StructTag versioning (#1888)

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

* WIP Abi struct.

* Use AbiSystem on SessionDesc.

* Use mask/shift constants.

* Fix issue causing warning on linux.

* Abi -> Api.

* Fix typo.

* Refactor to use StructTag.

* Mechanism to be able to follow fields.

* Field adding is working.

* WIP with StructTagConverter.

* First pass of StructTag appears to work. Still needs diagnostics.

* Small tidy up around Field.

* Use bit field to record what fields are recorded to remove allocation around the m_stack.
Use ScopeStack for RAII.

* Return SlangResult instead of pointers.

* Use SlangResult with copy.

* Split StructTagConverter implementations.

* Fix some bugs around lazy converting.

* First pass at unit test for StructTag.

* Testing StructTag going backwards in time.

* First pass as StructTag diagnostics.

* Make Traits a namespace.

* Fix some issues with Traits not being a class.

* Fix 32 bit warning.

1 files changed, 49 insertions, 17 deletions

diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index eed172bbf..8d82ca1b7 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -23,6 +23,7 @@
 #include "../core/slang-writer.h"
 
 #include "../compiler-core/slang-source-loc.h"
+#include "../compiler-core/slang-struct-tag-converter.h"
 
 #include "slang-ast-dump.h"
 
@@ -114,6 +115,32 @@ const char* getBuildTagString()
     return SLANG_TAG_VERSION;
 }
 
+static RefPtr<StructTagSystem> _createStructTagSystem()
+{
+    RefPtr<StructTagSystem> system = new StructTagSystem;
+
+    {
+#define SLANG_STRUCT_TAG_ADD_CATEGORY(x) system->addCategoryInfo(slang::StructTagCategory::x, #x);
+        SLANG_STRUCT_TAG_CATEGORIES(SLANG_STRUCT_TAG_ADD_CATEGORY)
+    }
+
+    {
+#define SLANG_STRUCT_TAG_ADD_TYPE(X) system->addType(slang::X::kStructTag, "slang::" #X, sizeof(slang::X));
+SLANG_TAGGED_STRUCTS(SLANG_STRUCT_TAG_ADD_TYPE)
+
+        // Add field that references more tagged structs
+        {
+            slang::SessionDesc desc;
+            auto field = StructTagTypeTraits::getFieldWithCount(&desc, &desc.targets, &desc.targetCount);
+
+            auto type = system->getType(slang::SessionDesc::kStructTag);
+            type->m_fields.add(field);
+        }
+    }
+
+    return system;
+}
+
 void Session::init()
 {
     SLANG_ASSERT(BaseTypeInfo::check());
@@ -131,6 +158,8 @@ void Session::init()
     m_sharedASTBuilder = new SharedASTBuilder;
     m_sharedASTBuilder->init(this);
 
+    m_structTagSystem = _createStructTagSystem();
+
     //  Use to create a ASTBuilder
     RefPtr<ASTBuilder> builtinAstBuilder(new ASTBuilder(m_sharedASTBuilder, "m_builtInLinkage::m_astBuilder"));
 
@@ -438,42 +467,45 @@ ISlangUnknown* Session::getInterface(const Guid& guid)
 }
 
 SLANG_NO_THROW SlangResult SLANG_MCALL Session::createSession(
-    slang::SessionDesc const&  desc,
+    slang::SessionDesc const&  inDesc,
     slang::ISession**          outSession)
 {
+    MemoryArena arena(1024);
+    
+    LazyStructTagConverter converter(getStructTagSystem(), &arena, nullptr);
+
+    const slang::SessionDesc* desc = nullptr;
+    SLANG_RETURN_ON_FAIL(converter.convertToCurrent(&inDesc, &desc));
+
     RefPtr<ASTBuilder> astBuilder(new ASTBuilder(m_sharedASTBuilder, "Session::astBuilder"));
     RefPtr<Linkage> linkage = new Linkage(this, astBuilder, getBuiltinLinkage());
 
-    Int targetCount = desc.targetCount;
-    const uint8_t* targetDescPtr = reinterpret_cast<const uint8_t*>(desc.targets);
-    for(Int ii = 0; ii < targetCount; ++ii)
     {
-        slang::TargetDesc targetDesc;
-        // Copy the size field first.
-        memcpy(&targetDesc.structureSize, targetDescPtr, sizeof(size_t));
-        // Copy the entire desc structure.
-        memcpy(&targetDesc, targetDescPtr, targetDesc.structureSize);
-        linkage->addTarget(targetDesc);
-        targetDescPtr += targetDesc.structureSize;
+        const Index targetCount = Index(desc->targetCount);
+        for(Index ii = 0; ii < targetCount; ++ii)
+        {
+            const auto& targetDesc = desc->targets[ii];
+            linkage->addTarget(targetDesc);
+        }
     }
 
-    if(desc.flags & slang::kSessionFlag_FalcorCustomSharedKeywordSemantics)
+    if(desc->flags & slang::kSessionFlag_FalcorCustomSharedKeywordSemantics)
     {
         linkage->m_useFalcorCustomSharedKeywordSemantics = true;
     }
 
-    linkage->setMatrixLayoutMode(desc.defaultMatrixLayoutMode);
+    linkage->setMatrixLayoutMode(desc->defaultMatrixLayoutMode);
 
-    Int searchPathCount = desc.searchPathCount;
+    Int searchPathCount = desc->searchPathCount;
     for(Int ii = 0; ii < searchPathCount; ++ii)
     {
-        linkage->addSearchPath(desc.searchPaths[ii]);
+        linkage->addSearchPath(desc->searchPaths[ii]);
     }
 
-    Int macroCount = desc.preprocessorMacroCount;
+    Int macroCount = desc->preprocessorMacroCount;
     for(Int ii = 0; ii < macroCount; ++ii)
     {
-        auto& macro = desc.preprocessorMacros[ii];
+        auto& macro = desc->preprocessorMacros[ii];
         linkage->addPreprocessorDefine(macro.name, macro.value);
     }