Improvements around IR representation and memory usage (#635)

* * Remove dispose from IRInst
* Use MemoryArena instead of MemoryPool
* Make all IRInst not require Dtor - by having ref counted array store ptrs that need freeing

* Increase block size - typically compilation is 2Mb of IR space(!)

* Fix issues around StringRepresentation::equal because null has special meaning.

* Don't bother to construct as String to compare StringRepresentation, just used UnownedStringSlice.

* Added fromLiteral support to UnownedStringSlice and use instead of strlen version.

* Use more conventional way to test StringRepresentation against a String.

* Fix gcc/clang template problem with cast.

1 files changed, 8 insertions, 6 deletions

diff --git a/source/slang/lower-to-ir.cpp b/source/slang/lower-to-ir.cpp
index 280b89fb8..d57872fc9 100644
--- a/source/slang/lower-to-ir.cpp
+++ b/source/slang/lower-to-ir.cpp
@@ -4549,19 +4549,21 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         IRInst* irInst,
         Decl*   decl)
     {
+        auto builder = getBuilder();
+
         for (auto targetMod : decl->GetModifiersOfType<TargetIntrinsicModifier>())
         {
-            auto decoration = getBuilder()->addDecoration<IRTargetIntrinsicDecoration>(irInst);
-            decoration->targetName = targetMod->targetToken.Content;
-
+            auto decoration = builder->addDecoration<IRTargetIntrinsicDecoration>(irInst);
+            decoration->targetName = builder->addStringToFree(targetMod->targetToken.Content);
+            
             auto definitionToken = targetMod->definitionToken;
             if (definitionToken.type == TokenType::StringLiteral)
             {
-                decoration->definition = getStringLiteralTokenValue(definitionToken);
+                decoration->definition = builder->addStringToFree(getStringLiteralTokenValue(definitionToken));
             }
             else
             {
-                decoration->definition = definitionToken.Content;
+                decoration->definition = builder->addStringToFree(definitionToken.Content);
             }
         }
     }
@@ -4900,7 +4902,7 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
             // target, and we need to reflect that at the IR level.
 
             auto decoration = getBuilder()->addDecoration<IRTargetDecoration>(irFunc);
-            decoration->targetName = targetMod->targetToken.Content;
+            decoration->targetName = getBuilder()->addStringToFree(targetMod->targetToken.Content);
         }
 
         // If this declaration was marked as having a target-specific lowering