DWARF: Ignore a compile unit with no abbreviations (#2678)

Such a module can't have valid DIEs, since we have no way to
interpret them.

Also check if DWARF sections from LLVM have contents -
when they are empty the section may exist but have a null
for its data.

Fixes #2673

1 files changed, 1 insertions, 1 deletions

diff --git a/src/wasm/wasm-debug.cpp b/src/wasm/wasm-debug.cpp
index 50a04a6e6..286b63e69 100644
--- a/src/wasm/wasm-debug.cpp
+++ b/src/wasm/wasm-debug.cpp
@@ -56,7 +56,7 @@ struct BinaryenDWARFInfo {
   BinaryenDWARFInfo(const Module& wasm) {
     // Get debug sections from the wasm.
     for (auto& section : wasm.userSections) {
-      if (Name(section.name).startsWith(".debug_")) {
+      if (Name(section.name).startsWith(".debug_") && section.data.data()) {
         // TODO: efficiency
         sections[section.name.substr(1)] = llvm::MemoryBuffer::getMemBufferCopy(
           llvm::StringRef(section.data.data(), section.data.size()));