8301047: Clean up type unsafe uses of oop from compiler code

Co-authored-by: Axel Boldt-Christmas <aboldtch@openjdk.org>
Co-authored-by: Stefan Karlsson <stefank@openjdk.org>
Reviewed-by: kvn, stefank

Author: 3 people

src/hotspot/share/code/relocInfo.hpp

@@ -1014,7 +1014,7 @@ class oop_Relocation : public DataRelocation {
 
   void verify_oop_relocation();
 
-  address value() override { return cast_from_oop<address>(*oop_addr()); }
+  address value() override { return *reinterpret_cast<address*>(oop_addr()); }
 
   bool oop_is_immediate()  { return oop_index() == 0; }
 

src/hotspot/share/compiler/oopMap.cpp

@@ -58,8 +58,8 @@ static inline intptr_t derived_pointer_value(derived_pointer p) {
   return static_cast<intptr_t>(p);
 }
 
-static inline derived_pointer to_derived_pointer(oop obj) {
-  return static_cast<derived_pointer>(cast_from_oop<intptr_t>(obj));
+static inline derived_pointer to_derived_pointer(intptr_t obj) {
+  return static_cast<derived_pointer>(obj);
 }
 
 static inline intptr_t operator-(derived_pointer p, derived_pointer p1) {
@@ -414,7 +414,7 @@ class ProcessDerivedOop : public DerivedOopClosure {
     // All derived pointers must be processed before the base pointer of any derived pointer is processed.
     // Otherwise, if two derived pointers use the same base, the second derived pointer will get an obscured
     // offset, if the base pointer is processed in the first derived pointer.
-    derived_pointer derived_base = to_derived_pointer(*base);
+  derived_pointer derived_base = to_derived_pointer(*reinterpret_cast<intptr_t*>(base));
     intptr_t offset = *derived - derived_base;
     *derived = derived_base;
     _oop_cl->do_oop((oop*)derived);
@@ -923,7 +923,7 @@ void DerivedPointerTable::add(derived_pointer* derived_loc, oop *base_loc) {
   assert(*derived_loc != base_loc_as_derived_pointer, "location already added");
   assert(Entry::_list != nullptr, "list must exist");
   assert(is_active(), "table must be active here");
-  intptr_t offset = *derived_loc - to_derived_pointer(*base_loc);
+  intptr_t offset = *derived_loc - to_derived_pointer(*reinterpret_cast<intptr_t*>(base_loc));
   // This assert is invalid because derived pointers can be
   // arbitrarily far away from their base.
   // assert(offset >= -1000000, "wrong derived pointer info");
@@ -954,7 +954,7 @@ void DerivedPointerTable::update_pointers() {
     oop base = **reinterpret_cast<oop**>(derived_loc);
     assert(Universe::heap()->is_in_or_null(base), "must be an oop");
 
-    derived_pointer derived_base = to_derived_pointer(base);
+    derived_pointer derived_base = to_derived_pointer(cast_from_oop<intptr_t>(base));
     *derived_loc = derived_base + offset;
     assert(*derived_loc - derived_base == offset, "sanity check");
 

src/hotspot/share/compiler/oopMap.hpp

@@ -449,12 +449,12 @@ class ImmutableOopMapBuilder {
 
 class SkipNullValue {
 public:
-  static inline bool should_skip(oop val);
+  static inline bool should_skip(void* val);
 };
 
 class IncludeAllValues {
 public:
-  static bool should_skip(oop value) { return false; }
+  static bool should_skip(void* value) { return false; }
 };
 
 template <typename OopFnT, typename DerivedOopFnT, typename ValueFilterT>

src/hotspot/share/compiler/oopMap.inline.hpp

@@ -47,8 +47,8 @@ inline const ImmutableOopMap* ImmutableOopMapPair::get_from(const ImmutableOopMa
   return set->oopmap_at_offset(_oopmap_offset);
 }
 
