VM: Speculative inlining in precompiled code.

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 45 matching lines @@
     "Print the IR flow graph when optimizing.");
 DEFINE_FLAG(bool, print_ic_data_map, false,
     "Print the deopt-id to ICData map in optimizing compiler.");
 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");
+DEFINE_FLAG(int, max_speculative_inlining_attempts, 1,
+    "Max number of attempts with speculative inlining (precompilation only)");
 
 DECLARE_FLAG(bool, background_compilation);
 DECLARE_FLAG(bool, load_deferred_eagerly);
 DECLARE_FLAG(bool, trace_failed_optimization_attempts);
 DECLARE_FLAG(bool, trace_inlining_intervals);
 DECLARE_FLAG(bool, trace_irregexp);
 
 
 bool Compiler::always_optimize_ = false;
 bool Compiler::allow_recompilation_ = true;
@@ skipping 329 matching lines @@
 
   // We may reattempt compilation if the function needs to be assembled using
   // far branches on ARM and MIPS. In the else branch of the setjmp call,
   // done is set to false, and use_far_branches is set to true if there is a
   // longjmp from the ARM or MIPS assemblers. In all other paths through this
   // while loop, done is set to true. use_far_branches is always false on ia32
   // and x64.
   bool done = false;
   // volatile because the variable may be clobbered by a longjmp.
   volatile bool use_far_branches = false;
+  volatile bool use_speculative_inlining = true;
+  GrowableArray<intptr_t> inlining_black_list;
+
   while (!done) {
     const intptr_t prev_deopt_id = thread->deopt_id();
     thread->set_deopt_id(0);
     LongJumpScope jump;
-    if (setjmp(*jump.Set()) == 0) {
+    const intptr_t val = setjmp(*jump.Set());
+    if (val == 0) {
       FlowGraph* flow_graph = NULL;
 
       // Class hierarchy analysis is registered with the isolate in the
       // constructor and unregisters itself upon destruction.
       CHA cha(thread);
 
       // TimerScope needs an isolate to be properly terminated in case of a
       // LongJump.
       {
         CSTAT_TIMER_SCOPE(thread, graphbuilder_timer);
@@ skipping 63 matching lines @@
       GrowableArray<intptr_t> caller_inline_id;
       // Collect all instance fields that are loaded in the graph and
       // have non-generic type feedback attached to them that can
       // potentially affect optimizations.
       if (optimized) {
         inline_id_to_function.Add(&function);
         // Top scope function has no caller (-1).
         caller_inline_id.Add(-1);
         CSTAT_TIMER_SCOPE(thread, graphoptimizer_timer);
 
-        FlowGraphOptimizer optimizer(flow_graph);
+        FlowGraphOptimizer optimizer(flow_graph,
+                                     use_speculative_inlining,
+                                     &inlining_black_list);
         if (Compiler::always_optimize()) {
           optimizer.PopulateWithICData();
+
+          optimizer.ApplyClassIds();
+          DEBUG_ASSERT(flow_graph->VerifyUseLists());
+
+          FlowGraphTypePropagator::Propagate(flow_graph);
+          DEBUG_ASSERT(flow_graph->VerifyUseLists());
         }
         optimizer.ApplyICData();
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         // Optimize (a << b) & c patterns, merge operations.
         // Run early in order to have more opportunity to optimize left shifts.
         optimizer.TryOptimizePatterns();
         DEBUG_ASSERT(flow_graph->VerifyUseLists());
 
         FlowGraphInliner::SetInliningId(flow_graph, 0);
@@ skipping 347 matching lines @@
       // We bailed out or we encountered an error.
       const Error& error = Error::Handle(
           isolate->object_store()->sticky_error());
 
       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 (error.raw() == Object::speculative_inlining_error().raw()) {
+        // The return value of setjmp is the deopt id of the check instruction
+        // that caused the bailout.
+        done = false;
+#if defined(DEBUG)
+        ASSERT(Compiler::always_optimize());
+        ASSERT(use_speculative_inlining);
+        for (intptr_t i = 0; i < inlining_black_list.length(); ++i) {
+          ASSERT(inlining_black_list[i] != val);
+        }
+#endif
+        inlining_black_list.Add(val);
+        const intptr_t max_attempts = FLAG_max_speculative_inlining_attempts;
+        if (inlining_black_list.length() >= max_attempts) {
+          use_speculative_inlining = false;
+          if (FLAG_trace_compiler) {
+            THR_Print("Disabled speculative inlining after %" Pd " attempts.\n",
+                      inlining_black_list.length());
+          }
+        }
       } 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) {
           THR_Print("%s\n", error.ToErrorCString());
         }
         done = true;
       }
 
@@ skipping 1082 matching lines @@
       isolate->set_background_compiler(task);
       start_task = true;
     }
   }
   if (start_task) {
     Dart::thread_pool()->Run(isolate->background_compiler());
   }
 }
 
 }  // namespace dart