[ASan] Do not rely on malloc context in allocator reports.

Invoke a fatal stack trace unwinder when ASan prints allocator-relevant
error reports (double-free, alloc-dealloc-mismatch, invalid-free).
Thus we'll be able to print complete stack trace even if allocation/free
stacks are not stored (malloc_context_size=0).

Based on the patch by Yuri Gribov!


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@194579 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 5 insertions, 0 deletions

diff --git a/lib/sanitizer_common/sanitizer_stacktrace.h b/lib/sanitizer_common/sanitizer_stacktrace.h
index 408063c18..88f0a03b1 100644
--- a/lib/sanitizer_common/sanitizer_stacktrace.h
+++ b/lib/sanitizer_common/sanitizer_stacktrace.h
@@ -33,6 +33,7 @@ static const uptr kStackTraceMax = 256;
 struct StackTrace {
   typedef bool (*SymbolizeCallback)(const void *pc, char *out_buffer,
                                      int out_size);
+  uptr top_frame_bp;
   uptr size;
   uptr trace[kStackTraceMax];
 
@@ -41,6 +42,7 @@ struct StackTrace {
                          SymbolizeCallback symbolize_callback = 0);
 
   void CopyFrom(const uptr *src, uptr src_size) {
+    top_frame_bp = 0;
     size = src_size;
     if (size > kStackTraceMax) size = kStackTraceMax;
     for (uptr i = 0; i < size; i++)
diff --git a/lib/sanitizer_common/sanitizer_stacktrace_libcdep.cc b/lib/sanitizer_common/sanitizer_stacktrace_libcdep.cc
index a8e70c965..58fa18251 100644
--- a/lib/sanitizer_common/sanitizer_stacktrace_libcdep.cc
+++ b/lib/sanitizer_common/sanitizer_stacktrace_libcdep.cc
@@ -21,6 +21,8 @@ void StackTrace::Unwind(uptr max_depth, uptr pc, uptr bp, uptr stack_top,
     SlowUnwindStack(pc, max_depth);
   else
     FastUnwindStack(pc, bp, stack_top, stack_bottom, max_depth);
+
+  top_frame_bp = size ? bp : 0;
 }
 
 }  // namespace __sanitizer
diff --git a/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc b/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc
index 5e6d3fdbd..2b842cd81 100644
--- a/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc
+++ b/lib/sanitizer_common/tests/sanitizer_stacktrace_test.cc
@@ -99,6 +99,7 @@ TEST_F(FastUnwindTest, OneFrameStackTrace) {
     return;
   EXPECT_EQ(1U, trace.size);
   EXPECT_EQ(start_pc, trace.trace[0]);
+  EXPECT_EQ((uptr)&fake_stack[0], trace.top_frame_bp);
 }
 
 }  // namespace __sanitizer