-inline bool SkipNullValue::should_skip(oop val) {
-  return val == (oop)nullptr || CompressedOops::is_base(val);
+inline bool SkipNullValue::should_skip(void* val) {
+  return val == nullptr || (UseCompressedOops && CompressedOops::is_base(val));
 }
 
 template <typename OopFnT, typename DerivedOopFnT, typename ValueFilterT>
@@ -84,14 +84,15 @@ void OopMapDo<OopFnT, DerivedOopFnT, ValueFilterT>::iterate_oops_do(const frame
       }
       guarantee(loc != nullptr, "missing saved register");
       derived_pointer* derived_loc = (derived_pointer*)loc;
-      oop* base_loc = fr->oopmapreg_to_oop_location(omv.content_reg(), reg_map);
-      // Ignore nullptr oops and decoded nullptr narrow oops which
+      void** base_loc = (void**) fr->oopmapreg_to_location(omv.content_reg(), reg_map);
+
+      // Ignore nullptr oops and decoded null narrow oops which
       // equal to CompressedOops::base() when a narrow oop
       // implicit null check is used in compiled code.
       // The narrow_oop_base could be nullptr or be the address
       // of the page below heap depending on compressed oops mode.
-      if (base_loc != nullptr && *base_loc != (oop)nullptr && !CompressedOops::is_base(*base_loc)) {
-        _derived_oop_fn->do_derived_oop(base_loc, derived_loc);
+      if (base_loc != nullptr && !SkipNullValue::should_skip(*base_loc)) {
+        _derived_oop_fn->do_derived_oop((oop*)base_loc, derived_loc);
       }
     }
   }
@@ -102,7 +103,7 @@ void OopMapDo<OopFnT, DerivedOopFnT, ValueFilterT>::iterate_oops_do(const frame
       OopMapValue omv = oms.current();
       if (omv.type() != OopMapValue::oop_value && omv.type() != OopMapValue::narrowoop_value)
         continue;
-      oop* loc = fr->oopmapreg_to_oop_location(omv.reg(),reg_map);
+      void** loc = (void**) fr->oopmapreg_to_location(omv.reg(),reg_map);
       // It should be an error if no location can be found for a
       // register mentioned as contained an oop of some kind.  Maybe
       // this was allowed previously because value_value items might
@@ -122,7 +123,7 @@ void OopMapDo<OopFnT, DerivedOopFnT, ValueFilterT>::iterate_oops_do(const frame
       }
       guarantee(loc != nullptr, "missing saved register");
       if ( omv.type() == OopMapValue::oop_value ) {
-        oop val = *loc;
+        void* val = *loc;
         if (ValueFilterT::should_skip(val)) { // TODO: UGLY (basically used to decide if we're freezing/thawing continuation)
           // Ignore nullptr oops and decoded nullptr narrow oops which
           // equal to CompressedOops::base() when a narrow oop
@@ -131,7 +132,7 @@ void OopMapDo<OopFnT, DerivedOopFnT, ValueFilterT>::iterate_oops_do(const frame
           // of the page below heap depending on compressed oops mode.
           continue;
         }
-        _oop_fn->do_oop(loc);
+        _oop_fn->do_oop((oop*)loc);
       } else if ( omv.type() == OopMapValue::narrowoop_value ) {
         narrowOop *nl = (narrowOop*)loc;
 #ifndef VM_LITTLE_ENDIAN

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -1063,7 +1063,6 @@ const int      badCodeHeapFreeVal = 0xDD;                   // value used to zap
 // (These must be implemented as #defines because C++ compilers are
 // not obligated to inline non-integral constants!)
 #define       badAddress        ((address)::badAddressVal)
-#define       badOop            (cast_to_oop(::badOopVal))
 #define       badHeapWord       (::badHeapWordVal)
 
 // Default TaskQueue size is 16K (32-bit) or 128K (64-bit)