Relax inlining limits for simple leaf functions.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 39a68cc6e1e946b1b006c1ef2caa4d5dbcc390a9..284c53629e23a50ba2e8f5f5102f98dd251e4a4c 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -4646,11 +4646,37 @@ bool HGraphBuilder::TryInline(Call* expr, bool drop_extra) {
   Handle<JSFunction> target = expr->target();
   Handle<SharedFunctionInfo> target_shared(target->shared());
 
-  // Do a quick check on source code length to avoid parsing large
-  // inlining candidates.
-  if (FLAG_limit_inlining && target->shared()->SourceSize() > kMaxSourceSize) {
-    TraceInline(target, caller, "target text too big");
-    return false;
+  int ast_node_count = target_shared->ast_node_count();
+
+  if (FLAG_limit_inlining) {
+    if (ast_node_count > kMaxInlinedSize) {
+      // Never inline big functions.
+      TraceInline(target, caller, "target AST is too large");
+      return false;
+    }
+
+    if (target->shared()->SourceSize() > kMaxSourceSize) {
+      // Never inline big functions.
+      TraceInline(target, caller, "target text too big");
+      return false;
+    }
+
+    if (inlined_count_ > kMaxInlinedNodesHard) {
+      // Do not inline after the hard limit is reached.
+      TraceInline(target, caller, "cumulative AST node limit reached");
+      return false;
+    }
+
+    if (inlined_count_ > kMaxInlinedNodesSoft) {
+      // Inline only small "primitive" functions after reaching the soft limit,
+      // where "primitive" is defined by syntactic criterion.
+      if (ast_node_count > kMaxInlinedPrimitiveSize ||
+          inlined_count_ > kMaxInlinedNodesHard ||

[Kevin Millikin (Chromium), 2011/11/28 12:11:59]

I think 'inlined_count_ > MaxInlinedNodesHard' is trivially false, because
you've already bailed out otherwise.

[ulan, 2011/11/29 14:06:52]

Done.

+          !target_shared->is_primitive()) {
+        TraceInline(target, caller, "cumulative AST node limit reached");

[Kevin Millikin (Chromium), 2011/11/28 12:11:59]

This should be a distinct bailout message from the earlier one, so it's easy to
see which limit is in play from inspecting --trace-bailout.

[ulan, 2011/11/29 14:06:52]

Done.

+        return false;
+      }
+    }
   }
 
   // Target must be inlineable.
@@ -4693,14 +4719,6 @@ bool HGraphBuilder::TryInline(Call* expr, bool drop_extra) {
     }
   }
 
-  // We don't want to add more than a certain number of nodes from inlining.
-  if (FLAG_limit_inlining && inlined_count_ > kMaxInlinedNodes) {
-    TraceInline(target, caller, "cumulative AST node limit reached");
-    return false;
-  }
-
-  int count_before = AstNode::Count();
-
   // Parse and allocate variables.
   CompilationInfo target_info(target);
   if (!ParserApi::Parse(&target_info) ||
@@ -4720,13 +4738,6 @@ bool HGraphBuilder::TryInline(Call* expr, bool drop_extra) {
   }
   FunctionLiteral* function = target_info.function();
 
-  // Count the number of AST nodes added by inlining this call.
-  int nodes_added = AstNode::Count() - count_before;
-  if (FLAG_limit_inlining && nodes_added > kMaxInlinedSize) {
-    TraceInline(target, caller, "target AST is too large");
-    return false;
-  }
-
   // Don't inline functions that uses the arguments object or that
   // have a mismatching number of parameters.
   int arity = expr->arguments()->length();
@@ -4829,7 +4840,7 @@ bool HGraphBuilder::TryInline(Call* expr, bool drop_extra) {
   }
 
   // Update inlined nodes count.
-  inlined_count_ += nodes_added;
+  inlined_count_ += ast_node_count;
 
   TraceInline(target, caller, NULL);