misc: add address sanitizer heap instrumentation

Introduce AddressSanitizer support: https://github.com/google/sanitizers/
This starts with heap instrumentation. vlib_buffer, bihash and stack
instrumentation should follow.

Type: feature

Change-Id: I7f20e235b2f79db72efd0e756f22c75f717a9884
Signed-off-by: Benoît Ganne <bganne@cisco.com>
diff --git a/src/svm/svm.c b/src/svm/svm.c
index 4211219..cc49eb3 100644
--- a/src/svm/svm.c
+++ b/src/svm/svm.c
@@ -61,6 +61,10 @@
 u64
 svm_get_global_region_base_va ()
 {
+#ifdef CLIB_SANITIZE_ADDR
+  return 0x200000000000;
+#endif
+
 #if __aarch64__
   /* On AArch64 VA space can have different size, from 36 to 48 bits.
      Here we are trying to detect VA bits by parsing /proc/self/maps