From fb1795c4429eecc3af14f51417664aeba15fb0de Mon Sep 17 00:00:00 2001
From: Dan Carney <dcarney@chromium.org>
Date: Fri, 14 Nov 2014 09:56:56 +0100
Subject: [PATCH] [turbofan] small cleanups to aid register allocator debugging

BUG=
R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/727693002

Cr-Commit-Position: refs/heads/master@{#25350}
---
 src/compiler/pipeline.cc           | 11 +++-----
 src/compiler/register-allocator.cc | 52 +++++++++++++++++++++-----------------
 src/compiler/register-allocator.h  |  1 +
 3 files changed, 34 insertions(+), 30 deletions(-)

diff --git a/src/compiler/pipeline.cc b/src/compiler/pipeline.cc
index 53a0afc..e4d8c5d 100644
--- a/src/compiler/pipeline.cc
+++ b/src/compiler/pipeline.cc
@@ -110,6 +110,8 @@ class PipelineData {
   }
 
   Zone* instruction_zone() const { return instruction_zone_; }
+  // RawMachineAssembler generally produces graphs which cannot be verified.
+  bool MayHaveUnverifiableGraph() const { return outer_zone_ == nullptr; }
 
   void DeleteGraphZone() {
     // Destroy objects with destructors first.
@@ -563,12 +565,7 @@ Handle<Code> Pipeline::GenerateCode(Linkage* linkage, PipelineData* data) {
     selector.SelectInstructions();
   }
 
-  if (FLAG_trace_turbo) {
-    OFStream os(stdout);
-    PrintableInstructionSequence printable = {
-        RegisterConfiguration::ArchDefault(), &sequence};
-    os << "----- Instruction sequence before register allocation -----\n"
-       << printable;
+  if (FLAG_trace_turbo && !data->MayHaveUnverifiableGraph()) {
     TurboCfgFile tcf(isolate());
     tcf << AsC1V("CodeGen", data->schedule(), data->source_positions(),
                  &sequence);
@@ -609,7 +606,7 @@ Handle<Code> Pipeline::GenerateCode(Linkage* linkage, PipelineData* data) {
       info()->AbortOptimization(kNotEnoughVirtualRegistersRegalloc);
       return Handle<Code>::null();
     }
-    if (FLAG_trace_turbo) {
+    if (FLAG_trace_turbo && !data->MayHaveUnverifiableGraph()) {
       TurboCfgFile tcf(isolate());
       tcf << AsC1VAllocator("CodeGen", &allocator);
     }
diff --git a/src/compiler/register-allocator.cc b/src/compiler/register-allocator.cc
index 23a7df6..c314509 100644
--- a/src/compiler/register-allocator.cc
+++ b/src/compiler/register-allocator.cc
@@ -1125,7 +1125,6 @@ bool RegisterAllocator::Allocate(PipelineStatistics* stats) {
     PhaseScope phase_scope(stats, "meet register constraints");
     MeetRegisterConstraints();
   }
-  if (!AllocationOk()) return false;
   {
     PhaseScope phase_scope(stats, "resolve phis");
     ResolvePhis();
@@ -1134,6 +1133,14 @@ bool RegisterAllocator::Allocate(PipelineStatistics* stats) {
     PhaseScope phase_scope(stats, "build live ranges");
     BuildLiveRanges();
   }
+  if (FLAG_trace_turbo) {
+    OFStream os(stdout);
+    PrintableInstructionSequence printable = {config(), code()};
+    os << "----- Instruction sequence before register allocation -----\n"
+       << printable;
+  }
+  // This can be triggered in debug mode.
+  DCHECK(!ExistsUseWithoutDefinition());
   {
     PhaseScope phase_scope(stats, "allocate general registers");
     AllocateGeneralRegisters();
@@ -1487,28 +1494,6 @@ void RegisterAllocator::BuildLiveRanges() {
         live_in_sets_[i]->Union(*live);
       }
     }
-
-#ifdef DEBUG
-    if (block_id == 0) {
-      BitVector::Iterator iterator(live);
-      bool found = false;
-      while (!iterator.Done()) {
-        found = true;
-        int operand_index = iterator.Current();
-        PrintF("Register allocator error: live v%d reached first block.\n",
-               operand_index);
-        LiveRange* range = LiveRangeFor(operand_index);
-        PrintF("  (first use is at %d)\n", range->first_pos()->pos().Value());
-        if (debug_name() == nullptr) {
-          PrintF("\n");
-        } else {
-          PrintF("  (function: %s)\n", debug_name());
-        }
-        iterator.Advance();
-      }
-      DCHECK(!found);
-    }
-#endif
   }
 
   for (int i = 0; i < live_ranges_.length(); ++i) {
@@ -1539,6 +1524,27 @@ void RegisterAllocator::BuildLiveRanges() {
 }
 
 
+bool RegisterAllocator::ExistsUseWithoutDefinition() {
+  bool found = false;
+  BitVector::Iterator iterator(live_in_sets_[0]);
+  while (!iterator.Done()) {
+    found = true;
+    int operand_index = iterator.Current();
+    PrintF("Register allocator error: live v%d reached first block.\n",
+           operand_index);
+    LiveRange* range = LiveRangeFor(operand_index);
+    PrintF("  (first use is at %d)\n", range->first_pos()->pos().Value());
+    if (debug_name() == nullptr) {
+      PrintF("\n");
+    } else {
+      PrintF("  (function: %s)\n", debug_name());
+    }
+    iterator.Advance();
+  }
+  return found;
+}
+
+
 bool RegisterAllocator::SafePointsAreInOrder() const {
   int safe_point = 0;
   const PointerMapDeque* pointer_maps = code()->pointer_maps();
diff --git a/src/compiler/register-allocator.h b/src/compiler/register-allocator.h
index a6578af..067ed87 100644
--- a/src/compiler/register-allocator.h
+++ b/src/compiler/register-allocator.h
@@ -388,6 +388,7 @@ class RegisterAllocator FINAL {
   bool IsOutputRegisterOf(Instruction* instr, int index);
   bool IsOutputDoubleRegisterOf(Instruction* instr, int index);
   void ProcessInstructions(const InstructionBlock* block, BitVector* live);
+  bool ExistsUseWithoutDefinition();
   void MeetRegisterConstraints(const InstructionBlock* block);
   void MeetConstraintsBetween(Instruction* first, Instruction* second,
                               int gap_index);
-- 
2.7.4