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

3 files changed, 1 insertions, 0 deletions

diff --git a/test/passes/dwarf_unit_with_no_abbrevs_noprint.bin.txt b/test/passes/dwarf_unit_with_no_abbrevs_noprint.bin.txt
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/test/passes/dwarf_unit_with_no_abbrevs_noprint.bin.txt
diff --git a/test/passes/dwarf_unit_with_no_abbrevs_noprint.passes b/test/passes/dwarf_unit_with_no_abbrevs_noprint.passes
new file mode 100644
index 000000000..48ea00769
--- /dev/null
+++ b/test/passes/dwarf_unit_with_no_abbrevs_noprint.passes
@@ -0,0 +1 @@
+roundtrip_g
diff --git a/test/passes/dwarf_unit_with_no_abbrevs_noprint.wasm b/test/passes/dwarf_unit_with_no_abbrevs_noprint.wasm
new file mode 100644
index 000000000..bf50db775
--- /dev/null
+++ b/test/passes/dwarf_unit_with_no_abbrevs_noprint.wasm