[NFC] Encapsulate source map reader state (#7132)

Move all state relevant to reading source maps out of WasmBinaryReader
and into a new utility, SourceMapReader. This is a prerequisite for
parallelizing the parsing of function bodies, since the source map
reader state is different at the beginning of each function.

Also take the opportunity to simplify the way we read source maps, for
example by deferring the reading of anything but the position of a debug
location until it will be used and by using `std::optional` instead of
singleton `std::set`s to store function prologue and epilogue debug
locations.

1 files changed, 0 insertions, 9 deletions

diff --git a/src/parsing.h b/src/parsing.h
index d59b3bd7c..80d4db9fb 100644
--- a/src/parsing.h
+++ b/src/parsing.h
@@ -43,15 +43,6 @@ struct ParseException {
   void dump(std::ostream& o) const;
 };
 
-struct MapParseException {
-  std::string text;
-
-  MapParseException() : text("unknown parse error") {}
-  MapParseException(std::string text) : text(text) {}
-
-  void dump(std::ostream& o) const;
-};
-
 // Helper for parsers that may not have unique label names. This transforms
 // the names into unique ones, as required by Binaryen IR.
 struct UniqueNameMapper {