[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

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@220635 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 19 deletions

diff --git a/lib/sanitizer_common/sanitizer_stacktrace.h b/lib/sanitizer_common/sanitizer_stacktrace.h
index 75ab3a06d..4ce53e494 100644
--- a/lib/sanitizer_common/sanitizer_stacktrace.h
+++ b/lib/sanitizer_common/sanitizer_stacktrace.h
@@ -30,25 +30,13 @@ static const uptr kStackTraceMax = 256;
 #endif
 
 struct StackTrace {
-  typedef bool (*SymbolizeCallback)(const void *pc, char *out_buffer,
-                                     int out_size);
-  uptr top_frame_bp;
+  const uptr *trace;
   uptr size;
-  uptr trace[kStackTraceMax];
 
-  // Prints a symbolized stacktrace, followed by an empty line.
-  static void PrintStack(const uptr *addr, uptr size);
-  void Print() const {
-    PrintStack(trace, size);
-  }
+  StackTrace(const uptr *trace, uptr size) : trace(trace), size(size) {}
 
-  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++)
-      trace[i] = src[i];
-  }
+  // Prints a symbolized stacktrace, followed by an empty line.
+  void Print() const;
 
   static bool WillUseFastUnwind(bool request_fast_unwind) {
     // Check if fast unwind is available. Fast unwind is the only option on Mac.
@@ -62,11 +50,21 @@ struct StackTrace {
     return request_fast_unwind;
   }
 
-  void Unwind(uptr max_depth, uptr pc, uptr bp, void *context, uptr stack_top,
-              uptr stack_bottom, bool request_fast_unwind);
-
   static uptr GetCurrentPc();
   static uptr GetPreviousInstructionPc(uptr pc);
+  typedef bool (*SymbolizeCallback)(const void *pc, char *out_buffer,
+                                    int out_size);
+};
+
+// StackTrace that owns the buffer used to store the addresses.
+struct BufferedStackTrace : public StackTrace {
+  uptr trace_buffer[kStackTraceMax];
+  uptr top_frame_bp;  // Optional bp of a top frame.
+
+  BufferedStackTrace() : StackTrace(trace_buffer, 0), top_frame_bp(0) {}
+
+  void Unwind(uptr max_depth, uptr pc, uptr bp, void *context, uptr stack_top,
+              uptr stack_bottom, bool request_fast_unwind);
 
  private:
   void FastUnwindStack(uptr pc, uptr bp, uptr stack_top, uptr stack_bottom,