Fix name deduplication with partial names sections (#5689)

We already deduplicated names in the names section (to defend against a weird
binary), but we also need to deduplicate the names of items not in the names
section, so they don't overlap with the names that are. See example in the testcase.

Normally wasm files use names for all items in each group. This only became
noticeable in some wasm-ctor-eval work where new temp globals were added
that were not given names.

1 files changed, 22 insertions, 0 deletions

diff --git a/test/lit/binary/name-overlap.test b/test/lit/binary/name-overlap.test
new file mode 100644
index 000000000..7f5318737
--- /dev/null
+++ b/test/lit/binary/name-overlap.test
@@ -0,0 +1,22 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+;; RUN: wasm-opt %s.wasm -S -o - | filecheck %s
+
+;; Test that we emit deduplicated names even in the corner case that one item
+;; is in the names section and the other is not, and the latter's temp name
+;; coincides with the name the name section gives for the first. Specifically,
+;; the input wasm looks like this:
+;;
+;;  (module
+;;   (global $global$1 i32 (i32.const 1)) ;; In names section.
+;;   (global $........ i32 (i32.const 0)) ;; *Not* in names section.
+;;  )
+;;
+;; We give them temp names $global$0, $global$1 to begin with, then apply the
+;; names section which turns the first's name into $global$1 - identical to the
+;; second. We must then deduplicate the second name to avoid a collision. (Note
+;; that we leave the name from the names section as it is, and only adjust the
+;; temp name.)
+
+;; CHECK:       (global $global$1 i32 (i32.const 1))
+;; CHECK-NEXT:  (global $global$1.1 i32 (i32.const 0))
+