ucrtbase.dll appears to be built with some kind of cross-module
inlining, because there are calls to imported Heap* routines sprinkled
throughout the code. This inlining defeats our attempts to hotpatch
malloc, _malloc_base, and related functions. Failing to intercept an
allocation or deallocation results in a crash when the program attempts
to deallocate or reallocate memory with the wrong allocator.
This change patches the IAT of ucrtbase.dll to replace the addresses of
the imported Heap* functions with implementations provided by ASan. We
don't globally intercept the win32 Heap* functions because they are
typically used by system DLLs that run before ASan initializes.
Eventually, we may want to intercept them, but for now I think this is
the minimal change that will keep ASan stable.
Reviewers: samsonov
Differential Revision: http://reviews.llvm.org/D18413
llvm-svn: 264327
ASan uses GetProcAddress to get the address of malloc so it can patch
it. Newer versions of Windows make GetProcAddress initialize the DLL
before returning a function pointer into it. That's perfectly
reasonable, but ASan needs to finish patching malloc before CRT
initialization. So now we roll our own GetProcAddress.
Fixes PR24237
Based on a patch by David Major
Originally written by David Major as part of:
https://hg.mozilla.org/mozilla-central/file/tip/toolkit/xre/WindowsCrtPatch.h
llvm-svn: 245377
Reid Kleckner