arm-bl-v6.s 2.48 KB
// REQUIRES: arm
// RUN: llvm-mc -arm-add-build-attributes -filetype=obj -triple=armv6-none-linux-gnueabi %s -o %t
// RUN: ld.lld %t -o %t2
// RUN: llvm-objdump -d --triple=armv6-none-linux-gnueabi --start-address=0x21000 --stop-address=0x21008 %t2 | FileCheck --check-prefix=CHECK-ARM1 %s
// RUN: llvm-objdump -d --triple=thumbv6-none-linux-gnueabi %t2 --start-address=0x21008 --stop-address=0x2100c | FileCheck --check-prefix=CHECK-THUMB1 %s
// RUN: llvm-objdump -d --triple=armv6-none-linux-gnueabi --start-address=0x22100c --stop-address=0x221014 %t2 | FileCheck --check-prefix=CHECK-ARM2 %s
// RUN: llvm-objdump -d --triple=thumbv6-none-linux-gnueabi %t2 --start-address=0x622000 --stop-address=0x622002 | FileCheck --check-prefix=CHECK-THUMB2 %s

/// On Arm v6 the range of a Thumb BL instruction is only 4 megabytes as the
/// extended range encoding is not supported. The following example has a Thumb
/// BL that is out of range on ARM v6 and requires a range extension thunk.
/// As v6 does not support MOVT or MOVW instructions the Thunk must not
/// use these instructions either.


/// ARM v6 supports blx so we shouldn't see the blx not supported warning.
// CHECK-NOT: warning: lld uses blx instruction, no object with architecture supporting feature detected.
 .text
 .syntax unified
 .cpu    arm1176jzf-s
 .globl _start
 .type   _start,%function
 .balign 0x1000
_start:
  bl thumbfunc
  bx lr

// CHECK-ARM1: Disassembly of section .text:
// CHECK-ARM1-EMPTY:
// CHECK-ARM1-NEXT: <_start>:
// CHECK-ARM1-NEXT:    21000:   00 00 00 fa     blx     #0 <thumbfunc>
// CHECK-ARM1-NEXT:    21004:   1e ff 2f e1     bx      lr
 .thumb
 .section .text.2, "ax", %progbits
 .globl thumbfunc
 .type thumbfunc,%function
thumbfunc:
 bl farthumbfunc

// CHECK-THUMB1: <thumbfunc>:
// CHECK-THUMB1-NEXT:    21008:	00 f2 00 e8 	blx	#2097152
/// 6 Megabytes, enough to make farthumbfunc out of range of caller
/// on a v6 Arm, but not on a v7 Arm.

 .section .text.3, "ax", %progbits
 .space 0x200000
// CHECK-ARM2: <__ARMv5ABSLongThunk_farthumbfunc>:
// CHECK-ARM2-NEXT:   22100c:   04 f0 1f e5     ldr     pc, [pc, #-4]
// CHECK-ARM2: <$d>:
// CHECK-ARM2-NEXT:   221010:   01 20 62 00     .word   0x00622001
 .section .text.4, "ax", %progbits
 .space 0x200000

 .section .text.5, "ax", %progbits
 .space 0x200000

 .thumb
 .section .text.6, "ax", %progbits
 .balign 0x1000
 .globl farthumbfunc
 .type farthumbfunc,%function
farthumbfunc:
 bx lr
// CHECK-THUMB2: <farthumbfunc>:
// CHECK-THUMB2-NEXT:   622000:        70 47   bx      lr