[MSan] [PowerPC] Dereference function descriptors when recording stack origins.

Differential Revision: http://reviews.llvm.org/D19543

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@267795 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/msan/msan.cc b/lib/msan/msan.cc
index 52eda77e6..d2981f0b0 100644
--- a/lib/msan/msan.cc
+++ b/lib/msan/msan.cc
@@ -538,6 +538,13 @@ void __msan_set_alloca_origin4(void *a, uptr size, char *descr, uptr pc) {
     u32 idx = atomic_fetch_add(&NumStackOriginDescrs, 1, memory_order_relaxed);
     CHECK_LT(idx, kNumStackOriginDescrs);
     StackOriginDescr[idx] = descr + 4;
+#if SANITIZER_PPC64V1
+    // On PowerPC64 ELFv1, the address of a function actually points to a
+    // three-doubleword data structure with the first field containing
+    // the address of the function's code.
+    if (pc)
+      pc = *reinterpret_cast<uptr*>(pc);
+#endif
     StackOriginPC[idx] = pc;
     id = Origin::CreateStackOrigin(idx).raw_id();
     *id_ptr = id;