Maud HTML escaper assembly

main.s

	.text
	.intel_syntax noprefix
	.file	"rust_out.cgu-0.rs"
	.section	".text._ZN40_$LT$alloc..raw_vec..RawVec$LT$T$GT$$GT$6double17h17920b8a90cfe6cfE","ax",@progbits
	.p2align	4, 0x90
	.type	_ZN40_$LT$alloc..raw_vec..RawVec$LT$T$GT$$GT$6double17h17920b8a90cfe6cfE,@function
_ZN40_$LT$alloc..raw_vec..RawVec$LT$T$GT$$GT$6double17h17920b8a90cfe6cfE:
	.cfi_startproc
	push	r14
.Ltmp0:
	.cfi_def_cfa_offset 16
	push	rbx
.Ltmp1:
	.cfi_def_cfa_offset 24
	push	rax
.Ltmp2:
	.cfi_def_cfa_offset 32
.Ltmp3:
	.cfi_offset rbx, -24
.Ltmp4:
	.cfi_offset r14, -16
	mov	rbx, rdi
	mov	rsi, qword ptr [rbx + 8]
	test	rsi, rsi
	je	.LBB0_2
	mov	rdi, qword ptr [rbx]
	lea	r14, [rsi + rsi]
	mov	ecx, 1
	mov	rdx, r14
	call	__rust_reallocate@PLT
	jmp	.LBB0_3
.LBB0_2:
	mov	r14d, 4
	mov	edi, 4
	mov	esi, 1
	call	__rust_allocate@PLT
.LBB0_3:
	test	rax, rax
	je	.LBB0_5
	mov	qword ptr [rbx], rax
	mov	qword ptr [rbx + 8], r14
	add	rsp, 8
	pop	rbx
	pop	r14
	ret
.LBB0_5:
	call	_ZN5alloc3oom3oom17he12d244509df7328E@PLT
.Lfunc_end0:
	.size	_ZN40_$LT$alloc..raw_vec..RawVec$LT$T$GT$$GT$6double17h17920b8a90cfe6cfE, .Lfunc_end0-_ZN40_$LT$alloc..raw_vec..RawVec$LT$T$GT$$GT$6double17h17920b8a90cfe6cfE
	.cfi_endproc

