comparing this to NULL in HS - code - was : 8208604: Metadata::print_value_string() compares 'this' to NULL

[Baesken, Matthias]

Hello,

seems we have still quite a few places in  the  HS   C++ codebase where "this" is compared to NULL.

Recently  8208604: Metadata::print_value_string() compares 'this' to NULL  :
https://bugs.openjdk.java.net/browse/JDK-8208604
fixed one place and stated :
"The compiler is free to elide this test, since (this == NULL) can never be true; applying an ordinary member function to NULL invokes undefined behavior. "


Should we change  the other checks as well ?

Thanks, Matthias

I found these checks :


jdk/src/hotspot/share/adlc/formssel.cpp

1727bool Opcode::print_opcode(FILE *fp, Opcode::opcode_type desired_opcode) {
1728  // Default values previously provided by MachNode::primary()...
1729  const char *description = NULL;
1730  const char *value       = NULL;
1731  // Check if user provided any opcode definitions
1732  if( this != NULL ) {


3417void MatchNode::count_instr_names( Dict &names ) {
3418  if( this == NULL ) return;


jdk/src/hotspot/share/opto/chaitin.cpp

2147char *PhaseChaitin::dump_register( const Node *n, char *buf  ) const {
2148  if( this == NULL ) {          // Not got anything?
2149    sprintf(buf,"N%d",n->_idx); // Then use Node index
2150  } else if( _node_regs ) {


jdk/src/hotspot/share/asm/codeBuffer.cpp

1241void CodeBuffer::print() {
1242  if (this == NULL) {
1243    tty->print_cr("NULL CodeBuffer pointer");

jdk/src/hotspot/share/runtime/perfData.cpp

593PerfData* PerfDataList::find_by_name(const char* name) {
594
595  // if add_item hasn't been called the list won't be initialized
596  if (this == NULL)
597    return NULL;

jdk/src/hotspot/share/libadt/set.cpp

58char *Set::setstr() const
59{
60  if( this == NULL ) return os::strdup("{no set}");


jdk/src/hotspot/share/oops/symbol.cpp

295void Symbol::print_on(outputStream* st) const {
296  if (this == NULL) {
297    st->print_cr("NULL");

308void Symbol::print_value_on(outputStream* st) const {
309  if (this == NULL) {
310    st->print("NULL");