ObjFW  Check-in [943cf97843]

Overview
Comment:Only use 4 bits to classify tagged pointers

This leaves 28/60 bits for the value.

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SHA3-256: 943cf978435fc8205f6a6c609138d2ac51f6353deb7ab33c35010bdb77cf06fc
User & Date: js on 2020-07-04 00:24:54
Other Links: branch diff | manifest | tags
Context
2020-07-04
00:40
Use a regular int for the tagged pointer class ID check-in: a8d453813c user: js tags: tagged-pointers
00:24
Only use 4 bits to classify tagged pointers check-in: 943cf97843 user: js tags: tagged-pointers
2020-07-01
21:32
Merge trunk into branch "tagged-pointers" check-in: 6d5cc25f0c user: js tags: tagged-pointers
Changes
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Modified src/runtime/lookup-asm/lookup-asm-x86-elf.S from [c25a1420f7] to [6468f2e74c].

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0:
	call	get_eip
	add	eax, offset _GLOBAL_OFFSET_TABLE_
	lea	eax, [eax+\not_found@GOTOFF]
	jmp	eax

.Ltagged_pointer_\name:


	movzx	edx, dl
	shr	edx, 1

	call	get_eip
	add	eax, offset _GLOBAL_OFFSET_TABLE_

	lea	eax, [eax+objc_tagged_pointer_classes@GOTOFF]
	mov	edx, [eax+edx*4]
	mov	edx, [edx+32]








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0:
	call	get_eip
	add	eax, offset _GLOBAL_OFFSET_TABLE_
	lea	eax, [eax+\not_found@GOTOFF]
	jmp	eax

.Ltagged_pointer_\name:
	and	dl, 0xF
	shr	dl, 1
	movzx	edx, dl


	call	get_eip
	add	eax, offset _GLOBAL_OFFSET_TABLE_

	lea	eax, [eax+objc_tagged_pointer_classes@GOTOFF]
	mov	edx, [eax+edx*4]
	mov	edx, [edx+32]
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Modified src/runtime/lookup-asm/lookup-asm-x86-win32.S from [db823a1fe8] to [6bf3eb314e].

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	test	eax, eax
	jz	\not_found

	ret

.Ltagged_pointer_\name:


	movzx	edx, dl
	shr	edx, 1

	mov	eax, offset _objc_tagged_pointer_classes
	mov	edx, [eax+edx*4]
	mov	edx, [edx+32]

	jmp	short .Lmain_\name
.endm








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	test	eax, eax
	jz	\not_found

	ret

.Ltagged_pointer_\name:
	and	dl, 0xF
	shr	dl, 1
	movzx	edx, dl


	mov	eax, offset _objc_tagged_pointer_classes
	mov	edx, [eax+edx*4]
	mov	edx, [edx+32]

	jmp	short .Lmain_\name
.endm
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Modified src/runtime/lookup-asm/lookup-asm-x86_64-elf.S from [14d6290458] to [00fefd9a7f].

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	test	rax, rax
	jz	short \not_found@PLT

	ret

.Ltagged_pointer_\name:


	movzx	r8, dil
	shr	r8, 1

	mov	rax, [rip+objc_tagged_pointer_classes@GOTPCREL]
	mov	r8, [rax+r8*8]
	mov	r8, [r8+64]

	jmp	short .Lmain_\name
.type \name, %function








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	test	rax, rax
	jz	short \not_found@PLT

	ret

.Ltagged_pointer_\name:
	and	dil, 0xF
	shr	dil, 1
	movzx	r8, dil


	mov	rax, [rip+objc_tagged_pointer_classes@GOTPCREL]
	mov	r8, [rax+r8*8]
	mov	r8, [r8+64]

	jmp	short .Lmain_\name
.type \name, %function
︙︙

Modified src/runtime/lookup-asm/lookup-asm-x86_64-win64.S from [c889c864a2] to [069968302a].

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0:
	mov	rcx, r10
	mov	rdx, r11
	jmp	\not_found

.Ltagged_pointer_\name:


	movzx	r8, cl
	shr	r8, 1

	mov	rax, offset objc_tagged_pointer_classes
	mov	r8, [rax+r8*8]
	mov	r8, [r8+56]

	jmp	short .Lmain_\name
.endm








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0:
	mov	rcx, r10
	mov	rdx, r11
	jmp	\not_found

.Ltagged_pointer_\name:
	and	cl, 0xF
	shr	cl, 1
	movzx	r8, cl


	mov	rax, offset objc_tagged_pointer_classes
	mov	r8, [rax+r8*8]
	mov	r8, [r8+56]

	jmp	short .Lmain_\name
.endm
︙︙

Modified src/runtime/tagged-pointer.m from [3ba8d16fba] to [1f64e311ce].

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 * file.
 */

#import "ObjFWRT.h"

#import "private.h"


#define NUM_TAGGED_POINTER_CLASSES 0x7F

Class objc_tagged_pointer_classes[NUM_TAGGED_POINTER_CLASSES];
static uint_fast8_t taggedPointerClassesCount;

int_fast8_t
objc_registerTaggedPointerClass(Class class)
{








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 * file.
 */

#import "ObjFWRT.h"

#import "private.h"

#define TAGGED_POINTER_BITS 4
#define NUM_TAGGED_POINTER_CLASSES (1 << (TAGGED_POINTER_BITS - 1))

Class objc_tagged_pointer_classes[NUM_TAGGED_POINTER_CLASSES];
static uint_fast8_t taggedPointerClassesCount;

int_fast8_t
objc_registerTaggedPointerClass(Class class)
{
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}

Class
object_getTaggedPointerClass(id object)
{
	uintptr_t pointer = (uintptr_t)object;

	pointer &= 0x7E;
	pointer >>= 1;

	if (pointer >= NUM_TAGGED_POINTER_CLASSES)
		return Nil;

	return objc_tagged_pointer_classes[pointer];
}

uintptr_t
object_getTaggedPointerValue(id object)
{
	uintptr_t pointer = (uintptr_t)object;

	pointer &= ~(uintptr_t)0xFF;
	pointer >>= 8;

	return pointer;
}

id
objc_createTaggedPointer(uint_fast8_t class, uintptr_t value)
{
	uintptr_t pointer;

	if (class >= NUM_TAGGED_POINTER_CLASSES)
		return nil;

	if (value > (UINTPTR_MAX >> 8))
		return nil;

	pointer = (class << 1) | 1;
	pointer |= (value << 8);

	return (id)pointer;
}








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}

Class
object_getTaggedPointerClass(id object)
{
	uintptr_t pointer = (uintptr_t)object;

	pointer &= (1 << TAGGED_POINTER_BITS) - 1;
	pointer >>= 1;

	if (pointer >= NUM_TAGGED_POINTER_CLASSES)
		return Nil;

	return objc_tagged_pointer_classes[pointer];
}

uintptr_t
object_getTaggedPointerValue(id object)
{
	uintptr_t pointer = (uintptr_t)object;


	pointer >>= TAGGED_POINTER_BITS;

	return pointer;
}

id
objc_createTaggedPointer(uint_fast8_t class, uintptr_t value)
{
	uintptr_t pointer;

	if (class >= NUM_TAGGED_POINTER_CLASSES)
		return nil;

	if (value > (UINTPTR_MAX >> TAGGED_POINTER_BITS))
		return nil;

	pointer = (class << 1) | 1;
	pointer |= (value << TAGGED_POINTER_BITS);

	return (id)pointer;
}

Fossil 2.23 [47362306a7] 2023-11-01 18:56:47
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