Replace String.charAt() with HIR.

Replace String.charAt() with HArrayLength, HBoundsCheck and
HArrayGet. This allows GVN on the HArrayLength and BCE on
the HBoundsCheck as well as using the infrastructure for
HArrayGet, i.e. better handling of constant indexes than
the old intrinsic and using the HArm64IntermediateAddress.

Bug: 28330359
Change-Id: I32bf1da7eeafe82537a60416abf6ac412baa80dc
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 135f0c4..3f8a32a 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -204,10 +204,14 @@
         locations->InAt(1),
         Location::RegisterLocation(calling_convention.GetRegisterAt(1)),
         Primitive::kPrimInt);
-    x86_64_codegen->InvokeRuntime(QUICK_ENTRY_POINT(pThrowArrayBounds),
+    uint32_t entry_point_offset = instruction_->AsBoundsCheck()->IsStringCharAt()
+        ? QUICK_ENTRY_POINT(pThrowStringBounds)
+        : QUICK_ENTRY_POINT(pThrowArrayBounds);
+    x86_64_codegen->InvokeRuntime(entry_point_offset,
                                   instruction_,
                                   instruction_->GetDexPc(),
                                   this);
+    CheckEntrypointTypes<kQuickThrowStringBounds, void, int32_t, int32_t>();
     CheckEntrypointTypes<kQuickThrowArrayBounds, void, int32_t, int32_t>();
   }
 
@@ -4540,11 +4544,11 @@
   CpuRegister obj = obj_loc.AsRegister<CpuRegister>();
   Location index = locations->InAt(1);
   Location out_loc = locations->Out();
+  uint32_t data_offset = CodeGenerator::GetArrayDataOffset(instruction);
 
   Primitive::Type type = instruction->GetType();
   switch (type) {
     case Primitive::kPrimBoolean: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(uint8_t)).Uint32Value();
       CpuRegister out = out_loc.AsRegister<CpuRegister>();
       if (index.IsConstant()) {
         __ movzxb(out, Address(obj,
@@ -4556,7 +4560,6 @@
     }
 
     case Primitive::kPrimByte: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(int8_t)).Uint32Value();
       CpuRegister out = out_loc.AsRegister<CpuRegister>();
       if (index.IsConstant()) {
         __ movsxb(out, Address(obj,
@@ -4568,7 +4571,6 @@
     }
 
     case Primitive::kPrimShort: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(int16_t)).Uint32Value();
       CpuRegister out = out_loc.AsRegister<CpuRegister>();
       if (index.IsConstant()) {
         __ movsxw(out, Address(obj,
@@ -4580,7 +4582,6 @@
     }
 
     case Primitive::kPrimChar: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(uint16_t)).Uint32Value();
       CpuRegister out = out_loc.AsRegister<CpuRegister>();
       if (index.IsConstant()) {
         __ movzxw(out, Address(obj,
@@ -4592,7 +4593,6 @@
     }
 
     case Primitive::kPrimInt: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(int32_t)).Uint32Value();
       CpuRegister out = out_loc.AsRegister<CpuRegister>();
       if (index.IsConstant()) {
         __ movl(out, Address(obj,
@@ -4607,7 +4607,6 @@
       static_assert(
           sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t),
           "art::mirror::HeapReference<art::mirror::Object> and int32_t have different sizes.");
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(int32_t)).Uint32Value();
       // /* HeapReference<Object> */ out =
       //     *(obj + data_offset + index * sizeof(HeapReference<Object>))
       if (kEmitCompilerReadBarrier && kUseBakerReadBarrier) {
@@ -4641,7 +4640,6 @@
     }
 
     case Primitive::kPrimLong: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(int64_t)).Uint32Value();
       CpuRegister out = out_loc.AsRegister<CpuRegister>();
       if (index.IsConstant()) {
         __ movq(out, Address(obj,
@@ -4653,7 +4651,6 @@
     }
 
     case Primitive::kPrimFloat: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(float)).Uint32Value();
       XmmRegister out = out_loc.AsFpuRegister<XmmRegister>();
       if (index.IsConstant()) {
         __ movss(out, Address(obj,
@@ -4665,7 +4662,6 @@
     }
 
     case Primitive::kPrimDouble: {
-      uint32_t data_offset = mirror::Array::DataOffset(sizeof(double)).Uint32Value();
       XmmRegister out = out_loc.AsFpuRegister<XmmRegister>();
       if (index.IsConstant()) {
         __ movsd(out, Address(obj,