[branch] and [flatten] support (#2928)

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

* Small fixes and improvements around reflection tool.

* Make PrettyWriter printing a class.

* Add HLSL output support for [flatten] and [branch]

* Handle [branch] on switch.

6 files changed, 52 insertions, 3 deletions

diff --git a/source/slang/slang-emit-c-like.cpp b/source/slang/slang-emit-c-like.cpp
index c7ea3a09a..872a7a8b2 100644
--- a/source/slang/slang-emit-c-like.cpp
+++ b/source/slang/slang-emit-c-like.cpp
@@ -2792,6 +2792,8 @@ void CLikeSourceEmitter::emitRegion(Region* inRegion)
             {
                 auto ifRegion = (IfRegion*) region;
 
+                emitIfDecorationsImpl(ifRegion->ifElseInst);
+
                 // TODO: consider simplifying the code in
                 // the case where `ifRegion == null`
                 // so that we output `if(!condition) { elseRegion }`
@@ -2858,6 +2860,8 @@ void CLikeSourceEmitter::emitRegion(Region* inRegion)
             {
                 auto switchRegion = (SwitchRegion*) region;
 
+                emitSwitchDecorationsImpl(switchRegion->switchInst);
+                
                 // Emit the start of our statement.
                 m_writer->emit("switch(");
                 emitOperand(switchRegion->getCondition(), getInfo(EmitOp::General));
diff --git a/source/slang/slang-emit-c-like.h b/source/slang/slang-emit-c-like.h
index 636faad46..47eff1ac4 100644
--- a/source/slang/slang-emit-c-like.h
+++ b/source/slang/slang-emit-c-like.h
@@ -521,6 +521,9 @@ public:
     virtual void emitIntrinsicCallExprImpl(IRCall* inst, IRTargetIntrinsicDecoration* targetIntrinsic, EmitOpInfo const& inOuterPrec);
     virtual void emitFunctionPreambleImpl(IRInst* inst) { SLANG_UNUSED(inst); }
     virtual void emitLoopControlDecorationImpl(IRLoopControlDecoration* decl) { SLANG_UNUSED(decl); }
+    virtual void emitIfDecorationsImpl(IRIfElse* ifInst) { SLANG_UNUSED(ifInst); }
+    virtual void emitSwitchDecorationsImpl(IRSwitch* switchInst) { SLANG_UNUSED(switchInst); }
+    
     virtual void emitFuncDecorationImpl(IRDecoration* decoration) { SLANG_UNUSED(decoration); }
     virtual void emitLivenessImpl(IRInst* inst);
 
diff --git a/source/slang/slang-emit-hlsl.cpp b/source/slang/slang-emit-hlsl.cpp
index 3f6e79f4a..76300c18b 100644
--- a/source/slang/slang-emit-hlsl.cpp
+++ b/source/slang/slang-emit-hlsl.cpp
@@ -766,6 +766,26 @@ static bool _canEmitExport(const Profile& profile)
     Super::emitFuncDecorationsImpl(func);
 }
 
+void HLSLSourceEmitter::emitIfDecorationsImpl(IRIfElse* ifInst)
+{
+    if (ifInst->findDecorationImpl(kIROp_BranchDecoration))
+    {
+        m_writer->emit("[branch]\n");
+    }
+    else if (ifInst->findDecorationImpl(kIROp_FlattenDecoration))
+    {
+        m_writer->emit("[flatten]\n");
+    }
+}
+
+void HLSLSourceEmitter::emitSwitchDecorationsImpl(IRSwitch* switchInst)
+{
+    if (switchInst->findDecorationImpl(kIROp_BranchDecoration))
+    {
+        m_writer->emit("[branch]\n");
+    }
+}
+
 void HLSLSourceEmitter::emitFuncDecorationImpl(IRDecoration* decoration)
 {
     switch( decoration->getOp() )
diff --git a/source/slang/slang-emit-hlsl.h b/source/slang/slang-emit-hlsl.h
index 2e4eb29b9..f2440fe38 100644
--- a/source/slang/slang-emit-hlsl.h
+++ b/source/slang/slang-emit-hlsl.h
@@ -53,6 +53,9 @@ protected:
     virtual void emitFuncDecorationImpl(IRDecoration* decoration) SLANG_OVERRIDE;
     virtual void emitFuncDecorationsImpl(IRFunc* func) SLANG_OVERRIDE;
 
