[esan] Intercept and chain signal handlers
Summary:
In preparation for fault-based shadow memory iteration, we add support for
our own signal handler by adding app signal handler interception as well as
chaining for SIGSEGV. This is done in a simple manner: we do not honor the
app's alternate stack nor any sigaction flags for SIGSEGV.
Adds a new test of transparency in app signal handling.
Reviewers: aizatsky
Subscribers: filcab, kubabrecka, vitalybuka, zhaoqin, kcc, eugenis, llvm-commits
Differential Revision: http://reviews.llvm.org/D20577
llvm-svn: 271272
8 files changed