ART: Clean up arm64 kNumberOfXRegisters usage.

Avoid undefined behavior for arm64 stemming from 1u << 32 in
loops with upper bound kNumberOfXRegisters.

Create iterators for enumerating bits in an integer either
from high to low or from low to high and use them for
<arch>Context::FillCalleeSaves() on all architectures.

Refactor runtime/utils.{h,cc} by moving all bit-fiddling
functions to runtime/base/bit_utils.{h,cc} (together with
the new bit iterators) and all time-related functions to
runtime/base/time_utils.{h,cc}. Improve test coverage and
fix some corner cases for the bit-fiddling functions.

Bug: 13925192
Change-Id: I704884dab15b41ecf7a1c47d397ab1c3fc7ee0f7

6 files changed, 6 insertions, 7 deletions

diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 1c76630efe..5f8023de2a 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -494,11 +494,6 @@ InstructionCodeGeneratorARM::InstructionCodeGeneratorARM(HGraph* graph, CodeGene
         assembler_(codegen->GetAssembler()),
         codegen_(codegen) {}
 
-static uint32_t LeastSignificantBit(uint32_t mask) {
-  // ffs starts at 1.
-  return ffs(mask) - 1;
-}
-
 void CodeGeneratorARM::ComputeSpillMask() {
   core_spill_mask_ = allocated_registers_.GetCoreRegisters() & core_callee_save_mask_;
   // Save one extra register for baseline. Note that on thumb2, there is no easy
@@ -2222,7 +2217,7 @@ void InstructionCodeGeneratorARM::DivRemByPowerOfTwo(HBinaryOperation* instructi
   Register dividend = locations->InAt(0).AsRegister<Register>();
   Register temp = locations->GetTemp(0).AsRegister<Register>();
   int32_t imm = second.GetConstant()->AsIntConstant()->GetValue();
-  int32_t abs_imm = std::abs(imm);
+  uint32_t abs_imm = static_cast<uint32_t>(std::abs(imm));
   DCHECK(IsPowerOfTwo(abs_imm));
   int ctz_imm = CTZ(abs_imm);
 
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index b6d99abca0..ced60cd33f 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -1738,7 +1738,7 @@ void InstructionCodeGeneratorARM64::DivRemByPowerOfTwo(HBinaryOperation* instruc
   Register out = OutputRegister(instruction);
   Register dividend = InputRegisterAt(instruction, 0);
   int64_t imm = Int64FromConstant(second.GetConstant());
-  int64_t abs_imm = std::abs(imm);
+  uint64_t abs_imm = static_cast<uint64_t>(std::abs(imm));
   DCHECK(IsPowerOfTwo(abs_imm));
   int ctz_imm = CTZ(abs_imm);
 
diff --git a/compiler/optimizing/intrinsics.cc b/compiler/optimizing/intrinsics.cc
index 43fe3746ad..9e18f114ad 100644
--- a/compiler/optimizing/intrinsics.cc
+++ b/compiler/optimizing/intrinsics.cc
@@ -22,6 +22,7 @@
 #include "invoke_type.h"
 #include "nodes.h"
 #include "quick/inline_method_analyser.h"
+#include "utils.h"
 
 namespace art {
 
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 47da9cc17c..91daeb7a4c 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -19,6 +19,7 @@
 #include "code_generator.h"
 #include "ssa_builder.h"
 #include "base/bit_vector-inl.h"
+#include "base/bit_utils.h"
 #include "utils/growable_array.h"
 #include "scoped_thread_state_change.h"
 
diff --git a/compiler/optimizing/parallel_move_resolver.h b/compiler/optimizing/parallel_move_resolver.h
index e89417df7d..9ede91013e 100644
--- a/compiler/optimizing/parallel_move_resolver.h
+++ b/compiler/optimizing/parallel_move_resolver.h
@@ -20,6 +20,7 @@
 #include "base/value_object.h"
 #include "utils/growable_array.h"
 #include "locations.h"
+#include "primitive.h"
 
 namespace art {
 
diff --git a/compiler/optimizing/register_allocator.h b/compiler/optimizing/register_allocator.h
index 6d5bfc3f0d..c29fe75921 100644
--- a/compiler/optimizing/register_allocator.h
+++ b/compiler/optimizing/register_allocator.h
@@ -17,6 +17,7 @@
 #ifndef ART_COMPILER_OPTIMIZING_REGISTER_ALLOCATOR_H_
 #define ART_COMPILER_OPTIMIZING_REGISTER_ALLOCATOR_H_
 
+#include "arch/instruction_set.h"
 #include "base/macros.h"
 #include "primitive.h"
 #include "utils/growable_array.h"