PPC: [Atomics] Remove Atomics code stubs; use TF ops

src/compiler/ppc/code-generator-ppc.cc

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index 2bf4860d4d7030cb8c7627cb8f176fe2e2400e55..8fda2569b8ef074d4b67d546a739df4a2d5b41d0 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -672,6 +672,20 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
     DCHECK_EQ(LeaveRC, i.OutputRCBit());                      \
   } while (0)
 
+#define ASSEMBLE_ATOMIC_LOAD_INTEGER(asm_instr, asm_instrx)           \
+  do {                                                                \
+    AddressingMode mode = kMode_None;                         \
+    DCHECK_EQ(kMode_MRR, mode);                               \
+    if (mode == kMode_MRI) {                                  \
+    __ asm_instr(i.OutputRegister(),                                  \
+                 MemOperand(i.InputRegister(0), i.InputRegister(1))); \

[MTBrandyberry, 2016/04/19 14:13:08]

If you want to support the non-indexed load form here, take a look at how other
paths contruct the MemOperand with i.MemoryOperand (see ASSEMBLE_LOAD_FLOAT for
an example).

+    } else {                                                  \
+    __ asm_instrx(i.OutputRegister(),                                  \
+                 MemOperand(i.InputRegister(0), i.InputRegister(1))); \
+    }                                                         \
+    __ lwsync();                                                      \

[MTBrandyberry, 2016/04/19 14:13:08]

Joran was going to get another opinion on correctness, but for now let's go with
the documented sequence
   [sync;  <load>; cmp; bc; isync]
implemented in the CL prior to this refactor.  See ASSEMBLE_ATOMIC_LOAD here:
https://codereview.chromium.org/1902433003/diff/20001/src/ppc/code-stubs-ppc.cc

+  } while (0)
+
 void CodeGenerator::AssembleDeconstructFrame() {
   __ LeaveFrame(StackFrame::MANUAL);
 }
@@ -1585,6 +1599,23 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kCheckedStoreFloat64:
       ASSEMBLE_CHECKED_STORE_DOUBLE();
       break;
+
+    case kAtomicLoadInt8:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lbz, lbzx);
+      __ extsb(i.OutputRegister(), i.OutputRegister());
+      break;
+    case kAtomicLoadUint8:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lbz, lbzx);
+      break;
+    case kAtomicLoadInt16:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lha, lhax);
+      break;
+    case kAtomicLoadUint16:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lhz, lhzx);
+      break;
+    case kAtomicLoadWord32:
+      ASSEMBLE_ATOMIC_LOAD_INTEGER(lwa, lwax);
+      break;
     default:
       UNREACHABLE();
       break;