1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
| // REQUIRES: arm
// RUN: llvm-mc -arm-add-build-attributes -filetype=obj -triple=armv6m-none-eabi %s -o %t
// RUN: echo "SECTIONS { \
// RUN: . = SIZEOF_HEADERS; \
// RUN: .text_low : { *(.text_low) *(.text_low2) } \
// RUN: .text_high 0x2000000 : { *(.text_high) *(.text_high2) } \
// RUN: } " > %t.script
// RUN: ld.lld --script %t.script %t -o %t2
// RUN: llvm-objdump -d %t2 -triple=armv6m-none-eabi | FileCheck %s
// RUN: ld.lld --script %t.script %t -o %t3 --pie
// RUN: llvm-objdump -d %t3 -triple=armv6m-none-eabi | FileCheck -check-prefix=CHECK-PI %s
// Range extension thunks for Arm Architecture v6m. Only Thumb instructions
// are permitted which limits the access to instructions that can access the
// high registers (r8 - r15), this means that the thunks have to spill
// low registers (r0 - r7) in order to perform the transfer of control.
.syntax unified
.section .text_low, "ax", %progbits
.thumb
.type _start, %function
.balign 4
.globl _start
_start:
bl far
.section .text_high, "ax", %progbits
.globl far
.type far, %function
far:
bx lr
// CHECK: Disassembly of section .text_low:
// CHECK-EMPTY:
// CHECK-NEXT: _start:
// CHECK-NEXT: 94: 00 f0 00 f8 bl #0
// CHECK: __Thumbv6MABSLongThunk_far:
// CHECK-NEXT: 98: 03 b4 push {r0, r1}
// CHECK-NEXT: 9a: 01 48 ldr r0, [pc, #4]
// CHECK-NEXT: 9c: 01 90 str r0, [sp, #4]
// CHECK-NEXT: 9e: 01 bd pop {r0, pc}
// CHECK: a0: 01 00 00 02 .word 0x02000001
// CHECK: Disassembly of section .text_high:
// CHECK-EMPTY:
// CHECK-NEXT: far:
// CHECK-NEXT: 2000000: 70 47 bx lr
// CHECK-PI: Disassembly of section .text_low:
// CHECK-PI-EMPTY:
// CHECK-PI-NEXT: _start:
// CHECK-PI-NEXT: 130: 00 f0 00 f8 bl #0
// CHECK-PI: __Thumbv6MPILongThunk_far:
// CHECK-PI-NEXT: 134: 01 b4 push {r0}
// CHECK-PI-NEXT: 136: 02 48 ldr r0, [pc, #8]
// CHECK-PI-NEXT: 138: 84 46 mov r12, r0
// CHECK-PI-NEXT: 13a: 01 bc pop {r0}
// pc = pc (0x13c + 4) + r12 (1fffec1) = 0x2000001 = .far
// CHECK-PI-NEXT: 13c: e7 44 add pc, r12
// CHECK-PI-NEXT: 13e: c0 46 mov r8, r8
// CHECK-PI: 140: c1 fe ff 01 .word 0x01fffec1
// CHECK-PI: Disassembly of section .text_high:
// CHECK-PI-EMPTY:
// CHECK-PI-NEXT: far:
// CHECK-PI-NEXT: 2000000: 70 47 bx lr
|