Merge "Revert "Revert "ARM: VIXL32: Use DontCare for SetFlags + fix for GenerateFrameEntry."""

4 files changed, 115 insertions, 8 deletions

diff --git a/compiler/optimizing/code_generator_arm_vixl.cc b/compiler/optimizing/code_generator_arm_vixl.cc
index c8bdd0163d..3a3d2a9db1 100644
--- a/compiler/optimizing/code_generator_arm_vixl.cc
+++ b/compiler/optimizing/code_generator_arm_vixl.cc
@@ -1400,10 +1400,25 @@ void CodeGeneratorARMVIXL::GenerateFrameEntry() {
     GetAssembler()->cfi().AdjustCFAOffset(kArmWordSize * POPCOUNT(fpu_spill_mask_));
     GetAssembler()->cfi().RelOffsetForMany(DWARFReg(s0), 0, fpu_spill_mask_, kArmWordSize);
   }
+
+  if (GetGraph()->HasShouldDeoptimizeFlag()) {
+    UseScratchRegisterScope temps(GetVIXLAssembler());
+    vixl32::Register temp = temps.Acquire();
+    // Initialize should_deoptimize flag to 0.
+    __ Mov(temp, 0);
+    GetAssembler()->StoreToOffset(kStoreWord, temp, sp, -kShouldDeoptimizeFlagSize);
+  }
+
   int adjust = GetFrameSize() - FrameEntrySpillSize();
   __ Sub(sp, sp, adjust);
   GetAssembler()->cfi().AdjustCFAOffset(adjust);
-  GetAssembler()->StoreToOffset(kStoreWord, kMethodRegister, sp, 0);
+
+  // Save the current method if we need it. Note that we do not
+  // do this in HCurrentMethod, as the instruction might have been removed
+  // in the SSA graph.
+  if (RequiresCurrentMethod()) {
+    GetAssembler()->StoreToOffset(kStoreWord, kMethodRegister, sp, 0);
+  }
 }
 
 void CodeGeneratorARMVIXL::GenerateFrameExit() {
@@ -3606,8 +3621,7 @@ void InstructionCodeGeneratorARMVIXL::HandleLongRotate(HRor* ror) {
 
     __ And(shift_right, RegisterFrom(rhs), 0x1F);
     __ Lsrs(shift_left, RegisterFrom(rhs), 6);
-    // TODO(VIXL): Check that flags are kept after "vixl32::LeaveFlags" enabled.
-    __ Rsb(shift_left, shift_right, Operand::From(kArmBitsPerWord));
+    __ Rsb(LeaveFlags, shift_left, shift_right, Operand::From(kArmBitsPerWord));
     __ B(cc, &shift_by_32_plus_shift_right);
 
     // out_reg_hi = (reg_hi << shift_left) | (reg_lo >> shift_right).
@@ -6758,9 +6772,9 @@ void InstructionCodeGeneratorARMVIXL::GenerateAddLongConst(Location out,
     return;
   }
   __ Adds(out_low, first_low, value_low);
-  if (GetAssembler()->ShifterOperandCanHold(ADC, value_high, kCcKeep)) {
+  if (GetAssembler()->ShifterOperandCanHold(ADC, value_high, kCcDontCare)) {
     __ Adc(out_high, first_high, value_high);
-  } else if (GetAssembler()->ShifterOperandCanHold(SBC, ~value_high, kCcKeep)) {
+  } else if (GetAssembler()->ShifterOperandCanHold(SBC, ~value_high, kCcDontCare)) {
     __ Sbc(out_high, first_high, ~value_high);
   } else {
     LOG(FATAL) << "Unexpected constant " << value_high;
diff --git a/compiler/utils/arm/assembler_arm_vixl.cc b/compiler/utils/arm/assembler_arm_vixl.cc
index c35c39328c..1614d04a95 100644
--- a/compiler/utils/arm/assembler_arm_vixl.cc
+++ b/compiler/utils/arm/assembler_arm_vixl.cc
@@ -455,5 +455,27 @@ void ArmVIXLMacroAssembler::CompareAndBranchIfNonZero(vixl32::Register rn,
   B(ne, label);
 }
 