	.section	.text._ZN8rust_out4main17ha208b69ccbc11839E,"ax",@progbits
	.p2align	4, 0x90
	.type	_ZN8rust_out4main17ha208b69ccbc11839E,@function
_ZN8rust_out4main17ha208b69ccbc11839E:
.Lfunc_begin0:
	.cfi_startproc
	.cfi_personality 155, DW.ref.rust_eh_personality
	.cfi_lsda 27, .Lexception0
	push	rbp
.Ltmp25:
	.cfi_def_cfa_offset 16
	push	r15
.Ltmp26:
	.cfi_def_cfa_offset 24
	push	r14
.Ltmp27:
	.cfi_def_cfa_offset 32
	push	r13
.Ltmp28:
	.cfi_def_cfa_offset 40
	push	r12
.Ltmp29:
	.cfi_def_cfa_offset 48
	push	rbx
.Ltmp30:
	.cfi_def_cfa_offset 56
	sub	rsp, 40
.Ltmp31:
	.cfi_def_cfa_offset 96
.Ltmp32:
	.cfi_offset rbx, -56
.Ltmp33:
	.cfi_offset r12, -48
.Ltmp34:
	.cfi_offset r13, -40
.Ltmp35:
	.cfi_offset r14, -32
.Ltmp36:
	.cfi_offset r15, -24
.Ltmp37:
	.cfi_offset rbp, -16
	mov	qword ptr [rsp], 1
	xorps	xmm0, xmm0
	movups	xmmword ptr [rsp + 8], xmm0
	lea	rax, [rip + str.8]
	mov	qword ptr [rsp + 24], rax
	mov	qword ptr [rsp + 32], 3
	lea	rax, [rsp + 24]
	#APP
	#NO_APP
	mov	r13, qword ptr [rsp + 32]
	test	r13, r13
	je	.LBB1_20
	mov	r14, qword ptr [rsp + 24]
	xor	ecx, ecx
	mov	r15d, 335544337
	lea	rbp, [rip + .LJTI1_0]
	lea	r12, [rsp]
	jmp	.LBB1_2
.LBB1_50:
	mov	rsi, qword ptr [rsp + 8]
	mov	rax, rsi
	sub	rax, rcx
	cmp	rax, 4
	jae	.LBB1_51
	add	rcx, 4
	jb	.LBB1_53
	lea	r12, [rsi + rsi]
	cmp	rcx, r12
	cmovae	r12, rcx
	test	rsi, rsi
	je	.LBB1_56
	mov	rdi, qword ptr [rsp]
	mov	ecx, 1
	mov	rdx, r12
	call	__rust_reallocate@PLT
	jmp	.LBB1_58
.LBB1_23:
	mov	rsi, qword ptr [rsp + 8]
	mov	rax, rsi
	sub	rax, rcx
	cmp	rax, 5
	jae	.LBB1_24
	add	rcx, 5
	jb	.LBB1_26
	lea	r12, [rsi + rsi]
	cmp	rcx, r12
	cmovae	r12, rcx
	test	rsi, rsi
	je	.LBB1_29
	mov	rdi, qword ptr [rsp]
	mov	ecx, 1
	mov	rdx, r12
	call	__rust_reallocate@PLT
	jmp	.LBB1_31
.LBB1_36:
	mov	rsi, qword ptr [rsp + 8]
	mov	rax, rsi
	sub	rax, rcx
	cmp	rax, 4
	jae	.LBB1_37
	add	rcx, 4
	jb	.LBB1_39
	lea	r12, [rsi + rsi]
	cmp	rcx, r12
	cmovae	r12, rcx
	test	rsi, rsi
	je	.LBB1_42
	mov	rdi, qword ptr [rsp]
	mov	ecx, 1
	mov	rdx, r12
	call	__rust_reallocate@PLT
	jmp	.LBB1_44
.LBB1_51:
	mov	rax, qword ptr [rsp]
	jmp	.LBB1_62
.LBB1_7:
	mov	rax, qword ptr [rsp]
	jmp	.LBB1_18
.LBB1_24:
	mov	rax, qword ptr [rsp]
	jmp	.LBB1_35
.LBB1_37:
	mov	rax, qword ptr [rsp]
	jmp	.LBB1_48
.LBB1_56:
	mov	esi, 1
	mov	rdi, r12
	call	__rust_allocate@PLT
.LBB1_58:
	test	rax, rax
	je	.LBB1_59
	mov	qword ptr [rsp], rax
	mov	qword ptr [rsp + 8], r12
	mov	rcx, qword ptr [rsp + 16]
	lea	r12, [rsp]
.LBB1_62:
	mov	byte ptr [rax + rcx], 38
	mov	byte ptr [rax + rcx + 1], 108
	jmp	.LBB1_49
.LBB1_12:
	mov	esi, 1
	mov	rdi, r12
	call	__rust_allocate@PLT
.LBB1_14:
	test	rax, rax
	je	.LBB1_15
	mov	qword ptr [rsp], rax
	mov	qword ptr [rsp + 8], r12
	mov	rcx, qword ptr [rsp + 16]
	lea	r12, [rsp]
.LBB1_18:
	mov	byte ptr [rax + rcx], 38
	mov	byte ptr [rax + rcx + 1], 113
	mov	byte ptr [rax + rcx + 2], 117
	mov	byte ptr [rax + rcx + 3], 111
	mov	byte ptr [rax + rcx + 4], 116
	mov	byte ptr [rax + rcx + 5], 59
	add	rcx, 6
	jmp	.LBB1_19
.LBB1_29:
	mov	esi, 1
	mov	rdi, r12
	call	__rust_allocate@PLT
.LBB1_31:
	test	rax, rax
	je	.LBB1_32
	mov	qword ptr [rsp], rax
	mov	qword ptr [rsp + 8], r12
	mov	rcx, qword ptr [rsp + 16]
	lea	r12, [rsp]
.LBB1_35:
	mov	byte ptr [rax + rcx], 38
	mov	byte ptr [rax + rcx + 1], 97
	mov	byte ptr [rax + rcx + 2], 109
	mov	byte ptr [rax + rcx + 3], 112
	mov	byte ptr [rax + rcx + 4], 59
	add	rcx, 5
	jmp	.LBB1_19
.LBB1_42:
	mov	esi, 1
	mov	rdi, r12
