From 95348fdb623509eb22c04d4c7c19af8228c5a533 Mon Sep 17 00:00:00 2001
From: Tim Foley <tfoley@nvidia.com>
Date: Thu, 17 Aug 2017 14:17:29 -0700
Subject: [ir] Represent fields more direclty

Previously, a `StructType` was an ordinary instruction that took a variable number of types are operands, representing the types of fields.
This ends up being inconvenient for a few reasons:

- To add decorations to the fields, you'd end up having to decorate the struct type instead (SPIR-V has this problem)

- You need to compute field indices during lowering, when you might prefer to defer that until later

- The get/set field operations now need an index, which needs to be an explicit operand, which means a magic numeric literal floating around to represent the index

The new approach fixes for the first two of these, and at least makes the last one a bit nicer.
A `StructDecl` is now a parent instruction, and its sub-instructions represent the fields of the type - each field is an explicit instruction of type `StructField`.
The operation to extract a field takes a direct reference the struct field, so everything is quite explicit.
---
 source/slang/emit.cpp | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

(limited to 'source/slang/emit.cpp')

diff --git a/source/slang/emit.cpp b/source/slang/emit.cpp
index 35020249b..1f0436d8a 100644
--- a/source/slang/emit.cpp
+++ b/source/slang/emit.cpp
@@ -4016,8 +4016,8 @@ emitDeclImpl(decl, nullptr);
 
                 emitIRInstResultDecl(context, inst);
                 emitIROperand(context, fieldExtract->getBase());
-                emit(".field");
-                emit(fieldExtract->fieldIndex);
+                emit(".");
+                emit(getName(fieldExtract->getField()));
                 emit(";\n");
             }
             break;
@@ -4087,20 +4087,16 @@ emitDeclImpl(decl, nullptr);
 
     void emitIRStruct(
         EmitContext*    context,
-        IRStructType*   structType)
+        IRStructDecl*   structType)
     {
         emit("struct ");
         emit(getName(structType));
         emit("\n{\n");
-        auto fieldCount = structType->getFieldCount();
-        for( UInt ff = 0; ff < fieldCount; ++ff )
-        {
-            auto fieldType = structType->getFieldType(ff);
-
-            String fieldName = "field";
-            fieldName.append(ff);
 
-            emitIRType(context, fieldType, fieldName);
+        for(auto ff = structType->getFirstField(); ff; ff = ff->getNextField())
+        {
+            auto fieldType = ff->getFieldType();
+            emitIRType(context, fieldType, getName(ff));
             emit(";\n");
         }
         emit("};\n");
@@ -4119,7 +4115,7 @@ emitDeclImpl(decl, nullptr);
             break;
 
         case kIROp_StructType:
-            emitIRStruct(context, (IRStructType*) inst);
+            emitIRStruct(context, (IRStructDecl*) inst);
             break;
 
         default:
@@ -4254,7 +4250,7 @@ String emitEntryPoint(
     //
     // We'll try to detect the cases here:
     //
-#if 0
+#if 1
     if(!(translationUnit->compileFlags & SLANG_COMPILE_FLAG_NO_CHECKING ))
     {
         // This seems to be case (3), because the user is asking for full
-- 
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