+void ArmVIXLMacroAssembler::B(vixl32::Label* label) {
+  if (!label->IsBound()) {
+    // Try to use 16-bit T2 encoding of B instruction.
+    DCHECK(OutsideITBlock());
+    AssemblerAccurateScope ass(this,
+                               kMaxInstructionSizeInBytes,
+                               CodeBufferCheckScope::kMaximumSize);
+    b(al, Narrow, label);
+    AddBranchLabel(label);
+    return;
+  }
+  MacroAssembler::B(label);
+}
+
+void ArmVIXLMacroAssembler::B(vixl32::Condition cond, vixl32::Label* label) {
+  // To further reduce the Bcc encoding size and use 16-bit T1 encoding,
+  // we can provide a hint to this function: i.e. far_target=false.
+  // By default this function uses 'EncodingSizeType::Best' which generates 32-bit T3 encoding.
+  MacroAssembler::B(cond, label);
+}
+
+
 }  // namespace arm
 }  // namespace art
diff --git a/compiler/utils/arm/assembler_arm_vixl.h b/compiler/utils/arm/assembler_arm_vixl.h
index b4a4abc87e..17cf1064b0 100644
--- a/compiler/utils/arm/assembler_arm_vixl.h
+++ b/compiler/utils/arm/assembler_arm_vixl.h
@@ -54,6 +54,77 @@ class ArmVIXLMacroAssembler FINAL : public vixl32::MacroAssembler {
   void CompareAndBranchIfNonZero(vixl32::Register rn,
                                  vixl32::Label* label,
                                  bool is_far_target = true);
+
+  // In T32 some of the instructions (add, mov, etc) outside an IT block
+  // have only 32-bit encodings. But there are 16-bit flag setting
+  // versions of these instructions (adds, movs, etc). In most of the
+  // cases in ART we don't care if the instructions keep flags or not;
+  // thus we can benefit from smaller code size.
+  // VIXL will never generate flag setting versions (for example, adds
+  // for Add macro instruction) unless vixl32::DontCare option is
+  // explicitly specified. That's why we introduce wrappers to use
+  // DontCare option by default.
+#define WITH_FLAGS_DONT_CARE_RD_RN_OP(func_name) \
+  void (func_name)(vixl32::Register rd, vixl32::Register rn, const vixl32::Operand& operand) { \
+    MacroAssembler::func_name(vixl32::DontCare, rd, rn, operand); \
+  } \
+  using MacroAssembler::func_name
+
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Adc);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Sub);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Sbc);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Rsb);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Rsc);
+
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Eor);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Orr);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Orn);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(And);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Bic);
+
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Asr);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Lsr);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Lsl);
+  WITH_FLAGS_DONT_CARE_RD_RN_OP(Ror);
+
+#undef WITH_FLAGS_DONT_CARE_RD_RN_OP
+
+#define WITH_FLAGS_DONT_CARE_RD_OP(func_name) \
+  void (func_name)(vixl32::Register rd, const vixl32::Operand& operand) { \
+    MacroAssembler::func_name(vixl32::DontCare, rd, operand); \
+  } \
+  using MacroAssembler::func_name
+
+  WITH_FLAGS_DONT_CARE_RD_OP(Mvn);
+  WITH_FLAGS_DONT_CARE_RD_OP(Mov);
+
+#undef WITH_FLAGS_DONT_CARE_RD_OP
+
+  // The following two functions don't fall into above categories. Overload them separately.
+  void Rrx(vixl32::Register rd, vixl32::Register rn) {
+    MacroAssembler::Rrx(vixl32::DontCare, rd, rn);
+  }
+  using MacroAssembler::Rrx;
+
+  void Mul(vixl32::Register rd, vixl32::Register rn, vixl32::Register rm) {
+    MacroAssembler::Mul(vixl32::DontCare, rd, rn, rm);
+  }
+  using MacroAssembler::Mul;
+
+  // TODO: Remove when MacroAssembler::Add(FlagsUpdate, Condition, Register, Register, Operand)
+  // makes the right decision about 16-bit encodings.
+  void Add(vixl32::Register rd, vixl32::Register rn, const vixl32::Operand& operand) {
+    if (rd.Is(rn)) {
+      MacroAssembler::Add(rd, rn, operand);
+    } else {
+      MacroAssembler::Add(vixl32::DontCare, rd, rn, operand);
+    }
+  }
+  using MacroAssembler::Add;
+
+  // These interfaces try to use 16-bit T2 encoding of B instruction.
+  void B(vixl32::Label* label);
+  void B(vixl32::Condition cond, vixl32::Label* label);
 };
 
 class ArmVIXLAssembler FINAL : public Assembler {
diff --git a/test/538-checker-embed-constants/src/Main.java b/test/538-checker-embed-constants/src/Main.java
index 0329e63ffd..4f34ec90ea 100644
--- a/test/538-checker-embed-constants/src/Main.java
+++ b/test/538-checker-embed-constants/src/Main.java
@@ -308,7 +308,7 @@ public class Main {
   }
 
   /// CHECK-START-ARM: long Main.shl32(long) disassembly (after)
-  /// CHECK-DAG:            mov {{r\d+}}, {{r\d+}}
+  /// CHECK-DAG:            mov{{s?}} {{r\d+}}, {{r\d+}}
   /// CHECK-DAG:            mov{{s?|\.w}} {{r\d+}}, #0
 
   /// CHECK-START-ARM: long Main.shl32(long) disassembly (after)
@@ -377,7 +377,7 @@ public class Main {
 
   /// CHECK-START-ARM: long Main.shr32(long) disassembly (after)
   /// CHECK-DAG:            asr{{s?|\.w}} {{r\d+}}, <<high:r\d+>>, #31
-  /// CHECK-DAG:            mov {{r\d+}}, <<high>>
+  /// CHECK-DAG:            mov{{s?}} {{r\d+}}, <<high>>
 
   /// CHECK-START-ARM: long Main.shr32(long) disassembly (after)
   /// CHECK-NOT:            asr{{s?|\.w}} {{r\d+}}, {{r\d+}}, {{r\d+}}
@@ -445,7 +445,7 @@ public class Main {
   }
 
   /// CHECK-START-ARM: long Main.ushr32(long) disassembly (after)
-  /// CHECK-DAG:            mov {{r\d+}}, {{r\d+}}
+  /// CHECK-DAG:            mov{{s?}} {{r\d+}}, {{r\d+}}
   /// CHECK-DAG:            mov{{s?|\.w}} {{r\d+}}, #0
 
   /// CHECK-START-ARM: long Main.ushr32(long) disassembly (after)