Replaced a bailout ID assertion with quadratic time complexity by a linear one.

This reduces the time to run our test suite in debug mode considerably (from
8:43 to 4:05 on my local workstation using 32 threads). Note that the assertion
is so fast now that it doesn't need to be hidden behind --enable-slow-asserts.
Furthermore, the bookkeeping of the set is not measurable in all our benchmarks,
so I intentionally avoided any #ifdef chaos to keep things simple.

Review URL: https://codereview.chromium.org/11745027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13312 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/data-flow.h

@@ -199,6 +199,40 @@ class BitVector: public ZoneObject {
   uint32_t* data_;
 };
 
+class GrowableBitVector BASE_EMBEDDED {
+ public:
+  GrowableBitVector() : bits_(NULL) { }
+
+  bool Contains(int value) const {
+    if (!InBitsRange(value)) return false;
+    return bits_->Contains(value);
+  }
+
+  void Add(int value, Zone* zone) {
+    EnsureCapacity(value, zone);
+    bits_->Add(value);
+  }
+
+ private:
+  static const int kInitialLength = 1024;
+
+  bool InBitsRange(int value) const {
+    return bits_ != NULL && bits_->length() > value;
+  }
+
+  void EnsureCapacity(int value, Zone* zone) {
+    if (InBitsRange(value)) return;
+    int new_length = bits_ == NULL ? kInitialLength : bits_->length();
+    while (new_length <= value) new_length *= 2;
+    BitVector* new_bits = new(zone) BitVector(new_length, zone);
+    if (bits_ != NULL) new_bits->CopyFrom(*bits_);
+    bits_ = new_bits;
+  }
+
+  BitVector* bits_;
+};
+
+
 } }  // namespace v8::internal
 
 

src/full-codegen.cc

@@ -448,18 +448,8 @@ void FullCodeGenerator::PrepareForBailoutForId(BailoutId id, State state) {
       StateField::encode(state) | PcField::encode(masm_->pc_offset());
   ASSERT(Smi::IsValid(pc_and_state));
   BailoutEntry entry = { id, pc_and_state };
-#ifdef DEBUG
-  if (FLAG_enable_slow_asserts) {
-    // Assert that we don't have multiple bailout entries for the same node.
-    for (int i = 0; i < bailout_entries_.length(); i++) {
-      if (bailout_entries_.at(i).id == entry.id) {
-        AstPrinter printer;
-        PrintF("%s", printer.PrintProgram(info_->function()));
-        UNREACHABLE();
-      }
-    }
-  }
-#endif  // DEBUG
+  ASSERT(!prepared_bailout_ids_.Contains(id.ToInt()));
+  prepared_bailout_ids_.Add(id.ToInt(), zone());
   bailout_entries_.Add(entry, zone());
 }
 

src/full-codegen.h

@@ -35,6 +35,7 @@
 #include "code-stubs.h"
 #include "codegen.h"
 #include "compiler.h"
+#include "data-flow.h"
 
 namespace v8 {
 namespace internal {
@@ -816,6 +817,7 @@ class FullCodeGenerator: public AstVisitor {
   int module_index_;
   const ExpressionContext* context_;
   ZoneList<BailoutEntry> bailout_entries_;
+  GrowableBitVector prepared_bailout_ids_;
   // TODO(svenpanne) Rename this to something like back_edges_ and rename
   // related functions accordingly.
   ZoneList<BailoutEntry> stack_checks_;

src/lithium-allocator.h

@@ -399,40 +399,6 @@ class LiveRange: public ZoneObject {
 };
 
 
-class GrowableBitVector BASE_EMBEDDED {
- public:
-  GrowableBitVector() : bits_(NULL) { }
-
-  bool Contains(int value) const {
-    if (!InBitsRange(value)) return false;
-    return bits_->Contains(value);
-  }
-
-  void Add(int value, Zone* zone) {
-    EnsureCapacity(value, zone);
-    bits_->Add(value);
-  }
-
- private:
-  static const int kInitialLength = 1024;
-
-  bool InBitsRange(int value) const {
-    return bits_ != NULL && bits_->length() > value;
-  }
-
-  void EnsureCapacity(int value, Zone* zone) {
-    if (InBitsRange(value)) return;
-    int new_length = bits_ == NULL ? kInitialLength : bits_->length();
-    while (new_length <= value) new_length *= 2;
-    BitVector* new_bits = new(zone) BitVector(new_length, zone);
-    if (bits_ != NULL) new_bits->CopyFrom(*bits_);
-    bits_ = new_bits;
-  }
-
-  BitVector* bits_;
-};
-
-
 class LAllocator BASE_EMBEDDED {
  public:
   LAllocator(int first_virtual_register, HGraph* graph);