "failed to load dynamic library '$0'")
 
 //
diff --git a/source/slang/slang-emit-hlsl.cpp b/source/slang/slang-emit-hlsl.cpp
index 09749546a..059a3f641 100644
--- a/source/slang/slang-emit-hlsl.cpp
+++ b/source/slang/slang-emit-hlsl.cpp
@@ -731,6 +731,28 @@ void HLSLSourceEmitter::emitFuncDecorationImpl(IRDecoration* decoration)
 {
     switch( decoration->getOp() )
     {
+    case kIROp_PublicDecoration:
+    {
+        auto profile = m_effectiveProfile;
+        
+        const auto family = profile.getFamily();
+        const auto stage = profile.getStage();
+        const auto version = profile.getVersion();
+
+        // I would perhaps ideally know that this was being compiled for 'library' stage.
+        // Stage::Unknown is currently also used for lib profiles.
+
+        // TODO(JS): Potentially can do export for fxc too, but for now we don't add.
+        
+        if (family == ProfileFamily::DX &&
+            version >= ProfileVersion::DX_6_1 &&
+            stage == Stage::Unknown)
+        {
+            m_writer->emit("export\n");
+        }
+        break;
+    }
+        
     case kIROp_NoInlineDecoration:
         m_writer->emit("[noinline]\n");
         break;
diff --git a/source/slang/slang-ir-insts.h b/source/slang/slang-ir-insts.h
index e4318177f..717e1be59 100644
--- a/source/slang/slang-ir-insts.h
+++ b/source/slang/slang-ir-insts.h
@@ -196,6 +196,8 @@ struct IRTypeConstraintDecoration : IRDecoration
     };                                  \
     /**/
 
+bool isSimpleDecoration(IROp op);
+
 /// A decoration that indicates that a variable represents
 /// a vulkan ray payload, and should have a location assigned
 /// to it.
@@ -2833,7 +2835,7 @@ public:
 
     void addPublicDecoration(IRInst* value)
     {
-        addDecoration(value, kIROp_PublicDecoration);
+        addDecoration(value, kIROp_PublicDecoration);   
     }
 
     void addNVAPIMagicDecoration(IRInst* value, UnownedStringSlice const& name)
diff --git a/source/slang/slang-ir.cpp b/source/slang/slang-ir.cpp
index 09a28e394..b53c247c3 100644
--- a/source/slang/slang-ir.cpp
+++ b/source/slang/slang-ir.cpp
@@ -23,8 +23,36 @@ namespace Slang
             sb << nameHint->getName();
     }
 
-    // !!!!!!!!!!!!!!!!!!!!!!!!!!!! DiagnosticSink Impls !!!!!!!!!!!!!!!!!!!!!
+    // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+
+    bool isSimpleDecoration(IROp op)
+    {
+        switch (op)
+        {
+            case kIROp_EarlyDepthStencilDecoration: return true;
+            case kIROp_GloballyCoherentDecoration: return true;
+            case kIROp_KeepAliveDecoration: return true;
+            case kIROp_LineAdjInputPrimitiveTypeDecoration: return true;
+            case kIROp_LineInputPrimitiveTypeDecoration: return true;
+            case kIROp_NoInlineDecoration: return true;
+            case kIROp_PointInputPrimitiveTypeDecoration: return true;
+            case kIROp_PreciseDecoration: return true;
+            case kIROp_PublicDecoration: return true;
+            case kIROp_ReadNoneDecoration: return true;
+            case kIROp_RequiresNVAPIDecoration: return true;
+            case kIROp_TriangleAdjInputPrimitiveTypeDecoration: return true;
+            case kIROp_TriangleInputPrimitiveTypeDecoration: return true;
+            case kIROp_UnsafeForceInlineEarlyDecoration: return true;
+            case kIROp_VulkanCallablePayloadDecoration: return true;
+            case kIROp_VulkanHitAttributesDecoration: return true;
+            case kIROp_VulkanRayPayloadDecoration: return true;
+            default: break;
+        }
+        return false;
+    }
 
+    
     IRInst* cloneGlobalValueWithLinkage(
         IRSpecContext*          context,
         IRInst*                 originalVal,
@@ -4172,6 +4200,16 @@ namespace Slang
 
     IRDecoration* IRBuilder::addDecoration(IRInst* value, IROp op, IRInst* const* operands, Int operandCount)
     {
+        // If it's a simple (ie stateless) decoration, don't add it again.
+        if (operandCount == 0 && isSimpleDecoration(op))
+        {
+            auto decoration = value->findDecorationImpl(op);
+            if (decoration)
+            {
+                return decoration;
+            }
+        }
+
         auto decoration = createInstWithTrailingArgs<IRDecoration>(
             this,
             op,
diff --git a/source/slang/slang-lower-to-ir.cpp b/source/slang/slang-lower-to-ir.cpp
index 842a1ce5f..7a99faa58 100644
--- a/source/slang/slang-lower-to-ir.cpp
+++ b/source/slang/slang-lower-to-ir.cpp
@@ -7424,9 +7424,14 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
             getBuilder()->addSimpleDecoration<IRNoInlineDecoration>(irFunc);
         }
 
-        if (decl->findModifier<PublicModifier>()) {
+#if 0
+        // Not needed as added as part of adding linkage decoration.
+        // Ie in call to addLinkageDecoration
+        if (decl->findModifier<PublicModifier>())
+        {
             getBuilder()->addSimpleDecoration<IRPublicDecoration>(irFunc);
         }
+#endif
 
         if (auto attr = decl->findModifier<InstanceAttribute>())
         {