Warn about and ignore empty local/param names in name section (#4426)

Fixes the crash in #4418

Also replace the .at() there with better logic to handle imported functions.

See WebAssembly/wabt#1799 for details on why wabt sometimes emits this.

2 files changed, 14 insertions, 0 deletions

diff --git a/test/lit/binary/empty-param-name.test b/test/lit/binary/empty-param-name.test
new file mode 100644
index 000000000..2216d0bbb
--- /dev/null
+++ b/test/lit/binary/empty-param-name.test
@@ -0,0 +1,14 @@
+;; Test that we show a warning on an empty local name, and do not crash.
+;;
+;; The binary contains this, processed by wabt with debug names:
+;;
+;;   (module
+;;     (func $foo (import "imports" "foo") (param i32)))
+;;
+;; Wabt emits a name for that parameter, but it is the empty string. See
+;; https://github.com/WebAssembly/wabt/issues/1799
+
+;; RUN: wasm-opt %s.wasm 2>&1 | filecheck %s
+
+;; CHECK: warning: empty local name at index 0 in function foo
+
diff --git a/test/lit/binary/empty-param-name.test.wasm b/test/lit/binary/empty-param-name.test.wasm
new file mode 100644
index 000000000..6d08ab93a
--- /dev/null
+++ b/test/lit/binary/empty-param-name.test.wasm