Clean up `Instruction::SizeInCodeUnitsComplexOpcode()`.

And remove code that's dead since
    https://android-review.googlesource.com/3436080 .

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 181943478
Change-Id: Icadd18246bc812fe3c7589172223e632604e146a

2 files changed, 8 insertions, 41 deletions

diff --git a/libdexfile/dex/dex_instruction.cc b/libdexfile/dex/dex_instruction.cc
index c4db658ae1..27feb08d77 100644
--- a/libdexfile/dex/dex_instruction.cc
+++ b/libdexfile/dex/dex_instruction.cc
@@ -63,16 +63,17 @@ bool Instruction::CanFlowThrough() const {
 }
 
 size_t Instruction::SizeInCodeUnitsComplexOpcode() const {
-  const uint16_t* insns = reinterpret_cast<const uint16_t*>(this);
   // Handle special NOP encoded variable length sequences.
-  switch (*insns) {
+  uint16_t inst_data = Fetch16(0);
+  DCHECK_EQ(inst_data & 0xFF, 0) << DumpString(nullptr);
+  switch (inst_data) {
     case kPackedSwitchSignature:
-      return (4 + insns[1] * 2);
+      return (4 + Fetch16(1) * 2);
     case kSparseSwitchSignature:
-      return (2 + insns[1] * 4);
+      return (2 + Fetch16(1) * 4);
     case kArrayDataSignature: {
-      uint16_t element_size = insns[1];
-      uint32_t length = insns[2] | (((uint32_t)insns[3]) << 16);
+      uint16_t element_size = Fetch16(1);
+      uint32_t length = Fetch16(2) | ((static_cast<uint32_t>(Fetch16(3))) << 16);
       // The plus 1 is to round up for odd size and width.
       uint32_t result = (4 + (element_size * length + 1) / 2);
       // This function is used only after the `MethodVerifier` checked that the 32-bit calculation
@@ -82,32 +83,7 @@ size_t Instruction::SizeInCodeUnitsComplexOpcode() const {
       return result;
     }
     default:
-      if ((*insns & 0xFF) == 0) {
-        return 1;  // NOP.
-      } else {
-        LOG(FATAL) << "Unreachable: " << DumpString(nullptr);
-        UNREACHABLE();
-      }
-  }
-}
-
-size_t Instruction::CodeUnitsRequiredForSizeOfComplexOpcode() const {
-  const uint16_t* insns = reinterpret_cast<const uint16_t*>(this);
-  // Handle special NOP encoded variable length sequences.
-  switch (*insns) {
-    case kPackedSwitchSignature:
-      FALLTHROUGH_INTENDED;
-    case kSparseSwitchSignature:
-      return 2;
-    case kArrayDataSignature:
-      return 4;
-    default:
-      if ((*insns & 0xFF) == 0) {
-        return 1;  // NOP.
-      } else {
-        LOG(FATAL) << "Unreachable: " << DumpString(nullptr);
-        UNREACHABLE();
-      }
+      return 1;  // NOP.
   }
 }
 
diff --git a/libdexfile/dex/dex_instruction.h b/libdexfile/dex/dex_instruction.h
index 0f12f45acd..cf676681e0 100644
--- a/libdexfile/dex/dex_instruction.h
+++ b/libdexfile/dex/dex_instruction.h
@@ -225,12 +225,6 @@ class Instruction {
   // Returns the size (in 2 byte code units) of the given instruction format.
   ALWAYS_INLINE static constexpr size_t SizeInCodeUnits(Format format);
 
-  // Code units required to calculate the size of the instruction.
-  size_t CodeUnitsRequiredForSizeComputation() const {
-    const int8_t result = InstructionDescriptorOf(Opcode()).size_in_code_units;
-    return UNLIKELY(result < 0) ? CodeUnitsRequiredForSizeOfComplexOpcode() : 1;
-  }
-
   // Reads an instruction out of the stream at the specified address.
   static const Instruction* At(const uint16_t* code) {
     DCHECK(code != nullptr);
@@ -681,9 +675,6 @@ class Instruction {
     return kInstructionDescriptors[opcode];
   }
 
-  // Return how many code unit words are required to compute the size of the opcode.
-  size_t CodeUnitsRequiredForSizeOfComplexOpcode() const;
-
   uint32_t Fetch32(size_t offset) const {
     return (Fetch16(offset) | ((uint32_t) Fetch16(offset + 1) << 16));
   }