[turbofan] basic block profiler

src/compiler/basic-block-instrumentor.cc

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/compiler/basic-block-instrumentor.h"
+#include "src/compiler/common-operator.h"
+#include "src/compiler/graph.h"
+#include "src/compiler/machine-operator.h"
+#include "src/compiler/operator-properties-inl.h"
+#include "src/compiler/schedule.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// Find the first place to insert new nodes in a block that's already been
+// scheduled that won't upset the register allocator.
+static NodeVector::iterator FindInsertionPoint(NodeVector* nodes) {
+  NodeVector::iterator i = nodes->begin();
+  for (; i != nodes->end(); ++i) {
+    const Operator* op = (*i)->op();
+    if (OperatorProperties::IsBasicBlockBegin(op)) continue;
+    switch (op->opcode()) {
+      case IrOpcode::kParameter:
+      case IrOpcode::kPhi:
+      case IrOpcode::kEffectPhi:
+        continue;
+    }
+    break;
+  }
+  return i;
+}
+
+
+// TODO(dcarney): need to mark code as non-serializable.
+static const Operator* PointerConstant(CommonOperatorBuilder* common,
+                                       void* ptr) {
+  return kPointerSize == 8
+             ? common->Int64Constant(reinterpret_cast<intptr_t>(ptr))
+             : common->Int32Constant(
+                   static_cast<int32_t>(reinterpret_cast<intptr_t>(ptr)));
+}
+
+
+BasicBlockProfiler::Data* BasicBlockInstrumentor::Instrument(
+    CompilationInfo* info, Graph* graph, Schedule* schedule) {
+  // Skip the exit block in profiles, since the register allocator can't handle
+  // it and entry into it means falling off the end of the function anyway.
+  size_t n_blocks = static_cast<size_t>(schedule->RpoBlockCount()) - 1;
+  BasicBlockProfiler::Data* data =
+      info->isolate()->GetOrCreateBasicBlockProfiler()->NewData(n_blocks);
+  // Set the function name.
+  if (!info->shared_info().is_null() &&
+      info->shared_info()->name()->IsString()) {
+    OStringStream os;
+    String::cast(info->shared_info()->name())->PrintUC16(os);
+    data->SetFunctionName(&os);
+  }
+  // Capture the schedule string before instrumentation.
+  {
+    OStringStream os;
+    os << *schedule;
+    data->SetSchedule(&os);
+  }
+  // Add the increment instructions to the start of every block.
+  CommonOperatorBuilder common(graph->zone());
+  Node* zero = graph->NewNode(common.Int32Constant(0));
+  Node* one = graph->NewNode(common.Int32Constant(1));
+  MachineOperatorBuilder machine;
+  BasicBlockVector* blocks = schedule->rpo_order();
+  size_t block_number = 0;
+  for (BasicBlockVector::iterator it = blocks->begin(); block_number < n_blocks;
+       ++it, ++block_number) {
+    BasicBlock* block = (*it);
+    data->SetBlockId(block_number, block->id());
+    // TODO(dcarney): wire effect and control deps for load and store.
+    // Construct increment operation.
+    Node* base = graph->NewNode(
+        PointerConstant(&common, data->GetCounterAddress(block_number)));
+    Node* load = graph->NewNode(machine.Load(kMachUint32), base, zero);
+    Node* inc = graph->NewNode(machine.Int32Add(), load, one);
+    Node* store = graph->NewNode(
+        machine.Store(StoreRepresentation(kMachUint32, kNoWriteBarrier)), base,
+        zero, inc);
+    // Insert the new nodes.
+    static const int kArraySize = 6;
+    Node* to_insert[kArraySize] = {zero, one, base, load, inc, store};

[titzer, 2014/09/25 09:13:59]

I don't think you want to insert zero and one in every block; every node should
have just one place in the schedule.

[dcarney, 2014/09/25 09:17:11]

zero and one ARE in only one spot, see next line

+    int insertion_start = block_number == 0 ? 0 : 2;
+    NodeVector* nodes = &block->nodes_;
+    NodeVector::iterator insertion_point = FindInsertionPoint(nodes);
+    nodes->insert(insertion_point, &to_insert[insertion_start],
+                  &to_insert[kArraySize]);
+    // Tell the scheduler about the new nodes.
+    for (int i = insertion_start; i < kArraySize; ++i) {
+      schedule->SetBlockForNode(block, to_insert[i]);
+    }
+  }
+  return data;
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8