rustc -C opt-level=2 --emit asm closure.rs -o closure.s && rustc -C opt-level=2 --emit asm function.rs -o function.s && diff -Naur closure.s function.s

closure_vs_function.diff

--- closure.s	2015-10-11 11:18:44.000000000 +0100
+++ function.s	2015-10-11 11:18:44.000000000 +0100
@@ -1,6 +1,6 @@
 	.section	__TEXT,__text,regular,pure_instructions
 	.align	4, 0x90
-__ZN4main20h7b2594820b9cacc4eaaE:
+__ZN4main20h47f1f4c08b3bd344oaaE:
 Lfunc_begin0:
 	.cfi_startproc
 	.cfi_personality 155, _rust_eh_personality
@@ -13,106 +13,76 @@
 	movq	%rsp, %rbp
 Ltmp8:
 	.cfi_def_cfa_register %rbp
-	pushq	%r15
-	pushq	%r14
 	pushq	%rbx
 	subq	$88, %rsp
 Ltmp9:
-	.cfi_offset %rbx, -40
-Ltmp10:
-	.cfi_offset %r14, -32
-Ltmp11:
-	.cfi_offset %r15, -24
-	movl	$12, %edi
-	movl	$4, %esi
-	callq	___rust_allocate
-	movq	%rax, %r15
-	testq	%r15, %r15
-	je	LBB0_15
-	movl	_const3977+8(%rip), %eax
-	movl	%eax, 8(%r15)
-	movq	_const3977(%rip), %rax
-	movq	%rax, (%r15)
+	.cfi_offset %rbx, -24
 	movl	$12, %edi
 	movl	$4, %esi
 	callq	___rust_allocate
-	movq	%rax, %rbx
-	testq	%rbx, %rbx
-	je	LBB0_2
-	movabsq	$17179869186, %rax
-	movq	%rax, (%rbx)
-	movl	8(%r15), %eax
-	addl	%eax, %eax
-	movl	%eax, 8(%rbx)
-	movl	$12, %esi
-	movl	$4, %edx
-	movq	%r15, %rdi
-	callq	___rust_deallocate
-	movq	%rbx, -112(%rbp)
-	movq	$3, -104(%rbp)
-	movq	$3, -96(%rbp)
-	leaq	__ZN3vec23Vec$LT$T$GT$.fmt..Debug3fmt21h13580533641886887853E(%rip), %rax
-	movq	%rax, -80(%rbp)
-	leaq	-112(%rbp), %rax
-	movq	%rax, -88(%rbp)
-	leaq	_ref4276(%rip), %rax
+	testq	%rax, %rax
+	je	LBB0_1
+	movl	$2, (%rax)
+	movl	$4, 4(%rax)
+	movl	$6, 8(%rax)
+	movq	%rax, -96(%rbp)
+	movq	$3, -88(%rbp)
+	movq	$3, -80(%rbp)
+	leaq	__ZN3vec23Vec$LT$T$GT$.fmt..Debug3fmt20h7846768527019415933E(%rip), %rax
+	movq	%rax, -64(%rbp)
+	leaq	-96(%rbp), %rax
 	movq	%rax, -72(%rbp)
-	movq	$2, -64(%rbp)
-	movq	$0, -48(%rbp)
-	movq	$0, -56(%rbp)
-	leaq	-88(%rbp), %rax
-	movq	%rax, -40(%rbp)
-	movq	$1, -32(%rbp)
+	leaq	_ref4278(%rip), %rax
+	movq	%rax, -56(%rbp)
+	movq	$2, -48(%rbp)
+	movq	$0, -32(%rbp)
+	movq	$0, -40(%rbp)
+	leaq	-72(%rbp), %rax
+	movq	%rax, -24(%rbp)
+	movq	$1, -16(%rbp)
 Ltmp0:
-	leaq	-72(%rbp), %rdi
+	leaq	-56(%rbp), %rdi
 	callq	__ZN2io5stdio6_print20he16d866c4af8e764V5gE
 Ltmp1:
-	movq	-104(%rbp), %rsi
+	movq	-88(%rbp), %rsi
 	testq	%rsi, %rsi
-	je	LBB0_14
+	je	LBB0_12
 	movabsq	$2097865012304223517, %rax
 	cmpq	%rax, %rsi
-	je	LBB0_14
+	je	LBB0_12
 	shlq	$2, %rsi
-	movq	-112(%rbp), %rdi
+	movq	-96(%rbp), %rdi
 	movl	$4, %edx
 	callq	___rust_deallocate
-LBB0_14:
+LBB0_12:
 	addq	$88, %rsp
 	popq	%rbx
-	popq	%r14
-	popq	%r15
 	popq	%rbp
 	retq
-LBB0_15:
-	callq	__ZN3oom20h633c9ae9af23387batbE
-LBB0_2:
+LBB0_1:
 Ltmp3:
 	callq	__ZN3oom20h633c9ae9af23387batbE
 Ltmp4:
-LBB0_7:
+LBB0_5:
 Ltmp2:
-	movq	%rax, %r14
-	movq	-104(%rbp), %rsi
+	movq	%rax, %rbx
+	movq	-88(%rbp), %rsi
 	testq	%rsi, %rsi
-	je	LBB0_6
+	je	LBB0_4
 	movabsq	$2097865012304223517, %rax
 	cmpq	%rax, %rsi
-	je	LBB0_6
+	je	LBB0_4
 	shlq	$2, %rsi
-	movq	-112(%rbp), %rdi
-	movl	$4, %edx
-	jmp	LBB0_5
-LBB0_4:
-Ltmp5:
-	movq	%rax, %r14
-	movl	$12, %esi
+	movq	-96(%rbp), %rdi
 	movl	$4, %edx
-	movq	%r15, %rdi
-LBB0_5:
 	callq	___rust_deallocate
-LBB0_6:
-	movq	%r14, %rdi
+	movq	%rbx, %rdi
+	callq	__Unwind_Resume
+LBB0_3:
+Ltmp5:
+	movq	%rax, %rbx
+LBB0_4:
+	movq	%rbx, %rdi
 	callq	__Unwind_Resume
 Lfunc_end0:
 	.cfi_endproc
@@ -122,9 +92,9 @@
 Lexception0:
 	.byte	255
 	.byte	155
-	.asciz	"\266\200\200"
+	.byte	41
 	.byte	3
-	.byte	52
+	.byte	39
 Lset0 = Ltmp0-Lfunc_begin0
 	.long	Lset0
 Lset1 = Ltmp1-Ltmp0
@@ -132,38 +102,32 @@
 Lset2 = Ltmp2-Lfunc_begin0
 	.long	Lset2
 	.byte	0
-Lset3 = Ltmp1-Lfunc_begin0
+Lset3 = Ltmp3-Lfunc_begin0
 	.long	Lset3
-Lset4 = Ltmp3-Ltmp1
+Lset4 = Ltmp4-Ltmp3
 	.long	Lset4
-	.long	0
-	.byte	0
-Lset5 = Ltmp3-Lfunc_begin0
+Lset5 = Ltmp5-Lfunc_begin0
 	.long	Lset5
-Lset6 = Ltmp4-Ltmp3
+	.byte	0
+Lset6 = Ltmp4-Lfunc_begin0
 	.long	Lset6
-Lset7 = Ltmp5-Lfunc_begin0
+Lset7 = Lfunc_end0-Ltmp4
 	.long	Lset7
-	.byte	0
-Lset8 = Ltmp4-Lfunc_begin0
-	.long	Lset8
-Lset9 = Lfunc_end0-Ltmp4
-	.long	Lset9
 	.long	0
 	.byte	0
 	.align	2
 
