Preliminary Liveness tracking (#2218)

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

* WIP tracking liveness.

* Skeleton around adding liveness instructions.

* Calling into liveness tracking logic.
Adds live start to var insts.

* Liveness macros have initial output.

* Looking at different initialization scenarios.

* Some discussion around liveness.

* WIP for working out liveness end.

* WIP Updated liveness using use lists.

* Is now adding liveness information

* Some small fixes.

* WIP around liveness.

* Seems to output liveness correctly for current scenario.

* Tidy up liveness code.

* Update comment arounds liveness to current status.

* Small fixes to liveness test.

* Add support for call in liveness analysis.

* Improve liveness example with array access.

* Small updates to comments.

* Disable liveness test because inconsistencies with output on CI system.

* Fix some issues brought up in PR.

* Rename liveness instructions.

1 files changed, 41 insertions, 0 deletions

diff --git a/source/slang/slang-emit-c-like.cpp b/source/slang/slang-emit-c-like.cpp
index dccfde7b7..90ccb3e73 100644
--- a/source/slang/slang-emit-c-like.cpp
+++ b/source/slang/slang-emit-c-like.cpp
@@ -405,6 +405,43 @@ void CLikeSourceEmitter::emitType(IRType* type, NameLoc const& nameAndLoc)
     emitType(type, nameAndLoc.name, nameAndLoc.loc);
 }
 
+
+void CLikeSourceEmitter::emitLivenessImpl(IRInst* inst)
+{
+    
+    auto liveMarker = as<IRLiveRangeMarker>(inst);
+    if (!liveMarker)
+    {
+        return;
+    }
+
+    IRInst* referenced = liveMarker->getReferenced();
+    SLANG_ASSERT(referenced);
+
+    UnownedStringSlice text;
+    switch (inst->getOp())
+    {
+        case kIROp_LiveRangeStart:
+        {
+            text = UnownedStringSlice::fromLiteral("SLANG_LIVE_START");
+            break;
+        }
+        case kIROp_LiveRangeEnd:
+        {
+            text = UnownedStringSlice::fromLiteral("SLANG_LIVE_END");
+            break;
+        }
+        default: break;
+    }
+
+    m_writer->emit(text);
+    m_writer->emit("(");
+
+    emitOperand(referenced, getInfo(EmitOp::General));
+
+    m_writer->emit(")\n");
+}
+
 //
 // Expressions
 //
@@ -2029,6 +2066,10 @@ void CLikeSourceEmitter::_emitInst(IRInst* inst)
         m_writer->emit(";\n");
         break;
 
+    case kIROp_LiveRangeStart:
+    case kIROp_LiveRangeEnd:
+        emitLiveness(inst);
+        break;
     case kIROp_undefined:
     case kIROp_DefaultConstruct:
         {