1 files changed, 31 insertions, 29 deletions

diff --git a/compiler-rt/lib/asan/asan_report.cc b/compiler-rt/lib/asan/asan_report.cc
index d77be3275b2..713e115a0b6 100644
--- a/compiler-rt/lib/asan/asan_report.cc
+++ b/compiler-rt/lib/asan/asan_report.cc
@@ -381,9 +381,14 @@ void PrintAccessAndVarIntersection(const char *var_name,
 
 bool ParseFrameDescription(const char *frame_descr,
                            InternalMmapVector<StackVarDescr> *vars) {
+  CHECK(frame_descr);
   char *p;
+  // This string is created by the compiler and has the following form:
+  // "n alloc_1 alloc_2 ... alloc_n"
+  // where alloc_i looks like "offset size len ObjectName".
   uptr n_objects = (uptr)internal_simple_strtoll(frame_descr, &p, 10);
-  CHECK_GT(n_objects, 0);
+  if (n_objects == 0)
+    return false;
 
   for (uptr i = 0; i < n_objects; i++) {
     uptr beg  = (uptr)internal_simple_strtoll(p, &p, 10);
@@ -404,31 +409,21 @@ bool ParseFrameDescription(const char *frame_descr,
 bool DescribeAddressIfStack(uptr addr, uptr access_size) {
   AsanThread *t = FindThreadByStackAddress(addr);
   if (!t) return false;
-  const uptr kBufSize = 4095;
-  char buf[kBufSize];
-  uptr offset = 0;
-  uptr frame_pc = 0;
-  char tname[128];
-  const char *frame_descr = t->GetFrameNameByAddr(addr, &offset, &frame_pc);
 
-#ifdef __powerpc64__
-  // On PowerPC64, 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.
-  frame_pc = *reinterpret_cast<uptr *>(frame_pc);
-#endif
-
-  // This string is created by the compiler and has the following form:
-  // "n alloc_1 alloc_2 ... alloc_n"
-  // where alloc_i looks like "offset size len ObjectName ".
-  CHECK(frame_descr);
   Decorator d;
+  char tname[128];
   Printf("%s", d.Location());
-  Printf("Address %p is located in stack of thread T%d%s "
-         "at offset %zu in frame\n",
-         addr, t->tid(),
-         ThreadNameWithParenthesis(t->tid(), tname, sizeof(tname)),
-         offset);
+  Printf("Address %p is located in stack of thread T%d%s", addr, t->tid(),
+         ThreadNameWithParenthesis(t->tid(), tname, sizeof(tname)));
+
+  // Try to fetch precise stack frame for this access.
+  AsanThread::StackFrameAccess access;
+  if (!t->GetStackFrameAccessByAddr(addr, &access)) {
+    Printf("%s\n", d.EndLocation());
+    return true;
+  }
+  Printf(" at offset %zu in frame%s\n", access.offset, d.EndLocation());
+
   // Now we print the frame where the alloca has happened.
   // We print this frame as a stack trace with one element.
   // The symbolizer may print more than one frame if inlining was involved.
@@ -437,15 +432,21 @@ bool DescribeAddressIfStack(uptr addr, uptr access_size) {
   // especially given that the alloca may be from entirely different place
   // (e.g. use-after-scope, or different thread's stack).
   StackTrace alloca_stack;
-  alloca_stack.trace[0] = frame_pc + 16;
+#ifdef __powerpc64__
+  // On PowerPC64, 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.
+  access.frame_pc = *reinterpret_cast<uptr *>(access.frame_pc);
+#endif
+  alloca_stack.trace[0] = access.frame_pc + 16;
   alloca_stack.size = 1;
   Printf("%s", d.EndLocation());
   alloca_stack.Print();
 
   InternalMmapVector<StackVarDescr> vars(16);
-  if (!ParseFrameDescription(frame_descr, &vars)) {
+  if (!ParseFrameDescription(access.frame_descr, &vars)) {
     Printf("AddressSanitizer can't parse the stack frame "
-           "descriptor: |%s|\n", frame_descr);
+           "descriptor: |%s|\n", access.frame_descr);
     // 'addr' is a stack address, so return true even if we can't parse frame
     return true;
   }
@@ -454,15 +455,16 @@ bool DescribeAddressIfStack(uptr addr, uptr access_size) {
   Printf("  This frame has %zu object(s):\n", n_objects);
 
   // Report all objects in this frame.
+  const uptr kBufSize = 4095;
+  char buf[kBufSize];
   for (uptr i = 0; i < n_objects; i++) {
     buf[0] = 0;
     internal_strncat(buf, vars[i].name_pos,
                      static_cast<uptr>(Min(kBufSize, vars[i].name_len)));
     uptr prev_var_end = i ? vars[i - 1].beg + vars[i - 1].size : 0;
     uptr next_var_beg = i + 1 < n_objects ? vars[i + 1].beg : ~(0UL);
-    PrintAccessAndVarIntersection(buf, vars[i].beg, vars[i].size,
-                                  offset, access_size,
-                                  prev_var_end, next_var_beg);
+    PrintAccessAndVarIntersection(buf, vars[i].beg, vars[i].size, access.offset,
+                                  access_size, prev_var_end, next_var_beg);
   }
   Printf("HINT: this may be a false positive if your program uses "
          "some custom stack unwind mechanism or swapcontext\n");