d0cdc5ddd7
The AArch64 branch immediate instruction has a 128MiB range. This makes it suitable for use a short range thunk in the same way as short thunks are implemented in Arm and PPC. This patch adds support for short range thunks to AArch64. Adding short range thunk support should mean that OutputSections can grow to nearly 256 MiB in size without needing long-range indirect branches. Differential Revision: https://reviews.llvm.org/D148701
66 lines
1.9 KiB
ArmAsm
66 lines
1.9 KiB
ArmAsm
// REQUIRES: aarch64
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// RUN: split-file %s %t
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// RUN: llvm-mc -filetype=obj -triple=aarch64 %t/asm -o %t.o
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// RUN: ld.lld --script %t/lds %t.o -o %t/out
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// RUN: llvm-objdump -d --no-show-raw-insn --print-imm-hex %t/out | FileCheck %s
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// RUN: llvm-nm --no-sort --special-syms %t/out | FileCheck --check-prefix=NM %s
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//--- asm
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// Check that we have the out of branch range calculation right. The immediate
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// field is signed so we have a slightly higher negative displacement.
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.section .text_low, "ax", %progbits
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.globl _start
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.type _start, %function
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_start:
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// Need thunk to high_target@plt
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bl high_target
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// Need thunk to .text_high+4
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bl .text_high+4
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ret
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.section .text_high, "ax", %progbits
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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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// No Thunk needed as we are within signed immediate range
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bl _start
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ret
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// CHECK: Disassembly of section .text_low:
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// CHECK-EMPTY:
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// CHECK-NEXT: <_start>:
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// CHECK-NEXT: 2000: bl 0x200c <__AArch64AbsLongThunk_high_target>
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// CHECK-NEXT: 2004: bl 0x2010 <__AArch64AbsLongThunk_>
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// CHECK-NEXT: ret
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// CHECK: <__AArch64AbsLongThunk_high_target>:
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// CHECK-NEXT: 200c: b 0x8002000 <high_target>
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// CHECK: <__AArch64AbsLongThunk_>:
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// CHECK-NEXT: 2010: b 0x8002004 <high_target+0x4>
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// CHECK: Disassembly of section .text_high:
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// CHECK-EMPTY:
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// CHECK-NEXT: <high_target>:
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// CHECK-NEXT: 8002000: bl 0x2000 <_start>
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// CHECK-NEXT: ret
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/// Local symbols copied from %t.o
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// NM: t $x.0
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// NM-NEXT: t $x.1
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/// Local thunk symbols.
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// NM-NEXT: t __AArch64AbsLongThunk_high_target
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// NM-NEXT: t $x
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// NM-NEXT: t __AArch64AbsLongThunk_{{$}}
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// NM-NEXT: t $x
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/// Global symbols.
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// NM-NEXT: T _start
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// NM-NEXT: T high_target
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//--- lds
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PHDRS {
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low PT_LOAD FLAGS(0x1 | 0x4);
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high PT_LOAD FLAGS(0x1 | 0x4);
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}
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SECTIONS {
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.text_low 0x2000: { *(.text_low) } :low
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.text_high 0x8002000 : { *(.text_high) } :high
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}
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