Inlining setters that return one of their arguments.

Useful for builder classes and synthetic setters. The latter
are not inlined yet since they are static methods, i.e. they
don't use "this" as the object for IPUT.

Change-Id: I946cf570195be83ecec5fb32851bcaefad45f8a5

2 files changed, 42 insertions, 18 deletions

diff --git a/runtime/quick/inline_method_analyser.cc b/runtime/quick/inline_method_analyser.cc
index a9072d814c..0a1b72e6b4 100644
--- a/runtime/quick/inline_method_analyser.cc
+++ b/runtime/quick/inline_method_analyser.cc
@@ -218,16 +218,24 @@ bool InlineMethodAnalyser::AnalyseIGetMethod(verifier::MethodVerifier* verifier,
   uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
   DCHECK_GE(object_reg, arg_start);
   DCHECK_LT(object_reg, code_item->registers_size_);
+  uint32_t object_arg = object_reg - arg_start;
+
   DCHECK_LT(opcode == Instruction::IGET_WIDE ? dst_reg + 1 : dst_reg, code_item->registers_size_);
   if (dst_reg != return_reg) {
     return false;  // Not returning the value retrieved by IGET?
   }
 
-  if ((verifier->GetAccessFlags() & kAccStatic) != 0 || object_reg != arg_start) {
+  if ((verifier->GetAccessFlags() & kAccStatic) != 0u || object_arg != 0u) {
     // TODO: Support inlining IGET on other register than "this".
     return false;
   }
 
+  // InlineIGetIPutData::object_arg is only 4 bits wide.
+  static constexpr uint16_t kMaxObjectArg = 15u;
+  if (object_arg > kMaxObjectArg) {
+    return false;
+  }
+
   if (result != nullptr) {
     InlineIGetIPutData* data = &result->d.ifield_data;
     if (!ComputeSpecialAccessorInfo(field_idx, false, verifier, data)) {
@@ -236,10 +244,10 @@ bool InlineMethodAnalyser::AnalyseIGetMethod(verifier::MethodVerifier* verifier,
     result->opcode = kInlineOpIGet;
     result->flags = kInlineSpecial;
     data->op_variant = IGetVariant(opcode);
-    data->object_arg = object_reg - arg_start;  // Allow IGET on any register, not just "this".
+    data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0 ? 1u : 0u;
+    data->object_arg = object_arg;  // Allow IGET on any register, not just "this".
     data->src_arg = 0;
-    data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0;
-    data->reserved = 0;
+    data->return_arg_plus1 = 0u;
   }
   return true;
 }
@@ -253,29 +261,45 @@ bool InlineMethodAnalyser::AnalyseIPutMethod(verifier::MethodVerifier* verifier,
 
   const Instruction* return_instruction = instruction->Next();
   Instruction::Code return_opcode = return_instruction->Opcode();
+  uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
+  uint16_t return_arg_plus1 = 0u;
   if (return_opcode != Instruction::RETURN_VOID) {
-    // TODO: Support returning an argument.
-    // This is needed by builder classes and generated accessor setters.
-    //    builder.setX(value): iput value, this, fieldX; return-object this;
-    //    object.access$nnn(value): iput value, this, fieldX; return value;
-    // Use InlineIGetIPutData::reserved to hold the information.
-    return false;
+    if (return_opcode != Instruction::RETURN &&
+        return_opcode != Instruction::RETURN_OBJECT &&
+        return_opcode != Instruction::RETURN_WIDE) {
+      return false;
+    }
+    // Returning an argument.
+    uint32_t return_reg = return_instruction->VRegA_11x();
+    DCHECK_GE(return_reg, arg_start);
+    DCHECK_LT(return_opcode == Instruction::RETURN_WIDE ? return_reg + 1u : return_reg,
+              code_item->registers_size_);
+    return_arg_plus1 = return_reg - arg_start + 1u;
   }
 
   uint32_t src_reg = instruction->VRegA_22c();
   uint32_t object_reg = instruction->VRegB_22c();
   uint32_t field_idx = instruction->VRegC_22c();
-  uint32_t arg_start = code_item->registers_size_ - code_item->ins_size_;
   DCHECK_GE(object_reg, arg_start);
   DCHECK_LT(object_reg, code_item->registers_size_);
   DCHECK_GE(src_reg, arg_start);
   DCHECK_LT(opcode == Instruction::IPUT_WIDE ? src_reg + 1 : src_reg, code_item->registers_size_);
+  uint32_t object_arg = object_reg - arg_start;
+  uint32_t src_arg = src_reg - arg_start;
 
-  if ((verifier->GetAccessFlags() & kAccStatic) != 0 || object_reg != arg_start) {
+  if ((verifier->GetAccessFlags() & kAccStatic) != 0 || object_arg != 0) {
     // TODO: Support inlining IPUT on other register than "this".
     return false;
   }
 
+  // InlineIGetIPutData::object_arg/src_arg/return_arg_plus1 are each only 4 bits wide.
+  static constexpr uint16_t kMaxObjectArg = 15u;
+  static constexpr uint16_t kMaxSrcArg = 15u;
+  static constexpr uint16_t kMaxReturnArgPlus1 = 15u;
+  if (object_arg > kMaxObjectArg || src_arg > kMaxSrcArg || return_arg_plus1 > kMaxReturnArgPlus1) {
+    return false;
+  }
+
   if (result != nullptr) {
     InlineIGetIPutData* data = &result->d.ifield_data;
     if (!ComputeSpecialAccessorInfo(field_idx, true, verifier, data)) {
@@ -284,10 +308,10 @@ bool InlineMethodAnalyser::AnalyseIPutMethod(verifier::MethodVerifier* verifier,
     result->opcode = kInlineOpIPut;
     result->flags = kInlineSpecial;
     data->op_variant = IPutVariant(opcode);
-    data->object_arg = object_reg - arg_start;  // Allow IPUT on any register, not just "this".
-    data->src_arg = src_reg - arg_start;
-    data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0;
-    data->reserved = 0;
+    data->method_is_static = (verifier->GetAccessFlags() & kAccStatic) != 0 ? 1u : 0u;
+    data->object_arg = object_arg;  // Allow IPUT on any register, not just "this".
+    data->src_arg = src_arg;
+    data->return_arg_plus1 = return_arg_plus1;
   }
   return true;
 }
diff --git a/runtime/quick/inline_method_analyser.h b/runtime/quick/inline_method_analyser.h
index 8e1a4083cd..277a01e502 100644
--- a/runtime/quick/inline_method_analyser.h
+++ b/runtime/quick/inline_method_analyser.h
@@ -98,10 +98,10 @@ struct InlineIGetIPutData {
   // opcode-Instruction::IPUT for IPUTs. This is because the runtime
   // doesn't know the OpSize enumeration.
   uint16_t op_variant : 3;
+  uint16_t method_is_static : 1;
   uint16_t object_arg : 4;
   uint16_t src_arg : 4;  // iput only
-  uint16_t method_is_static : 1;
-  uint16_t reserved : 4;
+  uint16_t return_arg_plus1 : 4;  // iput only, method argument to return + 1, 0 = return void.
   uint16_t field_idx;
   uint32_t is_volatile : 1;
   uint32_t field_offset : 31;