| // 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: not ld.lld --script %t.script %t -o %t2 2>&1 | FileCheck %s |
| |
| // CHECK: error: thunks not supported for architecture Armv6-m |
| |
| // Range extension thunks are not currently supported on Armv6-m due to a |
| // combination of Armv6-m being aimed at low-end microcontrollers that typically |
| // have < 512 Kilobytes of memory, and the restrictions of the instruction set |
| // that make thunks inefficient. The main restriction is that the |
| // interprocedural scratch register r12 (ip) cannot be accessed from many |
| // instructions so we must use the stack to avoid corrupting the program. |
| // |
| // A v6-m Thunk would look like |
| // push {r0, r1} ; Make 8-bytes of stack for restoring r0, and destination |
| // ldr r0, [pc, #4] ; L1 |
| // str r0, [sp, #4] ; store destination address into sp + 4 |
| // pop {r0, pc} ; restore r0 and load pc with destination |
| // L1: .word destination |
| |
| .syntax unified |
| .section .text_low, "ax", %progbits |
| .thumb |
| .type _start, %function |
| .globl _start |
| _start: |
| bl far |
| |
| .section .text_high, "ax", %progbits |
| .globl far |
| .type far, %function |
| far: |
| bx lr |
| |
