Fix binary spans on wrapper blocks in IRBuilder

src/passes/Print.cpp

@@ -2786,8 +2786,9 @@ void PrintSExpression::printMetadata(Expression* curr) {
       if (auto iter = currFunction->expressionLocations.find(curr);
           iter != currFunction->expressionLocations.end()) {
         Colors::grey(o);
-        o << ";; code offset: 0x" << std::hex << iter->second.start << std::dec
-          << '\n';
+        const auto& span = iter->second;
+        o << ";; code offset: 0x" << std::hex << span.start << " - 0x"
+          << span.end << std::dec << '\n';
         restoreNormalColor(o);
         doIndent(o, indent);
       }

src/wasm/wasm-ir-builder.cpp

@@ -1078,24 +1078,45 @@ Result<> IRBuilder::visitEnd() {
   auto& label = isTry ? scope.branchLabel : scope.label;
   auto blockType = scope.getResultType();
 
+  // When we wrap an expression then push the wrapper, we would end up with the
+  // binary start location attached to the original expression and the end
+  // location attached to the wrapper. Move the binary start location to the
+  // wrapper to avoid splitting the span information.
+  auto moveBinaryPosToWrapper = [&](Expression* original, Expression* wrapper) {
+    if (!func) {
+      return;
+    }
+    if (auto it = func->expressionLocations.find(original);
+        it != func->expressionLocations.end()) {
+      auto span = it->second;
+      assert(span.end == 0);
+      func->expressionLocations.erase(it);
+      [[maybe_unused]] auto [_, inserted] =
+        func->expressionLocations.insert({wrapper, span});
+      assert(inserted);
+    }
+  };
+
   // If the scope expression cannot be directly labeled, we may need to wrap it
   // in a block.
   auto maybeWrapForLabel = [&](Expression* curr) -> Expression* {
     if (!label) {
       return curr;
     }
-    curr = fixExtraOutput(scope, label, curr);
+    auto* fixed = fixExtraOutput(scope, label, curr);
     // We can re-use unnamed blocks instead of wrapping them.
-    if (auto* block = curr->dynCast<Block>(); block && !block->name) {
+    if (auto* block = fixed->dynCast<Block>(); block && !block->name) {
       block->name = label;
       block->type = blockType;
+      moveBinaryPosToWrapper(curr, block);
       return block;
     }
     auto* block = builder.makeBlock();
     block->name = label;
-    block->list.push_back(curr);
+    block->list.push_back(fixed);
     block->finalize(blockType,
                     scope.labelUsed ? Block::HasBreak : Block::NoBreak);
+    moveBinaryPosToWrapper(curr, block);
     return block;
   };
 

test/lit/debug/control-flow-wrappers.test

@@ -0,0 +1,73 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; Regression test for a bug in IRBuilder would assign end offsets incorrectly
+;; when control flow structures required wrapping.
+
+;; RUN: env BINARYEN_PRINT_FULL=1 wasm-opt %s.wasm -all --debuginfo --print -o /dev/null | filecheck %s
+
+;; Test module generated with `wasm-tools parse` on the following wat:
+;; (module
+;;   ;; Add a dummy DWARF section so the parser will collect code offsets.
+;;   (@custom ".debug_info" "")
+;;   (tag $e)
+;;   (func
+;;     ;; The end offset would never be set because it would be assigned to the
+;;     ;; wrapper block instead.
+;;     try
+;;       br 0
+;;     catch $e
+;;     end
+;;     ;; Same here. Two instructions having the same end offset (0) would cause an
+;;     ;; assertion failure.
+;;     try
+;;       br 0
+;;     catch $e
+;;     end
+;;   )
+;; )
+
+;; CHECK:      (type $0 (func))
+
+;; CHECK:      (tag $e (type $0))
+
+;; CHECK:      (func $0 (type $0) (; (ref (exact $func.0)) ;)
+;; CHECK-NEXT:  ;;@
+;; CHECK-NEXT:  (block (; none ;)
+;; CHECK-NEXT:   ;;@
+;; CHECK-NEXT:   ;; code offset: 0x3 - 0xa
+;; CHECK-NEXT:   (block $label (; none ;)
+;; CHECK-NEXT:    ;;@
+;; CHECK-NEXT:    (try
+;; CHECK-NEXT:     (do
+;; CHECK-NEXT:      ;;@
+;; CHECK-NEXT:      ;; code offset: 0x5 - 0x7
+;; CHECK-NEXT:      (br $label) (; unreachable ;)
+;; CHECK-NEXT:     )
+;; CHECK-NEXT:     ;; code offset: 0x7
+;; CHECK-NEXT:     (catch $e
+;; CHECK-NEXT:      ;;@
+;; CHECK-NEXT:      (block (; none ;)
+;; CHECK-NEXT:      ) ;; end block (; none ;)
+;; CHECK-NEXT:     )
+;; CHECK-NEXT:    ) ;; end try (; none ;)
+;; CHECK-NEXT:   ) ;; end block label
+;; CHECK-NEXT:   ;;@
+;; CHECK-NEXT:   ;; code offset: 0xa - 0x11
+;; CHECK-NEXT:   (block $label1 (; none ;)
+;; CHECK-NEXT:    ;;@
+;; CHECK-NEXT:    (try
+;; CHECK-NEXT:     (do
+;; CHECK-NEXT:      ;;@
+;; CHECK-NEXT:      ;; code offset: 0xc - 0xe
+;; CHECK-NEXT:      (br $label1) (; unreachable ;)
+;; CHECK-NEXT:     )
+;; CHECK-NEXT:     ;; code offset: 0xe
+;; CHECK-NEXT:     (catch $e
+;; CHECK-NEXT:      ;;@
+;; CHECK-NEXT:      (block (; none ;)
+;; CHECK-NEXT:      ) ;; end block (; none ;)
+;; CHECK-NEXT:     )
+;; CHECK-NEXT:    ) ;; end try (; none ;)
+;; CHECK-NEXT:   ) ;; end block label1 (; none ;)
+;; CHECK-NEXT:  ) ;; end block (; none ;)
+;; CHECK-NEXT: )