	call	__rust_allocate@PLT
.LBB1_44:
	test	rax, rax
	je	.LBB1_45
	mov	qword ptr [rsp], rax
	mov	qword ptr [rsp + 8], r12
	mov	rcx, qword ptr [rsp + 16]
	lea	r12, [rsp]
.LBB1_48:
	mov	byte ptr [rax + rcx], 38
	mov	byte ptr [rax + rcx + 1], 103
.LBB1_49:
	mov	byte ptr [rax + rcx + 2], 116
	mov	byte ptr [rax + rcx + 3], 59
	add	rcx, 4
	jmp	.LBB1_19
	.p2align	4, 0x90
.LBB1_2:
	movzx	ebx, byte ptr [r14]
	mov	eax, ebx
	add	al, -34
	cmp	al, 28
	ja	.LBB1_63
	movzx	edx, al
	bt	r15d, edx
	jae	.LBB1_63
	cmp	al, 28
	ja	.LBB1_63
	movsxd	rax, dword ptr [rbp + 4*rdx]
	add	rax, rbp
	jmp	rax
.LBB1_6:
	mov	rsi, qword ptr [rsp + 8]
	mov	rax, rsi
	sub	rax, rcx
	cmp	rax, 6
	jae	.LBB1_7
	add	rcx, 6
	jb	.LBB1_9
	lea	r12, [rsi + rsi]
	cmp	rcx, r12
	cmovae	r12, rcx
	test	rsi, rsi
	je	.LBB1_12
	mov	rdi, qword ptr [rsp]
	mov	ecx, 1
	mov	rdx, r12
	call	__rust_reallocate@PLT
	jmp	.LBB1_14
	.p2align	4, 0x90
.LBB1_63:
	cmp	rcx, qword ptr [rsp + 8]
	jne	.LBB1_66
.Ltmp22:
	mov	rdi, r12
	call	_ZN40_$LT$alloc..raw_vec..RawVec$LT$T$GT$$GT$6double17h17920b8a90cfe6cfE
.Ltmp23:
	mov	rcx, qword ptr [rsp + 16]
.LBB1_66:
	mov	rax, qword ptr [rsp]
	mov	byte ptr [rax + rcx], bl
	mov	rcx, qword ptr [rsp + 16]
	inc	rcx
.LBB1_19:
	mov	qword ptr [rsp + 16], rcx
	inc	r14
	dec	r13
	jne	.LBB1_2
.LBB1_20:
	lea	rax, [rsp]
	mov	qword ptr [rsp + 24], rax
	lea	rax, [rsp + 24]
	#APP
	#NO_APP
	mov	rsi, qword ptr [rsp + 8]
	test	rsi, rsi
	je	.LBB1_22
	mov	rdi, qword ptr [rsp]
	mov	edx, 1
	call	__rust_deallocate@PLT
.LBB1_22:
	add	rsp, 40
	pop	rbx
	pop	r12
	pop	r13
	pop	r14
	pop	r15
	pop	rbp
	ret
.LBB1_45:
.Ltmp9:
	call	_ZN5alloc3oom3oom17he12d244509df7328E@PLT
.Ltmp10:
.LBB1_39:
.Ltmp11:
	lea	rdi, [rip + str.0]
	mov	esi, 17
	call	_ZN4core6option13expect_failed17h6be288f6c3caa41aE@PLT
.Ltmp12:
.LBB1_59:
.Ltmp5:
	call	_ZN5alloc3oom3oom17he12d244509df7328E@PLT
.Ltmp6:
.LBB1_53:
.Ltmp7:
	lea	rdi, [rip + str.0]
	mov	esi, 17
	call	_ZN4core6option13expect_failed17h6be288f6c3caa41aE@PLT
.Ltmp8:
.LBB1_32:
.Ltmp13:
	call	_ZN5alloc3oom3oom17he12d244509df7328E@PLT
.Ltmp14:
.LBB1_26:
.Ltmp15:
	lea	rdi, [rip + str.0]
	mov	esi, 17
	call	_ZN4core6option13expect_failed17h6be288f6c3caa41aE@PLT
.Ltmp16:
.LBB1_15:
.Ltmp17:
	call	_ZN5alloc3oom3oom17he12d244509df7328E@PLT
.Ltmp18:
.LBB1_9:
.Ltmp19:
	lea	rdi, [rip + str.0]
	mov	esi, 17
	call	_ZN4core6option13expect_failed17h6be288f6c3caa41aE@PLT
.Ltmp20:
.LBB1_68:
.Ltmp21:
	jmp	.LBB1_69
.LBB1_67:
.Ltmp24:
.LBB1_69:
	mov	rbx, rax
	mov	rsi, qword ptr [rsp + 8]
	test	rsi, rsi
	je	.LBB1_71
	mov	rdi, qword ptr [rsp]
	mov	edx, 1
	call	__rust_deallocate@PLT
.LBB1_71:
	mov	rdi, rbx
	call	_Unwind_Resume@PLT
.Lfunc_end1:
	.size	_ZN8rust_out4main17ha208b69ccbc11839E, .Lfunc_end1-_ZN8rust_out4main17ha208b69ccbc11839E
	.cfi_endproc
	.section	.rodata._ZN8rust_out4main17ha208b69ccbc11839E,"a",@progbits
	.p2align	2
.LJTI1_0:
	.long	.LBB1_6-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_23-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_50-.LJTI1_0
	.long	.LBB1_63-.LJTI1_0
	.long	.LBB1_36-.LJTI1_0
	.section	.gcc_except_table,"a",@progbits
	.p2align	2
GCC_except_table1:
.Lexception0:
	.byte	255
	.byte	155
	.byte	41
	.byte	3
	.byte	39
	.long	.Ltmp22-.Lfunc_begin0
	.long	.Ltmp23-.Ltmp22
	.long	.Ltmp24-.Lfunc_begin0
	.byte	0
	.long	.Ltmp9-.Lfunc_begin0
	.long	.Ltmp20-.Ltmp9
	.long	.Ltmp21-.Lfunc_begin0
	.byte	0
	.long	.Ltmp20-.Lfunc_begin0
	.long	.Lfunc_end1-.Ltmp20
	.long	0
	.byte	0
	.p2align	2

