429534 - Treehydra: objects with null tree code appearing in dehydra-types conversions

Status: RESOLVED FIXED

(Developer Infrastructure :: Source Code Analysis, defect)

Description

[David Mandelin [:dmandelin]]

This bug applies to the dehydra_types library, which is JS that converts Treehydra types to Dehydra types. 

We're currently getting a JS exception in running static-analysis.js in Treehydra on nsArrayEnumerator.cpp from mozilla-central as of 16 April. This is using Treehydra as of 16 April, changeset af819f44b59a (adding instrumentation). The immediate cause of the exception is a Treehydra object with TREE_CODE (.base.code) of null, which causes failures in many treehydra.js lib functions. These null values are very surprising, so it really needs to be figured out.

Comment 1

[(dormant account)]

You are getting a null because types aren't always tree_nodes :)

It's probably a lang_tree_node. Types can have language-specific stuff in them. GCC does weird things with the tree_code stuff, so I haven't yet made treehydra support C++-specific tree codes.

One should probably fix convert_tree.js to output an integer when an enum can not be produced. That'd be much easier to diagnose.

Comment 2

[David Mandelin [:dmandelin]]

I think it is a tree node, but I definitely agree that those nulls are very bad. Beyond debuggability, the library code can't handle them.

I changed the code generator so it returns a dummy Treehydra enum and prints a warning that includes the real name of the tree code. It turns out all the nodes causing problems for the test case here are TEMPLATE_DECLs.

Comment 3

[(dormant account)]

They are indeed tree nodes.
TEMPLATE_DECL afaik is not defined in the middleend by default :) I'd be against returning bogus nodes and would rather have code fail when it hits funny enums.

For now you can use cp_tree_code type instead of tree_code. We'll have to figure out how to separate C stuff from C++ later.

Comment 4

[(dormant account)]

Adding this to my queue

Comment 5

[(dormant account)]

same fix as for 427661