Add an API function to get a debugger stack trace from an error handle.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index ebece8a43d8a8aa9d856d7cc0d167961eb00332d..eab8fc5782297747a9b577214ba4bda4d409cba2 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -15568,6 +15568,82 @@ const char* Stacktrace::ToCStringInternal(intptr_t* frame_index) const {
 }
 
 
+ExceptionStackTrace* Stacktrace::BuildExceptionStackTrace() const {
+  ExceptionStackTrace* result = new ExceptionStackTrace(8);
+  String& function_name = String::Handle();
+  String& script_uri = String::Handle();
+  Script& script = Script::Handle();
+
+  Function& function = Function::Handle();
+  Code& code = Code::Handle();
+  for (intptr_t i = 0; i < Length(); i++) {
+    function = FunctionAtFrame(i);
+    if (function.IsNull()) {
+      // Check if null function object indicates a stack trace overflow.
+      if ((i < (Length() - 1)) &&
+          (FunctionAtFrame(i + 1) != Function::null())) {
+        function_name = Symbols::Empty().raw();
+        script_uri = Symbols::Empty().raw();
+        intptr_t line = -1;
+        intptr_t column = -1;
+        result->AddFrame(
+            new ExceptionStackFrame(function_name, script_uri, line, column));
+      }
+    } else if (function.is_visible()) {
+      code = CodeAtFrame(i);
+      ASSERT(function.raw() == code.function());
+      uword pc = code.EntryPoint() + Smi::Value(PcOffsetAtFrame(i));
+      if (code.is_optimized() && expand_inlined()) {
+        // Traverse inlined frames.
+        for (InlinedFunctionsIterator it(code, pc); !it.Done(); it.Advance()) {
+          function = it.function();
+          code = it.code();
+          ASSERT(function.raw() == code.function());
+          uword pc = it.pc();
+          ASSERT(pc != 0);
+          ASSERT(code.EntryPoint() <= pc);
+          ASSERT(pc < (code.EntryPoint() + code.Size()));
+
+          function_name = function.QualifiedUserVisibleName();
+          script = function.script();
+          script_uri = script.url();
+          const intptr_t token_pos = code.GetTokenIndexOfPC(pc);
+          intptr_t line = -1;
+          intptr_t column = -1;
+          if (token_pos >= 0) {
+            if (script.HasSource()) {
+              script.GetTokenLocation(token_pos, &line, &column);
+            } else {
+              script.GetTokenLocation(token_pos, &line, NULL);
+            }
+          }
+          result->AddFrame(
+            new ExceptionStackFrame(function_name, script_uri, line, column));
+        }
+      } else {
+        function_name = function.QualifiedUserVisibleName();
+        script = function.script();
+        script_uri = script.url();
+        const intptr_t token_pos = code.GetTokenIndexOfPC(pc);
+        intptr_t line = -1;
+        intptr_t column = -1;
+        if (token_pos >= 0) {
+          if (script.HasSource()) {
+            script.GetTokenLocation(token_pos, &line, &column);
+          } else {
+            script.GetTokenLocation(token_pos, &line, NULL);
+          }
+        }
+        result->AddFrame(
+          new ExceptionStackFrame(function_name, script_uri, line, column));
+      }
+    }
+  }
+
+  return result;
+}
+
+
 void JSRegExp::set_pattern(const String& pattern) const {
   StorePointer(&raw_ptr()->pattern_, pattern.raw());
 }