 	.section	__TEXT,__text,regular,pure_instructions
 	.align	4, 0x90
-__ZN3vec23Vec$LT$T$GT$.fmt..Debug3fmt21h13580533641886887853E:
+__ZN3vec23Vec$LT$T$GT$.fmt..Debug3fmt20h7846768527019415933E:
 	.cfi_startproc
 	pushq	%rbp
-Ltmp12:
+Ltmp10:
 	.cfi_def_cfa_offset 16
-Ltmp13:
+Ltmp11:
 	.cfi_offset %rbp, -16
 	movq	%rsp, %rbp
-Ltmp14:
+Ltmp12:
 	.cfi_def_cfa_register %rbp
 	pushq	%r15
 	pushq	%r14
@@ -171,15 +135,15 @@
 	pushq	%r12
 	pushq	%rbx
 	subq	$24, %rsp
-Ltmp15:
+Ltmp13:
 	.cfi_offset %rbx, -56
-Ltmp16:
+Ltmp14:
 	.cfi_offset %r12, -48
-Ltmp17:
+Ltmp15:
 	.cfi_offset %r13, -40
-Ltmp18:
+Ltmp16:
 	.cfi_offset %r14, -32
-Ltmp19:
+Ltmp17:
 	.cfi_offset %r15, -24
 	movq	(%rdi), %rbx
 	movq	16(%rdi), %r13
@@ -188,7 +152,7 @@
 	testq	%r13, %r13
 	je	LBB1_3
 	shlq	$2, %r13
-	leaq	_vtable4242(%rip), %r14
+	leaq	_vtable4244(%rip), %r14
 	leaq	-64(%rbp), %r15
 	leaq	-48(%rbp), %r12
 	.align	4, 0x90
@@ -215,19 +179,19 @@
 	.cfi_endproc
 
