This change allows a WasmObjectFile to be created from a wasm file even
if it uses typed funcrefs and GC types. It does not significantly change how
lib/Object models its various internal types (e.g. WasmSignature,
WasmElemSegment), so LLVM does not really "support" or understand such
files, but it is sufficient to parse the type, global and element sections, discarding
types that are not understood. This is useful for low-level binary tools such as
nm and objcopy, which use only limited aspects of the binary (such as function
definitions) or deal with sections as opaque blobs.
This is done by allowing `WasmValType` to have a value of `OTHERREF`
(representing any unmodeled reference type), and adding a field to
`WasmSignature` indicating it's a placeholder for an unmodeled reference
type (since there is a 1:1 correspondence between WasmSignature objects
and types in the type section).
Then the object file parsers for the type and element sections are expanded
to parse encoded reference types and discard any unmodeled fields.
Summary:
This patch checks if the section order is correct when reading a wasm
object file in `WasmObjectFile` and converting YAML to wasm object in
yaml2wasm. (It is not possible to check when reading YAML because it is
handled exclusively by the YAML reader.)
This checks the ordering of all known sections (core sections + known
custom sections). This also adds section ID DataCount section that will
be scheduled to be added in near future.
Reviewers: sbc100
Subscribers: dschuff, mgorny, jgravelle-google, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D54924
llvm-svn: 349221
When reading a custom WASM section, it was possible that its name
extended beyond the size of the section. This resulted in a bogus value
for the section size due to the size overflowing.
Fixes heap buffer overflow detected by OSS-fuzz:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=8190
Differential revision: https://reviews.llvm.org/D50387
llvm-svn: 339269
