diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp --- a/lld/ELF/Relocations.cpp +++ b/lld/ELF/Relocations.cpp @@ -2042,7 +2042,8 @@ // out in the relocation addend. We compensate for the PC bias so that // an Arm and Thumb relocation to the same destination get the same keyAddend, // which is usually 0. - int64_t keyAddend = rel.addend + getPCBias(rel.type); + const int64_t pcBias = getPCBias(rel.type); + const int64_t keyAddend = rel.addend + pcBias; // We use a ((section, offset), addend) pair to find the thunk position if // possible so that we create only one thunk for aliased symbols or ICFed @@ -2061,7 +2062,7 @@ if (isThunkSectionCompatible(isec, t->getThunkTargetSym()->section) && t->isCompatibleWith(*isec, rel) && target->inBranchRange(rel.type, src, - t->getThunkTargetSym()->getVA(rel.addend))) + t->getThunkTargetSym()->getVA(-pcBias))) return std::make_pair(t, false); // No existing compatible Thunk in range, create a new one diff --git a/lld/test/ELF/aarch64-thunk-reuse.s b/lld/test/ELF/aarch64-thunk-reuse.s new file mode 100644 --- /dev/null +++ b/lld/test/ELF/aarch64-thunk-reuse.s @@ -0,0 +1,49 @@ +# REQUIRES: aarch64 +# RUN: rm -rf %t && split-file %s %t +# RUN: llvm-mc -filetype=obj -triple=aarch64 %t/a.s -o %t/a.o +# RUN: ld.lld -pie -T %t/lds %t/a.o -o %t/a +# RUN: llvm-objdump -d --no-show-raw-insn %t/a | FileCheck %s + +## We create a thunk for dest. +# CHECK-LABEL: : +# CHECK-NEXT: 8010008: b 0x801000c <__AArch64ADRPThunk_> +# CHECK-EMPTY: +# CHECK-NEXT: <__AArch64ADRPThunk_>: +# CHECK-NEXT: 801000c: adrp x16, 0x10000 +# CHECK-NEXT: add x16, x16, #4 +# CHECK-NEXT: br x16 + +## The first instruction can reuse the thunk but the second can't. +## If we reuse the thunk for b, we will get an "out of range" error. +# CHECK-LABEL: : +# CHECK-NEXT: 1001000c: bl 0x801000c <__AArch64ADRPThunk_> +# CHECK-NEXT: b 0x10010014 <__AArch64ADRPThunk_> +# CHECK-EMPTY: +# CHECK-NEXT: <__AArch64ADRPThunk_>: +# CHECK-NEXT: 10010014: adrp x16, 0x10000 +# CHECK-NEXT: add x16, x16, #4 +# CHECK-NEXT: br x16 + +#--- a.s +.section .text_low, "ax", %progbits +.globl _start +_start: + nop +dest: + ret + +.section .text_mid, "ax", %progbits +mid: + b dest + +.section .text_high, "ax", %progbits +high: + bl dest + b dest + +#--- lds +SECTIONS { + .text_low 0x10000: { *(.text_low) } + .text_mid 0x8010008 : { *(.text_mid) } + .text_high 0x1001000c : { *(.text_high) } +} diff --git a/lld/test/ELF/arm-thunk-reuse.s b/lld/test/ELF/arm-thunk-reuse.s new file mode 100644 --- /dev/null +++ b/lld/test/ELF/arm-thunk-reuse.s @@ -0,0 +1,52 @@ +# REQUIRES: arm +# RUN: rm -rf %t && split-file %s %t +# RUN: llvm-mc -filetype=obj -triple=armv7-a-none-eabi --arm-add-build-attributes %t/a.s -o %t/a.o +# RUN: ld.lld -pie -T %t/lds %t/a.o -o %t/a +# RUN: llvm-objdump -d --no-show-raw-insn %t/a | FileCheck %s + +## We create a thunk for dest. +# CHECK-LABEL: : +# CHECK-NEXT: 2010004: b 0x2010008 <__ARMV7PILongThunk_dest> +# CHECK-EMPTY: +# CHECK-NEXT: <__ARMV7PILongThunk_dest>: +# CHECK-NEXT: 2010008: movw r12, #65516 +# CHECK-NEXT: movt r12, #65023 +# CHECK-NEXT: add r12, r12, pc +# CHECK-NEXT: bx r12 + +## The first instruction can reuse the thunk but the second can't. +## If we reuse the thunk for b, we will get an "out of range" error. +# CHECK-LABEL: : +# CHECK-NEXT: 4010000: bl 0x2010008 <__ARMV7PILongThunk_dest> +# CHECK-NEXT: b 0x4010008 <__ARMV7PILongThunk_dest> +# CHECK-EMPTY: +# CHECK-NEXT: <__ARMV7PILongThunk_dest>: +# CHECK-NEXT: 4010008: movw r12, #65516 +# CHECK-NEXT: movt r12, #64511 +# CHECK-NEXT: add r12, r12, pc +# CHECK-NEXT: bx r12 + +#--- a.s +.section .text_low, "ax", %progbits + +.globl _start +_start: + nop +dest: + bx lr + +.section .text_mid, "ax", %progbits +mid: + b dest + +.section .text_high, "ax", %progbits +high: + bl dest + b dest + +#--- lds +SECTIONS { + .text_low 0x10000: { *(.text_low) } + .text_mid 0x2010004 : { *(.text_mid) } + .text_high 0x4010000 : { *(.text_high) } +}