 	.align	4, 0x90
-__ZN2i89drop.423817hbeebf6ea8e707b19E:
+__ZN2i89drop.424017h394f068857b35ecfE:
 	retq
 
 	.align	4, 0x90
-__ZN3fmt23_$RF$$u27$a$u20$T.Debug3fmt21h14413325998897563779E:
+__ZN3fmt23_$RF$$u27$a$u20$T.Debug3fmt21h14440093934698046107E:
 	.cfi_startproc
 	pushq	%rbp
-Ltmp20:
+Ltmp18:
 	.cfi_def_cfa_offset 16
-Ltmp21:
+Ltmp19:
 	.cfi_offset %rbp, -16
 	movq	%rsp, %rbp
-Ltmp22:
+Ltmp20:
 	.cfi_def_cfa_register %rbp
 	movq	(%rdi), %rdi
 	popq	%rbp
@@ -240,40 +204,33 @@
 	.cfi_startproc
 	movq	%rsi, %rax
 	movq	%rdi, %rcx
-	leaq	__ZN4main20h7b2594820b9cacc4eaaE(%rip), %rdi
+	leaq	__ZN4main20h47f1f4c08b3bd344oaaE(%rip), %rdi
 	movq	%rcx, %rsi
 	movq	%rax, %rdx
 	jmp	__ZN2rt10lang_start20h3a9e1691abb4cd9cfSwE
 	.cfi_endproc
 
-	.section	__TEXT,__const
-	.align	2
-_const3977:
-	.long	1
-	.long	2
-	.long	3
-
 	.section	__DATA,__const
 	.align	4
-_vtable4242:
-	.quad	__ZN2i89drop.423817hbeebf6ea8e707b19E
+_vtable4244:
+	.quad	__ZN2i89drop.424017h394f068857b35ecfE
 	.quad	8
 	.quad	8
-	.quad	__ZN3fmt23_$RF$$u27$a$u20$T.Debug3fmt21h14413325998897563779E
+	.quad	__ZN3fmt23_$RF$$u27$a$u20$T.Debug3fmt21h14440093934698046107E
 
 	.section	__TEXT,__const
-_str4274:
+_str4276:
 	.byte	0
 
-_str4275:
+_str4277:
 	.byte	10
 
 	.section	__DATA,__const
 	.align	4
-_ref4276:
-	.quad	_str4274
+_ref4278:
+	.quad	_str4276
 	.quad	0
-	.quad	_str4275
+	.quad	_str4277
 	.quad	1