a8656c62f5
Older Arm architectures do not support the MOVT and MOVW instructions so we must use an alternative sequence of instructions to transfer control to the destination. Assuming at least Armv5 this patch adds support for Thunks that load or add to the program counter. Note that there are no Armv5 Thumb Thunks as there is no Thumb branch instruction in Armv5 that supports Thunks. These thunks will not work for Armv4t (arm7tdmi) as this architecture cannot change state from using the LDR or ADD instruction. Differential Revision: https://reviews.llvm.org/D50077 llvm-svn: 340160
79 lines
2.7 KiB
ArmAsm
79 lines
2.7 KiB
ArmAsm
// REQUIRES: arm
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// RUN: llvm-mc -arm-add-build-attributes -filetype=obj -triple=armv7a-none-linux-gnueabi %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: ld.lld --script %t.script %t -o %t2 2>&1
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// RUN: llvm-objdump -d -triple=thumbv7a-none-linux-gnueabi %t2 | FileCheck %s
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// Simple test that we can support range extension thunks with linker scripts
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.syntax unified
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.section .text_low, "ax", %progbits
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.thumb
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.globl _start
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_start: bx lr
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.globl low_target
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.type low_target, %function
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low_target:
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bl high_target
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bl high_target2
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.section .text_low2, "ax", %progbits
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.thumb
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.globl low_target2
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.type low_target2, %function
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low_target2:
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bl high_target
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bl high_target2
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// CHECK: Disassembly of section .text_low:
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// CHECK-NEXT: _start:
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// CHECK-NEXT: 94: 70 47 bx lr
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// CHECK: low_target:
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// CHECK-NEXT: 96: 00 f0 03 f8 bl #6
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// CHECK-NEXT: 9a: 00 f0 06 f8 bl #12
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// CHECK: __Thumbv7ABSLongThunk_high_target:
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// CHECK-NEXT: a0: 40 f2 01 0c movw r12, #1
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// CHECK-NEXT: a4: c0 f2 00 2c movt r12, #512
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// CHECK-NEXT: a8: 60 47 bx r12
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// CHECK: __Thumbv7ABSLongThunk_high_target2:
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// CHECK-NEXT: aa: 40 f2 1d 0c movw r12, #29
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// CHECK-NEXT: ae: c0 f2 00 2c movt r12, #512
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// CHECK-NEXT: b2: 60 47 bx r12
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// CHECK: low_target2:
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// CHECK-NEXT: b4: ff f7 f4 ff bl #-24
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// CHECK-NEXT: b8: ff f7 f7 ff bl #-18
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.section .text_high, "ax", %progbits
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.thumb
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.globl high_target
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.type high_target, %function
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high_target:
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bl low_target
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bl low_target2
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.section .text_high2, "ax", %progbits
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.thumb
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.globl high_target2
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.type high_target2, %function
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high_target2:
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bl low_target
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bl low_target2
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// CHECK: Disassembly of section .text_high:
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// CHECK-NEXT: high_target:
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// CHECK-NEXT: 2000000: 00 f0 02 f8 bl #4
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// CHECK-NEXT: 2000004: 00 f0 05 f8 bl #10
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// CHECK: __Thumbv7ABSLongThunk_low_target:
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// CHECK-NEXT: 2000008: 40 f2 97 0c movw r12, #151
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// CHECK-NEXT: 200000c: c0 f2 00 0c movt r12, #0
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// CHECK-NEXT: 2000010: 60 47 bx r12
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// CHECK: __Thumbv7ABSLongThunk_low_target2:
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// CHECK-NEXT: 2000012: 40 f2 b5 0c movw r12, #181
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// CHECK-NEXT: 2000016: c0 f2 00 0c movt r12, #0
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// CHECK-NEXT: 200001a: 60 47 bx r12
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// CHECK: high_target2:
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// CHECK-NEXT: 200001c: ff f7 f4 ff bl #-24
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// CHECK-NEXT: 2000020: ff f7 f7 ff bl #-18
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