[Sanitizer] Make StackTrace a lightweight reference to array of PCs, and

introduce a BufferedStackTrace class, which owns this array.

Summary:
This change splits __sanitizer::StackTrace class into a lightweight
__sanitizer::StackTrace, which doesn't own array of PCs, and BufferedStackTrace,
which owns it. This would allow us to simplify the interface of StackDepot,
and eventually merge __sanitizer::StackTrace with __tsan::StackTrace.

Test Plan: regression test suite.

Reviewers: kcc, dvyukov

Reviewed By: dvyukov

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5985

llvm-svn: 220635

2 files changed, 19 insertions, 23 deletions

diff --git a/compiler-rt/lib/lsan/lsan.h b/compiler-rt/lib/lsan/lsan.h
index d9dd63ab8c57..53783cdc9c7d 100644
--- a/compiler-rt/lib/lsan/lsan.h
+++ b/compiler-rt/lib/lsan/lsan.h
@@ -15,17 +15,17 @@
 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_stacktrace.h"
 
-#define GET_STACK_TRACE(max_size, fast)                                     \
-  StackTrace stack;                                                         \
-  {                                                                         \
-    uptr stack_top = 0, stack_bottom = 0;                                   \
-    ThreadContext *t;                                                       \
-    if (fast && (t = CurrentThreadContext())) {                             \
-      stack_top = t->stack_end();                                           \
-      stack_bottom = t->stack_begin();                                      \
-    }                                                                       \
-    stack.Unwind(max_size, StackTrace::GetCurrentPc(), GET_CURRENT_FRAME(), \
-                 /* context */ 0, stack_top, stack_bottom, fast);           \
+#define GET_STACK_TRACE(max_size, fast)                                        \
+  BufferedStackTrace stack;                                                    \
+  {                                                                            \
+    uptr stack_top = 0, stack_bottom = 0;                                      \
+    ThreadContext *t;                                                          \
+    if (fast && (t = CurrentThreadContext())) {                                \
+      stack_top = t->stack_end();                                              \
+      stack_bottom = t->stack_begin();                                         \
+    }                                                                          \
+    stack.Unwind(max_size, StackTrace::GetCurrentPc(), GET_CURRENT_FRAME(),    \
+                 /* context */ 0, stack_top, stack_bottom, fast);              \
   }
 
 #define GET_STACK_TRACE_FATAL \
diff --git a/compiler-rt/lib/lsan/lsan_common.cc b/compiler-rt/lib/lsan/lsan_common.cc
index a89462a729dd..ec518d7fd309 100644
--- a/compiler-rt/lib/lsan/lsan_common.cc
+++ b/compiler-rt/lib/lsan/lsan_common.cc
@@ -355,9 +355,7 @@ static void ClassifyAllChunks(SuspendedThreadsList const &suspended_threads) {
 
 static void PrintStackTraceById(u32 stack_trace_id) {
   CHECK(stack_trace_id);
-  uptr size = 0;
-  const uptr *trace = StackDepotGet(stack_trace_id, &size);
-  StackTrace::PrintStack(trace, size);
+  StackDepotGet(stack_trace_id).Print();
 }
 
 // ForEachChunk callback. Aggregates information about unreachable chunks into
@@ -372,10 +370,9 @@ static void CollectLeaksCb(uptr chunk, void *arg) {
     uptr resolution = flags()->resolution;
     u32 stack_trace_id = 0;
     if (resolution > 0) {
-      uptr size = 0;
-      const uptr *trace = StackDepotGet(m.stack_trace_id(), &size);
-      size = Min(size, resolution);
-      stack_trace_id = StackDepotPut(trace, size);
+      StackTrace stack = StackDepotGet(m.stack_trace_id());
+      uptr size = Min(stack.size, resolution);
+      stack_trace_id = StackDepotPut(stack.trace, size);
     } else {
       stack_trace_id = m.stack_trace_id();
     }
@@ -487,11 +484,10 @@ static Suppression *GetSuppressionForAddr(uptr addr) {
 }
 
 static Suppression *GetSuppressionForStack(u32 stack_trace_id) {
-  uptr size = 0;
-  const uptr *trace = StackDepotGet(stack_trace_id, &size);
-  for (uptr i = 0; i < size; i++) {
-    Suppression *s =
-        GetSuppressionForAddr(StackTrace::GetPreviousInstructionPc(trace[i]));
+  StackTrace stack = StackDepotGet(stack_trace_id);
+  for (uptr i = 0; i < stack.size; i++) {
+    Suppression *s = GetSuppressionForAddr(
+        StackTrace::GetPreviousInstructionPc(stack.trace[i]));
     if (s) return s;
   }
   return 0;