Add support for javascript incompatibility warnings.

runtime/vm/compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/compiler.h"
 
 #include "vm/assembler.h"
 
 #include "vm/ast_printer.h"
 #include "vm/block_scheduler.h"
@@ skipping 41 matching lines @@
     "Print the IR flow graph when optimizing.");
 DEFINE_FLAG(bool, range_analysis, true, "Enable range analysis");
 DEFINE_FLAG(bool, reorder_basic_blocks, true, "Enable basic-block reordering.");
 DEFINE_FLAG(bool, trace_compiler, false, "Trace compiler operations.");
 DEFINE_FLAG(bool, trace_bailout, false, "Print bailout from ssa compiler.");
 DEFINE_FLAG(bool, use_inlining, true, "Enable call-site inlining");
 DEFINE_FLAG(bool, verify_compiler, false,
     "Enable compiler verification assertions");
 
 DECLARE_FLAG(bool, trace_failed_optimization_attempts);
+DECLARE_FLAG(bool, warn_on_javascript_compatibility);
+DECLARE_FLAG(bool, warning_as_error);
 
 // Compile a function. Should call only if the function has not been compiled.
 //   Arg0: function object.
 DEFINE_RUNTIME_ENTRY(CompileFunction, 1) {
   const Function& function = Function::CheckedHandle(arguments.ArgAt(0));
   ASSERT(!function.HasCode());
   const Error& error = Error::Handle(Compiler::CompileFunction(function));
   if (!error.IsNull()) {
     Exceptions::PropagateError(error);
   }
@@ skipping 517 matching lines @@
           LibraryPrefix& prefix = LibraryPrefix::Handle();
           for (intptr_t i = 0; i < prefixes->Length(); i++) {
             prefix ^= prefixes->At(i);
             prefix.RegisterDependentCode(code);
           }
         }
       }
       is_compiled = true;
       done = true;
     } else {
-      // We bailed out.
+      // We bailed out or we encountered an error.
+      const Error& error = Error::Handle(
+          isolate->object_store()->sticky_error());
 
-      if (isolate->object_store()->sticky_error() ==
-          Object::branch_offset_error().raw()) {
+      if (error.raw() == Object::branch_offset_error().raw()) {
         // Compilation failed due to an out of range branch offset in the
         // assembler. We try again (done = false) with far branches enabled.
         done = false;
         ASSERT(!use_far_branches);
         use_far_branches = true;
       } else {
         // If the error isn't due to an out of range branch offset, we don't
         // try again (done = true), and indicate that we did not finish
         // compiling (is_compiled = false).
         if (FLAG_trace_bailout) {
-          const Error& bailout_error = Error::Handle(
-              isolate->object_store()->sticky_error());
-          OS::Print("%s\n", bailout_error.ToErrorCString());
+          OS::Print("%s\n", error.ToErrorCString());
         }
         done = true;
-        ASSERT(optimized);
+        ASSERT(optimized ||
+               (FLAG_warn_on_javascript_compatibility &&
+                FLAG_warning_as_error));
       }
 
-      isolate->object_store()->clear_sticky_error();
+      // Clear the error if it was not a real error, but just a bailout.
+      if (error.IsLanguageError() &&
+          (LanguageError::Cast(error).kind() == LanguageError::kBailout)) {
+        isolate->object_store()->clear_sticky_error();
+      }
       is_compiled = false;
     }
     // Reset global isolate state.
     isolate->set_deopt_id(prev_deopt_id);
   }
   return is_compiled;
 }
 
 
 static void DisassembleCode(const Function& function, bool optimized) {
@@ skipping 152 matching lines @@
                 (function.end_token_pos() - function.token_pos()));
     }
     {
       HANDLESCOPE(isolate);
       Parser::ParseFunction(parsed_function);
       parsed_function->AllocateVariables();
     }
 
     const bool success =
         CompileParsedFunctionHelper(parsed_function, optimized, osr_id);
-    if (optimized && !success) {
-      // Optimizer bailed out. Disable optimizations and to never try again.
-      if (FLAG_trace_compiler) {
-        OS::Print("--> disabling optimizations for '%s'\n",
-                  function.ToFullyQualifiedCString());
-      } else if (FLAG_trace_failed_optimization_attempts) {
-        OS::Print("Cannot optimize: %s\n", function.ToFullyQualifiedCString());
+    if (!success) {
+      if (optimized) {
+        // Optimizer bailed out. Disable optimizations and to never try again.
+        if (FLAG_trace_compiler) {
+          OS::Print("--> disabling optimizations for '%s'\n",
+                    function.ToFullyQualifiedCString());
+        } else if (FLAG_trace_failed_optimization_attempts) {
+          OS::Print("Cannot optimize: %s\n",
+                    function.ToFullyQualifiedCString());
+        }
+        function.SetIsOptimizable(false);
+        return Error::null();
       }
-      function.SetIsOptimizable(false);
-      return Error::null();
+      // So far, the only possible real error is a JS warning reported as error.
+      ASSERT(FLAG_warn_on_javascript_compatibility && FLAG_warning_as_error);
+      Error& error = Error::Handle();
+      // We got an error during compilation.
+      error = isolate->object_store()->sticky_error();
+      ASSERT(!error.IsNull());
+      isolate->object_store()->clear_sticky_error();
+      return error.raw();
     }
 
-    ASSERT(success);
     per_compile_timer.Stop();
 
     if (FLAG_trace_compiler) {
       OS::Print("--> '%s' entry: %#" Px " size: %" Pd " time: %" Pd64 " us\n",
                 function.ToFullyQualifiedCString(),
                 Code::Handle(function.CurrentCode()).EntryPoint(),
                 Code::Handle(function.CurrentCode()).Size(),
                 per_compile_timer.TotalElapsedTime());
     }
 
@@ skipping 150 matching lines @@
     const Object& result =
       Object::Handle(isolate->object_store()->sticky_error());
     isolate->object_store()->clear_sticky_error();
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 }  // namespace dart