	.section	.text.main,"ax",@progbits
	.globl	main
	.p2align	4, 0x90
	.type	main,@function
main:
	.cfi_startproc
	mov	rax, rsi
	mov	rcx, rdi
	lea	rdi, [rip + _ZN8rust_out4main17ha208b69ccbc11839E]
	mov	rsi, rcx
	mov	rdx, rax
	jmp	_ZN3std2rt10lang_start17h5d71a3afaaa4b2ffE@PLT
.Lfunc_end2:
	.size	main, .Lfunc_end2-main
	.cfi_endproc

	.type	str.0,@object
	.section	.rodata.str.0,"a",@progbits
	.p2align	4
str.0:
	.ascii	"capacity overflow"
	.size	str.0, 17

	.type	str.4,@object
	.section	.rodata.str.4,"a",@progbits
str.4:
	.ascii	"<"
	.size	str.4, 4

	.type	str.5,@object
	.section	.rodata.str.5,"a",@progbits
str.5:
	.ascii	">"
	.size	str.5, 4

	.type	str.6,@object
	.section	.rodata.str.6,"a",@progbits
str.6:
	.ascii	"&"
	.size	str.6, 5

	.type	str.7,@object
	.section	.rodata.str.7,"a",@progbits
str.7:
	.ascii	"""
	.size	str.7, 6

	.type	str.8,@object
	.section	.rodata.str.8,"a",@progbits
str.8:
	.zero	3,97
	.size	str.8, 3

	.hidden	DW.ref.rust_eh_personality
	.weak	DW.ref.rust_eh_personality
	.section	.data.DW.ref.rust_eh_personality,"aGw",@progbits,DW.ref.rust_eh_personality,comdat
	.p2align	3
	.type	DW.ref.rust_eh_personality,@object
	.size	DW.ref.rust_eh_personality, 8
DW.ref.rust_eh_personality:
	.quad	rust_eh_personality

	.section	".note.GNU-stack","",@progbits

.Ltmp37 and .LBB1_2 are the good parts. We see that it does two interesting things:

• It checks in advance if the byte is within the range ['"', '>']:

  add	al, -34
  cmp	al, 28
  ja	.LBB1_63

• Then, it uses a bit vector to filter out all but the four characters which need to be escaped:

  mov	r15d, 335544337
  ...
  movzx	edx, al
  bt	r15d, edx
  jae	.LBB1_63

Clever!