Merge pull request #58410 from gottesmm/move-function-dbg-info-dataflow

[debug-info] Implement a global dataflow that propagates debug info for async vars and clones the dbg info after funclet points.

Author: gottesmm

include/swift/SIL/DebugUtils.h

@@ -237,24 +237,26 @@ bool hasNonTrivialNonDebugTransitiveUsers(
 /// operators to access functionality from the underlying instruction when
 /// needed.
 struct DebugVarCarryingInst {
-  enum class Kind {
+  enum class Kind : uint8_t {
     Invalid = 0,
     DebugValue,
     AllocStack,
     AllocBox,
   };
 
-  Kind kind;
   SILInstruction *inst;
+  Kind kind;
+  uintptr_t spareBits : (sizeof(uintptr_t) - sizeof(Kind)) * 8;
 
-  DebugVarCarryingInst() : kind(Kind::Invalid), inst(nullptr) {}
+  DebugVarCarryingInst() : inst(nullptr), kind(Kind::Invalid), spareBits(0) {}
   DebugVarCarryingInst(DebugValueInst *dvi)
-      : kind(Kind::DebugValue), inst(dvi) {}
+      : inst(dvi), kind(Kind::DebugValue), spareBits(0) {}
   DebugVarCarryingInst(AllocStackInst *asi)
-      : kind(Kind::AllocStack), inst(asi) {}
-  DebugVarCarryingInst(AllocBoxInst *abi) : kind(Kind::AllocBox), inst(abi) {}
+      : inst(asi), kind(Kind::AllocStack), spareBits(0) {}
+  DebugVarCarryingInst(AllocBoxInst *abi)
+      : inst(abi), kind(Kind::AllocBox), spareBits(0) {}
   DebugVarCarryingInst(SILInstruction *newInst)
-      : kind(Kind::Invalid), inst(nullptr) {
+      : inst(nullptr), kind(Kind::Invalid), spareBits(0) {
     switch (newInst->getKind()) {
     default:
       return;
@@ -280,6 +282,15 @@ struct DebugVarCarryingInst {
   /// '->'. This keeps the wrapper light weight.
   SILInstruction *operator->() const { return inst; }
 
+  bool operator==(const DebugVarCarryingInst &other) const {
+    return kind == other.kind && inst == other.inst &&
+           spareBits == other.spareBits;
+  }
+
+  bool operator!=(const DebugVarCarryingInst &other) const {
+    return !(*this == other);
+  }
+
   /// Add support for this struct in `if` statement.
   explicit operator bool() const { return bool(kind); }
 
@@ -351,7 +362,8 @@ struct DebugVarCarryingInst {
     case Kind::AllocStack:
       return cast<AllocStackInst>(inst)->getWasMoved();
     case Kind::AllocBox:
-      llvm_unreachable("Not implemented");
+      // We do not support moving alloc box today, so we always return false.
+      return false;
     }
   }
 

include/swift/SILOptimizer/PassManager/Passes.def

@@ -448,6 +448,8 @@ PASS(DebugInfoCanonicalizer, "sil-onone-debuginfo-canonicalizer",
      "Canonicalize debug info at -Onone by propagating debug info into coroutine funclets")
 PASS(PartialApplySimplification, "partial-apply-simplification",
      "Transform partial_apply instructions into explicit closure box constructions")
+PASS(MovedAsyncVarDebugInfoPropagator, "sil-moved-async-var-dbginfo-propagator",
+     "Propagate debug info from moved async vars after coroutine funclet boundaries")
 PASS(PruneVTables, "prune-vtables",
      "Mark class methods that do not require vtable dispatch")
 PASS_RANGE(AllPasses, AADumper, PruneVTables)

lib/SILOptimizer/Mandatory/CMakeLists.txt

@@ -21,6 +21,7 @@ target_sources(swiftSILOptimizer PRIVATE
   LexicalLifetimeEliminator.cpp
   LowerHopToActor.cpp
   MandatoryInlining.cpp
+  MovedAsyncVarDebugInfoPropagator.cpp
   MoveFunctionCanonicalization.cpp
   MoveKillsCopyableAddressesChecker.cpp
   MoveKillsCopyableValuesChecker.cpp