Inliner optimizatin deletes Functions even if there are pointers to them in the stub->function map

[nunoplopes]

Bugzilla Link	2666
Resolution	INVALID
Resolved on	Aug 11, 2008 18:16
Version	trunk
OS	All
Attachments	test case

Extended Description

The inliner optimization deletes internal functions that were inlined. The problem is that the JIT engine may still have references to such functions, in particular there might be some code in memory that references such functions (via stubs).
This bug is easy to trigger. I'll attach a simple test case.

The zip file contains the following:

• module.c/bc - a module with 2 little functions to be loaded at runtime.
  you may need to regenerate the .bc file with e.g. clang. I've compiled it in a
  linux/x86 machine
• jitbug.cpp - the test case itself. comment line 49 (i.e. disable the inliner) to make the test pass.
• compile.sh - a one-linner to compile the jitbug.cpp file

to run the test, just type ./test.

[lattner]

This is 'behaves correctly'. To avoid this behavior, you should change the linkage of functions to "external" if the jit has a reference to them. This will prevent the inliner from deleting them. We can't have the inliner know about the JIT or the JIT know about the inliner.