[sanitizer] Port fast stack unwinder to sparcv8

Differential Revision: https://reviews.llvm.org/D46469

llvm-svn: 332046

compiler-rt/lib/sanitizer_common/CMakeLists.txt

@@ -72,6 +72,7 @@ set(SANITIZER_SYMBOLIZER_SOURCES
   sanitizer_stacktrace.cc
   sanitizer_stacktrace_libcdep.cc
   sanitizer_stacktrace_printer.cc
+  sanitizer_stacktrace_sparc.cc
   sanitizer_symbolizer.cc
   sanitizer_symbolizer_fuchsia.cc
   sanitizer_symbolizer_libbacktrace.cc

compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.cc

@@ -20,7 +20,7 @@ namespace __sanitizer {
 uptr StackTrace::GetNextInstructionPc(uptr pc) {
 #if defined(__mips__)
   return pc + 8;
-#elif defined(__powerpc__)
+#elif defined(__powerpc__) || defined(__sparc__)
   return pc + 4;
 #else
   return pc + 1;
@@ -40,6 +40,9 @@ void BufferedStackTrace::Init(const uptr *pcs, uptr cnt, uptr extra_top_pc) {
   top_frame_bp = 0;
 }
 
+// Sparc implemention is in its own file.
+#if !defined(__sparc__)
+
 // In GCC on ARM bp points to saved lr, not fp, so we should check the next
 // cell in stack to be a saved frame pointer. GetCanonicFrame returns the
 // pointer to saved frame pointer in any case.
@@ -106,6 +109,8 @@ void BufferedStackTrace::FastUnwindStack(uptr pc, uptr bp, uptr stack_top,
   }
 }
 
+#endif  // !defined(__sparc__)
+
 void BufferedStackTrace::PopStackFrames(uptr count) {
   CHECK_LT(count, size);
   size -= count;

compiler-rt/lib/sanitizer_common/sanitizer_stacktrace_sparc.cc

@@ -0,0 +1,58 @@
+//===-- sanitizer_stacktrace_sparc.cc -------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is shared between AddressSanitizer and ThreadSanitizer
+// run-time libraries.
+//
+// Implemention of fast stack unwinding for Sparc.
+//===----------------------------------------------------------------------===//
+
+// This file is ported to Sparc v8, but it should be easy to port to
+// Sparc v9.
+#if defined(__sparcv8__)
+
+#include "sanitizer_common.h"
+#include "sanitizer_stacktrace.h"
+
+namespace __sanitizer {
+
+void BufferedStackTrace::FastUnwindStack(uptr pc, uptr bp, uptr stack_top,
+                                         uptr stack_bottom, u32 max_depth) {
+  const uptr kPageSize = GetPageSizeCached();
+  CHECK_GE(max_depth, 2);
+  trace_buffer[0] = pc;
+  size = 1;
+  if (stack_top < 4096) return;  // Sanity check for stack top.
+  // Flush register windows to memory
+  asm volatile("ta 3" ::: "memory");
+  uhwptr *frame = (uhwptr*)bp;
+  // Lowest possible address that makes sense as the next frame pointer.
+  // Goes up as we walk the stack.
+  uptr bottom = stack_bottom;
+  // Avoid infinite loop when frame == frame[0] by using frame > prev_frame.
+  while (IsValidFrame((uptr)frame, stack_top, bottom) &&
+         IsAligned((uptr)frame, sizeof(*frame)) &&
+         size < max_depth) {
+    uhwptr pc1 = frame[15];
+    // Let's assume that any pointer in the 0th page is invalid and
+    // stop unwinding here.  If we're adding support for a platform
+    // where this isn't true, we need to reconsider this check.
+    if (pc1 < kPageSize)
+      break;
+    if (pc1 != pc) {
+      trace_buffer[size++] = (uptr) pc1;
+    }
+    bottom = (uptr)frame;
+    frame = (uhwptr*)frame[14];
+  }
+}
+
+}  // namespace __sanitizer
+
+#endif  // !defined(__sparcv8__)