Comments

Author: vouillon

src/passes/Print.cpp

@@ -117,6 +117,11 @@ struct PrintSExpression : public UnifiedExpressionVisitor<PrintSExpression> {
 
   Module* currModule = nullptr;
   Function* currFunction = nullptr;
+  // Keep track of the last printed debug location to avoid printing
+  // repeated debug locations for children. nullopt means that we have
+  // not yet printed any debug location, or that we last printed an
+  // annotation indicating that the expression had not associated
+  // debug location.
   std::optional<Function::DebugLocation> lastPrintedLocation;
   bool debugInfo;
 

src/wasm-ir-builder.h

@@ -238,6 +238,12 @@ class IRBuilder : public UnifiedExpressionVisitor<IRBuilder, Result<>> {
   Module& wasm;
   Function* func;
   Builder builder;
+  // We distinguish three cases:
+  // - no debug location has been specified for the next instruction;
+  //   then this instruction may inherit a debug location from its
+  //   parent or a previous sibling;
+  // - we explicitly specified that this instruction has no debug location;
+  // - we provided a debug location for this instruction.
   std::optional<std::optional<Function::DebugLocation>> debugLoc;
 
   struct ChildPopper;