Source maps: Allow specifying that an expression has no debug info in text (#6520)

;;@

with nothing else (no source:line) can be used to specify that the following
expression does not have any debug info associated to it. This can be used
to stop the automatic propagation of debug info in the text parsers.

The text printer has also been updated to output this comment when needed.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/wasm.h b/src/wasm.h
index 2f3f09ad5..dd7164499 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -2167,7 +2167,9 @@ public:
                    : columnNumber < other.columnNumber;
     }
   };
-  std::unordered_map<Expression*, DebugLocation> debugLocations;
+  // One can explicitly set the debug location of an expression to
+  // nullopt to stop the propagation of debug locations.
+  std::unordered_map<Expression*, std::optional<DebugLocation>> debugLocations;
   std::set<DebugLocation> prologLocation;
   std::set<DebugLocation> epilogLocation;