Add support for int-to-byte in the optimizing compiler.

- Add support for the int-to-byte Dex instruction in the
  optimizing compiler.
- Implement the ARM and Thumb-2 SBFX instructions.
- Generate x86, x86-64 and ARM (but not ARM64) code for
  char to byte, short to byte and int to byte
  HTypeConversion nodes.
- Add related tests to test/422-type-conversion.

Change-Id: Ic8b8911b90d4b5281fad15bcee96bc3ee85dc577

10 files changed, 227 insertions, 0 deletions

diff --git a/compiler/optimizing/builder.cc b/compiler/optimizing/builder.cc
index 4e2f1cd..c29e283 100644
--- a/compiler/optimizing/builder.cc
+++ b/compiler/optimizing/builder.cc
@@ -1002,6 +1002,11 @@ bool HGraphBuilder::AnalyzeDexInstruction(const Instruction& instruction, uint32
       break;
     }
 
+    case Instruction::INT_TO_BYTE: {
+      Conversion_12x(instruction, Primitive::kPrimInt, Primitive::kPrimByte);
+      break;
+    }
+
     case Instruction::ADD_INT: {
       Binop_23x<HAdd>(instruction, Primitive::kPrimInt);
       break;
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index be326dc..0403c5e 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -1348,6 +1348,22 @@ void LocationsBuilderARM::VisitTypeConversion(HTypeConversion* conversion) {
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          locations->SetInAt(0, Location::RequiresRegister());
+          locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap);
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong:
@@ -1410,6 +1426,21 @@ void InstructionCodeGeneratorARM::VisitTypeConversion(HTypeConversion* conversio
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          __ sbfx(out.As<Register>(), in.As<Register>(), 0, 8);
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong:
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index 904e627..0944f4c 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -1282,6 +1282,22 @@ void LocationsBuilderX86::VisitTypeConversion(HTypeConversion* conversion) {
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          locations->SetInAt(0, Location::Any());
+          locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap);
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong:
@@ -1344,6 +1360,29 @@ void InstructionCodeGeneratorX86::VisitTypeConversion(HTypeConversion* conversio
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          if (in.IsRegister()) {
+            __ movsxb(out.As<Register>(), in.As<ByteRegister>());
+          } else if (in.IsStackSlot()) {
+            __ movsxb(out.As<Register>(), Address(ESP, in.GetStackIndex()));
+          } else {
+            DCHECK(in.GetConstant()->IsIntConstant());
+            int32_t value = in.GetConstant()->AsIntConstant()->GetValue();
+            __ movl(out.As<Register>(), Immediate(static_cast<int8_t>(value)));
+          }
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong:
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index f94c28f..a827f99 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -1280,6 +1280,22 @@ void LocationsBuilderX86_64::VisitTypeConversion(HTypeConversion* conversion) {
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          locations->SetInAt(0, Location::Any());
+          locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap);
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong:
@@ -1344,6 +1360,30 @@ void InstructionCodeGeneratorX86_64::VisitTypeConversion(HTypeConversion* conver
   Primitive::Type result_type = conversion->GetResultType();
   Primitive::Type input_type = conversion->GetInputType();
   switch (result_type) {
+    case Primitive::kPrimByte:
+      switch (input_type) {
+        case Primitive::kPrimShort:
+        case Primitive::kPrimInt:
+        case Primitive::kPrimChar:
+          // int-to-byte conversion.
+          if (in.IsRegister()) {
+            __ movsxb(out.As<CpuRegister>(), in.As<CpuRegister>());
+          } else if (in.IsStackSlot()) {
+            __ movsxb(out.As<CpuRegister>(),
+                      Address(CpuRegister(RSP), in.GetStackIndex()));
+          } else {
+            DCHECK(in.GetConstant()->IsIntConstant());
+            __ movl(out.As<CpuRegister>(),
+                    Immediate(static_cast<int8_t>(in.GetConstant()->AsIntConstant()->GetValue())));
+          }
+          break;
+
+        default:
+          LOG(FATAL) << "Unexpected type conversion from " << input_type
+                     << " to " << result_type;
+      }
+      break;
+
     case Primitive::kPrimInt:
       switch (input_type) {
         case Primitive::kPrimLong:
diff --git a/compiler/utils/arm/assembler_arm.h b/compiler/utils/arm/assembler_arm.h
index dca2ab7..911000a 100644
--- a/compiler/utils/arm/assembler_arm.h
+++ b/compiler/utils/arm/assembler_arm.h
@@ -421,6 +421,9 @@ class ArmAssembler : public Assembler {
   virtual void sdiv(Register rd, Register rn, Register rm, Condition cond = AL) = 0;
   virtual void udiv(Register rd, Register rn, Register rm, Condition cond = AL) = 0;
 
