PPC/s390: [ubsan] Let Runtime functions return a plain Address

Port f1cb51ad

Original Commit Message:

    instead of Object* (which is deprecated) or ObjectPtr (which is
    unsuitable for cases where we need to control the ABI exactly).
    Callers in generated code expect a plain tagged value, so return
    precisely that. Same for C++ Builtins.

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

Change-Id: I8055c9a9c99dbe8716f810c6b6cc1967bed9c3de
Reviewed-on: https://chromium-review.googlesource.com/c/1393920Reviewed-by: Joran Siu <joransiu@ca.ibm.com>
Commit-Queue: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#58531}

src/ppc/simulator-ppc.cc

@@ -948,23 +948,10 @@ bool Simulator::OverflowFrom(int32_t alu_out, int32_t left, int32_t right,
   return overflow;
 }
 
-
-#if V8_TARGET_ARCH_PPC64
-static void decodeObjectPair(ObjectPair* pair, intptr_t* x, intptr_t* y) {
-  *x = reinterpret_cast<intptr_t>(pair->x);
-  *y = reinterpret_cast<intptr_t>(pair->y);
-}
-#else
 static void decodeObjectPair(ObjectPair* pair, intptr_t* x, intptr_t* y) {
-#if V8_TARGET_BIG_ENDIAN
-  *x = static_cast<int32_t>(*pair >> 32);
-  *y = static_cast<int32_t>(*pair);
-#else
-  *x = static_cast<int32_t>(*pair);
-  *y = static_cast<int32_t>(*pair >> 32);
-#endif
+  *x = static_cast<intptr_t>(pair->x);
+  *y = static_cast<intptr_t>(pair->y);
 }
-#endif
 
 // Calls into the V8 runtime.
 typedef intptr_t (*SimulatorRuntimeCall)(intptr_t arg0, intptr_t arg1,

src/s390/simulator-s390.cc

@@ -1795,22 +1795,10 @@ bool Simulator::OverflowFromSigned(T1 alu_out, T1 left, T1 right,
   return overflow;
 }
 
-#if V8_TARGET_ARCH_S390X
 static void decodeObjectPair(ObjectPair* pair, intptr_t* x, intptr_t* y) {
-  *x = reinterpret_cast<intptr_t>(pair->x);
-  *y = reinterpret_cast<intptr_t>(pair->y);
+  *x = static_cast<intptr_t>(pair->x);
+  *y = static_cast<intptr_t>(pair->y);
 }
-#else
-static void decodeObjectPair(ObjectPair* pair, intptr_t* x, intptr_t* y) {
-#if V8_TARGET_BIG_ENDIAN
-  *x = static_cast<int32_t>(*pair >> 32);
-  *y = static_cast<int32_t>(*pair);
-#else
-  *x = static_cast<int32_t>(*pair);
-  *y = static_cast<int32_t>(*pair >> 32);
-#endif
-}
-#endif
 
 // Calls into the V8 runtime.
 typedef intptr_t (*SimulatorRuntimeCall)(intptr_t arg0, intptr_t arg1,