stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

8014878: Clean up class field layout code

Browse Source 
Rename/remove local variables, re-arrange instance_size calculation, more comments.

Reviewed-by: kvn, coleenp
This commit is contained in:
Aleksey Shipilev 2013-05-20 23:41:27 +04:00
parent 7efa591bee
commit a462587e4b
1 changed files with 27 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

51
hotspot/src/share/vm/classfile/classFileParser.cpp
View File

@ -3121,10 +3121,6 @@ void ClassFileParser::layout_fields(Handle class_loader,
FieldLayoutInfo* info,
TRAPS) {
// get the padding width from the option
// TODO: Ask VM about specific CPU we are running on
int pad_size = ContendedPaddingWidth;
// Field size and offset computation
int nonstatic_field_size = _super_klass() == NULL ? 0 : _super_klass()->nonstatic_field_size();
int next_static_oop_offset;
@ -3137,13 +3133,14 @@ void ClassFileParser::layout_fields(Handle class_loader,
int next_nonstatic_word_offset;
int next_nonstatic_short_offset;
int next_nonstatic_byte_offset;
int next_nonstatic_type_offset;
int first_nonstatic_oop_offset;
int first_nonstatic_field_offset;
int next_nonstatic_field_offset;
int next_nonstatic_padded_offset;
// Count the contended fields by type.
//
// We ignore static fields, because @Contended is not supported for them.
// The layout code below will also ignore the static fields.
int nonstatic_contended_count = 0;
FieldAllocationCount fac_contended;
for (AllFieldStream fs(_fields, _cp); !fs.done(); fs.next()) {
@ -3175,16 +3172,17 @@ void ClassFileParser::layout_fields(Handle class_loader,
next_static_byte_offset = next_static_short_offset +
((fac->count[STATIC_SHORT]) * BytesPerShort);
first_nonstatic_field_offset = instanceOopDesc::base_offset_in_bytes() +
int nonstatic_fields_start = instanceOopDesc::base_offset_in_bytes() +
nonstatic_field_size * heapOopSize;
next_nonstatic_field_offset = first_nonstatic_field_offset;
next_nonstatic_field_offset = nonstatic_fields_start;
// class is contended, pad before all the fields
// Class is contended, pad before all the fields
if (parsed_annotations->is_contended()) {
next_nonstatic_field_offset += pad_size;
next_nonstatic_field_offset += ContendedPaddingWidth;
}
// Compute the non-contended fields count
unsigned int nonstatic_double_count = fac->count[NONSTATIC_DOUBLE] - fac_contended.count[NONSTATIC_DOUBLE];
unsigned int nonstatic_word_count = fac->count[NONSTATIC_WORD] - fac_contended.count[NONSTATIC_WORD];
unsigned int nonstatic_short_count = fac->count[NONSTATIC_SHORT] - fac_contended.count[NONSTATIC_SHORT];
@ -3242,6 +3240,7 @@ void ClassFileParser::layout_fields(Handle class_loader,
compact_fields = false; // Don't compact fields
}
// Rearrange fields for a given allocation style
if( allocation_style == 0 ) {
// Fields order: oops, longs/doubles, ints, shorts/chars, bytes, padded fields
next_nonstatic_oop_offset = next_nonstatic_field_offset;
@ -3282,6 +3281,8 @@ void ClassFileParser::layout_fields(Handle class_loader,
int nonstatic_short_space_offset;
int nonstatic_byte_space_offset;
// Try to squeeze some of the fields into the gaps due to
// long/double alignment.
if( nonstatic_double_count > 0 ) {
int offset = next_nonstatic_double_offset;
next_nonstatic_double_offset = align_size_up(offset, BytesPerLong);
@ -3455,7 +3456,7 @@ void ClassFileParser::layout_fields(Handle class_loader,
// if there is at least one contended field, we need to have pre-padding for them
if (nonstatic_contended_count > 0) {
next_nonstatic_padded_offset += pad_size;
next_nonstatic_padded_offset += ContendedPaddingWidth;
}
// collect all contended groups
@ -3534,7 +3535,7 @@ void ClassFileParser::layout_fields(Handle class_loader,
// the fields within the same contended group are not inter-padded.
// The only exception is default group, which does not incur the
// equivalence, and so requires intra-padding.
next_nonstatic_padded_offset += pad_size;
next_nonstatic_padded_offset += ContendedPaddingWidth;
}
fs.set_offset(real_offset);
@ -3546,7 +3547,7 @@ void ClassFileParser::layout_fields(Handle class_loader,
// subclass fields and/or adjacent object.
// If this was the default group, the padding is already in place.
if (current_group != 0) {
next_nonstatic_padded_offset += pad_size;
next_nonstatic_padded_offset += ContendedPaddingWidth;
}
}
@ -3560,19 +3561,19 @@ void ClassFileParser::layout_fields(Handle class_loader,
// This helps to alleviate memory contention effects for subclass fields
// and/or adjacent object.
if (parsed_annotations->is_contended()) {
notaligned_offset += pad_size;
notaligned_offset += ContendedPaddingWidth;
}
int next_static_type_offset = align_size_up(next_static_byte_offset, wordSize);
int static_field_size = (next_static_type_offset -
int nonstatic_fields_end = align_size_up(notaligned_offset, heapOopSize);
int instance_end = align_size_up(notaligned_offset, wordSize);
int static_fields_end = align_size_up(next_static_byte_offset, wordSize);
int static_field_size = (static_fields_end -
InstanceMirrorKlass::offset_of_static_fields()) / wordSize;
nonstatic_field_size = nonstatic_field_size +
(nonstatic_fields_end - nonstatic_fields_start) / heapOopSize;
next_nonstatic_type_offset = align_size_up(notaligned_offset, heapOopSize );
nonstatic_field_size = nonstatic_field_size + ((next_nonstatic_type_offset
- first_nonstatic_field_offset)/heapOopSize);
next_nonstatic_type_offset = align_size_up(notaligned_offset, wordSize );
int instance_size = align_object_size(next_nonstatic_type_offset / wordSize);
int instance_size = align_object_size(instance_end / wordSize);
assert(instance_size == align_object_size(align_size_up(
(instanceOopDesc::base_offset_in_bytes() + nonstatic_field_size*heapOopSize),
@ -3589,9 +3590,9 @@ void ClassFileParser::layout_fields(Handle class_loader,
_fields,
_cp,
instance_size,
first_nonstatic_field_offset,
next_nonstatic_field_offset,
next_static_type_offset);
nonstatic_fields_start,
nonstatic_fields_end,
static_fields_end);
}
#endif