+    virtual void emitSwitchDecorationsImpl(IRSwitch* switchInst) SLANG_OVERRIDE;
+    virtual void emitIfDecorationsImpl(IRIfElse* ifInst) SLANG_OVERRIDE;
+
     virtual void handleRequiredCapabilitiesImpl(IRInst* inst) SLANG_OVERRIDE;
     
     virtual void emitGlobalInstImpl(IRInst* inst) SLANG_OVERRIDE;
diff --git a/source/slang/slang-ir-inst-defs.h b/source/slang/slang-ir-inst-defs.h
index fc020403d..0c5afb4af 100644
--- a/source/slang/slang-ir-inst-defs.h
+++ b/source/slang/slang-ir-inst-defs.h
@@ -624,6 +624,8 @@ INST(AllocateOpaqueHandle, allocateOpaqueHandle, 0, 0)
 
 INST(HighLevelDeclDecoration,               highLevelDecl,          1, 0)
     INST(LayoutDecoration,                  layout,                 1, 0)
+    INST(BranchDecoration,                  branch,                 0, 0)
+    INST(FlattenDecoration,                 flatten,                0, 0)
     INST(LoopControlDecoration,             loopControl,            1, 0)
     INST(LoopMaxItersDecoration,            loopMaxIters,           1, 0)
     INST(LoopInferredMaxItersDecoration,    loopInferredMaxIters,   2, 0)
diff --git a/source/slang/slang-lower-to-ir.cpp b/source/slang/slang-lower-to-ir.cpp
index 937262758..5df1db03b 100644
--- a/source/slang/slang-lower-to-ir.cpp
+++ b/source/slang/slang-lower-to-ir.cpp
@@ -5075,13 +5075,15 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         auto irCond = getSimpleVal(context,
             lowerRValueExpr(context, condExpr));
 
+        IRInst* ifInst = nullptr;
+
         if (elseStmt)
         {
             auto thenBlock = createBlock();
             auto elseBlock = createBlock();
             auto afterBlock = createBlock();
 
-            builder->emitIfElse(irCond, thenBlock, elseBlock, afterBlock);
+            ifInst = builder->emitIfElse(irCond, thenBlock, elseBlock, afterBlock);
 
             insertBlock(thenBlock);
             lowerStmt(context, thenStmt);
@@ -5097,13 +5099,22 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
             auto thenBlock = createBlock();
             auto afterBlock = createBlock();
 
-            builder->emitIf(irCond, thenBlock, afterBlock);
+            ifInst = builder->emitIf(irCond, thenBlock, afterBlock);
 
             insertBlock(thenBlock);
             lowerStmt(context, thenStmt);
 
             insertBlock(afterBlock);
         }
+
+        if (stmt->findModifier<FlattenAttribute>())
+        {
+            builder->addDecoration(ifInst, kIROp_FlattenDecoration);
+        }
+        if (stmt->findModifier<BranchAttribute>())
+        {
+            builder->addDecoration(ifInst, kIROp_BranchDecoration);
+        }
     }
 
     void addLoopDecorations(
@@ -5828,7 +5839,7 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         // prepared to emit the `switch` instruction
         // itself.
         builder->setInsertInto(initialBlock);
-        builder->emitSwitch(
+        auto switchInst = builder->emitSwitch(
             conditionVal,
             breakLabel,
             defaultLabel,
@@ -5840,6 +5851,12 @@ struct StmtLoweringVisitor : StmtVisitor<StmtLoweringVisitor>
         // This is the block that subsequent code will go into.
         insertBlock(breakLabel);
         context->shared->breakLabels.remove(stmt);
+
+        // If there is the branch attribute output the IR decoration
+        if (stmt->hasModifier<BranchAttribute>())
+        {
+            builder->addDecoration(switchInst, kIROp_BranchDecoration);
+        }
     }
 };