+  virtual void sbfx(Register rd, Register rn, uint32_t lsb, uint32_t width,
+                    Condition cond = AL) = 0;
+
   // Load/store instructions.
   virtual void ldr(Register rd, const Address& ad, Condition cond = AL) = 0;
   virtual void str(Register rd, const Address& ad, Condition cond = AL) = 0;
diff --git a/compiler/utils/arm/assembler_arm32.cc b/compiler/utils/arm/assembler_arm32.cc
index c8a57b1..29cbf58 100644
--- a/compiler/utils/arm/assembler_arm32.cc
+++ b/compiler/utils/arm/assembler_arm32.cc
@@ -208,6 +208,25 @@ void Arm32Assembler::udiv(Register rd, Register rn, Register rm, Condition cond)
 }
 
 
+void Arm32Assembler::sbfx(Register rd, Register rn, uint32_t lsb, uint32_t width, Condition cond) {
+  CHECK_NE(rd, kNoRegister);
+  CHECK_NE(rn, kNoRegister);
+  CHECK_NE(cond, kNoCondition);
+  CHECK_LE(lsb, 31U);
+  CHECK(1U <= width && width <= 32U) << width;
+  uint32_t widthminus1 = width - 1;
+
+  int32_t encoding = (static_cast<int32_t>(cond) << kConditionShift) |
+      B26 | B25 | B24 | B23 | B21 |
+      (widthminus1 << 16) |
+      (static_cast<uint32_t>(rd) << 12) |
+      (lsb << 7) |
+      B6 | B4 |
+      static_cast<uint32_t>(rn);
+  Emit(encoding);
+}
+
+
 void Arm32Assembler::ldr(Register rd, const Address& ad, Condition cond) {
   EmitMemOp(cond, true, false, rd, ad);
 }
diff --git a/compiler/utils/arm/assembler_arm32.h b/compiler/utils/arm/assembler_arm32.h
index dbabb99..b582e9e 100644
--- a/compiler/utils/arm/assembler_arm32.h
+++ b/compiler/utils/arm/assembler_arm32.h
@@ -96,6 +96,8 @@ class Arm32Assembler FINAL : public ArmAssembler {
   void sdiv(Register rd, Register rn, Register rm, Condition cond = AL) OVERRIDE;
   void udiv(Register rd, Register rn, Register rm, Condition cond = AL) OVERRIDE;
 
+  void sbfx(Register rd, Register rn, uint32_t lsb, uint32_t width, Condition cond = AL) OVERRIDE;
+
   // Load/store instructions.
   void ldr(Register rd, const Address& ad, Condition cond = AL) OVERRIDE;
   void str(Register rd, const Address& ad, Condition cond = AL) OVERRIDE;
diff --git a/compiler/utils/arm/assembler_thumb2.cc b/compiler/utils/arm/assembler_thumb2.cc
index 053e843..a309e18 100644
--- a/compiler/utils/arm/assembler_thumb2.cc
+++ b/compiler/utils/arm/assembler_thumb2.cc
@@ -264,6 +264,27 @@ void Thumb2Assembler::udiv(Register rd, Register rn, Register rm, Condition cond
 }
 
 
+void Thumb2Assembler::sbfx(Register rd, Register rn, uint32_t lsb, uint32_t width, Condition cond) {
+  CheckCondition(cond);
+  CHECK_LE(lsb, 31U);
+  CHECK(1U <= width && width <= 32U) << width;
+  uint32_t widthminus1 = width - 1;
+  uint32_t imm2 = lsb & (B1 | B0);  // Bits 0-1 of `lsb`.
+  uint32_t imm3 = (lsb & (B4 | B3 | B2)) >> 2;  // Bits 2-4 of `lsb`.
+
+  uint32_t op = 20U /* 0b10100 */;
+  int32_t encoding = B31 | B30 | B29 | B28 | B25 |
+      op << 20 |
+      static_cast<uint32_t>(rn) << 16 |
+      imm3 << 12 |
+      static_cast<uint32_t>(rd) << 8 |
+      imm2 << 6 |
+      widthminus1;
+
+  Emit32(encoding);
+}
+
+
 void Thumb2Assembler::ldr(Register rd, const Address& ad, Condition cond) {
   EmitLoadStore(cond, true, false, false, false, rd, ad);
 }
diff --git a/compiler/utils/arm/assembler_thumb2.h b/compiler/utils/arm/assembler_thumb2.h
index 9ccdef7..1fc842c 100644
--- a/compiler/utils/arm/assembler_thumb2.h
+++ b/compiler/utils/arm/assembler_thumb2.h
@@ -118,6 +118,8 @@ class Thumb2Assembler FINAL : public ArmAssembler {
   void sdiv(Register rd, Register rn, Register rm, Condition cond = AL) OVERRIDE;
   void udiv(Register rd, Register rn, Register rm, Condition cond = AL) OVERRIDE;
 
+  void sbfx(Register rd, Register rn, uint32_t lsb, uint32_t width, Condition cond = AL) OVERRIDE;
+
   // Load/store instructions.
   void ldr(Register rd, const Address& ad, Condition cond = AL) OVERRIDE;
   void str(Register rd, const Address& ad, Condition cond = AL) OVERRIDE;
diff --git a/test/422-type-conversion/src/Main.java b/test/422-type-conversion/src/Main.java
index a4232ed..7c5ddba 100644
--- a/test/422-type-conversion/src/Main.java
+++ b/test/422-type-conversion/src/Main.java
@@ -18,6 +18,12 @@
 // it does compile the method.
 public class Main {
 
