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6746907: Improve implicit null check generation

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Add missing implicit null check cases.

Reviewed-by: never
This commit is contained in:
Vladimir Kozlov 2008-09-10 20:44:47 -07:00
parent 659ca734bb
commit 9812da470c
2 changed files with 9 additions and 0 deletions
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2
hotspot/src/share/vm/opto/graphKit.cpp
View file

@ -1212,6 +1212,7 @@ Node* GraphKit::null_check_common(Node* value, BasicType type,
Deoptimization::Action_make_not_entrant,
NULL, "assert_null");
} else {
replace_in_map(value, zerocon(type));
builtin_throw(reason);
}
}
@ -1960,6 +1961,7 @@ Node* GraphKit::null_check_oop(Node* value, Node* *null_control,
// method will be compiled to handle NULLs.
PreserveJVMState pjvms(this);
set_control(*null_control);
replace_in_map(value, null());
uncommon_trap(Deoptimization::Reason_null_check,
Deoptimization::Action_make_not_entrant);
(*null_control) = top(); // NULL path is dead

7
hotspot/src/share/vm/opto/lcm.cpp
View file

@ -58,6 +58,9 @@ void Block::implicit_null_check(PhaseCFG *cfg, Node *proj, Node *val, int allowe
not_null_block = _succs[0];
null_block = _succs[1];
}
while (null_block->is_Empty() == Block::empty_with_goto) {
null_block = null_block->_succs[0];
}
// Search the exception block for an uncommon trap.
// (See Parse::do_if and Parse::do_ifnull for the reason
@ -149,6 +152,10 @@ void Block::implicit_null_check(PhaseCFG *cfg, Node *proj, Node *val, int allowe
const TypePtr *adr_type = NULL; // Do not need this return value here
const Node* base = mach->get_base_and_disp(offset, adr_type);
if (base == NULL || base == NodeSentinel) {
// Narrow oop address doesn't have base, only index
if( val->bottom_type()->isa_narrowoop() &&
MacroAssembler::needs_explicit_null_check(offset) )
continue; // Give up if offset is beyond page size
// cannot reason about it; is probably not implicit null exception
} else {
const TypePtr* tptr = base->bottom_type()->is_ptr();