archive/jdk
1
0
Fork 0
mirror of https://github.com/openjdk/jdk.git synced 2025-09-16 00:54:38 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

6791178: Specialize for zero as the compressed oop vm heap base

Browse source 
Use zero based compressed oops if java heap is below 32gb and unscaled compressed oops if java heap is below 4gb.

Reviewed-by: never, twisti, jcoomes, coleenp
This commit is contained in:
Vladimir Kozlov 2009-03-12 10:37:46 -07:00
parent 66cecec230
commit 69f9ddee90
45 changed files with 1072 additions and 220 deletions
Download patch file Download diff file Expand all files Collapse all files

11
hotspot/src/share/vm/asm/assembler.cpp
View file

@ -321,16 +321,19 @@ void AbstractAssembler::block_comment(const char* comment) {
bool MacroAssembler::needs_explicit_null_check(intptr_t offset) {
// Exception handler checks the nmethod's implicit null checks table
// only when this method returns false.
if (UseCompressedOops) {
#ifdef _LP64
if (UseCompressedOops && Universe::narrow_oop_base() != NULL) {
assert (Universe::heap() != NULL, "java heap should be initialized");
// The first page after heap_base is unmapped and
// the 'offset' is equal to [heap_base + offset] for
// narrow oop implicit null checks.
uintptr_t heap_base = (uintptr_t)Universe::heap_base();
if ((uintptr_t)offset >= heap_base) {
uintptr_t base = (uintptr_t)Universe::narrow_oop_base();
if ((uintptr_t)offset >= base) {
// Normalize offset for the next check.
offset = (intptr_t)(pointer_delta((void*)offset, (void*)heap_base, 1));
offset = (intptr_t)(pointer_delta((void*)offset, (void*)base, 1));
}
}
#endif
return offset < 0 || os::vm_page_size() <= offset;
}