+  public static void assertByteEquals(byte expected, byte result) {
+    if (expected != result) {
+      throw new Error("Expected: " + expected + ", found: " + result);
+    }
+  }
+
   public static void assertIntEquals(int expected, int result) {
     if (expected != result) {
       throw new Error("Expected: " + expected + ", found: " + result);
@@ -37,6 +43,10 @@ public class Main {
     charToLong();
 
     longToInt();
+
+    shortToByte();
+    intToByte();
+    charToByte();
   }
 
   private static void byteToLong() {
@@ -115,6 +125,56 @@ public class Main {
     assertLongEquals(-1, $opt$IntToLong($opt$LongToInt(-4294967297L)));  // -(2^32 + 1)
   }
 
+  private static void shortToByte() {
+    assertByteEquals((byte)1, $opt$ShortToByte((short)1));
+    assertByteEquals((byte)0, $opt$ShortToByte((short)0));
+    assertByteEquals((byte)-1, $opt$ShortToByte((short)-1));
+    assertByteEquals((byte)51, $opt$ShortToByte((short)51));
+    assertByteEquals((byte)-51, $opt$ShortToByte((short)-51));
+    assertByteEquals((byte)127, $opt$ShortToByte((short)127));  // 2^7 - 1
+    assertByteEquals((byte)-127, $opt$ShortToByte((short)-127));  // -(2^7 - 1)
+    assertByteEquals((byte)-128, $opt$ShortToByte((short)-128));  // -(2^7)
+    assertByteEquals((byte)-128, $opt$ShortToByte((short)128));  // 2^7
+    assertByteEquals((byte)127, $opt$ShortToByte((short)-129));  // -(2^7 + 1)
+    assertByteEquals((byte)-1, $opt$ShortToByte((short)32767));  // 2^15 - 1
+    assertByteEquals((byte)0, $opt$ShortToByte((short)-32768));  // -(2^15)
+  }
+
+  private static void intToByte() {
+    assertByteEquals((byte)1, $opt$IntToByte(1));
+    assertByteEquals((byte)0, $opt$IntToByte(0));
+    assertByteEquals((byte)-1, $opt$IntToByte(-1));
+    assertByteEquals((byte)51, $opt$IntToByte(51));
+    assertByteEquals((byte)-51, $opt$IntToByte(-51));
+    assertByteEquals((byte)127, $opt$IntToByte(127));  // 2^7 - 1
+    assertByteEquals((byte)-127, $opt$IntToByte(-127));  // -(2^7 - 1)
+    assertByteEquals((byte)-128, $opt$IntToByte(-128));  // -(2^7)
+    assertByteEquals((byte)-128, $opt$IntToByte(128));  // 2^7
+    assertByteEquals((byte)127, $opt$IntToByte(-129));  // -(2^7 + 1)
+    assertByteEquals((byte)-1, $opt$IntToByte(2147483647));  // 2^31 - 1
+    assertByteEquals((byte)0, $opt$IntToByte(-2147483648));  // -(2^31)
+  }
+
+  private static void charToByte() {
+    assertByteEquals((byte)1, $opt$CharToByte((char)1));
+    assertByteEquals((byte)0, $opt$CharToByte((char)0));
+    assertByteEquals((byte)51, $opt$CharToByte((char)51));
+    assertByteEquals((byte)127, $opt$CharToByte((char)127));  // 2^7 - 1
+    assertByteEquals((byte)-128, $opt$CharToByte((char)128));  // 2^7
+    assertByteEquals((byte)-1, $opt$CharToByte((char)32767));  // 2^15 - 1
+    assertByteEquals((byte)-1, $opt$CharToByte((char)65535));  // 2^16 - 1
+
+    assertByteEquals((byte)0, $opt$CharToByte('\u0000'));
+    assertByteEquals((byte)-1, $opt$CharToByte('\uFFFF'));   // 2^16 - 1
+
+    assertByteEquals((byte)-1, $opt$CharToByte((char)-1));
+    assertByteEquals((byte)-51, $opt$CharToByte((char)-51));
+    assertByteEquals((byte)-127, $opt$CharToByte((char)-127));  // -(2^7 - 1)
+    assertByteEquals((byte)-128, $opt$CharToByte((char)-128));  // -(2^7)
+    assertByteEquals((byte)127, $opt$CharToByte((char)-129));  // -(2^7 + 1)
+  }
+
+
   // These methods produce int-to-long Dex instructions.
   static long $opt$ByteToLong(byte a) { return a; }
   static long $opt$ShortToLong(short a) { return a; }
@@ -124,4 +184,9 @@ public class Main {
   // These methods produce long-to-int Dex instructions.
   static int $opt$LongToInt(long a){ return (int)a; }
   static int $opt$LongLiteralToInt(){ return (int)42L; }
+
+  // These methods produce int-to-byte Dex instructions.
+  static byte $opt$ShortToByte(short a){ return (byte)a; }
+  static byte $opt$IntToByte(int a){ return (byte)a; }
+  static byte $opt$CharToByte(char a){ return (byte)a; }
 }