PPC/s390: [compiler] Don't use Handle<T>::cast in code generator.

Port 6ace4a50

Original Commit Message:

    In debug mode (SLOW_DCHECK), Handle<T>::cast accesses the object to
    check its type.  Obviously we can no longer do that now that we run
    on a background thread.

    problem. I will look into fixing those as well.

R=neis@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: I2140cd7b3e27a6deb24fe3f462d99ad31eeb8276
Reviewed-on: https://chromium-review.googlesource.com/586675Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Jaideep Bajwa <bjaideep@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#46908}

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

@@ -966,8 +966,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
                 Operand(Code::kHeaderSize - kHeapObjectTag));
         __ Call(ip);
       } else {
-        __ Call(Handle<Code>::cast(i.InputHeapObject(0)),
-                RelocInfo::CODE_TARGET);
+        __ Call(i.InputCode(0), RelocInfo::CODE_TARGET);
       }
       RecordCallPosition(instr);
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
@@ -989,8 +988,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
         // We cannot use the constant pool to load the target since
         // we've already restored the caller's frame.
         ConstantPoolUnavailableScope constant_pool_unavailable(tasm());
-        __ Jump(Handle<Code>::cast(i.InputHeapObject(0)),
-                RelocInfo::CODE_TARGET);
+        __ Jump(i.InputCode(0), RelocInfo::CODE_TARGET);
       }
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       frame_access_state()->ClearSPDelta();

src/compiler/s390/code-generator-s390.cc

@@ -1175,8 +1175,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
                 Operand(Code::kHeaderSize - kHeapObjectTag));
         __ Call(ip);
       } else {
-        __ Call(Handle<Code>::cast(i.InputHeapObject(0)),
-                RelocInfo::CODE_TARGET);
+        __ Call(i.InputCode(0), RelocInfo::CODE_TARGET);
       }
       RecordCallPosition(instr);
       frame_access_state()->ClearSPDelta();
@@ -1197,8 +1196,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
         // We cannot use the constant pool to load the target since
         // we've already restored the caller's frame.
         ConstantPoolUnavailableScope constant_pool_unavailable(tasm());
-        __ Jump(Handle<Code>::cast(i.InputHeapObject(0)),
-                RelocInfo::CODE_TARGET);
+        __ Jump(i.InputCode(0), RelocInfo::CODE_TARGET);
       }
       frame_access_state()->ClearSPDelta();
       frame_access_state()->SetFrameAccessToDefault();