[sanitizer][esan] Add internal_sigaction_syscall

Summary:
Adds a version of sigaction that uses a raw system call, to avoid circular
dependencies and support calling sigaction prior to setting up
interceptors.  The new sigaction relies on an assembly sigreturn routine
for its restorer, which is Linux x86_64-only for now.

Uses the new sigaction to initialize the working set tool's shadow fault
handler prior to libc interceptor being set up.  This is required to
support instrumentation invoked during interceptor setup, which happens
with an instrumented tcmalloc or other allocator compiled with esan.

Adds a test that emulates an instrumented allocator.

Reviewers: aizatsky

Subscribers: vitalybuka, tberghammer, zhaoqin, danalbert, kcc, srhines, eugenis, llvm-commits, kubabrecka

Differential Revision: http://reviews.llvm.org/D21083

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@272676 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 0 deletions

diff --git a/lib/esan/esan.cpp b/lib/esan/esan.cpp
index e7399e219..e6d6aff31 100644
--- a/lib/esan/esan.cpp
+++ b/lib/esan/esan.cpp
@@ -197,6 +197,9 @@ void initializeLibrary(ToolType Tool) {
   }
 
   initializeShadow();
+  if (__esan_which_tool == ESAN_WorkingSet)
+    initializeShadowWorkingSet();
+
   initializeInterceptors();
 
   if (__esan_which_tool == ESAN_CacheFrag) {