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, 2 insertions, 0 deletions

diff --git a/compiler/optimizing/code_generator_arm.h b/compiler/optimizing/code_generator_arm.h
index 8193c2808c..b7c58e1248 100644
--- a/compiler/optimizing/code_generator_arm.h
+++ b/compiler/optimizing/code_generator_arm.h
@@ -170,6 +170,7 @@ class LocationsBuilderARM : public HGraphVisitor {
  private:
   void HandleInvoke(HInvoke* invoke);
   void HandleBitwiseOperation(HBinaryOperation* operation, Opcode opcode);
+  void HandleCondition(HCondition* condition);
   void HandleIntegerRotate(LocationSummary* locations);
   void HandleLongRotate(LocationSummary* locations);
   void HandleRotate(HRor* ror);
@@ -216,6 +217,7 @@ class InstructionCodeGeneratorARM : public HGraphVisitor {
   void GenerateOrrConst(Register out, Register first, uint32_t value);
   void GenerateEorConst(Register out, Register first, uint32_t value);
   void HandleBitwiseOperation(HBinaryOperation* operation);
+  void HandleCondition(HCondition* condition);
   void HandleIntegerRotate(LocationSummary* locations);
   void HandleLongRotate(LocationSummary* locations);
   void HandleRotate(HRor* ror);