forked from OSchip/llvm-project
40 lines
1.4 KiB
ArmAsm
40 lines
1.4 KiB
ArmAsm
// REQUIRES: arm
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// RUN: llvm-mc -arm-add-build-attributes -filetype=obj -triple=armv6m-none-eabi %s -o %t
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// RUN: echo "SECTIONS { \
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// RUN: . = SIZEOF_HEADERS; \
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// RUN: .text_low : { *(.text_low) *(.text_low2) } \
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// RUN: .text_high 0x2000000 : { *(.text_high) *(.text_high2) } \
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// RUN: } " > %t.script
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// RUN: not ld.lld --script %t.script %t -o %t2 2>&1 | FileCheck %s
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// CHECK: error: thunks not supported for architecture Armv6-m
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// Range extension thunks are not currently supported on Armv6-m due to a
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// combination of Armv6-m being aimed at low-end microcontrollers that typically
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// have < 512 Kilobytes of memory, and the restrictions of the instruction set
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// that make thunks inefficient. The main restriction is that the
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// interprocedural scratch register r12 (ip) cannot be accessed from many
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// instructions so we must use the stack to avoid corrupting the program.
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//
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// A v6-m Thunk would look like
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// push {r0, r1} ; Make 8-bytes of stack for restoring r0, and destination
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// ldr r0, [pc, #4] ; L1
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// str r0, [sp, #4] ; store destination address into sp + 4
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// pop {r0, pc} ; restore r0 and load pc with destination
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// L1: .word destination
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.syntax unified
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.section .text_low, "ax", %progbits
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.thumb
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.type _start, %function
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.globl _start
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_start:
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bl far
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.section .text_high, "ax", %progbits
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.globl far
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.type far, %function
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far:
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bx lr
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