Rewrite HInstruction::Is/As<type>().

Make Is<type>() and As<type>() non-virtual for concrete
instruction types, relying on GetKind(), and mark GetKind()
as PURE to improve optimization opportunities. This reduces
the number of relocations in libart-compiler.so's .rel.dyn
section by ~4K, or ~44%, and in .data.rel.ro by ~18K, or
~65%. The file is 96KiB smaller for Nexus 5, including 8KiB
reduction of the .text section.

Unfortunately, the g++/clang++ __attribute__((pure)) is not
strong enough to avoid duplicated virtual calls and we would
need the C++ [[pure]] attribute proposed in n3744 instead.
To work around this deficiency, we introduce an extra
non-virtual indirection for GetKind(), so that the compiler
can optimize common expressions such as
    instruction->IsAdd() || instruction->IsSub()
or
    instruction->IsAdd() && instruction->AsAdd()->...
which contain two virtual calls to GetKind() after inlining.

Change-Id: I83787de0671a5cb9f5b0a5f4a536cef239d5b401

1 files changed, 5 insertions, 1 deletions

diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 926bc156cf..a37298c76e 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -777,6 +777,10 @@ void HEnvironment::RemoveAsUserOfInput(size_t index) const {
   user_record.GetInstruction()->RemoveEnvironmentUser(user_record.GetUseNode());
 }
 
+HInstruction::InstructionKind HInstruction::GetKind() const {
+  return GetKindInternal();
+}
+
 HInstruction* HInstruction::GetNextDisregardingMoves() const {
   HInstruction* next = GetNext();
   while (next != nullptr && next->IsParallelMove()) {
@@ -960,7 +964,7 @@ void H##name::Accept(HGraphVisitor* visitor) {                                 \
   visitor->Visit##name(this);                                                  \
 }
 
-FOR_EACH_INSTRUCTION(DEFINE_ACCEPT)
+FOR_EACH_CONCRETE_INSTRUCTION(DEFINE_ACCEPT)
 
 #undef DEFINE_ACCEPT