Use iterators "before" the use node in HUserRecord<>.

Create a new template class IntrusiveForwardList<> that
mimicks std::forward_list<> except that all allocations
are handled externally. This is essentially the same as
boost::intrusive::slist<> but since we're not using Boost
we have to reinvent the wheel.

Use the new container to replace the HUseList and use the
iterators to "before" use nodes in HUserRecord<> to avoid
the extra pointer to the previous node which was used
exclusively for removing nodes from the list. This reduces
the size of the HUseListNode by 25%, 32B to 24B in 64-bit
compiler, 16B to 12B in 32-bit compiler. This translates
directly to overall memory savings for the 64-bit compiler
but due to rounding up of the arena allocations to 8B, we
do not get any improvement in the 32-bit compiler.

Compiling the Nexus 5 boot image with the 64-bit dex2oat
on host this CL reduces the memory used for compiling the
most hungry method, BatteryStats.dumpLocked(), by ~3.3MiB:

Before:
  MEM: used: 47829200, allocated: 48769120, lost: 939920
  Number of arenas allocated: 345,
  Number of allocations: 815492, avg size: 58
  ...
  UseListNode    13744640
  ...
After:
  MEM: used: 44393040, allocated: 45361248, lost: 968208
  Number of arenas allocated: 319,
  Number of allocations: 815492, avg size: 54
  ...
  UseListNode    10308480
  ...

Note that while we do not ship the 64-bit dex2oat to the
device, the JIT compilation for 64-bit processes is using
the 64-bit libart-compiler.

Bug: 28173563
Change-Id: I985eabd4816f845372d8aaa825a1489cf9569208

1 files changed, 4 insertions, 4 deletions

diff --git a/compiler/optimizing/nodes_test.cc b/compiler/optimizing/nodes_test.cc
index 764f5fec5b..d4e2a58103 100644
--- a/compiler/optimizing/nodes_test.cc
+++ b/compiler/optimizing/nodes_test.cc
@@ -91,7 +91,7 @@ TEST(Node, InsertInstruction) {
   entry->InsertInstructionBefore(to_insert, parameter2);
 
   ASSERT_TRUE(parameter1->HasUses());
-  ASSERT_TRUE(parameter1->GetUses().HasOnlyOneUse());
+  ASSERT_TRUE(parameter1->GetUses().HasExactlyOneElement());
 }
 
 /**
@@ -115,7 +115,7 @@ TEST(Node, AddInstruction) {
   entry->AddInstruction(to_add);
 
   ASSERT_TRUE(parameter->HasUses());
-  ASSERT_TRUE(parameter->GetUses().HasOnlyOneUse());
+  ASSERT_TRUE(parameter->GetUses().HasExactlyOneElement());
 }
 
 TEST(Node, ParentEnvironment) {
@@ -134,7 +134,7 @@ TEST(Node, ParentEnvironment) {
   entry->AddInstruction(new (&allocator) HExit());
 
   ASSERT_TRUE(parameter1->HasUses());
-  ASSERT_TRUE(parameter1->GetUses().HasOnlyOneUse());
+  ASSERT_TRUE(parameter1->GetUses().HasExactlyOneElement());
 
   HEnvironment* environment = new (&allocator) HEnvironment(
       &allocator, 1, graph->GetDexFile(), graph->GetMethodIdx(), 0, kStatic, with_environment);
@@ -145,7 +145,7 @@ TEST(Node, ParentEnvironment) {
   with_environment->SetRawEnvironment(environment);
 
   ASSERT_TRUE(parameter1->HasEnvironmentUses());
-  ASSERT_TRUE(parameter1->GetEnvUses().HasOnlyOneUse());
+  ASSERT_TRUE(parameter1->GetEnvUses().HasExactlyOneElement());
 
   HEnvironment* parent1 = new (&allocator) HEnvironment(
       &allocator, 1, graph->GetDexFile(), graph->GetMethodIdx(), 0, kStatic, nullptr);